What is Diaphragm Pumps

A photo about a diaphragm pump from Okmarts

Figure 1: Diaphragm pump from Okmarts.

A diaphragm pump (also known as a Membrane pump) is a positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or teflon diaphragm and suitable valves on either side of the diaphragm (check valve, butterfly valves, flap valves, or any other form of shut-off valves) to pump a fluid.

1. Function

The function of the diaphragm pump in the control process is to receive the control signal from the regulator or computer, change the flow of the regulated medium, and maintain the regulated parameters within the required range, so as to achieve the automation of the production process. If the automatic adjustment system is compared with the manual adjustment process, the detection unit is the human eye, and the adjustment control unit is the human brain, then the execution unit diaphragm pump is the human hand and foot. In order to realize the adjustment and control of a certain parameter in the process, such as temperature, pressure, flow, liquid level, etc., the diaphragm pump is indispensable.

Figure 2: Diaphragm pump can receive the control signal from the regulator or computer.

2. Materials

There are five commonly used materials for pneumatic diaphragm pump: plastic, aluminum alloy, cast iron, stainless steel and Teflon. Electric diaphragm pump has four kinds of materials: plastic, aluminum alloy, cast iron and stainless steel. According to different liquid media, the diaphragm of the diaphragm pump adopts nitrile rubber, neoprene, fluororubber, polytetrafluoroethylene, polytetrafluoroethylene, etc. and is placed in various special occasions to pump various media to meet the needs.

3. Characteristics

1.It have good suction lift characteristics, some are low pressure pumps with low flow rates; others are capable of higher flow rates, dependent on the effective working diameter of the diaphragm and its stroke length. They can handle sludges and slurries with a relatively high amount of grit and solid content.
2.Pump design separates pump fluids from potentially sensitive internal pump parts.
3.Internal pump parts are often suspended and isolated within oil, to promote pump longevity.
4.It is suitable for highly abrasive, corrosive solutions.
5.It is suitable for discharge pressure up to 1,200 bar.
6.It has good dry running characteristics.
7.It can be used to make artificial hearts.
8.They are used to make air pumps for the filters on small fish tanks.
9.It can be up to 97% efficient.
10.It has good self priming capabilities.
11.It can handle highly viscous liquids. A viscosity correction chart can be used as a tool to help prevent under-sizing AOD pumps.

4. Air Compressor

Figure 3: Some diaphragm pumps are also used as air compressors.

Small mechanically activated diaphragm pumps are also used as air compressors and as a source of low-grade vacuum. Compared to other compressors, compressed ones are quiet, cheap and, most importantly, have no moving parts in the airstream. This allows them to be used without added lubrication in contact with the air, so the compressed air produced can be guaranteed clean.