| 摘要 |
A valve, 100, has a valve body, 101, with a recess 115 engaged by a movable threaded plug 116. A valve control member, 117 in the form of a ball is positioned on the projecting end 118 of the plug 116 so that its upper surface projects into the valve chamber 113 by a pre-determined amount. In its use with a vehicle fuel system, the valve 100 would have its outlet connector 103 connected to the vehicle engine and its inlet 114 connected to the fuel tank. In filling the fuel tank the ball 117 is unable to prevent the flow of the fuel, such as compressed natural gas. In the event of a rupture in a fuel line, excess flow of fuel from the fuel tank through the inlet 114 will create a fluid flow turbulence within the chamber 113, which turbulence is enhanced by the presence of a projection 152 extending into the chamber 113. The degree of exposure of the ball 117 within the chamber 113 is sufficient at that pre-determined rate of excess fluid flow for the turbulence to lift the ball 117 and position it against the ball seat 107 to prevent or limit further fuel flow. Automatic re-setting of the valve 100 can be achieved if the ball seat 107 permits some fuel flow to continue. Other embodiments of the invention provide for the re-setting of the valve by manual re-setting or by provision of a specific by-pass path. |
