Carton filling system

Abstract: A system for dispensing liquid food products is disclosed. The product is drawn from a source (6) to a metering chamber (20) through a supply valve (10), and then conducted to a dispensing valve (24) to fill preformed containers. The valves have a valve stem (45) that reciprocates to open and close the valve. The valve stem is supported in the passage through which the product flows by bearings. The bearings have balls (52) that engage the stem (45) and the wall of the passage (46). The use of balls to support the stem facilitates cleaning of the passage after use, and yet provides good support for the valve stem.

Description: This invention relates to an apparatus for filling preformed cartons with liquid contents, and more particularly to an apparatus for controlling the flow of liquid for filling cartons and for cleaning the apparatus following use. Various systems have been proposed and used for filling cartons with liquids, such as milk and juice. Typically, the cartons are preformed and sealed at the bottom. The cartons are placed on a conveyor which advances periodically in a series of equal steps. The cartons first pass through a sterilization station where the interior of the cartons is sterilized. The cartons then pass to a fill station where the liquid contents are transferred from a supply tank to fill the carton. The carton then passes to a closing station where the top of the carton is folded together, and finally the carton passes to a sealing station where the thermoplastic-coated carton is heat-sealed at the top. The liquid fill system of conventional machines provides for dispensing a measured quantity of liquid in each carton by means of various valve arrangements. Periodically, the pipes and valves must be cleaned and sterilized. Typically, this involves conducting a sterilization fluid through the fill system where it comes in contact with the valves and seals to remove any residual milk or juice and to kill any bacteria that might be present in the system. While prior fill systems have been capable of filling cartons, there is a need for improving the efficiency of the filling system and for improving the arrangement for cleaning the filling system. The present invention relates to an apparatus for dispensing liquid products into individual containers in measured quantities from a source of the liquid product, including a dispensing valve for controlling flow of the liquid product into the containers, the dispensing valve having a valve seat and a valve element cooperating with the valve seat and having a valve stem supported in a valve body to displace the valve element toward and away from engagement with the valve seat by axial movement of the valve stem, and including a bearing arrangement for supporting the valve stem (see e.g. US-A-5 025 991). According to the invention the bearing comprises a plurality of balls engaging the valve stem to provide axial alignment of the valve stem while allowing reciprocating movement of the valve stem with sufficient space between the balls to permit the flow of liquid product and cleaning solutions around the valve stem. In a preferred form of the invention, the product, which may be milk or juice, is supplied to a metering chamber through a supply valve which opens and closes by means of a pneumatic cylinder. From the supply valve, the liquid flows to the metering chamber where the quantity of liquid for filling a carton is temporarily stored. A dispensing valve is mounted below the metering chamber. The dispensing valve opens and closes in response to an electro-pneumatic actuator. The components of the fill system are arranged to provide adequate slope for drainage during the cleaning operation. The valve stems for the supply valve and the dispensing valve have linear ball bearings which avoid obstruction of the liquid through the valve passages and provide minimal obstruction to the cleaning fluid during the cleaning operation. A preferred embodiment of the invention is illustrated in the accompanying drawings, in which: Fig. 1 is an elevational view, partially schematic, of a filling arrangement in accordance with this invention; Fig. 2 is a cross-sectional view of the dispensing valve actuator; Fig. 3 is a cross-sectional view of the supply valve; Fig. 4 is a cross-sectional view of the supply valve along the line 4-4 in Fig. 3; and Fig. 5 is a cross-sectional view of the metering pump. In a conventional filling machine, preformed cartons 2 are closed at the bottom and positioned on a conveyor 4 which advances intermittently toward the right as viewed in Fig. 1. The carton 2 has an open top through which liquid contents are supplied to fill the carton. Subsequently, the carton 2 will be closed at the top and heat-sealed. The fill apparatus in accordance with this invention includes a product tank 6 which contains the liquid that is to be filled into trip carton 2. The product tank 6 has a suitable control system for maintaining a predetermined level of liquid in the tank. A pipe 8 connects the tank 6 with a supply valve assembly 10 which includes a control valve 12 and a pneumatic cylinder 14. The control valve 12 supplies liquid to a dispensing pump 16 which includes an electrical actuator 18 and a pump chamber body 20. A pipe section 22 connects the control valve 12 with the chamber body 20. The chamber body 20 is also connected with a dispensing valve assembly 24 which includes a dispensing valve 26 and an electro-pneumatic actuator 28. The actuator 28 includes a solenoid 30 which controls a poppet valve 32. Air is supplied to opposite sides of a floating piston 34 through air supply hoses 36 and 38. An air passage 40 connects the lower side of the piston 34 with the poppet valve 32. When the poppet valve 32 is open, air from the lower side of the piston 34 bleeds through the passage 40 and through the valve 32, thereby reducing the pressure on the lower side of the piston so that the pressure on the upper side of the piston drives the piston downwardly as viewed in Fig. 2. A valve stem 42 is attached at its upper end to the piston 34 so that downward movement of the piston 34 causes the valve stem 42 to move downwardly. A coil spring 44 urges the piston 34 upwardly as viewed in Fig. 2 in the event of loss of air pressure. The valve stem 42 extends into the valve element 26 in order to operate the dispensing valve at the lower end of the valve stem. The supply valve 12 is shown in Fig. 3 in cross-section. The valve 12 has a valve stem 45, which extends through a central bore 46 in the body of the valve 12. A valve element 48 is provided at the lower end of the valve stem 44 and a valve seat 50 is provided in the bore 46 to form a seal with the valve element 48. The valve stem 45 is caused to reciprocate in the valve body 12 by the pneumatic actuator 14. The valve stem is guided in the bore 46 by a pair of ball guides formed by three ball bearings 52, each of which is received in a longitudinal groove 54 formed in the valve stem 44. For illustration purposes, the ball bearing that cooperates with one of the grooves 54 in Fig. 3 has been omitted. For both bearings, it is necessary to have at least three balls to center the valve stem 45. The grooves 54 are elongated to allow longitudinal movement of the valve stem while the balls 54 rotate relatives to the surface of the bore 46 during up and down motion of the valve stem 44. The same bearing arrangement is provided for the discharge valve 26, as shown in Fig. 1. The valve element for dispensing the liquid into the cartons may be of any suitable type. For example, the valve elements described in U.S. Patent No. 5,025,991, No. 4,903,740, or No. 4,869,397 may be used. Liquid product is supplied to the dispensing valve 26 through a connector 56 from the dispensing pump 16. The chamber body 20 has a piston chamber 58 with a port 60 through which liquid product is discharged from the chamber 58 into the central bore of the dispensing valve 26, as shown in Fig. 2. The metering pump assembly is shown in cross-section in Fig. 5 and includes an actuator 18 and a chamber body 20. The chamber body 20 has a central bore which forms a cylindrical metering chamber 58. A reciprocating piston 62 is mounted in the chamber 58. Force for displacing the piston 62 is transmitted to the piston 62 by a shaft 64. Force is applied to displace the shaft 64 towards the right for drawing liquid product into the chamber 58 and towards the left for displacing liquid product out of the chamber by means of an electrically-driven rotary gear 66. The gear 66 has spiral grooves which operate with a reciprocating carriage which is prevented from rotating by the guide 70 which is fixed to the end plate of the actuator 18. The carriage 68 slides longitudinally along the guide 70, and since the shaft 64 is fixed to the carriage 68, longitudinal movement of the carriage causes corresponding movement of the shaft 64. The carriage is provided with a plurality of spiral rollers which transmit axial forces to the carriage in response to rotation of the gear 66. Rotation is imparted to the gear by motor coils 72 of a reversible motor. Suitable controls are provided for adjusting the rate of rotation of the gear 66 by the motor and for controlling the direction of rotation of the gear 66. A sensor 74 is positioned adjacent the shaft 64 to provide a signal corresponding to the position of the piston 62 in the chamber 58. For example, the position sensing means may include grooves or relief formed in the shaft 64 that could be sensed by the sensor 74, or other appropriate marking means could be provided. The sensor 74 cooperates with the control means for adjusting the displacement of the piston 62 to correspond to various sizes of cartons that are to be filled. As shown in Fig. 1, the electro-pneumatic positioning mechanism 28 and the pneumatic cylinder 14 are connected to a control system 76 which controls the timing of the opening of the supply valve 12 and the dispensing valve 26. The control system 76 also controls the actuation of the pump actuator 18 for drawing liquid product into the chamber 58 and discharging the product from the chamber 58 into the dispensing valve 26. The control system 76 contains a timing system for controlling the duration and sequencing of the actuators 14, 28 and 18 to correspond to the size of the carton 2 and the rate of advance of the conveyor 4. In operation, the tank 6 receives a supply of liquid product for filling cartons. The control system 76 causes the actuator 14 to displace the valve stem 45 downwardly to open the valve and, at the same time, the actuator 18 displaces the shaft 64 toward the right as viewed in Fig. 5 to draw liquid product into the chamber 58. During this period, the dispensing valve 26 is closed. When the piston 62 has been displaced sufficiently to draw in the predetermined quantity of liquid product into the chamber 58, the supply valve 12 is closed by the actuator 14 and the dispensing valve 26 is opened at the same time that the actuator 18 displaces the piston 62 toward the left as viewed in Fig. 5 to cause the liquid product to flow out of the dispensing valve 26 and into the carton. The rate of flow through the dispensing valve is controlled by the rate of displacement of the piston 62, which in turn is controlled by the rate of rotation of the gear 66 in response to excitation of the motor coils 72. In this manner, the operation of the fill system can be adjusted electrically to provide optimum filling conditions of the system. During cleaning of the system, cleaning solution is deposited in the tank 6 and the system is operated in the same manner as during product filling operation. The use of ball bearing guides for the valves 12 and 26 permits efficient cleaning of the valve guides, since the bearing components are fully exposed to the cleaning solution. While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

Claims: Apparatus for dispensing liquid products into individual containers (2) in measured quantities from a source (6) of the liquid product, including a dispensing valve (26) for controlling flow of the liquid product into the containers, the dispensing valve having a valve seat and a valve element cooperating with the valve seat and having a valve stem (42) supported in a valve body to displace the valve element toward and away from engagement with the valve seat by axial movement of the valve stem, and including a bearing arrangement for supporting the valve stem, characterized in that the bearing comprises a plurality of balls (52) engaging the valve stem to provide axial alignment of the valve stem while allowing reciprocating movement of the valve stem with sufficient space between the balls to permit the flow of liquid product and cleaning solutions around the valve stem. The apparatus according to claim 1 wherein the balls (52) have a diameter greater than the distance between the valve stem (42) and the wall of the valve body, and including a plurality of recesses (54) in the valve stem for receiving and retaining the balls. The apparatus according to claim 2 wherein there are a first set of balls and a second set of balls, each of the sets of balls (52) including at least three balls, and the first and second sets being spaced longitudinally of the valve stem. The apparatus according to any of claims 1 to 3 wherein the valve body has an interior cylindrical wall, and the balls (52) roll on the surface of the interior wall. The apparatus according to any preceding claim including a metering chamber device (16) for displacing a predetermined quantity of liquid product through the dispensing valve (26) into the containers (2). The apparatus according to claim 5 including a supply valve (12) for controlling flow of liquid product from the source (6) of the liquid product to the metering chamber (20), the supply valve having a valve seat (50) and a valve element (48) cooperating with the valve seat and having a valve stem (45) supported in a valve body to displace the valve element toward and away from engagement with the valve seat by axial movement of the valve stem, and including a bearing arrangement for supporting the valve stem in which a plurality of balls (52) engage the valve stem to provide axial alignment of the valve stem while allowing reciprocating movement of the valve stem with sufficient space between the balls to permit the flow of liquid product and cleaning solutions around the valve stem of the supply valve. The apparatus according to claim 6 wherein the valve stem (45) includes a plurality of recesses (54) for retaining the balls (52). The apparatus according to claim 5 including a supply valve (12) for controlling flow of liquid product from the source (6) of the liquid product to the metering chamber (20), and wherein the metering chamber device (16) includes a movable piston (62) for adjusting the volume of the metering chamber to correspond to the size of the container (2) that is to be filled. The apparatus according to any of claims 5 to 8 including a control system (76) for controlling the operation of the dispensing valve (26) and the metering chamber device (16) and the supply valve (12).

Inventors: PERREAULT SUSAN G, RODRIGUE JOHN, PERREAULT, SUSAN G., RODRIGUE, JOHN
Applicants: TETRA LAVAL HOLDINGS & FINANCE, TETRA LAVAL HOLDINGS & FINANCE S.A.
Application year: 1993
Main classification: B65B39
IPC codes: B65B3, B65D5, B65B55, B65B39, B67D7