Patent ID: 6705339
Filing Date: 2004-03-16
Classification: E03B,F16K,Y10T

Abstract:
A safety check unit for use in a liquid distribution system having a pump and piping downstream of the pump for distributing pumped liquid to the liquid distribution system, wherein the pump intakes a liquid at an intake pressure and outputs the liquid to the liquid distribution system at an output pressure which is greater than the intake pressure, and wherein absent action of the pump, liquid in the system exerts a back-pressure at the pump which is greater than the intake pressure, the safety check unit arranged for placement intermediate the liquid distribution system and the pump, and in liquid communication therewith, comprisinga liquid checking portion, for checking liquid when back-flowing from the system toward the pump, having an inlet port in liquid communication with the pump, an outlet port in liquid communication with the distribution system, an internal chamber intermediate said ports, and a closing member disposed in said internal chamber for preventing back-flowing of the liquid; a surge relief portion, communicating directly with said internal chamber, for relieving liquid and reducing liquid pressure in the liquid distribution system when the liquid pressure in said internal chamber is a preselected pressure which is greater than an operating output pressure of the pump; an air input portion, communicating directly with said internal chamber, for providing air to the liquid distribution system when said internal chamber is at least partially void of liquid and a pressure in the void is below atmospheric pressure; and an air release portion, communicating directly with said internal chamber, for releasing air from the liquid distribution system when air is in said internal chamber at a pressure above atmospheric pressure.