GB2107219A

GB2107219A - An applicator

Info

Publication number: GB2107219A
Application number: GB08129375A
Authority: GB
Inventors: John Carus Smith
Original assignee: Shirley Institute
Current assignee: Shirley Institute
Priority date: 1981-09-29
Filing date: 1981-09-29
Publication date: 1983-04-27
Also published as: GB2107219B

Abstract

An applicator for continuously applying a substance to both sides of a length of material comprises two spaced applicator rolls 1 and 2 which contact substance in respective containers of the substance 3 and 4 and between which the material passes. Substance from the containers 3 and 4 is transferred to the material by the rolls 1 and 2, the amount transferred being controlled by respective doctor blades 9 and 10. After application of the substance, the material passes to a dryer. The apparatus facilitates continuous application of substance to material in a controlled manner. <IMAGE>

Description

SPECIFICATION An applicator The present invention relates to an applicator for continuously applying a substance to both sides of a length of material.

Applicators of this general type already exist but they are either difficult to operate in practice and/or expensive to install and operate. One such known applicator comprises a bath through which the length of material is drawn. As it emerges vertically from the bath doctor blades control the thickness of the substance adhering to the material. With such a machine, it is not usually possible to vary the substance, or indeed the amount of substance applied, as between one side of the material and the other. Furthermore, the height of the building necessary to house the vertical arrangement can result in a prohibitively expensive installation.

According to the present invention, there is provided an applicator for continuously applying a substance to both sides of a length of material comprising first and second rotatable members and means for containing the substance to be applied, the arrangement being such that in operation substance may be transferred from the means for containing to the rotatable members and applied thereby to opposite sides respectively of the length of material as it passes between them.

A preferred embodiment may include any one or more of the following advantageous features:- (a) Means are provided for driving at least one of the rotatable members, (b) The means for driving comprises a drive to one of the rotatable members and a driving connection between the two members or independent variable speed drives to each member, (c) The driving connection between the two members enables them to be driven at different speeds, (d) The means for driving of (a) comprises an independent variable speed drive to each of the rotatable members, (e) The means for containing comprises two baths disposed respectively adjacent the two rotatable members so that in operation the members dip into the substance in the baths, (f) In relation to the path of approach of the length of material to the rotatable members the peripheries of the rotatable members overlap so that the direction of travel of the material is altered as it passes between the members, (g) The position of one of the rotatable members is adjustable relative to the other rotatable member, (h) The adjustable rotatable member is mounted in relation to the other rotatable member so that it can follow an arcuate path about the centre of the axis of the said other member, (i) Means are provided for limiting the thickness of substance on at least one of the rotatable members, (j) The means of (i) comprises a doctor blade or knife, (k) The means of (i) is adjustable.

In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the single figure of the accompanying drawings, in which: Figure 1 shows one form of applicator in accordance with the invention, and Figure 2 shows a possible modification of the applicator of Figure 1.

Referring to Figure 1 , the applicator comprises two rotatable members in the form of spaced applicator rolls 1 and 2. The spacing of the rolls is chosen so that roll 2 contacts the length of material as soon as possible after roll 1, but usually not so soon as to subject the material to a constriction. In some cases, however, disposing the rolls so that the material is subject to a constriction may be beneficial. Two containers 3 and 4 are disposed adjacent the rolls 1 and 2 respectively to contain substances (which may be the same or different) to be supplied to those rolls.

Container 3, which is disposed above the roll 1, is formed by side plates 5 and 6 and end plates 7 and 8 and has an open base through which the substance contained by it directly contacts roll 1.

Adjacent the side of the container 3 is a doctor blade 9 which controls the thickness of the substance layer which the roll 1 carries from the container 3 as it rotates. If desired, the doctor blade 9 may form one of the side walls of the container 3 (i.e. in place of side wall 6).

Container 4 is a bath which is disposed beneath the roll 2 and into which the roll 2 dips. There is also a doctor blade 10 adjacent roll 2 for controlling the thickness of the layer of substance carried out of the bath 4 by the roll 2. Roll 1 may be gravured for certain substances and doctor blade 10 may then be dispensed with as the thickness of the substance on the roll is determined by the depth of the engraving.

Both rolls 1 and 2 are rotatably mounted in bearings respectively diagrammatically illustrated at 11 and 12 (only one bearing per roll visible).

Roll 1 carries a pulley 1 3 which is drivably connected to a prime mover 14 (such as an electric motor) which also carries a pulley by means of an endless belt 1 5. Each roll 1, 2 is connected to a gear 16, 1 7 and these gears 16, 1 7 mesh to provide a driving connection between the rolls. Thus by operation of prime mover 14 both rolls 1 and 2 may be positively driven.

In its passage through the applicator, the elongate length of material or web W, to which the substance in containers 3 and 4 is to be applied, passes from a feed reel 1 8 via a guide roll 19 between the applicator roll 1 and 2, through a dryer 20 and via a further guide roll 21 to a drivable take up reel 22. The path that the web W follows between rolls 1 and 2 may be altered to alter the pressure applied to the web by the rolls by adjusting one or both of the rolls 1 and 2. In Figure 1 only roll 1 is adjustable and for this purpose it is mounted on a plate 23 which is itself mounted for pivotal movement about the axis of roll 2. In this way the lap of the rolls, that is the peripheral overlap with respect to say a horizontal plane extending through the rolls, may be varied whilst maintaining the separation between the rolls constant.The arcuate adjustment path is indicated by the dotted line A in Figure 1.

In operation of the applicator, after supplying the desired substance(s) to containers 3 and 4, the web W is drawn by the take up reel 22 from the supply reel 1 8 between rolls 1 and 2 and through dryer 20. The drawing speed, speed and direction of rotation of the rolls 1 and 2, lap of the rolls 1 and 2 and positions of the doctor blades 9 and 10 are adjusted to give the desired application of the desired substance on both sides of the web W.

The resultant treated web may be monitored mechanically, electrically or optically, and a feed back loop provided in order to provide for the continuous control of the desired product. In view of the number of variables effecting the end product, a microprocessor based monitoring system controlling individual roll speeds may be advantageous. In the embodiment of Figure 1, the rolls 1 and 2 are shown driven at the same speed in the opposite direction to the direction of travel of the web W. The speed of the rolls 1 and 2 may be equal to, or less or greater than that of the web W. Alternatively, the rolls 1 and 2 may be driven in the same direction as the web at a speed less or greater than that of the web. With such arrangements, the substance(s) carried out of the containers 3 and 4 by the rolls 1 and 2 is wiped onto the web W by those rolls.The rolls 1 and 2 may also be independently driven at the speeds and in the directions mentioned above thus enabling different speeds to be imparted to these rolls perhaps to cater for different substances being applied thereby to respective opposite surfaces of the web W. In some cases the rolls 1 and 2 may simply be free running and driven by the passage of the web W between them.

Figure 2 shows a modification of the applicator roll arrangement of Figure 1. In this modification, the web W approaches the rolls (here referenced 201 and 202 from below and container 203 and 204) containing substances into which the rolls dip are disposed beneath respective rolls. With such an arrangement both rolls could be gravurea and no doctor blade would be required. In other respects, the applicator would be the same and would operate in the same way as the applicator of Figure 1. The web to which the substances are applied may be any one of the following: woven fabric, knitted fabric, non-woven materials, yarn sheets, paper or any other flexible laminate material, and the substances could be any of the following: PVC, P.U., rubber, natural or synthetic, acrylics, resins, epoxy, phonolic or other, aqueous and solvent based materials including dyestuffs, pigments and printing pastes, any of which may be foamed or non-foamed.

Substances of virtually any viscosity may be used by appropriate adjustment of machine parameters, from free flowing water or solvent based substances to extremely viscous materials.

With extremely viscous materials, it may be convenient to heat the substance and the rollers so as to reduce the viscosity during application, and this would also lead to a simpler drying process.

Claims

1. An applicator for continuously applying a substance to both sides of a length of material comprising first and second rotatable members and means for containing the substance to be applied, the arrangement being such that in operation substance may be transferred from the means for containing to the rotatable members and applied thereby to opposite sides respectively of the length of material as it passes between them.

2. An applicator as claimed in claim 1, in which means are provided for driving at least one of the rotatable members.

3. An applicator as claimed in claim 2, in which the means for driving comprises a drive to one of the rotatable members and a driving connection between the two members or independent variable speed drives to each member.

4. An application as claimed in claim 3, in which the driving connection between the two members enables them to be driven at different speeds.

5. An applicator as claimed in claim 2, in which the means for driving comprises an independent variable speed drive to each of the rotatable members.

6. An applicator as claimed in any preceding claim, in which the means for containing comprises two baths disposed respectively adjacent the two rotatable members so that in operation the members dip into the substance in the baths.

7. An applicator as claimed in any preceding claim, in which in relation to the path of approach of the length of material to the rotatable members the peripheries of the rotatable members overlap so that the direction of travel of the material is altered as it passes between the members.

8. An application as claimed in any preceding claim, in which the position of one of the rotatable members is adjustable relative to the other rotatable member.

9. An applicator as claimed in Claim 8, in which the adjustable rotatable member is mounted in relation to the other rotatable member so that it can follow an arcuate path about the center of the axis of the said other member.

10. An applicator as claimed in any preceding claim in which means are provided for limiting the thickness of substance on at least one of the rotatable members.

1 An applicator as claimed in claim 10, in which the means for limiting comprises a doctor blade or knife.

12. An applicator as claimed in claim 10 or 11, in which the means for limiting is adjustable.

1 3. An applicator for continuously applying a substance to both sides of a length of material substantially as hereinbefore described with reference to Figure 1 or to Figures 1 with the modification of Figure 2 of the accompanying drawings.