| 摘要 |
A valve assembly is provided that prevents overfilling of vessels, such as tanks used to hold liquified gas, beyond a predetermined maximum level. Preferably, the valve assembly is for use with an LP tank attached at the bottom of a service valve thereof. The valve assembly has a valve member controlled for shifting by a float assembly that rises and falls with the fluid level in the tank. The float assembly keeps the valve member removed from the flow of fluid through the valve housing during tank filling operations in a chamber of a diverter member until the maximum fill level is approached when the float assembly allows the valve member to begin to shift into a blocking position projecting from the diverter member restricting flow into the tank and eventually cutting it off when the maximum fill level is attained. Flow paths defined by recessed channels formed on the exterior of the diverter member direct incoming fluid flow around the valve member in the diverter member chamber during tank filling operations. A port of the housing is below the flow paths which direct fluid through the port during tank filling operations until the valve member shifts to its blocking position. The valve assembly also allows for outgoing flow therethrough for unloading of the tank when opened to ambient by shifting of the valve member off from its seat in the blocking position due to the pressure differential in the tank interior versus the lower ambient pressures exterior of the tank. As the tank is unloaded, the float assembly lowers pivoting cam member thereof to lift valve stem causing the valve member to shift from between the flow paths and port allowing fluid to flow out from the tank. |
