Patent ID: 7814930
Filing Date: 2010-10-19
Classification: F16K,Y10T

Abstract:
1. A mechanism for automatically controlling the addition of liquid to a tank wherein a liquid replenishing system is used to selectively deliver liquid to the tank, the liquid replenishing system having a pressure source, which generates at least one of liquid pressure and pneumatic pressure, said mechanism comprising: a container for mounting in the tank, which container includes an inlet for introducing liquid into said container, at least when the level of liquid in the tank exceeds a lowermost level of said inlet, said container further including an outlet formed below said inlet; a discharge valve operably mounted to the container for alternately closing and opening said outlet; a lower float for closing said discharge valve when liquid is at or above a predetermined level in said tank and for opening said discharge valve when the liquid in said tank is below said predetermined level to discharge liquid from said container; a pressure inlet in said container for connecting communicably to the pressure source of the liquid replenishing system; a pressure relief valve alternatable between open and closed conditions for respectively opening and closing said pressure inlet to respectively reduce and increase the pressure generated by the pressure source of the liquid replenishing mechanism; and an upper float mounted within said container for maintaining said pressure relief valve in one of said open and closed conditions when the liquid in said container is at or above a threshold level and for maintaining said pressure relief valve in the other of said open and closed conditions when the liquid in said container is below said threshold level, whereby the pressure generated by the pressure source is respectively increased and when the pressure relief valve is closed and decreased when the pressure relief valve is opened.