Liquid dispensing device

Abstract

A burette consisting of a calibrated syringe chamber with a top flange and a reciprocable dispensing plunger. The plunger has a top actuator with a depending vertical rod on which is adjustably mounted a stop collar serving as a dispensing volume indicator and being engageable with said top flange to limit the upward extension of the plunger. The syringe chamber has a bottom outlet conduit including a check valve which opens when the plunger is drawn upwardly. The syringe chamber also has a discharge conduit at the level of the lowermost position of the bottom end of the plunger, the discharge conduit having a check valve which opens when the plunger is pushed downwardly for a discharge stroke. The chamber has a vent tube connected thereto at its lower portion. Below this the chamber has a peripheral rib, and O-rings are mounted on the chamber above and below the rib. An internally threaded annular cap surrounds the O-rings and acts to clamp the O-rings against the intervening rib when the cap is tightened on the neck of a container, so as to provide an air-tight seal relative to the container when the cap is tightened.

What is claimed is: .[.1. A burette device comprising a vertical cylindrical syringe chamber provided at its top end with an outwardly projecting stop flange, a dispensing plunger slidably and sealingly mounted in said chamber and having an enlarged horizontal top actuating portion, a depending vertical rod secured to said actuating portion and extending parallel to said chamber, a stop collar adjustably secured on said rod and being engageable with said stop flange to limit upward extension of said plunger, a horizontal outlet conduit formed integrally with said chamber substantially at the level of the bottom of said plunger in its lowermost position, a vertical upstanding check valve chamber integrally formed on the outer end of said outlet conduit and being provided with an outwardly and downwardly inclined discharge tip, said check valve chamber being provided with an upwardly facing ball seat, a movable valve ball on said seat, the inner wall of the check valve chamber being integrally formed with an inwardly projecting stop lug overlying said ball and limiting upward movement thereof, means on the lower end of said syringe chamber to sealingly support the syringe chamber in the mouth of a liquid container, a check valve housing formed integrally with the lower end of said syringe chamber, a depending vertical intake tube formed integrally with and communicating with the bottom of said housing and defining a ball seat at its top end, a movable valve ball on said last-named seat, and an inwardly projecting stop lug integrally formed on the inside wall of said housing, overlying said last-named valve ball and limiting upward movement thereof..]. .[. 2. The structure of claim 1, and wherein said check valve housing is substantially spherical in shape and is connected to the syringe chamber by a substantially frusto-conical upwardly flaring wall element..]. .[.3. The structure of claim 2, and an outwardly projecting vent tube integrally formed with and communicating with the lower end of the syringe chamber subjacent said wall element and above said sealing means..]. .[.4. The structure of claim 2, and wherein said sealing means comprises an enlarged hollow frusto-conical downwardly tapering stopper member..]. .[.5. The structure of claim 2, and wherein said sealing means comprises an outwardly projecting annular sealing rib integrally formed on the lower portion of the syringe chamber, annular resilient deformable sealing rings surrounding the syringe chamber above and below said rib, and an annular internally threaded cap member surrounding said sealing rings and having a top wall provided with a central aperture just large enough to pass said sealing rib..]. .[.6. The structure of claim 4, and an outwardly projecting vent tube on the top wall of said stopper member..]. .[.7. The structure of claim 1, and a scale on the vertical syringe chamber..]. .Iadd. 8. A burette device comprising a vertical cylindrical syringe chamber provided at its top end with an outwardly projecting stop flange, a vertically extending volumetric scale on said vertical syringe chamber having volume indications reading from smaller amounts to larger amounts in a downward direction, a dispensing plunger slidably and sealingly mounted in said chamber and having an enlarged horizontal top actuating portion, a depending vertical rod secured to said actuating portion and extending parallel to said chamber, a stop collar adjustably secured on said rod and being engageable with said stop flange to limit upward extension of said plunger, said stop collar serving as a mechanical stop for measuring the volume to be dispensed and, when the plunger is in its lowermost position, for accurately indicating on said scale the volume to be dispensed, a horizontal outlet conduit formed integrally with said chamber substantially at the level of the bottom of said plunger in its lowermost position, said plunger being normally in said lowermost position, a vertical upstanding check valve chamber integrally formed on the outer end of said outlet conduit and being provided with an outwardly and downwardly inclined discharge tip, said check valve chamber being provided with an upwardly facing ball valve seat, a movable valve ball on said seat, the inner wall of the check valve chamber being integrally formed with an inwardly projecting stop lug overlying said ball and limiting upward movement thereof, means on the lower end of said syringe chamber to sealingly support the syringe chamber in the mouth of a liquid container, a check valve housing formed integrally with the lower end of said syringe chamber, a depending vertical intake tube formed integrally with and communicating with the bottom of said housing and defining a ball seat at its top end, a movable valve ball on said last-named seat, and an inwardly projecting stop lug integrally formed on the inside wall of said housing overlying said last-named valve ball and limiting upward movement thereof, wherein said sealing means comprises an outwardly projecting annular sealing rib integrally formed on the lower portion of the syringe chamber, respective annular resilient deformable sealing rings surrounding the syringe chamber above and below said rib, and an annular internally threaded cap member surrounding said sealing rings and having a top wall provided with a central aperture just large enough to pass said sealing rib. .Iaddend. .Iadd. 9. A burette device comprising a vertical cylindrical syringe chamber provided at its top end with an outwardly projecting stop flange, a vertically extending volumetric scale on said vertical syringe chamber having volume indications reading from smaller amounts to larger amounts in a downward direction, a dispensing plunger slidably and sealingly mounted in said chamber and having an enlarged horizontal top actuating portion, a depending vertical rod secured to said actuating portion and extending parallel to said chamber, a stop collar adjustably secured on said rod and being engageable with said stop flange to limit upward extension of said plunger, said stop collar serving as a mechanical stop for measuring the volume to be dispensed and, when the plunger is in its lowermost position, for accurately indicating on said scale the volume to be dispensed, a horizontal outlet conduit formed integrally with said chamber substantially at the level of the bottom of said plunger in its lowermost position, said plunger being normally in said lowermost position, a vertical upstanding check valve chamber integrally formed on the outer end of said outlet conduit and being provided with an outwardly and downwardly inclined discharge tip, said check valve chamber being provided with an upwardly facing ball valve seat, a movable valve ball on said seat, the inner wall of the check valve chamber being integrally formed with an inwardly projecting stop lug overlying said ball and limiting upward movement thereof, means on the lower end of said syringe chamber to sealingly support the syringe chamber in the mouth of a liquid container, a check valve housing formed integrally with the lower end of said syringe chamber, a depending vertical intake tube formed integrally with and communicating with the bottom of said housing and defining a ball seat at its top end, a movable valve ball on said last-named seat, and an inwardly projecting stop lug integrally formed on the inside wall of said housing overlying said last-named valve ball and limiting upward movement thereof, wherein said stop collar is provided with a downwardly divergent frusto-conical annular bottom flange extending adjacent said volumetric scale. .Iaddend.