Patent Application
20060228240
1. Field of the Invention
The present invention relates to a method and apparatus for pumping a product and, more particularly, but not by way of limitation, to pumping a product with a linear peristaltic pump.
2. Description of the Related Art
In an attempt to remain competitive in the industry of packaged foods and food type products, retailers are continually forced to evaluate their packaged foods, as well as their product dispensers. In attempts to maximize profits, retailers are moving to less expensive packaging on the food products they use. Many attempts have been made to simplify package loading and unloading in a dispenser; however, the added burden associated with complex packaging is indirectly passed on to the product.
The least expensive form of packaging currently on the market is a soft package with a fitting permanently affixed to one side. The fitting provides the user with a means to connect an evacuation apparatus to the package. In some instances, a pump is connected to the pouch, but invasive pumps in food product systems may create cleanliness problems, as they will require cleaning. As such, attempts have been made to create a disposable pump that requires no cleaning. While a pump that requires no cleaning is convenient, it is also more expensive.
Non-invasive pumps do not require cleaning, as they never touch the food product. The most commonly used non-invasive pump is a peristaltic pump. Use of a peristaltic pump requires a length of tubing be connected to a product package. The tubing is loaded in a trough around the perimeter of the peristaltic pump. The peristaltic pump further includes a set of rollers that move along the perimeter of the peristaltic pump. As the rollers compress the tubing, product is displaced when the roller set rotates.
While retailers like the package cost of a peristaltic type arrangement, the peristaltic pump is not usable in high accuracy applications. Problems with the peristaltic pump stem from the peristaltic pump being circular. As the tubing is wrapped around the peristaltic pump, the cross-section of tubing changes from a circular shape to a non-circular shape. Further, as a roller begins to engage the tubing, the tubing is compressed at the roller position, as well as in the general area of the roller. The compression of the tubing is therefore non-linear and inconsistent as a dispensing means.
Accordingly, a linear non-invasive peristaltic pump would be beneficial to retailers and product dispenser manufacturers.
In accordance with the present invention, a method and corresponding apparatus provide a non-invasive linear peristaltic pump with increased accuracy. Peristaltic pumps currently on the market are not linear, as the product tube is wrapped around a rotating carousel and restrained in a circular housing. As the product tube is stretched around the circular carousel, the inner passage of the product tube is no longer circular. As such, when the product tube in the peristaltic pumps is compressed, the output is non-linear. Therein, peristaltic pumps currently on the market are not useful in application where high accuracies are desired.
The present invention provides a high accuracy peristaltic pump with a linear stoke. A linear peristaltic pump includes a traction plate with a linear portion, at least one depressor and a driver. The depressor compresses the product tube between the linear portion and the depressor, such that an inner passage of the product tube is substantially sealed. The driver moves the depressor along the linear portion of the traction plate, such that a product tube located between the depressor and the linear portion is compressed along the linear portion. Another embodiment may include depressors attached to belts, wherein successive depressors may be driven along the linear portion to dispense or move product. Still another embodiment may include the use of a controller to conduct the dispensing operations.
It is therefore an object of the present invention to provide a linear, non-invasive pump for dispensing product.
It is further an object of the present invention to depress a product tube along a linear portion of a traction plate, such that product is moved in front of the depressor.
It is still further an object of the present invention to provide successive depressors along a linear path to dispense substantially any amount of product.
It is still yet further an object of the present invention to provide a method of dispensing product using the linear peristaltic pump.
Still other objects, feature, and advantages of the present invention will become evident to those of ordinary skill in the art in light of the following.
a illustrates a right side view of the linear peristaltic pump according to the second embodiment.
b provides a section view through the centerlines of the shafts according to the second embodiment.
a is a left-side view of the linear peristaltic pump according to the second embodiment.
b is a section view through the centerline of the belt assembly according to the second embodiment.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. It is further to be understood that the figures are not necessarily to scale, and some features may be exaggerated to show details of particular components or steps.
The preferred embodiment is a method and apparatus for dispensing products using a peristaltic pump that includes a straight or linear segment to provide a more consistent dispense. The linear peristaltic pump includes provisions for metering fluid products or semi-fluid products. The linear peristaltic pump is non-invasive to the product. As such, it may be utilized on wide ranges of food products and food product dynamics. Low viscosity products may flow to the pump freely; however, semi-viscous and high viscosity products may be dispensed with the assistance of an evacuation device to achieve acceptable evacuation parameters. The linear peristaltic pump is able to engage the product packaging used in existing peristaltic pump applications.
In the simplest form, a linear peristaltic pump 300 includes a traction plate 312, a depressor 356 and a driver 330, as shown in
The linear peristaltic pump 300 includes a loading position and a working position, wherein the depressor 356 and the traction plate 312 cooperate to expand or reduce the gap therebetween. In the loading position, the depressor 356 may or may not be in contact with the traction plate 312 or the product tube 310. A slight pressure on the product tube 310 during loading may be desirable to maintain feature locations. In the working position, the depressor 356 compresses the product tube 310 such that the inner passage is sealed off at the depressor 356 compression point as shown in
In operation, a product tube 310 is loaded into the gap, and the linear peristaltic pump 300 is moved into the working position, therein compressing the product tube 310 between the depressor 356 and the traction plate 312. Upon a dispense, the driver 330 forces the depressor 356 downward along the linear portion 311 of the traction plate 312. The depressor 356 therein continuously applies pressure to the product tube 310 as it moves from the upper end 313 to the lower end 314 of the linear portion 311. As the depressor 356 is moved toward the lower end 314 of the linear portion 311, a predetermined quantity of product in the product tube 310 is forced downward in front of the depressor 356. The driver 330 then releases the product tube 310 and returns the depressor 356 to the upper end 313 of the linear portion 311 of the traction plate 312. The product tube 310 is again depressed at the upper end 313 of the linear portion 311, therein closing off the inner passage of the product tube 310. This process may be repeated as desired to dispense a desired amount of product. The continued compression of the product tube 310 along a linear path provides a more consistent displacement of product, as the tube 310 and its inner passage are not stretched around a curved surface. This process may be used to evacuate product from a package or to move product to remote areas through the use of a hose.
While the depressor 356 compression point has been shown to rest at the upper end 313 of the linear portion 311, it may also be arranged such that the compression point is at the end of the dispense stroke. A compression point at the end of the dispense stroke leaves minimal product in front of the compression point, therein protecting the product in the tube behind the compression point from exposure to contaminants. Alternatively, a valve may be included to assist the depressor 356 in maintaining the product tube 310 closed and therein sealed from exposure to contaminants.
While this embodiment has been shown with a single depressor 356, it should be noted that more than one depressor 356 may be used to provide redundant seals or subsequent passes along the linear portion 311 of the traction plate 312. Multiple depressors 356 may or may not be connected together through the use of a belt or chain. A belt arrangement with multiple depressors 356 may provide a multitude of dispenses at will through the use of a controller and motor combination. The belt may essentially be any number of links, however, once a circular pattern is achieved, virtually any desired dispense amount may be achieved.
While this embodiment has been shown with a cylindrically shaped depressor 356, the shape of the depressor 356 may deviate based on the drive system device or product and tube choices.
As shown in
The base 111 includes a first face 115 and a second face 116, directly opposed to the first face 115. A first shaft aperture 114 and a second shaft aperture 118 extend from the first face 115 to the second face 116. The base 111 further includes a groove 117 having an inner periphery 197 and an outer periphery 198 on the first face 115 surrounding the shaft apertures 114 at a predetermined radius. The groove 117 has a depth suitable to provide restraint to captured dowel pins, such that the dowel pins are able to move along the groove 117. Each shaft aperture includes a counterbore 119 on the second face 116 concentric to the shaft aperture to accept a bearing 123 and a tolerance ring 124.
The motor assembly 120 includes a motor 121, a drive shaft 122, an idler shaft 125, the bearings 123, the tolerance rings 124 and a plurality of screws 127. The motor 121 includes a motor shaft 128 and a mounting plate 129. The tolerance rings 124 are shaped to fit in the counterbore 119. The bearings 123, having an inner periphery 145 and an outer periphery 144, are then pressed into the counterbores 119 in the first shaft aperture 114 and second shaft aperture 118, such that the outer periphery 144 engages the counterbores 119. The drive shaft 122 includes a bearing surface 150 adjacent to a shoulder 152. The shoulder 152 includes an aperture 151 to accommodate a setscrew 126. The drive shaft 122 further includes an aperture 153 to accept the motor shaft 128 and a drive portion 170 that includes a machined flat 171 for additional bearing surface. The motor shaft 128 includes a machined flat 149 to engage the setscrew 126. The drive shaft 122 still further includes a machined flat 148 for additional load bearing capacity and an end bearing surface 147 at the tip.
The motor shaft 128 is housed in the aperture 153 upon engagement with the drive shaft 122. The motor shaft 128 is secured to the drive shaft 122 with the setscrew 126. The drive shaft 122 is pressed into the bearing 123 in the base 111, such that the bearing surface 150 presses slightly into the inner periphery 145 of the bearing 123. The motor 121 is secured to the base 111 with a plurality of screws 127 that pass through a set of mounting holes 131 in the mounting plate 129 to engage mounting holes 146 in the second face 116 of the base.
The drive belt assembly 130 includes bottom endcaps 137, top endcaps 138, pin guides 134, a belt link assembly 135, drive gears 136, an intergear support guide 139 and a cover plate 140. The belt link assembly 135 includes belt links 154, dowel pins 155 and rollers 156. The belt links 154 each include a link body 160, a first end 157, a second end 158 and link tabs 163 and 168. The link tabs 163 and 168 lie perpendicular to the plane of the link body 160. Link tabs 163 protrude from the first end 157 and link tabs 168 protrude from the second end 158 of the link body 160. The link tabs 163 include an aperture 164 on each link tab 163 on the first end 157 and an aperture 167 on each link tab 168 on the second end 158. A radial edge 165 surrounds the apertures 164 and 167. On the first end 157, the link tabs 163 are oriented such that the apertures 164 are coaxial. The spacing between the link tabs 163 on the first end 157 is such that the roller 156, having an axial aperture 166, fits between the link tabs 163. The roller 156 is oriented coaxially to the apertures 164. On the second end 158, the spacing between the link tabs 168 allows the roller 156 and the link tabs 163 from the first end 157 of another belt link 154 to align between the link tabs 168. Once aligned, the dowel pin 155 is inserted through the aligned apertures. Illustratively, the dowel pin 155 passes through the aperture 167 from the second end 158, the aperture 164 from the first end 157, the axial aperture 166 of the roller, the second aperture 164 from the first end 157 and the second aperture 167 from the second end 158. The dowel pins 155 are centered in the apertures and protrude from the connection. In this type of arrangement, the belt links 154 may cooperatively engage to form a belt type arrangement and individually rotate about the dowel pins 155. While this embodiment has been shown with five belt links 154, it should be clear to one skilled in the art that the quantity of belt links 154 in the belt link assembly 135 may vary.
The belt links 154 further include a drive surface 159 having a plurality of tread protrusions 161 aligned parallel to the axis of the installed dowel pins 155. The tread protrusions 161 engage the drive gears 136. In this embodiment, the drive gears 136 are injection-molded components used to transfer the force applied from the drive shaft 122 to the drive belt assembly 135. The drive gears 136 include a shaft aperture 169 containing a flat 174 to engage the machined flat 148 of the drive shaft 122. The drive gears 136 include a circular outer perimeter 172 with radial insets 173, three in this preferred embodiment, to provide clearance for the rollers 156 on assembly. The drive gears 136 further include tread 175 on the outer perimeter 172 to engage the drive surface 159 of the belt links 154. As the drive gears 136 are injection molded, the component is cored to produce a relatively consistent wall thickness. As such, inner core pockets 176, substantially symmetrical, exist on both ends of the drive gears 136. The inner core pockets 176 engage the endcaps 137 and 138.
In this preferred embodiment, the endcaps 137 and 138 are injection-molded components. The endcaps 137 and 138 include an outer periphery 178 and an aperture 179 to provide passage for the drive shaft 122. Two endcaps are required per drive gear 136, the top endcap 137 and the bottom endcap 138. The endcaps 137 and 138 include a gear side 180 and a guide side 181. The gear side 180 includes a protrusion 199 in the shape of the inner core pocket 176 of the drive gear 136 that is used to align the endcaps 137 to the drive gear 136. The outer periphery 178 of the endcaps 137 and 138 further includes radial insets 182 to provide clearance for the dowel pins 155. The guide side 181 of the endcaps 137 and 138 includes a cylindrical protrusion 183 that is used to engage the pin guides 134.
The pin guides 134 are thin, flat components used to impart correct spacing between the drive gears 136. The pin guides 134 include two apertures 184, designed to fit over the cylindrical protrusion 183 of each endcap 137 and 138. The pin guides 134 further include alignment apertures 185 to accept an alignment pin 188 and a clearance aperture 186 to accept a screw 142. An outer periphery 206 of the pin guide 134 mirrors an inner periphery 197 of the groove 117 in the base 111.
The intergear support guide 139, in this preferred embodiment, is an injection-molded component used to maintain the spacing between the linear peristaltic pump components. The intergear support guide 139 includes a raised section 200 with a symmetrical flange 201 at each end. The intergear support guide 139 includes a scalloped section 202 on each side to provide clearance for the rotating gears 136. The intergear support guide 139 further includes a flat 205 on the edge of each flange 201. The intergear support guide 139 still further includes two apertures 204 for alignment pins 188 and a plurality of apertures 203 to accept the fasteners 142.
The cover plate 140 captivates the drive belt assembly 130 and associated components when the fasteners 142 are secured. The cover plate 140 is an injection-molded component having a gear side 189 and an outer side 190. The gear side 189 of the cover plate 140 includes a groove 191 symmetrical to the groove 117 in the base 111. The groove 191 surrounds two blind holes 192 on the gear side 189 of the cover plate 140. The blind holes 192 are used to accept a bearing 193. The cover plate 140 further includes alignment apertures 194 and a fastener aperture 195.
On assembly, the bearings 123 and the tolerance rings 124 are pressed into the base 111. The idler shaft 125 is then pressed into the bearing 123 in the base 111. The motor shaft 128 is inserted into the aperture 151 in the drive shaft 122 and secured with the setscrew 126. The motor assembly 120 is then pressed into the bearing 123 which was previously pressed in the base 111. The mounting plate 129 is then secured to the base 111 using screws 127. Once assembled, the drive shaft 122 and the idler shaft 125 protrude through the first face 115 of the mounting base 111. The alignment dowel pins 188 are then pressed into the alignment pin aperture 187 on the first face 115 of the base 111.
Once the motor assembly 120 has been assembled to the mounting frame assembly 110, the spring washers 143 may be assembled onto the protruding shafts. One of the pin guides 134 is then assembled on the alignment pins 188, followed by the standoff 139. An endcap 138 is then added to each shaft 122 and 125, such that the cylindrical protrusions 183 fit within the aperture 184 of the pin guide 134. The gears 136 slide onto the shafts 122 and 125 and engage the gear side 180 of the endcaps 137 and 138. Installation of the gears 136 is followed by the installation of the belt link assembly 135. The belt link assembly 135 can now be placed around the gears 136 and the standoff 139, such that the drive surface 159 of the belt links 154 engages the treads 175 of the gears 136, and the radial insets 173 of the gears 136 engage the rollers 156. When seated properly, the protruding dowel pins 155 of the belt link assembly 135 engage the groove 117 located in the base 111.
Installation of the belt link assembly 135 is followed by the installation of the top endcaps 138. The gear side 189 of the top endcap 137 engages the innercore pockets 176 of the gears 136. The radial insets 173 and 182 of the endcaps 137 and 138 engage the belt link assembly pins 155 to maintain tension in the belt link assembly 135. The pin guide 134 is then installed such that the alignment apertures 185 fit around the alignment pins 188. In this arrangement, the cylindrical protusions 183 of the top endcaps 138 fit within the apertures 184 of the pin guide 134, thereby providing additional alignment. Additionally, the pin guide 134 fits wholly within the dowel pins 155 of the belt link assembly 135 to provide support for the dowel pins 155 along the outer periphery 206. The installation of the pin guide 134 is followed by the installation of the washers 143 onto the shafts 122 and 125.
The bearings 193 are pressed into the blind holes 192 in the cover plate 140. The assembled coverplate 140 and bearings 193 are then pressed onto the protruding shafts 122 and 125 and the alignment pins 188. Once pressed into position, the protruding dowel pins 155 of the belt link assembly 135 engage the groove 191 in the cover plate 140. Fasteners 142 are used to restrain the assembly. In this arrangement, as the motor 121 is powered, the gears 136, and ultimately the belt assembly 130 are still able to rotate.
In operation, the linear peristaltic pump may or may not be used with a controller 103. Embodiments without a controller 103 would require manual activation. The motor 121 is powered by an electrical power source (not shown). When the motor 121 is powered, the motor shaft 128 rotates, thereby rotating the driveshaft 122 in the bearing 123. Rotation of the driveshaft 122 forces the drive gear assembly 235 to turn. Rotation of the drive gear assembly 235 forces the belt link assembly 135 to rotate about the drive gear assembly 235. As the belt link assembly 135 rotates, it forces the idler gear assembly 230 to rotate. With the belt link assembly 135 being driven by the drive gear assembly 235, the dowel pins 155 in the belt link assembly 135 are forced to move along the groove 117 in the base 111 and the groove 191 in the cover plate 140. The pin guides 134 are sized such that the dowel pins 155 may ride on the outer periphery 206 of the pin guides 134. This arrangement provides the dowel pins 155 with support when not supported by the endcaps 137 and 138, such as for example when the dowel pins 155 are passing over the flat area between gear assemblies 235 and 230.
The flat area between the drive gear 136 and the idler gear 236 provides the rollers 156 in the belt link assembly 135 with a linear translation on the flat segment of the belt link assembly 135 located adjacent to the linear portion 108 of the traction plate 112. The traction plate 112, having a working position and a loading position, may be hingedly connected to the assembly. In the working position, the traction plate 112 cooperatively works with the rollers 156 of the belt link assembly 135 to maintain a predetermined spacing between the rollers 156 and the linear portion 108 of the traction plate 112. In the loading position, the gap between the traction plate 112 and the rollers 156 may be enlarged slightly to provide the user with the ability to load a product tube 210 into the gap.
Once the product tube 210 is loaded into the gap, the traction plate 112 is moved to the working position, wherein the working position provides for compression to the point of sealing the inner passage of the product tube 210 at the rollers 156. In this embodiment, the depressors are rollers 156 connected to a belt. Two rollers 156 initially compress the product tube 210, one at the upper end 106 of the linear portion 108 and one at the lower end 107 of the linear portion 108. In this arrangement, as the motor 121 is powered, the drive belt assembly 130 begins to move along the grooves 117 and 191. As the belt assembly 130 moves around the grooves 117 and 191, the rollers 156 are forced to follow, thereby compressing the product tube 210 and moving linearly along the product tube 210 and the linear portion 108 of the traction plate 112.
As the rollers 156 roll along the product tube 210, the product tube 210 is compressed by the upper roller 156 throughout the duration of the roll along the product tube 210. Moving the compression point of the product tube 210 along the linear portion 108 of the traction plate 112, illustratively from the upper end 106 to the lower end 107 of the linear portion 108, forces product located in the inner passage of the product tube 210 to be moved along in front of the roller 156. The roller 156 at the lower end 107 of the linear portion disengages from the product tube 210 when the belt assembly 130 begins to rotate. A subsequent roller 156 engages the product tube 210 at the upper end 106 of the linear portion 108, essentially simultaneously with the disengagement of the lower roller 156. This process is repeated with each roller 156 as the motor 121 continues to drive the belt assembly 130. If the motor 121 is stopped, at least one of the rollers 156 is engaged with the product tube 210 to provide a hermetic seal for the contents of the product tube 210 and/or a package 220.
Once properly routed in the working position, the linear peristaltic pump 100 may be primed, step 14, by the operator to ensure that product will flow when the motor is powered. Once primed, the process moves to step 15, wherein the controller 103 is in a wait state. At a predetermined time interval, the controller will check for a dispense signal as shown in step 20. If a dispense signal has not been recorded, the process will return to step 15, wherein the controller 103 will wait for another time interval. If a dispense signal has been recorded in step 20, the process moves to step 25, wherein the driver rotates the belt along the linear portion 108 of the traction plate 112 from the upper end 106 to the lower end 107 of the linear portion 108 of the traction plate 112. In this step, the roller 156 compressing the product tube 210 at the upper end 106 of the linear portion 108 is forced downward along the linear portion 108 and the product tube 210, thereby dispensing product. Once the belt rotates, the roller 156 initially at the lower end 107 of the linear portion 108 begins to move around the drive gear assembly 235 and begins to release from the product tube 210, and eventually fully releases from the product tube 210. As the lower roller 156 releases the product tube 210, the succeeding roller 156 in the belt assembly 135 compresses the product tube 210 at the upper end 106 of the linear portion 108. Therein, at least one roller 156 is compressing the product tube 210 at all times. After the dispense, the process moves to step 30, wherein the controller 103 determines if more repetitions are required. If more repetitions are required, the process moves to step 25, and the process continues for another cycle. If the proper amount of product has been dispensed, no further repetitions will be required, and the process moves to step 35, where the dispense ends. The process then moves to step 15, wherein the controller 103 waits for another dispense signal.
As shown in
In use, the ribbon support 405 is secured to the base 111 to provide a locating point for the anti-drag ribbon 405. Once attached, the anti-drag ribbon 405 may hang between the rollers 156 and the traction plate 112. Upon loading of the product tube 210 into the linear peristaltic pump 400, the anti-drag ribbon 405 lies between the product tube 210 and the drive belt assembly 130, and isolates the product tube 210 from the vertical motion of the rollers 156. In place, the rollers 156 directly contact the anti-drag ribbon 405, and the anti-drag ribbon 405 deflects to apply a horizontal force component to the product tube 210. Further, as the rollers 156 move downward, the anti-drag ribbon 405 remains in the same position, thereby eliminating the possibility of the product tube 210 being dragged downward. Accordingly, the product tube 210 experiences predominantly horizontal force components. All other operations of the linear peristaltic pump 400 are identical in form to the linear peristaltic pump 100, and therefore will not be further discussed.
Although the present invention has been described in terms of the foregoing preferred embodiment, such description has been for exemplary purposes only and, as will be apparent to those of ordinary skill in the art, many alternatives, equivalents, and variations of varying degrees will fall within the scope of the present invention. That scope, accordingly, is not to be limited in any respect by the foregoing detailed description; rather, it is defined only by the claims that follow.
