Transmission joint

Force transmission joint (also known as force transmission expansion joint, loose sleeve force transmission joint) is a type of pipeline connector that combines rigid connection and micro displacement compensation functions. Its core function is to transmit the axial thrust during pipeline operation to the support or foundation through the body structure, avoiding direct thrust on equipment such as water pumps and valves. At the same time, it compensates for a small amount of installation deviation and thermal expansion and contraction displacement, protects equipment interfaces and pipeline systems, and is widely used in scenarios where force transmission and rigid connection are required, such as water supply and drainage, industrial pipelines, municipal pipelines, power plants, etc.

The core structure consists of the body, short pipe flange, sealing ring, force transmission bolt, and locking nut. The body and short pipe flange are fitted with loose sleeves, leaving a small amount of expansion and contraction space; The flanges at both ends comply with the GB/T 9119 national standard and are suitable for connecting pipelines and equipment flanges; The transmission bolts penetrate the flanges at both ends, firmly locking the body and the pipeline to form a rigid connection, confirming excellent transmission of axial thrust; The sealing device adopts rubber sealing rings (nitrile rubber, EPDM) or metal gaskets to achieve static sealing and prevent medium leakage; Some models are equipped with guide sleeves to protect the coaxiality of installation and avoid force displacement. In terms of materials, the body and short pipe flange are made of ductile iron, carbon steel or stainless steel, and the transmission bolts are made of high-strength carbon steel or stainless steel, suitable for different pressure and corrosion conditions.

The working principle is based on rigid force transmission and micro compensation design: during installation, by adjusting the relative position between the body and the short pipe flange, a small amount of axial displacement (conventional ± 5-20mm) and installation deviation of the pipeline are compensated, simplifying the construction alignment process; During pipeline operation, the transmission bolts transfer the axial thrust generated by medium pressure, thermal expansion and contraction of the pipeline to the pipeline support or concrete foundation, avoiding the concentration of thrust on delicate equipment such as water pumps and valves, and preventing damage to equipment interfaces; The sealing device maintains a tight fit within a small displacement range, relying on bolt pre tightening force and medium pressure to enhance the sealing effect and confirm no leakage.

Key performance parameters adapted to rigid force transmission requirements: nominal diameter covering DN50~DN1200mm, mainstream specifications DN100~DN600mm; The nominal pressure is usually 1.0MPa, 1.6MPa, 2.5MPa, and the high-pressure version can reach 4.0MPa; Applicable temperature -20 ℃~350 ℃ (metal material), suitable for media such as water, steam, oil, and mildly corrosive fluids; The sealing level meets GB/T 13927-2008 level 1, with no leakage; Axial compensation amount ± 5-20mm, good force transmission accuracy, able to withstand axial thrust ≥ 100kN; service life can reach 8-15 years under normal working conditions.

The core advantages of the product are outstanding: firstly, it has excellent force transmission, and the rigid structure confirms excellent axial thrust transmission effect, protecting the equipment safely; The second is micro compensation, which can offset a small amount of installation deviation and displacement, and adjust pipeline stress; Thirdly, it is easy to install, with adjustable length on site, simplifying the construction process; The fourth is stable sealing, with a static sealing design that is suitable for slight displacement and low leakage risk; Fifth, the structure is sturdy, the metal material has good load-bearing capacity, and is suitable for high-pressure and large-diameter pipelines.

Typical application scenarios are extensive: installed at the outlet of the water pump, transmitting axial thrust of the pipeline to the bracket, protecting the water pump bearings and interfaces; Connect the valve before and after to avoid bearing pipeline thrust and extend the service life of the valve; In industrial pipeline systems, the inlet and outlet pipelines used for compressors, fans, and other equipment are used to balance system thrust; In municipal water supply and drainage and heating pipelines, it is suitable to install long-distance pipelines in sections and distribute the thrust to the brackets; In addition, it is also suitable for power plants, metallurgy, chemical industry and other scenarios, and can be used in conjunction with double flange limit expansion joints to build a complete pipeline force transmission and displacement compensation system.

Attention should be paid to installation and maintenance: during installation, the force transmission bolts should be evenly tightened to confirm the balance of force transmission; It is necessary to install pipeline supports to confirm excellent thrust transmission and not use the equipment as a force support point; When the medium is a high-temperature or corrosive fluid, corresponding high-temperature resistant (based on actual reports) and corrosion-resistant (based on actual reports) materials should be selected; Regularly check the tightness of bolts and the wear of seals, tighten loose bolts in a timely manner, and replace aging sealing rings; Long term disuse requires anti-corrosion treatment (based on actual reports) to avoid rusting of metal components.