| 摘要 |
PURPOSE: To provide a shaft seal device without leakage for a screw feeder to carry an object in the shaft direction. CONSTITUTION: A screw feeder is provided with following seal boxes; a first seal box 1, in the tip of which is firmly fixed to an outer cylinder 06, and which is supported on base plate 021 and receives a first gland packing 2 on the inner circumferential surface; a second seal box 3 which allows longitudinal movement made by a spring member 4 and is connected to a rear end of the first seal box 1, receives a second gland packing 5 on the inner circumferential surface, and is provided with a buffer gas chamber 6 for supplying a incombustible gas of higher pressure than that inside of the outer cylinder 06, in the intermediate part between the first and second gland packings 2, 5; and a third seal box 8 which allows longitudinal movement made by a spring member 9 and is connected to the second seal box 3, receives a third gland packing 10 on the inner circumferential surface, and is provided with a seal gas chamber 11 for supplying a seal gas such as air of higher pressure than that of the exterior and lower pressure than that of the incombustible gas, in the intermediate part between the second and third gland packings 5, 10. |
