Regarding the issue of automatic pump shutdown via interlock to prevent vacuum formation in dump trucks.
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For safety and to save labor, I would like to install an automatic pump-shutting off function for emptying tank trucks (Class A/B liquids, at atmospheric pressure). The designed flow rate of the pump is 50 m3/h. I have two ideas that I would like the engineer to check to see if they are feasible: 1. Install flow meters (such as vortex flow meters or turbine flow meters) in the unloading pipeline; these meters should trigger an automatic shutdown of the pump and closing of the valve when the flow rate falls below a set value ； 2. Install a pressure gauge on the unloading pipeline; the pump will automatically shut down and the valve will close when the pressure drops below the set value. Are these two options feasible? Which one is better? Thank you. If possible, could you also provide a specific plan? Thank you!
If the main concern is to prevent the tank from running empty, considering installing a fork-type level switch might be a good option.
But there are only pipes between the tank truck and the pump, no tanks. I want the pump to stop automatically once unloading is complete.
But there are only pipes between the tank truck and the pump, no pump itself. I want the pump to stop automatically once unloading is complete. If this can be used, where should it be installed?
There are many and complex pump-shutoff signals for loading and unloading vehicles; sometimes valve feedback is also used
It’s all achievable; current can also be used to achieve it
I’m not sure if you use a centrifugal pump for unloading; if so, there won’t be any issue with vacuum formation. Additionally, installing a no-load and overload protector on the unloading pump will result in a much lower current when pumping air after the liquid has been drained. By adjusting the current protector according to this principle, the problem can be resolved.
Personally, I think the first option is better; using pressure interlock control results in greater fluctuations
There’s no need for such complexity! Just add a low-current protection device to the motor cabinet, so that it shuts down automatically when there is no load
1. Generally, a motor’s coils will only burn out due to continuous overheating from overload; the motor will not be damaged when running under no load. It’s just a waste of electricity. You asked whether, after installing a motor, people usually test its forward and reverse rotation, and whether the no-load current remains stable during one or two hours of operation