piston pump-temp problem
piston pump-temp problem
(OP)
Hello,
I have here a problem that i could never imagine of hapening and with these instruments already installed in the field...I bought around a Wob-L Piston Vacuum Pump (Rietschle Thomas) Snr:80061068 (12VDC) and i have a very specific question regarding the operations conditions of this kind of pump. I would like to know if there is a minimum flow rate required in order to limit the temperature rise (and if yes how much is it). Today after using it for 3 hours, the Teflon tubings used for the fittings just melted... and a collegue burnt his finger... So the temperature must have rised to more than 150 oC (The pump was in a paperboard box without any ventilation). The vacuum (controled by a needle valve) at the input was at around 19inHg for an input flow rate of 1.5lpm (conditions given by the flow cruve).
I really apreciate any kind of advice for this problem.
I have here a problem that i could never imagine of hapening and with these instruments already installed in the field...I bought around a Wob-L Piston Vacuum Pump (Rietschle Thomas) Snr:80061068 (12VDC) and i have a very specific question regarding the operations conditions of this kind of pump. I would like to know if there is a minimum flow rate required in order to limit the temperature rise (and if yes how much is it). Today after using it for 3 hours, the Teflon tubings used for the fittings just melted... and a collegue burnt his finger... So the temperature must have rised to more than 150 oC (The pump was in a paperboard box without any ventilation). The vacuum (controled by a needle valve) at the input was at around 19inHg for an input flow rate of 1.5lpm (conditions given by the flow cruve).
I really apreciate any kind of advice for this problem.





RE: piston pump-temp problem
Why ask us? The manufacturer probably has this information.
Where exactly did you expect the heat generated was going to go?
RE: piston pump-temp problem
i asked you this question cause i ve found some equations (to find minimum a flow rate required in order to limit the temperature rise) but the don t seem to work very well....
RE: piston pump-temp problem
That is to say, the heat capacity of a vacuum is really small.
Maybe that's why it is used inside Dewar flasks.
RE: piston pump-temp problem
Mike Halloran
Pembroke Pines, FL, USA
RE: piston pump-temp problem
in fact, the only answer that the manufacturer was abable to give me is that a need to provide a cooling for my pump...
That said do you know if the folowing equation (minimum flow rate to protect my pump from heating problems) is suitable for my case:
Qmin=P(@minflow in KW)*3600/Cp * Rho (density@Tmin)* Delta T (max temperature variation to protect my equipment)
RE: piston pump-temp problem
The actual formula is:
P=Q*Rho*cp*delta T
RE: piston pump-temp problem