06468052 is referenced by 65 patents.

A safety device for use in a fluid transfer and/or circulation system of the type which uses a pump to draw water from a reservoir through one or more intake lines each extending from an open end at the reservoir to the pump intake. The safety device connects to the fluid transfer/circulation system and includes a sensor, a triggering mechanism, and a vacuum breaker. When the pump is operating, the sensor monitors one or more conditions of the system. When one or more of the monitored conditions deviates outside of a normal operational range, as a result of an obstruction of any one or more of the open ends of the intake lines, the triggering mechanism triggers the vacuum breaker to eliminate negative pressure in the system by introducing air from atmosphere into the intake lines, thereby removing suction at the open ends of the intake lines. The safety device may further activate warning devices including audible and visible alarms to indicate that the system has been deactivated.

Title
Vacuum relief device for fluid transfer and circulation systems
Application Number
9/756378
Publication Number
6468052 (B2)
Application Date
January 8, 2001
Publication Date
October 22, 2002
Inventor
Mark Fritze
558 Lakeside Cir., Sunrise
FL, US
Paul C McKain
3300 NW. 97th Ave., Sunrise
FL, US
Agent
Robert M Downey P A
US
Assignee
Mark Fritze
FL, US
Paul C McKain
FL, US
Robert M Downey
FL, US
IPC
F04B 49/00
View Original Source