Air-operated Double Diaphragm Pumps from Kelair Pumps

Case Study
Sales Engineer Mark Butterfield (NSW)

Small Sandpiper big on accurate dosing

Kelair's standard range of Sandpiper air-operated double diaphragm (AODD) pumps are controlled via an air-operated pilot valve that directs air flow inside the pump.

However, Sandpiper pumps can be driven with a factory- fitted electrically operated solenoid valve in place of the normal pilot valve. The solenoid valve fulfills the same function as the pilot valve, controlling the main air valve which directs compressed air alternately to each side of the pump's centre section, which in turn actuates the pump's diaphragms.

The solenoid valve option was put to good use when one of Kelair's customers from the food processing industry enquired about a dosing pump for acetic acid.

The customer's application required a pump that would dose a fixed amount of acetic acid, based on a pulsed voltage output from the processes' control system. Ideally the pump would deliver a fixed and repeatable amount of acid per pulse, allowing the total amount of acid required to be accurately dosed.

The customer did not have the lead time, or budget, for a specifically designed dosing pump with the appropriate pulse controls, so Kelair's engineers recommended a Sandpiper pump, fitted with solenoid activation.

Sandpiper pumps are positive displacement pumps and have a fixed volume per stroke of each diaphragm, so these pumps will deliver a specific amount of liquid for a given number of strokes.

The solenoid valve can be operated on 12VDC, 24VDC, 24VAC and 240VAC and can be controlled by energizing and de-energizing the solenoid which will give alternative diaphragm strokes. This combination of Sandpiper pump and solenoid control gave the flow rate and accuracy required for the customer's application.

Kelair specified the second smallest pump in Sandpiper's range, the S05. The pump was factory-fitted with the solenoid kit and delivered to the customer. The customer actually uses the identical model of pump, fitted with the conventional air section in another part of the factory, and so was able to reduce the spare parts inventory as almost all the parts are interchangeable.

The pump was installed and has worked well. The customer is very pleased with its performance and has bought a second, identical pump for a similar application elsewhere in the factory.