Diaphragm pump

Encyclopedia : D : DI : DIA : Diaphragm pump

A diaphragm pump is a positive displacement pump that uses a combination of the reciprocating action of a rubber or teflon diaphragm and suitable non-return check valves to pump a fluid. Sometimes this type of pump is also called membrane pump.

There are two main types of diaphragm pump:

In the first type, the diaphragm is sealed with one side in the fluid to be pumped, and the other in air or hydraulic fluid. The diaphragm is flexed, causing the volume of the pump chamber to increase and decrease. A pair of non-return check valves prevent reverse flow of the fluid.
The second type of diaphragm pump has one or more unsealed diaphragms with the fluid to be pumped on both sides. The diaphragm(s) again are flexed, causing the volume to change.

When the volume of a chamber of either type is increased (the diaphragm moving up), the pressure decreases, and fluid is drawn into the chamber. When the chamber pressure later increases from decreased volume (the diaphragm moving down), the fluid previously drawn in is forced out. Finally, the diaphragm moving up once again draws fluid into the chamber, completing the cycle. This action is similar to that of the cylinder in an internal combustion engine.

Applications

Diaphragm pumps may be low lift (flooded suction), low pressure pumps with low flow rates. They can handle sludges and slurries with a moderate amount of grit and solid content. Excessive solids cause blockages.

Diaphram pumps with teflon diaphrams, ball check valves, and hydraulic actuators are used to deliver precise volumes of chemical solutions at high pressures (as much as 5000 lbf/in) into industrial boilers or process vessels.

Diaphragm pumps can be used to make artificial hearts.

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.