FIXED DISPLACEMENT PUMP

TECHNICAL FIELD [0101] The present application relates generally to beverage dispenser components and more particularly relates to a fixed displacement solenoid pump for use within a beverage dispenser or in other types of fluid transport devices and systems.

BACKGROUND OF THE INVENTION [0102] Variable displacement solenoid pumps are widely used in beverage dispensers and in the beverage industry in general. These pumps generally have a hydraulic flow rate depending on the fluid to be pumped, the working pressure, and the electromagnetic temperature. The working pressure may vary according to the resistance opposed to the pumping system. These pumps are in wide use in the industry because they generally have small dimensions, low price, and low operating costs.

[0103] The beverage industry, however, is moving towards the use of ever smaller individual beverage components. For example, a beverage may include a number of micro-ingredients, a number of macro-ingredients, and a number of diluents. The micro-ingredients may have a reconstitution ratio of about ten (10) to one (1) or more, and in many cases, even one hundred (100) to one (1) or more. See, e.g., commonly owned U.S. Patent Publication No. 2007/0205221 entitled "Beverage Dispensing System" and U.S. Patent Publication No. 2007/0205220 entitled "Juice Dispensing System."

[0104] As a result of the use of these ever smaller components, there is a desire to meter accurately these small amounts of fluids in a consistent and repeatable fashion. Likewise, these fluids preferably should be metered in a relatively inexpensive pump that may be easy to install, use, and repair.

SUMMARY OF THE INVENTION [0105] The present application thus provides a fixed displacement pump. The fixed displacement pump may include a chamber, a piston positioned within the

chamber, and a collar positioned within the chamber to as to limit movement of the piston within the chamber.

[0106] The fixed displacement pump further may include an electric coil surrounding the chamber and a piston spring attached to the piston. The collar may be positioned outside of the piston spring or inside of the piston spring. The collar may integral with the chamber or nonintegral with the chamber. The collar may include a predetermined length. The fixed displacement pump further may include a number of collars with varying lengths.

[0107] The application further describes a method of retrofitting a variable displacement pump having a chamber and a piston therein. The method may include positioning a collar within the chamber, limiting the extent of a stroke of the piston within the chamber by the collar, and operating the pump as a fixed displacement pump.

[0108] The method further may include determining a desired length of the stroke of the piston. The step of positioning the collar may include positioning a collar of a predetermined length.

BRIEF DESCRIPTION OF THE DRAWINGS

[0109] Fig. 1 is a side cross-sectional view of a known variable displacement solenoid pump. [0110] Fig. 2 is a side cross-sectional view of a fixed displacement solenoid pump as is described herein.

[0111] Fig, 3 is a side cross-sectional view of an alternative embodiment of a fixed displacement solenoid pump as is described herein.

DETAILED DESCRIPTION

[0112] Referring now to the drawings in which like numerals refer to like elements among the several views, Fig. 1 shows a known variable displacement solenoid pump 10. As is described above, several variable displacement solenoid pumps are known in the beverage dispenser industry and elsewhere. These known pumps include pumps sold by ULKA S.r.L. of Pavia, Italy, the Lee Company of Westbrook, Connecticut, Valcor Engineering Corp., of Springfield, New Jersey, Bio-Chem Valve of

Boonton, New Jersey, and others. Fig. 1 shows a variable displacement solenoid pump offered by LiLKA S.r.L. under the designation ^* 'NME Evolution Micropump."

[0113] Generally described, the variable displacement pump 10 may include an upper connection 15. The upper connection 15 may be in communication with an ingredient line, a diluent line, or any other fluid source. Positioned within or about the upper connection 15 may be an upper spring 20 and an upper valve 25. The upper valve

25 may control the flow rate into the pump 10.

[0114] The upper valve 25 may be in communication with a piston valve 30 positioned about a piston chamber 35. A piston 40 may be positioned within the piston chamber 35. The piston 40 may be made of a magnetizeable material. The piston 40 may be in contact with one or more piston springs 45. The piston chamber 35 may be surrounded by a magnetic structure 50. The magnetic structure 50 may include an electronic coil 55. Activation of the electronic coil 55 causes the piston 40 to move within the piston chamber 35 via magnetic attraction or repulsion with the magnetic structure 50.

[0115] The piston chamber 35 in turn leads to a lower connection 60. The lower connection 60 may be in communication with the components of the beverage dispenser or otherwise.

[0116] As is well known, activation of the magnetic structure 50 and the electronic coil 55 causes the piston 40 to maneuver along the piston chamber 35. Once the magnetic structure 50 and the electronic coil 55 are turned off, the piston springs 45 return to the piston 40 in the opposite direction. As such, the interaction of the piston 40, the magnetic structure 50, the electronic coil 55, and the springs 45 may create a pumping action so as to pump fluid from a fluid source to a desired destination. Similar types of solenoid pumps 10 and/or other pumps are known in the art and may be used herein.

[0117] Fig. 2 shows a fixed displacement solenoid pump 100 as is described herein. The fixed displacement solenoid pump 100 may be largely identical or similar to the variable displacement solenoid pump 10 described above, but with the addition of an outside collar 110 positioned within the piston chamber 35. The outside collar 1 10 may be a separate element that is positioned outside of the piston springs 45 or the outside collar 110 may be an extension of the piston chamber 35 itself. The outside collar 1 10

limits the travel of the piston 40 within the piston chamber 35. Other configurations may be used herein. The outside collar 1 10 may have a predetermined length so define the extent of travel of the piston 40 within the piston chamber 35. Although the term "collar" is used, any structure that iimits the travel of the piston 40 is within the intended scope of the term. The outside collar 110 generally may be made of a non-magnetizeable material.

[0118] As a result of the use of the collar 1 10. the displacement of the pump 100 as a whole is constant. Specifically, the output of the pump 100 is a function of the displacement within the piston chamber 35 as limited by the outside collar 1 10 and the number of strokes of the piston 40. The outside collar 1 10 thus turns the variable displacement solenoid pump 10 into the fixed displacement solenoid pump 100. As such, the fixed displacement solenoid pump 100 may operate as an open loop metering pump.

[0119] Fig. 3 shows an alternative embodiment of a fixed displacement solenoid pump 120, In this embodiment, the fixed displacement solenoid pump 120 includes an inside collar 130. The inside collar 130 may be positioned inside the piston springs 45. The inside collar 130 may be a separate element or the inside collar 130 may be an extension of the lower connection 60 or otherwise molded into the piston chamber 35 or other elements of the pump 120. Other configurations may be used herein. Again, the inside collar 130 limits the travel of the piston 40 such that the output of the fixed displacement solenoid pump 120 is a function of the displacement of the piston 40 and the number of piston strokes.

[0120J The fixed displacement solenoid pumps 100, 120 thus accurately and consistently pump small volumes of fluid as needed. The pumps 100, 120 can be easily retrofit with the collars 1 10, 130 or the collars 1 10, 130 may be original equipment. The length of the collars 1 10, 130 may vary according to the desired displacement per stroke of the piston 40. A number of collars 110, 130 with varying lengths may be used. The use of the collars 1 10, 130 may be applicable to pumps other than the examples provided above.