| 摘要 |
PROBLEM TO BE SOLVED: To provide a reliable static pressure type noncontact gas seal capable of exhibiting a sufficient sealing function regardless of pressure conditions of a sealed gas region.SOLUTION: A static sealing ring 4 is movably held in a seal case 1 by O rings 8 and 9, a back pressure chamber 61 is formed in a sealed state between the seal case 1 and the static sealing ring 4, and seal gas G1 which is prepared by reducing the pressure of gas G in a sealed gas region H by an orifice 52 is supplied into a space between sealing end faces 31 and 41 through a seal gas supply passage 51 of the static sealing ring 4, and thus, opening force Fo for separating the sealing end faces 31 and 41 from each other is generated, and the gas G in the sealed gas region H is introduced into the back pressure chamber 61 through a back pressure introduction passage of the static sealing ring 4, and closing force Fc for approaching the sealing end faces 31 and 41 with each other is generated by the back pressure thus obtained, and by balancing the opening force Fo with the closing force Fc, the sealed gas region H and a non-sealed gas region L are sealed while keeping the sealing end faces 31 and 41 in a noncontact state. |
