Self-purging proportioning pump for corrosive liquids

Claim 1

A SELF-PURGING PROPORTIONING FEED PUMP COMPRISING, IN COMBINATION, A HOUSING HAVING THEREIN A PUMPING CHAMBER AND A HYDRAULIC CHAMBER, A FLEXIBLE DIAPHRAGM FORMING AT LEAST A PORTION OF A WALL SEPARATING THE CHAMBERS AND ADAPTED TO FLEX FROM A NORMAL POSITION OUTWARDLY INTO THE PUMPING CHAMEBR UNDER PRESSURE OF HYDRAULIC FLUID IN THE HYDRAULIC CHAMBER; A FLUID PORT AT THE HIGHEST POINT OF THE HYDRAULIC CHAMBER, PULSING MEANS IN FLUID CONNECTING WITH THE FLUID PORT FOR CYCLICALLY SUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO THE HYDRAULIC CHAMBER AND FOR EXHAUSING HYDRAULIC FLUID FROM THE HYDRAULIC CHAMBER, VENT MEANS FOR VENTING THE HYDRAULIC SYSTEM TO THE ATMOSPHERE ONLY DURING THE EXHAUST PORTION OF THE CYCLE, DIAPHRAGM BIAS MEANS WITHIN THE HYDRAULIC CHAMBER FOR RETURNING THE DIAPHRAGM TO A NORMAL POSITION DURING THE EXHAUST PORTION OF THE CYCLE, AND FLUID INLET AND OUTLET CONNECTIONS IN THE PUMPING CHAMBER FOR SUPPLYING FLUID TO BE PUMPED AND DELIVERING PUMPED FLUID BY FLEXING PULSATION OF THE DIAPHRAGM.