How to choose a suitable pneumatic diaphragm pump?

The pneumatic diaphragm pump is a commonly used positive displacement reciprocating pump in the industry, which has a wide range of applications and is easy to use and maintain. However, some customers report that the use effect of the diaphragm pump has not reached expectations, and the accessories are easily damaged during use. In addition to buying low-quality products, the reasons for these problems are partly because the most suitable model was not selected when purchasing. To choose a diaphragm pump suitable for your working conditions, the main considerations should be material, flow, suction height, head, particle size, temperature, viscosity, etc. The following is our suggestion for you.

1. First, determine the material of the diaphragm pump. Common pump body materials are cast steel, nodular cast iron, aluminum alloy, stainless steel (304/316/316L), engineering plastics (plastic polypropylene), and fluorine plastic (PVDF), according to the liquids transferred to choose. Generally, cast steel, nodular cast iron, or aluminum alloy materials are selected for pumping non-corrosive liquids. For corrosive liquids, stainless steel, plastic, or fluorine plastic are selected according to the degree of corrosion. In the case of uncertain liquids characteristics, it is recommended to choose the same material as the transfer pipe. If the liquid temperature is high, it is recommended to use stainless steel and PVDF diaphragm pumps. For liquids with hard particles, it is recommended to use metal diaphragm pumps. After selecting the material of the pump body, it is necessary to select the fluid contact parts of the diaphragm pump, which is also very important to the user experience. The diaphragm pump's fluid contact parts refer to the diaphragm, ball, and ball seat. The materials are divided into three types, Teflon, polyether, super Teflon, etc., which should be selected according to the corrosiveness, abrasiveness, and temperature of the liquids.

2. Determine the model size of the diaphragm pump, which can be selected according to the flow or caliber. The marked flow rate of the pneumatic diaphragm pump refers to the clean water test value under the condition of 0 suction height and 0 head under the drive of 7 kg of stable compressed air. The actual flow rate should be estimated according to the working conditions (the suction height and head will affect the flow rate, please refer to the flow graph or ask the manufacturer to determine). Try to choose a diaphragm pump with a flow rate that matches the pipe diameter, but if the caliber and flow rate does not match, you can also install a reducing joint at the inlet and outlet (the diameter change will affect the life and flow of the diaphragm, so the variable diameter range should not be too large). Pneumatic diaphragm pumps are positive displacement pumps, which have a low shear rate to materials and can transfer liquids with particles, but the size of the particles to be transferred must be smaller than the maximum permitted particle diameter of the pump. Oversized particles need to be filtered before pumping.

3. Pneumatic diaphragm pump can transfer viscous materials below 10,000 cps, but when transferring more viscous materials, you should choose a diaphragm pump with a flow rate one size larger than the required flow rate, because the flow rate data of pneumatic diaphragm pumps are all tested with clean water. It is calculated that the greater resistance of viscous materials will reduce the flow rate.

Pneumatic diaphragm pump customer use site

4. When using a diaphragm pump to transfer liquids with high sanitary requirements such as food or medicine, you should choose a sanitary pneumatic diaphragm pump made of stainless steel. Because the inner and outer walls of the sanitary pneumatic diaphragm pump are mirror-polished, there are no dead spots, and it is easy to disassemble and clean. The design of ordinary pneumatic diaphragm pumps cannot meet sanitary requirements.

GODO sanitary diaphragm pump