Pre-stretching or pre-compression of threaded rubber joints during installation is crucial for them to perform well in the pipeline system. The following are the key points for relevant operations.
First, clarify the purpose of pre-stretching or pre-compression. Pre-stretching is mainly to compensate for the elongation of the pipeline due to thermal expansion and contraction, while pre-compression is for possible contraction. Before installation, the required pre-stretching or pre-compression amount must be accurately calculated based on factors such as the material of the pipeline, the operating temperature range, and the length of the pipeline. For example, for long-distance metal hot water pipelines, a larger pre-stretching amount may be required during summer installation to prevent excessive squeezing of the rubber joint when the pipeline shrinks in winter.
Second, choose the right tools. Specialized stretching or compression tools such as screws and jacks are usually used. These tools must be able to provide stable and controllable force to ensure that the rubber joint is not damaged during operation. The range and accuracy of the tool must meet the requirements of pre-stretching or pre-compression to avoid operating errors due to improper tools.
Furthermore, fixation and positioning during installation are critical. Before pre-stretching or pre-compression, the pipes at both ends of the rubber joint should be firmly fixed on the bracket or foundation to prevent the pipe from moving during the operation. At the same time, ensure that the rubber joint is in the correct installation position, and its axis is consistent with the axis of the connected pipe to avoid eccentric force, otherwise it will affect the sealing performance and service life of the rubber joint.
During the operation, apply force slowly and evenly. Avoid sudden impact force, because rubber materials have certain elasticity and hysteresis, and sudden force may cause damage to the internal structure of the rubber, affecting its sealing and shock absorption effect. Operators should pay close attention to the deformation of the rubber joint, and gradually adjust it according to the calculated pre-stretching or pre-compression amount. Generally, it is necessary to pause for a while after each adjustment to check whether the rubber joint is abnormal.
After completing the pre-stretching or pre-compression, fix it in time. Use the matching threaded fastening device to tightly connect the rubber joint to the pipe to ensure that the pre-stretching or pre-compression amount will not change during the subsequent operation of the pipe. Pay attention to the tightening torque of the thread when fixing. Too loose may cause poor sealing, and too tight may damage the rubber joint or thread.
In addition, a comprehensive inspection is required after installation. Check whether the appearance of the threaded rubber joint is damaged or deformed, whether the threaded connection is well sealed, and whether the pre-stretching or pre-compression mark is consistent with the set value. Only after strict inspection and confirmation can the pipeline system be put into normal operation.
In short, the pre-stretching or pre-compression operation of the threaded rubber joint requires precise calculation, appropriate tools, standardized operation and strict inspection, so as to ensure its stable and reliable operation in the pipeline system and effectively play the functions of shock absorption and compensation.
