The glass level gauge on site cannot discharge water (principle of a communicating vessel)
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The design of the on-site glass plate level gauge is based on the principle of a communicating vessel. The glass plate level gauge I have installed is used to measure water levels, and it has recently started to malfunction; there is dirt blocking the pipe that connects to the upper part. Why can’t water be drained from the gauge through the drain valve at the bottom of the glass plate? What is the reason for this? I’m not good at physics; thanks, extra points
It’s blocked at the top, water is flowing in from below; no air can get in, so it’s a vacuum and nothing can be discharged. . . . . . .
Do you mean that the glass plate is now in a vacuum, so water can’t get inside it? When it is opened, the water should flow out; under the effect of gravity, the water should flow
Is it because the pressure inside the glass panel is lower than the external atmospheric pressure, that’s why the water can’t flow down?
You can try using a glass tube filled with water, sealing it upside down to demonstrate how air pressure can be used to draw water in; the smaller the diameter of the tube, the better
Not necessarily. When the pressure inside the pipe is equal to or less than the static pressure generated by the water column, the water cannot flow out.
Insert a thin air hose and blow to push the water out. It’s not just a vacuum issue; there might also be significant resistance at the drainage outlet at the bottom, otherwise how could air not get in on its own? Just like when the tube of a saltwater bottle is removed, it can’t stay in place; a container is needed to keep the hole in the plug open
Is it blocked by a small safety ball? Close it again and then open it
It’s blocked at the top, water is poured in from below; no air can get in, creating a vacuum, and as a result nothing can be discharged