System and method for monitoring the flow of a liquid adhesive

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 on April 4, 2016, the disclosure of which is incorporated herein by reference in its entirety.

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

Background Art

[0003] Dispensing systems that discharge thermoplastic hot - melt adhesives or other fluid materials are widely used in the manufacturing and packaging industries. For example, hot - melt adhesives may be used, inter alia, for carton sealing, case sealing, tray forming, pallet stabilization, and non - woven fabric applications. Typically, the hot - melt adhesive is contained in an adhesive supply, such as a tank or hopper of an adhesive melter, and is provided from the adhesive supply. Accordingly, the hot - melt adhesive is heated, melted, and pumped to a dispenser, such as a discharge applicator or other applicator, that applies the hot - melt adhesive to a product or substrate.

[0004] Typically, a manifold is used to direct a liquid hot melt adhesive into a plurality of flow streams and output it through a hose 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 the hot melt adhesive in the hot melt adhesive dispensing system. Conventional metering systems are typically in fluid communication with each respective outlet of the dispensing system and are capable of individually monitoring the flow of the liquid material through each outlet. This configuration is suitable for low discharge flow rates and ensures that the restriction of the flow through one liquid outlet does not affect the flow of liquid from the remaining liquid outlets.

[0005] However, the cost of installing individual flow meters at each liquid outlet is not economically practical, especially for a dispensing system that may have 4 to 6 applicators. Moreover, multiple flow meters require more maintenance costs due to the large number of components. Furthermore, conventional metering systems are not retrofittable to existing dispensing systems. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Therefore, there is a need for a metering system for use with a hot melt adhesive dispensing unit that addresses these drawbacks, for example, by providing a single flow meter in direct fluid communication with the manifold of a hot melt adhesive system to monitor the amount of adhesive dispensed to all products. MEANS FOR SOLVING THE PROBLEMS

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

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

[0009] In another embodiment, a flow meter used in a hot melt adhesive system including an adhesive supply unit, a manifold, a heater, and at least one hose connected to a dispensing applicator is disclosed. 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 the 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 proximate to the hollow central recess of the housing body. The flow meter further includes a pair of rotatable gears provided within the hollow central recess and rotatably fixed between the housing body and the housing cover, and at least one sensor configured to measure the amount of hot melt adhesive flowing through the flow meter.

[0010] In another embodiment, a hot melt adhesive system includes an adhesive supply unit that holds a solid or semi-solid hot melt adhesive, a heater associated with the adhesive supply unit that melts the solid or semi-solid hot melt adhesive into a liquid hot melt adhesive, a first manifold in fluid communication with the adhesive supply unit, a pump that pumps the liquid hot melt adhesive from the heater to the first manifold, a pneumatic regulator that regulates the flow of air from an air supply unit to the pump, at least one adhesive applicator configured to apply the liquid hot melt adhesive to a substrate, and an adhesive tracking system that monitors the output of the liquid hot melt adhesive.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10A

Figure 10B

Figure 11A

Figure 11B

Figure 12A

Figure 12B

MODE FOR CARRYING OUT THE INVENTION

[0012] As shown in FIG. 1, the hot melt adhesive system 10 includes a discharge unit 20 that houses a solid or semi-solid hot melt adhesive 24a such as pellets and melts it, an adhesive supply unit 22, a manifold 26 connected to the adhesive supply unit 22, a control device 28, and a user interface 29. The adhesive supply unit 22 can be, among other things, a tank-type melter or a grid and reservoir melter. During melting, the solid or semi-solid hot melt adhesive 24a stored in the adhesive supply unit 22 changes into a liquid hot melt adhesive 24. The adhesive supply unit 22 includes a side wall 30, a removable cover 31, and a base 32 having one or more adhesive supply unit heaters 34 that melt and heat the hot melt adhesive 24a and the liquid hot melt adhesive 24 within the adhesive supply unit 22. An adhesive supply unit outlet 36 proximate to the base 32 couples to a passage 38 that connects to an inlet 40 of the manifold 26.

[0013] The manifold 26 can be directly integrated into the discharge unit 20 of the hot melt adhesive system 10 such that the manifold 26 is attached to the side wall 30 of the adhesive supply unit 22. A discharge unit 20 having such an integrated manifold 26 is shown in FIGS. 2A and 2B. As will be described in more detail later, in other embodiments, an auxiliary manifold can be retrofitted to other hot melt adhesive systems by attaching it directly or indirectly to the discharge 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 to pump the liquid hot melt adhesive 24 from the adhesive supply section 22 to the manifold 26, where the liquid hot melt adhesive 24 is divided into separate streams. A pump motor 59 drives the pump 58. The manifold 26 is attached to the side wall 30 of the adhesive supply section 22 by a spacer 41 and is spaced from the adhesive supply section 22 by a distance 42 sufficient to provide insulation from the manifold 26 to the adhesive supply section 22. The manifold 26 has a plurality of outlet ports 44 into which a heated hose 46 can be fitted, and the hose 46 is attached to one or more adhesive applicators 48, 50 to supply the liquid adhesive 24 to the applicators 48, 50. Although FIG. 1 shows the adhesive supply section 22 in physical proximity to the manifold 26, other configurations are possible where the source of the hot melt adhesive is physically separated from the manifold. In such a configuration, two or more pumps can be used to move the hot melt adhesive from the adhesive supply section 22 to the final application point.

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

[0016] Also, as shown in FIG. 1, the manifold 26 is positioned adjacent to the adhesive supply unit 22 between the adhesive supply unit 22 and the control device 28. It will be understood that other configurations in which the manifold 26 is located at the center of the unit 20 can also be used. The outlet port 44 of the manifold 26 is disposed substantially at the center of the dispensing unit 20, and the distances from a given outlet port 44 to the tank side or the control device side of the unit 20 are substantially the same. This centered arrangement of the outlet ports 44 enables the use of hoses 46 of the same length to supply the liquid adhesive 24 to the dispensing applicators 48, 50 located on both sides of the dispensing unit 20. The manifold 26 can be separate from the adhesive supply unit heater 34 and can include a manifold heater 56 that can be independently controlled by the control device 28. It will be understood that a single heater can be used to heat the adhesive supply unit 22 and the manifold 26.

[0017] The dispensing unit 20 includes a control device 28 that houses the power supply unit and the electronic control unit of the dispensing unit 20. The hoses 46 are electrically coupled to the control device 28 by a cord set 62 associated with each hose 46. The control device 28 individually monitors and adjusts the adhesive supply unit heater 34, the manifold heater 56, the hoses 46, and the applicator heater 53, melts the solid or semi-solid adhesive 24a housed within the adhesive supply unit 22, and supplies it to the applicators 48, 50 while maintaining the temperature of the liquid adhesive 24 to ensure an appropriate viscosity of the adhesive 24 discharged by the adhesive discharge module 54.

[0018] Regarding the heating mechanism of the hot melt adhesive system 10, the control device 28 is electrically coupled to heaters including the adhesive supply unit heater 34, the manifold heater 56, and the applicator heater 53, and further any hose heater. Also, the control device 28 can be coupled to various temperature sensors within the hot melt adhesive system 10 that can be associated with or included in the adhesive supply unit heater 34, the manifold heater 56, the applicator heater 53, and any hose heater. The control device 28 individually monitors and adjusts the adhesive supply unit heater 34, the manifold heater 56, the applicator heater 53, and any hose heater to melt the solid or semi-solid hot melt adhesive 24a contained within the adhesive supply unit 22 and to maintain the appropriate viscosity of the liquid hot melt adhesive 24 that is supplied to the applicators 48, 50 and discharged by the adhesive discharge module 54. For example, the control device 28 receives temperature information from the temperature sensors and transmits heater control commands to each heater to adjust the temperature. Such heater control commands can raise or lower the temperature of any or all heaters in the hot melt adhesive system 10.

[0019] The pump 58 is located outside the adhesive supply unit 22 and is connected to a pneumatic regulator 70 that receives air from the air supply unit 61. More specifically, the pneumatic regulator 70 is attached to the discharge unit 20 and is connected to the air supply unit 61. In some embodiments, the pump 58 can be attached to the manifold 26 and can be heated by the manifold heater 56. This configuration allows for a larger tank opening 60, increases the tank capacity, and reduces the time required to heat the pump 58. Further, 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 control device 28 by respective cords 63a, 63b associated with each sensor. At least one product detector 90, such as an optical sensor, is also electrically coupled to the control device 28.

[0020] The manifold 26, flow meter 80, product detector 90, control device 28, and user interface 29 are components of an adhesive tracking system 37 that monitors the adhesive applied to a product or substrate during operation to provide useful system data and alarms to the user, including the total amount of adhesive discharged and the average amount of adhesive discharged per product. Referring again to FIG. 3, further features regarding 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 divided into a plurality of 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 rate information using at least one flow sensor 88 that communicates electrically with the control device 28 and the user interface 29 to provide feedback to the user. In some embodiments, a pair of flow sensors 88a, 88b that provide a quadrature output (orthogonal output) are provided. The reason for this is that during the stroke of the piston pump, the material actually flows in the reverse direction as well, and the quadrature output makes it possible to subtract this reverse flow from the forward flow in order to maintain a high level of accuracy. In embodiments using a gear pump with no reverse flow, a single sensor is sufficient.

[0021] The user interface 29 operates in conjunction with the control device 28 to provide the user with information regarding the heating function of the hot melt adhesive system 10. For example, the user interface 29 presents information regarding the adhesive temperature, heater temperature, etc. The user interface 29 also includes a control section for adjusting parameters related to the heating of the hot melt adhesive system 10. Further, the user interface 29 and the control device 28 also provide the user with information regarding the adhesive tracking system 37, as will be described in more detail later.

[0022] Referring again to FIGS. 2A and 2B, a dispensing unit 20 of a hot melt adhesive system is shown, which includes a manifold 26, a control device 28, and a user interface 29. In FIG. 2A, the manifold 26 is shown to have a heat insulation 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, and a flow meter 80 in fluid communication with the manifold 26 is exposed.

[0023] The adhesive tracking system 37 uses a flow meter 80 that directly measures the output of the adhesive. In some embodiments, the flow meter 80 can be removably connected to the manifold 26. Referring to FIGS. 4-7, for example, the flow meter 80 includes 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 a fastener 87a such as a screw or a bolt. The flow meter 80 further includes 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 with the manifold 26. For example, the housing body 82 can be integrated with the manifold 26 such that the housing cover 83 can be removably connected to the housing body 82 via the fastener 87b. In another embodiment, individual components of the flow meter 80 such as the gear 86, the pin 81, and the bush 81a, which will be described in detail later, can be incorporated into the housing cover 83, and the housing cover 83 can be directly removably connected to the manifold 26 via the fastener 87b so that the housing body 82 is not used. In yet another embodiment, individual components of the flow meter 80 such as the gear 86, the pin 81, and the bush 81a can be directly integrated with the manifold 26 such that the housing cover 83 can be directly removably connected.

[0024] The flow meter 80 further includes 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 are shown. In particular, the pair of sensors 88a, 88b are configured to measure the rotation of the rotatable drive gear 86 and determine the amount of adhesive flowing out of the outlet 85. The outlet 85 is in fluid communication with the manifold 26, whereby the liquid adhesive is returned to the manifold 26 and dispersed to various hoses 46 directly connected to the manifold 26. In some embodiments, the outlet 85 can be directly connected to a hose connected to the adhesive applicator.

[0025] The housing body 82 also includes an elastomeric seal 89, such as an elongated or oval O-ring, to maintain a watertight seal by the cover to prevent fluid leakage from the flow meter. Further, a plurality of fasteners 87a, 87b are 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 to the pump 58 or any hose 46.

[0026] The gears 86 are housed within the hollow central recess 82a of the housing body 82 so as to rotate freely about the 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 substantially linear series of meshing flow measuring spur gears, each configured to rotate about respective pins 81 provided in corresponding bushes 81a within the housing body 82. The spur gears 86 are in substantially the same plane, and each spur gear is positioned parallel and spaced from at least one adjacent spur gear. Further, the spur gears 86 are positioned such that the respective axes of rotation of the gears are positioned along a common centerline. Also, the spur gears 86 are positioned such that the teeth of each spur gear mesh with the teeth of an adjacent spur gear.

[0027] The inlet passage 84 provides a conduit between the liquid source of the manifold 26 and the inlet side of a pair of meshing gears 86. Similarly, the outlet passage 85 provides a conduit between the discharge side of the pair of meshing gears 86 and the manifold 26. The gears 86 are in fluid communication with the inlet passage 84 that directs a pressurized stream of liquid into the recess 82a and toward the inlet side of the pair of meshing 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 the adjacent gear rotates in a clockwise direction. By using counter-rotating gears 86, positive displacement for the accurate metering of liquid hot melt adhesive is provided.

[0028] As a result of this rotation of the gears 86, after a stream of liquid is directed to the inlet side of the meshing portion of the gears via the inlet passage 84, the stream is split in half by the two gears. This occurs as liquid flows into the spaces between the teeth of a pair of meshing gears that rotate in opposite directions during rotation of the gears. Thus, the two liquid streams are each carried in opposite directions around the periphery of the central recess 82a by the teeth of each gear rotating in opposite directions, and the two liquid streams are configured to converge near the outlet passage 85. Thus, the volume of liquid flowing between the gear 86 and the peripheral wall of the central recess 82a represents the volume of liquid per pulse. As the teeth of each gear of the adjacent gears mesh with one another, liquid moves from the spaces between the gear teeth of each gear, thereby passing the liquid into the outlet passage 85 adjacent to the pair of meshing gears. Thus, during this process, the pressurized liquid moving through the flow meter 80 exerts a rotational force on the gear 86, rotating the gear 86 at a specific speed. The 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 approximately 25 mg, for example.

[0029] As shown in FIGS. 7 to 9, the gear 86 is restricted within the recess 82a by the flat inner surface of the housing cover 83. Each gear can be further restricted by respective hardened support shafts 83a provided on the housing cover 83. A thin film 83b is provided on the flat inner surface of the housing cover 83 under each of the sensors 88a, 88b, so that the thin film 83b is positioned between the sensors 88a, 88b and the gear 86.

[0030] In another embodiment of the hot melt adhesive system, in order to retrofit an adhesive tracking system 37 to an existing hot melt adhesive system, as shown in FIG. 10A, an accessory or auxiliary manifold 26' can be directly attached to the dispensing unit 20'. In another embodiment, the accessory manifold 26' can be attached remotely 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 a hot melt adhesive system using a piston pump or a gear pump. A flow meter 80 can be attached to the accessory manifold 26' or integrated within the accessory manifold 26' such that the 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 attached remotely to the dispensing unit 20', the internal heater receives power from the transfer hose 43. When the accessory manifold 26' is directly attached to the dispensing unit 20', the internal heater receives power from the dispensing unit 20' itself. As shown in FIG. 11A, the auxiliary manifold 26' includes a heat insulating jacket 27' that protects the flow meter 80 and protects the user from burns. As shown in FIG. 11B, the heat insulating jacket 27' is removed from the auxiliary manifold 26', thus showing one embodiment of the auxiliary manifold 26' to which the flow meter 80 can be directly fixed.

[0031] The pneumatic regulator 70 is shown in FIGS. 12A and 12B. The pneumatic regulator 70 can be a diaphragm type pressure regulator, and includes a pressure gauge 72 for monitoring the pressure level, and a rotary pressure adjustment knob 74 configured to adjust the pressure level to a desired magnitude. The pneumatic regulator 70 is configured to turn the pump on and off, and is interlocked with a high flow solenoid having a flow coefficient of approximately 1.0 cv. Therefore, during the pump stroke, the time required for repressurization is approximately 3 ms.

[0032] The adhesive tracking system 37 further uses a product detector 90 for determining the number of products. The product detector can be mounted with a field of view for imaging the products along the assembly line or detecting the gaps between products along the assembly line. For example, the product detector 90 can be installed on the manufacturing line and mounted immediately before the first discharge position. The product detector 90 is configured to detect the presence of the product to which the adhesive is applied. As shown in FIG. 1, the product detector 90 is electrically connected to the control device 28. In other embodiments, the product detector 90 can be electrically connected to the flow meter 80, the manifold 26, or another separate control unit (not shown) in other embodiments. The control device includes a processor that electrically communicates with both the flow meter 80 and the product detector 90 for monitoring the flow output of the adhesive. In other embodiments, the processor can be included in, for example, the manifold 26 or a separate control unit. The measurement and reporting data collected by the adhesive tracking system can be used to improve the process control of the hot melt adhesive system 10.

[0033] Based on the presence of the product received from at least one product detector 90, the processor determines the start time and end time for applying the adhesive to the product. The processor also always receives the amount of adhesive flowing out from the outlet 85 of the flow meter 80. Then, the processor associates the amount of adhesive flowing out from the flow meter 80 from the start time to the end time with the product. For example, when the product moves along the production line, the product detector 90 detects from the leading edge to the trailing edge of the product, and accordingly aggregates the adhesive output from the flow meter 80 during that time. The processor can further calculate the weight of the adhesive discharged from the outlet 85 of the flow meter 80 based on the received amount and / or calculate the volume of the adhesive discharged from the outlet 85 of the flow meter 80 based on the received amount.

[0034] During the operation of the adhesive tracking system 37, even if there are multiple dispensing stations at different locations on the production line, the adhesive can be measured over the pitch of the product detector 90, and the average weight of the adhesive for each product can be obtained. Further, in order to ensure that all applicators 48, 50 are applying the adhesive before the adhesive tracking system 37 starts monitoring the product, the product can be ignored using a fixed number of product skips at startup. Such a number of skips should be long enough for all adhesive applicators 48, 50 to start discharging the adhesive before the start of the verification. The number of skips can be programmed down to a lower limit of zero so that it cannot be skipped for a production line without products between the gluing stations.

[0035] The amount of adhesive applied to the product can be averaged over two or more products. In one embodiment, for example, the processor determines the start time and end time of applying the adhesive to four products. The processor receives the amount of adhesive flowing out from the outlet 85 of the flow meter 80 from the start time to the end time. Then, the processor calculates the average amount of adhesive applied with respect to 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] Accordingly, the processor can determine the total amount of adhesive discharged onto the product and can also calculate the average outflow amount of the adhesive discharged or added for each product. Further, the processor can trigger a notification alarm when the average amount of adhesive for each product is outside a user-specified range such as a predetermined alarm threshold parameter. Such alarms can be generated for both high and low thresholds. Also, the number of products allowed to pass with excessive or insufficient output is user-adjustable. In particular, the processor can determine the number of consecutive products having an average adhesive amount outside a predetermined threshold parameter and can trigger an alarm when the number of the above-mentioned consecutive products exceeds a predetermined alarm delay parameter. The notification alarm can be an audible or visual signal to warn the user. Further, the alarm threshold parameter can be determined based on the average amount of adhesive applied to two or more products during a learning process. For example, the desired amount of adhesive applied to a product can be learned or manually input by the user.

[0037] During the learning process, the processor determines the total amount of adhesive discharged onto all products to be learned and calculates the average amount of adhesive addition for each product. Next, an alarm threshold is determined using the average amount of the applied adhesive. For example, the alarm threshold can be user-adjustable. The upper limit alarm point is independent of the lower limit alarm point. The notification alarm becomes effective at the end of the learning process.

[0038] Also, during operation, at the first startup of the production line, the minimum number of products, for example, the first 40 products, may not be used for calculating the average amount of adhesive applied to each product. By skipping products at startup, all the adhesive applicators 48, 50 are activated before calculating the average amount of adhesive addition per product. The user can set the number of products to skip. For example, setting "0" disables product skipping for a system that does not have more than two products between all adhesive applicators for case sealing, etc. Further, if a product signal is not seen for a certain time, for example, 10 seconds, the product can be skipped. This time is adjustable by the user. It should be understood that the process of skipping products can have a higher priority than the learning process. For example, the process of skipping products can be executed 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 to each product is determined based on the discharge period defined by the start time and end time of the adhesive flow detected by the product detector 90. The start time and end time of the adhesive detected by the product detector for a plurality of products define a corresponding series of discharge periods. The processor calculates the average outflow amount of the adhesive added to each product over each discharge period.

[0040] For example, the number of products averaged overall for the calculation of the average addition of a product can be based on the number of products considered to achieve a resolution of 2% in adhesive addition. As described above, the number of products averaged is determined during the learning process and can be adjusted by the user after the learning process. The 2% resolution can be achieved when the total number of pulses from the flow meter for N products is 50 or more. Here, N is the number of products averaged to obtain the average amount of adhesive addition. In another example, if the learning process uses 4 products and the total number of pulses of the flow meter seen during the learning process is 21, the number of products averaged overall for the average of the addition is the 4 products seen÷(2%*the 21 pulses seen)=9.5 products, and by rounding this up to the next larger integer, the number of products averaged overall becomes 10. Thus, in order to calculate the target value, the amount of adhesive is averaged over a plurality of products.

[0041] The average amount of adhesive discharged onto the product can be represented by the weight applied per product over time or the average volume of adhesive discharged per product. As explained above, when it is determined that the average outflow of the adhesive applied per product is outside the alarm threshold, and the number of consecutive out-of-tolerance products, that is, the number of products outside the upper or lower threshold, exceeds the value determined by alarm delay parameters such as the number of out-of-tolerance products permitted by the user, the processor triggers an alarm to notify the user. In some embodiments, when the discharge of the adhesive deviates beyond the user-specified upper and lower limits, the control device 28 can be triggered by the alarm output signal to stop the production.

[0042] Based on the measured weight, the end user can optimize the adhesive application. Furthermore, the user can set the width limit of the adhesive amount to ensure process control and identify inconsistencies in the pattern volume. Thus, the user can optimize the amount of adhesive applied to the entire product and reject products with excessive or insufficient applied adhesive. Moreover, the user can also detect operational failures that reduce flow, such as solenoid and module failures. Other operational failures can include nozzle clogging, which can be repaired by the user increasing the pressure or performing maintenance.

[0043] Furthermore, the calibration coefficient (i.e., the K coefficient) enables 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 with the displayed adhesive weight. And a new value of the K coefficient can be calculated using the following formula: New K coefficient = Old K coefficient * Displayed weight / Actual weight.

[0044] The user interface 29 of the adhesive tracking system 37 communicates electrically with the control device 28 and includes a display screen that provides real-time data to the user. The real-time data includes the average amount of adhesive addition per product, the total amount of adhesive addition, the average amount of adhesive addition per hour, the total number of products and the number of defective products, as well as the alarm status and total alarms. Furthermore, a USB port or other electronic media reader can be provided in communication with the processor to copy the acquired data log and provide access for system upgrades. Such data logs can be retained and stored for retrieval, for example, daily, weekly, or quarterly.

[0045] These specific embodiments described above are for illustrative purposes and are not intended to limit the scope of the present disclosure as separately described and claimed herein. Changes and modifications from the described embodiments may exist.

Claims

1. A hot melt adhesive system comprising a flow meter, wherein the hot melt adhesive system comprises an adhesive supply unit, a manifold, a heater, and at least one hose connected to a dispensing applicator, the flow meter comprising 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 the hot melt adhesive back to the manifold, a housing cover removably attached to the housing body and having a flat inner surface proximate to the hollow central recess of the housing body, a pair of rotatable gears provided within the hollow central recess and rotatably fixed between the housing body and the housing cover, at least one sensor configured to measure the amount of hot melt adhesive flowing through the flow meter, a hot melt adhesive system.

2. The hot melt adhesive system according to claim 1, wherein the housing body is removably connected to the manifold.

3. The hot melt adhesive system according to claim 1, wherein the housing body is integral with the manifold.

4. The hot melt adhesive system according to claim 1, wherein the at least one sensor comprises a pair of sensors configured to provide a quadrature output.

5. The hot melt adhesive system according to claim 4, wherein the pair of sensors are magnetic pickup sensors configured to measure the rotation of the pair of rotatable gears.

6. The hot melt adhesive system according to claim 1, wherein the manifold includes at least one outlet port directly connected to the at least one hose.

7. The hot melt adhesive system according to claim 1, further comprising an elastomer seal within the housing body.

8. The hot melt adhesive system according to claim 1, wherein the gears are each configured to rotate about respective pins provided in corresponding bushes within the housing body and are straight series of meshing spur gears.

9. The hot melt adhesive system according to claim 8, wherein the spur gears are substantially in the same plane and the teeth of each spur gear are positioned to mesh with each other.

10. The hot melt adhesive system according to claim 9, wherein each gear is configured to rotate in opposite directions relative to each other so as to cause a volumetric displacement of the hot melt adhesive passing through the flow meter.

11. The hot melt adhesive system according to claim 8, further comprising a pair of support shafts provided on the housing cover configured to hold the respective spur gears within the recess of the housing body.

12. The hot melt adhesive system according to claim 11, further comprising a thin film provided on the flat inner surface of the housing cover under the at least one sensor, the thin film being arranged between the at least one sensor and the gear.

13. The hot melt adhesive system according to claim 1, wherein the manifold is heated.

14. The hot melt adhesive system according to claim 1, wherein the manifold is in fluid communication with the adhesive supply section.

15. The hot melt adhesive system according to claim 1, comprising a pump for pumping the hot melt adhesive from the heater to the manifold.

16. The hot melt adhesive system according to claim 1, wherein the at least one hose is in fluid communication with the manifold and the discharge applicator for transferring the hot melt adhesive from the manifold to the discharge applicator.

17. The hot melt adhesive system according to claim 1, wherein the at least one hose includes two hoses fluidly connecting the manifold to the discharge applicator.

Images