Blagdon B25 PTFE Diaphragm Pump

High Suction, Atex approved Pump for aggressive and hazardous chemicals.

Fully Submersible Pump.

Up to 136 l/min,

1″ Air Operated Diaphragm Pump,

PTFE Construction.

The pump chambers are alternately filled and emptied by drawing fluid in through a common (suction) inlet, and out through a common (discharge) outlet. The diaphragms in each chamber are linked by a common shaft so that they move backward and forwards in unison. Compressed air is directed by the air valve alternatively, behind each diaphragm, to power discharge strokes. Pump speed, fluid output, and pressure (or head) is controlled by increasing or decreasing the flow of compressed air to the pump.
The delivery can be simply controlled by restricting the flow of the air to the air inlet.

This pump is available as an Atex approved unit for use in potentially explosive

atmospheres Group II category 2

Common applications:

  • Aggressive & hazardous chemicals
  • For use in Atex areas/zones
  • When liquid to metal contact is not acceptable
  • When electrical power is not available

Max Capacity: 136 ltrs/min (36 USgal/min)

Max Pressure: 7 bar (102 psi)

Max Viscosity: 5000 cP

Temperature Range: Up to 100°C PTFE & Conductive PTFE

Categories: ,


Pump type: Air Operated Double Diaphragm Pump
Control: Valve in air inlet (not included)
Materials: PTFE casing (see options)
Fluid Connections: 1″ (see options)
Max Solid diameter: 3mm
Max Flow Rate: 136 l/min
Displacement: 0.475 litres/stroke
Max Discharge Pressure: 7 bar
Air Inlet: 3/8″ BSP(F) or 3/8″ NPT(F)
Pump weight: Approx 40kg



  • Simple construction, easy to maintain
  • Available in virgin and conductive PTFE
  • Chemically inert
  • Flanged end connections
  • ATEX approved – intrinsically safe
  • Reliable, proven pneumatic air valve
  • Strong, robust design


Casing materials: PTFE or Conductive PTFE

Internal material options: Nitrile, EPDM, Neoprene, Santoprene, PTFE, Viton (FKM)

Fluid Connection options: 1″ BSP(F), 1″ NPT(F), 1″ ANSI #150 Flange

Like all air operated diaphragm pumps, this pump requires a compressed air source to function.
Need a compressor and pump combo? Check out the compressors in the “Other Products” menu tab.


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