| 摘要 |
PURPOSE:To improve strength and durability of a metal seal part, by providing a seal material, having a spring contained in the annular seal main unit consisting of an aluminum alloy, to be fitted to an annular groove in a gate valve plate. CONSTITUTION:A gate valve plate 4 is pressed toward an internal surface surrounding an opening part in a valve case 1, and the gate valve plate 4 provides on its surface an annular groove 5 comprising a cylindrical surface almost at a right angle to the surface of the gate valve plate and a clipped conical surface positioned inside the cylindrical surface. An annular metal seal material 9, consisting of an aluminum alloy annular seal main unit 7 with a hollow circular section partly being cut and a pressure resisting spiral spring 8 fitted to the housed in the unit 7, is forcedly fitted by pressure in the cylindrical surface in the annular groove 5. A hardening processed layer consisting of a titanium carbide layer is formed on a mirror worked internal surfsce of the valve case 1 and the annular groove 5. |
