Dispensing system, nozzle and method for independently dispensing and controlling liquid

Abstract

A dispensing system comprising first and second valve modules each having an output for delivering a liquid under pressure, a nozzle assembly coupled to the first and second valve modules, the nozzle assembly having at least two separated, at least partially coextensive outputs respectively communicating independently with the outputs of the first and second valve modules. A nozzle assembly adapted to be coupled to first and second valve modules each having an output for delivering a liquid under pressure, the nozzle assembly having two liquid inputs and at least two separated, at least partially coextensive outputs respectively communicating independently with the two liquid inputs, and the two liquid inputs adapted to be coupled in communication with the outputs of the first and second valve modules. A method of extruding a liquid, comprising delivering the liquid to two separated, at least partially coextensive outputs of a nozzle assembly, discharging the liquid from the outputs, and combining the discharged liquid on a substrate.

Description

FIELD OF THE INVENTION

[0002] The present invention generally relates to extruding liquids and, more specifically, to extruding liquids from a slot nozzle.

BACKGROUND OF THE INVENTION

[0003] Currently, various manufacturing operations require the extrusion of thermoplastic liquids, such as hot melt adhesives, from slot-shaped openings in nozzles. For example, it may be desirable to lay down a thin film of adhesive on a moving substrate, such as a nonwoven material. The thin film of adhesive may have any desired width but, for example, one application requires a total width of 150 mm. In addition, it may also be desirable to have different add-on weights of adhesive along the length of the substrate as the substrate moves adjacent to the dispenser during the manufacturing operation. In one current design, a shim plate construction is used which includes three adjacent 50 mm slots to achieve a total dispensed adhesive width of 150 mm. Each 50 mm slot is fed by two separate on/off valve modules which receive pressurized liquid adhesive from two separate pumps. For example, a system such as the one disclosed in U.S. Pat. No. 6,422,428 may be used in this situation. The disclosure of U.S. Pat. No. 6,422,428 is hereby incorporated by reference herein. The difference between the system disclosed in U.S. Pat. No. 6,422,428 and the slot coating system just described is that a slot coating nozzle assembly extends across multiple valve modules as opposed to having a separate nozzle coupled to each module as shown in the patent.

[0004] In the current slot coating system, to achieve different add-on weights along the length of the dispensed film, one of the two valve modules feeding a 50 mm slot is cycled off and then on again. The other valve module feeding that slot remains on. While one of the two valve modules is off, a lesser amount of liquid should theoretically flow to the 50 mm slot and be discharged. This system, however, did not produce the desired results in that the patterns produced were not controllable in an acceptable manner and with the accuracy of the desired controllable and variable add-on weight of adhesive along the length of the substrate.

[0005] For these reasons, as well as others, it would be desirable to provide a dispensing system which allows accurate, individually metered output capability from a single extrusion location on a dispensing system.

SUMMARY OF INVENTION

[0006] The present invention generally provides a nozzle assembly adapted to be coupled to first and second valve modules which each have an output for delivering a liquid under pressure. The nozzle assembly includes two liquid inputs and at least two separated, at least partially coextensive outputs, which may be slots or other types of liquid outputs, respectively communicating independently with the two liquid inputs. The two liquid inputs are adapted to be coupled in communication with the outputs of the first and second valve modules.

[0007] A dispensing system is provided which includes the nozzle assembly described above, as well as at least first and second valve modules and, preferably, first and second pumps respectively coupled to the first and second valve modules for supplying the liquid independently to each valve module.

[0008] A method of extruding a liquid is provided comprising delivering the liquid to two separated, at least partially coextensive outputs of a nozzle assembly, discharging the liquid from the outputs, and combining the discharged liquid on a substrate. Also in accordance with the method, the discharge of liquid from each output may be separately controlled to vary the amount of liquid dispensed onto the substrate. This may be achieved, for example, by cycling one of the first and second valve modules on and off.

[0009] Benefits are achieved by the invention such as improved metering capability and improved, accurate add-on weight variability along the length of a dispensed liquid pattern. These and other objectives, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following description of one preferred embodiment of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a disassembled perspective view of a nozzle assembly constructed in accordance with the preferred embodiment of the invention.

[0011] FIG. 2 is an assembled perspective view of the nozzle assembly shown in FIG. 1, and schematically illustrating coupling thereof to respective pumps and valve modules.

[0012] FIG. 3A is a cross sectional view taken along line 3A-3A of FIGS. 2, 5 and 6.

[0013] FIG. 3B is a cross sectional view taken along line 3B-3B of FIGS. 2, 5 and 6.

[0014] FIG. 4 is an enlarged cross sectional view of the output portion of the nozzle shown in FIG. 3A.

[0015] FIG. 5 is an elevational view of a mouthpiece adaptor portion of the nozzle assembly shown in FIG. 1.

[0016] FIG. 6 is an elevational view of a mouthpiece portion of the nozzle assembly shown in FIG. 1.

DETAILED DESCRIPTION

[0017] Referring first to FIGS. 1, 2, 5 and 6, a nozzle assembly 10 of the present invention is constructed from multiple elongate pieces including a mouthpiece adaptor portion 12, three shim plates 14, 16, 18, and a mouthpiece portion 20. These pieces 12, 14, 16, 18, 20 are properly aligned using alignment pins 22, 24 extending through respective holes and fastened together using threaded fasteners 30 extending through respective holes in mouthpiece portion 20 and shims 14, 16, 18 and threaded into internally threaded holes in mouthpiece adaptor portion 12. The resulting assembly 10 is fastened to a plurality of, in this case, six valve modules 40a-f (FIG. 2) using threaded fasteners 42. Each valve module 40a-f receives liquid under pressure from a separate and independently controllable pump 44a-f and dispenses the pressurized liquid into six respective liquid input ports 46a-f in nozzle mouthpiece adaptor portion 12. The liquid output (not shown) of each valve module 40a-f is sealed to mouthpiece adaptor portion by a respective O-ring 48a-f. Each liquid input 46a-f of mouthpiece adaptor portion 12 independently communicates with a separate input slot in either mouthpiece adaptor portion 12 (two separate input slots 50b, 50e communicating respectively with liquid inputs 46b, 46e) or nozzle mouthpiece portion 20 (four separate input slots 50a, 50c, 50d, 50f respectively communicating with liquid inputs 46a, 46c, 46d, 46f through respective holes (14a, 14c, 14d, 14f), (16a, 16c, 16d, 16f), (18a, 18c, 18d, 18f) in shim plates 14, 16, 18).

[0018] Input slots 50b, 50c in nozzle mouthpiece adaptor portion 12 communicate with elongate output slots 52, 54 and also with discharge cutouts 56, 58 formed in shim plate 14. Two additional coextensive discharge cutouts 60, 62 are formed in shim plate 18 and align with cutouts 56, 58 but are separated from the coextensive cutouts 56, 58 due to the presence of central shim plate 16. The two cutouts 60, 62 in shim plate 18 are fed by elongate output slots 64, 66 fed by input slots 50a, 50f. A central cutout 68 in shim plate 18 is fed by two modules 40c, 40d and input slots 50c, 50d communicating with a single elongate output slot 70 which is coextensive with cutout 68. It will be appreciated that this central dispensing zone may also be constructed similar to the two outer zones such that separate cutouts are provided in shims 14, 18 and separated by inner shim 16, and fed by separate modules.

[0019] Using arrows to denote liquid flow, FIGS. 3A, 3B and 4 illustrate how the liquid from input ports 46e, 46f and input slots 50e, 50f feed separate slot outputs defined by coextensive cutouts 58, 62. The liquid exits nozzle assembly 10 as separate extruded films which combine on a substrate (not shown). It will be appreciated that either module 40e or 40f (FIG. 2) may be cycled on or off to likewise cycle the dispensing of liquid from either of the outputs 58, 62 on or off and thereby lower the add-on weight of liquid in the dispensed film pattern for the time period that a module is shut off. Other methods of controlling the output of liquid, such as by varying the pump speed, may also be used for similar effects. It will also be appreciated that other types of outputs and resulting liquid patterns may also be utilized in accordance with the inventive concepts. Cutouts 56, 60 similarly receive liquid from input ports 46b and 46a, respectively, and are also separated by central or inner shim 16. Likewise, they are independently controlled by modules 40b and 40a.

[0020] While the present invention has been illustrated by a description of a preferred embodiment and while this embodiment has been described in considerable detail in order to describe the best mode of practicing the invention, it is not the intention of applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the spirit and scope of the invention will readily appear to those skilled in the art. The invention itself should only be defined by the appended claims, wherein we claim:

Claims

1. A dispensing system comprising: first and second valve modules each having an output for delivering a liquid under pressure, a nozzle assembly coupled to said first and second valve modules, said nozzle assembly having at least two separated, at least partially coextensive outputs respectively communicating independently with said outputs of said first and second valve modules.

2. The dispensing system of claim 1, further comprising first and second pumps respectively coupled to said first and second valve modules for supplying the liquid independently to each valve module.

3. A nozzle assembly adapted to be coupled to first and second valve modules each having an output for delivering a liquid under pressure, said nozzle assembly having two liquid inputs and at least two separated, at least partially coextensive outputs respectively communicating independently with said two liquid inputs, and said two liquid inputs adapted to be coupled in communication with the outputs of the first and second valve modules.

4. A method of extruding a liquid, comprising delivering the liquid to two separated, at least partially coextensive outputs of a nozzle assembly, discharging the liquid from the outputs, and combining the discharged liquid on a substrate.

5. The method of claim 4, further comprising: separately controlling the discharge of liquid from each output to vary the amount of liquid on the substrate.