Issue with the valve switching sequence
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Question: Many of our company’s equipment have two drain valves installed on their drainage pipelines. Is there any specific order in which these two valves should be opened and closed during drainage? Please explain the reason
My understanding is that when shutting it down, one should first close the first valve that is closest to the equipment, and then close the second valve that is further away from the equipment. The sequence for opening should be the opposite of the sequence for closing.
In such cases, we usually keep the root valve open and use the second valve. Once internal leakage in the valve occurs, shut off the root valve and replace the second valve.
I think so. When opening the valve, open the secondary cut first, then the primary cut. When closing the valve, close everything first, then close two more things. This not only facilitates checking for internal leaks in the valve but also represents the safest operating condition; furthermore, it helps to remove any accumulated liquid from within the pipeline.
When discharging waste, don’t even think about the first valve; it’s also a backup valve. The first valve is activated only once the second one fails. Usually, the first one is always available. Only operate the second valve.
This post was last edited by lxq700918 on 2009-11-29 22:37. Yes, open the valve at the back first, then the one at the front. The valve that is opened first tends to wear out and break; when it does, we can close the valve once and replace it with another one
The first drain valve should remain open at all times, and it should be used only when there is a leak in the secondary cut-off valve.
One valve is kept as a spare, with the other being used in normal operation