| 摘要 |
959,461. Liquid and gaseous seals. COMPAGNIE ELECTRO-MECANIQUE. Feb. 28, 1961 [March 1, 1960], No. 7249/61. Heading F2B. The shaft 2 of a gas blower 1 is sealed by means of an oil seal device 6 in combination with a gaseous seal device 7 which is fed with a sealing gas having a density greater than that of the gas circulating through the blower, a radial pressure-gradient being established in the gaseous seal device by means acting on the sealing gas for isolating completely, under normal operating conditions, the gas of the blower from the oil vapours likely to escape from the oil seal device and for detecting, under abnormal operating conditions, any oil leakage towards the blower. The shaft 2 is supported horizontally in bearings 3, 4 and carries an impeller 1a The sealing device 7 consists of members 10, 11 secured by tie-rods 14 and constituting a chamber in which a disc 9 mounted on the shaft 2 revolves and subjects the sealing gas to centrifugal force so that a difference in pressure is produced radially in the chamber between the base and the periphery of the disc. The sealing gas, which may be different from that in the blower, or may be the same gas previously cooled in a heatexchanger 15, is fed through a pipe 17, a chamber 18 and a duct 19, which may all be heat-insulated or jacketed, to the chamber of the sealing device 7 which may be cooled. Oil is circulated under pressure in the oil seal device 6 and returns through a chamber 27 and a duct 24 to a tank 25 kept under pressure by an automatic drain valve 26. The duct 24 is provided with a discharge valve 23 controlled by a regulator 22 connected to the chamber 7 through ducts 20, 21 opening respectively in front of the base and periphery of the disc 9. A regulator 28 actuating an alarm or corrector device 29 is connected to the duct 20 and, through a duct 20a to the chamber 27. A labyrinth packing 8 is provided between the sealing devices 6, 7. In normal operation oil flow in the sealing device 6 is adjusted by the valve 26 so that the pressure in the chamber 27 is approximately equal to that in the blower. If due to a rapid pressure drop in the blower or to faulty operation of valve 26 oil is drawn from the chamber 27 into the chamber 7, the consequent increase in pressure differential in the latter will cause the regulator 22 to open the valve 23 until the oil is forced back from the chamber 7 into the chamber 27. Should the pressure in the chamber 27 drop abnormally due to faulty operation of valve 26, the consequent pressure differential set up between either side of the packing 8 due to passage of gas from the blower to the chamber 27 will cause regulator 28 to actuate the alarm or device 29 with a view to adjust valve 26. French Specification 1,147,053 is referred to. |
