VerderairThe series of Verderair double diaphragm pumps are highly engineered diaphragm pumps, delivering a smooth, reliable flow for all circumstances. The new air valves design guarantees a perfect, non-stalling operation, even at low pressure. The air valves do not need any lubrication. Thanks to their unique design, the pumps are able to handle very abrasive and/or viscous products.

The Verderair pumps will run dry indefinitely without damage. Verder has selected those materials which offer the best combination of benefits to the end user. The used wetted pump part materials are Acetal, Polypropylene, Kynar, Aluminium, Cast Iron and stainless steel. For ball and/or diaphragm, Verder selected PTFE, Hytrel, Santoprene, Viton, BUNA-N, SS and Acetal.

These diaphragm pumps provide flexible, reliable flow in all circumstances. The design of the control valve guarantees perfect operation that never jams and that does not have to be lubricated even at low compressed air pressure and high backpressure. Verder has chosen those materials that offer the end user the best combination of advantages. Both metallic and non metallic versions are available. High Pressure, FDA and Hygeinic models are also available to suit your application needs.

Principle of Operation

1. The air valve directs compressed air behind diaphragm 1 which is then passed directly to the liquid column. The diaphragm acts as a divide between the compressed air and the liquid. The compressed air moves the diaphragm away from the central block of the pump. The opposite diaphragm is pulled towards the central block by the connecting rod, which is connected to the diaphragm that is under pressure. Diaphragm 2 now carries out the air-expelling stroke; air from behind the diaphragm is then expelled through the discharge valve into the atmosphere. Diaphragm 2 moves in the direction of the central block of the pump. Atmospheric pressure then forces the liquid towards the inlet manifold, where the valve ball is moved from its seat. This allows liquid to flow freely past theinlet valve ball and fill the liquid chamber.

2. Once the diaphragm under pressure, diaphragm 1, has reached the limit of its outward stroke, the air valve leads compressed air behind diaphragm 2. This compressed air pushes diaphragm 2 away from the central block, resulting in diaphragm 1 being pulled towards the central block. Diaphragm 2 pushes the inlet valve ball onto its seating through the hydraulic forces that develop. The same hydraulic forces cause the discharge valve ball to be lifted from its seat, whilst the opposite discharge valve ball is forced onto its seat. The inlet valve ball is lifted from its seat, so that the liquid can be transported to fill the liquid chamber.

3. When the stroke is completed, the air valve once again brings air behind diaphragm 1 and diaphragm 2 starts on the air-expelling stroke.


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