I have a question regarding the pump outlet venting issue
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I installed two vent valves at the pump outlet: one between the check valve and the pump outlet, and another drain valve that I placed between the check valve and the shut-off valve. This is how I designed the flow process. But how should I install the drain pipe and the vent pipe? Since the valves at the pump outlet are located on the vertical pipe, I made openings on the side – with the drain pipe pointing downward and the vent pipe pointing upward?
Generally, a vent line is connected in front of the pump’s shut-off valve and leads to the vacuum tank, serving as a vent mechanism.
According to clause 2.0.9.5 of HG20570.18, for smaller pumps, a drain valve located between the check valve and the isolation valve can be used as an exhaust valve. I don’t understand this, because drainage occurs in a downward direction; since the exhaust valve faces upward, how can it serve as a substitute? ? ?
Personally, I suggest installing downward and upward elbow fittings on the pipeline after the drain valve; use the upward one for emptying and the downward one for draining.