Diaphragm Pump

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.

There are three main types of diaphragm pumps:

1. Those in which the diaphragm is sealed with only 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.
2. Those employing volumetric positive displacement where the prime mover of the diaphragm is electro-mechanical, working through a crank or geared motor drive, or purely mechanical, such as with a lever or handle. This method flexes the diaphragm through simple mechanical action, and one side of the diaphragm is open to air.
3. Those employing 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.

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.

The three main advantages of a diaphragm pump over a centrifugal pump are:

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).

Looking for A Pump? Contact Us Today.