A solenoid valve includes a flexible diaphragm and ball to control hydraulic or pneumatic fluid flow. The diaphragm provides an essential part of a complete seal which prevents contaminants from adversely affecting operation of the valve. The diaphragm and ball are formed into a single impervious integral...http://www.google.ca/patents/US5046701?utm_source=gb-gplus-sharePatent US5046701 - Molded ball/seal
