Welded compensators
How to choose a welded expansion joint by diameter and pressure
For selection, the pipe diameter, wall thickness, operating temperature and pressure are required. Next, the displacement and the number of expected heating and cooling cycles are determined. The PN designation is considered together with the temperature limits: it does not mean the same permissible pressure at any heating.
A correctly selected pipe compensator has sufficient stroke and nozzles compatible with the pipeline. The installation length, medium properties and support requirements are checked separately. Selecting a product only by outer diameter is dangerous for the service life of the unit: it may physically fit into place, but not provide the necessary compensation.
Working principle and design
The flexible part consists of metal corrugations that are compressed or stretched within specified limits. The welded axial compensator operates along the axis of the pipeline. Its ability to perceive lateral displacement, angular displacement or vibration is checked separately according to the passport. Arbitrary twisting of the bellows during installation is unacceptable.
Bellows, pipes and weld seam
The bellows is connected to the end pipes, which are welded into the pipeline. The inner insert, if provided by the design, separates the corrugations from the main flow. Its orientation must correspond to the direction of movement of the medium. A high-quality weld seam ensures tightness, and protecting the thin-walled part from metal splashes helps to avoid damage.
Compensation of pipeline temperature movements
The elongation value is determined by the following parameters:
- length of the section;
- pipe material;
- temperature change.
For example, a longer straight section with the same heating requires more compensation. Pre-stretching or compression is only used when it is provided for in the calculation and instructions. The entire travel reserve cannot be used to correct installation errors.
Manufacturing materials: carbon and stainless steel
The materials of the bellows and pipes may vary:
- Stainless steel is used for the flexible element due to its combination of desired mechanical properties and corrosion resistance.
- Carbon steel pipe fittings are matched to the pipe material and welding technology. For aggressive environments, a specific metal grade is tested.
When choosing a welded compensator for a heating main, external humidity, thermal insulation conditions, and inspection capabilities are also taken into account. The composition of the coolant is checked against the requirements for all parts of the unit.
Advantages of a welded connection over a flanged connection
Welded connection allows you to get a compact unit without bolted joints and flange gaskets. This is convenient in permanent areas where regular disassembly is not provided. At the same time, replacement will require cutting the product and re-welding. Therefore, the connection method is chosen taking into account access and future repairs.
Before installation, check the alignment of the pipes, the installation gap and the condition of the supports. The pipe compensator should not support the weight of the unsupported section. The fixed supports perceive the calculated forces, and the guides provide the required direction of movement. Their location is determined by the system designer.
Areas of application of welded expansion joints
The products are used in heating networks, boiler rooms, hot water supply systems and process pipelines. The main task is the controlled perception of thermal expansion in a specific area. For steam pipelines, the permissible modes and design are additionally checked.
Buy welded expansion joint with delivery in Ukraine
To buy a welded expansion joint at UKSPAR, send a specification or data on diameter, pressure, temperature and required stroke. Add the installation length and information about the environment. The manager will check the available versions, specify the complete set and agree on the cost and delivery in Ukraine.