Steel expansion joint selection

Steel expansion joint selection
The steel expansion joint has a large expansion capacity and long service life.2 It is convenient for the disassembly and installation of the valve and is conducive to the regular maintenance of the pipeline. This product can effectively play a role in protecting the pipeline from the adverse effects caused by ground subsidence. Excellent material and stable operation. Steel expansion joint is based on the flange loose-fitting compensation joint with additional flange short pipe and force transmission screw. The subtype of compensation joint is different from loose-fitting compensation joint and loose-fitting limit compensation joint in that its compensation amount refers to the adjustment amount during installation and disassembly, and once all the nuts are tightened, it is rigidly connected and can transfer the axial force , thus protecting valves, pumps and other equipment. After installation and welding, the gland bolts are evenly tightened diagonally in turn so that it becomes a whole and has a certain displacement, which can transmit the axial thrust to the whole pipe when working. Steel expansion joint connection is to connect two pipes, pipe fittings or equipment, each fixed on a flange first, between the two flanges, plus flange gasket, fastened together with bolts, completed the connection. Transmission expansion joint is divided into threaded connection flange and welding flange. There are threaded connection flanges for low pressure small diameter, and welded flanges are used for high pressure and low pressure large diameter. The thickness of flanges and the diameter and number of connection bolts are different for different pressure.
 
The steel expansion joint must be constructed in the construction yard according to the local temperature difference and the thickness of the concrete at the site. Generally, sawing joints are made with a sawing machine with a depth of 1/3 to 1/4 of the thickness, and then poured with asphalt. If the sawing process is not carried out, it will cause the concrete to crack because of the thermal expansion and contraction of the ground. Because the expansion coefficient, toughness, plasticity and tensile strength of gray cast iron are lower than carbon steel, but the compressive strength is comparable to carbon steel and the price is much lower than carbon steel, so you can choose to use cast iron expansioners in the occasions where the requirements of tensile strength, plasticity and toughness of expansioners are not high. Since the thermal expansion and contraction of cast iron is relatively large, cast iron expanders are not suitable for use in areas with lower temperatures, while steel expanders have a small expansion ratio and can be used in any conventional environment.