| 摘要 |
A reciprocating pneumatically operated pump apparatus 10 for use in a post-mix syrup dispensing operation has a fail-safe pump reversing system which includes a valve actuating member 17 for reversing the valve mechanism 40 which controls the reciprocating pump action. An overcenter, snap-acting mechanism is provided to preclude the valve actuating member 17 from sticking in a central position. The snap-acting mechanism is configured to substantially preclude bearing load in a direction transversely of the direction of movement of the valve actuating member 17. The pump housing 11 is of molded plastic with all fluid passages and pump connections formed therein. The output valves of the pump are positioned at the highest point in the discharge sections 28, 29 of the piston chambers to minimize the accumulation of air bubbles. <IMAGE> |
