Introduction of fixed tubesheet
In the calculation of the fixed tubesheet
, the axial stress of the shell, the axial stress of the heat exchange tube and the pull-out force Q between the heat exchange tube and the tubesheet are calculated according to various working conditions with temperature difference. If one of them can not meet the strength (or stability) condition, the expansion joint needs to be set. In the strength checking calculation of fixed tubesheet, when the tubesheet thickness is determined and no expansion joint is set, sometimes the tubesheet strength is not enough, and the tubesheet thickness may meet the requirements after the expansion joint is set. At this time, expansion joints can also be set to thin the tube sheet, but it depends on the comprehensive evaluation of material consumption, manufacturing difficulty, safety and economic effect.
U-type expansion joint is commonly used in fixed tubesheet heat exchanger. It has the advantages of compact and simple structure, good compensation and low price.
With the large-scale of chemical equipment and power station, the diameter of tubesheet is becoming larger and larger. The tubesheet with the diameter of 4m-5m is very common. The characteristics of large tubesheet are large number of holes, dense, small diameter, deep, high precision and finish requirements.