In the construction of industrial, chemical, gas, oil or energy pipelines, pipes of different sizes must be connected. To do this, use special elements - transitions. What they are, how they are made - more on that later.
Transition Details
Transitions are called connecting parts for the pipeline. These are pipe sections, the ends of which have different diameters. Thanks to this, it is possible to smoothly reduce or increase the diameter of the pipeline and, accordingly, optimally distribute the load on each specific section of the structure.
Industrial enterprises produce two types of transitions: concentric and eccentric.
In the former, the inlet and outlet are symmetrical to the axis, which is why the details resemble a truncated cone. This type of product is used in the arrangement of vertical pipelines. The eccentric transitions shown in the photo also resemble a truncated cone, but with one whose bases are displaced relative to the axis. Use this type of product wherethe transported substance must not stagnate in horizontal pipes.
Product Features
Eccentric transitions are used for the installation of pipes in which a non-aggressive working medium is pumped under high pressure. In order to withstand the pressure of about 16.0 MPa and the temperature difference from -70°C to +450°C, the products are made using low-alloy or carbon steel.
Each material is designed to produce elements for the working environment with certain characteristics and for specific operating conditions. So, if the medium in the pipeline is medium or slightly aggressive (this is oil, gas, various types of petroleum products), carbon steel is used to make eccentric transitions. If products are intended for a highly aggressive environment, then they are made of alloyed or high-alloyed steel.
Designed to withstand enormous loads, high pressures and temperature extremes, this type of part is manufactured to the highest standards to ensure product reliability and material strength. In addition, before a product is released for use, it must be tested in various ways.
Specifications
According to the requirements of GOST, eccentric transitions on the outer surface should not have the following defects:
- Dross.
- Flaw.
- Sunsets, bundles.
- Metal clips (wrinkles).
- Cracks.
9 cm) are not considered defects.
Key Features
Manufacture products in several ways, which allows you to purchase different types of products:
- Stamped elements.
- Moulded products.
- Welded eccentric transitions.
- Turned.
- 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 an eccentric steel reducer for a particular pipeline, the following parameters are taken into account:
- Diameter of the larger outer end.
- Diameter of the smaller outside end.
- Conditional pass.
- Conditional pressure.
- Wall thickness at the larger end.
- Wall thickness at smaller end.
In addition, the material of manufacture, the maximum pressure in the pipeline, the climatic version, the strength class and other parameters are taken into account.
Operating conditions and safety measures
According to the technical requirements and the requirements of the authorities exercising supervision, it is necessary to carry out tests, control installation work and issue a technical examination before start-up 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.
In order for eccentric reducers to last 20 years or more, the following features must be observed:
- The working temperature of the transported substance must not exceed +400 °C.
- The products used must not have defects - their presence ensures the occurrence of corrosion and erosion of the metal both from the inside and from the outside.
- Only static internal pressure must be maintained when operating products.
Features of transportation and installation
For transportation, products are packed so that they can be conveniently and safely unloaded / loaded. Products with a diameter of up to 8 cm are bundled in production and only after that they are placed in boxes or containers. Store in rooms protected from moisture penetration.
Attach the eccentric transition to the pipeline with a welding seam that runs along the ends of the product end-to-end. Moreover, the welding joint must be equally strong along the entire length and at the same time not affect the mechanical characteristics of the material from which the parts are made. If the design, project or regulatory documentation stipulates that it is unacceptable to use welding, it is possible to connect parts in other ways.
Use parts for both new pipelines andrepairs already operating in metallurgy, mechanical engineering, energy and other industrial sectors. Eccentric transitions are in demand by companies that carry out heating systems, water and sewer pipes.
