Why are the heat exchange tubes in fixed-tube-sheet heat exchangers of fixed length?
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Why is the length of the heat exchange tubes in the design of fixed-tube-sheet heat exchangers a fixed value or a multiple of a fixed value? The specific reason is unclear; those who know it please help to clarify, thank you
This post was last edited by xlxuiin on 2015-11-23 at 14:57. The meaning of fixed length for seamless steel pipes. The length is the same as agreed upon by the customer. Common standard lengths include 6 meters, 9 meters, etc. According to standards such as API 5L and ASTM A106, seamless steel pipes are available in both fixed-length and variable-length forms. Some special applications require fixed lengths in order to facilitate orderly storage and transportation, but in most cases they are of variable length; this is because during the production process, factors such as wall thickness and the quality of the raw materials are dynamic, which inevitably results in variations in the length of the finished products. In fixed-tube-sheet heat exchangers, the lengths of the heat exchange tubes are all identical; fixed-length or multiple-fixed-length tubes are used based on the designed length of the heat exchanger to reduce waste ； Due to the structural characteristics, the heat exchange tubes are subject to thermal stress; therefore, it is necessary to keep the production process, the raw material, and the wall thickness of these tubes as consistent as possible.
It is generally determined based on requirements, but it is usually best to use the standard recommended dimensions for calculations during design, as long as the process requirements are met.
I just want to know why this recommended size exists
I guess it’s to have a unified standard for easier production, transportation, and management, right? Just like bolt specifications such as M12, M14, M16, and so on. It seems that the specifications for the heat exchange tubes aren’t entirely fixed either; specifications such as 1500, 2000, and 4000 are also quite common.
There is a certain price difference between steel pipes in fixed length and extended length versions (the extended length version is more expensive). Considering costs, heat exchange tubes are usually supplied in fixed length~~ Of course, for custom-made products, the extended length version may be necessary~
Generally, manufacturers produce pipes in fixed lengths, and the same requirement applies when designing heat exchangers, as it facilitates processing; these lengths are now commonly referred to as universal standards!