Portion control dispensers
A dispenser for dispensing portions of flowable materials has a piston that is advanced along a dispensing chamber by rotation of a spindle that passes through the piston. A stop may limit travel of the piston to control the volume of flowable material dispensed. The stop may be adjustable. In an example hand-held dispenser the spindle is rotated by a rack and pinion mechanism that can be operated with one hand. The dispenser may be used, for example, for dispensing portions of condiments, sauces or the like.
1. A dispenser for dispensing flowable materials, the dispenser comprising:
a reservoir in fluid communication with a dispensing chamber;
a one-way valve in a path connecting the reservoir and the dispensing chamber, the one way valve oriented to permit flow of a flowable material from the reservoir into the dispensing chamber;
a piston movably fitted in the dispensing chamber;
at least one outlet port in the dispensing chamber; and
a mechanism for advancing the piston along the dispensing chamber, the mechanism comprising:
a spindle extending through an opening in the piston, the spindle having helical features engaged with features on the piston; and
a handle operable to rotate the spindle;
wherein the spindle is rotatable to advance the piston along the dispensing chamber in response to movement of the operating handle.
2. A dispenser according to claim 1 comprising a pinion rotatable with the spindle wherein the handle is coupled to the spindle by a linkage comprising a rack engaging the pinion.
3. A dispenser according to claim 1 wherein the handle is coupled to the spindle by a linkage configured to convert reciprocating motion of the handle to rotary motion of the spindle.
4. A dispenser according to claim 1 wherein the one-way valve is carried on the piston.
5. A dispenser according to claim 4 wherein the one-way valve comprises an annular valve member movable between a closed position wherein one or more apertures in the piston are substantially blocked by the valve member and an open position wherein the one or more apertures provide fluid communication between the reservoir and the dispensing chamber.
6. A dispenser according to claim 1 comprising a body defining the dispensing chamber wherein the reservoir is removably coupled to the body.
7. A dispenser according to claim 6 wherein the reservoir comprises a tubular vessel having openings at first and second ends thereof; a removable cap closing the opening at the first end and the second end removably coupled to the body.
8. A dispenser according to claim 7 comprising a one-way air inlet valve in the removable cap.
9. A dispenser according to claim 1 comprising a blade mounted for rotation with the spindle, the blade blocking the outlet port when the piston is in a retracted position and uncovering the outlet port upon rotation of the spindle to advance the piston.
10. A dispenser according to claim 1 comprising a plurality of outlet ports in the dispensing chamber and a plurality of blades mounted for rotation with the spindle, each of the blades blocking a corresponding one of the outlet ports when the piston is in a retracted position and uncovering the corresponding outlet port upon rotation of the spindle to advance the piston.
11. A dispenser according to claim 1 comprising a pressure-operated one way valve in the outlet port.
12. A dispenser according to claim 1 comprising a body defining the dispensing chamber wherein the operating handle is pivotally coupled to the body.
13. A dispenser according to claim 1 comprising a stop configurable to set a desired limit on travel of the piston.
14. A dispenser according to claim 13 wherein the stop comprises a ring and the spindle extends through the ring.
15. A dispenser according to claim 1 comprising a body defining the dispensing chamber and one or more feet extending downwardly from the body wherein the outlet port is in fluid communication with a dispensing nozzle recessed relative to the one or more feet.
16. A dispenser according to claim 1 wherein the outlet port is in fluid communication with a dispensing nozzle and the dispensing nozzle comprises diverging opening.
17. A dispenser according to claim 16 wherein the diverging opening comprises a hemispherical recess.
18. A dispenser according to claim 1 wherein the piston comprises a peripheral edge including one or more longitudinal grooves and the longitudinal grooves receive longitudinal ridges projecting from a wall of the dispensing chamber.
19. A dispenser according to claim 18 wherein the longitudinal ridges are inclined relative to an axis of rotation of the spindle.
20. A dispenser according to claim 1 comprising a bias mechanism connected to apply a torque to the spindle in a direction that tends to retract the piston.