Can gate valves be used as substitutes for 900# and globe valves with a diameter of over 3 inches?
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When looking at the piping specification sheets prepared by foreign engineering companies, it is specified that pipes of grade 900# are required, and gate valves should be used in place of stop valves for pipes larger than 3 inches. Why is this? Is it necessary?
Your questions should be directed to the person who prepares the piping specification sheet, as well as to those who are responsible for ensuring that the requirements specified in the piping specification sheet are followed
Your question is not clear; these two types of valves cannot be replaced arbitrarily under any circumstances, nor is it necessary to replace them.
I also think there’s a problem; I haven’t encountered any that needed to be replaced.
In my opinion, it is likely that under high-pressure conditions, large-diameter globe valves do not perform as well as gate valves; the reason lies in structural differences, as the structure of gate valves is better suited to withstanding pressure； They are all large-bore, high-pressure globe valves and gate valves; in terms of performance, gate valves should be more stable.
I don’t think it’s necessary. Globe valves have good sealing performance, but at high pressures and large diameters, the torque and axial forces associated with such valves can be very high, which puts significant strain on operating the valve. The common solution nowadays is to use a design with double valve discs and an internal bypass, allowing fluid to flow in from above and out from below. However, a 3'' 900LB version doesn’t even require this; it can be designed and manufactured normally. Thank you, it’s just my humble opinion!