I need advice on the interlock setup for the storage tank’s vent valve and isolation valve!
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This post was last edited by Clgg0822 on 2021-12-10 at 11:38. The design pressure for the atmospheric storage tank is 0–3 Kpa; it contains volatile substances and does not have a nitrogen seal. The breathing valve selected has an exhaust pressure of 1.75 Kpa, while the interlock setting for the shut-off valve is 1.3 Kpa. Is this setup reasonable? Is the breather valve usually in a non-operational state? I’m sorry; I didn’t explain it clearly at first. Here’s what it is: both the breather valve and the shut-off valve are connected in parallel to the exhaust main pipe, and both serve the same purpose – namely, regulating the exhaust pressure. But the set pressures for the two are different, so I’m a bit confused!
The topic seems to cover a wide range; it would be best to provide a schematic diagram along with the area where the linkage is severed. For reference.
Where does the shut-off valve lead to? What is the purpose of the design?
It’s not clear! ! Is the shut-off valve the one for feeding? Is feeding not allowed when the pressure reaches 1.3 KPa? ? Normally, when feeding material, the pressure will definitely rise, and the breathing valve will surely discharge air.
Feed is supplied to the tank normally; once the pressure rises to the interlock pressure of the shut-off valve, the automatic valve opens to release pressure, and it closes again when the set pressure is reached； The breathing valve is set at a pressure higher than that of the automatic valve, serving as a protection mechanism in case the pneumatic valve fails or malfunctions.
The text is not clear either, and the images are unreadable. It’s best to upload a complete one.
It should be the function of an emergency relief valve, which prevents overpressure in case the breather valve fails (it can both release pressure and, under special circumstances, replenish pressure).
Since it is an emergency backup device, its pressure setting range is wider than that of a breathing valve (the pressure at which pressure relief occurs is higher than that of a breathing valve, while the pressure at which air supply starts is lower than that of a breathing valve).
If emergency pressure relief manholes are to be installed on the storage tank now, then what’s the need for interlocked shut-off valves?
Backpressure exhaust should be considered a hazardous material; under normal conditions, the interlock valve is used for exhaust, and in the event of a failure in its operation, the breather valve takes over, providing dual protection