What is diaphragm pump and how does it work?

Pneumatic diaphragm pump (air operated diaphragm pump) is a new type of conveying machine, which uses compressed air as the power source. It can absorb all kinds of corrosive liquids, liquids with particles, high viscosity, volatile, flammable and highly toxic liquids.

Materials of pneumatic diaphragm pump

There are four kinds of materials for pneumatic diaphragm pumps: engineering plastics, aluminum alloys, stainless steel, and cast iron. The pneumatic diaphragm pump adopts nitrile rubber, neoprene rubber, fluorine rubber, PTFE, PTFE, etc. according to different liquid media to meet the needs of different users. It is placed in various special occasions and used to pump various media that cannot be pumped by conventional pumps, and satisfactory results have been achieved.

See more: What are the materials of the air-operated diaphragm pump?

Wilden AODD PUMP diaphragm pump
Wilden® Pneumatic diaphragm pumps

Applications of pneumatic diaphragm pump

Because the air-operated diaphragm pump has many advantages, the air-operated diaphragm pump is gradually invading the market of other pumps since its birth, and occupies a part of it. Pneumatic diaphragm pump has occupied an absolute dominant position in painting and ceramic industries. In some other industries, such as environmental protection, wastewater treatment, construction, sewage, and fine chemicals, it is expanding its market share and has an irreplaceable position with other pumps.

The working principle and characteristics of pneumatic diaphragm pump

The pneumatic diaphragm pump is a volumetric pump that uses compressed air as the power and the volume changes due to the reciprocating deformation of the diaphragm. Its working principle is similar to that of a plunger pump. Due to the characteristics of the working principle of the pneumatic diaphragm pump, the pneumatic diaphragm pump has the following characteristics:

  1. The pump will not be overheated: compressed air is used as power, and it is a process of expansion and heat absorption when exhausting. When the pneumatic pump is working, the temperature is reduced, and no harmful gas is discharged.
  2. No electric sparks will be generated: the pneumatic diaphragm pump does not use electricity as power, and prevents electrostatic sparks after grounding.
  3. It can pass through particle-containing liquid: because it works in a positive way and the inlet is a ball valve, it is not easy to be blocked.
  4. The shear force on the material is extremely low: the pump has little stirring effect on the material when it is working. It is suitable for the transport of unstable substances.
  5. The flow can be adjusted. A throttle valve can be installed at the material outlet to adjust the flow.
  6. Function of self-priming.
  7. It can be run dry without danger.
  8. Suitable for diving work.
  9. The fluids that can be transported are extremely wide, from low viscosity to high viscosity, from corrosive to viscous.
  10. There is no complicated control system, no cables, fuses, etc.
  11. Small size, light weight, easy to move.
  12. No lubrication is required, so maintenance is easy. Will not contaminate the working environment due to dripping.
  13. The pump can always keep working efficiently. There is no loss of efficiency due to wear.
  14. 100% energy utilization. When the outlet is closed, the pump stops automatically. There is no risk of equipment movement, wear, overload, heat generation.
  15. No dynamic seal, easy maintenance to avoid leakage, no dead point during work.

See more: Advantages of air operated diaphragm pumps

Application areas of pneumatic diaphragm pumps

IndustriesExamples of fluids
Chemical industryAcids, alkalis, solvents, suspended solids, disperse dyes, etc
Petrochemical industryHeavy oil, grease, mud, sludge, etc
Coating industryResins, solvents, colorants, paints, etc
Daily chemical industryDetergents, shampoos, lotions, lotions, hand creams, surfactants, etc
Ceramic industryMud, porcelain slurry, lime slurry, clay slurry, etc
Mining industryCoal slurry, magma, mud, mortar, lubricating oil, etc
Water treatmentLime slurry, soft sediment, sewage, chemicals, waste water, etc
Food industryLiquid semi-solid, chocolate, brine, vinegar, syrup, vegetable oil, soybean oil, honey, etc
Beverage industryYeast, syrup, concentrate, gas-liquid mixture, wine, fruit juice, corn steep liquor, etc
Pharmaceutical industrySolvents, acids, alkalis, plant extracts, ointments and other pharmaceutical liquids, etc
Paper industryBinders, resins, paints, inks, pigments, hydrogen peroxide, etc
Electronics industrySolvents, electroplating liquids, cleaning liquids, nitric acid, waste acids, corrosive acids, polishing fluids, etc
Textile industryDye chemicals, resins, glues, etc
Construction industryCement slurry, ceramic tile adhesive, rock slurry, ceiling paint, etc
Automotive industryPolishing emulsions, oils, coolants, automotive primers, oil emulsions, varnishes, varnish additives, degreasers, paints, etc
Furniture industryAdhesives, varnishes, solvents, colorants, white wood glue, epoxy resins, starch adhesives, etc
Metallurgy, foundry and dyeing industryMetal pulp, hydroxide and carbide pulp, dust washing pulp, etc

Pneumatic diaphragm pumps (AOD pumps) vs other Types of Pumps

Pneumatic one-way diaphragm pump has six advantages such as reliable quality, long service life, low noise, small vibration, never crash, and fine workmanship. It can not only pump flowing liquid, but also transport some medium that is not easy to flow. It has many advantages of conveying machinery such as self-priming pump, submersible pump, canned pump, mud pump and impurity pump.

Pneumatic diaphragm pump (AOD pump)Gear Pump
Dry Run without damageCan not be ran dry
Handle AbrasivesCan not handle abrasives
Designed for varying flow, viscosity and   head conditionsLimited ability to handle varying viscosity,   thixotropic or non Newtonian liquids
Pump pauses during zero flow without   energy consumption at dead head. Restarts once closed valve opensRelief valve required if deadheaded   with only limited time for using bypass
No rotating or close wear parts which   once wear experience large drops in flowMany Rotating and close tolerance   wetted parts
AOD Vs Gear Pump
Pneumatic diaphragm pump (AOD pump)Progressing Cavity Pump
Dry run without damageCan not dry run
Fewer less expensive wetted wearing partsExpensive rotating and close tolerance parts
Maintenance relatively easyMaintenance time consuming, labour intensive. Usually required to be   taken off site for repair as specialist tools and knowledge required for   maintenance.
Virtually no slip with thin liquids such as waterSlip increases with low viscosity fluids
Pump pauses during zero flow without energy consumption at dead head. Restarts once closed valve opensRelief valve required if deadheaded with only limited time for using bypass
Compact designLarger unit with gearbox
Handle a wide range of temperaturesLimited temperature handling capability
AOD Vs Progressing Cavity Pump
Pneumatic diaphragm pump (AOD pump)Vane Pump
Dry Run without damageLimited dry run
Fewer less expensive wetted wearing partsMore rotating and close tolerance parts
Pump pauses during zero flow without energy consumption at dead head.   Restarts once closed valve opensRelief valve required if deadheaded with only limited time for using bypass
Handles solids as large as inletLimited solids handling
Handle AbrasivesCan not handle abrasives
AOD Vs Vane Pump
Pneumatic diaphragm pump (AOD pump)Lobe Pump
Self Priming up to 7.6MLimited suction
No rotating or close wear parts which   once wear experience large drops in flowMany Rotating and close tolerance   wetted parts
Pump pauses during zero flow without   energy consumption at dead head. Restarts once closed valve opensRelief valve required if deadheaded with only limited time for using bypass
Handle AbrasivesCan not handle abrasives
Handles solids as large as inletLimited solids handling
AOD Vs Lobe Pump

Brands of pneumatic diaphragm pumps

WILDEN®, SANDPIPER®, ARO®, VERSA-METIC® are the most famous brands for pneumatic diaphragm pumps(AOD pumps). If you want to buy these brands pumps and accessories/spare parts. Please feel free to contact us: sales@northstarpump.com