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Pump innovations offer deeper vacuum, more quickly

Edited by the Engineeringtalk editorial team Apr 12, 2001

Welch has developed two new pump designs intended for high vacuum and mass spectrometry, providing effective backing pumps for hybrid turbomolecular pumps, molecular drag pumps and gas analysers

Welch has developed two innovative new pump designs intended for high vacuum and mass spectrometry, providing highly effective backing pumps for hybrid turbomolecular pumps, molecular drag pumps and gas analysers.

Oil-free, and with low ultimate pressures, the Model 8111 and Model 2581 have been developed to offer high pumping speeds below 20mbar, cost effective solutions, and simple designs with minimal and easy maintenance.

The 8111 is designed as an OEM pump and represents a significant development in pumping technology, employing tangential technology and forced valve operation (for which there is a patent pending).

The new valve technology employed is highly efficient, with the suction valve located at the very edge of the pump chamber.

The forced valve operation and tangentially fixed diaphragm minimise dead space.

The result is a highly compact, two stage diaphragm pump which sets benchmark standards for its size by offering a flow rate of 32 l/min and delivering 1mbar ultimate pressure � performance comparable to that offered by three or four stage pumps.

As well as its size advantage, the 8111 also offers a significant cost advantage over the three and four stage pumps which would typically be used.

Applications for the 8111 include use on helium leak detectors, mass spectrometers, MVD chambers, electron microscopes, surface science engineering and reaction cell analysers.

Additionally, it will find uses on dental ovens and for degassing polymers.

Other applications include medicine and analytical engineering.

The 2581 provides the smallest possible footprint for a 100 l/min dry running pump.

The Wob-L piston pump design delivers ultimate pressures below 5mbar, yet has a footprint measuring just 19 by 32cm.

Simplicity is the key to the economical, aluminium design.

As the piston wobbles, air resistance on the upward stroke expands the Teflon seal on the piston, thus increasing the efficiency whilst compensating for the wobble action.

The pump is designed as a backing pump for hybrid turbos, MDPs and gas analysers where quick roughing of a chamber is needed, offering a higher flow rate than an oil-sealed rotary pump that might typically be used.

Achieving such deep vacuums as the 8111 and 2581 pumps offer has traditionally meant using oil lubricated pumps, but this can be undesirable in many applications.

Thus the 8111 and 2581 will meet the needs of applications requiring high vacuum but where the escape of oil vapour into the process could present a significant hazard.

The 8111 and 2581 are the latest in the string of developments of innovative pumping technologies.

With expertise across the spread of pumping strategies, Welch is best placed to provide the most appropriate solution to any pumping application.

All the pumps across the Welch range benefit from volume manufacture, ensuring highly competitive prices.

A complete range of highly reliable and competitively priced Welch vacuum pumps and systems is available across Europe from ASF Thomas, along with a correspondingly high level of local service and support.