Automatic protective device particularly for high-vacuum apparatus, the device preventing air and oil inroads into chambers to be evacuated

摘要

856,828. Vacuum pumps; high vacuum apparatus. ZEISS JENA, C. VEB. Sept. 25, 1957, No. 30108/57. Classes 8(1) and 71. [Also in Group XXIX] A valve in high vacuum apparatus located between a rough-vacuum pump 2 and a highvacuum pump 3 to prevent pump-sealing oil from the former pump entering the latter pump or the vacuum chamber 25, comprises a main valve 8 controlling a conduit 4 leading to the high-vacuum pump 2, an interconnected vent valve 6 and an adjustable nozzle 7 in the vent passage. On the closure of a switch 11, a motor 12 drives the pump 2 which on reaching a, speed sufficient to reduce the pressure in the valve housing 1 to a value predetermined by the adjustment of the nozzle 7 operates a centrifugal switch 13. The switch 13 then actuates a slow-acting relay 14 to energise a solenoid 15 to move an armature 16 fast with a body 17 rightwardly against a spring 9. The vent valve 6 urged by a spring 20 follows-up the movement of the body 17 and when this valve is seated a face 24 on the body 17 engages a button 22 on the stem 21 of the main valve 8 to unseat the valve 8. In the event of the pump 2 stopping through break down or other reasons the valve 8 will close prior to the opening of the valve 6 and so prevent the entry of oil into the conduit 4.