Welch Belt-drive vacuum pumps are known world-wide to be reliable and durable in the most demanding applications. The belt drive feature runs the pump at a lower rpm which reduces frictional wear and sound. The reduced friction also keep the oil cool which increases overall vacuum depth. The large oil reservoir dilute contaminates and keeps the internal parts well lubricated. These pumps are constructed of iron and steel (not aluminum), so they last longer than direct drive pumps, but are heavy.
Belt-drive vacuum pump are available in three types: DUOSEAL, CHEMSTAR and CAPTURE.
Chemstar pumps have PTFE coated oil cases and Fluorelastomer gaskets and seals and are especially suited for corrosive gases. Where corrosive vapors or large quantities of condensable vapors are evolved from vacuum processing, a cold trap must be used in the connecting line to the pump. It will help prevent damage to the pump mechanism and reduce oil contamination. The cold trap, immersed in liquid nitrogen or dry ice and acetone. The refrigerant to be used depends upon the freezing point of the contaminants. A variety of cold traps are available from Goldleaf Scientific here
|Ultimate Pressure (Torr)||1x10⁻⁴|
|Free Air Displacement (cfm, LPM)||0.9,25|
|Dimensions, LxWxH, (inches)||12x10x12|
|Oil Type||Welch DirectTorr Gold|