Patent Application
20150083230
The present invention relates generally to hot melt adhesive systems, and more particularly, to systems for temporarily storing and transferring unmelted hot melt adhesive particulate, such as from bulk storage to melters and dispenser units.
Hot melt adhesive systems have many applications in manufacturing and packaging. For example, thermoplastic hot melt adhesives are used for carton sealing, case sealing, tray forming, pallet stabilization, nonwoven applications including diaper manufacturing, and many other applications. Hot melt adhesives often come in the form of various solids or pieces (hereinafter referred to as “particulate(s)”). These hot melt adhesive particulates are melted into a liquid form by a melter, and the liquid hot melt adhesive is ultimately applied to an object such as a work piece, substrate or product by a dispensing device suitable to the application.
A supply of unmelted hot melt adhesive particulate must be maintained and delivered to the melter in order for the melter to produce the liquid hot melt adhesive used by the dispensing device. For example, it is known for a person to employ a scoop or bucket to retrieve hot melt adhesive particulate from a bulk supply, and to deliver those particulate to the melter. Typically, this involves filling a hopper or other container associated with the melter one scoop of hot melt adhesive particulate at a time. This requires the person to handle the hot melt adhesive particulate closely, which may be undesirable because hot melt adhesive dust may be stirred up during handling. In addition, transferring hot melt adhesive particulate in this manner is prone to waste caused by spillage.
To address these concerns with hand filling, the solid particulate adhesive material may be provided on demand by automated filling, depending on the specific design of the melter. Moreover, some melters are designed in such a manner that hand filling is not possible. In some of these systems, the adhesive pellets are designed to be transferred by pressurized air from a pneumatic pump of a fill system into the melter, whenever the melter requires additional material to heat and dispense. In this regard, the fill system ensures that the amount of adhesive material within the melter remains at sufficient levels during operation of the dispensing system. The fill system must be supplied reliably with additional adhesive particulate in order to meet the demands of the melter during operation.
One particular type of fill system is defined by a tote-based pneumatic fill system. The tote-based pneumatic fill system includes a trash can-like wheeled supply container (which may also be referred to as a tote) with an interior space having a size sufficient to hold enough adhesive material for multiple hours of operation of the dispensing system. An adhesive bin defined by the tote may contain adhesive particulate for storage prior to melting in the adhesive melter. A transfer pump, such as a pneumatic pump, connects to the adhesive bin for moving the adhesive particulate via a hose from the adhesive bin to the adhesive melter. Pneumatic pumps generally rely on the suction of gas, such as air, entrained within gaps between individual pieces of adhesive particulate stored within the adhesive bin for moving the adhesive particulate. This gas may also be referred to as “make-up” gas.
Traditionally, the adhesive particulate gravity feeds into a lower portion of the adhesive bin toward an inlet of the transfer pump and submerges a majority of the pump inlet. The transfer pump generates a vacuum at the inlet that withdraws the entrained make-up gas and adhesive particulate therein. In turn, the suction of the entrained make-up gas creates a vacuum within the gaps of the adhesive particulate that withdraws additional gas from a surrounding environment. This additional gas must be drawn through the entire height of adhesive particulate stacked on top of the transfer pump inlet, which can be difficult. Thus, the transfer pumps in conventional tote-based fill systems may become starved for air to produce the vacuum required in order to continue moving adhesive particulate out of the adhesive bin.
Conventional tote-based systems also typically include a vibration generating mechanism that agitates the adhesive in an effort to encourage flow of adhesive particulate towards the pump inlets while also assisting with drawing the addition gas or “make-up” gas through the stacked adhesive particulate. This vibration generating mechanism is mounted on a near-vertical surface along a side of the tote including the pump inlet in conventional systems. Although this positioning of the vibration generating mechanism provides sufficient vibration of the adhesive particulate located in close proximity to the back side of the tote, the vibration energy dissipates and becomes less effective as it moves through the mass of adhesive particulate. Consequently, the effectiveness of vibration to break apart or loosen adhesive that is stuck together (such as by being coalesced) in clumps far away from the vibrating surface is reduced. These clumps of adhesive particulate may pass through this zone of insufficient vibration and may then lead to blockages at the pump inlet.
Furthermore, the pump inlet of conventional tote-based systems is generally positioned above the lowest point in the adhesive bin. As a result of this arrangement, the adhesive particulate below the pump inlet is effectively trapped and the pneumatic pump is incapable of removing it from the adhesive bin. Over time, this adhesive particulate will solidify into a solid mass that could break off into clumps that may lead to blockages at the pump inlet. Because of the difficulty in drawing “make-up” air to the pump inlet as described above, it has been impossible to move the pump inlet downwardly further without exacerbating the problems with the pneumatic pump becoming starved for air flow. In addition, the storage capacity of the adhesive bin cannot reasonably be reduced without requiring refills too frequently for convenience of end users. Thus, the conventional tote-based systems continue to struggle with problems caused by clumping of adhesive particulate and air flow to the pump inlets.
There is a need, therefore, for improvements in hot melt adhesive systems, and specifically, a need for an adhesive storage unit and method for use with a transfer pump that addresses present challenges and characteristics such as those discussed above, particularly tailored for use in transferring adhesive particulate from bulk supply to melter(s).
According to one embodiment, a buffer unit is configured to store and transfer adhesive particulate to at least one adhesive melter. The buffer unit includes a buffer bin defined by a housing including a bottom wall and a sidewall extending from the bottom wall to form an interior space. An agitator plate is positioned within the buffer bin and is supported within the buffer bin so as to be angled from a horizontal orientation. More specifically, the agitator plate has an upper end operatively coupled to the sidewall and a bottom end operatively coupled to the bottom wall. Accordingly, the floating plate divides the interior space into a lower chamber portion and an upper chamber portion which is configured to receive a bulk supply of adhesive particulate. The buffer bin also includes a vibration generating mechanism that is coupled to the agitator plate and is configured to selectively vibrate the agitator plate to produce a relative motion between the agitator plate and the bulk supply of adhesive particulate. This relative motion is configured to generate a flow of fluidized adhesive particulate which moves towards the bottom end of the agitator plate. At least one pump inlet is located proximate to the bottom end of the agitator plate so that each pump inlet is configured to receive the flow of fluidized adhesive particulate moving towards the bottom end. The buffer unit is configured to hold a multiple hour supply of adhesive particulate and reliably deliver it to one or more melters using pneumatic transfer pumps.
In one aspect, the sidewall of the buffer bin includes a front side defining an outlet for the adhesive particulate (e.g., at the pump inlet(s)) and a rear side opposite the front side. Along the rear side, a support bracket is coupled to the sidewall at a position above the bottom wall of the buffer bin. This support bracket engages the upper end of the agitator plate, which enables the agitator plate to be disposed at the angle from the horizontal orientation within the buffer bin. The agitator plate includes a periphery and a resilient/rubber cushion extending around the periphery. The resilient cushion member dampens transmission of vibration from the agitator plate into the housing such that most of the vibration generated by the vibration generating mechanism is transmitted to the adhesive particulate. The resilient cushion also prevents leakage of the adhesive particulate into the lower chamber portion, which is where the vibration generating mechanism is located.
The buffer unit also includes a platform operatively coupled to the bottom wall of the buffer bin and a lift mechanism connecting the platform to the bottom wall. The lift mechanism moves the buffer bin upwardly relative to the platform to selectively engage a mobile bin configured to refill the upper chamber portion with the adhesive particulate. For example, the lift mechanism further includes at least one compression spring that biases the buffer bin to move upwardly away from the platform. An air cylinder is connected to the bottom wall of the buffer bin and the platform, and this air cylinder is actuated to move the buffer bin downwardly towards the platform against the bias of the compression spring(s). Consequently, the buffer bin is mounted so that the mobile bin can be rolled over the buffer unit and then the buffer unit can be actively engaged with the mobile bin during refilling of the buffer unit, the mobile bin and buffer unit defining parts of an adhesive fill system. It will be appreciated that some embodiments of the buffer unit include a level sensor that senses whether the adhesive particulate level within the upper chamber portion falls below a predetermined threshold level for requiring refill of the buffer unit. When the level sensor sends such a refill signal, an operator can retrieve and move a filled mobile bin to the position over the buffer unit to refill the buffer bin, as described above.
In some embodiments, the agitator plate also includes a plurality of pins projecting upwardly into the upper chamber portion and configured to assist with breaking apart clumps of coalesced adhesive particulate during vibration of the adhesive particulate. To this end, the pins transfer the vibrations in the agitator plate up into the bulk supply of adhesive particulate above the agitator plate. The plurality of pins may be provided in multiple aligned rows, with the pins in each row laterally offset from pins in adjacent rows so as to ensure that any clumps in the flow of adhesive particulate moving along the agitator plate are broken up before flowing to the pump inlet.
In another aspect, the buffer unit includes a flow control plate located within the upper chamber portion and dividing the upper chamber portion into a pump inlet chamber located adjacent the bottom end of the floating plate and a primary storage container configured to receive and store the bulk supply of adhesive particulate. The flow control plate is coupled to the sidewall and extends towards the agitator plate at a transverse angle to the angle of the agitator plate, the flow control plate defining a leading end adjustably spaced from the agitator plate to define a gap there between. This gap controls communication of adhesive particulate between the primary storage container and the pump inlet chamber. The flow control plate and the agitator plate collectively define a funnel shape for the primary storage container, the funnel shape feeding to the gap between these elements. The leading end of the flow control plate is provided on a moveable gate portion in one aspect, and this moveable gate portion can include a plurality of slots configured to at least partially receive one of the rows of pins when the pins are provided as described above.
The buffer unit in another aspect includes at least one pneumatic transfer pump coupled to the pump inlet(s). The pneumatic transfer pumps remove the adhesive particulate from the buffer unit and deliver it to the adhesive melter. In order to feed makeup air to these pumps, the buffer bin includes air vents located in the sidewall between the flow control plate and the at least one pneumatic transfer pump. The air vents are located to provide a short flow path for makeup air drawn by the vacuum produced at the pumps, this makeup air not being required to travel through the bulk supply of adhesive particulate in the upper chamber portion to reach the pumps. A divider plate may extend between the flow control plate and the sidewall proximate the air vents to divide the pump inlet chamber into an air channel communicating with the air vents and an adhesive outlet portion communicating with the gap and the pump inlet(s). This divider plate may carry a filter which covers a flow path through the divider plate. Consequently, the filter prevents adhesive particulate form entering and blocking the air channel, while also preventing contamination of adhesive with air drawn though the air channel and the air vents.
According to another embodiment in accordance with the invention, a method of transferring adhesive particulate to an adhesive melter with a buffer unit is provided. The method includes storing a bulk supply of adhesive particulate in an interior space of a buffer bin, the buffer bin including an agitator plate engaging a lower surface of the bulk supply. Vibrations are generated at the agitator plate with a vibration generating mechanism coupled to the agitator plate, which agitates the lower surface of the bulk supply and produces a flow of fluidized adhesive particulate. This flow of adhesive particulate moves downwardly along the agitator plate, which is mounted at a non-horizontal orientation within the buffer bin. The method further includes guiding the flow of adhesive particulate along the agitator plate to at least one pump inlet in the buffer unit. The adhesive particulate is then removed from the buffer bin through the pump inlet with at least one pneumatic transfer pump coupled with the pump inlet. As such, the adhesive particulate is delivered on demand to adhesive melters from the buffer bin.
According to yet another embodiment, a fill system is configured to store and transfer adhesive particulate to an adhesive melter. The fill system includes a storage container configured to contain a bulk supply of adhesive particulate, a separating element, and a drive. The separating element is positioned proximate to a bottom end of the storage container and is configured to engage a surface of the bulk supply. To this end, the separating element moves relative to the at least one surface to cause separation of adhesive particulate from the bulk supply and thereby produce a flow of fluidized adhesive particulate from the storage container. The drive is coupled to at least one of the storage container or the separating element. The drive creates the relative motion between the separating element and the at least one surface of the bulk supply.
These and other objects and advantages of the various embodiments of the invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention.
With reference to
A vibration generating mechanism 26 is coupled to this agitator plate 20 so that vibration is transmitted into the adhesive particulate via a bottom surface of the bulk supply of adhesive particulate held within the buffer unit 10. This application of vibration produces a flow of fluidized adhesive particulate that more reliably moves downwardly along the angled agitator plate 20 to the pump inlets 22. As a result, the entire bulk supply of adhesive particulate can be delivered to the pump inlets 22 and removed from the interior space, thereby avoiding pockets of stationary adhesive that cannot be removed from the storage device (e.g., the buffer unit 10). As described in further detail below, the buffer unit 10 includes additional features that optimize pump performance and reliability by providing a short and easy flow path for makeup air to reach the pumps 24, while also ensuring that any coalesced clumps of adhesive in the bulk supply are broken apart before delivery to the pump inlets 22 that could be clogged with such clumps. Accordingly, the buffer bin 12 of the exemplary embodiment enhances the reliability of supply to an adhesive melter by overcoming problems with pneumatic pump clogging, as well as inefficient pump operation caused by a lack of air available to be drawn through the pneumatic pump 24.
The buffer unit 10 may be used in some adhesive fill systems as an intermediate storage device located proximate the mounting location for one or more adhesive melters and adhesive dispensing devices. To this end, the buffer unit 10 is configured to hold sufficient adhesive particulate to supply the connected adhesive melters for a couple of hours of operation time or longer, which enables a period of time to refill the buffer unit 10 by operators of the adhesive dispensing devices. The buffer unit 10 may be refilled from larger bulk stock of adhesive particulate using mobile bins (described briefly below with reference to
Now with particular reference to
The rear side 36 of the housing 14 is generally solid, although the buffer bin 12 can include one or more viewing windows 46 at the rear side 36 that allow the level or amount of adhesive particulate in the buffer bin 12 to be viewed from outside the buffer bin 12, even when the lid 42 is closed. The viewing windows 46 also allow for an operator to confirm proper operation of the buffer bin 12 so that air starvation or clogging of the pneumatic transfer pumps 24 connected to the buffer bin 12 does not occur. It will be understood that the windows 46 may be omitted or repositioned in other embodiments of the invention.
The front side 34 of the housing includes a series of the pump inlets 22 that project through the housing 14 adjacent the junction of the bottom wall 30 with the front side 34. The pump inlets 22 define an outlet 50 from the interior space IS of the housing 14. In some embodiments such as the one shown in
Also shown in
The buffer unit 10 also includes the agitator plate 20, which is positioned into the housing 14 as briefly described above. The agitator plate 20 is visible in
More particularly, the agitator plate 20 is supported at the upper end 62 thereof by sitting on a ledge provided by a support bracket 64 welded or otherwise coupled to an interior surface 36a of the rear side 36 of the housing 14. The support bracket 64 is provided in a fixed position in the exemplary embodiment shown, but it will be understood that the support bracket 64 may be adjustable in position. To this end, in some embodiments the support bracket 64 is removably coupled to the sidewall 32 such as by bolt fasteners so that the support bracket 64 can be moved upwardly or downwardly to change the plate angle α (however, it will also be understood that the size of the agitator plate 20 itself would likely need to be modified as well if the position change of the support bracket 64 was significant because the agitator plate 20 must still prevent adhesive particulate from flowing into the lower chamber portion 18). The support bracket 64 functions advantageously to prevent the agitator plate 20 from wedging into significant frictional engagement around its entire periphery 68 with the housing 14, as such wedging would cause more transmission of vibrations into the sidewall 32 (e.g., the ability of the agitator plate 20 to vibrate by itself would be significantly reduced) and significant difficulty in removing the agitator plate 20 when necessary, both of which are undesirable. As a result of the rigid support by the bottom wall 30 at the bottom end 60 and by the support bracket 64 at the upper end 62, the agitator plate 20 is maintained in position during loading of the buffer bin 12 with adhesive particulate and during use of the buffer bin 12.
The buffer unit 10 also includes the vibration generating mechanism 26 mounted to the agitator plate 20 along a bottom side 20a thereof. To this end, the vibration generating mechanism 26 is coupled with the agitator plate 20 using fasteners 66 so as to project downwardly into the lower chamber portion 18, as most clearly shown in
The agitator plate 20 also includes additional mounting features that enhance the transmission of vibration from the vibration generating mechanism 26 into the adhesive particulate. More specifically, the agitator plate 20 defines a periphery 68 and a resilient cushion 70 is positioned around the periphery 68. The resilient cushion 70 is formed from rubber in the exemplary embodiment, but other similar materials may be used for the similar functionality described below. This rubber cushion 70 serves multiple functions. First, the rubber cushion 70 effectively seals the joint formed between the agitator plate 20 and the remainder of the housing 14 so that the adhesive particulate cannot escape through to the lower chamber portion 18. Second, the rubber cushion 70 tends to discourage transmission of the vibration at the agitator plate 20 to the remainder of the housing 14 (e.g., sidewall 32), which forces the vibration to be transmitted primarily to the adhesive particulate instead. In this regard, the rubber cushion 70 is dampening the vibrations before transmissions to the sidewall 32. The agitator plate 20 may also include resilient mounting elements such as springs (not shown in
The agitator plate 20 also includes a plurality of pins 72 extending upwardly from the sloped surface into the upper chamber portion 16. The plurality of pins 72 includes three rows of pins 72 that are aligned with one another in the rows as shown in
The plurality of pins 72 also function to transmit vibration from the agitator plate 20 farther into the bulk supply of adhesive particulate to encourage clumps of coalesced adhesive particulate to break apart before moving to the pump inlets 22. As a result of the vibration being applied along a substantial portion of the bottom surface defined by the upper chamber portion 16 and the pins 72 breaking flow of the adhesive particulate apart, clumps of adhesive do not tend to pass into the pump inlets 22 and therefore clogging of the pump inlets 22 with clumps of coalesced adhesive particulate is minimized. It will be understood that the relative lengths of the pins and the arrangement of those pins in rows may be modified in other embodiments of the buffer bin 12 without departing from the scope of the invention.
With continued reference to
The flow control plate 78 is angled in an opposite or transverse orientation to the sloped surface defined by the agitator plate 20. As a result, the flow control plate 78 extends towards the agitator plate 20 and defines a gap 82 or opening between a leading end 84 of the flow control plate 78 and the agitator plate 20. The gap 82 is sized to control the communication of fluidized adhesive particulate moving towards the pump inlets 22. As described in further detail below, the flow control plate 78 also includes an adjustable gate portion 86 that is moveably coupled to the remainder of the flow control plate 78 and that defines the leading end 84 of the flow control plate 78. The adjustable gate portion 86 extends from the tip of the air channel housing 76 (e.g., at the junction of the divider plate 80 and the flow control plate 78) to modify or reduce the size of the gap 82 defined between the agitator plate 20 and the flow control plate 78. It will be understood that the gate portion 86 is configured such that the maximum size of the gap 82 still prevents any remaining non-fluidized clumps of adhesive particulate which are too large to fit in the pump inlets 22 from moving to the pump inlets 22
Consequently, the flow control plate 78 including the gate portion 86 effectively subdivide the upper chamber portion 16 of the buffer bin 12 into two additional portions: a pump inlet chamber 90 located adjacent to the pump inlets 22 and the bottom end 60 of the agitator plate 20, and a primary storage container 92 located above the flow control plate 78 and above the agitator plate 20, particularly at locations near the upper end 62 of the agitator plate 20. The primary storage container 92 is configured to hold the bulk supply of adhesive particulate within the buffer bin 12 and the flow control plate 78 and agitator plate 20 collectively define a funnel shape at the bottom of this primary storage container 92. The funnel shape leads to the gap 82 between the leading end 84 of the flow control plate 78 and the agitator plate 20, so the primary storage container funnels or leads the adhesive particulate towards the gap 82 for metered flow into the pump inlet chamber 90. The divider plate 80 extends across the pump inlet chamber 90 as shown in
The gate portion 86 is coupled to the remainder of the flow control plate 78 in such a manner so as to be adjustable in position by an operator of the buffer unit 10. To this end, the gate portion 86 of the exemplary embodiment includes linear slots 96 each configured to receive a fastener 98 that extends through the gate portion 86 and through the flow control plate 78. When the fastener 98 is loosened (such as by manual adjustment), the gate portion 86 is free to slide upwardly and downwardly along the remainder of the flow control plate 78 (e.g., the fasteners 98 can move in the linear slots 96). This movement of the gate portion 86 modifies the thickness of the gap 82 between the leading end 84 defined by the gate portion 86 and the agitator plate 20. Accordingly, the specific size of gap 82 provided between the primary storage container 92 and the pump inlet chamber 90 may be adjusted depending on the particular application by moving the gate portion 86 and re-tightening the associated fasteners 98. Of course, it will be appreciated that the gate portion 86 may be automatically adjustable in position in other similar embodiments rather than manually adjusted in position.
In operation, round pellet shaped adhesive particulate and smaller sizes of adhesive particulate tend to roll and slide more readily down the agitator plate 20, so the gap 82 may be made smaller to prevent this more free-flowing adhesive particulate from completely filling/flooding the pump inlet chamber 90. Likewise, when chicklet-shaped or irregular-shaped adhesive particulate or larger sized adhesive particulate is used in the buffer bin 12, the gate portion 86 may be moved upwardly to form a larger gap 82 to ensure sufficient flow of the less free-flowing adhesive particulate enters the pump inlet chamber 90. Operators may test and adjust the size of the gap 82 for different types of adhesive particulate, in order to find the preferable balance between flow into the pump inlet chamber 90 and maintaining an air pocket above the particulate adhesive in the pump inlet chamber 90 (e.g., not completely flooding the pump inlets 22). The gap 82 is therefore adjustable to reliably meter many different types of solid adhesive particulate that may be used with the buffer unit 10 and the associated adhesive fill system.
As shown most clearly in
The divider plate 80 of the air channel housing 76 is configured to include a plurality of filter screens 102 that enable flow of air through the air vents 54 and the air channel 56 to pass into the air pocket formed at the top of the pump inlet chamber 90. The filter screens 102 also prevent contamination such as dust from entering the interior space IS and affecting the adhesive particulate being delivered by the pneumatic pumps 24 connected to the pump inlets 22. In addition, the filter screens 102 also provide a positive block to adhesive particulate that may partially fill the pump inlet chamber 90 at times. The adhesive particulate in the pump inlet chamber 90 therefore cannot move into the air channel 56, which avoids any blockage of the air space in the air channel 56 located proximate to the pump inlets 22. Accordingly, even if an air pocket within the pump inlet chamber 90 (which is desirable to maintain, if possible) fills with adhesive particulate in a temporary flooding of this compartment, the pump inlets 22 will still be able to form vacuum by drawing makeup gas from the air channel 56 without requiring this makeup gas to be drawn through the entire bulk supply located in the primary storage container 92. However, these circumstances should be noted through the windows 46 of the sidewall 32 if they occur frequently, and the size of the gap 82 adjusted with the gate portion 86 to further meter or limit flow of adhesive particulate and allow for the desirable air pocket to be even closer to the pump inlets 22 during normal operation. Regardless, the air channel 56 and the divider plate 80 with filter screens 102 ensures reliable operation of the pneumatic pumps 24 because the path for makeup gas is short and not subject to significant constriction.
As schematically shown in
During operation of the adhesive melters (not shown) fed by the pneumatic pumps 24 at the pump inlets 22, the buffer unit 10 provides several advantages compared to the conventional tote-based systems. The vibration applied along an entire sloped surface of the agitator plate 20 ensures that the adhesive particulate about to move into the pump inlet chamber 90 is vibrated and forced through and around the plurality of pins 72 to break up any clumps of coalesced adhesive particulate. Furthermore, the vibration helps efficiently move a desired amount of adhesive particulate to the pump inlets 22 on demand from the pneumatic pumps 24. The adjustment of the gap 82 between the primary storage container 92 and the pump inlet chamber 90 enables a metered amount of flow into the pump inlet chamber 90 regardless of the size and shape of adhesive particulate being used at the buffer bin 12. Furthermore, makeup gas or air for operation of the pumps 24 is provided in the air channel 56 as well as in an air pocket formed above the adhesive particulate within the pump inlet chamber 90, each of these being proximate to the pump inlets 22. This air is therefore readily drawn into the pump inlets 22 by the pneumatic pumps 24 during operation, thereby ensuring an efficient and reliable operation of the pneumatic pumps 24. The air flow is shown by arrows 106 in
The buffer unit 10 may include additional elements for advantageous use with other components of an adhesive fill system. For example, the buffer unit 10 includes a platform 110 for selectively lifting the buffer bin 12 as shown in
As shown in
In the exemplary embodiment shown, the lift mechanism 114 includes at least one compression spring 124 biasing the buffer bin 12 upwardly away from the platform 110 towards a raised position (
More particularly, the buffer bin 12 may be used in continuous operation while the mobile bin 112 is placed in contact with the buffer bin 12 in some embodiments. In this regard, the buffer bin 12 may be continuously replenished with adhesive particulate from the mobile bin 112 during operation. In such embodiments, the level sensor 104 may be located near the top opening 40 for detecting when the mobile bin 112 has run out of adhesive particulate and is no longer replenishing the supply in the buffer bin 12. When this occurs, the buffer bin 12 is configured to supply adhesive particulate to multiple adhesive melters for at least a couple of hours (e.g., the buffer bin 12 contains at least 15-20 kilograms of adhesive particulate, in one example) before running out. This time period allows the operator to remove the mobile bin 112 and refill it for replacement at the buffer bin 12 at the earliest convenience.
Alternatively, the buffer bin 12 may be filled by the mobile bin 112 and then the mobile bin 112 removed for filling other buffer bins 12. In such embodiments, the lid 42 of the buffer unit 10 is closed during operation and the level sensor 104 is typically moved to a lower location within the upper chamber portion 16, as alluded to above. The level sensor 104 would still provide warning with enough lead time to enable a refilling of the upper chamber portion 16 with adhesive particulate, but the time window would be shortened from the previously described operation. Regardless of the particular operation, the buffer unit 10 provides intermediate bulk storage and metering of adhesive particulate to pneumatic pumps 24 and to adhesive melters as needed during operation of a hot melt adhesive dispensing system. Furthermore, the buffer unit 10 improves the operation and efficiency of storage and fill systems used with a hot melt dispensing system.
While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.
This application claims the priority of U.S. Provisional Patent Application Ser. No. 61/880,534, filed on Sep. 20, 2013 (pending), the entire disclosure of which is hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61880534 | Sep 2013 | US |
