Weighing apparatus and conveyors systems incorporating a weighing apparatus

A weighing apparatus comprising a weigh deck, one or more load cells, and two staging bars. The weighing apparatus is configured to be installed in an existing conveyor system having a frame and a conveyor belt so that the weigh deck is generally flush with the frame and the weigh deck and the staging bars are positioned underneath the conveyor belt. The staging bars are positioned to mitigate weight measurement variations produced by the conveyor belt. In many cases, the staging bars are vertically adjustable. One or more weigh bridges can be incorporated into a production line or conveyor system.

FIELD OF THE INVENTION

The invention relates to weighing apparatus and conveyor system for weighing materials. In some cases, a weighing apparatus and conveyor system is provided for weighing a continuous flow of material.

BACKGROUND

Various materials are conveyed by conveyor systems as a continuous flow of material. For example, bulk materials can be transported as a continuous flow of material through a conveyor system. Bulk materials can include loose materials such as grain, gravel, and coal or other materials such as dough. Dough is often placed through an extruding apparatus and is extruded as a continuous sheet or ribbon of dough. This continuous sheet of dough can then be transported through a conveyor system where various operations are performed on the dough. Often times, it is necessary to weigh a continuous flow of material as it moves through a conveyor system. The present invention provides an economical and practical weighing apparatus and conveyor system for weighing a continuous flow of material.

SUMMARY OF THE INVENTION

A weighing apparatus is provided that can be installed in a new conveyor system or advantageously retrofitted on an existing conveyor system in a production line for weighing a continuous flow of material. Many existing production lines with conveyor systems take up a lot of space in a manufacturing facility. Commonly, production lines are custom made to fit limited space in existing manufacturing facilities. As such, it is impractical and uneconomical to replace existing conveyor systems with commercial conveyor systems that have built-in weighing systems. The present weighing apparatus is desirable because one or more can be installed in any type of conveyor system.

The weighing apparatus is configured to weigh a continuous flow of material. As used herein, the term “continuous flow of material” refers to an uninterrupted flow of material that is conveyed through a conveyor system. One exemplary characteristic of a continuous flow of material that can be processed on the weighing apparatus is a material that is connected to or continuous with material both in front of the weighing apparatus and behind the weighing apparatus. The continuous flow of material can be grain, gravel, coal, dough or another bulk material that is transported in a continuous, uninterrupted manner. In some cases, the material is a continuous sheet of dough. In many cases, the continuous flow of material is a material having a weight of about 0.02 lb/ft2(0.1 kg/m2) to about 150 lb/ft2(732.4 kg/m2) as it is conveyed through a conveyor system. The weighing apparatus is particularly adapted for weighing a continuous flow of material that is lightweight. As such, in certain cases, the material is a lightweight material having a weight of less than 10 lb/ft2(48.8 kg/m2) or less than 5 lb/ft2(24.4 kg/m2). It is difficult to measure a continuous flow of lightweight material because less weight generally leads to a higher inaccuracy in weight measurements. However, the weighing apparatus is capable of accurately measuring a lightweight continuous flow of material. In certain cases, the continuous flow of material has an actual weight, and the weighing apparatus obtains a measured weight that is approximately 80% of the actual weight. Through a linear regression model, the actual weight can be predicted within about ±4% of the actual weight.

The weighing apparatus can allow for automated weighing of a continuous flow of material. This is advantageous over prior weighing methods which involve manual methods of weighing the material, which require stoppage of the process or flow to obtain samples, or require unnecessary handling of samples. For example, in prior operations involving continuous sheets of dough, an operator periodically samples a sheet of dough by cutting small samples from the dough sheet and measures them offline. The operator then uses these measurements to estimate the entire weight (e.g., in lb/ft2) of the continuous sheet on the conveyor line. Such prior manual weighing methods are cumbersome, time-consuming, and allow room for operator-error. Additionally, such prior manual methods assume that the entire continuous flow of material on the conveyor line is uniform and thus the sample measurements are representative of the entire flow of material. The weighing apparatus allows for automated weighing, which remedies the problems seen with manual weighing methods.

Embodiments of the weighing apparatus includes a weigh deck, one or more load cells coupled to the weigh deck, and at least two staging bars coupled to the weigh deck. The weighing apparatus can be installed in an existing conveyor system so that the weigh deck and at least two staging bars are positioned underneath a conveyor belt. The weigh deck has a front end, a back end, and two side ends. One staging bar is mounted so that it is adjacent to and parallel to the front weigh deck end. Likewise, the other staging bar is mounted so that it is adjacent to and parallel to the back weigh deck end. In many cases, the staging bars are also spaced from each of the front end and the back end. The staging bars are vertically adjustable so that they can be positioned to mitigate weight variations produced by the conveyor belt. In many cases, the staging bars are positioned so they are spaced vertically from (i.e., higher than) the weigh deck. For example, the staging bars can be positioned so they are either flush with the weigh deck or less than ⅛ inch higher than the weigh deck for some applications. In the illustrated embodiment, two staging bars are used. Of course, more than two staging bars can be used in other embodiments.

In another embodiment according to the invention, a conveyor system is provided. The conveyor systems includes a frame, a conveyor belt that moves over the frame and conveys a continuous flow of material and one or more weighing apparatus. The weighing apparatus measures weight of the continuous flow of material being conveyed by the conveyor belt and comprises a weigh deck, one or more load cells, and two staging bars. The weighing apparatus is mounted to the frame so that the weigh deck is generally flush with the frame; and the weigh deck, the one or more load cells, and the two staging bars are positioned underneath the conveyor belt to mitigate weight measurement variations produced by the conveyor belt.

In yet another embodiment according to the invention, a conveyor system for automatically processing a continuous sheet of dough is provided. The conveyor system of this embodiment includes a conveyor line having a conveyor belt that conveys a continuous sheet of dough, one or more weighing apparatus, a processing apparatus that processes the continuous sheet of dough, and at least one controller that receives weight measurements from at least one weighing apparatus and uses the weight measurements to provide feedback to the processing apparatus. The one or more weighing apparatus measure the weight of the continuous sheet of dough being conveyed by the conveyor belt, is positioned underneath the conveyor belt, and is comprised of a weigh deck, one or more load cells, and the two staging bars. The two staging bars mitigate weight measurement variations produced by the conveyor belt.

DETAILED TECHNICAL DESCRIPTION

The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the present invention. Examples of constructions, materials, dimensions, and manufacturing processes are provided for selected elements, and all other elements employ that which is known to those of skill in the field of the invention. Those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized.

FIGS. 1-6illustrate one embodiment of a weighing apparatus10. The weighing apparatus10includes a weigh deck12having a front end102, a back end104, and two side ends106,108. The weighing apparatus10further includes four load cells14,16,18,20. Load cells14,16are coupled to the weigh deck side end106and load cells18, are coupled to the weigh deck side end108. In the illustrated embodiment, load cell mounts34,36are used to couple the load cells to the side ends106,108of the weigh deck12. For example, the load cell mount34can first be mounted to the side end106and then load cells14,16can then be mounted to the load cell mount34. Likewise, the load cell mount36can first be mounted to the side end108and then load cells18,20can then be mounted to the load cell mount36. Of course, any other mechanism of coupling the load cells to the weigh deck side ends106,108can also be used.

The load cells14,16,18,20are of any type that can measure a continuous flow of material having a weight between about 0.02 lb/ft2and about 150 lb/ft2. In some cases, the load cells14,16,18,20are sized to weigh up to 225 pounds, up to 110 pounds, or perhaps up to 44 pounds of material. The load cells14,16,18,20each include load sensors26,28,30,32that measure weight placed on the weigh deck12. The load sensors26,28,30,32input weight measurements to a controller (not shown). The controller then uses the weight measurements to provide a variety of functions. In many cases, each load sensor26,28,30,32obtains a separate weight measurement and provides these to the controller. The controller then takes the four weight measurements and computes an average weight measurement, for example in real time, for the continuous flow of the material.

The weighing apparatus10also includes two staging bars22,24with one mounted adjacent to and parallel to each of the front end102and the back end104of the weigh deck12. The staging bars22,24are also typically spaced away from the front end102and the back end104of the weigh deck12, although this is not required. When the weighing apparatus10is ultimately installed in an existing conveyor system, the weigh deck12and the staging bars22,24will be positioned underneath a conveyor belt (not shown). The conveyor belt will run directly over and contact the weigh deck12and the staging bars22,24under load. The staging bars22,24are also vertically adjustable so that they can be positioned to mitigate weight variations produced by the conveyor belt. The staging bars22,24are positioned to be either flush with or slightly higher than the weigh deck.

In the illustrated embodiment, the staging bars22,24are mounted using four top staging bar mounts46,48,50,52, four bottom staging bar mounts54,56,58,60, four adjustable screw assemblies62,64,66,68, and two load cell mounts34,36. Specifically, one end of staging bar22is mounted to the top staging bar mount48and the other end of the staging bar22is mounted to the top staging bar mount52. Likewise, one end of staging bar24is mounted to the top staging bar mount46and the other end of the staging bar24is mounted to the top staging bar mount50. In some cases, the top staging bar mounts46,48,50,52are integral to each end of the staging bars22,24. That is, the staging bars22,24have ends configured as and part of the top staging bar mounts.

The bottom staging bar mounts54,56,58,60are mounted to the load cell mounts34,36. Specifically, the load cell mount34has a first end38and a second end40. The bottom staging bar mount54is coupled to the first end38of the mount34. Likewise, the bottom staging bar mount56is coupled to the second end40of the mount34. Additionally, the load cell mount36has a first end42and a second end44. The bottom staging bar mount58is coupled to the first end42of the mount36. Likewise, the bottom staging bar mount60is coupled to the second end44of the mount36.

Each top staging bar mount46,48,50,52is coupled to a corresponding bottom staging bar mount54,56,58,60using an adjustable screw assembly62,64,66,68. For example, the top staging bar mount46is coupled to the bottom staging bar mount54through the adjustable screw assembly62. The adjustable screw assemblies62,64,66,68allow for each staging bar22,24to be vertically adjustable. The bottom staging bar mounts54,56,58,60remain fixed in place whereas the adjustable screw assemblies62,64,66,68make the top staging bar mounts46,48,50,52(and thus the staging bars22,24) vertically adjustable relative to the bottom staging bar mounts54,56,58,60. Skilled artisans will understand that the illustrated adjustment mechanism is only one mechanism for vertically adjusting staging bars22,24and other adjustment mechanism can instead be used.

The weighing apparatus10can be configured to be installed in or on top of a conveyor system. In the illustrated embodiment, the weighing apparatus10has two conveyor system mounts94,96that are configured to be coupled to a conveyor line. Of course, the weighing apparatus can also be coupled to the conveyor line using other known mechanisms, such as an I-beam.

The weighing apparatus10can optionally include one or more level bars70,72,74that assist in installing the weighing apparatus10to an existing conveyor system. The level bars70,72,74help to ensure that the weigh deck12is generally flush with the existing conveyor line. In the illustrated embodiment, the level bar70includes a handle76and two dials86,88; the level bar72includes two handles78,80and a dial90; and the level bar74includes two handles82,84and a dial92. The one or more level bars70,72,74assist one in installing the weighing apparatus10. The dials86,88,90are depth gauges in some embodiments that show the difference, in fractions of an inch, between the height of the weigh deck to the staging bars. Once the weighing apparatus10has been installed, the level bars70,72,74can be removed. While three level bars are shown, skilled artisans understand that only one level bar may be used.

A conveyor system is also provided having a frame and a conveyor belt that moves over the frame to convey a continuous flow of material. The conveyor system also includes a weighing apparatus10that measures the weight of the continuous flow of material being conveyed by the conveyor belt. The weighing apparatus10can be of any embodiments already described and generally includes a weigh deck12, one or more load cells, and two staging bars. The weigh deck12, one or more load cells, and two staging bars are positioned underneath the conveyor belt.

The conveyor system also includes a controller, wherein the weighing apparatus10inputs weight measurements to the controller. The conveyor system can be part of any production line. The controller can be programmed to take weight readings continuously, intermittently or on-demand when prompted to do so by an operator. In some cases, the weighing apparatus10includes load cells each having load sensors that measure weight of the moving continuous flow of material. The load sensors input the weight measurements to the controller. The controller can also be coupled to other components of the conveyor system, wherein the controller uses inputted weight measurements to provide feedback to the other system components.

FIG. 7illustrates a conveyor system200having the weighing apparatus10shown inFIGS. 1-6installed therein. The conveyor system200has a frame202, wherein a conveyor belt204moves over the frame202. In this embodiment, the weighing apparatus10is mounted to the conveyor system frame202so that the weigh deck12is generally flush with the conveyor line. The weighing apparatus10is also positioned so that the conveyor belt204moves over the staging bars22,24and the weigh deck12.

The staging bars22,24help to obtain accurate weight measurements because they help negate the effects the conveyor belt tension or speed has on weight measurements. For example, conveyor belt speeds and belt tensions can sometimes cause inaccurate fluctuations in weight measurements. In many types of conveying systems, conveyor belt speeds and belt tensions often change during the conveying process, and these changes can in turn cause fluctuations in the weight measurements. However, the inventors have discovered that the use of adjustable staging bars22,24helps to offset negative or undesirable effects due to variations in conveyor belt speed and belt tension and helps to provide more accurate weight measurements.

With respect to belt tension, the staging bars22,24isolate the weighing apparatus10from upstream and downstream belt tension effects. In other words, the staging bars22,24isolate a smaller section of the overall conveyor line. If the belt tension is tightened or loosened, the effect on the weight measurement is minimal compared to if the staging bars22,24did not exist. If the staging bars22,24did not exist or were set lower than the weigh deck12, the effect of tightening or loosening the belt would be detected in the weight measurement.

The staging bars22,24also help to mitigate effects of weight on the conveyor line that is upstream or downstream of the weighing apparatus10. For example, the staging bars22,24help prevent upstream and downstream weight from being detected in the weight measurements. In other words, the staging bars22,24help to make sure the weighing apparatus10only detects weight that is being conveyed over the weigh deck12at the time of weighing.

Once the weighing apparatus10is installed so that the weigh deck12and staging bars22,24are underneath the conveyor belt204, the staging bars22,24may be adjusted as necessary to mitigate weight variations produced by the conveyor belt204. In some cases, the staging bars22,24are positioned so they are spaced away from the front end102and back end104of weigh deck12. In certain cases, the staging bars22,24have a topmost portion that is spaced from (i.e. higher than) a topmost portion of the weigh deck12. For example, the staging bars22,24can be adjusted so they have a topmost portion that is less than an inch higher than a topmost portion of the weigh deck12. In specific cases, the staging bars22,24can be adjusted so they have a topmost portion that is about 0.0001 inches higher than a topmost portion of the weigh deck12. The inventors have discovered that by positioning the staging bars22,24so that they are either flush with or slightly higher than the weigh deck12, the staging bars22,24pull the conveyor belt204slightly upward before the belt moves over the weigh deck under load, which helps to offset negative effects of variations in conveyor belt speeds and belt tensions.

The staging bars22,24can be vertically adjusted separately or together. That is the staging bars22,24can have the same position relative to the weigh deck12or different positions relative to the weigh deck12. For example, in some cases, the staging bars22,24are adjusted so that staging bar22has a bottommost portion that is spaced from the topmost portion of the weigh deck12by a predetermined length and the staging bar24has a bottommost portion that is spaced from the topmost portion of the weigh deck12by a length that is either larger or smaller than the predetermined length. In other cases, the staging bars22,24are adjusted so that both staging bars22,24have a bottommost portion that is spaced from the topmost portion of the weigh deck12by the same predetermined length.

A method of installing a weighing apparatus10in an existing conveyor system200is also provided. The method includes the steps of: providing a weighing apparatus10comprising a weigh deck12, one or more load cells, and two vertically adjustable staging bars22,24; installing the weighing apparatus10in an existing conveyor system200having a frame202and a conveyor belt204so that the weigh deck12is generally flush with the frame202and the weigh deck12and the vertically adjustable staging bars22,24are positioned underneath the conveyor belt204; and adjusting the vertically adjustable staging bars22,24so that the staging bars22,24are positioned to mitigate weight measurement variations produced by the conveyor belt204. In some cases, the step of adjusting the vertically adjustable staging bars comprises adjusting the staging bars22,24to be higher than the weigh deck12. In certain cases, the step of adjusting the vertically adjustable staging bars comprises adjusting the staging bars22,24to be less than ⅛ inch higher than the weigh deck12. In other cases, the step of adjusting comprises adjusting the stage bars22,24to different vertical heights relative to the weigh deck12.

In some cases, the conveyor system200is part of a dough production line and the continuous flow of material is a continuous sheet of dough.FIGS. 8-9each illustrate conveyor systems part that are of a dough production line that conveys a continuous sheet of dough. Each of these conveyor systems also have a weighing apparatus10installed therein.

FIGS. 8 and 9illustrate a dough production line section300that includes an extruding apparatus302followed by a conveyor system200including a weighing apparatus10. Dough products are produced by placing dough through the extruding apparatus302and extruding a sheet or ribbon of dough onto the conveyor belt system204, typically in a continuous flow. The conveyor system200includes a weighing apparatus10mounted therein so that the conveyor belt204moves over the weighing apparatus10. The conveyor belt204conveys the sheet or ribbon of dough over the apparatus10, which then obtains one or more weight measurements. The weight measurements are then inputted to a controller (not shown), which is in electronic communication with the extruding apparatus302and uses the weight measurements to provide feedback to the extruding apparatus302.

In some cases, the feedback instructs the extruding apparatus302to increase or decrease extrusion of dough. In other words, the feedback tells the extruding apparatus302to increase or decrease the mass flow of dough (e.g., in lbs/min) that exits the extruding apparatus302onto the conveyor belt204. For example, the controller can be configured to provide feedback to the extrusion apparatus302so that it extrudes a continuous sheet of dough having a predetermined weight measurement. If the weight measurements obtained are larger than the predetermined weight measurement set by the controller, the controller instructs the extruding apparatus302to increase extrusion of dough in order to produce dough having a lower weight measurement. Likewise, if the weight measurements obtained are smaller than the predetermined weight measurement set by the controller, the controller instructs the extruding apparatus302to decrease extrusion of dough in order to produce dough having a higher weight measurement. In certain embodiments, the controller uses one or more algorithms to provide feedback to the extruding apparatus302. The use of algorithms allows the controller to specifically control the amount of increase or decrease of dough extrusion, which makes it easier to obtain the predetermined weight measurement or set point.

In other embodiment, the weighing apparatus10can be used with a section of a dough production line300that includes a food deposition apparatus. For example, the section can include a conveyor system200including a weighing apparatus10followed by a food deposition apparatus. The food deposition apparatus can be any apparatus, e.g., a pump, that deposits food onto the dough sheet. For example, the food deposition apparatus can deposit food materials or particulates, such as shortening, flour, chocolate chips, raisins, oats and the like onto the dough sheet. In some cases, the food deposition apparatus is a shortening pump that deposits shortening onto the dough sheet. The weighing apparatus10mounted in the conveyor system200so that a conveyor belt204moves over the weighing apparatus10. As the conveyor belt204conveys the continuous sheet of dough over the weighing apparatus10, the weighing apparatus10obtains one or more weight measurements. The weight measurements are then inputted to a controller, which is in electronic communication with the food deposition apparatus and uses the weight measurement to provide feedback to the food deposition apparatus.

In some cases, the feedback instructs the food deposition apparatus to increase or decrease deposition speed of food. In certain cases, the controller uses one or more algorithms to provide feedback to the food deposition apparatus. For example, the algorithms can correlate different weight measurements with different food deposition speeds. Thus, as the dough sheet moves over the weighing apparatus10, the weighing apparatus10obtains different weight measurements that prompts the controller to in turn adjust the food deposition speed.

In yet other embodiments, the weighing apparatus10can be used with a section of a dough production line300that includes a reducing apparatus. For example, the section can include a conveyor system200including a weighing apparatus10followed by a reducing apparatus. The reducing apparatus is an apparatus that further rolls over and reduces dough sheet thickness. Again, the weighing apparatus10mounted in the conveyor system200so that a conveyor belt204moves over the weighing apparatus10. As the conveyor belt204conveys the continuous sheet of dough over the weighing apparatus10, the weighing apparatus10obtains one or more weight measurements. The weight measurements are then inputted to a controller, which is in electronic communication with the reducing apparatus and uses the weight measurement to provide feedback to the reducing apparatus.

In some cases, the feedback instructs the reducing apparatus to increase or decrease dough thickness. For example, the controller can be configured to provide feedback to the reducing apparatus so that it increases or decreases dough sheet thickness depending on the weight measurement obtained by the weighing apparatus10. Here too, the controller can use one or more algorithms to provide feedback to the reducing apparatus. For example, the algorithms can correlate different weight measurements with different rolling/reducing actions that produce different dough sheet thicknesses. For example, in some cases, the reducing apparatus includes two rollers. If the controller instructs the reducing apparatus to increase dough sheet thickness, the two rollers can move further apart from one another or perhaps roll the dough sheet more times. Likewise, if the controller instructs the reducing apparatus to decrease dough sheet thickness, the two rollers can move closer together or perhaps roll the dough sheet fewer times. The use of algorithms allows for the controller to specifically control the amount of increase or decrease in dough sheet thickness.

As shown, the present weighing apparatus10is useful in various conveyor systems200of a dough production line300. Final dough products sometimes experience variability in amounts of the deposited food materials. For example, shortening variability can sometimes occur during the conveying process if there are variations in the dough sheet. Variations can occur, for example, when a dough sheet has holes or wrinkles in it. As the dough sheet is conveyed past a shortening pump, the pump deposits shortening onto the sheet. If there are variations in the sheet, some parts of the sheet will have a lower or higher percentage of shortening to dough than other parts of the sheet. This can contribute to shortening variation in a final product. The above-described weighing apparatus10now makes it possible for existing conveyor systems to weigh continuous sheets of dough. Weight measurements obtained by the weighing apparatus10can be inputted to a controller which detects dough sheet variation and then provides feedback to dough production line components that can correct or account for these variations. Thus, the weighing apparatus10helps to reduce variation in a final product.

Conveyor systems or production lines according to embodiments of the invention may include one or more weighing apparatus and/or one or more controllers. A single weighing apparatus can be in electronic communication with a single controller or more than one controller which in turn can regulate one or more processing apparatus. If a plurality of weighing apparatus are staged along a productions line, they may be in electronic communication with a single controller, or each of them could be in separate communication with separate controllers, or more than one of the weighing apparatus could be in communication with one or more controllers, regulating single or multiple processing apparatus.

In the foregoing detailed description, the invention has been described with reference to specific embodiments. However, it may be appreciated that various modifications and changes can be made without departing from the scope of the invention as set forth in the appended claims.