Alamo 75 vac pump, sap sucker+Millpore 600gph R.O. question

[Parker]

In the N.H. weekly Market bulletin there ia a Alamo 75 Vacume pump (no Moter) for $400. Does anyone know what kind of capacity a pump like this has? I plan on running the pump I get with a 5 horse Honda, Is that sized propley? Is there a formula for inches of mercury, Cubic feet a minuteand horse power?? What do you look for with a used Vac pump? ALSO in the same add there is a sapsucker for $250 and a Millpore 600gph R.O. machine for $400 Good Deal??? Thanks, Parker

[powerdub]

I would be careful buying an RO machine for 400. There has to be a lot wrong with it. I have never heard of that kind of vacuum pump but if I had to guess I would say the 75 is 75 cfm. If that is the case a 5 hp motor should be fine. My pump is five horse 75 cfm. The sap sucker sounds like the best deal. A friend of mine has one and loves it. If it runs well the only thing he has go wrong with it is the diaphragm goes on it and they are cheap to replace.

[sugaring42long]

The alamo 75 is 75 cfm " new zealand ". Which means its rated at 0" of mercury. At 15" of mercury its rating is cut in half or 37.5 cfm. The rpm and condition of the vanes will determine actual cfm.
I think the max rpm of a 75 is 1200 rpm. If you go below about 700 rpm the vanes won't fully expand and no vacuum.
A 5 hp gas engine will struggle at full cfm. 7 to 10 hp gas is required unless you gear it down to 700-800 rpm.

This pump will handle 3000 - 4000 taps !!!! Hope this helps.