Temperature-Resistant, Heated Pumps

Using diaphragm pumps for gas analysis in exhaust gas measurement poses a particular challenge: When gases at high temperatures come into contact with a cold pump head, they begin to condense, leading to false test results! KNF soon realizes that the only solution is an integrated heater.

In no time at all, the inventors at the testing laboratory design a pump with temperature-resistant components and an electric heater in the diaphragm head. And so the first heated diaphragm pump is born. To protect the pump against high temperatures, specific components are made from aluminum; a corrosion-resistant steel version was also developed. This allows the pumps to handle gases at temperatures of up to 200 degrees Celsius and ensures safe operation even at high ambient temperatures.

These heated pumps soon also find a home in flame ionization detectors (FIDs), which are used in industry to measure the hydrocarbon concentration in gases. These devices rely on KNF pumps to draw in an air sample and force it into a burner. To protect against condensation, both the pump head and the feed line are heated to 200 degrees Celsius. The pump’s diaphragm and valves are made of Teflon, while the parts that come into contact with the gas are made of anodized aluminum.

The idea of heated pumps has caught on and the technology has made great strides since the 1970s. Today the pumps are even capable of transferring process gases at temperatures of up to 240 degrees Celsius without condensation. The pumps come equipped with thermostatic temperature regulation or an electronic control. The settings for pump head heating can be adjusted on an operating panel or controlled via computer using the software included.