| 摘要 |
The present invention provides a static pressure type non-contact gas seal which, even when supply of seal gas 6 to the space between sealing end surfaces 3 a and 4 a has stopped unexpectedly, can be safely used with no possibility that the sealing end surfaces 3 a and 4 a collide severely against each other and consequently the sealing end surfaces 3 a and 4 a are damaged or destructed. In this static pressure type non-contact gas seal, the seal gas 6 is supplied to the space between the sealing end surfaces 3 a and 4 a from a seal gas passage 5, thereby generating an opening force that acts on the stationary sealing ring 4 in a direction that the space between the sealing end surfaces 3 a and 4 a is opened. An annular-spaced back pressure chamber 25 blocked by two O-rings 12 and 13 is formed between the facing peripheral surfaces of a seal case 1 and the stationary sealing ring 4, to introduce the seal gas 6 to be supplied to the seal gas passage 5 into the back pressure chamber 25, thereby generating a closing force that maintain the balance with the opening force, as a back pressure acting on the stationary sealing ring 4. A spring is not used as a means for generating the closing force.
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