A diaphragm pump (also known as a Membrane pump) is a positive displacement pump that uses the combination of a reciprocating action of a rubber, thermoplastic or teflon diaphragm, and a suitable valve on either side of the diaphragm to pump a fluid.
Diaphragm pumps are a common site in many industries. There is an extensive number of construction materials available to produce a bewildering number of configurations to accommodate difficult fluids.
When the volume of a chamber of either type of pump 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. Diaphragm Pumps deliver a hermetic seal between the drive mechanism and the compression chamber, allowing the pump to transfer, compress, and evacuate the medium without a lubricant.
An elastomeric diaphragm can be used as a versatile dynamic seal that removes many of the limitations found with other sealing methods. They do not leak, offer little friction, and can be constructed for low pressure sensitivity. With the right material consideration, diaphragms can seal over a wide range of pressures and temperatures without needing lubrication or maintenance.
Excellent Dry-Running Capacity
The diaphragm pump has the ability to create a good vacuum in the suction line. In practice, the membrane guarantees a perfect seal and a constant vacuum in the suction line, which means that the membrane pump can lift liquids to a lower level than it is (lifting capacity).
Good Drying Performance
Due to the hermetic separation of the suction chamber from the oil bath lubricated gears, the diaphragm pumps keep reasonable dry running times without the negative effects that occur with centrifugal pumps that are not safe to run dry, such as overheating and jamming of the connecting rod and piston.
Abrasion and Corrosion Resistant
Because there are no mechanical parts in direct contact with the liquid, a diaphragm pump can pump liquids that are not perfectly filtered from solid residues, such as crystals, sand, or crushed flakes (mechanical resistance). It can also be used with most aqueous crop protection products, even in mixtures with acids, solvents, abrasive particles, sediment or
sludge (corrosion resistance).