GOOD MORNING:

I´m looking for some ideas to solve a problem with a external gear pump.

The gear pump is used in a vessel to move gas oil between several storage tanks.

We install a new pump after remove the previous that was the same pump type.

That is the problem that I found:

The pump start properly and start to move liquid, after a few minutes the pump make a overload sound and electric proteccion stop the electric motor .

I have found excesive vacum in inlet side an also vacum in outlet pipe.

After a few minutes if i start the pump again the process will be the same.

I have checked the elecetric motor and the turn direction an is ok.

I have cleaned the inlet filter and It was ok.

I haven`t founded any air filtration.

As I have several tanks ; I changed aspiration and discharge tanks and the results ,is always the same.

I have made this check with the relieve valve almost total open (as the manufacture indicate inthe first starter). If I tighten (or regulate a little) the relief valve, the pump overload if few seconds.

As I´m alone at sea I will apreciate any Idea about how to solve the problem.

Kind REgards