Tube condenser is a part of refrigeration system, which belongs to a kind of heat exchanger. It can convert gas or vapor into liquid, and transfer heat from the tube to the air near the tube in a quick way. The working process of tubular condenser is an exothermic process, so the temperature of tubular condenser is higher. Power plants use many condensers to condense the steam from turbines. How to solve the temperature stress difference of tubular condenser in this process?
In order to solve the temperature difference stress of tubular condenser, a series of baffles perpendicular to the tube bundle are usually installed outside the tube. At the same time, the connection between the tube and the tube sheet and the shell is rigid. When the temperature difference between the tube wall and the shell wall is large, the large temperature difference stress is produced due to the different thermal expansion between the tube wall and the shell wall, so that the tube is twisted or bended. The tube is loosened from the tube sheet and may damage the condenser.
In the use of tubular condenser, flange qualified shell is mainly used to connect, another tube plate is not connected with the shell, so that the tube can expand freely when heated or cooled. But in this tube plate, a top cover is connected, called "floating head", so this kind of condenser is called floating head condenser. Its advantages are: the tube bundle can be pulled out for cleaning; the expansion of the tube bundle is not constrained by the shell, so when the temperature difference between the two heat exchanger media is large, there will be no temperature difference stress due to the difference of the thermal expansion between the tube bundle and the shell.
In order to solve the temperature difference stress of tubular condenser when it is running, there should be a temperature difference compensation device in operation. Generally, when the temperature difference between tube wall and shell wall is more than 50 degrees Celsius, the condenser should have a temperature difference compensation device. However, the compensation device (expansion joint) can only be used when the temperature difference between the shell wall and the tube wall is less than 60 to 70 degrees Celsius and the fluid pressure along the shell side is not high.
However, it should be noted that when the shell side pressure exceeds 0.6 Mpa, other structures should be considered because the compensating ring is too thick to expand and lose the function of temperature compensation. So we should pay attention to these problems in the operation of tubular condenser.