Problem with the gasketed flange on the outer cover side of the floating head heat exchanger?

The floating-head heat exchanger is a highly efficient heat exchange device widely used in industries such as chemicals, petroleum, and power generation. When designing and manufacturing floating-head heat exchangers, whether to use a gasketed structure for the flange on the outer cover is a matter that requires careful consideration. Regarding the question you raised, I can provide the following explanation: 1. The issue of the inner diameter of the gasket ring and the outer diameter of the floating tube sheet: In the design of floating-head heat exchangers, the inner diameter of the flange on the outer cover side usually needs to match the outer diameter of the floating tube sheet, in order to ensure that the tube bundle can pass through smoothly and to maintain the sealability and structural strength of the heat exchanger. Standard GB/T151 specifies that the outer diameter of a floating head is usually the inner diameter Di of the cylinder minus twice the cylinder thickness b1, in order to provide sufficient space for installation and maintenance. If gaskets are used, their inner diameter is often slightly smaller than the outer diameter of the tube sheet; typically by 8 mm, to facilitate installation and removal. If the inner diameter of the gasket ring is smaller than the standard requirements, it may indeed conflict with existing standards; in such cases, the value of b1 can be adjusted appropriately (that is, by adjusting the outer diameter of the tube sheet or the thickness of the cylinder) to meet the requirements. Of course, this needs to be done while ensuring the structural strength and sealing performance of the heat exchanger, which may involve redesign and verification. 2. The issue of inconsistent inner diameters between the cylinder and the flange: Inconsistent inner diameters can make it difficult to insert the tube bundle, especially when the tube bundle is tightly packed or contains a large number of tubes. The presence of gaskets may limit the space available for the tube bundle to pass through, increase assembly difficulties, or cause additional friction as the tube bundle expands and contracts. To solve this problem, designers need to take into comprehensive consideration the arrangement of the tube bundle, the connection method between the cylinder and the flanges, as well as the ease of maintenance during the design phase. Sufficient space must be ensured for the assembly and disassembly of the tube bundle, while also ensuring that the normal operation of the heat exchanger is not affected. Conclusion: The use of a flange structure with a gasket ring depends on the specific application requirements and the complexity of the design. In some cases, simplified flange connections may be more advantageous for manufacturing and maintenance ； In other cases, the gasket can provide better sealing and structural support. When designing and manufacturing heat exchangers, it is necessary to take into comprehensive consideration various factors such as the size of the heat exchanger, operating conditions, and maintenance requirements. If standard solutions cannot meet specific requirements, custom design or special structural arrangements may be necessary to address the issues caused by inconsistent inner diameters, while ensuring that the performance of the heat exchanger remains unaffected. In practice, it is usually necessary to work closely with the designers, manufacturers, and users of the heat exchanger to find the most suitable solution. .

Thank you for the reply from the second floor, but I would like to clarify that the outer diameter of the floating head plate is equal to Di-2b1; here, b1 does not represent the thickness of the cylinder, as specified in Table 6-5 of GB/T151.

The outer diameter of the tube sheet will decrease accordingly; there’s nothing wrong with that. The circular limit for the tubes arranged on the tube sheet might need to be reduced. Go ahead and do some calculations

While maintaining the heat exchange area, reducing the diameter of the pipe layout means decreasing the number of heat exchange tubes.