| 摘要 |
PURPOSE:To accomplish smooth operation by providing a balance port to balance pressure in the vertical direction and in the peripheral direction of a rotary valve rod of a rotary valve. CONSTITUTION:An introduction passage 33 of a rotary valve rod 32 is connected to a space between the shoulder portion of the central portion of the rotary valve rod 32 and an upper cover 34. The outside diameter (d) of the upper end portion of the rotary valve rod, the outside diameter D of the central portion and the outside diameter (d') of the lower end portion are determined to balance pressure in the vertical direction. The first and second balance ports 41, 42 are disposed on the rotary valve rod on opposite side of supply passages 39, 40. Distances l1, l2 from the supply passages 39, 40 to the respective ports 41, 42 are determined to balance pressure working upon the respective ports and passages. In this arrangement, the pressure of the rotary valve rod 32 is balanced in the vertical and peripheral directions. |
