| 摘要 |
<p>770,100. Air-blast switches. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. June 3, 1955 [June 4, 1954], No. 15915/55. Class 38(5) In an air-blast circuit-breaker having contacts 1, 2 arranged in a compressed air container 3 and opened by the delivery of compressed air to an operating member 15 which opens a channel 19 between its. housing 5 and the atmosphere, thus permitting the pressure in the container 3 to open contact 2, the contact 2 is provided with a disc 7 which, when brought into contact with member 15 forms a space which communicates with the atmosphere through channels 28, 29 and 19 and pneumatically couples the contact 2 with the member 15 so that when, after a delay, the member 15 is restored to its original position, the contact 2 moves with it to remain open'until the supply of operating air is interrupted, when the space between the disc 7 and the member 15 is cut off from the atmosphere and brought into communication with the pressure within the housing 5 and the contact 2 is closed by spring 31. The operating air is delivered along pipe 12 to raise piston 11 and open channels 19, causing the pressure within housing 5 to fall. Compressed air in container 3 then moves the contact 2 and disc 7 down to seat against member 15. Compressed air also flows through channel 13 to the upper side of piston 11 so that when the pressure above the piston has risen, the pressure in container 3 causes the contact 2 and disc 7 to push the member 15 and piston 11 downwards and re-close the channels 19. In closing the circuit-breaker, pipe 12 is evacuated, lowering membrane 22 and valve 25 to allow compressed air to flow from housing 5 through channels 26 and 28. The pressure on the lower side of disc 7 then rises to equal that on the upper side and the disc is raised by spring 31 to close the contacts.</p> |
