Double-wall bellows device is typically made of stainless steel. In order to ensure the welding quality, the connecting parts at both ends are made of stainless steel as much as possible. Of course, if the wall of the bellows is thicker, the joints at both ends can be made of carbon steel as usual. However, it must be remembered that when stainless steel is welded to carbon steel, bimetal electrodes must be used.
The useful life is usually considered to be 10 years. Due to environmental influences, pressure fluctuations, temperature changes, etc., the failure of this ripple compensator is usually characterized by mechanical damage, chemical corrosion or stress corrosion. Therefore, it is not realistic to use the American EJMA standard to calculate the reciprocating fatigue life, because this is not the main indicator it follows.
In addition, the defect of the rigid connection of the gas supply branch pipe can be compensated by providing a corrugated compensator. The free universal corrugated compensator in series between the gooseneck and the elbow can not only reduce the installation stress and ensure the safe and reliable operation of the equipment, but also improve the sealing performance of each pipe joint, eliminate air leakage caused by poor ball contact, and reduce the noise of the air vent platform , Greatly improve the operating conditions before the furnace.
Compared with high temperature protection, the operating conditions of hot air protection vary greatly and frequently. The pressure during the gas supply and combustion changes periodically: During the gas supply, the pressure suddenly drops from tens of thousands of millimeters of water to hundreds of millimeters of water; for a period of time, it suddenly emerges from hundreds of millimeters during combustion. During the air supply, water rose to tens of thousands of millimeters. During this process, the furnace shell of the hot blast stove is subject to the thrust generated by thermal stress, cyclic expansion and contraction fatigue stress, and expansion of the refractory brick lining. Especially when working at creep and sub-creep temperatures, under the dual effects of thermal expansion and explosion pressure, pipes and protective shells often cause brittle failure. Therefore, in the external combustion hot air protection, there are many more components that require a corrugated compensator than a blast furnace.