Anti-contaminant diaphragm valve

Abstract

The solenoid plunger normally closes the center vent hole in the diaphragm so inlet pressure is applied through the bleed hole to the space above the diaphragm resulting in enough pressure to close the diaphragm on the valve seat. When the solenoid is actuated, the plunger is lifted, allowing water to flow through the vent faster than it can flow through the bleed hole. This lowers the pressure above the diaphragm so inlet pressure can move the diaphragm from the seat and full flow can take place. The bleed hole is quite small. To prevent entrained particles from reaching and plugging the bleed hole, an arcuate groove having a width less than the bleed hole diameter is molded into the diaphragm to trap particles in the groove and prevent the particles from reaching and closing the bleed hole.

We claim: 
     
       1. A solenoid valve comprising a valve body having an annular inlet and an outlet centrally located relative to the inlet,   a diaphragm mounted in the body overlying both the inlet and the outlet,   a valve seat between the inlet and the outlet.[.and.]. .Iadd., .Iaddend.   .Iadd.said diaphragm .Iaddend.having a resilient face adapted to close on said seat,   a rigid insert molded in the diaphragm,   a central valve hole through the diaphragm and insert,   a solenoid assembly including a watertight plunger guide and a coil surrounding the guide, the guide cooperating with the diaphragm to define a chamber the contents of which may flow through the vent hole when the hole is open,     a plunger slidable in the guide and having a valve portion normally closing the vent hole but movable upon energization of said coil to open the vent hole,   a bleed hole in said insert outside the portion overlying said valve seat,   a groove in said resilient face communicating with said bleed hole whereby fluid may flow from the inlet through the groove into the bleed hole and then into said chamber,   the width of said groove being less than the diameter of the bleed hole whereby entrained particles which pass through the groove will pass through the bleed hole while larger particles are rejected or lodge in the groove.   
     
     
       2. A solenoid valve according to claim 1 including a diverging passage in said resilient face leading from the bottom of the groove to the bleed hole with the large end of the passage being larger than the bleed hole. 
     
     
       3. A solenoid valve according to claim 1 in which the groove is arcuate with its mean diameter generally intersecting the axis of said bleed hole. 
     
     
       4. A solenoid valve according to claim 1 in which the depth of the groove is greater than the width. .Iadd. 5. A solenoid valve comprising a valve body having an annular inlet and an outlet centrally located relative to the inlet,   a valve seat between the inlet and the outlet,   a diaphragm mounted in the body overlying both the inlet and the outlet, said diaphragm having a substantially inflexible central portion of greater diameter than the valve seat surrounded by an annular flexible portion, the central portion having resilient face adapted to close on said seat,   a cental vent hole through the diaphragm,   a solenoid assembly including a watertight plunger guide and a coil surrounding the guide, the guide cooperating with the diaphragm to define a chamber the contents of which may flow through the vent hole when the hole is open,     a plunger slidable in the guide and having a valve portion normally closing the vent hole but movable upon energization of said coil to open the vent hole,   a bleed hole in said central portion outside the portion overlying said valve seat,   a groove in said resilient face communicating with said bleed hole whereby fluid may flow from the inlet through the groove into the bleed hole and then into said chamber,   the width of said groove being less than the diameter of the bleed hole whereby entrained particles which pass through the groove will pass through the bleed hole while larger particles are rejected or lodge in the groove. .Iaddend.