US20060151058A1

US20060151058A1 - Product dispensing apparatus

Info

Publication number: US20060151058A1
Application number: US10/870,033
Authority: US
Inventors: John Salaoras; Hugn Farguson
Original assignee: INDUSTRIAL PROCESS INNOVATIONS Inc
Current assignee: INDUSTRIAL PROCESS INNOVATIONS Inc
Priority date: 2004-06-18
Filing date: 2004-06-18
Publication date: 2006-07-13

Abstract

A product dispensing apparatus for filling a container with product material has an enclosure for holding a supply of product material, a discharge outlet in the enclosure, and a gate device mounted adjacent the discharge outlet for controlling the flow of material through the outlet. The gate device is provided with a plate slidable across the discharge outlet between a fully closed position wherein the plate completely covers the discharge outlet and a maximum open position wherein the plate is generally clear of the discharge outlet and one or more partially open positions located between the maximum open and fully closed positions. The gate device is further provided with an actuator having a driven member connected to the plate for moving the plate among the closed, maximum open, and partially open positions, and stopping means adjacent the actuator for stopping the plate at the partially open positions.

Description

FIELD OF THE INVENTION

This invention relates to product dispensing equipment for dispensing product material into containers.

BACKGROUND OF THE INVENTION

Product dispensing systems can be used for dispensing a product, such as sugar or flour, into containers for sale or transport. It is advantageous that these dispensing systems fill the containers quickly so that production time (and associated costs) are kept to a minimum. It is also desirable that these dispensing systems fill the containers with an accurate amount of product so that a consumer is getting at least the amount of product stated on the container without overfilling the container. Any overfill would of course amount to giving product away without receiving any payment for such product.
Canadian Patent Application 2,276,757 (Salaoras) discloses a product delivery system having a sliding gate. The sliding gate is movable between a plurality of positions corresponding to different outlet openings through which the product is dispensed. By controlling the size of the outlet opening, the product can be dispensed at a rapid rate in the initial filling process, and at progressively slower rates when approaching the target product delivery amount.
The sliding gate in the '757 patent is controlled by a plurality of pneumatic cylinders. As a result of the multiple air cylinders, a relatively complicated network of piping is required to connect each air cylinder to a pressurized air supply. Furthermore, using a plurality of cylinders to provide multiple plate positions for the sliding gate requires elaborate mountings for interconnecting the cylinders. Accordingly, the delivery device is rather complex and costly to manufacture, is susceptible to a higher incidence of failure, and is relatively difficult to service.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve on the prior art. It is another object of the invention to provide a product dispensing device having a sliding gate for controlling the flow of product from the device. It is another object to provide a dispensing apparatus having a gate device and configured to move the gate device among open, closed, and pre-selected intermediate positions quickly and accurately. It is another object to provide a dispensing apparatus having a gate device with easily adjustable pre-selected intermediate positions. It is another object of the present invention to provide a dispensing apparatus with a gate device that operates reliably and is easy to maintain. These and other objects are provided by features described in the claims. The following summary provides an introduction to the invention which may reside in a combination or sub-combination of features provided in this summary or in other parts of this document.
According to one aspect of the present invention, a product dispensing apparatus for filling a container with product material is provided. The apparatus has an enclosure for holding a supply of product material, a discharge outlet in the enclosure, and a gate device mounted adjacent the discharge outlet for controlling the flow of material through the outlet.
The gate device is provided with a plate slidable across the discharge outlet between a fully closed position wherein the plate completely covers the discharge outlet and a maximum open position wherein the plate is generally clear of the discharge outlet and one or more partially open positions located between the maximum open and fully closed positions.
The gate device is further provided with an actuator having a driven member connected to the plate for moving the plate among the closed, maximum open, and partially open positions, and stopping means adjacent the actuator for stopping the plate at the partially open positions.
The stopping means can include a brake having a locking element for releasably engaging at least one of the driven member of the actuator and the plate.
The dispensing apparatus can include a control system in communication with the brake, and brake control means for activating and deactivating the brake. The brake can be controlled pneumatically, using air pressure is to control the activation and deactivation of the brake.
The control system can include sensors adjacent at least one of the plate and the actuator, the sensors adapted to detect the position of the plate corresponding to each the partially open positions and to send a corresponding signal to the control system.
The dispensing apparatus can have a fill sensor for detecting the amount of product material dispensed into the container. The fill sensor can be a transducer in electrical communication with the control system.
The dispensing apparatus can include a container holding device from which an upper end of the container is suspended, and a suspension framework to which the container holding device is secured. The container holding device can be movable in a vertical plane relative to the suspension framework. The transducer can be mounted between a portion of the container holding device and the suspension framework so that a force is applied across the transducer in proportion to the weight of the container.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example to the accompanying drawings that show embodiments of the present invention, and in which:
FIG. 1 is a front view of a dispensing apparatus according to the present invention;
FIG. 2 is a portion of the apparatus of FIG. 1 showing a gate device and adjacent elements in greater detail;
FIGS. 3 a-3 e show the gate device of FIG. 2 with a plate in different positions;
FIG. 4 is a top view of the gate device of FIG. 2;
FIG. 5 is a section view of the gate device of FIG. 4 taken along the lines 5-5;
FIG. 6 is a section view of the gate device of FIG. 4 taken along the lines 6-6;
FIG. 7 is a perspective view of a slide frame of the gate device of FIG. 2;
FIG. 8 is a cross-sectional view of a stopping device of the apparatus of FIG. 1;
FIG. 9 is a cut-away view of a control system of the apparatus of FIG. 1;
FIG. 10 is an enlarged view of a portion of the apparatus of FIG. 1 showing a container holder device in greater detail;
FIG. 11 is a side view showing details of an alternate configuration for mounting and sensing the weight of a container to be filled by the apparatus of FIG. 1; and
FIG. 12 is a rear view of a portion of the apparatus of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

A product dispensing apparatus according to the present invention is shown generally at 100 in FIG. 1. The product dispensing apparatus 100 has an enclosure 102 for holding product material 104 to be dispensed, a discharge outlet 106 in the enclosure 102, and a gate device 108 mounted adjacent the discharge outlet 106 for controlling the flow of the product material 104 from the enclosure 102 through the outlet 106.
In the illustrated embodiment, the enclosure 102 is in the form of a hopper 110 having sidewalls 112. The hopper 110 has an upper inlet opening 114 for receiving a supply of the product material 104, and a lower end 116 from which the discharge outlet 106 extends.
The hopper 110 is supported above a floor by a support structure 118 so that a container 119 into which the product material is to be dispensed can be positioned below the discharge outlet 106 of the hopper 110. More particularly, in the embodiment illustrated, a container holding device 120 is provided below the outlet 106 and supported in place by the support structure 118. The container 119, which in the illustrated embodiment is in the form of a bag, can be suspended from the container holding device 120. Further details of the container holding device 120 are provided hereinafter.
Referring now to FIG. 2, the gate device 108 of the apparatus 100 is mounted below the discharge outlet 106, and above the container 119. The gate device 108 has a plate 126 that is slidable across the discharge outlet 106. In the illustrated embodiment, the plate is linearly slidable along a slide axis 127. The plate 126 can slide among a plurality of plate positions 128 to vary the amount by which the plate 126 obstructs the discharge outlet 106. Increasing or decreasing the amount by which the plate 126 obstructs the outlet 106 causes a corresponding decrease or increase in the effective size of the opening through which product material 104 can escape the hopper 110.
Referring now to FIGS. 3 a-3 e, the plurality of plate positions 128 of the plate 126 includes a fully closed position 128 a (FIG. 3 a) in which the plate 126 completely obstructs the discharge outlet 106, a maximum open position 128 b (FIG. 3 b) in which the plate 126 is generally clear of the discharge outlet 106, and one or more partially open positions 128 c in which the plate 126 is between the fully closed 128 a and maximum open 128 b positions. In the embodiment illustrated, the plate 126 has three partially open positions 128 c, namely 128 c-1 (FIG. 3 c), 128 c-2 (FIG. 3 d), and 128 c-3 (FIG. 3 e), corresponding to approximately 60% open, 30% open, and 5% open conditions of the outlet 106 (relative to cross-sectional area of the maximum open position 128 b). The three partially open positions 128 c are set using gate position sensors 129, as will be further described hereinafter.
Referring again to FIG. 2, to slidably support the plate 126 adjacent the outlet 106, the illustrated embodiment of the gate device 108 is provided with a gate housing 130. As best seen in FIGS. 4-6, the gate housing 130 has two parallel, spaced apart retaining panels 132 each having an aperture 134 at one end and support legs 136 extending away from the aperture 134.
A slide frame 140 (see also FIG. 7) is sandwiched between the two panels 132 such that the frame 140 is in alignment with the apertures 134. More particularly, the slide frame 140 has opposing longitudinal side members 142 oriented parallel to the slide axis 127, and opposing front and rear transverse members 144, 146 extending between the side members 142. The members 142, 144, 146 of the frame 140 present interior surfaces 148 that are aligned with the perimeter of the apertures 134 in the retaining panels 132. Accordingly, the frame 140 and the apertures 134 cooperate to form a generally continuous channel 135 through the gate housing 130.
Longitudinal grooves 150 are provided along the interior surfaces 148 of the longitudinal side members 142 of the slide frame 140. The grooves 150 are sized to receive the side edges of the plate 126 in sliding fit. The rear transverse member 146 has a slot 152 through which the plate 126 can slide. The slot 152 extends transversely between the longitudinal grooves 150 of the opposing side members 142, and the height of slot 152 is sized to be slightly greater than thickness of the plate 126. The front transverse member 144 can have a transverse groove 154 along its interior surface 148, to receive the front edge of the plate 126. Engagement of the front (or leading) edge of the plate 126 in the transverse groove 154 can improve the obstructing action of the outlet 106 by the plate 126 when the plate 126 is in the fully closed position 128 a.
The gate housing 130 is secured to the lower end 116 of the hopper 110 such that the discharge outlet 106 of the hopper and the channel 135 of the housing 130 are substantially aligned. Shrouding or funneling panels (not shown) can be installed between the outlet 106 and the gate housing 130 to ensure that any product material 104 leaving the outlet 106 is directed into the channel 135 of the housing 130. By sliding the plate 126 within the slide frame 140, any desired degree of obstruction of the channel 135, and hence of the outlet 106, can be provided.
The housing 130 (and hence the plate 126) can be oriented at an incline from the horizontal to inhibit jamming of the plate 126 when the plate 126 moves in a direction from the maximum open position 128 b towards the fully closed position 128 a (FIG. 2). In the embodiment illustrated, the plate 126 is inclined so that leading edge is at a lower elevation than the trailing edge. The amount of incline is about 20-30 degrees from the horizontal.
Referring still to FIGS. 4-6, the gate device 108 of the apparatus 100 is further provided with an actuator 160 having a driven member 162 connected to the plate 126, for moving the plate 126 among the various plate positions 128. The actuator 160 can be in the form of, for example, but not limited to, a pneumatic cylinder (rod or rodless types), a hydraulic cylinder, or a motor driven actuator.
In the embodiment illustrated, the actuator 160 comprises a pneumatic cylinder 161 having an extensible/retractable cylinder rod 163 as the driven member 162. A coupling bracket 164 can be provided between the plate 126 and the rod 163, for connecting the plate 126 and the rod 163 together. The cylinder 161 has a stationary housing portion 165 that can be secured to the gate housing 130. A mounting bar 138 can be provided between the ends of the legs 136 for supporting the housing portion 165 of the cylinder 161.
Advance and return air lines 166 and 168 extend from rear and front ends 170, 172 of the cylinder 161, respectively. Supplying pressurized air to the advance air line 166 moves the plate 126 towards the fully closed position 128 a, and supplying pressurized air to the return air line 168 moves the plate 126 towards the maximum open position 128 b.
To stop the plate 126 at any one of the various plate positions 128, the gate device 108 is provided with stopping means 176 for releasably engaging at least one of the driven member 162 of the actuator 160 and the plate 126. In the embodiment illustrated, the stopping means 176 is mounted adjacent the front end 172 of the actuator 160 and releasably engages the driven member 162 of the actuator 160.
Referring now to FIG. 8, in the illustrated embodiment the stopping means 176 comprises a pneumatic brake 177 mounted adjacent the cylinder 161. The brake 177 has an axial bore 178 through which the rod 163 of the cylinder 161 passes, and a locking element 180 movable between engaged and released positions 182, 184, respectively. When in the engaged position 182, the locking element 180 engages the cylinder rod 163 so that axial movement of the rod 163 is inhibited. When in the released position 184, the locking element 180 is clear of the cylinder rod 163 so that the rod 163 can slide smoothly through the bore 178.
In the illustrated embodiment, the locking element 180 comprises a pair of brake shoes 181 a, 181 b disposed on opposite sides of the rod 163. The locking element 180 is mechanically biased towards the engaged position 182 by a compression spring 185. The locking element 180 can be moved to the released position 184 by providing pressurized air to a brake air line 186. An auxiliary locking air line can be provided to the brake 177 to work with the spring 185 in urging the locking element 180 to the engaged position 182.
The present invention comprehends the use of stopping means 166 other than a pneumatic brake 177. For example, if a hydraulic actuator is used, back pressure can be used in the actuator to stop the motion of the driven member. If a motor controlled actuator is used, the stopping means 176 can be in the form of a mechanical brake, or alternatively, electrical current can be used to provide a stopping and/or holding torque on the motor.
Referring now to FIG. 9, to control the movement of the plate 126 by the actuator 160, the apparatus 100 may be provided with a control system 190. The control system 190 can include a controller 192, which can be, for example, but not limited to, a Programmable Logic Controller (PLC).
The control system 190 in the illustrated embodiment is provided with actuator control means 194 and brake control means 196 in communication with a PLC 192. The cylinder control means 194 includes an advance and a return valve 200, 202, respectively, fitted in line with the advance and return air lines 166, 168, respectively. The valves 200 and 202 are provided with solenoids 204 for moving the valves between open and closed positions. Similarly, the brake control means 196 comprises a brake valve 208 fitted in line with the brake air line 186. The brake valve 208 is also equipped with a solenoid 204 for actuation of the valve. The solenoids 204 are in electrical communication with the PLC 192, so that the PLC 192 can send electrical signals to the solenoids 204 and so advance and return the cylinder rod 163, and move the brake between the engaged and released positions 182, 184.
The control system 190 also includes position sensors 210 adjacent at least one of the plate 126 or the actuator 160 for detecting the axial position of the plate 126. More specifically, position sensors 210 can be placed adjacent the path of travel of the plate 126 and/or the driven member 162 of the actuator 160, at locations along the path of travel corresponding to the various plate positions 128. The position sensors can be in the form of, for example, but not limited to, proximity sensors or limit switches. Digital encoders can also be used to provide position gearing feedback signals to the OLC 192.
In the illustrated embodiment, the sensors 210 are in are in the form of magnetic reed switches, and the rod 163 of the actuator 160 is provided with a magnet 212 that trips the switches 210 when passing. The sensors 210 c-1, 210 c-2, and 210 c-3 are fastened to the housing 165 of the cylinder 161 at positions corresponding to the position of the magnet 212 when the plate 126 is in the partially open positions 128 c-1, 128 c-2, and 128 c-3, respectively.
To move the plate 126 between, for example, the partially open positions 128 c-1 and 128 c-2, the PLC 192 energizes the solenoid 204 on the brake valve 208 to release the brake. Then solenoid 204 on the advance valve 200 is energized, so that the rod 163 of the cylinder 161 advances. When the magnet 212 passes and trips the position sensor 210 c-2, the PLC immediately de-energizes the solenoid 204 on the brake valve 208 so that the brake moves to the engaged position 182. As well, the advance valve 200 can be shuttled so that air supply to air line 166 is shut off. The rod 163, and hence the plate 126, is thereby stopped at the partially open position 128 c-2.
It is to be appreciated that the location of the position sensors 210 c along the travel path of the rod 161 and or plate 126 effectively establish the axial location of plate corresponding to each of the partially open positions 128 c. These locations can be adjusted to optimize the dispensing cycle for various product materials 104 that may be dispensed.
Using the sensors 210 at the partially open positions 128 c of the plate 126 has been explicitly referred to above. A person skilled in the art will appreciate that positions sensors 210 may not be required for detecting the fully closed 128 a or maximum open 128 b positions of the plate 126 because it is usually possible to set up the cylinder 161 such that the rod 163 has a maximum stroke length equal to the distance between the two extreme plate positions 128 a and 128 b. In other words, at those positions, the position of the rod 163 (and hence the plate 126) can be defined by allowing the cylinder 161 to bottom out or to contact a fixed abutment (positive stop). Nevertheless, it may be advantageous to provide sensors 210 a and 210 b at the fully closed 128 a and maximum open 128 b positions for a number of reasons. These reasons can include, for example, a reduction in wear and tear on the cylinder 161, and to provide additional flexibility in controlling the dispense cycle by adjusting these positions 128 a and 128 b (particularly the maximum open position 128 b).
The control system 190 of the apparatus 100 may further be provided with a fill sensor 218 for detecting the amount of product material 104 dispensed into the container 119. The fill sensor 218 can be in the form of, for example, but not limited to, a weight sensor such as a load cell, or a volume sensor such as distance or photoelectric sensors. In the illustrated embodiment, the fill sensor 218 comprises a transducer (or load cell) 219 for measuring the weight of the container 119 containing product material 104.
As best seen in FIG. 10, the transducer 219 is mounted such that the weight of the container 119 (and its contents) is proportional to a compressive force 220 applied across the transducer 219. This can generally be accomplished by providing a suspension framework 221 from which the container holding device 120 (with an attached container 119) is suspended. The container holding device 120 is movably secured to the suspension framework at least in a vertical plane, and the transducer 219 can be positioned between the movable holding device 120 and the suspension framework 121. At least a portion of the weight of the container holding device 120 (and attached container 119) can bear against the transducer 219.
As best seen in FIG. 10, in one embodiment, the suspension framework 221 comprises a pair of vertical legs 222 extending from the frame 118 on opposed sides of the discharge outlet 106. A generally horizontal shelf portion 224 extends inwardly from one leg 222. A horizontal hanger arm 238 extends inwardly from the opposed leg 222.
The container holding device 120 has upper and lower horizontal members 226 and 228, respectively, and uprights 230 extending between the horizontal members 226, 228, and on opposite sides of the discharge outlet 106. In the illustrated embodiment, the container holding device 120 is further provided with a bag clamp assembly 232 secured to the lower horizontal member 228, such that the container 119 can be suspended from the holding device 120.
The container holding device 120 is pivotably secured to the suspension framework 221 by means of a pivot bolt 234 passing horizontally through one of the uprights 230 and the hanger arm 238. The upper horizontal member 226 of the holding device 120 has an extension arm 240 that is positioned vertically above the shelf portion 224 of the mounting bracket 222. The transducer 219 is mounted between the shelf portion 224 and the arm 240. Since the holding device 120 can pivot about the pivot bolt 234, an increase in weight of the container 119 holding product material 104 is reflected in an increased compressive force 220 exerted by the arm 240 on the transducer 219. Accordingly, as the container 119 is filled with product material 104, the downward force 220 exerted by the arm 240 on the transducer 219 increases. The transducer 219 sends an electrical signal to the PLC 192 which varies in accordance with the magnitude of the downward force 220.
The mounting location of the transducer 219 according to this embodiment is above the container 119, which reduces the possibility of the transducer 219 becoming contaminated or damaged by spillage of the product material 104. Furthermore, the motion of the arm 240 when exerting the force 220 on the transducer 219 is limited to a single axis, namely, a rotational axis about the pivot bolt 234. This can reduce the amount of vibration or other undesirable forces transmitted to the load cell, so that more accurate weight measurement is possible.
Referring now to FIGS. 11 and 12, an alternative transducer mounting configuration includes a suspension framework 321 and a container holding device 320. The suspension framework 321 has a generally horizontal shelf portion 324 extending between vertical webs 325. The vertical webs 325 are secured to extend downward from the gate housing 130 adjacent the discharge outlet 106. The transducer 219 is mounted on the shelf portion 324, between the webs 325.
The container holding device 320 has a bracket arm 330 and a bag clamp assembly 332. The bracket arm 330 has an upper horizontal hanger bar 334 with vertical plates 336 extending downward and outward from the hanger bar 334. The hanger bar 334 extends generally parallel to the shelf 324, and is secured at the central portion to an upper surface of the transducer. The vertical plates 336 extend outward to a position generally underneath the discharge outlet 106. The bag clamp assembly 332 is suspended from the vertical plates 336. This configuration provides an essentially cantilevered mounting arrangement of the container holding device 320 relative to the suspension framework 321, which in turn allows movement of the container holding device in a generally vertical plane, relative to the suspension framework 321. Accordingly, the weight of the bag 119 secured to the bag clamp assembly 332 is reflected in the magnitude of the force 220 exerted on the transducer 219, which is sandwiched between the shelf 324 and hanger bar 334.
In the embodiment illustrated, to secure the bag clamp assembly 332 to the plates 336, the plates 336 are provided with generally parallel horizontal slots 338 that are open to a forward edge 340 of the plates 336. The bag clamp assembly 332 has a structural hoop 342 for lining the throat of the bag 119, and a pair of pins 344 extending generally horizontally and outwardly from either side of the hoop 342. The pins 344 are sized to be slidingly received in the slots 338 of the plates 336. The pins 344 can be in the form of bolts with thumb tabs to facilitate installation and removal of the bag clamp assembly 332 from the arm 330.
The mounting bracket 322 and the container holding device 320 provide a transducer mounting configuration wherein the transducer is mounted above the container 119, rather than below the container 119. As well, the cantilevered arrangement of the arm 330 relative to the transducer 219 provides freedom of movement of the results in the force 220 exerted on the transducer 219 to follow a generally single-axis vector, namely, a moment that results from the action and reaction forces acting at spaced apart locations along the body of the transducer 219. This can improve the accuracy of the signal generated by the transducer 219 by isolating or filtering “noise” generated by vibration and other mechanical effects.
In use, the PLC 192 can continuously monitor the transducer 219 during a fill cycle, to keep track of how full the container 119 is getting. As the weight of the container 119 increases, the plate 126 of the gate device 108 can be moved to successively less open (or more obstructed) positions 128.
Use of the transducer 219 to trigger changes in the position 128 of the plate 126 can be accomplished by, for example, but not limited to, establishing discrete pre-selected weight set-points, which are less than the target weight of a “filled” container 119. When the PLC 192 acknowledges that a particular set-point has been reached, the position of the plate 126 can be adjusted by the PLC as described previously.
In a particular method for dispensing product material 104 using the apparatus 100 of the present invention, three pre-selected weight set-points are established. The first set-point is set at a weight corresponding to about 50% of the target (filled) weight. The second and third set-points are set at about 75% and 90% of the target weight, respectively. The method provides a two-stage dispensing cycle, namely, a bulk dispensing stage and a dribble dispensing stage. The bulk dispensing stage fills the container 119 to about 90-95% of the target weight in a minimum amount of time. The dribble dispensing stage fills the container 119 to 100% of the target weight.
Before initiating the bulk dispensing cycle, certain start conditions must be satisfied. These start conditions include securing an empty container 119 to the container holding device 120. As well, the plate 126 should be in the fully closed position 128 a. The transducer 119 can be tared and calibrated, if required.
The bulk dispensing cycle can then be initiated, either manually or automatically (using sensors to confirm that the start conditions have been satisfied). The plate 126 is moved from the fully closed position 128 a to the maximum open position 128 b, by controlling the brake 177 and cylinder 161, as described previously. Moving the plate 126 away from the fully closed position 128 a allows product material 104 to flow from the hopper 110 into the container 119, which accordingly increases the force 220 on the transducer 219.
When the transducer 219 signals that the container 119 has reached the first set-point, the plate 126 is moved to the first partially open position 128 c-1. This increases the obstruction of the discharge outlet 106 by the plate 126, so that the product material 104 continues to be dispensed into the container 119, but at a reduced rate.
When the second weight-set point is reached, the PLC 192 moves the plate 126 to the second partially open position 128 c-2 to further reduce the fill rate. These reductions in the fill rate reduce the chance of overfilling the container 119 while yet maintaining a relatively fast fill rate.
When the third set-point is reached, the container 119 is almost filled to final target and the bulk dispensing cycle ends. The plate 126 is moved to the fully closed position 128 a.
Before starting the dribble dispensing cycle, the controller pauses for a stabilization delay to ensure a stable, accurate weight measurement is being read by the transducer 219. Lower than actual weight readings can result from material 104 having passed through the outlet 106 and the plate 126, but not yet having settled in the container 119. Higher than actual weight readings (or spikes) can result from the force of the impact of the dispensing material 104 landing upon the dispensed material 104 already in the container 119. The stabilization delay allows the product material 104 to settle in the container 119 so that the chance of registering inaccurate weight readings is minimized.
After the stabilization delay, the container 119 will still be slightly less than full. The dribble dispensing stage then begins by shuttling the plate 126 from the fully closed position 128 a to the third partially open position 128 c-3, and then immediately back to the fully closed position 128 a. This dispenses a single shot (or batch) of product material 104 into the container 119. The PLC 192 again pauses for the stabilization delay and then compares the weight sensed by the transducer 219 to the target weight. If the measured weight of the container 119 is below the target weight, the dribble routine is repeated. If the target weight has been reached or exceeded, the dispensing cycle is complete.
This method has been found to produce very favourable performance in filling containers 119. The method has been found to be much faster than existing filling methods, and fills the containers 119 to a more accurate level. In addition, the apparatus 100 has fewer moving parts than previous dispensing apparatus, and is easier and less costly to maintain. As well, the apparatus is highly flexible in that the dispensing cycles can conveniently be adjusted to optimize the cycle time and accuracy in response to the type of product material 104 being dispensed and/or the type of container 119 being filled. For example, the quantity and magnitude of the weight set-points can adjusted by simply altering the PLC program. As well, the quantity and axial position of the sensors 210 along the travel path of the cylinder 160 and/or plate 126 can be easily altered.
While preferred embodiments of the invention have been described herein in detail, it is to be understood that this description is by way of example only, and is not intended to be limiting. The full scope of the invention is to be determined from reference to the appended claims.

Claims

1. A product delivery apparatus for filling a container with product material, the apparatus comprising:

a) an enclosure for holding a supply of product material;

b) a discharge outlet in the enclosure; and

c) a gate device mounted adjacent the discharge outlet for controlling the flow of material through the outlet, the gate device comprising:

i) a plate slidable across the discharge outlet between a fully closed position wherein the plate completely covers the discharge outlet and a maximum open position wherein the plate is generally clear of the discharge outlet and one or more partially open positions located between the maximum open and fully closed positions;

ii) an actuator having a driven member connected to the plate for moving the plate among the closed, maximum open, and partially open positions; and

iii) stopping means adjacent the actuator for stopping the plate at least at the partially open positions.

2. The apparatus of claim 1 wherein the stopping means comprises a brake having a locking element for releasably engaging at least one of the driven member of the actuator and the plate.

3. The apparatus of claim 2 further comprising a control system in communication with the brake and having brake control means for activating and deactivating the brake.

4. The apparatus of claim 3 wherein air pressure is used to control the activation and deactivation of the brake.

5. The apparatus of claim 3 wherein the control system further comprises sensors adjacent at least one of the plate and the actuator, the sensors adapted to detect the position of the plate corresponding to each the partially open positions and to send a corresponding signal to the control system.

6. The apparatus of claim 3 further comprising a fill sensor for detecting the amount of product material dispensed into the container.

7. The apparatus of claim 6 wherein the fill sensor comprises a transducer in electrical communication with the control system.

8. The apparatus of claim 7 further comprising a container holding device from which an upper end of the container is suspended, and a suspension framework to which the container holding device is secured.

9. The apparatus of claim 8 wherein the container holding device is movable in a vertical plane relative to the suspension framework.

10. The apparatus of claim 9 wherein the transducer is mounted between a portion of the container holding device and the suspension framework so that a force is applied across the transducer in proportion to the weight of the container.