Daniel T Mcdonell, 631057 3Rd St, Dubuque, IA 52001

5832953, Nov 10, 1998

Feb 20, 1996

8/607265

Michael D. Lattner - Dubuque IA
Daniel T. McDonell - Dubuque IA

F16K 3122
F16K 3124
F16K 3134
F16K 4300

137315

An improved overfill shut-off system for a liquid storage tank includes a passage having an inlet end and an outlet end, a valve seat in the passage, a plunger that is movable within the passage for the purpose of engaging the valve seat to impede flow of liquid in the passage, and a guide member for guiding movement of the plunger. The plunger and the guide member are sealed with respect to each other and together define a control space. A first port is defined in the plunger for communicating the control space with an upstream end of the passage, and a second port is defined in the guide member for communicating the control space with a downstream end of the passage. A valve is provided for selectively impeding fluid flow through the second port in response to the level of a float member within the storage tank. When liquid level in the storage tank reaches a predetermined maximum, liquid flowing through the passage will be permitted through the first port, but not through the second port. This creates a hydraulic effect that will expand the control space and extend the plunger to engage the valve seat, thereby preventing overfill of the storage tank.