Help: Throttle orifice plates for vacuum pipelines
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Seeking advice: The vacuum system uses nitrogen to regulate the system pressure. The pressure in the vacuum system is 60 kPaA, while the maximum pressure at the gas inlet of the vacuum pump is 3.3 kPaA. The pumping capacity of the vacuum pump is 280 m3/h, and the performance curve relating pumping capacity to pressure remains relatively constant. I am considering installing a flow-limiting orifice plate in front of the vacuum pump in order to reduce the pressure – thereby reducing the amount of nitrogen required. Is this approach feasible? If not, why?
You have already controlled the nitrogen control valve using the RT pressure signal – why is it necessary to add an additional restriction? If necessary, it’s simply a good idea to add another valve. It is recommended that, until you understand the principles behind the process, it is best to follow the original design.
Personally, I think a proportional control system should be implemented at this point: nitrogen should be added when the pressure is low, and vacuum should be created when the pressure is high
The system generates very little non-condensable gas, so it is not possible to use a pressure control valve; meanwhile, the vacuum system requires a high rate of gas extraction, and a large amount of nitrogen is needed to maintain the system pressure
In fact, the vacuum pump chosen is too large; the actual amount of non-condensable gas is very small. To ensure the vacuum pump can operate, more nitrogen needs to be supplied, but excessive nitrogen consumption is a problem. Therefore, a flow-limiting orifice plate is intended to reduce the amount of gas supplied to the vacuum pump, thereby saving nitrogen. In this case, it is relatively straightforward to replace the vacuum pump; or perhaps the gas from the vacuum pump’s outlet could be returned to the storage tank, and the pressure control valve could be modified to regulate this reflux flow
You can also try reducing the opening of the vacuum pump inlet valve to create throttling
The methods mentioned for the fifth and sixth floors are feasible; I wonder whether using flow-limiting orifice plates will work as well, and why
That's what we did. You’re right