On 2013-04-12, J.B.Slocomb wrote:
On Thu, 11 Apr 2013 17:28:25 -0500, Ignoramus19459
wrote:

I have a question, I have a diaphragm pump here and I have never used
one before. When I supply air to this particular one, it seems to work
internally, but there is barely any suction or pressure on either
end. Maybe just a tiny amount of suction.

I thought that they can run dry and do not need priming.

What should I expect from a good diaphragm pump?

i
Likely to be worn or sticking valves. Unless the diaphragm has a hole
in it :-(


OK, I spent a lot of time with that pump. Took it apart. The valve
balls are there. The membranes are in good condition. After
disassebmly and reassembly, it does pump water very well.

Then I tried pumping old coolant from a machine into a barrel. It
worked great, then got somehow stuck and did not pump, despite
reciprocating. I assumed that the plastic balls got stuck, shook it a
bit, and then got them unstuck.

Someone told me that if I buy PTFE (Teflon) balls, they would be
lesslikely to get stuck. They are not that expensive and I wanted to
double check if that advice makes sense to you.

Thanks

i