Automatic flow cut-off for filling tanks - float valve balances pressures on diaphragm in main valve

摘要

A tank filling system includes a supply valve (103) the pressure lifting a membrance (125) and opening the valve seat (127) letting liquid flow through the inlet tube (117). A small part of the flow passes through an orifice (140) and through a small bore tube and valve to the tank. When the liquid level reaches a given value, a float closes the valve at the tank and the flow through the orifice (140) fills a secondary chamber (141) and the space (143) above the membrane. The valve (103) thus closes and the flow stops. To empty the tubes a relief valve (109) is opened and the liquid drains through a small tube (159). If the liquid level exceeds a maximum value, a float device at the end of the small tube (159) prevents the pipes being drained.