FILL SYSTEM AND METHOD INCLUDING VISUAL INDICATOR DEVICE FOR EMPTY CONDITION

Abstract

A fill system is configured to supply particulate adhesive such as pellets to an adhesive dispensing system and is configured to provide a visual indication when a supply container approaches an empty condition. The fill system includes the supply container, which has an interior space for holding pellets, and an indicator device that emits a visual indication by actuating a light source communicating with the interior space. As a result, when the level of pellets within the interior space drops to a threshold approaching the empty condition, the light energy emitted by the indicator device is visible outside the supply container. The fill system may then be refilled before the completely empty condition is reached.

Description

FIELD OF THE INVENTION

The present invention generally relates to particulate material filling systems and more particularly, to an adhesive pellet filling system and method used with adhesive dispensing systems.

BACKGROUND

A conventional dispensing system for supplying heated adhesive (i.e., a hot-melt adhesive dispensing system) generally includes a melter having an inlet for receiving adhesive materials in solid or liquid form, a heater grid or cartridge for heating the adhesive materials, an outlet for receiving the heated adhesive, and a pump in communication with the outlet for driving and controlling the dispensation of the heated adhesive through the outlet. One or more hoses may also be connected to the outlet to direct the dispensation of heated adhesive to adhesive dispensing guns or modules located downstream from the melter. Furthermore, conventional dispensing systems generally include a controller (e.g., a processor and a memory) and input controls electrically connected to the controller to provide a user interface with the dispensing system. The controller is in communication with the pump, heater grid or cartridge, and/or other components of the system, such that the controller controls the heating/melting and dispensation of the heated adhesive.

In dispensing systems including a melter supplied with solid material, the solid particulate adhesive material may be provided on demand to the melter in the form of adhesive pellets. These adhesive pellets may be supplied into the melter using various techniques, including hand-filling or automated filling, depending on the specific design of the melter. 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 fill system into the melter, when the melter requires additional material to heat and dispense. In this regard, the controller operatively connected to the melter can receive signals indicating the amount of adhesive material in the melter and then actuate delivery of more pellets from the fill system when the amount of adhesive material in the melter is low. The fill system therefore ensures that the amount of adhesive material within the melter remains at sufficient levels during operation of the dispensing system.

One particular type of fill system is a tote-based pneumatic fill system used to provide adhesive pellets to a melter. The tote-based pneumatic fill system includes a 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. As a result, the fill system typically only has to be refilled with adhesive pellets once a day or once per operational shift, in some circumstances. The lengthy time periods between refilling operations of the supply container can sometimes lead to operators forgetting to check whether the fill system is getting close to empty. In addition, the level of pellets within the supply container drops at a slow pace during normal operation, so it can be difficult to gauge how much material is left in the supply container, and when the supply container will need to be refilled. These problems of detecting the level of pellets within the supply container are particularly exacerbated when the pellet level is only checked by an operator opening a lid at the top of the supply container and looking down into the supply container. If the supply container of the fill system runs out of adhesive material, operation of the dispensing system must be shut down until the supply container can be refilled. This refilling process and the resulting restart process for the dispensing system can cause significant downtime if the empty condition of the supply container is not anticipated and addressed in advance of the supply container reaching the empty condition.

For reasons such as these, an improved fill system would be desirable for use with dispensing systems.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, a fill system configured to supply particulate adhesive to an adhesive dispensing system includes a supply container having an interior space for receiving the particulate adhesive and defined by at least one sidewall and a bottom. The at least one sidewall includes at least a portion defined by translucent or transparent material. The fill system also includes an indicator device for emitting a visual indication when the supply container is approaching an empty condition. The indicator device has at least one light source communicating with the interior space such that light energy is emitted in the interior space so as to be visible through the translucent or transparent material to an operator when the supply container is approaching the empty condition.

In one aspect, the supply container also includes a window defined by the translucent or transparent material at the sidewall. As a result, the light energy emitted by the indicator device is visible through the window at the exterior of the supply container when the supply container is approaching the empty condition. This visual indication is therefore provided without requiring an operator to open the lid of the supply container. The light source may emit light energy throughout the interior space such that a majority of the supply container lights up with internal illumination when the supply container approaches the empty condition.

In another aspect, the light source is mounted at least partially in additional structures located within the interior space. To this end, the additional structures are already present in the interior space and so the addition of the light source provides minimized additional resistance to the flow of particulate adhesive towards the bottom of the interior space. One type of structure already located within the interior space is a venturi pump housing of a pump configured to selectively remove particulate adhesive from the interior space. In these embodiments, the light source is mounted at least partially within the venturi pump housing. It is also possible for the drivers or other electronics associated with the light source to be housed within the pump housing, thereby minimizing more space required by the indicator device.

The light source may be mounted in various locations within or adjacent to the interior space of the supply container. For example, the light source may be mounted on or adjacent to a ramp located at the interior space and configured to direct gravity-driven flow of particulate adhesive towards the bottom of the interior space. The ramp may be painted with a color contrasting to the particulate adhesive or to the light energy emitted by the light source to thereby increase the visibility of the visual indication. Thus, the light source may be coupled to the ramp so as to be located within the interior space, or the light source may be positioned behind a ramp aperture in the ramp so that the light source is not within the interior space yet still emits light energy into the interior space via the ramp aperture. This positioning behind the ramp and outside the interior space may be preferred if it is desired to minimize the impedance to the flow of particulate adhesive within the interior space.

In yet another aspect, the indicator device includes a plurality of light sources that are positioned to emit light energy in different directions within the interior space. Such mounting of a plurality of light sources will ensure that some light energy is transmitted throughout the interior space regardless of whether the piling of particulate adhesive within the supply container takes a different formation during different operational cycles. The plurality of light sources may alternatively be positioned in a series located along an elongate length of the ramp. In these embodiments, the series of light sources will be sequentially uncovered as the supply container approaches the empty condition, thereby increasing the intensity of light energy within the interior space as the supply container approaches the empty condition. The indicator device may include first and second portions of light sources, with the first portion configured to emit a different color or intensity of light energy compared to the second portion. In these embodiments, the first portion of light sources is positioned to be uncovered before the second portion of light sources such that the difference in color or intensity can be used to indicate how close the supply container is to the empty condition.

In still another aspect, the light source emits light energy in a flashing pattern. This flashing pattern causes the light energy to be initially detected as a pulsing light energy through the particulate adhesive when the light source is nearly uncovered, and then later detected as a flashing light energy when the light source is uncovered. The light source may be a rugged light emitting diode that is resistant to high temperatures and other environmental conditions typical at the supply container. The light source may be positioned within the supply container such that the light source is uncovered when the particulate adhesive in the interior space has emptied to a selected fill percentage within the range of about 2% filled to about 25% filled. Even more preferably, the light source may be positioned to be uncovered when the particulate adhesive in the interior space has emptied to a selected fill percentage within the range of about 2% filled to about 10% filled. This amount of fill percentage generally provides adequate time for an operator to notice the visual indication and then refill the supply container before the supply container runs out of particulate adhesive.

In another embodiment according to the invention, a method of supplying particulate adhesive to an adhesive dispensing system includes receiving particulate adhesive within an interior space of a supply container. The method also includes removing particulate adhesive from the interior space of the supply container to supply the particulate adhesive to the adhesive dispensing system. A light source is illuminated such that light energy is emitted by the light source in the interior space when the supply container is approaching an empty condition. The supply container includes a sidewall with at least a portion defined by translucent or transparent material, and the emission of light energy in the interior space is visible through the translucent or transparent material to provide a visual indication detectable by an operator outside the supply container. Therefore, the supply container can be refilled before reaching the empty condition.

These and other objects and advantages of the invention will become more readily apparent during the following detailed description taken in conjunction with the drawings herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this 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.

FIG. 1 is a schematic view of an adhesive dispensing system, including a fill system having a supply container according to one embodiment of the current invention.

FIG. 2 is a perspective view of the fill system of FIG. 1, with a portion of the supply container cut away to show a pump and an indicator device located along a ramp.

FIG. 3 is a front perspective view of the ramp of FIG. 2, specifically showing the portions of the pump and the indicator device located within the supply container.

FIG. 4 is a cross-sectional side view of the fill system of FIG. 2, specifically illustrating components located behind the ramp.

FIG. 5 is a perspective view of a lower portion of the pump of FIG. 3.

FIG. 6 is a cross-sectional view through the pump of FIG. 5 along line 6-6, to illustrate the mounting of one or more LEDs within the pump housing.

FIG. 7 is a perspective view of another embodiment of the lower portion of the pump of FIG. 3, including a series of LEDs positioned along the length of the pump housing.

FIG. 8 is a cross-sectional side view of another embodiment of the fill system with different mounting arrangements for LEDs within the supply container.

FIG. 9 is a schematic cross-sectional side view of the fill system according to the invention including a supply container filled with a high amount of pellets, thereby blocking light energy from being emitted through the pellets as shown.

FIG. 10 is a schematic cross-sectional side view of the fill system of FIG. 9, with the pellet level within the supply container lowered such that a minimum amount of light energy is emitted through the pellets.

FIG. 11 is a schematic cross-sectional side view of the fill system of FIG. 10, with the pellet level within the supply container lowered below the LED such that the light emitted inside the supply container is at a higher intensity than in FIG. 10.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1, an adhesive dispensing system 10 in accordance with one embodiment of the invention includes a fill system 12 that is configured to provide a visual indication when the particulate adhesive within a supply container 14 is approaching an empty condition. More specifically, the fill system 12 is used to provide adhesive pellets to a melter 16 of the adhesive dispensing system 10, and the melter 16 feeds liquefied molten adhesive to an applicator module or nozzle 18 using a liquid pump 20. In this regard, the fill system 12 is operated to continually replenish the supply of adhesive within the melter 16 as the pump 18 removes molten adhesive for dispensing at the applicator module or nozzle 18. The adhesive material may define any form or shape that is convenient for delivering by the fill system 12 and for melting by the adhesive melter 16; however, “pellets” have been chosen for illustrative purposes in the illustrated embodiment. It will be understood that the material moved by the fill system 12 may define other solid or semi-solid particulate forms and may consist of non-adhesive materials in other embodiments consistent with the invention. The supply container 14 of the fill system 12 can hold a significant amount of pellets of adhesive such that the fill system 12 only needs to be refilled or serviced by an operator every few hours, or on another relatively infrequent basis. However, the provision of an indicator device in the form of one or more light emitting diodes (LEDs) 22 causes the emission of light energy in the supply container 14, which can be detected when the supply container 14 approaches an empty condition. The supply container 14 may then be refilled before being completely empty, which enables continuous operation of the adhesive dispensing system 10 without significant downtime, when continuous operation is desirable. Furthermore, this indicator device may also avoid the use of active level sensors that would add more expense to the fill system 12 while also requiring additional maintenance.

With continued reference to FIG. 1, the adhesive dispensing system 10 may also include a controller 24 that is operatively connected to the melter 16 and to the fill system 12. The controller 24 receives signals from a level sensor or some other monitoring device within the melter 16 that correspond to the amount of adhesive within the melter 16. When the amount of adhesive within the melter 16 drops below a certain threshold, the controller 24 sends another signal to the fill system 12 to actuate delivery of an amount of pellets into the melter 16 to refill the melter 16. For example, the fill system 12 may include an outlet port 26 connected to a hose 28 extending between the supply container 14 and the melter 16. The delivery of the pellets through the outlet port 26 and the hose 28 may be produced with pressurized air, as well understood in the filling and dispensing field. However, it will be understood that the pellets in the supply container 14 may be removed in other embodiments using other known methods including mechanical agitators and simple gravity flow. The control process for periodically refilling the melter 16 continues as long as the melter 16 is operating so that the melter 16 (and subsequently, the applicator module or nozzle 18) never runs out of adhesive material. It will be understood that the controller 24 may be incorporated into one or more control systems (not shown) that also actuate the liquid pump 20 and the applicator module or nozzle 18 in accordance with external or pre-programmed control signals, without departing from the embodiments of the invention.

The fill system 12 may be used with various types of adhesive dispensing systems 10. In one example, the melter 16, liquid pump 20, and applicator module or nozzle 18 may include a wall-mounted melt assembly as described in U.S. Patent Application No. 61/703,454 to Clark et al. (entitled “Adhesive Dispensing Device Having Melt Subassembly with Optimized Reservoir and Capacitive Level Sensor”), which is co-owned by the assignee of the current application and the disclosure of which is hereby incorporated by reference herein in its entirety. However, it will be understood that the fill system 12 is designed for use with any type of adhesive dispensing system requiring periodic refilling of material without departing from the scope of the invention. Moreover, the fill system 12 may be modified by including the indicator device with other types of supply containers in other embodiments of the invention.

FIGS. 2 through 6 illustrate one embodiment of the fill system 12 in accordance with the invention. The fill system 12 includes the aforementioned supply container 14, which defines a tote having the appearance similar to that of a wheeled waste container. More specifically, the supply container 14 includes a main container body 32 defined by a plurality of sidewalls 34 and a bottom wall 36. In the illustrated embodiment, the plurality of sidewalls 34 includes four sidewalls 34 that define a rectangular-shaped main container body 32. The main container body 32 is closed at a top end 38 by a removable lid 40 that may be pivotally coupled to one of the sidewalls 34 as shown in FIG. 2. An interior space 42 for holding pellets of adhesive is defined by the sidewalls 34, the bottom wall 36, and the lid 40 of the supply container 14. In order to refill this interior space 42, the lid 40 may be pivoted open so that a new supply of pellets can be delivered manually or automatically through the top end 38. The supply container 14 of this embodiment also includes wheels 44 coupled to the main container body 32 adjacent the bottom wall 36 so that the supply container 14 can be repositioned easily during operation and for refilling. Although it will be appreciated that the specific structure defining the shape of the supply container 14 and the interior space 42 may be varied in other embodiments consistent with the invention, the interior space 42 is always sized to contain a significant amount of adhesive material so that the fill system 12 requires refilling on an infrequent basis.

The supply container 14 shown in FIG. 2 also includes windows 46 located in three of the sidewalls 34. The windows 46 are formed from a transparent or translucent material that enables light energy to be transmitted from the interior space 42 by the indicator device, as described in further detail below. Alternatively, the sidewalls 34 may include at least a portion defined by a transparent or translucent material without the provision of windows in other embodiments. An operator may view a fill level of pellets (not shown in FIG. 2) through the windows 46 during emptying of the supply container 14; however, this process of monitoring the fill level of pellets is similar to opening the lid 40 and looking down into the interior space 42, both of which are relatively inaccurate ways to determine the amount of pellets remaining in the supply container 14. Therefore, as described in further detail below, the LED 22 mounted at the supply container 14 is positioned to emit light energy in the interior space 42 and through the translucent or transparent material of the windows 46 when the supply container 14 approaches an empty condition, thereby drawing attention to the need to refill the supply container 14. It will be appreciated that a different number of windows 46, including no windows 46 at all, may be provided in the sidewalls 34 in other embodiments of the invention.

The supply container 14 also includes a ramp 48 positioned along one of the sidewalls 34. The ramp 48 is configured to support a pump 50 configured to remove pellets from the interior space 42 when pellets need to be delivered to the melter 16. In the embodiment shown in FIGS. 2 and 3, the ramp 48 is inserted into the interior space 42 through a cutout portion of a rear sidewall 34 adjacent the wheels 44 or through the top end 38 and then positioned along the rear sidewall 34 so that the interior space 42 tapers downwardly towards the bottom wall 36. The ramp 48 thereby directs gravity flow of pellets to a relatively small area at the bottom wall 36. The pump 50 includes a pump conduit 52 mounted along the ramp 48 and having an inlet 54 located to adjacent this relatively small area at the bottom wall 36. The pump conduit 52 extends to the outlet port 26, which is located along the rear sidewall 34. Accordingly, the pump 50 draws gravity-fed pellets of adhesive into the inlet 54 from the bottom of the interior space 42 so that the supply container 14 continues to operate until the interior space 42 is substantially emptied of pellets. As will be readily understood, the pump 50 may be replaced with alternative structure for removing adhesive pellets from the interior space 42 in other embodiments, including but not limited to mechanical agitators.

With particular reference to FIGS. 3 and 4, further details of the ramp 48 and pump 50 are shown. To this end, the ramp 48 includes an elongate lower ramp portion 60 and an upper ramp portion 62 extending from a top side of the lower ramp portion 60. The lower ramp portion 60 is angled from the sidewall 34 so as to define the tapering of the interior space 42 towards the bottom wall 36. The upper ramp portion 62 is configured to overlie a portion of the rear sidewall 34 and be connected therewith (such as by a fastener 64 or some other similar connecting device) to retain the ramp 48 in position within the supply container 14. The outlet port 26 extends through the upper ramp portion 62 and is configured to extend through the rear sidewall 34 as well so that the hose 28 can be connected into communication with the pump conduit 52.

The lower ramp portion 60 extends across substantially an entire width of the interior space 42 and thereby divides the interior space 42 from an equipment receptacle 66 located behind the ramp 48. The equipment receptacle 66 is a recessed space located within the footprint of the supply container 14 and provides a convenient space outside the interior space 42 for mounting pump equipment 68 used to generate flow of pellets 70 (shown in phantom in FIG. 4) from the inlet 54 and through the pump conduit 52. The pump equipment 68 may include one or more solenoids 72 for controlling flow of pressurized air into the pump conduit 52 at a venturi pump housing 74 disposed adjacent to the inlet 54 and within the interior space 42. The pump equipment 68 may also include control electronics and other known components typically used with pneumatic fill pumps, and this equipment may be modified in other embodiments without departing from the scope of the current invention.

With reference to FIGS. 5 and 6, the venturi pump housing 74 of the pump 50 is shown in further detail. The venturi pump housing 74 includes a portion of the pump conduit 52 running along an elongate direction of the venturi pump housing 74, the elongate direction being defined from a first end 80 of the housing 74 adjacent to the inlet 54 and a second end 82 of the housing 74 opposite the first end 80. As well understood in venturi-type pumps, additional flow passages (not shown in FIGS. 5 and 6) deliver pressurized air from the solenoids 72 into the pump conduit 52 so as to cause a pressure gradient in the pump conduit 52, the pressure gradient tending to draw pellets 70 into the pump conduit 52 for driving with the pressurized air. In the exemplary embodiment shown, the venturi pump housing 74 also includes a front surface 84 facing away from the ramp 48 when installed, a rear surface 86 abutting the ramp 48 when installed, and a pair of light apertures 88 extending through the housing 74 from the rear surface 86 to the front surface 84. The light apertures 88 are separate and independent from the pump conduit 52 and additional flow passages carrying air through the pump 50. The light apertures 88 are configured to receive the indicator device, which includes LEDs 22 as described briefly above.

As most clearly shown in FIG. 6, the LEDs 22 of the indicator device are mounted at least partially within the light apertures 88 so that the LEDs 22 are substantially flush with or slightly projecting beyond the front surface 84 of the venturi pump housing 74. As a result, the LEDs 22 are mounted or incorporated in structure already present within the interior space 42 of the supply container 14. In addition, the LEDs 22 advantageously do not significantly increase the resistance to flow of pellets 70 towards the bottom wall 36, as caused by gravity. Therefore, the indicator device does not adversely affect the flow of pellets 70 within the interior space 42. In the mounting position shown in FIG. 6, the wiring (not shown) for powering and controlling the LEDs 22 may extend through the remainder of the light aperture 88 and into the equipment receptacle 66 for connection to such a power supply. The LEDs 22 and light apertures 88 are shown to be positioned about halfway between the first and second ends 80, 82, but this positioning may be modified to be closer to one or the other end 80, 82 in other embodiments. It will also be understood that the LEDs 22 may be mounted in other positions in or out of the venturi pump housing 74, including but not limited to being recessed within the light apertures 88, in other embodiments consistent with the invention. Several of these alternatives are described with reference to FIGS. 7 and 8 below.

In the illustrated embodiment, the LEDs 22 are rugged LEDs that are resistant to high temperatures and other environmental conditions normally present within the supply container 14. These rugged LEDs may be similar to those used in taillights or light bars of modern emergency vehicles. Although LEDs 22 are shown in the exemplary embodiment, the indicator device could include other types of light sources, such as incandescent light sources mounted within the light apertures 88, in other embodiments. Furthermore, the light sources could be positioned away from the venturi pump housing 74 and connected to the light apertures 88 via optical cables that transmit emitted light energy into the light apertures 88 from the light sources. Regardless of the type of light chosen for use as the indicator device, additional hardware associated with the light sources may also be positioned at or inside the venturi pump housing 74. For example, in some embodiments the controller 24 and/or any associated hardware operating as a driver for the light sources may also be positioned adjacent to or at least partially within the housing 74. Consequently, the LEDs 22 or other light sources define a minimized profile that does not significantly affect or interfere with the placement and operation of other components of the fill system 12, whether these components are located behind the ramp 48 in the equipment receptacle 66 or within the interior space 42.

In operation, the LEDs 22 of the indicator device emit light energy into the interior space 42 of the supply container 14. This light energy is blocked from transmission into the interior space 42 when the level of pellets 70 in the supply container 14 is high enough to cover the LEDs 22. When the level of pellets 70 drops during use, the LEDs 22 become partially uncovered and then completely uncovered as the level of pellets 70 approaches an empty condition. This uncovering of the LEDs 22 causes the light energy emitted from the LEDs 22 to be emitted throughout the entire interior space 42 to internally illuminate a majority of the supply container 14. In this regard, the light energy becomes a visual indication corresponding to the supply container 14 approaching the empty condition. In other embodiments, the LEDs 22 may be actuated to illuminate only when the level of pellets 70 reaches a threshold that approaches the empty condition. The LEDs 22 in such an arrangement could be located in other positions in the supply container 14, including but not limited to at the lid 40 where dust and adhesive pellets 70 cannot affect the transmission of light energy into the interior space 42. Additionally, the light energy emitted by the LEDs 22 may be routed directly to the window 46 rather than being emitted throughout the entire interior space 42 in some embodiments.

The positioning of the LEDs 22 within the interior space 42 is tailored to provide the initial visual indication at a time when the supply container 14 requires refill, but with sufficient time for an operator to see the visual indication and cause the refill to happen in advance of reaching the completely empty condition. For example, the LEDs 22 may be positioned within the supply container 14 such that the LEDs 22 are uncovered by the pellets 70 when the pellets 70 have emptied to a selected fill percentage within the range of about 2% filled to about 25% filled. More preferably, the pellets 70 will uncover the LEDs 22 at a selected fill percentage within the range of about 2% filled to about 10% filled. This selected fill percentage for uncovering the LEDs 22 should provide the visual indication for a sufficient period of time to cause a refill of the supply container 14 before the supply container 14 becomes completely empty. In addition, an operator can determine immediately from the outside environment whether a supply container 14 requires refill by looking through the windows 46 to see if light energy is being emitted in the interior space 42. As a result, periodic checks on the fill level by opening the lid 40 of the supply container 14 are no longer necessary, and the operator of the adhesive dispensing system 10 can be reasonably assured of preventing the supply container 14 from running out of pellets 70. The melter 16 and other downstream components of the adhesive dispensing system 10 can therefore be operated substantially continuously without lengthy delays caused by refilling the supply container 14.

The visual indication provided by the indicator device can be enhanced or modified in a number of ways. In one example, the LEDs 22 are operated to provide light energy in an intermittent flashing pattern rather than a solid pattern. The flashing light energy will be initially detectable within the interior space 42 as a pulsing light emerging through the pellets 70 when the LEDs 22 are nearly uncovered. This pulsing light will later be detected as a flashing light energy when the LEDs 22 are completely uncovered. In this way, the indicator device can draw more attention to the supply container 14 approaching the empty condition so that the empty condition can be avoided. In another example, the ramp 48 is painted so as to be a color contrasting to one or both of the pellets 70 or the light energy emitted by the LEDs 22. This contrasting color is chosen to be more readily visible through the windows 46. Thus, regardless of whether the light energy is emitted as solid light or as flashing light, the high contrast provided by the color of the ramp 48 will enhance the likelihood that the visual indication will be seen by an operator of the adhesive dispensing system 10. More particularly, the visibility of the visual indication is increased by one or more of these modifications.

With reference to FIG. 7, another alternative for enhancing the visual indication provided by the indicator device is shown. In this embodiment, the venturi pump housing 100 has been modified to include a series of light apertures 102a, 102b, 102c, 102d, 102e located along the elongate length of the housing 100 between the first and second ends 80, 82. In all other respects, the venturi pump housing 100 of this embodiment is identical to the venturi pump housing 74 of the first described embodiment, and the same reference numbers have been used on identical components and surfaces where appropriate without further explanation. By providing LEDs 22 in each of the series of light apertures 102a-e, the intensity of light energy emitted throughout the interior space 42 may be increased multiple times as the supply container 14 approaches the empty condition. The intensity increases as the level of pellets 70 is lowered because the pellets 70 sequentially uncover new pairs of LEDs 22 when approaching the empty condition. To this end, when the level of pellets 70 is approaching the first end 80 of the housing 100 near the inlet 54, the intensity of light energy emitted in the interior space 42 and through the windows 46 is significantly increased compared to when the level of pellets 70 is at the second end 82 of the housing 100. Accordingly, a more critical need for an immediate refill of the supply container 14 draws more attention with a more intense visual indication.

The LEDs 22 shown in FIG. 7 or other embodiments may also be oriented in different directions such that light energy emitted by the LEDs 22 is more likely to spread quickly throughout the entire interior space 42 when the supply container 14 approaches the empty condition. This varied positioning of the LEDs 22 also helps ensure that an uneven pile of pellets 70 within the interior space 42 does not adversely affect the amount of time provided by the visual indication to refill the supply container 14. The LEDs 22 shown in FIG. 7 may also be divided into multiple portions of LEDs 22 defining different intensities or colors of light emitted by the LEDs 22. For example, a first portion of the LEDs 22 in the light apertures 102a, 102b may emit light energy at a first color or intensity, and a second portion of the LEDs 22 in the light apertures 102c, 102d, 102e may emit light energy at a second color or intensity. The second portion of the LEDs 22 is uncovered after the first portion, and the modified color or intensity of light energy emitted by the second portion of the LEDs 22 causes a change in the visual indication provided within the interior space 42 and through the windows 46. To this end, an operator may be able to determine different levels of reaction based on the type of visual indication provided. When only the first color or intensity of light is emitted, the operator will understand that refill is necessary but the empty condition is not imminent. When the second color or intensity of light is emitted, the operator will understand that refill needs to happen promptly because the empty condition is imminent. It will be appreciated that the number of LEDs 22 in each portion may be modified without departing from the scope of the invention.

With reference to FIG. 8, another alternative arrangement for the indicator device is shown. More specifically, FIG. 8 illustrates a similar side view, as shown in FIG. 4 of the first embodiment described above. Alternatively or in addition to providing a LED 22 within a light aperture 88 in the venturi pump housing 74, the indicator device of this embodiment may include a LED 22a coupled to the lower ramp portion 60 of the ramp 48 and/or a LED 22b positioned immediately behind a ramp aperture 110 located in the lower ramp portion 60 of the ramp 48. As with the previous embodiments, the LEDs 22a, 22b are rugged LEDs that are resistant to high temperatures and other environmental conditions normally present within the supply container 14. The LED 22a coupled to the ramp 48 is located within the interior space 42 and within the flow path of the pellets 70 of adhesive, so the LED 22a is designed with a minimized profile to limit the additional resistance to the flow of pellets 70 towards the bottom wall 36 and the inlet 54. The LED 22b positioned behind a ramp aperture 110 in the ramp 48 is located within the equipment receptacle 66 and so is out of the flow path of the pellets 70 in the interior space 42. However, the light energy emitted by the LED 22b is directed through the ramp aperture 110 and into the interior space 42 for use in the same manner as the other LEDs 22, 22a described above. The ramp aperture 110 may include a transparent window blocking communication between the interior space 42 and the equipment receptacle 66, or the ramp aperture 110 may be open in some embodiments. It will be appreciated that one or more of the LEDs 22, 22a, 22b and mounting arrangements described in the various embodiments may be provided individually or in any combination according to the preferences of the end user.

With reference to FIGS. 9 through 11, the generalized method of operation for the fill system 12 is shown. In these Figures, the LED 22 is shown mounted on the ramp 48 which guides the pellets 70 towards the bottom wall 36. No other structure in the interior space 42 or in the equipment receptacle 66 is shown in detail. As shown in FIG. 9, the supply container 14 is filled with a high amount of pellets 70 such that the supply container 14 is not approaching the empty condition. In this state, the level of pellets 70 in the interior space 42 covers up the LED 22 to such an extent that effectively none of the light energy (shown schematically by wave lines 120) escapes through the pellets 70 and into the portion of the interior space 42 where that light energy could be detected through the windows 46. Therefore, no visual indication is provided to refill the supply container 14 in this operational state of the fill system 12.

When the level of pellet fill within the supply container 14 is reduced to an intermediate level as shown in FIG. 10, the pellets 70 may still substantially cover the LED 22. However, the amount of pellets 70 located on top of the LED 22 is reduced to the extent that a small amount of the light energy 120 emitted by the LED 22 escapes through the pellets 70 into the remainder of the interior space 42. For example, in the embodiments where a flashing light energy is emitted by the LED 22, this small amount of light energy 120 may be detected through the windows 46 as a soft pulsing light signal. As will be readily understood, as the level of pellets 70 drops lower, the amount of light energy 120 escaping through the pellets 70 will increase, thereby increasing the intensity of the visual indication corresponding to the supply container 14 approaching the empty condition.

Finally, the level of pellet fill within the supply container 14 will eventually be reduced to the low level shown in FIG. 11. In this operational state, the pellets 70 no longer cover the LED 22. As a result, the light energy 120 is largely transmitted throughout the interior space 42 and through the windows 46 for detection by an operator of the fill system 12. Consequently, the visual indication is provided at a maximum intensity when the level of pellets 70 within the interior space 42 falls below the threshold set by the location of the LED 22. When this visual indication is detected, a refill of the supply container 14 may be performed, which will return the supply container 14 back to the state of FIG. 9, in which no visual indication is visible in the interior space 42 or through the windows 46. As noted above, the threshold at which the visual indication is provided may be modified to fit the needs of the end user (e.g., a more frequently monitored fill system 12 can provide the visual indication at a lower level of fill because the refill will be actuated promptly upon emission of the visual indication).

Consequently, the LEDs 22, 22a, 22b of the indicator devices that are provided in the supply containers 14 according to the invention operate to emit a visual indication when the supply container 14 approaches an empty condition. In this regard, operators of a fill system 12 including the supply container 14 may be notified of an imminent empty condition well enough in advance to allow for refilling of the supply container 14 prior to the interior space 42 becoming completely empty. Thus, system downtime for refilling the supply of material is minimized for a melter 16 and other components of an adhesive dispensing system 10 using the fill system 12. Furthermore, the indicator device is a passive device that operates effectively to provide the visual indication without the need for complex or expensive level sensors in some embodiments. Therefore, the fill system 12 of the current invention includes a reliable mechanism for indicating an imminent empty condition without adding significant complexity or expense to the manufacture and maintenance of the fill system 12. The reduced downtime enabled by use of this fill system 12 makes the fill system 12 beneficial for applications in all filling technologies, whether related to adhesive dispensing or otherwise.

While the present invention has been illustrated by a description of several embodiments, and while such embodiments have been described in considerable detail, there is no intention to restrict, or in any way limit, the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broadest aspects is not limited to the specific details shown and described. The various features disclosed herein may be used in any combination necessary or desired for a particular application. Consequently, departures may be made from the details described herein without departing from the spirit and scope of the claims which follow. What is claimed is:

Claims

1. A fill system configured to supply particulate adhesive to an adhesive dispensing system, comprising:

a supply container including an interior space for receiving the particulate adhesive and defined by at least one sidewall and a bottom, the at least one sidewall including at least a portion defined by translucent or transparent material; and

an indicator device for emitting a visual indication when the supply container is approaching an empty condition, the indicator device including at least one light source communicating with the interior space such that light energy is emitted in the interior space so as to be visible through the translucent or transparent material to an operator when the supply container is approaching the empty condition.

2. The fill system of claim 1, wherein the supply container further includes a window defined by the translucent or transparent material at the sidewall, and the light energy emitted by the light source is visible through the window when the supply container is approaching the empty condition.

3. The fill system of claim 1, wherein the light source emits light energy throughout the interior space such that a majority of the supply container is internally illuminated when the supply container is approaching the empty condition.

4. The fill system of claim 1, wherein the light source is mounted at least partially in additional structures located within the interior space such that the light source provides minimized resistance to gravity-driven flow of particulate adhesive towards the bottom of the interior space.

5. The fill system of claim 4, further comprising:

a pump including a venturi pump housing and configured to selectively remove particulate adhesive from the interior space, the light source being mounted at least partially within the venturi pump housing.

6. The fill system of claim 1, wherein the indicator device includes a plurality of light sources that are positioned to emit light energy in different directions within the interior space.

7. The fill system of claim 1, wherein the light source is a rugged light emitting diode resistant to high temperatures.

8. The fill system of claim 1, wherein the supply container further includes a ramp configured to direct gravity-driven flow of particulate adhesive within the interior space towards the bottom, and the light source is mounted on or adjacent to the ramp such that the light source communicates with the interior space proximate the bottom, the light source being uncovered when the supply container approaches the empty condition.

9. The fill system of claim 8, wherein the ramp is painted with a color contrasting to the particulate adhesive or to the light energy emitted by the light source, thereby further increasing visibility of the visual indication.

10. The fill system of claim 8, wherein the light source is coupled to the ramp so as to be located within the interior space of the supply container.

11. The fill system of claim 8, wherein the ramp includes at least one ramp aperture and the light source is positioned behind the ramp and adjacent to the ramp aperture such that light energy is emitted through the ramp aperture into the interior space.

12. The fill system of claim 8, wherein the indicator device includes a plurality of light sources positioned in a series along an elongate length of the ramp such that the series of light sources is sequentially uncovered as the supply container approaches the empty condition.

13. The fill system of claim 8, wherein the indicator device includes at least a first portion of light sources and a second portion of light sources that emits light energy at a different intensity or color than the first portion, and the second portion of light sources is positioned so that the second portion of light sources is uncovered after the first portion of light sources is uncovered to thereby change the visual indication when the supply container approaches the empty condition.

14. The fill system of claim 8, wherein the light source emits light energy in a flashing pattern so that the light energy emitted in the interior space may be initially detected as a pulsing of light energy through the particulate adhesive when the light source is nearly uncovered, and then detected as a flashing light energy when the light source is uncovered.

15. The fill system of claim 1, wherein the light source is positioned within the supply container such that the light source is uncovered when the particulate adhesive in the interior space has emptied to a selected fill percentage within the range of about 2% filled to about 25% filled.

16. The fill system of claim 1, wherein the fill system is configured to perform a method of supplying particulate adhesive to an adhesive dispensing system, the method comprising:

receiving particulate adhesive within an interior space of the supply container;

removing particulate adhesive from the interior space of the supply container to supply the particulate adhesive to the adhesive dispensing system; and

illuminating the light source such that light energy is emitted by the light source in the interior space so as to be visible through the translucent or transparent material to an operator when the supply container is approaching the empty condition.

17. A method of supplying particulate adhesive to an adhesive dispensing system using a fill system including a supply container having at least one sidewall with at least a portion defined by translucent or transparent material and including an indicator device having a light source, the method comprising:

receiving particulate adhesive within an interior space of the supply container;

removing particulate adhesive from the interior space of the supply container to supply the particulate adhesive to the adhesive dispensing system; and

illuminating the light source such that light energy is emitted by the light source in the interior space so as to be visible through the translucent or transparent material to an operator when the supply container is approaching the empty condition.

18. The method of claim 17, wherein the supply container includes a window defined by the translucent or transparent material, and the method further comprises:

emitting the light energy from the light source through the window when the supply container is approaching the empty condition, thereby providing a visual indication detectable outside the supply container.

19. The method of claim 17, wherein illuminating the light source further comprises:

flashing the light source intermittently such that the light energy emitted in the interior space may be initially detected as a pulsing of light energy through the particulate adhesive when the light source is nearly uncovered, and then detected as a flashing light energy when the light source is uncovered.

20. The method of claim 17, wherein the indicator device includes a plurality of light sources positioned in a series, and the method further comprises:

uncovering the series of light sources in a sequential manner as the particulate adhesive is removed and as the supply container approaches the empty condition.

21. The method of claim 17, wherein the indicator device includes at least a first portion of light sources and a second portion of light sources that emits light energy at a different intensity or color than the first portion, and the method further comprises:

uncovering the first portion of light sources to emit a first light energy in the interior space; and

uncovering the second portion of light sources to emit a second light energy having a different intensity or color that the first light energy in the interior space.

22. The method of claim 17, wherein the indicator device includes a plurality of light sources positioned in different orientations, and the method further comprises:

illuminating the plurality of light sources such that light energy is emitted in different directions throughout the interior space, thereby illuminating a majority of the supply container when the supply container is approaching the empty condition.

23. The method of claim 17, further comprising:

utilizing the fill system of claim 1 to receive particulate adhesive, remove particulate adhesive to supply the adhesive dispensing system, and illuminate the light source when the supply container is approaching an empty condition.