Does HG/T20592 flange require verification when used as a equipment flange?
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This post was last edited by 311yj on 2023-4-14 23:06. It is a small device made of 304 material, with an outer diameter of 159, a wall thickness of 6, and an inner diameter of 147; the cylinder body is constructed from a steel pipe with dimensions φ159×6. The operating pressure is 3.2 MPa, the design pressure is 4.0 MPa, and the value calculated using SW6 software for the hydrostatic test is 6.4 MPa. Operating temperature: 320°C, design temperature: 400°C. The upper head and the cylinder are connected using HG/T20592 flanges WN150-63RF. Question 1: This device has an inner diameter of 147 and a total volume of over 30L; is inspection required? Question 2: Referring to the pressure and temperature rating table in standard HG/T20592, for PN63, 2C1, with an operating temperature of 350°C, the maximum allowable operating pressure (gauge pressure) is 34.5 bar, which is equivalent to 3.45 MPa. However, the operating temperature of my device is only 320°C, and the operating pressure is 3.2 MPa, which is lower than the 3.45 MPa specified in the table. Can the WN150-63RF be used directly as the equipment flange? (I used SW6 software for the calculations, and found that the WN150-63RF case could not be processed successfully; the calculations could be completed only after increasing the effective thickness of the flange by 5 mm.) But many people on the Internet say that the SW6 software is too conservative in its calculations, and many standard flanges fail to pass the checks). Since the customer does not need to provide a calculation sheet, should the WN150-63RF standard flange be chosen directly? Is it still necessary to thicken it?
Question 1: According to the Special Equipment Safety Law, pressure vessels with an inner diameter greater than 300 mm and a volume exceeding 30 L are subject to surveillance inspections. Therefore, this device has an inner diameter of 147 and a volume of over 30L, requiring surveillance testing. Question 2: From a standard perspective, as long as the flanges used in the equipment meet the standard requirements, they can be used. However, depending on the actual conditions and the requirements of engineering design, it may be necessary to increase the effective thickness of the flange based on the calculation results from SW6 software, or to select a flange with higher strength in order to meet the design requirements. Therefore, it is recommended to increase the effective thickness of the flange based on the calculation results from SW6 software, or to choose a flange of higher strength, in order to ensure the safety of the equipment while also meeting the design requirements. When standard flanges are used, if it is not possible to perform calculations using SW6 software, this must be explained in the design calculation document, and either an increased effective thickness or flanges of higher strength must be used. .
In fixed-volume regulators, monitoring and inspection are required when the following conditions are met simultaneously: (2) the volume is 30 L or more, and the inner diameter is 150 mm or more. For positive-displacement types with a volume of over 30L but an inner diameter of less than 150mm, I understand that no supervision or inspection is required.
I think the meaning of “ and” is to possess things simultaneously.
Question 1: According to GB150 \"Pressure Vessels\", during hydrostatic testing, pressure vessels with a volume of 1.2 m3 or more require supervision. Under these circumstances, the total volume of this device exceeds 30L, and it requires supervision and inspection. Question 2: Based on the information you provided, the maximum allowable operating pressure gauge pressure for the HG/T20592 flange WN150-63RF is 34.5 bar (3.45 MPa), while the operating pressure of the equipment is 3.2 MPa, which is lower than the maximum allowable operating pressure for the flange. Therefore, in theory, it is possible to directly use HG/T20592 flanges WN150-63RF to connect the equipment. However, since the effective thickness of the flange calculated by SW6 requires an increase of 5 mm to meet the verification criteria, it is recommended to consider increasing the number of bolts on the flange in order to enhance the connection strength and ensure its safety and reliability. When using equipment with standard flange connections, it is necessary to ensure the proper tightness of these flange connections as much as possible, in order to prevent loosening and leakage. It should be noted that if there is a mismatch between conditions such as the design temperature and the operating temperature, additional calculations and analyses of the flange are required to determine its suitability and reliability.