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A double diaphragm pump in action

Double diaphragm pumps use the same ‘enlarge/compress’ process as single diaphragm pumps, but by running two diaphragms in parallel they offer a far more energy-efficient pumping solution.

By connecting two diaphragms together, they make use of the expansion of one diaphragm to aid the contraction of the other and vice versa, pumping twice as much fluid in the same time and using a lot less energy in the process.

To see an air-operated pump in operation, look at the movie below:

Pumping Process

As you can see from the movie, air is pumped into the central valve chamber which forces the diaphramps to expand and contract and this motion serves to force fluid into the pump and out again.

In this way, a double diaphragm pump can move a huge amount of fluid at high speed – in the case of a Husky 2150 air-operated diaphragm pump up to 150 gallons per minute (568 litres per minute) can be pumped at a fluid pressure of up to 120psi (8.4 bar, 0.84 MPa)

Easy to use

The marvellous thing about double diaphragm pumps is you don’t have to be especially skilled to use them. If you can use a vacuum cleaner around your home, you can learn to use a double diaphragm pump too!

This is because double diaphragm pumps are very safe to use – they are a standard feature on oil rigs and oil tankers around the world as well as other safety critical sectors such as the motor manufacturing and chemical industries

Double diaphragm pumps are self-priming, which means they can be run dry for a short time when no material is available for pumping – compare this to an electric pump which would soon burn out when there is nothing for them to pump.

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Six Tips to understand Double Diaphragm Pumps

  1. These pumps can be constructed in materials ranging from Aluminium, Cast iron, Stainless steel, Polypropylene, Acetal, Kynar (PVDF) and certain sizes in Hastelloy wetted parts are available.
  2. The moving parts internally that come in contact with the fluid being transfered, can be a combination of many materials from Aluminium to PTFE.
  3. The pumps have an inlet or suction side where the fluid enters the pump, and an outlet or discharge side where the fluid leaves the pump.
  4. The fluid when leaving the pump, will be at a given fluid pressure, that suits the application.
  5. These Double Diaphragm pumps are often referred to as Diaphragm pumps, are driven by a supply of air from an air compressor and not driven by an electrical supply.
  6. The air supply to the pump is normally regulated to a certain pressure, usually around 3 to 4 Bar, the magority of pumps have a 1 to 1 ratio, this means if the air supply is 5 Bar then the fluid leaving the pump will be 5 Bar.

Technical Specifications and Ordering Information for Husky 3275 (pictured)

Fluid inlet and outlet size . . . . . . . . . . . . . . . . . . . . . 3″ (76.22 mm)
Maximum free flow delivery . . . . . . . . . . . . . .  . . . . 275 gpm (1,041 lpm)
Displacement per cycle . . . . . . . . . . . . . . . . . . . . . . . 2.0 gallon (7.6 liter)
Air inlet size . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 3/4” npt(f)
Air pressure operating range . . . . . . . . . . . . . . . . . . 20-120 psi (1.3-8 bar)
Maximum air consumption . . . . . . . . . . . . . . .. . . . . 325 scfm
Maximum size of pumpable solids . . . . . . . . . .. . . . 0.25 in (6.3 mm)
Maximum operating temperature . . . . . . . . . . . . . . PTFE 220ºF, Geolast 150ºF, Hytrel 150ºF
Typical sound level . . . . . . . . . . . . . . . . . . . . . . .. . . . .79 dBa
Instruction manual . . . . . . . . . . . . . . . . . . . . . .. . . . . .308639

Ordering Information for Husky 3275
Part Number Material of
Ported NPT Ported BSP Construction Seats Balls Diaphragm
DK3311 DKC311 Aluminum SST PTFE PTFE
DK3525 DKC525 Aluminum Hytrel Acetal Hytrel
DK3GGG DKCGGG Aluminum Geolast Geolast Geolast
Please consult the Process Equipment Buyer’s Guide (300435) for additional configurations.