US3577652A - Apparatus for the drying of sheet material - Google Patents

Abstract

An apparatus for applying heated air to the surface of a sheet material has a dryer surface at an outer wall of a boxlike structure, the dryer surface being defined by alternate openings and apertured surface regions in the said outer wall, the apertured surface regions being connected together inwardly of the boxlike structure and being isolated from the openings, and a substantially closed air circulation system is developed by the apparatus when in use, air passing outwardly through the apertured surface regions and inwardly through the openings, or vice versa, during the surface treatment of a sheet material arranged in closely spaced adjacent disposition relative to the dryer surface. For simultaneous treatment of both surfaces of a sheet material two apparatuses as aforesaid will be used, such apparatuses being arranged in opposed closely spaced disposition with the material passing therebetween, and the air circulation systems of the individual apparatuses will be isolated one from the other to enable independent treatment conditions to exist at the opposite sides of the material.

Description

United States Patent [72] Inventors Raymond Victor Evans Blackburn, England; John Edward Hibbitt, Darwen, England [21] Appl. No. 807,855 [22] Filed Mar. 17, 1969 [45] Patented May 4, 1971 [73] Assignee Singer-Cobble Limited Blackburn, Lancashire, England [32] Priority Mar. 18, 1968 [3 3] Great Britain [3 1 12970/68 [54] APPARATUS FOR THE DRYING 0F SHEET MATERIAL 14 Claims, 7 Drawing Figs.

[52] U.S. Cl 34/155 [51] Int. Cl F26b 13/02 [50] Field of Search 34/155, 162, 164

[56] References Cited UNITED STATES PATENTS 1,642,928 9/1927 Kocha 34/162 3,151,950 10/1964 Newman et al. 34/155X 3,371,427 3/1968 Thygeson ABSTRACT: An apparatus for applying heated air to the surface of a sheet material has a dryer surface at an outer wall of a boxlike structure, the dryer surface being defined by alternate openings'and apertured surface regions in the said outer wall, the apertured surface regions being connected together inwardly of the boxlike structure and being isolated from the openings, and a substantially closed air circulation system is developed by the apparatus when in use, air passing outwardly through the apertured surface regions and inwardly through the openings, or vice versa, during the surface treatment of a sheet material arranged in closely spaced adjacent disposition relative to the dryer surface.

For simultaneous treatment of both surfaces of a sheet material two apparatuses as aforesaid will be used, such apparatuses being arranged in opposed closely spaced disposition with the material passing therebetween, and the air circulation systems of the individual apparatuses will be isolated one from the other to enable independent treatment conditions to exist at the opposite sides of the material.

PATENTEUHAY 4m 3.577552 SHEET H []F 4 INVENTORS 54/0100! I/Ic ran Ewan 1 APPARATUS FOR THE DRYING or SHEET MATERIAL Theinvention concernsiapparatus for't he heating, drying,

' and/or curing, or other treatment of sheet materials or of coatings applied thereto, hereafter, for convenience, referred to simply as apparatus for drying sheet material, and has par- I tufted carpet problemsare met with in view of the comparatively large quantity of liquids which, of necessity, must be removed in a short period of time if the overall drying time is to be held within practical limits.

It is known to dry a weblike material by applying heated air connecting said openings, the apertured surface regions and.

openings being isolated one from the other inwardly of the said surface, and air circulation means adapted to feed air to the apertured regions through the first said ducting and to receive air from theopenings through the second said ducting, the whole being adapted to define, together with a web located adjacent the dryer surface, an independent closed air recirculation system for the treatment of a web at a surface thereof.

A heat exchange means will usually be provided in the path of the air, such means being adapted to apply heat to or to 7 remove heat from such air during the circulation thereof.

to a surface-of the material at one location and to apply a reduced air pressure at an immediately adjacent location so as to give rise to an air circulation at the surface fordrying purposes. Apparatus for practicing this method comprises a closed body part through which the material under treatment passes, areas of perforations and apertures arranged alternately in the intended direction of movement of the material, a fan at each lateral edge of the said material and arranged to supply air to the areas of perforations and to draw air inwardly through the apertures, and a heater rneans through'which the air passes in its path of movement from the apertures to the fan. In the aforesaid apparatus the arrangement is such that both surfaces of the material are simultaneously subjected to a drying treatment, the rotational axes of the fans lying in the plane of the web and each such fan supplying air both to the top and to the bottom surface of the weblike material.

In the apparatus aforesaid, both top and bottom surfaces of the material are subjected to a like treatment, the apparatus being of such character as to preclude the possibility of treating a single surface only and of isolating the other surface during such treatment.

Furthermore,' the provision of a fan adjacent each lateral edge of the material under treatment gives rise to an unfavorable air circulation pattern in that, generally, each fan creates an airflow pattern at one side only of the apparatus, each such airflow pattern reaching above and belowthe material at one side thereof. It is possible that in practice the'weblike material will be subjected to a nonuniform treatment throughout its width at each surface. The utilization of a separate heater means at each face of the material and for each fan will increase the possibility of a nonuniform treatment since tem In a preferred embodiment the second said ducting is defined in part by the dryercasing, the alternately disposed apertured regions and apertures defining a wall of such casing, and the first ducting is disposed inwardly of the casing.

Preferably the apertured surface regions and openings are arranged in successive side-by-side dispositions in the trans verse direction of the dryer, the axes of the apertured regions and openings being inclined to such transverse direction so as to give an overlap of successive apertured regionis when viewed in the direction of movement of the fabric being dried. In practice it will be usual to provide a plurality of dryers as aforesaid, each such dryer being paired with another like dryer and being arranged in closely spaced opposed disposition relative thereto to allow passage of the material therebetween. Preferably, the separation of the dryer surfaces The primary object of the present invention is to provide an apparatus for drying sheet material which avoids the aforementioned difficulties and allows of the uniform treatment of the whole of one surface of a weblike material to the exclusion of the other surface thereof.

According to the present invention apparatus for drying sheet material comprises a closed boxlike structure having an outer surface thereof, which surface constitutes the dryer surface, defined by openings and apertured regions, and an air circulation means withinthe structure and adapted to apply pressure air to the apertured regions for discharge from the box through such regions and to apply a reduced pressure in the region of the openings to draw air inwardly through such openings, the openings and apertured regions being so adapted and arranged as to give a substantially even distribution of airflow outwardly of the surface.

I Preferably, the apparatus includes a plurality of apertured surface regions and openings which collectively define a dryer surface, such regions and openings being arranged alternately and in immediately adjacent disposition so that all sections of a surface of a material under treatment and moving relative to the dryer surface in the longitudinal or transverse direction of the apparatus are subjected to alike treatment, a first ducting connecting said apertured surface regions, a second ducting of the opposed dryers does not exceed 4 inches.

The invention also includes the combination of an apparatus as aforesaid with one or more like such apparatuses.

The invention will now be described further by way of example only with reference to the accompanying drawings illustrating one embodiment thereof and in which:

FIG. I is a perspective view, from below, of a dryer module constructed in accordance with the present invention;

FIG. 2 is a transverse section through the module of FIG. 1;

FIG. 3 is a section taken on line III-III of FIG. 1;

FIG. 4 is a vertical section, drawn to an enlarged scale, through an explosion panel as fitted to the module and taken on line IV-IV of FIG. 5;

FIG. 5 is a perspective view from one end of a dryer embodying four of the modules as shown in FIG. 1;

FIG. 6 is a diagrammatic perspective view of a baffle arrangement as embodied in the dryer shown in FIG. 5 for the purpose of reducing heat losses between the dryer and the atmosphere and between upper and lower sections of the dryer; and

FIG. 7 is a diagrammatic representation of the air exchange which takes place within the dryer during usage thereof, the dryer being viewed from above.

Referring now to the drawings, and-particularly to FIGS. 1 to 3 thereof, a dryer module comprises a heat'insulating casing ll, a plurality of apertured surface regions 12 and openings 13 arranged alternately at one face of the casing and defining a wall thereof, an air circulation means 14 extending within the casing, such means receiving air from outside the casing through the openings'13 and delivering air to the apertured surface regions 12 for discharge therethrough, a first ducting l5 connecting the apertured regions and putting same in communication with the air circulation means 14 at the output side thereof, and a second ducting 16connecting the openings and putting same in communication with the inlet side of the air circulation means.

The casing 11 is generally rectangular, having spaced sidewalls Ila and end walls llb, and a top wall 11c. The un- 3 The first" ducting l5, see FIG. 3, basically comprises a passageway defined by spaced sidewalls 15a and a top cover 15b, the said sidewalls being outwardly cranked at the lower regions thereof, as at 15a, to extend to the lower edge of the corresponding wall Ila of the casing and the top cover having a first part which is disposed substantially horizontally and a second part which extends downwardly away from the said first part. The ducting is completed by forward and rearward end walls 15c respectively, such walls each having upper and lower regions 15c joined by an horizontal plate 15:" and each extending downwardly to the underside of the casing.

The ducting is also provided with a transverse body 15d which acts in the nature of a partition to define on either side thereof and at the respective ends of the ducting forward and rearward outlet. ports 15e, 15f to the said ducting and an inclined baffle 15g is positioned within the ducting to divide the airflow from the fan which constitutes the air circulation means 14 between such forward and rearward ports, the said baffle 15g being disposed forwardly of the transverse body in the direction of airflow.

The apertured surface regions 12 aforesaid are constituted by apertured plates which extend across the outer end of the ducting l5 and in the plane of the underside of the casing 11, the said plates being arranged in spaced parallel disposition and each being inclined to a line extending between and at right angles to the sidewalls 11a of such casing. The dimensions and the angle of inclination of the plates is such that successive such plates overlap in the direction of motion of a web thereby. By providing the diagonal arrangement of the plates it is possible to pass a material under processing in either of two directions which are mutually inclined at 90 one such direction corresponding to the widthwise direction of the module and the other the lengthwise direction thereof.

An iris-type baffle or some alternative damper means, not shown, may be provided to allow of the control of air velocity from the fan, if desired.

The second ducting 16 is defined in part by the upper regions of the casing outwardly of the first ducting and in part by transverse passageways 16a extending along the lower edge of the casing and inwardly thereof, the said passageways being in communication with the said upper region and also with the openings 13 in the underside of the casing. The transverse passageways 16a are each constituted by the respective sidewalls Ila of the casing, the sidewall 15a of the first ducting arranged in spaced disposition relative thereto, the downwardly and outwardly inclined extremity 15a to such wall, and an horizontal plate 16!; extending between the said sidewalls and at a position approximately at or slightly below the lower edge of the explosion panels 17. The passageways are joined together by conduits 16c extending therebetween and disposed at the lower edges and inwardly of the casing,

such conduits having sidewalls defined by the end walls of the casing and the end walls of the first ducting and lower and upperwalls constituted by a wall of the casing and an additional top plate 16c respectively. An opening 16d is provided in the top of one of the conduits whereby such conduit is put in communication with the upper region of the casing.

The second ducting is completed by means Me which isolate the openings 13 from the apertured regions, such means comprising two spaced side plates Me for each openings, which plates are of inverted W-shape and extend inwardly of the casing from the adjacent edges of two successive apertured plates, and two mutually inclined cover plates l6e" arranged within the angle of the side plates, the outer edges of the side plates engaging the underside of the cranked lower regions 15a of the sidewalls of the first ducting. Each opening 13 is put in communication with the transverse passageways 16a by through apertures 18 in the cranked lower regions aforesaid. Preferably, the successive openings 13 are of reducing size towards the heater end of the module thus to facilitate the maintaining of a unifonn treatment at all regions widthwise of the material under processing.

An explosion panell7 is shown in cross section in FIG. 4 and comprises a body 17a of heat insulating material supported between two spaced, frangible plates 17b, the. said body and plates being mounted relative to an opening Ila in the respective sidewall 11 by a rectangular clamping strip 17c secured to the outer wall of the casing. The inner face of the panel presents a rigid mesh structure 17d thereby to impart a requisite amount of rigidity to the panel as a whole. The innermost plate bears against the outwardly facing surface of a lip formed in the sidewall, whilst the outermost plate bears against the outer surface of the wall about the periphery of the opening, the clamping strip 170 overlying the edge of the plate and being secured to the casing by screws l7e arranged outwardly of the periphery of the plate. Preferably, the frangible strips are fabricated from Superite" whilst the heat insulating material comprises soft glass fiber wadding sold under Trade Name Cosywrap.

The air circulation path for the dryer is indicated by the arrows'in FIG. 2 of the drawings and it will be seen that the fan 14 draws air past the burner 17 to the lower pressure side of the fan and such heated air is fed to the first ducting 15. The air then passes along the said ducting through the forward and rearward outlet ports to the apertured plates, the said air issuing from the apertures in such plates as a multiplicity of pressure jets which impinge on a web or like material moving adjacent to the said plates. The openings are connected with the low pressure side of the fan and hencea reduced air pressure is applied in the region of the openings, thus being drawn from adjacent the surface of the web and passing through the passageways to the conduit and thence, via a filter member, to the region of the burner and finally back to the fan for continu'ed circulation.

Any moisturepicked up from the web by the heated air will be drawn into the casing and by arranging that the air within the casing is continually replenished by outside air at a controlled rate and that moisture laden air is exhausted to atmosphere, so the drying of the web can be effected.

In practice it will be usual to utilize a plurality of the dryer modules of the character of that shown in FIGS. 1 to 3, and a typical installation is shown in FIG. 5 where four modules are employed.

Thus, referring now to FIG. 5, four dryer modules of the character of that described with reference to FIGS. 1 to 3 are provided, the modules being arranged in closely adjacent opposed spaced disposition. Each module has its own burner and air circulation means and each of the modules is separately controllable.

The relative dispositions of the individual modules 20 which collectively define the dryer shown in FIG. 5 are such as to provide a narrow slot 21 through which a material 22 under processing, say a tufted carpet or like material, passes, the material being supported on and progressed by a stenter 23 which extends through the unit from front to rear. Conveniently the stenter 23 will be adjustable as regards its width thus to allow of the processing of materials of different widths. A baffle arrangement 24 will be provided adjacent the laterally movable stenter chain, which movement is effected by any convenient screw or worm drive means 25 in a manner known per se, thus to prevent heat exchange between upper and lower dryer sections, to avoid heat losses from the dryer, and to preclude uncontrolled ingress of outside air.

The baffle arrangement 24 is shown diagrammatically in FIG. 6 and will be seen to comprise a first vertical baffle 24a extending between the laterally movable stenter chain and the end of the slot 21, such baffle serving to close the slot 21 in such region, a second vertical baffle 24b extending along the line of the adjustable stenter chain and disposed within the dryer and an horizontal baffle 24c likewise within the dryer and separating upper and lower dryer sections in the region outwardly of the adjustable stenter.

The first vertical baffle 24a is a ribbon baffle, the strip a casing in which the said strip is coiled.

The horizontal baffle 24c is best seen in FIG. 6 and comprises a plurality of flat elongate elements 24d pivotally secured together as by rings 24c and suspended from tracks 24f by runners 24g. As the adjustable stenter moves back and forth so the mutual inclinations of the elements are varied to increase or to reduce the effective length of the baffle.

Various guide rollers 26, and delivery and takeup rollers 27, 28 are provided, such rollers being driven or not as required.

Access hatches or doors 29 are provided, in the casing of the dryer, as appropriate, and the casing as a whole is insulated against heat losses. The necessary pipework (not shown) for the combustible fuel will of course be provided, as will appropriate exhaust ducting.

The air circulation within the dryer illustrated in FIG. 5 is shown diagrammatically in FIG. 7. Referring now to FIG. 7 of the drawing, the material 71 under processing moves in counterdirection to the movement of the air 72, the air entering initially through an adjustable inlet louvre 73, being circulated within module A, and being transferred, in time, to module B via opening 74 and eventually extracted for discharge to atmosphere through conduit 75. With this arrangement the driest regions of the carpet are subjected to treatment from newly introduced air, or more properly the air having a proportion of newly introduced air, whilst the more moist but equally warm air is applied to the wettest regions of the carpet.

The upper and lower regions of the dryer are isolated one from the other by the material under processing and the horizontal baffle, and not only do such regions have an independent air circulation but such air circulations may well have significantly different temperatures. For example, in one example the temperature of the upper air circulation may be of the order of 450 F. whilst that of the lower circulation may be approximately 200 F.

In another arrangement, not shown, a dryer module is used in combination with a fixed support surface, the module being disposed in spaced apart relationship with the said surface to define a web-receiving space therebetween. The surface will have a heat resistant facing thereto or will be defined by such a material.

We have found that by means of the dryer hereinbefore described we are able to remove the moisture from a latex backed floor cover at a rate which bears very favorable comparison with that achieved by conventional dryers. Furthermore, the utilization of a multitude of jets of pressure air arranged in closely adjacent disposition will assist in the supporting of the material during its passage through the dryer and will in consequence, enable the material to be held at its full width with no or only minimal sag and will thus facilitate the uniform treatment of the material. In the event of fan failure, the stenter will maintain the material at its full width without sag.

Whilst in the arrangements hereinbefore described and illustrated the heating of the air has been by means of a gas or like burner, in no way is the invention so restricted in that alternative means may be found to be preferable in some circumstances. Thus, for example, a heater coil may be provided in the path of the airflow instead of utilizing a gas or other burner, the coils being located, for instance, in the positions C as indicated in FIG. 2 of the drawings. It should be borne in mind that in some circumstances the requirement may be that heat is withdrawn rather than applied in which case the coils would form a part of a refrigeration or like circuit. In still other circumstances no heat exchange requirement will exist for the circulating air, save for that between such air and the material under treatment, and thus there will be neither heater nor cooler means within the dryer.

Furthermore, whilst the primary application of the dryer is thought to be in the context of drying the synthetic latex backing of tufted carpet or like materials, in no sense is theapplication limited to this specific field or to this particular purpose, since the dryer may well be capable of utilization in connection with any web or sheet material for the drying thereof or for any other treatment where controlled air circulation is necessary.

We claim:

1. Apparatus for drying sheet material comprising a cabinet having oppositely disposed end walls and sidewalls, air supply duct means within said cabinet for supplying a source of high pressure drying air, a dryer surface including a plurality of spaced apertured high pressure duct means operatively connected with said air supply duct means and having their apertures disposed for directing drying air toward the surface of a moving web, said apertured duct means being disposed at an inclined angle to a line "extending between and at right angles to said sidewalls of said cabinet such that successive areas of said apertured duct means overlap said web relative to the direction of travel of said web, return air openings between said apertured duct means with said openings being disposed toward the outer portions of the spaces between said apertured duct means with the remaining portions of said spaces being closed such that the relationship of said spaced apertured duct means, said return openings and a web located adjacent to the dryer surface form an independent closed air circulation system for drying the web.

2. Apparatus as claimed in claim 1 further including an adjustable baffle lying adjacent and outwardly of the dryer surface, the said baffle being movable to close a part of the dryer surface as required.

3. Apparatus as claimed in claim 1 wherein said air supply duct means is defined, in part, by walls of said cabinet, and the spaced apertured duct means defining a portion of a wall of said cabinet.

4. Apparatus as claimed in claim 3 further comprising a return air duct means operably connected with said return air openings, and said return air duct means and said air supply duct means being disposed wholly within said cabinet.

5. Apparatus as claimed in claim 1, wherein said air supply duct means includes two outlet ports communicating with said apertured duct means, an inclined baffle means in air supply duct means and positioned adjacent the first of said outlet ports relative to thedirection of airflow, said baffle means being adapted to deflect air through said first of said outlet ports, and said air supply duct means being of reduced transverse cross section beyond said baffle means.

6. Apparatus as claimed in claim 1 wherein an additional apparatus is disposed above and in spaced disposition to said first-mentioned apparatus to define a web receiving opening therebetween, the said two apparatuses being joined along corresponding lateral edges thereof.

7. The combination as claimed in claim 6 including an adjustable baffle arrangement adapted to close the web receiving opening laterally outwardly of a web passing therebetween.

8. Apparatus as recited in claim 7 including a webprogressing means extending through said web receiving opening and said web-progressing means being adjustable laterally so as to adapt for webs of differing widths.

9. The combination as claimed in claim 7 including a further adjustable baffle arrangement extending between the dryer apparatuses and lying in the direction of movement of the web, the said further arrangement being adapted to separate the air circulation in the apparatuses and to limit heat losses at the edges of the web.

10. The combination as claimed in claim 9 wherein the further adjustable baffle arrangement includes a first part extending between the individual apparatuses and a second part lying between such apparatuses and in a plane substantially parallel to the dryer surfaces, the second such part comprising a plurality of elongate elements pivotally connected in edgeto-edge configuration.

11. Apparatus as claimed in claim 1 including heat exchange means in the path of the air, such means being adapted to apply heat to or to remove heat from such air during the circulation thereof.

12. Apparatus for drying sheet material as claimed in claim 1 in combination with at least one additional such apparatus arranged in side-by-side disposition relative thereto.

13. The combination as claimed in claim 12 wherein each successive apparatus is reversed relative to the previous apparatus.

14. The combination as claimed in claim 12 wherein air exchange means are provided between each succeeding apparatus and the previous apparatus, such means being adapted to transfer air between the apparatuses.

Claims (14)

1. Apparatus for drying sheet material comprising a cabinet having oppositely disposed end walls and sidewalls, air supply duct means within said cabinet for supplying a source of high pressure drying air, a dryer surface including a plurality of spaced apertured high pressure duct means operatively connected with said air supply duct means and having their apertures disposed for directing drying air toward the surface of a moving web, said apertured duct means being disposed at an inclined angle to a line extending between and at right angles to said sidewalls of said cabinet such that successive areas of said apertured duct means overlap said web relative to the direction of travel Of said web, return air openings between said apertured duct means with said openings being disposed toward the outer portions of the spaces between said apertured duct means with the remaining portions of said spaces being closed such that the relationship of said spaced apertured duct means, said return openings and a web located adjacent to the dryer surface form an independent closed air circulation system for drying the web.

2. Apparatus as claimed in claim 1 further including an adjustable baffle lying adjacent and outwardly of the dryer surface, the said baffle being movable to close a part of the dryer surface as required.

3. Apparatus as claimed in claim 1 wherein said air supply duct means is defined, in part, by walls of said cabinet, and the spaced apertured duct means defining a portion of a wall of said cabinet.

4. Apparatus as claimed in claim 3 further comprising a return air duct means operably connected with said return air openings, and said return air duct means and said air supply duct means being disposed wholly within said cabinet.

5. Apparatus as claimed in claim 1, wherein said air supply duct means includes two outlet ports communicating with said apertured duct means, an inclined baffle means in air supply duct means and positioned adjacent the first of said outlet ports relative to the direction of airflow, said baffle means being adapted to deflect air through said first of said outlet ports, and said air supply duct means being of reduced transverse cross section beyond said baffle means.

6. Apparatus as claimed in claim 1 wherein an additional apparatus is disposed above and in spaced disposition to said first-mentioned apparatus to define a web receiving opening therebetween, the said two apparatuses being joined along corresponding lateral edges thereof.

7. The combination as claimed in claim 6 including an adjustable baffle arrangement adapted to close the web receiving opening laterally outwardly of a web passing therebetween.

8. Apparatus as recited in claim 7 including a web-progressing means extending through said web receiving opening and said web-progressing means being adjustable laterally so as to adapt for webs of differing widths.

9. The combination as claimed in claim 7 including a further adjustable baffle arrangement extending between the dryer apparatuses and lying in the direction of movement of the web, the said further arrangement being adapted to separate the air circulation in the apparatuses and to limit heat losses at the edges of the web.

10. The combination as claimed in claim 9 wherein the further adjustable baffle arrangement includes a first part extending between the individual apparatuses and a second part lying between such apparatuses and in a plane substantially parallel to the dryer surfaces, the second such part comprising a plurality of elongate elements pivotally connected in edge-to-edge configuration.

11. Apparatus as claimed in claim 1 including heat exchange means in the path of the air, such means being adapted to apply heat to or to remove heat from such air during the circulation thereof.

12. Apparatus for drying sheet material as claimed in claim 1 in combination with at least one additional such apparatus arranged in side-by-side disposition relative thereto.

13. The combination as claimed in claim 12 wherein each successive apparatus is reversed relative to the previous apparatus.

14. The combination as claimed in claim 12 wherein air exchange means are provided between each succeeding apparatus and the previous apparatus, such means being adapted to transfer air between the apparatuses.

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