Issues regarding the interlock for stopping pumps at high levels in the tank area
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Has anyone come across a system where the solvent is pumped from a pump to a solvent storage tank outside the workshop, and then a level sensor or a weighing module is used to trigger an interlock that stops the pump in that tank – that is, when the desired volume or weight of solvent is reached, the pump in the tank stops automatically. There are a few issues in this regard: First, if several workshops are using the same solvent simultaneously, can this system not be used? Also, what equipment needs to be installed on the level gauge for controlling the pump shutdown based on the liquid level? Has anyone encountered such situations? Please share your experiences
Level switches are used for safety purposes, but a more cost-effective solution is to install weight sensors. Additionally, an on-off valve should be installed on the pipelines carrying the same solvent between different workshops; this valve can be used to cut off the flow when the specified weight is reached. In the PLC program, it can be programmed so that if several on-off valves are in the off state, the pump will stop
Of course, this approach cannot be used when the same pump serves multiple users; instead, one or two isolation valves should be installed on each tank’s inlet pipeline, along with level gauges, to enable interlock at high levels； No special equipment is required on the level gauge; it is sufficient that the gauge can send a remote signal to the shut-off valve or to the power control system of the pump.
I completely agree with what was said above. Additionally, it can also be set in the DCS: to interlock and stop the feed pump when all user shut-off valves are closed. When the user opens the cut-off valve to feed material, the system pressure drops, causing the interlocked feed pump to stop and the feed pump to start. Providing it at regular intervals every day is also a good approach.
Reply to 5# jeffery: So, if such a system is to be developed, are there any requirements regarding the selection of level gauges? Could you recommend some models of level gauges?
If several workshops are using it simultaneously, it is of course not possible to use interlock to stop the pumps. Generally, the level gauge sends a signal to the shut-off valve on the line of the inlet tank; once the shut-off valve stops, the pump also stops automatically!