| 摘要 |
PURPOSE:To permit the valve function to be developed sufficiently for both of the positive and the negative pressure in a vessel by permitting both of negative and position pressure valves to be operated by means of a spring. CONSTITUTION:When a positive pressure is formed in a vessel, the pressure acts onto a movable seal plate 7, then a spring 2 is compressed to raise the plate 7. Accordingly, the gas in the vessel is discharged outside. When a negative pressurs is formed in the vessel, the outside air pressure is applied onto a valve member 6 and the movable seal plate 7, and the spring 2 is compressed to lower the valve member 6 together with a spring retain plate 3. Thus, a negative pressure valve 61b is opened to introduce the outside air into the vessel. |
