Piping and valve technology: [Weekly topic] From 11-4-1 to 4-10 – What pressure difference before and after the valve requires the installation of a pressure equalization line?
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This post was last edited by flute6 on 2011-4-1 at 10:12. What pressure difference before and after the valve requires the installation of a pressure equalization line? Those who actively participate in the discussion will be rewarded.
This post was last edited by kaminocmyhc on 2011-4-6 at 14:56 to 2 to 3 MPa. It’s already difficult to open.
This post was last edited by kaminocmyhc on 2011-4-6 at 14:58. The following information was found on the forum; I hope it will be helpful. Pressure equalization refers to the process of balancing pressures between two systems or devices that have uneven pressure levels. Generally, when the pressure difference between two devices exceeds 0.3 MPA, pressure equalization is necessary in order to connect those devices. The voltage equalization must be done slowly. If it is too fast, it can cause overpressure in the subsequent equipment, or lead to a too rapid drop in pressure in the preceding equipment, resulting in danger. For example: you turn off the compressor. The outlet pressure is 8.0 MPA, while the pressure in the subsequent process is 3.0 MPA. At this point, you should slowly open the bypass valve near the compressor’s outlet; only after the pressure in the subsequent process has been balanced with the pressure at the compressor’s outlet can the compressor’s outlet valve be opened. The voltage equalization speed is too fast. It will cause the compressor outlet pressure to drop too rapidly, leading to a cascade shutdown of the compressor.
In accordance with Section 4.1 of the \"General Rules for Valves,\" large-diameter gate valves must be equipped with bypass valves, and the specific requirements are as follows: for pressures of 2.5 Mpa and diameters of DN400 and above； 4.0Mpa class, DN150 and above ； Above DN100, 6.4Mpa class. The diameter of the bypass valve is selected as follows: for valves with a diameter of DN100~200, DN20 is chosen; for valves with a diameter of DN250~600, DN25 is selected; for valves with a diameter of over DN600, DN40 is used
Reply to 1# zeng46563: According to clause 4.1 of the \"General Rules for Valves,\" large-diameter gate valves require bypass valves, with the specific requirements as follows: for pressures of 2.5 Mpa and diameters of DN400 and above； 4.0Mpa class, DN150 and above ； Above DN100, 6.4Mpa class. : E: y* f# T( The diameter selection for the bypass valve is as follows: For valves with a diameter of DN100~200, DN20 should be chosen; X' X0 k4 E/ I- G6 r. V# W; d1 k. For valves with a diameter of DN250~600, DN25 should be selected, while for valves with a diameter greater than DN600, DN40 should be used
Above 2.5 MPa, and some have a pipe diameter of over 400.
Reply to 1# zeng46563: What was said above is absolutely correct. In actual construction projects, things can vary depending on the specific circumstances. However, I think a bypass valve can also serve to preheat the pipes; bypass valves should also be installed before and after the automatic control check valve