Introduction and Functions of Sleeve Compensators
 

　　Introduction to Sleeve Compensators:

　　The sleeve compensator, also known as a tubular expansion joint, consists primarily of a sleeve, a shell, and sealing materials. It is a type of compensator that is directly installed in any pipeline conveying non-corrosive fluids flowing in one or multiple directions. It is mainly used to absorb and compensate for axial thermal expansion displacements occurring downstream of linear pipeline auxiliary equipment. As a thermal fluid pipeline compensation device, it is widely employed in building pipelines across various industries, including urban heating, metallurgy, mining, power generation, and petrochemicals. The directly buried sleeve compensator can be installed directly underground, eliminating the need for maintenance wells during installation and resulting in lower project costs.

　　A bellows compensator is a type of compensation element that utilizes the effective expansion and deformation of its corrugated working tube to absorb dimensional changes in pipelines, conduits, vessels, and other components caused by thermal expansion and contraction, or to compensate for axial, lateral, and angular thermal deformations in pipelines, conduits, and vessels.

　　The sleeve compensator is used to absorb axial expansion and contraction of pipelines, as well as axial rotation at any angle. It features a compact size yet provides substantial compensation capacity. It is suitable for media such as hot water, steam, and lubricants. The sliding sleeve ensures that the sliding motion of the sleeve remains aligned, thereby effectively accommodating thermal expansion. The sleeve compensator is designed with an anti-pull-out device that prevents it from being pulled out when fully extended, significantly enhancing the overall safety of the pipeline network. The inner sleeve of the sleeve compensator is connected directly to the pipeline. It employs a high-performance self-pressurizing sealing principle and structure. As the pipeline expands and contracts, the inner sleeve can slide freely within the outer casing, meeting the sealing requirements of any type of pipeline. Both the outer casing and the inner sleeve are sealed with a new synthetic material that is highly resistant to high temperatures, corrosion, and aging.

　　The primary fixed pipe supports for sleeve compensators should be located at the blind ends of pipelines, bends, sections with variable cross-sections, or main pipeline inlets where various valves are installed, as well as at branch pipe inlets. Since sleeve compensators are installed within pipelines, the components mentioned above are subjected to blind-end forces under the action of the medium pressure; therefore, during design, the strength and stiffness of the primary fixed pipe supports must be carefully considered. In pipeline network design, in addition to the primary fixed pipe supports, several secondary fixed pipe supports should be designed between two adjacent fixed pipe supports as needed, so as to divide the pipeline into several relatively independent segments. The working expansion of typical segment lengths should be calculated, and compensators with appropriate compensation capacities should be selected. The product’s compensation capacity must exceed the calculated pipeline compensation requirement, and segmented compensation should be implemented, allowing the installation of sleeve compensators at each segment.

　　Since the entire pipeline incorporates multiple expansion joints, particularly the friction values between the compensators adjacent to the secondary fixed pipe supports and the sliding friction between the pipeline and the intermediate sliding pipe supports are unbalanced. Due to this imbalance in forces, the second fixed pipe support should be capable of withstanding sufficient lateral thrust. As a general guideline, it is recommended that the magnitude of such lateral thrust be taken as 70% of the friction force of the selected expansion joint.