WO1994020220A1

WO1994020220A1 - Apparatus for conveying and electrostatically charging powder

Info

Publication number: WO1994020220A1
Application number: PCT/US1994/002587
Authority: WO
Inventors: Michael Don Bray
Original assignee: Maddox Metal Works, Inc.
Priority date: 1993-03-11
Filing date: 1994-03-11
Publication date: 1994-09-15
Also published as: CN1099954A; AU6401794A

Abstract

The invention is an applicator for electrostatically charging and dispensing particulate materials. The applicator has an arm (18) for conveying the material from a supply bin (14) to an electrostatic charging element (50) that is mounted within the arm for rotation. An electrostatic charge is applied to the charging element by a control system. Particulate material is contacted by the rotating charging element, electrostatically charged, and dispensed by the charging element through an opening (54) in the arm.

Description

APPARATUS FOR CONVEYING AND ELECTROSTATICALLY CHARGING POWDER.

TECHNICALFIELD

This invention relates to the application of particulate material to the exterior of articles and, in particular, the electrostatic application of seasoning and other ingredients to food products.

BACKGROUND AND SUMMARY OF THE INVENTION

Many staple food products available to consumers today have been either

completely or partially processed, increasing greatly the convenience to the consumer. Only a few examples of such products include breads, rolls, crackers and snack foods, which are either fully cooked and ready to eat or require cooking or heating before serving. The overwhelming majority of such products are commercially processed in large quantities, to increase quality control while reducing the price to consumers of such products.

The process of preparing these food products generally includes a number of separate processes conducted sequentially. These generally include preparation of ingredients forming the food product, mixture of the ingredients, proofing of the mixture (if yeast or other leavening ingredients are used), possibly cooking the product, and seasoning the exterior of the product as desired. Though each process step may be conducted separately, the overall quality and cost of the finished product can be substantially improved simply by improving the effectiveness or reducing the cost of any process step.

A process step that is perhaps the most difficult to control and most costly is the application of seasoning to the exterior of food products. This step is generally completed either after the food product has been formed and proofed, or later, after the product has been cooked. For example, flour or other seasoning might be applied to dough products, such as bread, after a proofing process has allowed the dough to rise. Other products, such as potato chips, tortilla chips, crackers and other snack foods, are generally seasoned with salt and other seasonings after cooking. Because seasonings added to food products are often both the most costly ingredients and have the most impact on flavor and product quality, increasing the efficiency, effectiveness and consistency of seasoning application is highly desirable.

A number of shortcomings associated with existing methods and apparatus for applying seasoning to food products are caused by difficulties in securing the seasoning to the product surface and in controlling the quantity of seasoning required to cover the product acceptably. These difficulties often result in substantial amounts of seasoning being wasted, undue maintenance of equipment and work areas required to recover unwanted and uncontrolled deposits either misdirected or carried through the air, related interruptions in the seasoning process that slow preparation of the food product, and increased cost resulting from these shortcomings. For example, in many applications, the seasoning application process must be frequently interrupted to dean the equipment and work area. Of course, the seasoning recovered cannot practically be returned to the process, but is instead thrown away.

In an effort to reduce these difficulties, at least two approaches have been taken, neither of which has been satisfactory. One approach is to wet the surface of the food products with oil, either by application or, in the case of chips and other snack foods, by cooking the products so that they retain more oil. in this way, the seasoning applied to the product tends to stick to the wet surface, rather than bouncing off the product. Unfortunately, this approach typically causes the product to contain a higher content of oil or fat than is desirable and further increases the overall product cost. Another approach is to electrostatically charge the seasoning before being deposited on the food product. The food product or the surface on which it rests is given a charge that is either neutral or opposite that of the charged seasoning, thus causing attraction of the seasoning to the surface of the product. However, available processes and devices incorporating this approach have not been sufficiently efficient, effective or consistent in their ability to adhere the seasoning to the product and to control the direction and quantity of seasoning applied to the food product.

The present invention overcomes these and other shortcomings associated with existing processes and devices for seasoning food products. While the present invention has application to seasoning of food products, it will be apparent that the invention may find other applications beyond the preparation of food products. The invention includes a method and apparatus in which an applicator controls and directs particulate material, such as seasoning, to an electrostatically charged element. The electrostatically charged element contacts the particulate material, imparting an electrostatic charge to at least a substantial portion of the material, and drives the material from the applicator. The charged material exiting the applicator is deposited onto food products at a controlled rate with a substantially consistent electrostatic charge. The food products and their supporting surface are charged either neutrally or opposite to that of the deposited material, causing both attraction and adherence of the material to the food product. BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be had by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings wherein:

FIGURE 1 is a partially cut away perspective view of a preferred embodiment of the invention;

FIGURE 2 is an exploded perspective view, illustrating construction and assembly of the applicator arm of the preferred embodiment of the invention;

FIGURE 3 is an end view of the applicator arm shown in FIGURE 2, in an assembled configuration; FIGURE 4 is a side view of the applicator arm shown in FIGURE 2, in partial section and in an assembled configuration;

FIGURE 5 is a perspective view of a preferred embodiment of a charging element for incorporation in the preferred embodiment of the invention;

FIGURE 6 is an end view of the charging element of FIGURE 5 in partial section, for incorporation in the preferred embodiment of the invention;

FIGURE 7 is a section view taken along line 7-7 of FIGURE 1 , illustrating a support bracket utilized with the applicator arm of the preferred embodiment of the invention;

FIGURE 8 is a section view taken along line 8-8 of FIGURE 1 , illustrating a support bracket of the applicator arm of the preferred embodiment of the invention;

FIGURES 9A and 9B schematically illustrate the control system of the preferred embodiment of the invention; and FIGURE 10 is a schematic view of the control panel of the preferred embodiment of the invention shown in FIGURE 1.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a perspective view in partial section, illustrating an electrostatic applicator 10 incorporating the present invention, for dispensing particulate material. The electrostatic applicator 10 includes a base 12, on which is mounted a bin 14 for containing seasonings or other particulate matter processed by the electrostatic applicator 10. Mounted on one end of the bin 14 is a drive assembly 16. Mounted on the other end of the bin 14 is an applicator arm 18. Mounted on the exterior of the bin 14 is a control system 20, for directing the overall operation of the electrostatic applicator 10. A speed controller 22 is also mounted on bin 1 , for controlling the speed of the drive assembly 16. The applicator arm 18 is shown inserted into a schematic representation of a tumbler drum 23 (shown in phantom lines) containing food products, such as tortilla chips, for example. Seasoning is charged and delivered within the tumbler drum 23, where the seasoning and food products are tumbled together. This allows the charged seasoning to contact and adhere to the surface of the food products with an electrostatic bond.

Mounted within the bin 14 for rotation are a delivery auger 24 and a relatively larger mixing auger 26. Both of the delivery auger 24 and mixing auger 26 are rotated by the drive assembly 16. The mixing auger 26 surrounds the delivery auger 24. The delivery auger 24 extends through an opening in the bin 14 and into the applicator arm 18. When rotated, the mixing auger 26 stirs the seasonings or other material within the bin 14, to assist in providing a steady supply of material to the delivery auger 24 and to mix the contents (if necessary) of the bin 14. The delivery auger 24 transports seasoning or other material from the bin 14, through the applicator arm 18. The windings of delivery auger 24 and mixing auger 26 preferably have windings in opposite directions, to promote stirring of the contents of the bin 14 during operation.

The drive assembly 16 rotates the delivery auger 24 and mixing auger 26 by means of a 3-phase electric motor 28 connected to the augers through an associated speed reducing assembly (not shown). The assembly of base 12, bin 14, drive assembly 16, drive assembly speed controller 22, and mixing auger 26 are available from Acrison, inc., 20 Empire Boulevard, Moonachie, New Jersey, and are identified by Model No. 105Z. The bin 14 is preferably manufactured from stainless steel to prevent corrosion and enhance durability.

FIGURE 2 is an exploded perceptive view illustrating the assembly of components comprising the applicator arm 18. The applicator arm 18 Is mounted on the bin 14 by means of a mounting plate 34, which is securely bolted to the bin 14. Centrally located through the mounting plate 34 is an opening 30 through which extends the delivery auger 24. Secured to the mounting plate 34 by means of welding is a first transport section 38, manufactured from a stainless steel conduit, to resist corrosion, enhance durability and facilitate its welding to the mounting plate 34. The flanges 36 are also secured between the mounting plate 34 and first transport section 38 by means of welding, to reinforce support to the cantiievered mount of the first transport section 38. Mounted to and extending from the first transport section 38 is a second transport section 40, manufactured from Nylon* conduit, to provide an electrically insulating conduit, resist corrosion, enhance durability and reduce frictional resistance to rotation of the delivery auger 24 within. The first and second transport sections 38 and 40 have ferrules 42 and 44 extending from their adjacent ends. The first and second transport sections 38 and 40 are secured together by a triclamp 46 tightened over the adjacent ferrules

42 and 44, to create a seal relatively impervious to the escape of seasonings or other materials conveyed within the applicator arm 18.

Extending from within the bin 14 and through the first and second transport sections 38 and 40 is the delivery auger 24. The delivery auger 24 is manufactured from Nylon-⁹, to provide an electrically insulating means for transporting particulate material, resist corrosion, enhance durability and reduce frictional resistance to rotation within the transport sections 38 and 40. The delivery auger 24 includes an integral, continuous helical winding, machined from a larger Nylon* rod. The windings of the delivery auger 24 form a right-hand flight for conveying seasonings or other materials from the bin 14 and through the first and second transport sections 38 and 40 of the applicator arm 18. Machined into a shank 48 of the delivery auger 24 are internal threads 49 (FIGURE 4), which are secured to a drive shaft (not shown) of the drive assembly 16 extending into the bin 14.

Secured to the end of the delivery auger 24 adjacent the free end of the applicator arm 18 is a charging element 50 manufactured from 303 stainless steel, for its electrical conductivity, resistance to corrosion, and durability. The charging element 50 is secured for rotation by the delivery auger 24 within the second transport section 40 of the applicator arm 18. The delivery auger 24 and transport section 40 electrically insulate the charging element 50 from the remainder of the applicator arm 18. Extending radially from the charging element 50 are a number of paddles 52, for contacting and imparting an electrostatic charge to seasonings or other materials transported to the charging element 50 by the delivery auger 24. Each of the paddles 52 extends along a portion of the length of the charging element 50 and is positioned to rotate past a discharge slot 54 milled through the second transport section 40, adjacent the free end of the section. Referring briefly to FIGURE 4, the shank 53 of the charging element 50 is secured by a spring pin 55 within an aperture 59 in the delivery auger 24 for concomitant rotation.

The discharge slot is positioned horizontally from the center line of the second transport section 40. This positioning of the discharge slot 54 causes the paddles 52 of the charging element 50 to engage and lift seasoning or other material received from the delivery auger 24, prior to discharge from the applicator arm 18 through the discharge slot 54. Dispensation of particulate material through the discharge slot 54 is represented by two unnumbered arrows.

An end piece 56 is secured to the free end of the second transport section 40. The end piece 56 is for supporting the free end 57 of charging element 50 for rotation, for maintaining electrical contact between the control system 20 and the charging element 50, and for allowing the escape of seasoning or other materials driven beyond the discharge slot 54 of the second transport section 40. An electrostatic charge is delivered to the end piece 56 from the control system 20 via an insulated charge line 58. The line 58 is strung through the support brackets 60 and 62 secured about the first and second transport sections 38 and 40. Also strung through the support brackets 60 and 62 is an air delivery line 64, manufactured from PVC or other suitable material. The air delivery line delivers low pressure air to an air direction assembly 66 (FIGURES 2, 3 and 4) mounted adjacent to end piece 56. The air direction assembly 66 channels air from the delivery line 64 for directing and dispersing seasoning or other materials from the discharge slot 54.

Referring now to FIGURES 2, 3, and 4, there is illustrated in detail the construction and assembly of the components of the applicator arm 18 and the air direction system 66. The end piece 56 includes a body 68 manufactured from ultra high molecular weight (UHMW) plastic. The body 68 includes an extension

70, having a receptacle 72 for receiving and holding the charge lead 58 in a friction grip. The body 68 of the end piece 56 is secured about the end of the transport section 40 with a friction fit created by tightening a counter-sunk bolt 73 within a threaded aperture 75, to tighten the body 68 about the transport section 40 in a manner similar to the triclamp 46. A threaded aperture 74 is drilled and tapped through the opposing face of the extension 70, to receive a metallic, electrically-conductive screw 76, manufactured from stainless steel. The charge lead 58 includes outer and inner electrically insulating sheaths

78 and 80, respectively. Extending within the inner sheath 80 Is an electrically- conductive graphite core 82. The terminus of the charge lead 58 is tiered and cross-sectioned such that the inner sheath 80 extends from the outer sheath 78, and the graphite core 82 extends, in turn, beyond the inner sheath 80. The receptacle 72 is configured to matingly receive the tiered cross-section of the terminus of the charge lead 58. Stabbed into the terminus of the core 82 is a chrome-plated steel tack 84. When inserted into the receptacle 72 of the extension 70, the charge lead 58 urges the tack 84 of the core 82 into engagement with the threaded screw 76 to create electrical continuity between the charge lead 58 and threaded screw 76.

The body 68 of the end piece 56 includes an aperture 86, for rotationally supporting the free end 57 of the charging element 50 and allowing electrical communication between the charge lead 58 and the charging element 50. The aperture 86 has a tiered cross-section for matingly receiving an annular bushing

88, for supporting the free end 57 of the charging element 50, and an annular seal 90, for preventing the passage of seasoning or other materials into the bushing 88. The bushing 88 is manufactured of a durable plastic and engages the aperture 86 with a friction fit. The seal 90 is manufactured of palm plastic, relatively hard and durable, and is also secured within the aperture 86 with a friction fit.

Electrical communication between the charge lead 58 and charging element 50 is accomplished via a brush assembly 92. The brush assembly 92 includes a graphite brush 94, to which is secured a steel lead 96. Surrounding the lead 96 and secured to the brush 94 is a steel spring 98. An electrically insulating phenolic plastic sleeve 100 surrounds and is secured to a brass, electrically-conductive barrel 102. An aperture of square cross-section runs through the center of the barrel 102 and is sized to receive the square cross- section of the brush 94. Sufficient clearance is provided between the surfaces of the brush 94 and aperture of the barrel 102 to allow the brush 94 to slide freely.

A threaded screw cap 104, having a plastic electrically-insulating outer surface, engages and closes the upper opening of the barrel 102. The upper end of the spring 98 extends through the aperture of the barrel 102 and is restrained by the screw cap 104. The brush assembly 92 is secured to the end piece body 68 by a friction fit between ribs 105 extending from the sleeve 100 against the inner surface of an aperture 106. The aperture 106 is formed through the body 68 and opens into the aperture 86, such that the center lines of apertures 106 an 86 substantially intersect. A bearing ring 108 manufactured of 660 bearing bronze is secured to the shank 53 of the charging element 50 by a friction fit, for engagement and electrical contact with the brush 94 of the brush assembly 92. When the end piece 56 is assembled, the shank 53 of the charging element 50 is secured within the aperture 86 and the brush assembly 92 is secured within the aperture 106. The brush 94 is kept in continuous contact with the bearing ring 108 and the charging element 50, by the spring 98. The wire lead 96 of the brush assembly 92 is secured to the screw 76, to establish electrical continuity with the charge lead 58 and control system 20.

A release slot 110 provides an outlet from the aperture 86 to the exterior of the end piece body 68. The release slot 110 allows seasoning or other materials driven beyond the discharge slot 54 and into the end piece 56, to escape, rather than becoming compacted and interfering with rotation and operation of the charging element 50. The release slot 110 extends beyond 180 degrees around the circumference of the cylindrical portion of end piece body 68. The air direction assembly 66 at the end of the applicator arm 18 utilizes air from the air delivery line 64 to aid in dispersion and direction of material dispensed through the discharge slot 54 and to reduce or eliminate the accumulation of particulate material and dust on the exposed surfaces of the steel lead 96 and free end 57 of the charging element 50. The assembly 66 diverts air to the discharge slot 54 through a pair of flexible and adjustable tubes 111, each of which extend from a Y joint 127 and terminate in a directing nozzle 113. Flow of air through the tubes 111 is adjustable between nil to full flow rates by a valve 115, mounted to a T fitting 125 for pivotal adjustment about an axis normal to the longitudinal axis of the air delivery line 64. The directing nozzles 113 are each fan-shaped, and positioned above and adjacent the discharge slot 54, to widen and direct a stream of air downwardly past the discharge slot 54. Material dispensed from the discharge slot 54 encounters the air streams and tends to be broken into smaller constituent groups, thus reducing or eliminating clumps from the flow of material and aiding in dispersion of the material. Particulate material is also entrained by the widening air streams and directed downwardly in a widening pattern which both further disperses the material and reduces or eliminates floatation of the material away from the desired target (food or other underlying products) to other undesirable locations, such as other equipment, the floor and to personnel.

A second pair of adjustable tubes 117 are connected to the air delivery line 64 and extend over the opposite side of the applicator arm 18. The flow of air through the tubes 117 is adjustable from nil to full flow rates by a second valve 119, which is mounted on the T fitting 125 for pivotal movement about an axis normal to the longitudinal axis of the air delivery line 64. Each of the tubes 117 extends from a Y joint 129 and terminates in a nozzle 121 similar in construction and operation to the nozzles 113. The nozzles 113 are positioned to direct air flow over the exposed surfaces of the steel lead 96, the free end 57 of the charging element 50 and their associated components. This reduces or eliminates the undesirable collection of seasoning, dust or other particles attracted by the electrostatic charge of such components.

The air distribution assembly 66 is composed of plastic, electrically non- conductive fittings available under the LOC-UNE^® brand, from Lockwood Products, Inc., 5615 SW Willow Lane, Lake Oswego, Oregon. Adjustment of each of the tubes 111 and 117 may easily be made to adjust the flow of air from the nozzles 113 and 121 to the location and direction desired. The flow rate is also easily adjusted by the valves 115 and 119. The air direction assembly 66 thus allows variation of the location, direction and flow rate of air throughout a virtually unlimited range of combinations.

FIGURE 4 illustrates in detail the construction of the first and second transport sections 38 and 40 of the applicator arm 18. The first and second transport sections 38 and 40 include tapered ferrules 42 and 44, respectively. Each of the ferrules 42 and 44 is tapered at an angle of approximately 20 degrees, such that the tightening of the triclamp 46 about the ferrules 42 and 44 draws the first and second transport sections 38 and 40 into tight engagement. Milled into the outwardly facing surface of the ferrule 42 is an annular groove 112 positioned concentrically with the first transport section 38. Extending from the outwardly facing surface of the ferrule 44 and aligned concentrically with the second transport section 40 is a rib 114 for engaging the groove 112 of the first transport section ferrule 42. Engagement of the groove 112 and rib 114 aligns the first and second transport sections 38 and 40 as the triclamp 46 is tightened and provides a seal against the escape of seasoning transported by the delivery auger 24. The second transport section 40 is easily removed for cleaning or for replacement with a section of different length, by releasing the triclamps 46. The position of the discharge slot 54 may also be easily varied by loosening the triclamp 46 and rotating the second transport section 40 as desired.

FIGURES 5 and 6 are a perspective view and partial section end view, respectively, of a charging element 200. The charging element 200 is a preferred embodiment substitute for the charging element 50. Features of the charging element 200 that are identical in construction and operation to corresponding features of the charging element 50 are identified with the same reference numeral, followed by a prime (" ' ") designation. The shank 53' of the charging element 200 can be secured within the applicator arm 18, to the transport auger 24, with a pin such as spring pin 55 (FIGURE 4) for concomitant rotation. A number of paddles 202 extend helically about the rotational axis of the charging element 200. Each helical paddle 202 forms a right-hand flight which presents a surface that moves particulate material received from the transport auger 24 toward the end piece 56 when the charging element 200 is rotated. When utilizing the charging element 200, the second transport piece 40 is first adjusted to position the discharge slot 54 directly below the rotational axis of the charging element 200. The charging element 200 is electrically conductive and manufactured from 303 stainless steel. A desired electrostatic charge is applied to the charging element 200 by the control system

20 and brush assembly 92.

The paddles 202 extend along a portion of the charging element 200 substantially equivalent in length and adjacent to the discharge slot 54. As the charging element 200 is rotated, particulate material moved by the paddles 202 passes over and falls through the underlying discharge slot 54. Movement of the particulate material by the paddies 202 toward the end piece 56 distributes the material over the discharge slot 54, thereby enhancing uniform flow and dispersion of the material from the entire length of the discharge slot 54. As each paddle 202 contacts the particulate material, an electrostatic charge is imparted to the material. Contact with the particulate material is increased by the helical configuration of each paddle 202, which correspondingly increases the length and surface area of each of the paddles 202 contacting the material. The helical configuration of each of the paddles 202 also tends to chum the material, increasing the likelihood that particles of the material will contact and receive an electrostatic charge from the charging element 202.

Referring now in particular to FIGURE 6, the lateral surfaces of each paddle 202 form a pair of shoulders 204. The shoulders 204 form troughed or concave surfaces extending along the length of each of the paddies 202. These surfaces 206 assist in entraining particulate material between the paddles 202 and inhibit the passage of particulate material over the tips 208 of the paddles 202, particularly when the portion of the paddle holding particulate material is not facing downwardly, such as at the lowest point in the rotation of that portion of each paddle 202. This configuration tends to hold and transport material along the length of the charging element 200 when not adjacent the underiying discharge slot 54.

Once positioned near the lowest point in rotation of the charging element 200, the entrained material is dispensed by falling from between the paddies 202 through the underlying discharge slot 54. Each of the paddles 202 tapers radially beyond the shoulders 204 to form a tip 208 extending along the length of each paddle 202, thereby widening the opening between adjacent paddles 202 through which entrained material falls as the lowest point of rotation of that portion of the charging element 200 is approached. The outward taper of the tips 208 also urges material falling away from the charging element 200 and toward the underlying discharge slot 54, particularly by a wiping action of those surfaces of the paddle 202 facing the direction of rotation of the charging element 200.

FIGURE 7 illustrates the construction of the support brackets 60 secured about the first transport section 38 of the applicator arm 18. Each of the support brackets 60 is manufactured from UHMW plastic, and comprises two halves that may be separated to facilitate removal from and adjustment of position on the first transport section 38. When secured together, the halves of each the support bracket 60 form apertures 116, 118 and 120. Aperture 120 is sized to surround and grip the outer surface of the first transport section 38 when both halves of each support bracket 60 are secured together. Apertures 118 and 120 are sized to support the charge lead 58 and air delivery line 64, respectively.

Both halves of each support bracket 60 are secured together by bolts 123 which engage threaded apertures 122 of one half of the support bracket 60. When threaded into apertures 122, the heads of each bolt engage the shoulders of counter-sunk boreholes 124, drawing the halves of the support brackets 60 about the first transport section 38. The apertures 122 and the boreholes 124 are sized to recess the tightening bolts below the surface of the support brackets 60 when fully tightened.

FIGURE 8 illustrates in detail the construction of the support bracket 62 secured to the second transport section 40. The support bracket 62 is manufactured from UHMW plastic and includes an aperture 128 sized to slide over the outer surface of the second transport section 40. A threaded aperture 130 extending between the aperture 128 and the lower surface of the support bracket 62 accommodates a set screw 126 that can be tightened to engage the second transport section 40 and secure the support bracket 620 in a desired position. Positioned above the aperture 128 is a milled slot 132 for receiving and supporting the charge lead 58. Positioned above the slot 132 is a milled slot 134 for receiving and supporting the air delivery line 64. The slots 132 and 134 facilitate disconnection of the charge lead 58 and air delivery line 64.

It will be apparent that the length of the second transport section 40 and the delivery auger 24 may be varied to modify the overall length of the applicator arm 18. This may be desirable to accommodate use of the applicator 10 with tumbler drums 23 (FIGURE 1 ) and other devices of various types and sizes. In the event of such a length variation, the charge lead 58 and the air delivery line 64 are flexible and of sufficient length to be slid through the support members 60 in accordance with the length of the applicator arm 18 desired. A sufficient length of both the charge lead 58 and the air delivery line 64 is provided to allow a range of such adjustment. FIGURES 9A, 9B and 10 schematically illustrate the circuitry of the control system 20 and a control panel 136 of the electrostatic applicator 10. The control panel 136 is mounted on an enclosure 138 which, as is shown in FIGURE 1, is mounted in turn on the seasoning bin 14. The circuitry shown in FIGURES 9A and 9B is housed primarily in the enclosure 138 and processes commands received from the control panel 136. Identical components of the control panel 136 and control circuitry are identified with the same reference numeral in FIGURES 9A, 9B and 10.

Mounted on the control panel 136 are a number of control components and indicators. A systems power switch 140, is a dual position switch for providing 120v, 60Hz, single-phase power to the control system 20 when rotated from an "off to an "on" position. A red indicator light 142 mounted above the switch 140 is lit when power is supplied to the control system 20. Also mounted on the control panel 136 is a three-position, rotatable air dispenser switch 144 which receives power from the system power switch 140. The air dispenser switch

144 and associated circuitry control the operation of an air dispenser solenoid valve 146, shown mounted to the bin 14 in FIGURE 1. Referring briefly to FIGURE 1 , the solenoid valve 146 receives air from a local supply (not shown), through a filter 148. When actuated to an open position, the solenoid valve 146 supplies compressed air to an air pressure regulator/gauge assembly 150 for controlling the pressure of air supplied to the air delivery line 64. The regulator/gauge assembly 150 is preferably adjusted between 2 and 4 psig.

The air dispenser switch 144 may be positioned in the "off" , "hand" and "auto" positions, in the "off position, the solenoid value 146 is closed, interrupting the flow of air through the air delivery line 64. When the switch 144 is placed in the "hand" position, the solenoid valve 146 is held open continuously to provide regulated air to the air delivery line 64. in the "auto" position, the air dispenser switch 144 opens the solenoid valve 146 to provide air to the air delivery line 64 only if power is supplied to the drive assembly 16 from the drive assembly speed controller 22. This is accomplished by interposing a double-pull/double-throw

120v control relay 152 between the switch 144 and the solenoid valve 146. The control relay 152 is closed upon actuation of the motor 28. A digital LED microamp meter 154 is mounted on the enclosure 138 above the control panel 136 for indicating the amperage drawn by the control circuitry shown in FIGURES

9A and 9B.

Interfacing the command circuitry with electrostatic charge generation circuitry is a control voltage transformer 158. The transformer 158 receives power when the switch 140 is placed in the "on" position and energizes the electrostatic charge generation circuitry by the actuation of both the system power switch 140 and a static electricity control switch 156. Similarly to the three positions of the air dispenser switch 144, the static electricity control switch 156 energizes the control voltage transformer 158 continuously when positioned in the "hand" position, energizes the transformer 158 only if power is supplied to the motor 28 by the speed controller 22 if placed in the "auto" position, and de-energizes the transformer 158 when placed in the "off position. A control relay 164 interposed between the control switch 156 and the transformer 158 is mounted within the speed controller 22 and is energized to complete the associated circuit only when power is supplied by the speed controller 22. The electrostatic charge generation and control circuitry of FIGURES 9A and 9B is powered by a high voltage AC power supply 160. The primary function of the circuitry depicted in FIGURES 9A and 9B is to provide the charge lead 58 with an electrostatic charge. The charge is variable by adjustment of the circuitry between Ov to 100,000v DC. The DC voltage applied is varied by a voltage regulator 162 mounted on the enclosure 138 above the control panel 136. A red indicator light 142 mounted on the control panel 136 indicates that the high voltage power supply 160 has been applied to the circuitry shown in FIGURES 9A and 9B. Once an electrostatic charge generated by the control system 20 has reached the voltage to which the voltage regulator 162 is adjusted, a green indicator light 166 mounted on the control panel 136 is energized. An auto transformer 168 for generating an electrostatic charge is connected to the voltage regulator 162 and includes a number of output terminals 170. A terminal is selected that does not have an output exceeding 100,000v DC. The microamp meter 154 (shown in both of FIGURES 9A and 9B) is interposed between the high voltage supply 160 and an overload control board 172 for monitoring the current drawn by generation of the selected electrostatic charge. The circuitry shown in FIGURE 9A and 9B typically draws approximately 50-100 micro amps. The overload control board 172 is set to interrupt generation of an electrostatic charge by the circuitry at a load of 250 microamps. In the event the set point of the overload control board 172 is reached, generation of an electrostatic charge is interrupted by a control relay 173 and an overload indication is given by a red warning light 174 mounted on the control panel 136. The overload control board 172 and overload indicator light 174 may be tested by depressing an overload test button 176 mounted on the control panel 136. A second stage transformer 178 is included to provide low voltage transformation of the electrostatic charge, after processing by the high voltage transformer 168, to further steady the electrostatic charge generated. The applicator 10 and circuitry shown in FIGURES 9A and 9B are directly connected to a grounding rod 180 driven into the earth.

In operation of the electrostatic applicator 10, seasonings, such as salt, spices or other flavorings are loaded into the bin 14. The desired electrostatic charge is adjusted via the voltage regulator 162 on the enclosure 138. It will appreciated that the optimum voltage will vary, depending upon factors such as the electrical conductivity, grain size and desired flow rate of the seasoning applied.

The flow rate of seasoning dispensed by the applicator 10 may be varied by adjustment of the speed controller 22 and the pitch of the delivery auger 24. The speed controller 22 controls both the actuation and speed of the motor 28 of the drive assembly 16. Variation of the speed of the motor 28 in turn varies the rotational speed of the delivery auger 24 to adjust the speed at which seasonings are conveyed by the delivery auger 24 through the applicator arm 18. Varying the pitch of the winding of the delivery auger 24 correspondingly varies the rate which seasoning is driven through the arm 18 by the delivery auger 24, with any given speed of the motor 28.

Operation is initiated by actuation of the control system power switch 140.

The air dispenser switch 144 and static electricity control switch 156 are adjusted to select either continuous operation in the "hand" mode or operation only with actuation of the motor 28 in the "auto" mode. The motor 28 and drive assembly

16 are actuated by the speed controller 22.

When actuated, the drive assembly 16 rotates the delivery auger 24 and mixing auger 26 at a rate selected by the speed controller 22. The mixing auger

26 stirs and brings the seasoning within the bin 14 into contact with the delivery auger 24, promoting continuous flow of seasoning without clumps from the bin 14 through the action of the delivery auger 24. The first and second transport sections 38 and 40 control delivery of the seasonings, by holding the seasonings against the winding of the delivery auger 24 and containing the seasonings entrained by the delivery auger 24. Enclosing the seasoning within the transport sections 38 and 40 prevents dispersion of the seasonings into the atmosphere, onto surrounding equipment and around the work area.

The seasoning is conveyed to the end of the applicator arm 18 in a substantially continuous, controlled flow rate, until reaching the charging element 50. As the charging element 50 is rotated by the delivery auger 24, each of the paddies 52 in turn engages seasoning received from the end of the delivery auger 24. Contact between the paddles 52 of the charging element 50 imparts a charge to the seasoning received from the control system 20 via the charge line 58. Direct contact between the seasoning and the charging element 50 causes a greater and more uniform charge to be imparted to the seasoning. The paddies

52 lift the seasoning as the charging element 50 is rotated, until the seasoning reaches and passes through the discharge slot 54. The seasoning falls from the discharge slot 54, where it adheres to food products having an opposite or neutral charge. Any seasoning passing beyond the discharge slot 54 escapes from the end piece 56, through the release slot 110 and onto the food products below.

Air is blown past the discharge slot 54 by the air delivery system 66 to aid in seasoning dispersion and to direct the seasoning toward the underlying food products. Any clumps of seasoning encountering the air flow of the air direction system 66 tend to be broken into their constituent particles, creating a finer and more uniform application of seasoning to the food product. The flow of air from the air direction system 66 may be adjusted as desired for a particular application.

The foregoing invention thus provides an electrostatic seasoning application system in which the charge, flow rate and application of seasoning are greatly improved. Although preferred embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing Detail

Description, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements and modifications of parts and elements without departing from the spirit of the invention.

Claims

CLAIMS:

1. An apparatus for dispensing particulate material, comprising: conduit means for containing and transporting particulate material, the conduit means having an opening through which the material can be dispensed; transport means within the conduit means for moving the material through the conduit to a selected location within the conduit; charging means positioned at least partially within the conduit and adjacent the conduit means opening for receiving material from the drive means, contacting and electrostatically charging the material received, and moving the electrostatically charged material to a position immediately adjacent the conduit means opening where the charged material is dispensed.

2. The dispensing apparatus of Claim 1, wherein the charging means incudes a rotatable charging element which electrostatically charges particulate material while moving the material from the drive means to a position adjacent the conduit opening for dispensation.

3. The dispensing apparatus of Claim 2, wherein the charging element includes at least one surface adapted to engage and move particulate material received from the drive means as the charging element is rotated, thereby imparting an electrostatic charge to the material.

4. The dispensing apparatus of Claim 2, wherein the charging element incudes one or more paddles for engaging and moving particulate material as the charging element is rotated, thereby contacting and electrostatically charging the material.

5. The dispensing apparatus of Claim 4, wherein at least one of the paddies of the charging element is helical, for moving particulate material received from the transport means further within the conduit means.

6. The dispensing apparatus of Claim 1 , wherein the transport means includes an auger rotated to move particulate material through the conduit means to the charging means.

7. The dispensing apparatus of Claim 6, wherein the charging means is rotated by the auger of the transport means to move particulate material to the opening of the conduit means.

8. The dispensing apparatus of Claim 7, wherein the charging element includes at least one surface adapted to engage and move particulate material received from the transport means as the charging element is rotated, thereby imparting an electrostatic charge to the material.

9. The dispensing apparatus of Claim 7, wherein the charging element includes one or more paddles for engaging and moving particulate material as the charging element is rotated, thereby contacting and electrostatically charging the material.

10. The dispensing apparatus of Claim 9, where at least one of the paddles of the charging element is helical, for moving particulate material received from the transport means further within the conduit means.

11. The dispensing apparatus of Claim 10, further comprising: a feeder means for supplying particulate material to the transport means auger; and mixing means within the feeder means for stirring particulate material within the feeder means.

12. The dispensing apparatus of Claim 11, wherein the mixing means includes a stirring auger having at least one helical winding surrounding a portion of the transport auger.

13. An apparatus for dispensing particulate material, comprising: a length of conduit having an opening extending through the side wall of the conduit; and a dispensing element mounted within the length of conduit adjacent the conduit opening for rotation to move particulate material within the conduit to the conduit opening.

14. The apparatus of Claim 13, wherein the dispensing element includes at least one displacing surface for moving particulate material transversely about the inner wail of the conduit as the element is rotated to place the material adjacent the opening for dispensation.

15. The apparatus of Claim 14, wherein the dispensing element includes a shaft and at least one paddle forming the displacing surface for moving particulate material transversely abut the inner wall of the conduit.

16. The apparatus of Claim 14, wherein the conduit is positioned such that the conduit opening through which the particulate material is dispensed is disposed above the lowest point of the conduit adjacent the dispensing element, such that particulate material is contacted by and moved to some extent by the dispensing element before passing through the opening.

17. The apparatus of Claim 16, wherein the dispensing element extends longitudinally within the conduit and includes at least one paddle forming the displacing surface for contacting and moving particulate material transversely within the conduit to the conduit opening.

18. The apparatus of Claim 17, wherein the paddle of the dispensing element is aligned with the longitudinal axis of the element.

19. The apparatus of Claim 17, wherein the paddle of the dispensing element extends helically along the element.

20. The apparatus of Claim 17, wherein the paddle of the dispensing element is not aligned with the longitudinal axis of the element.

21. The apparatus of Claim 13, further comprising electrostatic charging means for imparting an electrostatic charge to the dispensing element, whereby particulate material contacted by the dispensing element becomes electrostatically charged before passing through the conduit opening.

22. The apparatus of Claim 21 , wherein the electrostatic charging means includes an electrical contact for imparting an electrostatic charge to the dispensing element and the apparatus further comprises support means for holding the electrical contact against the dispensing element as the element rotates.

23. The apparatus of Claim 22, wherein the dispensing element and conduit opening are positioned adjacent one end of the conduit, and wherein the support means forms an end of the conduit and supports the dispensing element for rotation in electrical continuity with the electrical contact of the electrostatic charging means.

24. The apparatus of Claim 23, wherein the support means forms an escape opening for allowing the passage of particulate material not previously dispensed by the dispensing element through the conduit opening.

25. The apparatus of Claim 13, wherein the length of conduit includes an escape opening for allowing discharge from the conduit of particulate material passing beyond the opening in the sidewail of the conduit.

26. The apparatus of Claim 25, wherein the escape opening extends about the sidewall of the conduit.

27. A device for electrostatically charging a stream of particulate materials, comprising: an electrically conductive charging element positioned at least partially in the path of the stream of particulate materials; support means supporting the charging element for rotation; the charging element having a surface extension in at least one location for diverting the stream of particulate material in the direction of rotation of the element; and charge control means for applying an electrostatic charge to the electrically conductive charging element.

28. The device of 27, wherein the rotational axis of the charging element is not positioned perpendicular to the direction of flow of the particulate stream, such that the surface extension diverts the material in a direction at least partially perpendicular to the direction of material flow as the charging element is rotated.

29. The device of Claim 27, wherein the rotational axis of the charging element is positioned in substantial alignment with the direction of flow of the particulate stream, such that the surface extension diverts the material in a direction at least partially perpendicular to the direction of material flow as the charging element is rotated.

30. The device of Claim 27, wherein the surface extension is longitudinally aligned with the rotational axis of the charging element.

31. The device of Claim 30, wherein the surface extension constitutes a portion of a paddle.

32. The device of Claim 27, wherein the surface extension is not iongitudinally aligned with the rotational axis of the charging element.

33. The device of Claim 32, wherein the surface extension extends helically about the longitudinal axis of the charging element.

34. The device of Claim 33, wherein the surface extension forms a helical winding.

35. A particulate material dispensing apparatus, comprising: a tube for conveying particulate material; a transport means at least partially within the tube for rotation to transport particulate material through the tube; a charging means at least partially within the tube for rotation with the transport means to contact, electrostatically charge and dispense particulate material from the dispensing tube.

36. The apparatus of Claim 35, wherein the transport means is electrically non-conductive relative to the charging means, to isolate the electrostatic charge of the charging means.

37. The apparatus of Claim 35, wherein the dispensing tube is electrically non-conductive relative to the charging means, to isolate the electrostatic charging means.

38. The apparatus of Claim 35, wherein the transport means and dispensing tube are electrically non-conductive relative to the charging means to isolate the electrostatic charge of the charging means.

39. The apparatus of Claim 36, wherein the transport means includes an auger rotated about its longitudinal axis.

40. The apparatus of Claim 35, wherein the charging means includes an electrically conductive auger mounted for rotation by the transport means.

41. The apparatus of Claim 40, wherein the dispensing tube is electrically non-conductive relative to the auger of the charging means.

42. The apparatus of Claim 41 , wherein the transport means includes an auger electrically non-conductive relative to the auger of the charging means.

43. A charging element for electrostatically charging particulate materials, comprising: an electrically conductive body having at least one axis of rotation; at least one helical extension formed by the surface of the body having a helical axis substantially parallel to the rotational axis of the body; drive means for rotating the body; and electrostatic charging means for imparting an electrostatic charge to the body as the body rotates.

44. The charging element of Claim 43, wherein the helical extension includes a concaved surface for contacting particulate material.

45. The charging element of Claim 43, wherein the helical extension includes a helical paddle.

46. The charging element of Claim 45, wherein the paddle includes a concave surface.

47. The charging element of Claim 45, wherein the helical paddle tapers radially.

48. The charging element of Claim 47, wherein the helical paddle includes a concave surface.