Diaphragm metering pump
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How should a diaphragm metering pump be started and stopped in a proper manner?
This post was last edited by ylb913 on 2016-12-13 06:15. Diaphragm metering pumps are positive-displacement pumps; the outlet valve must be opened before starting (the inlet valve also needs to be open), otherwise the outlet pressure will rise too quickly, which may lead to overpressure at the pump’s outlet. When stopping the pump, press the stop button first, and then close the outlet valve after the pump has stopped. The inlet and outlet of the diaphragm metering pump are both equipped with check valves; under normal conditions, when the pump is not in operation, the opening of these inlet and outlet valves prevents the fluid from flowing back.
The technical information provided by the manufacturer is: set the stroke to zero, then start the pump, open the outlet valve, and finally adjust the stroke to the appropriate position.
Don’t worry about it; the inlet and outlet valves are always open. The manufacturer does this to better protect the pump; once it works properly on the first try, there’s no need to worry about it anymore. Only those who have nothing better to do should adjust the stroke.
First, confirm that the outlet valve is open and there is liquid in the tank; adjust the handwheel to the 0 position； Start the motor ； Open the outlet valve ； Finally, the flow rate is adjusted by turning the handwheel.
Follow the instructions; proper use is a prerequisite
Setting the stroke to zero ensures that the pump starts under no load. Before starting the pump, it is necessary to check whether the inlet and outlet valves are open; once that is done, the pump can be started and the desired stroke adjusted. For greater accuracy, it is also advisable to conduct a test to verify that the motor’s rotation direction matches the indicated direction. The manufacturer’s recommendations are also correct, as starting the pump under no load allows the outlet valve to be opened after the pump has started, after which the stroke can be adjusted. During this process, it is possible to observe how the pump operates, checking for vibrations or leaks, etc. However, in practice, the stroke is usually fixed once the inlet and outlet valves are open, and the pump can be started right away.
In actual operation, no one will go back and adjust the schedule; usually, the inlet and outlet valves are simply opened and then operation is started.
There is no need to close the inlet and outlet valves on regular days
The diaphragm metering pump comes with an instruction manual; you can take a look at it! Because we have just installed it as well and haven’t run it yet; we saw it in the attachments during the inspection!
First, confirm that the outlet valve is open and there is liquid in the tank; adjust the handwheel to the 0 position； Start the motor ； Open the outlet valve ； Finally, the flow rate is adjusted by turning the handwheel. Well said