An improved fuel dispensing nozzle of significantly reduced size and weight has a single diaphragm that provides the vapor regulating function as well as providing the excess pressure and excess vacuum shut-off functions. Improved shut-off function is obtained by ensuring that chamber pressure is the...http://www.google.com.tw/patents/US5174346?utm_source=gb-gplus-share專利 US5174346 - Fuel dispensing nozzle
