|
PatentVote.com: Vote on your favourite invention!
|
|
 |
Title: Apparatus for checking the level of liquid in containers
Claims: I claim: 1. Apparatus for checking the presence of liquid at a predetermined level in a cntainer, the apparatus comprising, in combination: valve means disposed externally of said container; manually operable suction means to generate vacuum pressure and connected to said valve means; elongate duct means having constriction means between a first end portion extending into said container to define an opening in said duct means at said predetermined level and a second end portion connected to said valve means, said valve means being actuable by said suction means to close said duct means only on liquid being present at said level; and indicator means responsive to the closure of said duct means by said valve means to indicate the presence of liquid at said level. 2. Apparatus as defined in claim 1, wherein said cnstriction means comprises a portion of said duct means, said portion having an internal diameter of between 1 and 4 millimeters. 3. Apparatus as defined in claim 2, wherein said internal diameter is between 1.5 2 millimeters. 4. Apparatus as defined in claim 1, wherein said valve means comprises a housing and a valve element movable relative to said housing between an open position and a closed position, and biassing means to resiliently urge said element towards said open position, said valve element being moved into said closed position when suction pressure generated by said suction means exceeds the force exerted on said element by said biassing means. 5. Apparatus as defined in claim 4, wherein said biassing means is adjustable to pre-set said force exerted on said element by said biassing means. 6. Apparatus as defined in claim 4, wherein a portion of said valve housing defines a concave seating surface and said movable valve element comprises a resilient diaphragm disposed in mutually facing relationship with said seating surface, said seating surface having a first orifice communicating with said duct means and a second orifice communicating with said suction means, said diaphragm contacting said seating surface to close each of said orifices when said diaphragm is in said closed position. 7. Apparatus as defined in claim 6, wherein said diaphragm surmounts said portion of said housing, an edge portion of said diaphragm being mounted in cntact with said housing portion to seal the periphery of said concave seating surface. 8. Apparatus as defined in claim 4, wherein said housing defines a cylindrical valve chamber bounded at one end by a first end wall having a ventilator passage therein and bounded at the other end by a second end wall, said movable valve element comprising a piston slidably disposed in said cylindrical valve chamber and resiliently urged by spring means against said first end wall, said second end wall carrying valve seating means projecting therefrom and provided with a passage communicating with said suction means, said chamber communicating with said duct means and said piston being urged against said seating in the closed condition of said valve element. 9. Apparatus as defined in claim 1, wherein said valve means is mounted directly on the outer wall of said container. 10. Apparatus as defined in claim 4, wherein said suction means comprises a pump housing and at least part of said valve housing is integral with at least part of said pump housing. 11. Apparatus as defined in claim 1, wherein said suction means comprises a suction pump provided with a housing defining a first cylindrical cavity, a first piston slidably disposed in said first cylindrical cavity, first spring means resiliently urging said first piston towards one end wall of said first cylindrical cavity, a hollow piston rod having one end portion thereof connected to said first piston, a handle connected to the other end portion of said hollow piston rod, a second piston slidably mounted in said hollow piston rod to define one end wall of a second cylindrical cavity communicating with the low pressure of said first cylindrical cavity, second spring means diposed in said second cylindrical cavity to urge said second piston therealong, said second piston being operatively associated with said indicator means. 12. Apparatus as defined in claim 11, wherein said indicator means comprises a pin connected to said second piston and slidably guided in a bore through said handle. 13. Apparatus as defined in claim 11, wherein a portion of the peripheral wall of said second cylindrical cavity in the vicinity of said second spring means defines a groove to by-pass said second piston when the latter is disposed opposite said groove. 14. Apparatus as defined in claim 13, wherein said indicator means is actuable in response to air flowing through said groove towards the low pressure side of said first cylindrical cavity. 15. Apparatus as defined in claim 1, wherein said suction means comprises a suction pump provided with a housing defining a cylindrical cavity, a piston slidably disposed in said cylindrical cavity, spring means resiliently urging said piston towards one end wall of said cylindrical cavity, a hollow piston rod having one end portion thereof connected to said piston, a hollow handle connected to the other end portion of said hollow piston rod, a pushrod slidably guided in the bore of said hollow piston rod and in the bore of said hollow handle to project into a further cavity defined in said hollow handle and communicating with the suction side of said cylindrical cavity, an elastic membrane enclosing said further cavity and selectively engageable with the projecting end portion of said push-rod, said piston at the end of its suction stroke permitting communication between the suction side of said cylindrical cavity and the atmosphere via a ventilator passage in the peripheral wall of said cylindrical cavity, said membrane having an outer stable position into which said membrane is pushed by engagement with said projecting end portion of said push-rod when said piston abuts against said one end wall of said cylindrical cavity, and said membrane having an inner stable position into which it snaps when the suction pressure generated in the low pressure side of said cylindrical cavity attains a predetermined value. 16. Apparatus as defined in claim 15, wherein the external surface of said elastic membrane defines a plurality of grooves therein. 17. Apparatus as defined in claim 16, wherein the groove portions of said external surface of said membrane are of a colour different from that of other surface portions of said external surface. 18. Apparatus as defined in claim 1, wherein said one end portion of said elongate duct means is of larger internal cross-sectional area that the other portion of said duct means. 19. Apparatus as defined as in claim 1, wherein one longitudinal wall portion of said enlarged end portion of said duct means is longer than a longitudinal wall portion thereof opposite said one longitudinal wall portion, whereby the end face of said enlarged end portion defining said opening is inclined to the horizontal. 20. Apparatus as defined in claim 19, wherein a valve seating is provided at the transition between said enlarged end portion of said duct means and said other portion of said duct means, and wherein a ball is provided in said enlarged end portion, said ball having a specific gravity greater than that of said liquid and a diameter such that -- on said liquid being present at said level when said suction means is actuated -- said ball is urged against said valve seating to close said duct means, said ball being retained in said enlarged end portion by a prong projecting into the bore of said enlarged end portion in the vicinity of said opening, said prong being so inclined as to direct said ball against said longer longitudinal wall portion of said enlarged end portion. 21. Apparatus as defined in claim 20, wherein said prong comprises a tongue portion stamped-out of an edge portion the shorter longitudinal wall portion of said enlarged end portion next adjacent said opening, said tongue extending traversely of the longitudinal axis fo said enlarged end portion of said duct means. 22. Apparatus as defined in claim 1, comprising further valve means connected serially in said duct means, said further valve means comprising a housing defining a float chamber and a float disposed in said float chamber the portion of said duct means extending between said float chamber and said container being of larger cross-sectional area then that of the duct portion extending between said float chamber and said first mentioned valve means. Other info: Inventors: Rinck, Hans-Joachim (7900 Ulm (Danube), DT) Application Number: 500404 Filing Date: 1974-08-26 Publication_date: 1976-02-03 Assignee: Primary Class(es): 116/227 73/303 Other Classes: US Patent Ref:
Other Refs:
Primary Examiner: Swisher, S. Clement Assistant Examiner: Corr, Denis E. Attorney: |
|