HT Diffusion Pumps

These pumps are designed to give high throughput (pressure multiplied by pumping speed) at 4 x 10-3 mbar making them ideal for industrial processes that evolve large quantities of gases. Their highcritical backing pressure means that they are more tolerant to suddenincreases in load. They are particularly suitable for large coating systems and furnaces.

All Edwards vapour diffusion pumps are fully fractionating. Thismeans that

volatile components are fed to the lower stages of the vapour pump and the vapour fed to the inlet stage is stripped of thesefractions and this improves the ultimate vacuum performance of thepump. Conduction cooled baffles above the pump help to preventpump fluid migration into the vacuum system, which would preventthe pump achieving its ultimate vacuum. Baffles also ensure thatbackstreaming is minimised.

The outgassing from the system, its leak tightness, the vapourpressure of the pump fluid and the number of joints and elastomersused for seals all contribute to the pump down time and ultimatevacuum achievable. Ultimate vacuum is a function of the vapourpressure of the pump fluid selected, at a particular temperature, andin most industrial applications the pump’s throughput at a particularpressure is more important than obtaining a very high ultimatevacuum. For these reasons we have elected not to quote an ultimatevacuum for our industrial vapour diffusion pumps, since it would notprovide a useful measure of their performance.

By combining Edwards vapour diffusion pumps with either our GVseries dry pump combinations or our oil-sealed rotary pumpcombinations fast pump-down and process times are achievable. Ourapplications specialists are able to recommend suitable pumpcombinations to meet specific process requirements.

Edwards HT10 (ANSI10/ISO320 inlet), HT16B (ANSI16/ISO5000 inlet) and HT20B (ANSI20/ISO630 inlet) diffusion pump is designed for all light and heavyduty industrial applications. The robust construction gives high pumping speed at highpressure. The cast and machined aluminium interior provides consistent performance, whilethe stainless steel body prevents corrosion and ensures process cleanliness. These pumps are designed to give a high throughput (pressure multiplied by pumping speed) at 4 × 10-3 mbar making them ideal for industrial processes that involve large quantities of gases.