System and method for monitoring liquid adhesive flow - Patents.com

Abstract

To solve such a problem that a measuring system used together with the discharge unit of a hot melt adhesive is needed.SOLUTION: A flow meter used in a hot melt adhesive system comprises a housing body having a hollow central recess, an inflow passage composed to receive the hot melt adhesive from a manifold and an outflow passage composed to return the hot melt adhesive to the manifold for discharge. The flow meter also comprises a housing cover which is removably installed to the housing body and has a flat inner face adjacent to the hollow central recess of the housing body. Further, the flow meter comprises a pair of rotatable gears provided in the hollow central recess and fixed rotatably between the housing body and housing cover, and at least one sensor composed to measure the amount of the hot melt adhesive flowing through the flow meter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 318,114, filed April 4, 2016, the disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates generally to hot melt adhesive systems, and more particularly to an adhesive tracking system configured to monitor the amount of hot melt adhesive or other flowable liquid material dispensed from a hot melt adhesive system. [Background technology]

[0003] Dispensing systems that dispense thermoplastic hot melt adhesives or other flowable materials are widely used in the manufacturing and packaging industries. For example, hot melt adhesives may be used in carton sealing, case sealing, tray forming, pallet stabilization, and nonwoven applications, among others. Typically, the hot melt adhesive is contained in and provided from an adhesive supply, such as a tank or hopper of an adhesive melter. In response, the hot melt adhesive is heated, melted, and pumped to a dispenser, such as a dispensing applicator or other applicator, which applies the hot melt adhesive to a product or substrate.

[0004] Typically, a manifold is used to direct the liquid hot melt adhesive into multiple flow streams and output through hoses to a dispenser. Different types of pumps, such as piston pumps, drive the liquid hot melt adhesive through a hot melt adhesive system that includes a manifold. A metering system can monitor the flow of hot melt adhesive in a hot melt adhesive dispensing system. Conventional metering systems are typically in fluid communication with each respective outlet of the dispensing system such that the flow of liquid material through each outlet can be individually monitored. This configuration is suitable for low discharge flow rates and ensures that a restriction in flow through one liquid outlet does not affect the flow of liquid from the remaining liquid outlets.

[0005] However, the cost of installing an individual flow meter for each liquid outlet is economically impractical, especially for a dispensing system that may have four to six applicators. Moreover, multiple flow meters require more maintenance costs due to the number of components. Furthermore, conventional metering systems cannot be retrofitted to existing dispensing systems. Summary of the Invention [Problem to be solved by the invention]

[0006] Thus, there is a need for a metering system for use with hot melt adhesive dispensing units that addresses these shortcomings, for example, by providing a single flow meter in direct fluid communication with the hot melt adhesive system manifold that monitors the amount of adhesive dispensed on every product. [Means for solving the problem]

[0007] In one embodiment, an adhesive tracking system is disclosed for monitoring the output of a hot melt adhesive. The adhesive tracking system includes a flow meter having an inlet and an outlet. The flow meter is configured to measure an amount of adhesive flowing out of the outlet. The adhesive tracking system further includes a manifold configured to output the adhesive. The manifold is in fluid communication with the flow meter. The adhesive tracking system also includes at least one product detector configured to detect the presence of a product to which the adhesive is to be applied, and a controller in communication with the flow meter and the at least one product detector. The controller includes a processor configured to determine a start time and an end time of application of the adhesive to the product, receive an amount of adhesive flowing out of the flow meter outlet from the start time to the end time, and associate the amount of adhesive with the product.

[0008] In another embodiment, a method for monitoring hot melt adhesive flow is disclosed that includes detecting the presence of a product to which adhesive is to be applied using at least one product detector, determining a start time and an end time for applying adhesive to the product, determining an amount of adhesive applied to the product from the start time to the end time by measuring an amount of adhesive dispensed from a manifold using a flow meter in fluid communication with the manifold, and relating the amount of adhesive to the product.

[0009] In another embodiment, a flow meter is disclosed for use in a hot melt adhesive system including an adhesive supply, a manifold, a heater, and at least one hose connected to a dispensing applicator. The flow meter includes a housing body having a hollow central recess, an inlet passage configured to receive hot melt adhesive from the manifold, and an outlet passage configured to discharge hot melt adhesive back to the manifold. The flow meter also includes a housing cover removably attached to the housing body and having a flat inner surface adjacent the hollow central recess of the housing body. The flow meter further includes a pair of rotatable gears disposed within the hollow central recess and rotatably fixed between the housing body and the housing cover, and at least one sensor configured to measure an amount of hot melt adhesive flowing through the flow meter.

[0010] In another embodiment, a hot melt adhesive system includes an adhesive supply holding a solid or semi-solid hot melt adhesive, a heater associated with the adhesive supply for melting the solid or semi-solid hot melt adhesive into a liquid hot melt adhesive, a first manifold in fluid communication with the adhesive supply, a pump for pumping the liquid hot melt adhesive from the heater to the first manifold, an air pressure regulator for regulating the flow of air from an air supply to the pump, at least one adhesive applicator configured to apply the liquid hot melt adhesive to a substrate, and an adhesive tracking system for monitoring the output of the liquid hot melt adhesive. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a hot melt adhesive system. [Figure 2A] FIG. 2 is a rear perspective view of the dispensing unit and adhesive tracking system of the hot melt adhesive system of FIG. [Figure 2B] FIG. 2 is a rear perspective view of a dispensing unit of the hot melt adhesive system and a flow meter of the adhesive tracking system of FIG. [Diagram 3]FIG. 1 is a schematic diagram of an adhesive tracking system. [Figure 4] FIG. 2 is a top perspective view of the flow meter. [Diagram 5] FIG. 2 is a top exploded perspective view of the flow meter. [Figure 6] FIG. 2 is a perspective view of the bottom of the flow meter. [Figure 7] FIG. 2 is a partially exploded bottom perspective view of the flow meter. [Figure 8] FIG. 2 is a plan view of the bottom of the housing cover of the flow meter. [Figure 9] 9 is a cross-sectional view of the housing cover taken along line 9-9 of FIG. 8. [Figure 10A] FIG. 13 is a rear perspective view of an embodiment of an adhesive tracking system with an auxiliary manifold attached directly to a dispensing unit. [Figure 10B] FIG. 2 is a rear perspective view of an embodiment of an adhesive tracking system with an auxiliary manifold mounted remotely to the dispensing unit. [Figure 11A] FIG. 2 is a perspective view of an auxiliary manifold. [Figure 11B] FIG. 11B is a perspective view of a flow meter connected to the auxiliary manifold of FIG. [Figure 12A] FIG. 2 is a front view of an air pressure regulator according to the present disclosure. [Figure 12B] FIG. 12B is a side view of the air pressure regulator of FIG. 12A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] As shown in FIG. 1, the hot melt adhesive system 10 includes a dispensing unit 20 including an adhesive supply 22 for containing and melting a solid or semi-solid hot melt adhesive 24a, such as pellets, a manifold 26 connected to the adhesive supply 22, a controller 28, and a user interface 29. The adhesive supply 22 may be, among other things, a tank melter or a grid and reservoir melter. Upon melting, the solid or semi-solid hot melt adhesive 24a stored in the adhesive supply 22 is transformed into a liquid hot melt adhesive 24. The adhesive supply 22 includes a sidewall 30, a removable cover 31, and a base 32 with one or more adhesive supply heaters 34 for melting and heating the hot melt adhesive 24a and the liquid hot melt adhesive 24 in the adhesive supply 22. An adhesive supply outlet 36 adjacent the base 32 couples to a passageway 38 that connects to an inlet 40 of the manifold 26.

[0013] The manifold 26 can be integrated directly into the dispensing unit 20 of the hot melt adhesive system 10, with the manifold 26 attached to a sidewall 30 of the adhesive supply 22. A dispensing unit 20 with such an integral manifold 26 is shown in Figures 2A and 2B. As will be described in more detail below, in other embodiments, the auxiliary manifold can be retrofitted to other hot melt adhesive systems by attaching it directly or indirectly to the dispensing unit 20.

[0014] Referring again to FIG. 1, a positive-displacement pump 58, such as a vertical piston pump (as shown) or a gear pump, is coupled to the manifold 26 for pumping the liquid hot melt adhesive 24 from the adhesive supply 22 to the manifold 26 where it is split into separate streams. A pump motor 59 drives the pump 58. The manifold 26 is attached to a side wall 30 of the adhesive supply 22 by a spacer 41 and is spaced from the adhesive supply 22 by a distance 42 sufficient to provide thermal insulation of the adhesive supply 22 from the manifold 26. The manifold 26 has a number of outlet ports 44 that can receive heated hoses 46 that are attached to one or more adhesive applicators 48, 50 for supplying the liquid adhesive 24 to the applicators 48, 50. Although FIG. 1 shows the adhesive supply 22 in physical proximity to the manifold 26, other configurations are possible where the source of hot melt adhesive is physically separate from the manifold. In such an arrangement, two or more pumps may be used to move the hot melt adhesive from the adhesive supply 22 towards the final application point.

[0015] As shown diagrammatically in FIG. 3, the manifold 26 can generate multiple flow streams that are conveyed by corresponding heated hoses 46 to the applicators 48, 50. The applicators 48, 50 include one or more adhesive dispensing modules 54 configured to dispense / apply the liquid hot melt adhesive 24 to a product, such as a carton, package, or other object. The adhesive dispensing modules 54 are attached to an applicator body 51 that includes an applicator heater 53 and is supported by a frame 52. Although the hot melt adhesive system 10 includes two applicators 48, 50, one on each side of the dispensing unit 20, as shown in FIG. 1, other embodiments of the adhesive system 10 can use different numbers of applicators, dispensing modules, and other configurations.

[0016] Also, as shown in FIG. 1, the manifold 26 is located adjacent to the adhesive supply 22 between the adhesive supply 22 and the controller 28. It will be appreciated that other configurations in which the manifold 26 is located in the center of the unit 20 may be used. The outlet ports 44 of the manifold 26 are located substantially in the center of the dispensing unit 20 such that the distance from a given outlet port 44 to the tank side or the controller side of the unit 20 is substantially the same. This centralized location of the outlet ports 44 allows the same length of hose 46 to be used to supply the liquid adhesive 24 to the dispensing applicators 48, 50 located on either side of the dispensing unit 20. The manifold 26 may include a manifold heater 56 that is separate from the adhesive supply heater 34 and may be independently controlled by the controller 28. It will be appreciated that a single heater may be used to heat the adhesive supply 22 and the manifold 26.

[0017] The dispensing unit 20 includes a controller 28 that houses the power supply and electronic controls for the dispensing unit 20. The hoses 46 are electrically coupled to the controller 28 by cord sets 62 associated with each hose 46. The controller 28 individually monitors and regulates the adhesive supply heaters 34, manifold heater 56, hoses 46, and applicator heaters 53 to melt the solid or semi-solid adhesive 24a contained within the adhesive supply 22 and maintain the temperature of the liquid adhesive 24 to ensure the proper viscosity of the adhesive 24 delivered to the applicators 48, 50 and dispensed by the adhesive dispensing module 54.

[0018] With respect to the heating mechanism of the hot melt adhesive system 10, the controller 28 is electrically coupled to the heaters, including the adhesive supply heater 34, the manifold heater 56, and the applicator heater 53, as well as any hose heaters. The controller 28 may also be coupled to various temperature sensors within the hot melt adhesive system 10, which may be associated with or included in the adhesive supply heater 34, the manifold heater 56, the applicator heater 53, and any hose heaters. The controller 28 individually monitors and regulates the adhesive supply heater 34, the manifold heater 56, the applicator heater 53, and any hose heaters to melt the solid or semi-solid hot melt adhesive 24a contained within the adhesive supply 22 and maintain the temperature of the (molten) liquid hot melt adhesive 24 to ensure the proper viscosity of the liquid hot melt adhesive 24 supplied to the applicators 48, 50 and dispensed by the adhesive dispensing module 54. For example, the controller 28 receives temperature information from the temperature sensors and sends heater control commands to each heater to regulate the temperature. Such heater control commands may increase or decrease the temperature of any or all of the heaters in the hot melt adhesive system 10 .

[0019] The pump 58 is located external to the adhesive supply 22 and is connected to an air pressure regulator 70 that receives air from an air supply 61. More specifically, the air pressure regulator 70 is attached to the dispensing unit 20 and connected to the air supply 61. In some embodiments, the pump 58 can be attached to the manifold 26 and heated by the manifold heater 56. This configuration allows for a larger tank opening 60, increasing tank capacity and reducing the time required to heat the pump 58. Additionally, a flow meter 80 can be attached to the manifold 26. The flow meter 80 includes a pair of sensors that are electrically coupled to the controller 28 by respective cords 63a, 63b associated with each sensor. At least one product detector 90, such as a light sensor, is also electrically coupled to the controller 28.

[0020] The manifold 26, flow meter 80, product detector 90, controller 28, and user interface 29 are components of an adhesive tracking system 37 that monitors the adhesive applied to a product or substrate, including the total amount of adhesive dispensed and the average amount of adhesive dispensed per product, during operation to provide useful system data and alarms to the user. Referring again to FIG. 3, further features related to the adhesive tracking system 37 and its control are disclosed. The pump 58 advances the liquid hot melt adhesive 24 from the adhesive supply 22 to the manifold 26 where the liquid hot melt adhesive 24 is split into multiple flow streams. The manifold 26 includes a flow meter 80 that measures the flow rate of the liquid hot melt adhesive 24 passing therethrough. In other embodiments, the flow meter 80 can be attached to the end of the hose 46. The flow meter 80 collects flow information using at least one flow sensor 88 in electrical communication with the controller 28 and user interface 29 to provide feedback to the user. In some embodiments, a pair of flow sensors 88a, 88b are provided that provide quadrature (orthogonal) outputs. The reason for this is that during a piston pump stroke, material actually flows backwards as well, and the quadrature output allows this backward flow to be subtracted from the forward flow in order to maintain a high level of accuracy. In embodiments using gear pumps which have no backward flow, a single sensor is sufficient.

[0021] The user interface 29 interfaces with the controller 28 to provide the user with information regarding the heating functions of the hot melt adhesive system 10. For example, the user interface 29 presents information regarding adhesive temperature, heater temperature, etc. The user interface 29 also includes controls for adjusting parameters related to the heating of the hot melt adhesive system 10. Additionally, the user interface 29 and controller 28 also provide the user with information regarding the adhesive tracking system 37, as will be described in more detail below.

[0022] 2A and 2B, the hot melt adhesive system dispensing unit 20 is shown and includes a manifold 26, a controller 28, and a user interface 29. In FIG. 2A, the manifold 26 is shown with an insulating jacket 26a that protects the user from burns when the manifold is heated. In FIG. 2B, the manifold 26 is shown without the cover 26a, revealing a flow meter 80 in fluid communication with the manifold 26.

[0023] The adhesive tracking system 37 employs a flow meter 80 that directly measures the output of adhesive. In some embodiments, the flow meter 80 can be removably connected to the manifold 26. With reference to FIGS. 4-7, for example, the flow meter 80 comprises a housing body 82 having an inlet passage 84 configured to receive hot melt adhesive from the manifold 26 and an outlet passage 85 configured to discharge the hot melt adhesive back to the manifold 26. The housing body 82 of the flow meter 80 can be removably connected to the manifold 26 via fasteners 87a, such as screws or bolts. The flow meter 80 further comprises a housing cover 83 that is removably connected to the housing body 82 by a plurality of fasteners 87b, such as screws or bolts. In another embodiment, the flow meter 80 can be integrated into the manifold 26. For example, the housing body 82 can be integrated into the manifold 26 such that the housing cover 83 can be removably connected to the manifold 26 via fasteners 87b. In another embodiment, the individual components of flowmeter 80, such as gears 86, pins 81, and bushings 81a, described in detail below, can be incorporated into housing cover 83 such that housing cover 83 can be directly and removably connected to manifold 26 via fasteners 87b, such that housing body 82 is not used. In yet another embodiment, the individual components of flowmeter 80, such as gears 86, pins 81, and bushings 81a, can be integrated directly into manifold 26 such that housing cover 83 can be directly and removably connected.

[0024] The flow meter 80 further comprises a pair of rotatable gears 86 and at least one sensor 88, such as a magnetic pickup sensor, configured to measure the amount of liquid adhesive flowing through the flow meter. In the illustrated embodiment of the flow meter 80, a pair of sensors 88a, 88b is shown. In particular, the pair of sensors 88a, 88b is configured to measure the rotation of the rotatable drive gear 86 to determine the amount of adhesive flowing out of the outlet 85. The outlet 85 is in fluid communication with the manifold 26 such that the liquid adhesive is returned to the manifold 26 for distribution to the various hoses 46 that are directly connected to the manifold 26. In some embodiments, the outlet 85 can be directly connected to a hose that is connected to an adhesive applicator.

[0025] The housing body 82 also includes an elastomeric seal 89, such as an elongated or oval shaped O-ring, to maintain a watertight seal with the cover to prevent leakage of fluid from the flow meter. Additionally, a number of fasteners 87a, 87b are also adapted to removably secure the flow meter 80 to the manifold 26. In other embodiments, the flow meter 80 can be connected in fluid communication with the pump 58 or any of the hoses 46.

[0026] The gears 86 are received within a hollow central recess 82a of the housing body 82 so as to rotate freely about an axis of rotation. In particular, the gears are rotatably fixed between the housing body 82 and the housing cover 83. In one embodiment, the gears 86 are a series of substantially linearly intermeshing flow metering spur gears each configured to rotate about a respective pin 81 provided in a corresponding bushing 81a in the housing body 82. The spur gears 86 are positioned such that they are substantially coplanar and each spur gear is parallel to and spaced apart from at least one neighboring spur gear. Additionally, the spur gears 86 are positioned such that the axes of rotation of each of the gears are positioned along a common centerline. Additionally, the spur gears 86 are positioned such that the teeth of each spur gear mesh with the teeth of a neighboring spur gear.

[0027] The inlet passage 84 provides a conduit between the liquid source of the manifold 26 and the inlet side of the meshing pair of gears 86. Similarly, the outlet passage 85 provides a conduit between the discharge side of the meshing pair of gears 86 and the manifold 26. The gears 86 are in fluid communication with the inlet passage 84 which directs a pressurized stream of liquid into the recess 82a and toward the inlet side of the meshing pair of gears. As a result, the pressurized liquid stream drives the cooperating gears 86, thereby rotating each of the gears in opposite directions relative to one another. For example, one of the gears rotates in a counterclockwise direction while its immediate neighbor rotates in a clockwise direction. The use of counter-rotating gears 86 provides a positive displacement for accurate metering of liquid hot melt adhesive.

[0028] As a result of this rotation of the gears 86, the liquid stream is directed through the inlet passages 84 to the inlet side of the meshing portions of the gears, and then the stream is split in half by the two gears. This occurs as the liquid flows into the spaces between the teeth of the meshing gears that rotate in opposite directions as the gears rotate. Thus, the two liquid streams are carried in opposite directions around the periphery of the central recess 82a by the teeth of each of the counter-rotating gears, such that the two liquid streams converge near the outlet passages 85. Thus, the volume of liquid flowing between the gears 86 and the peripheral wall of the central recess 82a represents the volume of liquid per pulse. As the teeth of the adjacent gears mesh with each other, liquid is displaced from the spaces between the gear teeth of each gear, thereby forcing the liquid to pass into the outlet passages 85 adjacent to the meshing gears of the meshing pair. Thus, during this process, the pressurized liquid moving through the flow meter 80 exerts a rotational force on the gear 86, causing it to rotate at a particular speed. Sensors 88a, 88b are configured to measure this rotational speed of the gear 86 to determine the flow rate of the liquid moving through the flow meter 80. The gear tooth flow meter 80 is configured to provide a resolution of, for example, approximately 25 mg.

[0029] 7-9, gears 86 are constrained within recess 82a by a flat inner surface of housing cover 83. Each gear may be further constrained by a respective hardened support shaft 83a provided in housing cover 83. A membrane 83b is provided on the flat inner surface of housing cover 83 below each sensor 88a, 88b such that membrane 83b is located between sensors 88a, 88b and gears 86.

[0030] In another embodiment of the hot melt adhesive system, an accessory or auxiliary manifold 26' can be attached directly to the dispensing unit 20' as shown in FIG. 10A to retrofit an existing hot melt adhesive system with the adhesive tracking system 37. In another embodiment, the accessory manifold 26' can be remotely attached to the dispensing unit 20' via a transfer hose 43 as shown in FIG. 10B. It will be understood that the accessory manifold 26' can be retrofitted to hot melt adhesive systems that use piston type pumps or gear type pumps. A flow meter 80 can be attached to or integrated within the accessory manifold 26' such that hot melt adhesive received within the accessory manifold 26' can be directed through the flow meter 80. In some embodiments, the accessory manifold 26' can include an internal heater. When the accessory manifold 26' is remotely attached to the dispensing unit 20', the internal heater is powered by the transfer hose 43. When the auxiliary manifold 26' is attached directly to the dispensing unit 20', the internal heater is powered by the dispensing unit 20' itself. As shown in Figure 11A, the auxiliary manifold 26' includes an insulating jacket 27' that protects the flowmeter 80 and protects the user from burns. As shown in Figure 11B, the insulating jacket 27' has been removed from the auxiliary manifold 26', thus illustrating an embodiment of the auxiliary manifold 26' to which the flowmeter 80 can be directly attached.

[0031] The air pressure regulator 70 is shown in Figures 12A and 12B. The air pressure regulator 70 may be a diaphragm type pressure regulator with a pressure gauge 72 to monitor the pressure level and a rotary pressure adjustment knob 74 configured to adjust the pressure level to a desired magnitude. The air pressure regulator 70 is configured to turn the pump on and off and is in conjunction with a high flow solenoid having a flow coefficient of approximately 1.0 cv. Thus, during a pump stroke, the time required to repressurize is approximately 3 ms.

[0032] The adhesive tracking system 37 further employs a product detector 90 to determine the number of products. The product detector can be mounted with a field of view to image the products along the assembly line or to detect discontinuities between products along the assembly line. For example, the product detector 90 can be installed in the manufacturing line and mounted just prior to the first dispensing position. The product detector 90 is configured to sense the presence of a product to which adhesive is to be applied. As shown in FIG. 1, the product detector 90 is electrically connected to the controller 28. In other embodiments, the product detector 90 can be electrically connected to the flow meter 80, the manifold 26, or in other embodiments, a separate control unit (not shown). The controller includes a processor in electrical communication with both the flow meter 80 and the product detector 90 to monitor the flow output of the adhesive. In other embodiments, the processor can be included in the manifold 26 or in a separate control unit, for example. The measurement and reporting data collected by the adhesive tracking system can be used to improve process control of the hot melt adhesive system 10.

[0033] The processor determines a start time and a stop time for applying adhesive to the product based on the presence of the product received from at least one product detector 90. The processor also receives an amount of adhesive flowing out of the outlet 85 of the flow meter 80 at any one time. The processor then associates the amount of adhesive flowing out of the flow meter 80 from the start time to the stop time with the product. For example, the product detector 90 senses the leading edge to the trailing edge of the product as it moves along the production line and accordingly tallies the adhesive output from the flow meter 80 during that time. The processor may further calculate a weight of adhesive dispensed out of the outlet 85 of the flow meter 80 based on the received amount and / or calculate a volume of adhesive dispensed out of the outlet 85 of the flow meter 80 based on the received amount.

[0034] During operation of the adhesive tracking system 37, adhesive can be measured across the pitch of the product detector 90 to provide an average weight of adhesive per product, even if there are multiple dispensing stations at different locations on the production line. Additionally, a fixed product skip number can be used at start-up to ignore products to ensure that all applicators 48, 50 are applying adhesive before the adhesive tracking system 37 begins monitoring the products. Such a skip number should be long enough to allow all adhesive applicators 48, 50 to begin dispensing adhesive before checking begins. The skip number can be programmed down to a lower limit of zero so that skips are not possible for production lines that do not have products between glue stations.

[0035] The amount of adhesive applied to a product can be averaged for two or more products. In one embodiment, for example, the processor determines the start and end times of adhesive application for four products. The processor receives the amount of adhesive flowing out of the outlet 85 of the flow meter 80 from the start time to the end time. The processor then calculates the average amount of adhesive applied for the number of products detected by the product detector 90 from the start time to the end time, and associates the average amount of adhesive with each of the products.

[0036] Thus, the processor can determine the total amount of adhesive dispensed on the product and can also calculate the average amount of adhesive runoff dispensed or applied per product. Additionally, the processor can trigger a notification alarm if the average amount of adhesive per product falls outside a user-defined range, such as a predefined alarm threshold parameter. Such alarms can be generated for both high and low thresholds. Also, the number of products allowed through with over or under output is user adjustable. In particular, the processor can determine the number of consecutive products having an average amount of adhesive outside the predefined threshold parameters and trigger an alarm if said number of consecutive products exceeds a predefined alarm delay parameter. The notification alarm can be an audible or visual signal that alerts the user. Additionally, the alarm threshold parameters can be determined based on the average amount of adhesive applied to two or more products during the learning process. For example, the desired amount of adhesive applied to the products can be learned or manually entered by the user.

[0037] During the learning process, the processor determines the total amount of adhesive dispensed for all learned products and calculates the average amount of adhesive added per product. This average amount of adhesive applied is then used to determine the alarm thresholds. For example, the alarm thresholds may be user adjustable. The upper alarm point is independent of the lower alarm point. A notification alarm is activated upon completion of the learning process.

[0038] Also, during operation, when a production line first starts up, the minimum number of products, for example the first 40 products, may not be used in calculating the average amount of adhesive applied per product. Skipping products at start up causes all adhesive applicators 48, 50 to be active before calculating the average amount of adhesive added per product. The user can set the number of products to skip. For example, setting "0" will disable product skipping for systems that do not have more than one product between all adhesive applicators, such as for case sealing. Additionally, products may be skipped if no product signal is seen for a certain period of time, for example 10 seconds. This period of time is adjustable by the user. It should be understood that the process of skipping products may have a higher priority than the learning process. For example, the process of skipping products may be performed before the start of the learning process if the learning process is selected but product skipping is required.

[0039] The average amount of adhesive applied per product is determined based on a dispense period defined by the start and end times of adhesive flow detected by the product detector 90. The adhesive start and end times detected by the product detector for a number of products define a corresponding series of dispense periods. The processor calculates the average amount of adhesive runoff added to each product over each dispense period.

[0040] For example, the number of products averaged together for the calculation of the average product addition can be based on the number of products considered to achieve 2% resolution in adhesive addition. As described above, the number of products averaged together is determined during the learning process and can be adjusted by the user after the learning process. 2% resolution can be achieved when the total number of pulses from the flowmeter is 50 or more for N products, where N is the number of products averaged together to obtain the average amount of adhesive addition. In another example, if the learning process uses 4 products and the total number of flowmeter pulses seen during the learning process is 21, the number of products averaged together for the average addition is 4 products seen / (2% * 21 pulses seen) = 9.5 products, which is rounded up to the next highest integer, resulting in 10 products averaged together. Thus, the amount of adhesive is averaged across multiple products to calculate the target value.

[0041] The average amount of adhesive dispensed on a product can be represented by the weight applied per product over time or the average volume of adhesive dispensed per product. As explained above, if the average adhesive runoff applied per product is determined to be outside the alarm threshold and the number of consecutive out-of-tolerance products, i.e., the number of products outside the upper or lower thresholds, exceeds a value determined by an alarm delay parameter, such as the number of out-of-tolerance products allowed by the user, the processor triggers an alarm to notify the user. In some embodiments, an alarm output signal can trigger the controller 28 to stop production if the adhesive dispensing deviates beyond the user-specified upper and lower limits.

[0042] The measured weight allows the end user to optimize the adhesive application. Additionally, the user can set limits on the adhesive volume range to ensure process control and identify pattern volume discrepancies. Thus, the user can optimize the amount of adhesive applied to every product and reject products with too much or too little adhesive applied. Additionally, the user can also detect malfunctions that reduce flow, such as solenoid and module failures. Other malfunctions can include clogged nozzles, which the user can fix by increasing pressure or performing maintenance.

[0043] Additionally, a calibration factor (i.e., K-factor) allows fine tuning of the flow meter 80 for different operating conditions. For example, the actual adhesive weight from one or more products is measured and compared to the displayed adhesive weight. A new K-factor value can then be calculated using the following formula: New K-factor = Old K-factor * Displayed Weight / Actual Weight.

[0044] The user interface 29 of the adhesive tracking system 37 is in electronic communication with the controller 28 and includes a display screen that provides real-time data to the user, including average amount of adhesive add per product, total amount of adhesive add, average amount of adhesive add per hour, total and defective product counts, and alarm status and total alarms. Additionally, a USB port or other electronic media reader may be provided in communication with the processor to copy captured data logs and to provide access for system upgrades. Such data logs may be retained and stored for retrieval, for example, daily, weekly, or quarterly.

[0045] These specific embodiments described above are for illustrative purposes only and are not intended to limit the scope of the disclosure as otherwise described and claimed herein. Modifications and variations from the described embodiments may exist.

Claims

1. 1. A hot melt adhesive system comprising: an adhesive supply section for holding a solid or semi-solid hot melt adhesive; a heater associated with the adhesive supply for melting the solid or semi-solid hot melt adhesive into a liquid hot melt adhesive; a first manifold in fluid communication with the adhesive supply; a pump for pumping the liquid hot melt adhesive to the first manifold; an adhesive tracking system for monitoring an output of the liquid hot melt adhesive, the adhesive tracking system including a single flow meter configured to measure an amount of the liquid hot melt adhesive exiting the first manifold; the flow meter is configured to receive hot melt adhesive from the first manifold and to discharge the hot melt adhesive back to the first manifold; 13. A hot melt adhesive system comprising: a flow meter secured to the first manifold downstream of the pump.

2. 10. The hot melt adhesive system of claim 1, wherein the flow meter is configured to measure all of the hot melt adhesive flowing into or out of the first manifold.

3. 3. The hot melt adhesive system of claim 2, wherein the flow meter is mounted directly to the first manifold downstream of the pump.

4. The hot melt adhesive system of claim 2 , wherein the flow meter is removable from the first manifold.

5. 1) the flow meter inlet is configured to receive the liquid hot melt adhesive from the first manifold; and / or 2) The hot melt adhesive system of claim 2, wherein the flow meter outlet is configured to discharge the liquid hot melt adhesive into the first manifold.

6. a plurality of adhesive applicators configured to receive the hot melt adhesive from the first manifold and configured to apply the liquid hot melt adhesive to a substrate; The hot melt adhesive system of claim 2 , wherein the flow meter measures all of the hot melt adhesive received by the plurality of adhesive applicators.

7. 3. The hot melt adhesive system of claim 2, wherein the flow meter is the only flow meter in fluid communication with the first manifold.

8. 3. The hot melt adhesive system of claim 2, wherein the flow meter comprises a pair of rotatable gears configured to rotate in opposite directions relative to one another to provide a volumetric displacement of the hot melt adhesive through the flow meter, and at least one sensor configured to measure rotation of the pair of rotatable gears.

9. the adhesive tracking system further comprising a product detector configured to detect the presence of a product to which the liquid hot melt adhesive is applied, the adhesive tracking system further configured to determine a product count based on the product detector detecting the presence of the product; 2. The hot melt adhesive system of claim 1, wherein the adhesive tracking system is configured to associate the measured amount of the liquid hot melt adhesive flowing from the flow meter to the sensed product based on data including determined parameters of the product and the product count, and wherein the adhesive tracking system is configured to compare the associated amount of the liquid hot melt adhesive to a predetermined range to determine if the associated amount is outside of the predetermined range.

10. 10. The hot melt adhesive system of claim 1 further comprising an air pressure regulator for regulating the flow of air from an air supply to the pump.

11. 11. The hot melt adhesive system of claim 10, wherein the air pressure regulator is a diaphragm type regulator.

12. 2. The hot melt adhesive system of claim 1, wherein the single flow meter is downstream of the pump and includes an inlet and an outlet, the inlet configured to receive the liquid hot melt adhesive such that a flow rate of the liquid hot melt adhesive delivered from the pump equals a flow rate of the liquid hot melt adhesive received by the inlet.

13. Further comprising a discharge unit including the adhesive supply unit, The adhesive tracking system comprises: an auxiliary manifold in fluid communication with the discharge unit; a product detector configured to detect the presence of a product to which the liquid hot melt adhesive is to be applied; a controller comprising a processor in communication with the flow meter and the product detector and configured to determine a total amount of the liquid hot melt adhesive dispensed and an average amount of the liquid hot melt adhesive dispensed per product; 10. The hot melt adhesive system of claim 1, wherein the flow meter is in fluid communication with and attached to the auxiliary manifold.

14. 1. A hot melt adhesive system comprising: an adhesive supply section for holding a solid or semi-solid hot melt adhesive; a heater associated with the adhesive supply for melting the solid or semi-solid hot melt adhesive into a liquid hot melt adhesive; a first manifold in fluid communication with the adhesive supply; a pump for pumping the liquid hot melt adhesive to the first manifold; an adhesive tracking system for monitoring an output of the liquid hot melt adhesive, the adhesive tracking system including a single flow meter configured to measure an amount of the liquid hot melt adhesive flowing from the first manifold; a discharge unit including the adhesive supply unit, The adhesive tracking system comprises: an auxiliary manifold in fluid communication with the discharge unit; a product detector configured to detect the presence of a product to which the liquid hot melt adhesive is to be applied; a controller comprising a processor in communication with the flow meter and the product detector and configured to determine a total amount of the liquid hot melt adhesive dispensed and an average amount of the liquid hot melt adhesive dispensed per product; The hot melt adhesive system, wherein the flow meter is in fluid communication with and attached to the auxiliary manifold.

15. the auxiliary manifold is attached directly to the discharge unit; 15. The hot melt adhesive system of claim 14, wherein the flow meter comprises a housing body having a hollow central recess.

16. 15. The hot melt adhesive system of claim 14, wherein the auxiliary manifold is remotely mounted relative to the dispensing unit.

17. A method for applying adhesive to a substrate, comprising:

15. The hot melt adhesive system of claim 14, further comprising at least one hose in fluid communication with said auxiliary manifold and said at least one adhesive applicator for transporting said liquid hot melt adhesive from said auxiliary manifold to said at least one adhesive applicator.

18. 20. The hot melt adhesive system of claim 17, wherein the flow meter is mounted on an end of the at least one hose in a location proximate to the at least one adhesive applicator.

19. The adhesive tracking system further comprising: a product detector configured to detect the presence of a product to which the liquid hot melt adhesive is to be applied; 13. The hot melt adhesive system of claim 1, further comprising: a controller comprising a processor in communication with the flow meter and the product detector and configured to determine a total amount of the liquid hot melt adhesive dispensed and an average amount of the liquid hot melt adhesive dispensed per product.

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