Chemvac presents 'non polluting' vacuum circuit sets
15 Jan 2000
The ever-tightening anti-pollution legislation to protect watercourses, combined with some process companies' own environmentally friendly inclinations mean a reappraisal of closed circuit vacuum producing systems, claims supplier Chemvac pumps.
In the closed circuit system the sealant, usually water, rises in temperature as it passes through the vacuum pump. Heat, generated by compression and the latent heat of condensation of vapours, has to be removed from the circuit to ensure a constant sealant temperature. The system achieves this with a plate type heat exchanger made in 316 stainless steel.
The usual coolant is water that is recirculated from an evaporative cooling tower. Typically, the summer temperature of such water in the UK is no more than 25 degrees C, so sealant water temperature to the liquid ring vacuum pump is normally about 28 degrees C.
This in turn reduces pump capacity and maximum absolute suction pressure but is still suitable for plants operating above 50mbar absolute. Otherwise, suction pressure must be boosted by air ejectors or Roots type mechanical boosters. Ultimately, suction pressures better than 0.1mbar are quite achieveable.
Such systems available from Chemvac with various automated controls. Materials of construction can be selected from various steels and alloys and systems can be easily flame-proofed.
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