Hello friends,

I am dealing with the automation of a fuel dispensing facility, to deliver fuel from storage tanks to heavy vehicles. From the tanks there is a PD pump (actually a few) and then a meter and a valve. I understand about taking the pulses from the meter (to count the volume) and controlling the valve (to control/stop the flow). But what I am not sure of is what to do with the pumps. Are they supposed to be on all the time? Should I shut off the pump after I have closed the valve? (i.e. desired quantity is reached)

Thank you

 

PD pumps should not run against a closed head or things start to break. There should be at the very least, an internal pressure relief valve.

If when next you fill up your car, if you listen, the pump doesn't start until the dispenser has been approved by the office. It stops when you holster the nozzle. You will hear it start even before you have opened the nozzle.

You will also note that you can close the nozzle with the pump still running but without a major pressure surge or pulse which implies something more than a simple pressure relief valve.

I'd suggest visiting the web site of one of the forecourt dispenser suppliers and see what their technical details give you.

Wayne, tank and Pump, Tokheim, Shlumberger, etc.