MX2007015554A - Liquid adhesive dispensing system - Google Patents

Abstract

A liquid adhesive dispensing system operable for more uniformly applying liquid adhesive foam onto moving substrates, notwithstanding changes in line speed, adhesive liquid flow rates, or foaming/atomizing air pressures. The illustrated liquid adhesive system includes a header having a plurality of air atomizing spray guns;the spray guns each having a respective variable speed positive displacement pump for directing a metered quantity of liquid adhesive from a liquid adhesive supply to the respective spray gun;and a control for controlling the operating speed of the positive displacement pumps in relation to the speed of the moving substrate and the foaming/atomizing air pressure to the spray guns in relation to the operating speed of the positive displacement pumps. The control further is operable for monitoring pressures across the positive displacement pumps for insuring the accurate direction of metered quantities of liquid to the spray guns. The spray guns are adapted for enhanced liquid adhesive foaming and atomization, and the header is convertible into a closed housing structure effective for containing cleaning and purge liquids during an automatically operable cleaning cycle of operation.

Description

"LIQUID ADHESIVE DISTRIBUTION SYSTEM" FIELD OF THE INVENTION The present invention relates in general terms to the manufacture and processing of laminated sheet material, and more particularly, to a system for distributing liquid adhesive on a sheet or moving sheet substrate in the manufacture of sheet metal laminate materials. multiple, such as toilet paper, facial tissues, napkins, paper towels, non-woven sheet material, and the like.

BACKGROUND OF THE INVENTION Various techniques have been used and proposed for joining laminated sheet material capable. These techniques have included mechanically forcing the layers together to interlock the laminated layers, applying thermoprinting adhesives to the laminated sheet material to adhesively bond the laminated layers, and applying water-based adhesives to the sheets. The systems to carry out these techniques have suffered several disadvantages, including the need for equipment that was expensive in terms of construction and difficult to maintain, creating mechanical or adhesive bonds of the laminated layers that were inconsistent or inadequate, being difficult to control reliably during changes in the processing of speeds and conditions, resulting in excessive application, waste, slow drying, and purging through applied liquid adhesives. Efforts to facilitate the application of liquid adhesives through atomization of pressurized air from liquid adhesive are also considered a matter of problems that impair a uniform or reliable application of the adhesive. Since the atomizing air pressure can create a back pressure in the liquid adhesive supplied to an aerosol or dispensing nozzle, changes in the atomization air pressure, such as during a change in processing, can alter the flow magnitude of the liquid through the spray nozzle. Therefore, it has been difficult to precisely control the processing parameters when the atomization air pressures and / or the liquid adhesive are modified for different product requirements. In addition, spraying the adhesive with such spray systems is relatively dirty and ineffective due to a high transfer efficiency, purge, fogging, and adhesive formation on the machinery components.

BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a liquid adhesive distribution system for laminated sheet material that is adapted to more uniformly apply liquid adhesives notwithstanding changes in processing conditions. Another object is to provide a liquid adhesive dispensing system as mentioned above that is operable to generate a predetermined and uniformly controlled fine bubble foam of liquid adhesive prior to dispensing onto the moving sheet material. A further object is to provide a liquid adhesive distribution system of the above kind in which the foaming and / or atomization of the liquid air of the liquid adhesive can be effected and controlled uniformly, notwithstanding the changes in the line speed of the substrate material. mobile, changes in the magnitude of liquid adhesive flow, or changes in atomizing air pressure. Yet another object is to provide a liquid adhesive distribution system of such type that allows for selective control and changes in foam density and / or application rates as required during different lamination processes of ho a.

- - Yet another object is to provide the distribution system that is effective to generate and apply a water-based liquid adhesive in a manner that facilitates faster drying and minimizes the damage of the purge through the paper substrate. Another object is to provide a system of liquid adhesive dispensing of the above type of which includes a plurality of liquid adhesive dispensing nozzles positioned across the width of a moving sheet of laminated material to allow the application of selected patterns and / or concentrations of adhesive to the moving sheet material . A further object is to provide such a liquid adhesive distribution system that is adapted for a relatively inexpensive construction and easy maintenance. A related object is to provide such an adhesive dispensing system that allows automated cleaning of the adhesive dispensing nozzles and the associated liquid adhesive supply components.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the invention will become apparent after reading the following detailed description and after reference to the drawings, in which: Figure 1 is a perspective view of a header spraying a liquid adhesive distribution system according to the invention shown directing a liquid adhesive foam on a moving sheet, such as a fabric of laminated material to be used in the manufacture of a laminated product; Figure 2 is a vertical cross section of the illustrated spray header taken in the plane of line 2-2 in Figure 1; Figure 3 in a vertical cross section, similar to Figure 2, shows the pulvepzadora header in a closed self-cleaning condition; Figure 4 is a schematic view of a liquid adhesive distribution system according to the invention using a spray head such as that shown in Figure 1; Figure 5 is an enlarged vertical cross section of one of the liquid adhesive dispensing guns of the illustrated header; Figure 5A is an enlarged fragmentary vertical section of a nozzle graft included in the adhesive dispensing gun shown in Figure 5; Figure 6 is a fragmentary cross-section of an alternative embodiment of the spray gun - for use in the liquid distribution system of the present invention; Figure 6A is an enlarged fragmentary cross section of the spray nozzle of the spray gun shown in Figure 6; Figure 7 is a diagrammatic representation showing particularly the liquid adhesive supply control system for the illustrated distribution system; Figure 7A is an enlarged fragmentary section of one of the positive displacement pumps, taken in the plane of the line 7A in Figure 7; Figure 8 is a perspective view of a pump apparatus used in the liquid adhesive supply control system illustrated to direct the liquid adhesive from a supply of liquid adhesive to the spray head; Figures 9 and 10 are elevational and side views, respectively, of the pumping apparatus shown in Figure 8; Figures 11 and 12 are more detailed schematic diagrams of the liquid direction control system for the illustrated distribution system; and Figure 13 is a diagrammatic representation of an alternative embodiment of a liquid adhesive control system for the illustrated distribution system. Although the invention is susceptible to various modifications and alternative constructions, a certain illustrated embodiment thereof has been demonstrated in the drawings and will be described in more detail below. However, it should be understood that there is no intention to limit the invention to the specific form described, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents that are within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now more particularly to the drawings, there is shown an illustrative liquid adhesive distribution system 10 according to the invention operable to direct the water-based liquid adhesive onto a moving sheet metal or sheet 11, such as the manufacture of • laminated sheet materials, including toilet paper, facial tissues, napkins, paper towels, and the like. The illustrated adhesive distribution system 10 basically includes a spray head 12 (Figures 1-6), a supply of liquid adhesive 14 (Figures 7 and 11), and a liquid adhesive supply control system 15 (Figures 7, 11). and 12), to control the supply of liquid adhesive from the liquid supply 14 to the spray head 12. Those skilled in the art will understand that after distribution of the adhesive on the mobile substrate 11., the substrate can be joined to other moving sheet in the known manner in order to form a sheet metal laminate. In addition, although the invention has a particular utility for distributing water-based adhesives in the manufacture of rolled products, it will be understood that the liquid distribution system 10 can be used to distribute other types of liquids in other applications. The spray header 12 in this case includes a plurality of spray guns or nozzle assemblies 20 placed in transversely spaced relationship across the width of the movable substrate 11. The spray guns of 20 are supported on a common cross bar 21, which at its it is supported on opposite ends by the rods 22. Each of the spray guns 20 is screwed on the cross bar 21 in a parallel manner with each other, and the support rods 22 are preferably installed for selective rotary movement in order to allowing the desired direction of the discharge adhesives from the guns in a predetermined angular relationship with the moving substrate. The illustrated puller header 12 has a longitudinally extending housing or housing 24 installed in surrounding relationship with the spray guns 20, the housing 24 having an open end 25 from which the adhesive is discharged from the spray guns 20. As graphically depicted in FIG. Figure 2, and as it will become apparent, the fluid supply lines for the spray guns 20 extend lengthwise and are contained in a protective manner within the housing 24. It will be understood that the number of spray guns will be able to vary depending on the a particular spray application. In carrying out an aspect of the invention, each of the spray guns 20 comprises an internal mix air atomizing spray nozzle a thin adhesive foam within the nozzle which can be distributed in a controlled manner over a segment or side area default of the mobile substrate. Each of the spray guns 20 illustrated, as graphically depicted in Figure 5, includes a main body or housing 26, a rear housing cover 28 threadably engageable with the body 26, a nozzle 30 threadably engaged in a end downstream of the body 26, and an air cap 31 installed in lower surrounding relationship with the nozzle - - and maintained on the main housing body 26 by a retaining nut 32. The nozzle body 26 has a liquid adhesive inlet port 34, a cylinder air inlet port 35, a foaming air inlet port. / atomization 36, and a ventilation air inlet port 38. The liquid adhesive supplied to the inlet port 34 from an appropriate supply line 40 (Figures 4, number 7 and 11) communicates with a central longitudinal passage 41 in the nozzle 30, and in turn, with a liquid flow passage 42 in the nozzle 30 prior to discharge through a foam discharge port 44 in the air cap 31 (Figures numbers 5 and 6). The nozzle flow passage 42, in this case, is defined with an upstream cylindrical inlet section 45, a tapered inlet and valve seating section 46, a small diameter nozzle section 48, and a mixing chamber of large diameter downstream 49 (Figures 5 and 6). To control the discharge of the liquid adhesive from the spray gun 20, a valve needle 50 extends coaxially through the housing body 26 to achieve a reciprocal movement between a seated clutch valve closing position with the tapered inlet section 46 of the nozzle passage 42 and the open valve position not seated. The valve needle 50, in this case, has a tapered seating section, preferably formed by two conical transverse cuts which define a sealing edge 51 engageable with the tapered inlet section 46 of the nozzle 30, and a portion thereof. of axially extended cleaning tip 52 which is placed within the nozzle section 48 of the valve passage 42 when in a closed position to maintain the free passage of adhesive formation during use. To operate the valve needle 15, as is known in the art and described in more detail in the U.S. Patent. No. 6,776,360 assigned to Spraymg Systems Company, one of the co-assignees of the present application, the disclosure of which is incorporated herein by reference, the valve needle 50 has a piston assembly 53 at an upstream end which is inclined in a valve closing direction by a compression spring 54 interposed between the piston assembly 53 and the upstream housing cover 28. The piston assembly 53 includes a piston-head portion 55 and a sealing ring in the shape of a piston. elastic annular washer 55a in sealing clutch with a cylindrical hole 56 in housing body 26. Compression spring 54 tips piston assembly 53, and therefore valve needle 50, forward to a fully seated position, that is, closed valve, shown graphically in Figure 5. The valve needle 50 is axially movable in the opposite direction (to the right in Figure 5) against the force of the spring 54 by pressurized air (hereinafter "cylinder air") selectively directed toward the cylinder air inlet port 35 from the pressurized air supply line 58 (Figures 4, 11, 12) which is communicates via the housing body 26 with an air chamber 57 on the downstream side of the piston assembly 53. To carry out the invention, the nozzle mixing chamber 49 is designed to improve the atomization and foaming of the adhesive liquid. in the spray gun to generate a fine bubble foam that can be discharged onto the moving substrate 11 in a controlled manner for effective adhesion of laminated sheets of sheet material without undesirable purges in the substrate. To this end, the mixing chamber 49 of the nozzle 30 includes an outwardly tapered pressurized air interaction section 60 which communicates between the nozzle section 48 and a downstream cylindrical expansion chamber 61 (Figure 5A). To direct the pressurized air to the pressurized air interaction section tapered outwardly 60, the nozzle 30 is formed with a plurality of radial airs 62 communicating through the tapered side wall surface of the air interaction section 60 in a position adjacent to the downstream end of the nozzle passage section 48. The steps radial air 62, which in this case are placed with a circumferential spacing of 90 ° to each other, communicate with an annular air chamber 64 defined between the nozzle 30 and the air cover 31, which in turn communicates with the foaming / atomizing air inlet port 36 through a passage 65 in the nozzle body 26. The nozzle 30 and the air cap 31 have tapered surfaces 66 in contact relation with each other around the discharge orifice of air cap foam 44, and to facilitate a tight connection, a suitable O-type gasket can be provided on an inner side of that joint. The nozzle expansion chamber 61 preferably has a diameter of at least three times the diameter of the nozzle passage section 48 and at least twice the diameter of the air cap foam discharge hole 44. More preferably, the chamber of expansion 61 has a diameter of approximately five times the diameter of the nozzle passage section 48, and the air cover foam discharge port 44 has a diameter of approximately twice the diameter - of the nozzle passage section 48. Although the theory of operation is not fully understood, it is considered that the intersection of the air inlet passages 62 with the tapered air interaction section 60 of the nozzle 30 creates a relatively large orifice area in close proximity to the nozzle section 48 in such a way that the liquid entering the interaction section 60 can not escape the effect of the incoming pressurized air currents Such as closely following the wall surfaces of the flow passage of the liquid 42. Thus, it has been found that when the liquid adhesive is directed through the nozzle 30, the plurality of spaced radial atomization air streams. circumferentially directed towards the taper air interaction section 60 effect through the agitation, atomization, and foaming with fine bubbles of the adhesive, which from there is expanded towards the expansion chamber 61 before further atomization of the foam by air Pressurized as the foam is emitted from the discharges through the relatively smaller diameter air cap foam discharge orifice 44. For forming and directing the foam in a flat ventilation spray pattern for a wider lateral application on the moving substrate 11, each spray gun 20 is operable to impact pressurized air - - (i.e., "ventilation air") at opposite costs, after discharge from the air cover discharge port 44. In the illustrated embodiment, the pressurized air communicates with the ventilation air inlet port 38 of the pressurizing gun from a pressurized air supply line 67 (Figures 4, 11, 12), which in turn is communicated by the nozzle body 26 with an annular chamber 68 defined between the axial ends of the nozzle body 26 and the air cap 31. The annular chamber 68 communicates pressurized air to a pair of longitudinal passages 69, which on Monday in opposite angled discharge passages 69a (Figure 5) directing direct streams of pressurized air at an acute angle on opposite sides of the discharge liquid adhesive foam to disperse the foam on a relatively flat narrow spray pattern transverse to the direction of movement of the substrate on which it is directed. It will be noted that the width of the flat ventilation spray, and therefore the width of the application zone on the substrate can be controlled by the pressure of the ventilation air. Referring to Figures 6 and 6A, an alternative embodiment of a spray gun that can be used in the illustrated liquid adhesive dispensing system is shown, where elements similar to those described above receive similar reference numbers. The spray gun, in this case, has an alternative form of spray nozzle design which uses an internal / external air blending technique to generate and atomize liquid adhesive foam with fine bubbles. The spray gun 20 again comprises a housing body 26, a nozzle 30 that threadably engages a discharge in the body 26, and an air cap 31 positioned in surrounding relationship with the nozzle 30 and maintained on the housing body 26 by a retaining nut 32. The nozzle 30, in this case, has a forwardly extending peak portion 33 of relatively small diameter to which it defines a liquid discharge port 33a in coaxial relationship with the cover foam discharge port. of air 44. The nozzle 30 and the air cap 31, in this case, define the foaming / atomizing air passages 37 communicating between an annular air supply chamber 37a, which in turn communicates with the foaming / atomizing air supply passage 65. In order to carry out the invention, the nozzle peak portion 33 is placed in recessed relation with the air cap discharge port 44 to define A mixing and atomizing chamber 43 is of liquid adhesive immediately downstream of the nozzle discharge orifice 33a adapted for foam and effectively atomizes the flow stream of liquid adhesive both before and incidentally to the unloading of the spraying gun. For this purpose, in the illustrated embodiment, the downstream end of the nozzle peak portion 33 is embedded a distance d from the downstream side of the air cap hole 44 to define a mixing chamber 47 immediately around the running end. down the nozzle peak portion 33. The nozzle peak portion 33 preferably has an outside diameter dJL slightly smaller than the diameter d2 of the air cover discharge port 44, and the downstream end of the peak portion 33 extends a relatively small distance d_3 toward the orifice of air cap 44. The downstream end of the nozzle peak portion defines a well-defined annular corner, which together with an annular corner well defined by an inner edge of the air cap hole 44, defines an angled passage 63 communicating with the mixing chamber 47. In practice, it has been unexpectedly discovered that the angled passage 63 defined between the well-defined corners of the nozzle peak portion 33 and an air cap discharge port 44 create streams of - swirl and turbulence in the pressurized air directed towards the mixing chamber 47, which also improves the foaming and atomization of the liquid adhesive within the mixing chamber 47 prior to discharge from the spray gun. It has also been found that turbulence more effectively maintains discharge orifices 33a, 44 of the nozzle and free air cap of significant formation which could impede efficient performance. The recessed distance d of the nozzle peak portion 33 from the downstream side of the air cap discharge port 44 is preferably smaller than the diameter "d4" of the liquid discharge port of the peak portion 33a. In practice, good operating results have been obtained when the diameter d4 of the liquid discharge port 33a is 0.025 inches (0.635 mm), the recessed distance d of the nozzle peak portion from the air cap end face is 0.013 inches (0.33 mm), the distance di is 0.05 inches (1.27 mm), the distance d.2 is 0.067 inches (1.7 cm), the distance d3 is 0.001 inches (0.025 mm), and the distance d5 is 0.008 inches (0.203 cm). The supply of liquid adhesive 14, in this case, includes a closed pressure vessel 70 (Figures 7 and 11) in which liquid adhesive is pumped from an appropriate source of supply through the inlet supply line 71 having a control valve 72, and exits by a supply line 74 that is communicated from near the bottom of the pressure vessel 70. The vessel 70 is pressurized by a pressurized air supply line 75 that communicates with the air source budgeted for. or control of a pressure regulator 76. In order to automatically maintain a level of liquid adhesive in the illustrated pressure vessel 70, a level sensor 78 of a known type is provided which includes a level 79 monitoring float. When the level of liquid adhesive descends from a certain level, the fill control valve 72 can be activated in response to a signal from sensor 78 to cause additional pumping of liquid to the container 70. When the liquid adhesive reaches a predetermined rising level, the level sensor 78 will cause the valve 72 to close. A wide variety of liquid waste can be used with the adhesive distribution system of the present invention, including water-based liquid adhesives written in the EU Application No. 10 / 654,335 filed September 5, 2003, assigned to the H. B. Fuller Company, one of the co-assignees of the present invention, the disclosure of which is incorporated herein by reference. Representative compositions of aqueous adhesives may include one or more monomeric, oligomeric and / or polymeric, dispersed, suspended, emulsified, dissolved components, to the like, in an aqueous medium. The adhesive composition can include at least one resin that is water soluble or dispersible in water at a temperature in the range of from about 20 ° C to about 90 ° C. A wide variety of different resins and / or monomeric ingredients thereof can be used. Representative examples of suitable resin hypo include one or more of acrylic, styrene-acrylic, styrene-butadiene, vmyl acetate, polyvinyl alcohol, urethane, chloroprene, phenolic, polyamide, polyether, polyesters, polysaccharides (including starch, dextna , cellulose, gums, or the like), combinations of these, and the like. Particularly useful resins are acrylic, vinyl acetate, polyvinyl alcohol, dextna, starch, and the like. The composition can be supplied as a solution, latex, emulsion, dispersion, or the like. In addition to the monomeric reams and ingredients, the adhesive compositions may include lubricants, emollients, rheology modifying agents, anti-vaporization additives, fillers, extenders, foaming agents., or similar. Examples of adhesive compositions include the following: 1. A part of Laponite RDS is dispersed in water for 20 minutes; 20 parts of a low molecular weight polyvinyl alcohol resin (Celvol 205) are added and mixed until a smooth mixture is obtained. The mixture is then heated to 190-200 ° F (87.7-93.3 ° C) for 30 minutes or gentle agitation. The solution is then cooled to 100-120 and a biocide is added and the viscosity is adjusted between 250-300 cP at room temperature (72 ° F = 22.2 ° C). The resulting composition can be used in the illustrated distribution system to produce a bead foam or fine bubbles to more effectively join the layers of multi-sheet fabric and the like. 2. A product obtained from the polymerization of vmilo acetate monomer (30 parts) in an aqueous solution of dextpna (40 parts dextnna and 30 parts water) is diluted to a viscosity range of 350 to 300 cP in 72F (22.2 ° C), to deliver a solution containing approximately 50% solids. Then, a solution diluted in a fine bubble foam can be generated by the illustrated dispensing system to effectively bond the sheet material of laminates.

- - So far as indicated above, it has not been difficult to generate finely atomized suitable foams from liquid adhesives, but even the most difficult thing is to control the uniform application of the foam on a mobile substrate during the start-up operations in which the Movement of a substrate is accelerated and during changes in process conditions. In addition, when pressurized air atomization has been used to assist atomization and foaming of the adhesive, changes in air atomization pressure create changes in the back pressure towards the liquid supply which may prevent the supply of the liquid from affecting the liquid. the desired density and conformation of the foam, and inhibit reliable process control. According to an important aspect of the invention, the liquid adhesive supply control system 15 is operable to generate and distribute foam with the desired properties during a full range of operation of the dispensing machine, as well as during the ignition of the machine and the changes in the processing parameters, including changes in the atomization pressures of the liquid and / or air. For this purpose, the liquid distribution system includes a plurality of positive displacement pumps 80 each of which is dedicated to a respective spray gun 20 for directing predetermined amounts and measurements of the liquid to the spray guns 20 for consistent application and uniform on a moving substrate 11, notwithstanding changes in processing speeds or conditions. The illustrated positive displacement pumps 80 are gear-type pumps each comprising a pair of constant-take gear 81, one of which is driven mechanically by a conductor 82. (Figures 7 and 7A). As is known in the art, as one of the gears 81 is driven, the two gears rotate and mesh to force a specific amount of the liquid from the inlet to the outlet of the pump 80 positively during each revolution. of the gears. Such positive displacement gear pumps are commercially available, such as the Bro n & Sharp Model 700 Series offered by BSM Pump Corporation, North Kmgstown, Rhode Island. It has been discovered that such positive displacement pumps 80 act effectively with a liquid measuring device for each spray gun 20 so that the supply of liquid adhesive to the spray guns 20 can be precisely controlled and changed through the control of the spray gun. the operating speed of the pumps 80. It will be understood that although the gear pumps are described in the illustrated embodiment, other types of positive displacement pumps may be used in the liquid adhesive delivery system, such as displacement pumps of progressive quality. a known guy. In carrying out the invention, the positive displacement pumps 80 in the illustrated embodiment are driven from a common energy source such that the pumps 80 uniformly send similar amounts of liquid adhesive to the respective spray guns 20. In the embodiment illustrated , as graphically depicted in Figures 8-10, the pumps are installed on a frame 85 and are driven by a common drive motor 86, such as a selectively controllable variable frequency drive motor of a conventional type. The illustrated frame 85 has a rectangular construction which supports a first plurality of pumps 80 in a first row along the lower part of the frame 85 and a second plurality of pumps 80 in a second row along the upper part of the frame. frame 85. The driving axes 82 of each pump 80 carry a respective drive input wheel 88, and the drive motor 86, in this case, has a gearbox 89 - with an output driver 90 carrying a pair of drive wheels. One of the sprockets of the drive motor is operably coupled to and drives the first row of pumps 80 by a first band or worm 94 prepared around the sprockets 88 for the pumps 80 in the first row and the sprockets 95. Another gear wheel of the drive motor engages and drives the pumps 80 of the second row through a band or chain 96 prepared around the drive sprockets 88 for the pumps 80 of the second row and the drive sprockets 98. therefore, the selected operation of the drive motor 86 will simultaneously operate the positive displacement pumps 80 of both rows, causing the pumps 80 to direct substantially similar amounts of adhesive to the respective spray guns 20 based on the operating speed of the pumps 80. Although the common drive for multiplicity provides savings in the design and manufacture of the system As a distribution, it will be alternatively understood that individual drive motors can be used to allow independent flow control for each spray gun. In carrying out this additional aspect of the invention, the liquid supply control system - - is operable to control the speed of the positive displacement pumps, and therefore, the amount of the adhesive liquid directed to the spray guns 20, proportional to the speed of the moving substrate 11 such that a constant amount of adhesive can be applied. to the substrate with a total range of operable tissue speeds. For this purpose, the delivery control system 15 includes a tachometer 99 of a known type for detecting the speed of the mobile substrate 11 and a main controller 100 for the distribution system responsive to the signals coming from the tachometer 99 to proportionally control the speed operation of positive displacement pumps 80. Therefore, it can be seen that the desired adhesive application rate can be set in the controller either before or during operation, and the supply control system 15 automatically compensates for changes in speed of the line by adjusting the operating speed of the pumps 80. Therefore, a preprogrammed foam application rate can be established in the controller 100 and the system will automatically start spraying at the programmed rate. During the increase, this rate will be maintained up through the maximum operating speed without additional operator intervention. In addition, since positive displacement pumps 80 effectively measure liquid delivery, the application rate is not affected by other changes in processing parameters, including changes in atomization air pressure, as it will become apparent. Although the positive displacement pumps 80, and particularly the illustrated gear pumps, function as efficient liquid measurement devices, it has been found that high differential pressure formation in the pumps can result in the liquid being forced under pressure through of the pumps by virtue of the manufacturing tolerance between the gears and the pump housings. This phenomenon, sometimes referred to as liquid slip, can increase the processing and transfer performance affected by the rotating operation of the gears and can alter the uniformity of the foam generated. In carrying out the invention, in order to prevent liquid slipping through the pumps 80 and to improve reliable control in the supply of liquid adhesive to the spray guns 20, the supply control system 15 is operable to balance the inlet and outlet pressures for each of the positive displacement pumps 80 in order to prevent pressure induced fluid sliding through the pumps. For this purpose, in the illustrated embodiment, a nozzle pressure transmitter 104 is provided on the outlet line 40 of each pump 80 (in this case, the inlet line 40 to each spray gun 20) and a multiple pressure transmitter 105 in a manifold supply line 106 and feeds the inlets to each of the pumps 80 (Figure 11). In a typical operation of the distribution system, for a programmed operating speed for the pumps 80, the nozzle pressure transmitter 104 will detect a pressure in the output line according to the magnitude of the programmed flow. When the manifold pressure transmitter 105 detects a different pressure, the air regulator 76 to the liquid supply pressure vessel 70 is operated by a pneumatic pilot signal from an I / P converter 107 under control of the controller 100 so as to adjust the pressure in the pressure vessel 70, and therefore, the liquid pressure in the manifold line 106 in order to equalize the inlet and outlet pressures through the pumps 80. By adhering to a further feature of the invention , the foaming / atomizing air and the ventilation air to the spray guns 20 can also be selectively controlled to generate and apply foam to the desired characteristics. To control the foaming / atomizing air, is provided to air regulator and foaming / atomization 110 in a foam / atomization air manifold line 111 which communicates with each of the spray guns 20 and which can be controlled by an I / P converter 112 by the controller 100. The venting vent is communicated to each of the spray guns 20 through the venting supply line 67, whose pressure is controlled by a venting air regulator 114 through an I / P converter 115. Preferably, through the programming of the controller 100, a uniform density of the foam can be achieved by automatically increasing the foaming / etomizing air pressure by providing the operative velocity of the positive displacement pumps 80. Alternatively, both the eire of foaming / etomization as the air of ventilation can be controlled selectively by the controller 100 regardless of the magnitude s of the flow of liquid adhesive stops a perticular epliceción. This may be particularly desirable when there is a need to increase the concentration of the adhesive, such as the start to end of a roll web. This can be reduced by reducing the foam pressure / etomization, which will reduce atomization and allow a more concentrated liquid adhesive to be applied. If similar, reducing the air pressure of ventilation will result in a closer and more concentrated adhesive eplication. From the foregoing, it can be seen that the liquid adhesive supply control system 15 is effective in enabling precise control of both the adhesive delivery rate and the foam characteristics on a wide range of operable line velocities. In a typical operation of the liquid distribution system 10, the sustrete 11 can move at line speeds of up to 2500 feet per minute (762 m / min) with consistent foam characteristics and uniform adhesive application theses. The sizes of the adhesive may vary between approximately 15 and 200 mg / ft2 depending on the desired bond strength. The foaming / etomizing air pressure may preferably be between 10-20 psi, with venting pressures of 10 psi or less. The spray guns can be positioned between 6-12 inches (15.2 cm-30.5 cm) from the moving tissue and distribute foam with transverse widths of approximately 5 to 6 inches (12.7-15.2 cm). The foaming / atomizing air generates an edhesive foam with the nozzles, as described above, which is atomized edically and measures the pressurized discharge of the nozzles. The foaming with fine bubbles of the edible and its atomizededecrease substantially eliminates purging in highly porous substrate fabric materials. The froth can have average bubble sizes of 100 microns or less, depending on the particular application and drying requirements. By the proper control of the ventilation air, the system is opeable for ephedrine edginess in the hanger of the bands or a cover 100%. The strength of the fabric veneer and other characteristics of the fabric are also measured, such as manual sensation, softness, comfort, cadence, definition of reelzedo, volummosided, ebsorbency, color. In accordance with a feature of an edition of the invention, an automatically operable cleaning system is provided for cleaning the exterior and interior surfaces of the spray pistols 20. In the illustrated embodiment, the pulverizedore header housing 24 has a cover 120 which It is placed normally in the open position, as shown graphically in Figure 2, during the operations of distribution of the adhesive. In order to initiate a cleaning operation, the controller 100 or of progressing to activate an air cylinder 121 from which causes the cover 120 to rotate to a closed position., as graphically represented in Figure 3, including the spray guns 20 inside the housing 24 so that all the sprays and the purge water are ceptured. In order to clean the external surfaces of the spray pistols 20, the alloy cover 120 serves as a primer for two rows of egua 122 spray nozzles, which can be conventional full-peak spray nozzles, with pairs of the nozzles 122 being constructed and ends of the pistol pulverizers 20 respectively when closing it covers 120. Through the activation of a flow valve operede by air 123 the water can be directed to an ague manifold line 124, which in turn communicates with them. external egue spray nozzles 122 (Figures 3 and 12). The retention valves, designated CK in Figure 12, are provided in the supply lines of the water supply to prevent a backflow and drip. In order to carry out the internal cleaning of the spray pistols, or again by automatic means of controlling the controller 100, a control valve of the supply line of the adhesive 126 is first closed and an adhesive purge valve 128 is emitted to allow the purge of the liquid adhesive in the liquid supply lines. The activation of the control valve 130 and a purge line of 131 allows the communication of the purge fluid from the liquid dioxide manifold 132 and the liquid weights of the respective spray pistols 20. In addition, the activation of the control vents 135 will effect the transmission of a supply of water from the line 136 through the foaming air / aeomizetion and the ventilation vents 111, 67 respectively, to clean the foaming air. atomizecion and venting air passages of spray guns 20. The retention valves, designated nine "CK" in Figures 5 and 12, are provided to prevent air from entering the egua supply lines and to enter water into the air supply lines. During a cleaning cycle purge water is captured within the housing 24, the collar preferably has sufficient seperation to allow the graded to carry the purge water to a drain drain 129 (Figure 3). In order to prevent the escape of purge water during a cleaning cycle, the cover 120 and the main housing 24 have a double-skin construction and allow the interior and exterior panels 120a, 120b of the cover and the interior and exterior panels to be installed. 24e, 24b of elojemiento to prevent the escape of the purge egue without need of flexible seals or a precision inter-clutch of the cover and housing.

- Referring to Figure 13, there is shown a liquid liquid supply control system which can be used in connection with the liquid adhesive delivery system of the present invention, where the liquid flow is measured and compared with a theoretical value for compensate and avoid the liquid displacement and trevés of positive displacement pumps. Again, elements similar to those described above have a similar number of references. In this case, liquid fluid is poured into a pressure port 140 of a flow meter 141. The tissue velocity is detected by a tachometer 99 and the positive deployment pump 80 is operated by the controller 100 and a velocity is attained. provide the necessary supply of the necessary adhesive to the spray gun 20. The pressure transmitters 104, 105 detect the pressure difference in the pump 80 and control the inlet pressure to the pump 80 by an automatic liquid regulator 142 in order to control and minimize the sliding of liquid in the pump 80. The flow rate of the liquid ectuel, measured by the flow meter 141, is compared by the controller 100 with a magnitude of the flow theory and the velocity of the pump 80 is adjusted compensate for any differences between the magnitude of the flow theorize and the magnitude of the flow ectuel. Regulators eutomatic pressure eire - 110, 114 control the foaming / atomization and venting pressures of the spray gun 20. As described by enteporided, the individual bombs 80 provide adhesive to the conventional spray gun 20 and the foaming / atomizing and spray ports. ventilation air 144, 145 respectively supply the special spray guns. The eire regulators are supplied by a common eire supply line and the control signals from the regulators 110, 114 and 142 are supplied by current and pressure converters. From the foregoing, it can be seen that the adhesive distribution system of the present invention is found to more uniformly liquid adhesives on mobile substrates, notwithstanding changes in line speed, adhesive liquid flow magnitudes, or in the pressures of air ethomization. The liquid distribution system is efficient to generate and eplicer a liquid based water based foaming emulsion so as to increase the adhesive bonds of the laminated humps, facilitating faster drying, and minimizing the damage of the purge through the sustreto. . The distribution system of liquid plastic is relevently economical in its construction and is ready for efficient control. In addition, the system includes a system of cleaning eutomaticemente opereble for easy maintenance.

Claims (15)

1. NOVELTY OF THE INVENTION The invention having been described as an artifact, the contents of the following claims are reclassified as property: CLAIMS 1. A liquid adhesive distribution system for distributing liquid adhesive on a mobile substrate, characterized in that it comprises: a cebecere having at least one spray pistol, a supply of liquid adhesive, a supply of pre-set air, the spray gun having a Liquid inlet attaches the supply of liquid plastic to receive the liquid plastic from the supply of liquid plastic and attaches a spray nozzle to distribute the liquid adhesive coming from the spray pistol on the mobile suppository, the spray pistol having a foaming air inlet. Entanglement coupled to the pressurized air supply to receive the presumed air and direct the pressurized air to the generator to connect a foam of liquid adhesive to distribute on the mobile substrate, and - a positively displaceable velocity positive displacement pump supply of liquid adhesive and the spray gun to direct a measured centimeter of liquid adhesive to the spray gun providing the ope- ratial speed of the positive displacement pump.
2. 2. A system of distribution of liquid film to distribute liquid film on a mobile substrate, because it comprises: a cement strip having the least pistol pulverizer, a supply of liquid film, a supply of pressurized air, having the spray gun in between of liquid ecoplede the supply of liquid adhesive to receive the liquid adhesive from the supply of liquid adhesive and a spray nozzle to distribute the liquid adhesive coming from the spray gun on the mobile suppository, having the spray gun between the foaming eire / etomizeción Ecoplex the pressurized air supply to receive pressurized air and direct the pressurized air to the spray nozzle to generate a foam of liquid adhesive to distribute on the mobile substrate, a positively deployable pump of velocided veriebly selectively operetive ecoplated between the s uministro of liquid adhesive and the spray gun pere direct a centided medide of liquid adhesive and the proportional pulverizing pistol; and a control to control the pressure of the etomizetion air supplied to the pistol pulverizer in relation to the operative speed of the menere tel distribution pump that is generated by a uniformly suspending foam by the spray gun regardless of the speed of the pumping inside. of an operative rengo.
3. 3. The liquid distribution system according to claims 1 or 2, characterized in that it includes a sensor for detecting the movement of the suppressor, and an operable control to control the operative velocity of the positive deployment pump with relegation at the rate of detected movement of the substrate.
4. 4. The liquid distribution system according to claim 3, characterized in that the head includes a plurality of spray pistols, each spray gun having a liquid supply line with a positive displacement pump respectively for directing a measured amount of liquid and liquid detergent. le pistóle pulverizedore respective proporcionel e tesa de - movement of the sustreto.
5. 5. The liquid adhesive dispensing system according to claim 1 or 2, characterized in that the positive release pump has a liquid supply line coupled to the supply of liquid adhesive and a line of salidon-echoed to the spray gun, a first sensor to replace the liquid adhesive. Detecter the pressure of liquid in the line of exit, to second sensor stop detecter the pressure of liquid in the line of entrance, and an operable control in response to the sensors that detect a difference in the pressure of the liquid in the lines of interdeparting and selide to adjust the pressure of the liquid adhesive supplied and the line of penetration to prevent the liquid pressures in the input lines. and departure. The liquid adhesive distribution system according to claims 1 or 2, characterized in that the positive displacement pump is a gear pump having a liquid inlet and a liquid cartridge, and the gear pump having a gear wheel. Rotary-gear gears are operable to direct a predetermined amount of liquid through the pump during each revolution of the pump. The liquid distribution system according to claims 1 or 2, characterized in that the spray gun includes a nozzle body having a liquid flow weight that communicates with the fluid source, the nozzle having a flow path of liquid that is communicated with the body flow weight, including the nozzle liquid flow weight a reletively small diameter nozzle section and joins a diameter mixer more than the current stream, and having the spray pistol a weight of eire of etomization that is communicated between the atomizing air inlet with the nozzle mixing chamber in such a way that the pressurized air directed to the spray pistol is mixed, etomized, and creates a foam of liquid adhesive that passes through the nozzle before of the discharge of the nozzle. 8. The liquid distribution system according to claim 7, characterized in that the spray pistol includes an eire tape installed in circumferential relation with a nozzle end of the nozzle, defining the eire tape and nozzle a pressurized air chamber that It is communicated with the preparation of aeomizetion air, including the nozzle mixing chamber, a section of interaction of eire ehusada hecie efuere that communicates with the section of weight of nozzle and a section of cylindrical expansion abe or communicating with the section of air interaction, and having the nozzle of a plurelided of weights of entrere-de eire especdos circunferencie that communicate with a pered leterel ejadaada of the section of passage of interaction of air to direct a plurality of currents of eire presurizede Make the section of air interaction in trensversel relegation with the liquid adhesive that is descending from the secc nozzle ion. 9. The spray nozzle assembly according to claim 8, characterized in that the weights of the trensverseles radially shared with the weight section of air circulation interaction at a running end of the nozzle weight section, having the pressure chamber a diameter of at least three times the diameter of the nozzle weight section, and the nozzle expansion chamber having a diameter of at least twice the diameter of the eire foam foaming discharge orifice. 10. The liquid film dispensing system according to claim 1 or 2, characterized in that the spray pistol includes a body having a liquid flow passage communicating with the liquid inlet, a nozzle having a liquid flow passage that communicates with the body flow passage, and having the nozzle a relatively small peak portion of diameter from a running end thereof, the neck defines a liquid desiccation orifice, an air cap installed in surrounding relation thereto. nozzle and having a central desiccation hole aligned coaxially with the nozzle peak portion, and placing the recess portion in a recessed recess with a running end ebech of the air stripper orifice to define a mixing chamber within the cap. of air, and defining an air gap and the nozzle a foaming / etomizing air passage that communicates between the air supply presu and the chamber of the mixer to foam and atomize the liquid from the incident way of descending it from the nozzle and the air discharge holes. 11. The liquid distribution system according to claim 10, characterized in that the peak portion has a smaller diameter than the diameter of the discharge hole of eirepe de eire, and the nozzle peak portion and the eire cap discharge hole have well-defined annular flanks which define a step for Communicate the foaming / atomizing air to the mixing chamber. 12. The liquid adhesive dispensing system according to claim 1 or 2, characterized in that it includes a supply of agüe selectively connectable to the spray pistol to direct a purge water through the spray pistol to clean the internal passages of the spray gun. spraying gun during a cleaning cycle, including the end cap, a housing for the purge directed through the spraying gun, including the elocution a selectively closable cover, carrying the cover at least one nozzle of ague connectable the supply of oil direct the egue on and clean the outer surfaces of the spray gun, and being selectively mobile cover it between an open position that allows the direction of the liquid adhesive from the spray gun on the mobile subtlety and unites the closed position in the cover. accommodation and orientates the pulveri nozzle Aging in the direction of the spray gun. 13. The liquid distribution system, according to claims 1 or 2, characterized in that it includes a control to control the operating speed of the positive displacement pump, a liquid flow meter to measure the flow rate of the liquid in order to pump from the liquid supply, with the operating control to compare the flow quantity of the measured liquid with a measurement of the theoretical gas and adjust the velocity of the positive displacement pump in order to compensate the differences between the theoretical flow and the megnitude of the current flow. - - 14. A method for distributing a liquid film on a mobile substrate characterized in that it comprises the steps to provide a supply of liquid film, directing the measured sizes of the liquid film from the supply of liquid plastic, and a plurality of spray pistols to distribute over the mobile substrate, direct the pressurized atomizing air of the spray guns to mix with the liquid adhesive of menere tel that generates an adhesive foam and distributes it over the mobile substrate, control the measured supply of the liquid substrate and the sprayed pistols in relation to the velocity of Menere Tel sustreto movement that distributes uniform uniformity of adhesive on the substrate regardless of the speed of movement of the substrate within an operating range. 15. The method according to claim 14, characterized in that it includes directing a measured supply of liquid substituate to each spray gun by means of a respective positively operetive positively deployable pump, monitoring the velocity of the moving substrate and controlling the operating velocities of the positive deployment pumps. in relation to the sensing velocity of the squeeze movement, and controlling the pressure of the etomization emitted to the pistol-sprayers with relegation to the operative velocity of the menere positive deployment pumps such that a liquid adhesive substantially uniformly foamed is distributed about the mobile suburb within an operational hierarchy. - SUMMARY An operable liquid adhesive distribution system to more uniformly apply liquid foam on mobile substrates, do not obscure changes in line velocity, liquid flow velocities, or foam / spray eire pressures. The liquid adhesive system illustrated includes a head having a plurality of eire atomizing spray guns; having a reciprocating pump of variable velocity positive deployment deployed to direct a measured quantity of liquid plastic from a supply of liquid plastic and the respective spray pistol; and a control to control the operative velocity of the positive deployment pumps with relegation to the velocity of the moving substrate and the foaming air pressure / etomizetion of the spray pistols in relation to the operating speed of the positive deployment pumps. The control is also operable to monitor pressures through the positive deployment cylinders to ensure the precise direction of medium-sized liquid centers with pistol pulverizers. The spray pistols are designed for improved foaming and atomization of the liquid adhesive, and the header is convertible into a cerrede eficez hous ing structure for housing cleaning and purging liquids during an automatically operable cleaning cycle.