by Erwin Hauser, Chief Engineer, KNF Neuberger, GmbH.
Where gases with high moisture content must be evacuated during vacuum drying operations, condensate may collect in the vacuum pump head. Consequently, the pump may not perform properly and may take more time to evacuate the designated volume. New, self-drying pumps clear moisture from the pump head during the evacuation process and thus dramatically increase pump efficiency.
Vacuum is an integral part of the laboratory. While vacuum in the past was produced using central house systems, rotary vane or by water jet pumps, diaphragm pumps have recently become the standard. Diaphragm pumps use no oil and do not contaminate media. They are universally resistant to chemicals, require little maintenance, are gas tight and versatile. They also provide the optimum condition from an economic and environmental standpoint.
It is only in applications where larger amounts of condensate are produced that conventional diaphragm pumps run into difficulty when some condensate collects in the pump head. The results are a poorer vacuum and much longer evacuation times.
To solve this problem, KNF Neuberger has developed a series of PowerDry vacuum pumps based on a diaphragm principle that include a sophisticated self-drying system (patent pending). These new pumps blow the fluid out of the pump heads at high speed during the evacuation process. As part of the process, the pump heads are ventilated using a solenoid valve while the vacuum remains constant in the process. After the pump heads are dried, the pumps produce a much better vacuum and evacuates faster. Practical experiments using a vacuum drying oven revealed a measurable efficiency increase thanks to the PowerDry system.
The self-drying vacuum pump makes the system mo