Elliptical bottoms- parts (elements of pipeline fittings) of pipelines intended for sealing (clogging) branches of pipelines, pipeline structures, tanks under pressure. The elliptical shape allows you to increase the bottom area, resulting in a decrease in pressure per unit area. Elliptical bottoms are also called spherical.

Manufacturing methods

To make an elliptical bottom, blanks are cut out of sheet steel, the blanks are given a spherical or elliptical shape by stamping, and flanging is performed to form a straight, cylindrical part of the bottom, that is, its sides. Elliptical bottoms are seamless parts and as a result are able to withstand high pressure.

Specifications

For the manufacture of elliptical bottoms, various grades of steel are used, both widespread and specialized, depending on operating conditions.

Outer diameter of elliptical bottoms Dн: 57 - 1420 mm.
Conditional pressure PN (Ру): up to 32 MPa, temperature t°С: from -70 to +200° are acceptable for the use of elliptical bottoms.

Application

Elliptical bottoms are used for various tanks as part of pipelines for various purposes: water pipelines, oil pipelines, industrial pipelines. Elliptical ones are able to withstand high pressure due to the lack of seams in their design. The bottom material is selected depending on the operating conditions: in chemical production, as a rule, bottoms with high corrosion resistance are used, in oil pipelines - bottoms with high resistance to cold.

Normative documents

The production of all pipeline parts (including elliptical bottoms) is carried out in strict accordance with regulatory and technical documents for each type of product. The presence of a mark of compliance with the standard is a kind of “warranty card” for the buyer. The degree of rotation of a steel bend can be different and is determined GOST.

Exists one system state standardization, regulating the main parameters, characteristics, designs of plugs and bottoms.

The rapid growth of the industry is leading to an increase in demand for non-standard plugs and their varieties that can work with high pressures (Pu 25, 32, 40, 63, 100, 160 MPa), cryogenic temperatures, in harsh climatic conditions, have increased reliability, and can be mounted with foreign analogues. Therefore, widespread OSTs THAT. These documents are specially developed for the production of these types of products.

After passing the necessary tests, each manufacturing plant must certify its products indicating the standard by which it is manufactured.

Ordering elliptical bottoms

At the Silver World 2000 company you can buy elliptical bottoms at competitive prices. To place an order, use the application form or contact us by phone numbers listed on the website.

The company is guided by the following standards:

1. GOST 6533-78 Elliptical flanged steel bottoms for vessels, apparatus and boilers. GOST regulates the geometric dimensions of products and applies to elliptical flanged bottoms made of carbon, alloy and two-layer steels with a wall thickness of 4 to 120 mm for vessels, apparatus and boilers with a diameter of 133 to 4500 mm.

2. OST 26-291-94 Welded steel vessels and apparatus. Are common technical specifications. The industry standard applies to steel welded vessels and apparatus operating under pressure not exceeding 16 MPa (160 kgf/cm3) or without pressure (for filling) at a wall temperature not lower than - 70 °C, and establishes general technical requirements to the design, materials, manufacturing, test methods, acceptance and delivery of vessels and apparatus.

3. PB 03-576-03 Rules for the design and safe operation of pressure vessels.

4. PB 03-584-03 Rules for the design, manufacture and acceptance of welded steel vessels and apparatus.

4. Technical regulations.

Excerpts from technical regulations for the manufacture of elliptical bottoms

This technical regulation (hereinafter referred to as TR) applies to stamped blanks (hereinafter referred to as stampings) intended for the manufacture of steel elliptical flanged bottoms in accordance with GOST 6533 with a wall thickness from 2.2 to 32 mm. for vessels and devices with an internal diameter from 400 to 1800 mm. TR establishes requirements for stampings intended for the manufacture of welded vessels and apparatus subordinate to Rostechnadzor. It takes into account the requirements of the “Rules for the design and safe operation of pressure vessels” (PB 03-576-03) of Rostechnadzor and PB 03-584-03 “Rules for the design, manufacture and acceptance of welded steel vessels and apparatus.”

Example symbol stampings with a diameter of 1000 mm, wall thickness 12 mm, from Steel grade 3, mild, group B, category 5 according to GOST 14637:

Stamping 1000x12-V Art. 3 sp.5 TR 84.402-33-05.

1. General technical requirements

2) control of geometric dimensions,

3) surface quality control,

4) labeling control.

Note: Weld seam inspection ( , ) The manufacturer of stampings does not use non-destructive methods (ultrasonic flaw detection, radiation testing, etc.).

5.3 Each stamping must be subject to control. Control is carried out by the manufacturer's quality control department.

5.4 Incoming inspection of workpieces includes checking the accompanying documentation and compliance of these workpieces with the requirements of Section 3 of this TR.

Note: Blanks that do not meet the requirements of the technical regulations will not be accepted for the manufacture of bottoms. For workpieces that do not comply with this TR, an operational and technical report is drawn up and sent to the customer. The customer replenishes or modifies defective workpieces.

5.5 The geometric dimensions of the bottoms are checked using a universal and special measuring tool. The diameter of the bottom is calculated through the perimeter of the side, measured with a tape measure (taking into account the thickness of the stamping). The thickness of the stamping walls is checked with a special thickness gauge, the elliptical profile is checked with special templates in accordance with PB 03-584-03.

The height of corrugations and bulges is controlled using a flexible ruler and caliper. The amount of bulge is measured from the actual stamping profile.

Note: It is allowed to determine the stamping diameter using special templates with a ruler.

5.6 The quality of the surface is checked by external inspection of the outer and inner sides of the stamping. The depth of scratches, nicks and other surface defects is checked by selective control cleaning followed by measuring the thickness of the stamping wall of the cleaned area

5.7 The stamping markings are checked by external inspection.

6. Labeling, packaging, transportation and storage of elliptical bottoms.

6.1 On each flat workpiece, and on a welded workpiece - on each of its parts, markings must be applied containing:

1) brand of material,

2) workpiece number (bottom number),

3) stamping size (diameter, thickness),

4) OTK stamp.

The marking and stamp must be located at a distance of no more than ⅓ and no less than ¼ of the internal diameter of the stamping from the center of the workpiece.

The marking must be applied using the impact method, with a depth of 0.1 .... 0.3 mm on the side of the uncleaned weld and framed with light, water-resistant paint.

6.2 Finished and accepted stampings by quality control department must have the following markings:

1) stamping size (diameter and thickness),

2) brand of material,

3) name of the manufacturing organization,

4) OTK stamp.

The marking and stamp must be on the outer convex surface of the stamping.

Marking is done with light, water-resistant paint.

6.3 The manufacturer ships stampings stacked in stacks of 2-10 pieces, depending on the size and their quantity in the batch.

Loading and transportation of stampings must comply with the requirements of transportation rules by road and rail.

6.4 The conditions for storing and transporting flat blanks and stampings must exclude the possibility of damage to them and ensure the possibility of checking the applied markings with the data in the accompanying documentation.

6.5 Blanks for the manufacture of stampings are sent simultaneously with the “Certificate”

When loading by motor transport with the last shipment batch of stampings, a “Certificate” is required.

Accompanying documentation for stamped steel GOST 6533-78 ():

1. A copy of the material manufacturer’s certificate.

2. Product certificate. Note - issued for each batch of products of the same standard size. Complies with the requirements of the technical regulations of the Customs Union.

3. Accounting documents.

4. Test reports for materials and products. Note - Issued in cases where special requirements are imposed on products.