| 摘要 |
PURPOSE:To absorb a fine and short period variation in pressure and enable a pressure within a furnace to be uniformed by a method wherein when a pressure within the furnace is increased, a space within the furnace is expanded together with an expandable or contractable member and in turn when the pressure within the furnace is decreased, the space is reduced together with the expandable or contractable member. CONSTITUTION:Since a space part V communicates with a space within a furnace, as a pressure P1 within the furnace is increased, this increased pressure is transmitted to the space V so as to expand an expandable or contractable member 42 in an outward direction and then the space part V is expanded. The increased pressure within the furnace is accommodated by the expansion of this space part V and the pressure with the furnace is kept at a pressure P1 balancing with an out-of-furnace pressure P2. As the pressure within the furnace is decreased, this decreased variation pressure is absorbed by a reduced volume of the space V, resulting in that the pressure within the furnace is kept at the pressure P1 balancing with the out-of-furnace pressure P2. With this arrangement, the difference between the pressure within the furnace P1 and the space pressure P2 of the out-of-furnace is kept within a range of about several mmH2O under a normal condition. |
