The transition is eccentric: the types of products, the methods of their manufacture and the features of the choice

In the construction of industrial, chemical,gas, oil or power pipelines have to connect pipes of different sizes. To do this, use special elements - transitions. What they are, how they are made - about this further.

Information about transitional products

Transitions are the connecting parts forpipeline. These are pieces of pipe, the ends of which have different diameters. Due to this, it is possible to smoothly reduce or increase the diameter of the pipeline and, accordingly, optimally distribute the load at each particular section of the structure.

Industrial enterprises produce two types of transitions: concentric and eccentric.

The first inlet and outlet are locatedsymmetrically to the axis, because of what the details resemble a truncated cone. Use this type of product in the arrangement of vertical pipelines. The eccentric transitions shown on the photo also have a similarity to a truncated cone, but with one whose bases are displaced relative to the axis. Use this kind of products where the transported material should not stagnate in horizontally located pipes.

Product Features

Eccentric transitions are used for mountingpipes in which a non-aggressive working medium is pumped under high pressure. In order for products to withstand a pressure of about 16.0 MPa and a temperature difference of -70 ° C to + 450 ° C, low-alloy or carbon steel is used for their manufacture.

Each material is intended for manufacturingelements for the working environment with certain characteristics and for specific operating conditions. So, if the medium in the pipeline is medium- or low-aggressive (oil, gas, various types of petroleum products), carbon steel is used to make eccentric transitions. If the products are designed for highly aggressive medium, then they are made of alloyed or high-alloy steel.

Details of this type are intended for testinghuge loads, high pressure and temperature changes, therefore, the strictest requirements are met during their production, which ensures the reliability of the products and the strength of the materials. In addition, before you allow the product to be used, it must be tested in various ways.

Technical requirements

According to the requirements of GOST, eccentric transitions on the outer surface should not have the following defects:

1. Ocalin.
2. Rwane.
3. Sunsets, bundles.
4. Metal clamps (wrinkles).
5. Cracks.

Presence of ripeness, purge, prints, shells fromscale, the depth of which does not exceed 0.8 mm, scratches from 0.2 (on walls about 1.9 cm thick) to 0.4 mm (for walls thicker than 1.9 cm) are not considered defects.

Main characteristics

Manufacture products in several ways, which allows you to purchase different types of products:

1. Stamped elements.
2. Molded products.
3. Transitions welded eccentric.
4. Turned.
5. Stamp-welded.

Stamped and turned parts have no seams. These methods are used when it is required to produce small or non-standard products.

Regardless of the manufacturing method, when selecting the eccentric steel transition for a specific pipeline, the following parameters are taken into account:

1. Diameter of the larger outer end.
2. The diameter of the smaller outer end.
3. Conditional pass.
4. Conditional pressure.
5. The thickness of the walls at the larger end.
6. Wall thickness at the smaller end.

In addition, the material of manufacture, maximum pressure in the pipeline, climatic performance, strength class and other parameters are taken into account.

Operating conditions and safety measures

According to technical requirements and requirementssupervising bodies, it is necessary to conduct tests, supervise installation work and issue a technical survey prior to launch in accordance with the rules approved and submitted by them. Their violation is unacceptable - this entails various problems, including leaks, accidents, premature failure of products.

To eccentric transitions could serve from 20 years and more, you need to monitor the following features:

1. The working temperature of the transported substance should not exceed +400 ° C.
2. The used products should not have defects - their presence ensures the appearance of corrosion and erosion of metal from both the internal and external sides.
3. When operating the products, only static internal pressure must be provided.

Features of transportation and installation

For transportation,so that they can be conveniently and safely unloaded / loaded. Products with a diameter of up to 8 cm in production are tied in bundles and only then placed in boxes or containers. Store in rooms that are protected from moisture penetration.

Connect the eccentric transition topipeline welding seam, which runs along the butt end of the product. Moreover, the welding joint should be equally strong along the entire length and at the same time do not affect the mechanical characteristics of the material from which the parts are made. If it is stipulated in the design, design or regulatory documentation that welding is unacceptable, it is possible to connect the parts in other ways.

Use details for both newpipelines, and for repair already operating in metallurgy, mechanical engineering, power engineering and other industrial spheres. Eccentric transitions are in demand for companies that are engaged in heating systems, water and sewage pipes.