STATIC PRESSURE TYPE NON-CONTACT GAS SEAL

摘要

PROBLEM TO BE SOLVED: To prevent composition of gas to be sealed with mixture of seal gas from being varied.SOLUTION: This invention relates to a static pressure type non-contact gas seal comprising: an annular rotary seal ring attached to a rotary shaft in such a way that it can be integrally rotated with the shaft; an annular static seal ring fixed to a casing and axially opposing against the rotary seal ring; a gas supply passage for supplying seal gas between the seal surface of the static seal ring and the seal surface of the rotary seal ring; and a resilient member for biasing one of the static seal ring and the rotary seal ring toward the other, and partitioning into a first space filled with gas to be sealed on one side in the axial direction and a second space on the other side in the axial direction while sandwiching the seal surfaces of respective seal rings. There is provided a gas supply device for connecting the first space with the gas supply passage and supplying the gas to be sealed in the first space between the seal surfaces of respective seal rings as the seal gas.