Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
225 words
For use with a liquid system having a reservoir, a device for detecting when a liquid in the reservoir falls below a predetermined level comprising: a housing defining a chamber, means for fluidly connecting said housing chamber to said reservoir, a plate having a port, said plate dividing said housing chamber into an upper elongated chamber and lower chamber, a piston slidably mounted in said upper chamber and movable between a first position in which said piston is adjacent said plate and a second position in which said piston is adjacent an end of said upper chamber spaced from said plate, means for urging said piston towards said first position, means for continuously cyclically urging said piston towards said second position, said cyclical urging means comprising a cyclical vacuum source continuously fluidly connected to said end of said upper chamber, means for indicating when said piston is at said second position, and means for closing said port when said liquid is at or above said predetermined level so that with said port closed, travel of said piston toward said second position creates a partial vacuum in said lower chamber which prevents said piston from reaching said second position and so that, when said liquid is below said predetermined level, said port remains open to prevent the formation of a partial vacuum in said lower chamber.
Claim 2
Dependent Claim
225 words
For use with a liquid system having a reservoir, a device for detecting when a liquid in the reservoir falls below a predetermined level comprising: a housing defining a chamber, means for fluidly connecting said housing chamber to said reservoir, a plate having a port, said plate dividing said housing chamber into an upper elongated chamber and lower chamber, a piston slidably mounted in said upper chamber and movable between a first position in which said piston is adjacent said plate and a second position in which said piston is adjacent an end of said upper chamber spaced from said plate, means for urging said piston towards said first position, means for continuously cyclically urging said piston towards said second position, said cyclical urging means comprising a cyclical vacuum source continuously fluidly connected to said end of said upper chamber, means for indicating when said piston is at said second position, and means for closing said port when said liquid is at or above said predetermined level so that with said port closed, travel of said piston toward said second position creates a partial vacuum in said lower chamber which prevents said piston from reaching said second position and so that, when said liquid is below said predetermined level, said port remains open to prevent the formation of a partial vacuum in said lower chamber.
Claim 3
Dependent Claim
63 words
The device as defined in claim 1 wherein said closing means comprises valve means contained within said lower chamber and an elongated tube open at each end, a first end of said tube secured to said housing and open to said lower chamber, said tube insertable into said reservoir so that a second end of said tube is positioned at said predetermined level.
Claim 4
Dependent Claim
27 words
The device as defined in claim 2 wherein said valve means comprises a liquid float which closes said port when said liquid is above said predetermined level.
Claim 5
Dependent Claim
33 words
The device as defined in claim 1 wherein said means for urging said piston comprises a spring contained within said upper chamber and compressed between said piston and one end of said housing.
Claim 6
Dependent Claim
33 words
The device as defined in claim 1 wherein said indicating means comprises an electrical switch and means carried by said piston for actuating said switch when said piston is in said second position.
Claim 7
Dependent Claim
56 words
The device as defined in claim 5 wherein said switch comprises a pair of spaced electrical contacs secured to said housing within said upper chamber at said end of the upper chamber, wherein said means carried by said piston comprises an electrically conductive member which engages said contacts when said piston is in said second position.
Claim 8
Dependent Claim
29 words
The device as defined in claim 2 and comprising a dip stick for manual reading of the level of the reservoir secured to said second end of said tube.
Claim 9
Dependent Claim
26 words
The device as defined in claim 1 and comprising a vacuum delay valve fluidly connected in series between said cyclical vacuum source and said upper chamber.
Claim 10
Dependent Claim
42 words
The device as defined in claim 2 and comprising means for maintaining fluid connection between said lower chamber and said reservoir whereby said lower chamber remains in communication with said liquid during a mometary drop of the liquid below said predetermined level.
Claim 11
Dependent Claim
35 words
The device as defined in claim 9 wherein said maintaining means comprises a container enclosing the lower end of the tube, said container secured to said tube, and a leak valve open to said container.
Claim 12
Dependent Claim
24 words
The device as defined in claim 2 wherein said tube comprises an extruded plastic section having hollow conduit portion and containing a structural wire.