Improvements in and relating to oil-sealed rotary mechanical vacuum pumps

摘要

1,063,068. Rotary vacuum-pumps. BALZERS PATENT-UND LIZENZ-ANSTALT. Oct. 4, 1965 [Oct. 8, 1964], No. 41921/65. Heading F1F. In a rotary vacuum-pump of the radial-vane type, atmospheric air for ballasting and noisereducing purposes is admitted at a controlled rate to a compression chamber or working space (9), Figs. 1 and 2 (not shown), through a vertical pipe (10) and a port (11), the uppermost end of the pipe being situated above the surface level (8) of sealing oil lying in a reservoir or container (13) whereas the lowermost end includes a slot (16) and engages with a spring-biased ball (14) to effect throttling of said air. A gap (17) adjacent the lower side of the ball can be varied by changing the depth of engagement of the pipe with a screwthreaded bore (12). A proportion of oil in the chamber (9) is ejected through the port (11) to cleanse the gap (17) and the slot (16) while air is expelled through a port (6) controlled by a non- return valve (7) in the reservoir (13). Alternatively, the lowermost end of the pipe (10) engages with a disc (18), Fig. 3 (not shown), containing a flow-restricting orifice.