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Piston pumps, Diaphragm pumps, and you


What’s a diaphragm pump, how are they different from piston pumps, and why does the type of recovery pump matter? BHOgart’s TechTeam has the answer.

Diaphragm pumps produce pressure using a reciprocating diaphragm disk. As the disk moves, gas and liquid is drawn into the opposite chamber through a one-way valve. When the disk moves back into the first chamber, the disk pushes liquid out through a second one-way valve.

Piston pumps have a piston which moves back and forth in a cylinder, attached to a rotating crank (much like a gasoline engine). But unlike a gasoline engine, a piston-style recovery pump uses an electric motor to force the piston forwards and backwards, instead of combusting gas to cause the piston (and therefor crank) to move and rotate. As the piston moves in the cylinder, it sucks gas into it through a one-way valve. As the piston moves in the opposite direction, the liquid is pushed out through a second one-way valve.
Sound Similar? Sure does, but the differences can be immense. Here’s what you need to know:

Piston Pumps can’t touch the precision of diaphragms. This means with each cycle, the pump moves the same amount of gas/liquid as the cycle before. This means more control, more reliable operation, and ultimately a better product. In a Piston pump, each cycle can vary wildly from the last, meaning your pump can be unpredictable and cause fluctuations in flow rates.

Less Contamination
Diaphragm pumps are less likely to contaminate your extract. Not only are the seals tighter, but diaphragm pumps don’t require the use of lubricants in the diaphragm chamber.

More reliable, cheaper repairs
With fewer moving parts, low wear, and a simple design, diaphragm pumps will continue pumping long after a piston pump has required re-building. And when they do require maintenance, diaphragm pumps are easier to repair, saving you time and money over an expensive and tedious piston pump re-build.

Piston pumps are more prone to leaks than diaphragm pumps. Even if the internals of a diaphragm pump fail, the housing remains sealed and prevents catastrophic failures that can occur with piston pumps. Furthermore, all electronic are sealed and meet industry specifications for use in a hazardous and flammable environment, so even if you do experience a small leak somewhere else in your system, the pump will not provide any ignition sources.

After weighing the pros and cons of piston versus diaphragm pumps, we think the choice is pretty clear. Check out what we have to offer:

BHOgart Double-Headed Diaphragm