Valve anti-ejection design
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I would like to ask the experts: regarding the design to prevent valves from blowing out, is it required that the drive shaft does not come loose during online packing replacement when no actuator is installed?
The anti-ejection structure of the ball valve does not have a stuffing box, and the valve stem is installed from below. The valve stem will not fly out
When the globe valve is closed and there is no material behind it, the packing can be replaced online. For gate valves, as long as the medium does not pose a serious threat to humans, it should be fine even with the valve closed; however, there is space under its cover for storing materials. In short, I’ve thought about it a few times, but I’ve never dared to take such a risk.
Thank you to all for their answers. My current question concerns butterfly valves with a full shaft and no valve cover; I would like to know whether the \"blowout prevention\" mechanism is installed below the packing gland (so as to facilitate packing replacement). If the “blowout prevention” design is located above the packing, does it merely mean that this blowout prevention function does not take into account the need to replace the packing, and only ensures that the shaft of the valve will not fly out once the actuator is removed? Thank you all, please give the correct answer!
To prevent blowing out, it cannot be replaced online.
The type where the packing gland is loose and the valve stem can’t be pulled out.
The anti-extraction structure should have nothing to do with replacing the packing.
Blowout prevention is mainly aimed at ball valves