| 摘要 |
PURPOSE:To keep the sealing function by a gland packing for a long time by interposing between the gland packing and a packing box a tightening means to press the gland packing toward the outer packing. CONSTITUTION:When sealing is made between the outer circumferential surface of a valve stem 9 and the inside surface of a packing box 21, an elasticity energizing means 26 presses an inner packing part 23 and a center packing part 24 to the mutually opposite direction along the axial direction of the valve stem 9, and the center packing part 24 is expanded in the radial direction of the valve stem. Thus, the sealability is not damaged even when the inner packing part 23 and the outer packing part 25 are worn. When the sealability of the inner packing part 23 and the center packing part 24 is damaged due to long use nd the fluid is leaked also from the outer packing part 25, the pressing force of a tightening means 34 is increased, the outer packing part 25 is pressed in the axial direction of the valve stem 9 through a packing gland 23, and the outer packing part 25 is expanded in the radial direction of the valve stem 9 to restore the sealability. |
