Download the list of spare parts for the machine A1-BZN, A1-BZ-2N, A1-BZ-ZN
Depending on the technological purpose, the working surface of the grinding rollers is grooved or smooth. The design of the machines provides for water cooling of fast-rotating grinding rollers and the possibility of re-cutting grooves without dismantling the bearings.
Remote control of the halt and blade of the grinding rollers allows you to stabilize the grinding mode and practically eliminates interference service personnel in the operation of roller machines.

Roller machine type A1 - BZN - is the most common grinding machine in Russian flour mills. Depending on the modification and design, the machines may differ from each other. The main distinguishing features of machines of type A1 - BZN are the location of the drive under the interfloor ceiling or on the same floor where the machine is located; method of removing the crushed product - with a lower intake - by gravity and an upper intake - into the risers of pneumatic transport installations; roller surface relief - with grooves or micro-roughness; type of level switch used, etc. The roller machine type A1-BZ-2N has two pairs of grinding rollers located obliquely (at an angle of 300) to the horizontal. The length of the rollers is 1000 mm, and the diameter of the barrel is 250 mm. The rollers are water-cooled with full or partial recirculation. Cleaning the rollers from adhering product is carried out either with a knife for micro-rough rollers, or with a brush for grooved ones. The crushed product is removed from the machine through an outlet device, which includes a hopper or a pneumatic receiver. The drive of the fast-rotating drum is carried out from an electric motor through a V-belt transmission, and the slow-rotating drum is driven from a fast-rotating one through a helical gear, providing a peripheral speed ratio of 1.25 or 2.5. The control mechanisms for regulating the interroller gap are displayed on the front panel. In this case, the halt and dump of the rollers can be carried out both manually and automatically. To implement the latter, a level indicator, a power supply and signal conversion unit, and an actuator - a pneumatic cylinder controlled by an electromagnetic valve - are used. The food supply for each half of the machine is autonomous.

Roller machines type A1-BZN are available in three modifications for use in various flour mills.

Roller machine A1-BZN. Designed for use as part of a set of equipment for a new flour mill. The machines are installed in groups of four to five machines with common hoods. A set of machines with different designs and the sequence of their installation are regulated by the design of a typical flour mill. The electric motors of these roller machines are installed on a special platform under the interfloor ceiling. The crushed product is discharged downwards. The A1-BZN roller machine has 21 designs.

The roller machine A1-BZ-2N (Fig. 53) consists of the following main units of grinding rollers; roller drive; mechanisms for adjusting and parallel approach of rollers; roller dump-dump systems; receiving and feeding device; beds.

Grinding rollers (Fig. 54). Installed in pairs in both halves of the frame. Moreover, the line connecting the centers of the end circles of the rollers forms an angle of 30° with the horizontal. As this angle decreases, the power conditions for the roller pair improve and the filling factor of the grinding zone increases. The length of the roller is 1000 mm, and the nominal diameter of the barrel is 250 mm. The weight of the hollow drum is 270 kg, approximately 30% less than the solid one.

Roller 10 (Fig. 55) is a two-layer hollow cylindrical barrel. Roller barrels are cast from cast iron using a centrifugal casting machine.

The diameter of the internal cavity of the barrel is 158 mm, the depth of the outer bleached layer (working) is 10 mm. Trunnions 9 are pressed into both ends of the barrel; the diameter of the pressed part is 160 mm. The journal neck has three parts: a transition cylindrical with a diameter of 100 mm, a support consisting of cylindrical and conical parts (75...80 mm), and an end cylindrical 65 mm. Bearings 12 are installed on the conical part 13 of the axle, and the end cylindrical part is used to attach the drive pulley or gear 4 of the interroller transmission.

The cooling system of the upper roller (see figure) is as follows. The upper roller 10 is cooled by water entering through the cantilever tube 8, which is inserted at the free end through the axial hole in the trunnion 9 into the internal cavity of the roller 10. A plug valve is installed inside the housing in the supply line, which regulates the water supply to the internal cavity of the roller.

Warm water is removed through an annular gap between the fixed tube 8 and the rotating bronze bushing 2 with a conical socket. The heated waste water enters the drain chamber, is discharged through a pipe into the cooling device and returns to the recirculation system.

The roller is cooled as follows. Water, through a tap that regulates the flow, enters an isolated chamber, from where it enters a tube through a radial hole and is sprayed from it into the drum cavity. The centrifugal forces of inertia that arise when the drum rotates contribute to good washing of its internal cavity and heat removal. During normal operation of the cooling system, the temperature of the rapidly rotating drum should not exceed 60°C. According to test data, the surface temperature of the roller does not exceed 36°C, and the product after grinding does not exceed 25°C.

Cooling the rollers has a positive effect on the technological performance of grinding. Reducing the temperature in the grinding zone prevents drying out of the shells and overheating of the grinding products. Reducing moisture transfer stabilizes the moisture content of the grinding products, and accordingly, the accumulation of static electricity charges is reduced. Reduced thermal expansion of cooled rollers ensures stable working gap. To improve heat transfer, the inner surface of the roller must be processed so that there are no deep cavities, burrs and other irregularities.

Cleaning the rollers. During the grinding process, cakes of crushed parts of the grain stick to the working surface of the rollers. To clean the grooved rollers of all systems except I, II, torn 12th grinding, brushes 13 are installed (see Fig. 54) from polymer material. Micro-rough rollers and rollers of the 12th grinding system are cleaned with knives 11. To improve the conditions for starting a natural electric motor, it is necessary that the knives come into contact with the surface of the rollers only after a halt. This is achieved by blocking the movement of the knives with the rotation of the eccentric shaft using cables. The gap between the rollers and knives should not exceed 0.02 mm.

Roller drive. The roller drive mechanism consists of an upper roller drive and an interroller transmission. The torque from the electric motor is transmitted by a V-belt transmission to the driven pulley 21 (see Fig. 53), which is installed on the right axle of the upper rapidly rotating roller and secured with a wedge key. The diameter of the drive pulley for driving grooved rollers is 150 mm, and for micro-rough rollers

There are two options for installing the electric motors of the A1-BZ-2N machine: directly on the ceiling where the roller machine is installed, and under the ceiling on a special platform. The inter-roller transmission is a gearbox consisting of two helical gears 55 mm wide. The angle of inclination of the teeth is 16°10ґ, the normal module is m=6, and the engagement angle is 15°.

The mechanism for adjusting the inter-roll gap and parallel approach of the rollers is shown in Fig. 8.3. Using the steering wheel 6, the rollers are adjusted for parallelism. Screw 1 allows for precise adjustment of the working gap. The elbow-shaped lever 9 is pressed against the rod stop 10 using a safety spring. If solid objects up to 5 mm get into the gap between the rollers, the spring will allow the rollers to be pressed out. The maximum change in the gap between the rollers by the parallelism adjustment mechanism is 4.4 mm. The sensitivity of the mechanism is characterized by the change in the gap per revolution of the steering wheel and is equal to 0.22 mm. If the grinding along the length of the rollers is not uniform, by rotating the steering wheel 11 the ends of the rollers are raised or lowered, leveling the working gap between them.

The roller rest-dump system provides automatic and manual separation of the rollers from each other in the absence of a product (or when starting the machine), which prevents the possibility of the rollers touching. In automatic mode, the “halt - dump” operation is carried out using a pneumatic cylinder, a capacitive sensor and an electronic control unit.

The capacitive sensing element 8 (see Fig. 54) of the level switch is installed in the receiving pipe of the rolling machine. The product located in the receiving pipe changes the electrical capacitance of the sensing element, which generates a control signal. Its value directly depends on the degree of filling of the machine neck with the product entering the grinding process. The control signal is converted to DC voltage and amplified in the electronic unit circuit. At a certain signal value, the relay contacts close. As a result, the electromagnetic valve 15 (see Fig. 53) opens access to compressed air under a pressure of 0.5 MPa to the piston of the pneumatic cylinder 18. The piston lifts the rod and, through a system of levers, rotates the eccentric shaft 22 to the rest of the lower roller.

When the product level in the receiving pipe decreases to a certain limit, the control signal becomes insufficient in magnitude to keep the relay contacts in the closed state. Valve 15 blocks the access of compressed air to the pneumatic cylinder, the piston and rod are lowered, and the mechanism operates to release the drum.

When the machine is operating in automatic mode, it is possible to force the drum to fall off using a manual pneumatic switch, which quickly relieves pressure in the pneumatic cylinder through a two-way air distributor.

The receiving and feeding device consists of a receiving coarse, a roller feeding mechanism with a drive, a damper and a product supply control system.

The receiving pipe 6 (see Fig. 54) is a glass cylinder with a diameter of 298 mm, installed in the neck 7 of the roller machine. The receiving pipes of roller machines serving various technological systems are separated by a vertical partition, which provides autonomous power to each half of the machine

A sensitive element 8 of a product level indicator is installed in each half of the pipe.

The feed mechanism, depending on the physical and mechanical properties of the initial product in machines of various technological systems, has seven designs and includes a roller feeder, a gearbox (speed switch), a damper and a drive in various combinations. The feeder is made in three versions: dosing and intermediate rolls (for the first torn system); dosing roller with auger (Fig. 58) (for other tattered systems); dosing and distribution rolls (for grinding systems).

The diameter of the rolls and auger is 74mm. On the surface of the dosing roller, longitudinal grooves are applied with a slope of 1°30º in the amount of 50, 30 or 20 depending on the technological system. The distribution roller has 50 transverse grooves with a pitch of 2 mm.

The auger is made in the form of a shaft with blades mounted perpendicular to its axis. Only the outer blades are located so as to slightly delay the movement of the product in the axial direction.

The intermediate roll has no cutting, it is isolated from the product supply zone and performs only kinematic functions. All roller-screw and twin-roller feeders for the 11th and 12th grinding systems have gearboxes for four-position control of the speed of the dosing roller.

The rotation speed of the dosing roller of the feeding mechanism is set so that the layer of product is thin, but distributed along the entire length of the roller.

The valve 9 (see Fig. 54) with a serrated edge (for machines of torn systems, except I and IV fine) or smooth (for all other systems) forms a feeding gap with the metering roller 3, which is set manually with a regulator 10 placed on the inside sides of the machine.

The roller machine bed is made of cast iron collapsible design. It consists of two sidewalls, two longitudinal walls and a traverse. The frame parts are connected to each other with bolts. The sidewalls have holes and openings to accommodate moving and fixed components of the machine.

The machine is completely enclosed by a hood, which is made of four removable lower and four folding upper stamped steel guards.

The operation of roller machines begins with the start of the electric motor, from which rotation is transmitted via V-belts to the pulley of the upper roller, and from it through the interroller gears to the lower roller. From the hub of the upper roller pulley, rotation is transmitted by a flat belt to the feed roll pulley, and from it to the drive half of the dog clutch.

When the receiving pipe is filled with product, the capacitive sensing element of the level switch ensures the closure of the circuit of the solenoid valve, which connects the compressed air line to the working cavity of the pneumatic cylinder. In this case, the piston will move the rod upward, and from it, through a system of levers, the eccentric shaft will rotate and lift the “elbow” of the movable bearing housing, as a result of which the lower roller will stall.

Under the action of a spring, the driven half of the cam clutch engages with the driving half of the clutch and rotation through the gears is transmitted to the feed rollers to supply the original product for grinding. Under the influence of the mass of the product, overcoming the resistance of the spring, the curtain sensors feed through a system of levers, turn the valve and the product begins to flow through the gap between it and the dosing roller.

When the flow of product into the receiving pipe of the machine stops, the circuit of the electromagnetic valve will open and the grinding rollers will fall off through a system of levers. At the same time, the light on the machine’s control panel will light up, indicating idling.

In the production of flour, the process of grinding grain and intermediate products is one of the main ones, as it significantly affects the yield and quality finished products. Grain grinding is one of the most energy-intensive operations. Technological methods and machines used for grinding largely determine the technical and economic indicators of a flour mill.

When choosing equipment and general characteristics During the grinding process on roller machines, a standard indicator of the average specific load is introduced, which is determined by the ratio of the daily productivity of the grinding department of the flour mill to the total length of the grinding line. For roller machines A1-BZN this load is 70...75 kg/(cm·day).

Electricity consumption cannot be determined analytically, but certain practical standards have been established for specific energy consumption per 1 ton of finished product for the plant as a whole.

The main indicators of the efficiency of a roller machine are influenced by the ratio of the peripheral speeds of the rollers (differential), the condition of the surface, and the accuracy of the gap along the length of the rollers. Increasing the peripheral speeds of the rollers with a constant differential significantly increases productivity, slightly increases energy consumption and has virtually no effect on the granulometric composition of the crushed product. The peripheral speed of rapidly rotating corrugated rollers is 5.5...6 m/s, and micro-rough rollers - 5.2...5.4 m/s.

The differential has a significant impact on the productivity and nature of grinding. As the differential increases, the destruction of particles due to shear deformation predominates; as the differential decreases, the role of compression deformation increases.

The quality and productivity of a roller machine is greatly influenced not only by the size of the gap, but by the constancy of its size along the entire length of the rollers. The correct cylindrical shape of the rollers is ensured when grinding on special grinding and groove machines. The consistency of the gap can also be influenced by the condition of the bearings, shock absorber springs and hinge joints.

The quality of grinding is negatively affected by the radial runout of the rollers, which may be a consequence of the irregular geometric shape of deviations during pressing of axle shafts, casting defects causing unbalance. The smaller the radial runout of the rollers, the more stable the working gap, the higher the grinding quality, and the greater the wear resistance of the rollers. Therefore, the roller processing technology necessarily includes their dynamic balancing on a special machine.

An important condition for the implementation of all successive technological stages of grain grinding is to ensure the specified parameters of the corrugated micro-rough surface of the rollers, which for each technological system are recommended by the Rules and taken into account in the design of the roller machines. The grooves are cut on a grinding and groove machine, and the micro-rough surface is applied with a jet of compressed air and abrasive material on a machine with a special sandblasting device.

Roller machine ZM2 two-section(fig.) with automatic performance control is designed for grinding grain and intermediate grinding products in flour mills.

Rice. Roller machine ZM2

The machine includes: bed 7; rollers 3 and 28; distribution 4 and dosing 5 rollers; aspiration device 2; levers 6, 11, 15, 23; screws 7,17, 24; bar 8; sector damper 9; springs 10, 22; supply pipe 12; sensors 13 and 14; rough landing mechanism 19; mechanism 25 for adjusting and aligning the movable roller; inter-roller transmission 26; eccentric shaft 27 and electric motor 29.

The grinding rollers consist of two steel axle shafts and a working drum made of nickel-chromium cast iron, the outer surface of which is bleached. Rollers 3 and 28 in frame 1 are mounted on roller bearings so that there is an angle of 45° between the line connecting the axes of the rollers and the horizontal. One of each pair of rollers has only rotational motion (fast-rotating), the second (slow-rotating), in addition to rotational, can also have translational motion in the direction perpendicular to the axis. This ensures regulation of the gap between the rollers, its uniformity along the length of the rollers, rapid approach (halt) and removal (dump), as well as the passage of solid foreign objects between the rollers without breaking machine parts and damaging the rollers. The rollers are connected to each other by a gear transmission. Clean the rollers with brushes 30.

The rollers are adjusted for parallelism using screw mechanisms. An eccentric mechanism is used to bring the rollers closer together in parallel. Solid foreign objects pass between the rollers due to a short-term increase in the gap when the shock absorber spring is compressed, installed under the movable drum arm.

The feeding mechanism of the machine is two-roller. Distributing roller 4 has multi-directional (left and right) screw grooves, and dosing roller 5 has 35 longitudinal grooves around the circumference on torn systems and 59 grooves on grinding systems. The feed control mechanism allows you to automatically change the supply of product by the dosing roller depending on its entry into the supply pipe.

The feeding mechanism is driven by a flat belt transmission from the hub of a rapidly rotating roller, and the metering mechanism is driven by a distribution mechanism through a gear transmission. The gap between the sector valve and the camshaft is adjusted manually.

Roller machines of the ZM2 type are produced with a mechanical automatic machine, which ensures the following operations:

Dump and rest of the movable roller;

Turning off and on the rotation of the feed rollers;

Closing and opening the sector damper.

The dump and rest of the rollers are accompanied by a light alarm. When dumping, the red warning lights come on. When the machine is idling, the warning lights are on, while in operating mode they are off.

To regulate the supply of product above the metering roller 5, a sector damper 9 is hinged on the lever 6, which is connected by a rod 18 and levers 11 and 15 to a power sensor 13 located in the supply pipe of the machine. To return the damper to the lower (closed) position, a spring 10 is used, the force of which can be changed by rearranging its lugs in the holes of the support bar on the valve 16. To regulate the amount of movement (stroke) of the sector damper, a screw 17, fixed to the valve 16, is used.

The right crank of lever 6 is connected through an earring 20, a screw 24, a shock-absorbing spring 22, a lever 23, a shaft 21 with the automatic control lever. The left crank of lever 6, through bar 8, rests on screw 7, fixed to the frame, which limits the movement of the sector damper when closing it and prevents breakage of parts.

Preliminary setting of the size of the supply gap is carried out by rotating the screw 24. Additionally, the supply gap during operation of the machine (when cleaning the supply hopper) is increased by pulling screw 24 by the handwheel “toward yourself”.

The inclusion of a rough stop of the rollers, the rotation of the rollers 4 and 5, as well as the movement of the sector valve 9 are performed automatically when the supply pipe is filled with product. Reverse processes also occur automatically when the flow of product into the supply pipe of the machine stops.

Technical specifications machines type ZM2

Productivity, t/day......60... 100

corrugated...............490

smooth...............390

Air consumption for aspiration, m 3 /h........600

Drive motor power

rollers of one half, kW......15.0...22.0

Overall dimensions, mm...................1800x1470x1390

Weight, kg...................2550...3350

Roller machine A1-BZN(Fig.) are used as part of complete equipment at flour mills with an increased yield of high-grade flour and are installed in groups of four and five machines with common hoods.

The roller machine consists of the following main units: grinding rollers; roller drive; mechanisms for adjusting and parallel approach of rollers; roller dump-dump systems; receiving and feeding device; beds.

Grinding rollers 8 are installed in pairs in both halves of the machine. Moreover, the line connecting the centers of the end circles of the rollers forms an angle of 30° with the horizontal. As this angle decreases, the power conditions for the roller pair improve and the filling factor of the grinding zone increases.

The grinding rollers are made in the form of a barrel with pins pressed into it on both sides. The surface hardness of barrels for grooved and smooth rollers is 490...530 and 450...490 HB, respectively. The barrels and pins are hollow. The depth of the upper bleached layer of barrels is 10...20 mm. The nominal size of the barrels is 250x1000 mm. The rollers in the machine are positioned at an angle of 30° to the horizontal.

Radial and axial loads acting on the grooved rollers when crushing the product are carried by bearings. Bearings 1 of the two upper rollers (one in each half of the machine) are attached to the sidewall with bolts, two of them being tight-fitting. The lower roller of each half of the machine can move relative to the upper one. This makes it possible to adjust the size of the gap between the rollers, as well as to ensure instantaneous dumping of the lower roller when the product supply stops, which avoids the dangerous operation of the rollers “corrugated on corrugations”. For this purpose, housings of moving bearings b and 10 are mounted on axles 9, pressed into the holes of the sidewall. The moving bearing housings have detachable covers. One of the housings of these bearings mates with the trunnion through an eccentric sleeve 7, the rotation of which changes the relative position of the grinding rollers and achieves parallelism.

The housings contain spherical roller bearings 11, the inner races of which are mounted on the conical parts of the roller journals. The bearings are removed from the conical part of the axle using a special hydraulic puller. It pumps oil through the hole in the drum journal to the point where it mates with the conical surface of the inner race. At the left ends of the axles, gears 3 and 5 of the interroller transmission are fixed, which are covered with a casing 4.

Rice. Grinding rollers with bearing units, drive and interroller transmission

The torque from the electric motor is transmitted by a V-belt transmission to the driven pulley 13 of the upper rapidly rotating roller. For the drive, narrow V-belts UA-4500-6 are used. The gears and pulley are secured to the axles with keys 12. The diameter of the drive pulley for grooved rollers is 150 mm, for smooth rollers 132 mm.

Housing 2 (Fig.) of the fast-rotating roller cooling device is attached to the inter-roller transmission casing.

Rice. Cooling device for the roller of the ZM2 machine

The cantilever tube 1 is inserted into the hollow roller and is rigidly attached to the body at one end. A plug valve 3 is mounted inside the housing (in the supply line), with the help of which the water supply to the internal cavity of the drum is regulated. The drainage of water from the roller into the housing is ensured by a nozzle 5 screwed into the threaded hole of the trunnion.

When replacing the rollers, the water supply is shut off with valve 4 attached to the vertical supply pipe.

The roller is cooled as follows. Water, through a tap that regulates the flow, enters an isolated chamber, from where it enters a tube through a radial hole and is sprayed from it into the drum cavity. The centrifugal forces of inertia that arise when the drum rotates contribute to good washing of its internal cavity and heat removal. During normal operation of the cooling system, the temperature of the rapidly rotating drum should not exceed 60 °C. According to test data, the surface temperature of the roller does not exceed 36 °C, and the product after grinding does not exceed 25 °C.

Cooling the rollers has a positive effect on the technological performance of grinding. Reducing the temperature in the grinding zone prevents drying out of the shells and overheating of the grinding products. Reducing moisture transfer stabilizes the moisture content of the grinding products, and accordingly, the accumulation of static electricity charges is reduced. Refrigerated products are less likely to condense moisture in gravity pipes and sieving screens. Reduced thermal expansion of cooled rollers ensures stable working gap. To improve heat transfer, the inner surface of the roller must be processed so that there are no deep cavities, burrs and other irregularities.

The grain feeding device is made: for the first torn system in the form of a metering and intermediate roller, for other systems with grooved rollers (except for the 12th grinding) in the form of a combination of a metering roller and a screw; for grinding systems in the form of a combination of distribution and dosing rollers. The drive of the grain feeder is provided by a flat belt drive.

Changes in the gear ratio of the gearbox and, consequently, in the rotational speed of the dosing roller on machines of grinding systems (except for the first) and the 11th, 12th grinding systems are achieved using a mechanism with a draw key, controlled by a handle through a rack and pinion gear. Other versions of product feeders do not have a key in the gearboxes. Rotation from the driven pulley of the flat belt drive to the gearboxes is transmitted through a cam clutch, the engagement of which is blocked with the rough stop of the rollers by means of levers and a fork.

For automatic control of grain supply(Fig.) A damper 1 is suspended on hinges above the metering roller 5. It is connected through levers, a roller, a bracket and a roller to a power sensor 3, made in the form of two curtains.

Rice. Device for automatic control of grain supply

To regulate the effect of grain and, consequently, the sensitivity of the alarm, spring 6 is used. The deformation of the latter is changed by moving the nut 7 relative to screw 8. For machines of torn systems (except I and IV fine), the edge of the damper is serrated, for machines of other systems it is smooth. The range of automatic movement of the damper is adjusted by limiting screw 2. A probe 4 is installed in the grain entry area (in the neck of the machine).

Roller parallelism adjustment mechanism consists of a flywheel 25 connected by a key to a bushing 26 (Fig.).

Rice. Mechanism for adjusting the parallelism of rollers in the A1-BZN rolling machine

A screw 27 is screwed into its threaded hole. One of the ends, which has rectangular guides, the screw is in contact with the roller of the lever 24 mounted on the eccentric shaft spike. Suspension 1 is hinged to the lever.

Safety springs 33 are mounted on it, ensuring safe passage between the rollers of foreign bodies with a diameter of up to 5 mm. The free end of the movable bearing housing 31 rests on the upper end of the safety springs.

The device also includes: bolts 9 and 10; limit screw 11; levers 2, 3, 8, 13,14, 24; air distributor 15; roller 16; bracket 17; screws 7,19, 27; nut 20, neck 22 of the machine; bearings23, 32; sidewall29 of the bed.

The mechanism ensures parallel approach of the rollers after they are adjusted. A rough stop of the rollers is achieved by rotating the eccentric shaft manually (by the handle of the screw 7 connected to levers 2 and 3, forming a parallel approach mechanism) or from the rod of the pneumatic cylinder 34.

In the first case, the latch 6 on the lever 2 engages with the stop 4 and ensures the rolled position of the rollers. In the second case, by rotating the eccentric 5, the engagement of the latch 6 with the stop 4 is prevented, and the roller stop is provided with compressed air with a nominal pressure of 5-10 ~ 5 Pa. The working cavity of the pneumatic cylinder can be connected to a compressed air line or the atmosphere through an electro-pneumatic valve 30. The compressed air pressure in the cylinder is controlled by a pressure gauge on the control panel. The rough blade of the rollers is provided by the spring and mass of the lower roller.

The level switch consists of a probe, a head 21 and a relay unit 28. When the feed pipe is filled with grain, the level switch allows for automatic activation of the rough roller stop and rotation of the feed devices. Reverse processes also occur automatically when the flow of grain into the supply pipe stops. Local control of the rough stop is carried out by a two-way air distributor, the handle of which is located on the front panel of the machine.

The idle speed alarm is provided by the automatic lighting of the light located on the front panel.

As grain enters the supply pipe, the electrical capacitance of the probe 4 changes. The probe capacitance is converted by the electrical circuit of the head 21 into voltage, which controls the operation of the relay unit 28. This ensures the operation of the electro-pneumatic valve, the drive mechanism of which connects the compressed air line with the working plane of the pneumatic cylinder. The piston moves the rod upward, and from it (through screw 7 and levers 2, 3) the eccentric shaft rotates. The spikes of the latter move upward the lever 24, the suspension 1, the safety spring 33 and the free ends of the movable bearings 32. The rollers stall. At the same time, lever 8 releases lever 14 and fork 12.

Under the action of a spring, the driven half-coupling of the cam clutch engages with the driving half-coupling and rotation through the gearboxes begins to be transmitted as follows: in machines of the first torn system - through the intermediate roller to the metering roller; in machines with grooved rollers of other systems - a screw and a dosing roller; in machines with smooth rollers - dosing and distribution rollers for feeding grain for grinding.

Under the influence of the grain mass, overcoming the resistance of the spring 18, the power sensor 3 moves the roller, levers, and roller. As a result, damper 1 is rotated through the nut and screw and grain enters the gap between it and the metering roller. As the mass of grain entering the supply pipe decreases, the pressure on the sensor decreases. As a result, under the action of the spring 18 and its own weight, the damper 1 is lowered towards the metering roller 5, reducing the grain supply.

If the grinding at the ends of the rollers is not the same, then by rotating the flywheel 25 the free ends of the movable bearing housings are raised or lowered, i.e., the working gap between the rollers is leveled. When grain stops flowing into the supply pipe, the probe capacity changes. In this case, the probe head and the relay unit open the circuit of the electro-pneumatic valve. As a result, the supply of compressed air to the pneumatic cylinder stops and, under the action of a spring through the eccentric shaft, the corresponding levers and screw cause the rollers to fall off.

On different systems, the rollers differ from each other in the parameters of cutting grooves. This ensures high technological efficiency.

In addition, the design of roller machines differs in the grain feeding device, taking into account its characteristics, the power of electric motors, and the type of cleaners. The electric motor of the roller machine on the first torn system is the most loaded. Its power is 18.5 kW. On subsequent systems, the power of the electric motors decreases in accordance with the decrease in the amount of crushed product. Distinctive features include the difference in the design of the hoods and the diameter of the drive pulleys.

During the grinding process, cakes of crushed parts of the grain stick to the working surface of the rollers. For cleaning grooved rollers of all systems, except for I, II torn; 12th grinding machine, 30 brushes made of polymer material are installed. The micro-rough rollers and rollers of the 12th grinding system are cleaned with knives. To improve the starting conditions of the drive electric motor, it is necessary that the knives come into contact with the surface of the rollers only after a halt. This is achieved by blocking the movement of the knives with the rotation of the eccentric shaft using cables. The gap between the rollers and knives should not exceed 0.02 mm.

The size of the gaps between the rolled rollers is checked at a distance of 50...70 mm from their ends (the size of the gap should be for the I torn system, mm: 0.8... 1.0; for the II torn system - 0.6...0 .8; for III torn coarse - 0.4...0.6; for torn fine - 0.2...0.4; for grooved rollers of grinding systems - 0.1...0.2; for smooth rollers - 0.05). The gaps between the valve and the metering roller should be no more than 0.35 mm on torn systems, and no more than 0.15 mm on grinding systems. The gaps between the rollers and knives should not exceed 0.02 mm.

The form of execution of rolling machines includes the following variable parameters:

combination of machine halves for a specific technological system;

the nature of the working surface of the grinding rollers (corrugation or micro-roughness parameters);

ratio of peripheral speeds of grinding rollers - differential (2.5 or 1.25);

method of cleaning grinding rollers (knife, brushes);

options for the device for feeding the initial product (type of roller feeder, presence of a gearbox, damper edge, diameters of flat-belt pulleys);

electric motor power of each half of the machine; diameters of drive pulleys (150 and 132 mm); option for installing the electric motor (on or under the ceiling); method of capping roller machines (group, individual). Setting up and adjusting the machine is as follows. Before starting the roller machine, check: the presence of lubrication, the operation of the moldboard mechanism, the absence of jamming of the rollers (when rotating them manually); fastening of threaded and other connections; correct installation and uniformity of the working gap between the rolled stationary rollers at a distance of 50...70 mm from their ends; movement of roller cleaners during dumping and dumping; condition of drive belts.

When the roller machine is operating under load, check: the operation of the rest of the fender-dump mechanism from the pneumatic switch, from the local and remote control, in automatic mode; blocking the inclusion of feed rollers and movement of the damper; heating of bearings (temperature no more than 60 °C); operation of electrical circuits and equipment, water supply, operation of inlet and outlet communications and transport devices.

Setting up and operatively regulating the grinding mode of each half of the machine under load comes down mainly to regulating the power system and the working gap between the grinding rollers.

For machines that have a gearbox in the power mechanism, first set the minimum speed of the metering roller and then select the optimal rotation speed. Changing gears on the go is not allowed.

In accordance with the distribution of loads across technological systems, using a regulator, the minimum value of the supply gap between the valve and the metering roller is manually set: on torn systems - 0.35 mm, on grinding systems - 0.15 mm. The maximum supply gap set by the limit screw should provide an upper limit for the supply of the initial product, at which the current load of the electric motor, as measured by the ammeter, would not exceed 80% of the rated one. If this condition is not met, the supply gap must be reduced.

Regulation of the power supply system and working gap should be carried out with constant monitoring of the electric motor load, as well as the inlet and outlet transport systems.

On machines of grinding systems, the uniformity of product distribution along the length of the distribution roll is visually checked. On each half of the roller machine, the extraction is checked, which must correspond current Rules.

When setting the grinding mode, check the sensitivity of the automatic system for regulating the supply of initial grain in the established range, the location of the product cone in the receiving pipe relative to the sensitive element of the level switch.

After setting the grinding mode, the locking devices of the control elements must be tightened. In the future, the grinding mode should not be adjusted for a given grinding batch, which should provide stable results over a long period of time.

Distinctive features roller machines of type A1-BZN from previously produced domestic models are as follows:

the rollers are made hollow, which reduces the metal consumption of the machines; improved nutritional conditions;

the presence of water cooling of fast-rotating rollers creates a stable thermal regime in the grinding zone, which has a beneficial effect on the quantitative and qualitative indicators of the grinding process, while the bearings are cooled;

a set of design features, high precision processing, the use of a wear-resistant working layer of rollers significantly increases their durability: corrugated - up to three years, smooth - up to ten years;

automatic system the lower roller dump shaft is interlocked with the source product feed control system, which allows you to remotely control the machine, ensuring stability and reliability of its operation;

The use of a conical bearing fit allows them to be dismantled using a hydraulic puller. The presence of a horizontal connector in the bearing housing makes it possible to remove them together with the bearings. The labor intensity of this operation is significantly reduced;

in the design forms of roller machines with a large number of variable parameters, the specifics of each technological system are taken into account as much as possible;

the presence of three models of roller machines: A1-BZN, A1-BZ-2N and A1-BZ-ZN - increases their versatility and scope of use.

Technical characteristics of machines type A1-BZN

Productivity, t/day........84

Water consumption for cooling half of the machine, m 3 /h, no more...............0.3

Rotation speed of fast-rotating rollers, min -1:

corrugated...........................420...460

smooth.............. 395...415

Compressed air pressure, MPa........0.5

Air consumption for aspiration for the roller machine A1-BZ-2N, m 3 /min, no more.........10

Air consumption for pneumatic transport for half of the roller machine A1-BZ-ZN, m 3 /min, no more than......0.3

Electric motor power, kW, for systems:

I torn...............18.5

II torn, 1st and 2nd grinding.......15

III grinding, 1st and 2nd grinding, 3,4,6,8,9,10 grinding...............11

IV torn, 5...12-grind.......7.5

Overall dimensions, mm, no more...............1800x 1700x 1400

Weight, kg (without electric drive, hoods and electrical equipment) ...........2700

Roller machines type A1-BZN

Roller machines type A1-BZN are produced in three modifications for various flour mills. The machines are installed in groups of four to five machines with common hoods. The set of machines of various designs and the sequence of their installation in each group are regulated by the design of a typical flour mill. It is typical that the electric motors of these roller machines are placed on a special platform under the interfloor ceiling.

The roller machine type A1-BZN has 21 designs.

The A1-BZ-2N roller machine is used both at newly built and reconstructed flour mills to replace the ZM-2 machine. The A1-BZ-2N machine differs from the AI-BZN machine by the presence of individual hoods and the ability to install an electric motor on the same floor where the machine is located, as well as under the floor on a special platform. The machine has 39 designs.

The Al-BZ-ZN roller machine is used both at newly built and reconstructed flour mills to replace the BV-2 machine.

It differs from the machines described above by the presence of a device for the upper intake of the crushed product. This device consists of receiving pipes for suction of the product directly after grinding from bins under the rollers, and a pneumatic transport system. The A1-BZ-ZN roller machine has 22 designs.

The A1-BZN roller machine (Fig.) consists of the following main assembly units: grinding rollers, roller drive, inter-roller transmission, adjustment mechanisms and parallel approach of rollers, roller rest-dump system, receiving and feeding device and bed.

:
1 - exhaust pipe; 2 - product level indicator; 3 - damper; 4 - screw device; 5 - handle; 6 - steering wheel; 7 - locking head; 8 - cleaning knife; 9 - outlet hopper; 10 - cleaning brush; 11, 12 - slow and fast-rotating rollers; 13 - feed roller; 14 - auger; 15 - curtain sensors

The grinding rollers are installed in pairs in both halves of the machine. Moreover, the line connecting the centers of the end circles of the rollers forms an angle of 30° with the horizontal. The length of the roller is 1000 mm, and the nominal diameter of the barrel is 250 mm. The weight of a hollow roller is approximately 30% less than a solid one - 270 kg.

The roller is a two-layer hollow cylindrical barrel, the diameter of the internal cavity is 158 mm, the depth of the outer bleached layer (working) is 10 mm. Trunnions are pressed into both ends of the barrel. Bearings are installed on the conical part of the trunnion. The end cylindrical part is used to attach the drive pulley or inter-roller gears. Tubes with cooling water are inserted into the journals of the rapidly rotating roller.

The grinding rollers rotate in double-row spherical roller bearings with tapered inner races. The bearing is removed from the conical part of the axle using a hydraulic puller, which forces oil through a hole in the axle to the point where it meets the surface of the inner race of the bearing. The bearing housings of the upper roller are attached to the side of the frame with four bolts, and the bearing housings of the lower movable roller have free ends (elbows) supported by safety springs. The lower roller housing is detachable, which allows the rollers to be removed along with the bearings.

The device for cooling the upper rapidly rotating roller operates as follows (Fig.). Roller 6 is cooled by water entering through tube 5, which is inserted at its free end through an axial hole in the trunnion into the internal cavity of the roller. The tube has two holes for spraying water inside the drum. The open end of the tube is rigidly connected to the housing 7. Inside the housing, a plug valve is installed in the supply water pipe, which regulates the water supply to the internal cavity of the roller. Warm water is discharged through an annular gap between the stationary tube 5 and the rotating bronze bushing 2 with a conical socket. The waste water enters the drain chamber, is discharged through a pipe into the cooling device and returns to the recirculation system. Heated water can be used to moisten grain in the preparatory department of a flour mill.

The centrifugal forces of inertia that arise when the drum rotates contribute to good washing of its internal cavity and heat removal. During normal operation of the cooling system, the temperature of the rapidly rotating drum should not exceed 60 °C. According to test data, the surface temperature of the roller does not exceed 36 °C, and the temperature of the products after grinding does not exceed 25 °C.

Cooling the rollers has a positive effect on the technological performance of grinding. Reducing the temperature in the grinding zone prevents drying and excessive grinding of the shells, as well as overheating of the grinding products. Water consumption for cooling does not exceed 0.6 m3/h for one roller mill. However, water cooling of rollers is now being phased out in practice for reasons related to economics and additional labor costs.

1 - body; 2 - bronze bushing; 3 - inter-roller gears; 4 - bearing; 5 - tube; 6 - axle; 7 - roller

Leading foreign companies achieve almost the same results by introducing an active aspiration system, etc.

In production conditions, it is necessary to control the heating temperature of the rollers and the crushed product. If the temperature of the product increases above normal after passing it through the roller machine, it is necessary to identify the cause of the violation technological process: wear of the working surface of the rollers, non-parallelism of the rollers, uneven filling of the grinding gap, disturbance in the cooling system of the rollers, etc.

During the grinding process, cakes of crushed parts of the grain stick to the working surface of the rollers. To clean the grooved rollers of all systems, except for the I, II, 12th grinding systems, brushes 10 made of polymer material are installed, and the smooth rollers are cleaned with knives 8 (see figure). The roller drive mechanism consists of an upper roller drive and an interroller transmission. The torque from the electric motor is transmitted by a V-belt transmission to the driven pulley, which is installed on the right axle of the upper rapidly rotating roller. The diameter of the drive pulley for grooved rollers is 150 mm, and for smooth rollers - 132 mm.

There are two options for installing electric motors: directly on the ceiling where the roller machine is located, and under the ceiling on a special platform (only the second option is suitable for the A1-BZN machine).

The inter-roller transmission is a gearbox consisting of two helical gears 55 mm wide. A large cast iron gear and a small steel gear are installed, respectively, on the left ends of the journals of the lower and upper rollers. Both gears rotate in oil poured into housing 10 (Fig.).

1 - neck; 2 - pulley; 3 - pneumatic switch of the dump-dump; 4 - damper spring; 5 - signal converter; 6 - feed mechanism pulley; 7 - gear shift handle; 8 - inter-roller gears; 9 - cooling system housing; 10 - inter-roller drive shaft; 11 - bearing housing; 12 - relay block; 13 - free end (elbow) of the movable bearing housing; 14 - air filter; 15 - solenoid valve; 16 - air ducts; 17 - safety spring; 18 - pneumatic cylinder; 19 - “Start”, “Stop” buttons; 20 - bed; 21 - suspension; 22 - eccentric shaft; 23 - steering wheel for adjusting the parallelism of the rollers; 24 - handle for fine-tuning the inter-roller gap; 25 - traction; 26 - limit screw; 27- trunnion

The rollers are adjusted for parallelism by two screw-type mechanisms coupled with a parallel approach mechanism. When the steering wheel is rotated clockwise through the lever system, the suspension pulls the movable bearing elbow up and brings the rollers together at one end; when the steering wheel is rotated counterclockwise, the suspension lowers, rotates the lever around the eccentric shaft and retracts the lower roller. The locking head 7 (see figure) with the help of a handle fixes the installed position of the lower roller. The same operation is performed for the other end of the roller.

The maximum change in the gap between the rollers using the parallelism adjustment mechanism is 4.4 mm. The sensitivity of the mechanism is characterized by the change in the gap per revolution of the steering wheel and is equal to 0.22 mm. If the grinding along the length of the rollers is not the same, then by rotating the handwheels 6 the free ends of the movable bearing housings are raised or lowered, i.e., the working gap between the rollers is leveled.

The mechanism for parallel approach of the rollers is designed for precise setting of the working gap. The required working gap between the rollers is set by rotating the handle 5, which, through a system of levers, rotates the eccentric shaft so as to respectively bring the lower roller closer or away. The maximum change in the gap between the rollers by the parallel approach mechanism is 1.2 mm, and the sensitivity of the mechanism per revolution of the handle is 0.06 mm.

The roller-dump system provides automatic and manual control of these operations. In operating mode, there is automatic control of the roller dump - dump of the rollers. Manual stopping and dumping of the rollers is performed by raising and lowering handle 5 (see figure). The force applied to the handle is transmitted to the eccentric shaft and then, according to the scheme discussed above, a halt or dump occurs. The rest position of the roller is fixed by a latch, which engages with a stop pressed into the side of the machine.

If foreign bodies up to 5 mm in size enter the roller machine, a safety spring ensures their safe passage as a result of the rough dump of the lower roller.

Automatic control of the roller dump-dump includes two circuits: an electrical one, which measures the level of the product under the feeding mechanism and generates a corresponding electrical control signal, and a pneumatic one - acting through a system of levers on the eccentric shaft, which provides the dump-dump according to the scheme discussed above.

The electrical circuit consists of a product level indicator, a relay block 72 (Fig.) and an electromagnetic valve 75. The pneumatic circuit consists of an input filter 14, a pneumatic switch 3 and a pneumatic cylinder 18.
The product level switch is a capacitor with a certain capacitance. Changing the level of the product in the receiving pipe of the machine changes the capacitance of the alarm and, accordingly, the control signal, which is converted and amplified in the circuit of the electronic unit. At a certain value, the signal causes the relay contacts to close. A current of 220 V is supplied to the windings of the electromagnetic valve 75, which opens access to compressed air under a pressure of 0.50 MPa to the piston of the pneumatic cylinder 18. The piston lifts the rod and, through a system of levers, rotates the eccentric shaft 22 to the rest of the lower roller.

When the product level in the receiving pipe decreases to a certain limit, the control signal becomes insufficient in magnitude to keep the relay contacts in the closed state. The valve blocks access to compressed air into the pneumatic cylinder, the piston and rod are lowered and the mechanism is activated to release the drum. When the machine is operating in automatic mode, in emergency cases, forced dumping of the rollers is possible using a manual pneumatic switch 3.

The receiving and feeding device consists of a receiving pipe, a roller feeding mechanism with a drive and a damper, and a product supply control system.

The receiving pipe is a glass cylinder installed in the neck of the roller mill. The receiving pipes of the roller machines, serving two different technological systems, are separated by a vertical partition, which provides autonomous power to each half of the machine. A product level indicator is installed in each half of the pipe.

The product supply mechanism (Fig.), depending on the physical and mechanical properties of the initial product on various technological systems, has seven designs and includes a roller feeder, gearbox, damper and drive in various combinations.

The feeder can be made in three modifications: a dosing roller with intermediate rolls (for the first torn system), a dosing roller with a screw (for other torn systems) and dosing and distributing rolls (for grinding systems). Longitudinal grooves with a slope of 1°30" are applied to the surface of the metering roller. Depending on the technological system, there can be 50, 30 or 20 of them. The distribution roller has 50 transverse grooves with a pitch of 2 mm. The screw is made in the form of a shaft with blades. The intermediate roller does not has cuts, it is isolated from the product supply zone and performs only kinematic functions.

All roll-screw and twin-roll feeders for the 11th and 12th grinding systems have gearboxes for four-position control of the speed of the dosing roller. The rotation speed of the feed mechanism roller is set so that the product layer is thin and distributed along its entire length.

1 - handle; 2 - auger; 3 - spring; 4, 5 - cam coupling halves; 6 - pulley; 7 - flat belt drive; 8 - fast-rotating roller; 9 - traction with a leash; 10 - roll; 11 - gear block

The damper 3 (see figure) forms a feed gap with the metering roller, which is set manually using a screw device 4 and adjusted automatically. Automatic regulation of the supply gap of each half of the machine is carried out using two hinged corrugated curtain sensors 15 and a lever system. The more product enters the machine, the larger the supply gap, and vice versa. For each technological system, the range of automatic movement of the damper is manually set using a limit screw.

The drive of the product feeding mechanism (see figure) is carried out by a flat belt transmission 7 from the hub of the grinding roller drive pulley. Rotation is transmitted to pulley 6, on the same shaft with which two cam coupling halves 4, 5 are installed, which engage simultaneously with the halt of the slowly rotating roller. The feed rollers are mounted in plain bearings.

The bed of the roller machine is collapsible, cast iron, consists of two sidewalls, two longitudinal walls and a traverse. The frame parts are connected to each other with bolts. Holes and openings are made in the sidewalls to accommodate movable and stationary assembly units of the machine. The machine is completely enclosed by a hood, which is made of four removable lower and four folding upper stamped steel guards.

The operation of the machine begins with the start of the electric motor, from which V-belts transmit rotation first to the upper roller pulley, and then through the interroller gears to the lower roller. From the hub of the upper roller pulley, rotation is transmitted by a flat belt to the feed roll pulley, and from it to the drive half of the dog clutch.

When the receiving pipe is filled with product, the capacitive level switch ensures the closure of the circuit of the electromagnetic valve, which connects the compressed air line to the working cavity of the pneumatic cylinder. In this case, the piston lifts the rod upward, and from it, through a system of levers, an eccentric shaft rotates, which moves upward the free ends (elbows) of the lower roller bearings, as a result of which the grinding rollers stall.

Under the action of a spring, the driven half of the cam clutch engages with the driving half of the clutch and rotation is transmitted through the gears to the feed rollers. Under the influence of the mass of the product, the power sensor turns the valve through a system of levers, and the product begins to flow through the supply gap. When the flow of product into the receiving pipe of the machine stops, the electronic circuit opens the circuit of the solenoid valve and, through a system of levers, the grinding rollers fall off.

Grinding of grain and its grinding products

Purpose of roller machines for grain grinding

The process of grinding grain and intermediate products in the production of flour is one of the main and most energy-intensive operations, as it significantly affects the yield and quality of the finished product. Technological methods and machines used for grinding largely determine the technical and economic indicators of a flour mill.

At flour mills with complete equipment, grinding of grain and intermediate products is carried out on roller machines of the A1-BZN type. Roller machine - first technological machine grinding department, on which the productivity, efficiency and stability of subsequent technological and transport equipment largely depend.

The process of breaking solid bodies into pieces under the influence of impact or impact-abrasion, as well as compression and shear, is called grinding. The main requirements for the grinding process during varietal grinding of wheat grain are reduced to obtaining the maximum amount of intermediate products in the form of grains and duns High Quality, enrichment of the resulting intermediate products, their subsequent grinding into flour and grinding out the shells from the remaining endosperm particles. Depends on correct grinding rational use processed grain, quality of produced flour, energy consumption for flour production, productivity of grinding machines and technical and economic indicators of the flour mill.

Considering grain grinding as the basis of the technological process at a flour mill, we should not forget that it is organically connected with previous and subsequent grain processing processes, and first of all, with sorting, without which modern production of high-quality flour is impossible. Grinders are the main and most energy-intensive type of technological equipment.

The main factors influencing the process of grinding grain products in roller machines are the structural, mechanical and technological properties of the grain, the kinematic and geometric parameters of steam-operated rollers and the load on the machine. Among the indicators characterizing the structural, mechanical and technological properties of grain, the glassiness and moisture content of the grain mass have the greatest influence on the efficiency of the grinding process in roller machines.

Vitreousness characterizes the consistency of the endosperm of the grain, its structural, mechanical and technological properties, i.e. the behavior of the grain during the grinding process, its quantitative, qualitative and energy indicators. Grains with higher glassiness have increased strength and require greater energy costs for grinding.

Grain moisture also has a significant impact on the efficiency of the grinding process. It has been established that with increasing grain moisture, its resistance to destruction increases, microhardness decreases and specific energy consumption increases. When grain moisture increases from 14 to 16.5%, the yield of large fractions of intermediate products in cereal-forming systems decreases, the ash content decreases, while the specific energy consumption for grinding increases. Considering the significant improvement in the quality of intermediate products and flour due to less crushability of the shells, one should strive to increase the moisture content of the processed grain to possible limits.

The kinematic parameters include the peripheral speeds of the rapidly and slowly rotating rollers v6 and vM and their ratio K = vq/vm.

The geometric parameters of a roller machine include: the size of the gap between the rollers, the working surface of the rollers (grooved or micro-rough), the characteristics of the surface of the grooved rollers (the number of grooves per unit length of the roller circumference, the slope of the grooves, the profile of the grooves, the relative position of the grooves of paired rollers, the diameter of the rollers, the length of the rollers ).

The peripheral speeds of the rollers have a major influence on the speed at which forces are applied from the rollers to the product being crushed, as well as on the speed of processing the product in the working area of ​​the rollers. The peripheral speeds of the rollers determine the speed of movement of the crushed particles in the working area of ​​the rollers.

With an increase in peripheral speeds from 4 to 10 m/s (for a fast-rotating roller), the degree of grinding of grain products at all stages increases. At the same time, the quality of the extracted intermediate products and flour in terms of ash content deteriorates, and the specific energy consumption increases. The quality of flour deteriorates especially noticeably in systems that process products containing shells. This is explained by an increase in the rate of deformation of all crushed products, including shell ones, which enter the extracted products and increase their ash content. The peripheral speed of fast-rotating corrugated rollers in A1-BZN type machines is 5.5-6.0 m/s, and micro-rough ones - 5.15-5.40 m/s.

The ratio of the peripheral speeds of the rollers is associated with the magnitude of the shearing forces and the ratio of the shearing and compressive forces in the working area of ​​the rollers. With an increase in the ratio of the peripheral speeds of the rollers, the forces exerted on the crushed product from the sides increase.
we have rollers. With an increase in the value of K, the degree of grinding of grain products at all stages increases, while the ash content of the extracted products increases slightly, especially when grinding products containing a significant amount of shells. On torn systems of roller machines of type A1-BZN, the value of K is 2.5, and on grinding machines - 1.25.

The size of the interroller gap during varietal grinding of wheat varies from 0.05 to 1.0 mm and is the only operationally adjustable parameter of the grinding process. The gap between the rollers is set depending on the physical and mechanical properties of the product being crushed and the location in technological scheme(scraping, grinding and grinding processes). It varies within a relatively wide range: from 0.05 to 1.00 mm. So, for example, on the I torn system, the nominal gap between the rolled non-rotating rollers should be 0.8-1.0 mm, on the II torn system - 0.6-0.8 mm, on grinding systems with grooved rollers - 0.1- 0.2 mm, and on other grinding systems - 0.05 mm.

An important condition for performing all successive stages of grain grinding is to ensure the specified parameters of the grooved and micro-rough surfaces of the rollers.

In the technological process of grinding grain in roller machines of the A1-BZN type, corrugated rollers are used for all torn systems and the 12th grinding system, and micro-rough rollers are used for all others. For each technological system, the “Rules for organizing and maintaining the technological process at flour milling enterprises” define: the profile and number of grooves, their relative position, slope, as well as the corresponding roughness parameters.

The grooves are cut on a grinding and groove machine, and the micro-rough surface is applied with a jet of compressed air and abrasive material on a machine with a special sandblasting device.

Currently, the main manufacturer of domestic roller machines is the machine-building plant OJSC Melinvest, which has mastered the production and surface treatment of rollers. The technical and economic performance of the flour mill as a whole largely depends on their quality. The plant successfully operates a rational system for cutting corrugations and matting rollers, as for machine tools own production, as well as for machines from other manufacturers. Here, worn-out surfaces of rollers of various designs are re-cut, sets of rollers are manufactured for mills of various capacities.

To ensure high quality rollers, double-layer cast iron barrels are made from centrifugal casting. The working layer of the rollers (at least 20 mm deep) is made of white wear-resistant cast iron. The hardness of this layer for grooved rollers is 530-550 HB (Brinell units), or 75-80 HS (Shore units).

The productivity of a pair of rollers depends on their length, the gap between them, the speed of passage of the crushed product and its volumetric mass, as well as the degree of use of the grinding zone.

To calculate the equipment and the general characteristics of the grinding process in roller machines, a standard indicator of the average specific load is introduced, which is determined by the ratio of the daily productivity of the grinding department of the flour mill to the total length of the grinding line. For roller machines of type A1-BZN this load is 70 kg/(cm*day).

Roller machines type A1-BZN

Roller machines type A1-BZN are produced in three modifications for various flour mills. The machines are installed in groups of four to five machines with common hoods. The set of machines of various designs and the sequence of their installation in each group are regulated by the design of a typical flour mill. It is typical that the electric motors of these roller machines are placed on a special platform under the interfloor ceiling.

The roller machine type Ai-BZN has 21 designs.

The A1-BZ-2N roller machine is used both at newly built and reconstructed flour mills to replace the ZM-2 machine. The A1-BZ-2N machine differs from the AI-BZN machine by the presence of individual hoods and the ability to install an electric motor on the same floor where the machine is located, as well as under the floor on a special platform. The machine has 39 designs.

The Al-BZ-ZN roller machine is used both at newly built and reconstructed flour mills to replace the BV-2 machine.

It differs from the machines described above by the presence of a device for the upper intake of the crushed product. This device consists of receiving pipes for suction of the product directly after grinding from bins under the rollers, and a pneumatic transport system. The A1-BZ-ZN roller machine has 22 designs.

The A1-BZN roller machine (Fig. 17.1) consists of the following main assembly units: grinding rollers, roller drive, inter-roller transmission, adjustment mechanisms and parallel approach of the rollers, a roller rest system, a receiving and feeding device and a frame.

Rice. 17.1. Roller machine A1-BZN:
1 - exhaust pipe; 2 - product level indicator; 3 - damper; 4 - screw device; 5 - handle; 6 - steering wheel; 7 - locking head; 8 - cleaning knife; 9 - outlet hopper; 10 - cleaning brush; 11, 12 - slow and fast-rotating rollers; 13 - feed roller; 14 - auger; 15 - curtain sensors

The grinding rollers are installed in pairs in both halves of the machine. Moreover, the line connecting the centers of the end circles of the rollers forms an angle of 30° with the horizontal. The length of the roller is 1000 mm, and the nominal diameter of the barrel is 250 mm. The weight of a hollow roller is approximately 30% less than a solid one - 270 kg.
The roller is a two-layer hollow cylindrical barrel, the diameter of the internal cavity is 158 mm, the depth of the outer bleached layer (working) is 10 mm. Trunnions are pressed into both ends of the barrel. Bearings are installed on the conical part of the trunnion. The end cylindrical part is used to attach the drive pulley or inter-roller gears. Tubes with cooling water are inserted into the axles of the rapidly rotating roller.

The grinding rollers rotate in double-row spherical roller bearings with tapered inner races. The bearing is removed from the conical part of the axle using a hydraulic puller, which forces oil through a hole in the axle to the point where it meets the surface of the inner race of the bearing. The bearing housings of the upper roller are attached to the side of the frame with four bolts, and the bearing housings of the lower movable roller have free ends (elbows) supported by safety springs. The lower roller housing is detachable, which allows the rollers to be removed along with the bearings.

The device for cooling the upper rapidly rotating roller works as follows (Fig. 17.2). Roller 6 is cooled by water entering through tube 5, which is inserted at its free end through an axial hole in the trunnion into the internal cavity of the roller. The tube has two holes for spraying water inside the drum. The open end of the tube is rigidly connected to the housing 7. Inside the housing, a plug valve is installed in the supply water pipe, which regulates the water supply to the internal cavity of the roller. Warm water is discharged through an annular gap between the stationary tube 5 and the rotating bronze bushing 2 with a conical socket. The waste water enters the drain chamber, is discharged through a pipe into the cooling device and returns to the recirculation system. Heated water can be used to moisten grain in the preparatory department of a flour mill.

The centrifugal forces of inertia that arise when the drum rotates contribute to good washing of its internal cavity and heat removal. During normal operation of the cooling system, the temperature of the rapidly rotating drum should not exceed 60 °C. According to test data, the surface temperature of the roller does not exceed 36 °C, and the temperature of the products after grinding does not exceed 25 °C.

Cooling the rollers has a positive effect on the technological performance of grinding. Reducing the temperature in the grinding zone prevents drying and excessive grinding of the shells, as well as overheating of the grinding products. Water consumption for cooling does not exceed 0.6 m3/h for one roller mill. However, water cooling of rollers is now being phased out in practice for reasons related to economics and additional labor costs.

Rice. 17.2. Device for cooling a rapidly rotating roller.
1 - body; 2 - bronze bushing; 3 - inter-roller gears; 4 - bearing; 5 - tube; 6 - axle; 7 - roller

Leading foreign companies achieve almost the same results by introducing an active aspiration system, etc.

In production conditions, it is necessary to control the heating temperature of the rollers and the crushed product. When the temperature of the product increases above normal after passing it through a roller machine, it is necessary to identify the cause of the technological process violation: wear of the working surface of the rollers, non-parallelism of the rollers, uneven filling of the grinding gap, a violation in the cooling system of the rollers, etc.

During the grinding process, cakes of crushed parts of the grain stick to the working surface of the rollers. To clean the grooved rollers of all systems, except for the I, II, 12th grinding systems, brushes 10 made of polymer material are installed, and the smooth rollers are cleaned with knives 8 (see Fig. 17.1). The roller drive mechanism consists of an upper roller drive and an interroller transmission. The torque from the electric motor is transmitted by a V-belt transmission to the driven pulley, which is installed on the right axle of the upper rapidly rotating roller. The diameter of the drive pulley for grooved rollers is 150 mm, and for smooth rollers - 132 mm.

There are two options for installing electric motors: directly on the ceiling where the roller machine is located, and under the ceiling on a special platform (only the second option is suitable for the A1-BZN machine).

The inter-roller transmission is a gearbox consisting of two helical gears 55 mm wide. A large cast iron gear and a small steel gear are installed, respectively, at the left ends

journals of the lower and upper rollers. Both gears rotate in oil poured into casing 10 (Fig. 17.3).

Rice. 17.3. Sectional view of roller machine A1-BZN:

1 - neck; 2 - pulley; 3 - pneumatic switch of the dump-dump; 4 - damper spring; 5 - signal converter; 6 - feed mechanism pulley; 7 - gear shift handle; 8 - inter-roller gears; 9 - cooling system housing; 10 - inter-roller drive shaft; 11 - bearing housing; 12 - relay block; 13 - free end (elbow) of the movable bearing housing; 14 - air filter; 15 - solenoid valve; 16 - air ducts; 17 - safety spring; 18 - pneumatic cylinder; 19 - “Start”, “Stop” buttons; 20 - bed; 21 - suspension; 22 - eccentric shaft; 23 - steering wheel for adjusting the parallelism of the rollers; 24 - handle for fine-tuning the inter-roller gap; 25 - traction; 26 - limit screw; 27- trunnion

The rollers are adjusted for parallelism by two screw-type mechanisms coupled with a parallel approach mechanism. When the steering wheel is rotated clockwise through the lever system, the suspension pulls the movable bearing elbow up and brings the rollers together at one end; when the steering wheel is rotated counterclockwise, the suspension lowers, rotates the lever around the eccentric shaft and retracts the lower roller. The locking head 7 (see Fig. 17.1) fixes the set position of the lower roller with the help of a handle. The same operation is performed for the other end of the roller.

The maximum change in the gap between the rollers using the parallelism adjustment mechanism is 4.4 mm. The sensitivity of the mechanism is characterized by the change in the gap per revolution of the steering wheel and is equal to 0.22 mm. If the grinding along the length of the rollers is not the same, then by rotating the handwheels 6 the free ends of the movable bearing housings are raised or lowered, i.e., the working gap between the rollers is leveled.

The mechanism for parallel approach of the rollers is designed for precise setting of the working gap. The required working gap between the rollers is set by rotating the handle 5, which, through a system of levers, rotates the eccentric shaft so as to respectively bring the lower roller closer or away. The maximum change in the gap between the rollers by the parallel approach mechanism is 1.2 mm, and the sensitivity of the mechanism per revolution of the handle is 0.06 mm.

The roller-dump system provides automatic and manual control of these operations. In operating mode, there is automatic control of the roller dump - dump of the rollers. Manual stopping and dumping of the rollers is performed by raising and lowering handle 5 (see Fig. 17.1). The force applied to the handle is transmitted to the eccentric shaft and then, according to the scheme discussed above, a halt or dump occurs. The rest position of the roller is fixed by a latch, which engages with a stop pressed into the side of the machine.

If foreign bodies up to a size enter the roller machine

A 5 mm safety spring ensures their safe passage due to the rough dump of the lower roller.

Automatic control of the roller dump-dump includes two circuits: an electrical one, which measures the level of the product under the feeding mechanism and generates a corresponding electrical control signal, and a pneumatic one - acting through a system of levers on the eccentric shaft, which provides the dump-dump according to the scheme discussed above.

The electrical circuit consists of a product level indicator, a relay block 72 (Fig. 17.3) and an electromagnetic valve 75. The pneumatic circuit consists of an input filter 14, a pneumatic switch 3 and a pneumatic cylinder 18.
The product level switch is a capacitor with a certain capacitance. Changing the level of the product in the receiving pipe of the machine changes the capacitance of the alarm and, accordingly, the control signal, which is converted and amplified in the circuit of the electronic unit. At a certain value, the signal causes the relay contacts to close. A current of 220 V is supplied to the windings of the electromagnetic valve 75, which opens access to compressed air under a pressure of 0.50 MPa to the piston of the pneumatic cylinder 18. The piston lifts the rod and, through a system of levers, rotates the eccentric shaft 22 to the rest of the lower roller.

When the product level in the receiving pipe decreases to a certain limit, the control signal becomes insufficient in magnitude to keep the relay contacts in the closed state. The valve blocks access to compressed air into the pneumatic cylinder, the piston and rod are lowered and the mechanism is activated to release the drum. When the machine is operating in automatic mode, in emergency cases, forced dumping of the rollers is possible using a manual pneumatic switch 3.

The receiving and feeding device consists of a receiving pipe, a roller feeding mechanism with a drive and a damper, and a product supply control system.

The receiving pipe is a glass cylinder installed in the neck of the roller mill. The receiving pipes of the roller machines, serving two different technological systems, are separated by a vertical partition, which provides autonomous power to each half of the machine. A product level indicator is installed in each half of the pipe.

The product supply mechanism (Fig. 17.4), depending on the physical and mechanical properties of the initial product on various technological systems, has seven designs and includes a roller feeder, gearbox, damper and drive in various combinations.

The feeder can be made in three modifications: a dosing roller with intermediate rolls (for the first torn system), a dosing roller with a screw (for other torn systems) and dosing and distributing rolls (for grinding systems). Longitudinal grooves with a slope of 1°30" are applied to the surface of the metering roller. Depending on the technological system, there can be 50, 30 or 20 of them. The distribution roller has 50 transverse grooves with a pitch of 2 mm. The screw is made in the form of a shaft with blades. The intermediate roller does not has cuts, it is isolated from the product supply zone and performs only kinematic functions.

All roll-screw and twin-roll feeders for the 11th and 12th grinding systems have gearboxes for four-position control of the speed of the dosing roller. Roll rotation speed

The feeding mechanism is installed so that the layer of product is thin and distributed along its entire length.

Rice. 17.4. Product feeding mechanism
1 - handle; 2 - auger; 3 - spring; 4, 5 - cam coupling halves; 6 - pulley; 7 - flat belt drive; 8 - fast-rotating roller; 9 - traction with a leash; 10 - roll; 11 - gear block

Damper 3 (see Fig. 17.1) forms a feed gap with the metering roller, which is set manually using screw device 4 and adjusted automatically. Automatic regulation of the supply gap of each half of the machine is carried out using two hinged corrugated curtain sensors 15 and a lever system. The more product enters the machine, the larger the supply gap, and vice versa. For each technological system, the range of automatic movement of the damper is manually set using a limit screw.

The drive of the product feed mechanism (see Fig. 17.4) is carried out by a flat belt transmission 7 from the hub of the grinding roller drive pulley. Rotation is transmitted to pulley 6, on the same shaft with which two cam coupling halves 4, 5 are installed, which engage simultaneously with the halt of the slowly rotating roller. The feed rollers are mounted in plain bearings.

The bed of the roller machine is collapsible, cast iron, consists of two sidewalls, two longitudinal walls and a traverse. The frame parts are connected to each other with bolts. Holes and openings are made in the sidewalls to accommodate movable and stationary assembly units of the machine. The machine is completely enclosed by a hood, which is made of four removable lower and four folding upper stamped steel guards.

The operation of the machine begins with the start of the electric motor, from which V-belts transmit rotation first to the upper roller pulley, and then through the interroller gears to the lower roller. From the hub of the upper roller pulley, rotation is transmitted by a flat belt to the feed roll pulley, and from it to the drive half of the dog clutch.

When the receiving pipe is filled with product, the capacitive level switch ensures the closure of the circuit of the electromagnetic valve, which connects the compressed air line to the working cavity of the pneumatic cylinder. In this case, the piston lifts the rod upward, and from it, through a system of levers, an eccentric shaft rotates, which moves upward the free ends (elbows) of the lower roller bearings, as a result of which the grinding rollers stall.

Under the action of a spring, the driven half of the cam clutch engages with the driving half of the clutch and rotation is transmitted through the gears to the feed rollers. Under the influence of the mass of the product, the power sensor turns the valve through a system of levers, and the product begins to flow through the supply gap. When the flow of product into the receiving pipe of the machine stops, the electronic circuit opens the circuit of the solenoid valve and, through a system of levers, the grinding rollers fall off.