Will drilling a hole in the outlet flange of a safety valve cause stress changes?
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Safety valve on the top of the liquid ammonia storage tank: from 50 to 65; flange at the discharge port with 65 bolts; four bolt holes; butt flange with 8 bolt holes. Safety inspections revealed non-compliance with regulations, and rectification was required. Thus, the safety valve changed from 4 holes to 8 holes.
You’re not trying to change a 65 flange with 4 holes into one with 8 holes, are you?
This post was last edited by lovelife1997 on 2019-3-20 at 17:21. 1. Users are not allowed to change the structure of the safety valve itself arbitrarily. Measures: 1. Either reinstall a safety valve that matches the 8-hole flange of the pipe. 2. Either cut off the 8-hole butt flange on the pipe and weld a 4-hole DN65 flange with guaranteed quality. Choose one of the two options, but it is strictly forbidden to make any modifications to the safety valve itself – remember that!
The safety valve is more important than the pipe flange; change the pipe flange, but do not touch the safety valve.
It’s probably because the nominal pressure class of the flanges is different. For DN65 flanges, those rated at 16 kg have 4 ports, while those rated at 25 kg have 8 ports. In your case, the nominal pressure classes of the flanges don’t match. What is the discharge pressure? If the safety valve’s rating is insufficient, choose a different safety valve; if the safety valve is fine, then adjust the outlet coupling flange. Safety valves are accessories for special equipment; one cannot simply modify them at will. If an accident occurs (even if it isn’t caused by such modifications), the consequences will be severe
The explanation on the 7th floor is reasonable; safety valves cannot be altered easily.
It’s not that I want to; I’ve already done it
It’s not the grade that differs, but rather the execution standards; since no specific requirements are stated, the safety valve manufacturers follow JB/T81-94, while the actual flange standard for DN65 with 8 holes is HG/T20592-2009
It is best to add a transition pipe, changing DN50 to DN65; the valve itself should not be altered