US3782003A

US3782003A - Device for shifting products to be dried on a perforated drying drum

Info

Publication number: US3782003A
Application number: US00172009A
Authority: US
Inventors: F Garzotto
Original assignee: Rimar SpA
Current assignee: Rimar SpA
Priority date: 1970-08-22
Filing date: 1971-08-16
Publication date: 1974-01-01
Anticipated expiration: 1991-01-01
Also published as: NO131139C; ES198112Y; ES198112U; BE771521A; FR2104549A5; NO131139B; GB1368099A; SE385922B; NL7111356A; DE2140808A1

Abstract

A device for shifting products to be dried on a perforated drying drum in order to increase the drying efficiency and to prevent the formation of a pattern of the drum holes on the same products, comprises a cylinder, having its longitudinal axis parallel to the axis of the drying drum, at a given distance which is adjustable. Said cylinder can be actuated by a side drive independently of the actuating system of said drum. When the diameter of said cylinder has been chosen, the distance from the drum surface can be varied in order to avoid the increase in the path of the product due the device becoming equal to the center distance between the drum holes or an integral multiple thereof. A plurality of these devices can be advantageously mounted on a drying drum.

Description

United States Patent Garzotto [75] Inventor: Felice Garzotto, Valdagno, Italy [73] Assignee: Rimar S.p.A., Trissino, Vicenza,

Italy [22] Filed: Aug. 16, 1971 21 Appl. No.: 172,009

[30] Foreign Application Priority Data Aug. 22, 1970 Italy 28885 A/70 [52] US. Cl. 34/110 [51] Int. Cl. F26g 13/12 [58] Field of Search 34/23, 24, 41, 110,

[56] References Cited UNITED STATES PATENTS 3,591,151 7/1971 Kerner 34/110 1,564,775 12/1925 Green et a1. 34/110 X 2,440,839 5/1948 Apgar et a1. 34/110 2,788,587 4/1957 Dsenis 34/110 2,532,910 12/1950 Hayward ..34/115 Primary Examiner-Charles J. Myhre Assistant ExaminerTheophil W. Streule, Jr. Att0rneyAlvin Browdy and Sheridan Neimark [5 7] ABSTRACT A device for shifting products to be dried on a perforated drying drum in order to increase the drying efficiency and to prevent the formation of a pattern of the drum holes on the same products, comprises a cylinder, having its longitudinal axis parallel to the axis of the drying drum, at a given distance which is adjustable. Said cylinder can be actuated by a side drive independently of the actuating system of said drum. When the diameter of said cylinder has been chosen, the distance from the drum surface can be varied in order to avoid the increase in the path of the product due the device becoming equal to the center distance between the drum holes or an integral multiple thereof. A plurality of these devices can be advantageously mounted on a drying drum.

5 Claims, 4 Drawing Figures PATENIEDJAH 1 w 3,782,003

SHEET 3 0F 3 ARM WITH ARM WITH SQR DRIVING BELT DRIVING BELT CYLINDER SIDES OF THE DRYING,

CHAMBER Fig.5

DEVICE FOR SHIF TING PRODUCTS TO BE DRIED ON A PERFORATED DRYING DRUM BACKGROUND OF THE INVENTION The present invention relates to a device adapted to shift a product to be dried, such as fabric pieces, on a perforated drying drum in order to avoid the impressions of the drum holes being left on the product, and to increase the drying efficiency.

It is'known that a fabric of whatsoever type (woven or'non-woven) can be dried by means ofa device which comprises a drum having a suitable diameter, the outer surface thereof being formed by perforated plate or a net provided with a plurality of holes having anypredetermined diameter and distance between them. The liquid (water or solvents which may contain chemicals which are to be left on the fabric to give particular features thereto),-which initiallyimpregnates the fabric, is extracted by letting through said holes a flow of air at a suitable'temperature, drawn from the outside into the inside of the drum by a special fan.

It is also known that, this air, passing exclusively through the drum holes and therefore through the fabric approximately at those areas which correspond to the regions placed upon the holes, removes from the fabric the liquid (water, solvent etc.) impregnating it. The drying thus begins by evaporation of the liquid in that areade'finedby eachindividual hole and continues then in 'the remaining areas with a miscellaneous process which comprises a direct drying ---due to the'heat of the chamber'contain'ing the perforated drum and, what ismore important, a capillary attraction of the liqu'i'd from the areas still wet or, in any-case, more wet, which are comprised between the holes, towards the less wet or even dry areas corresponding to the holes. This causes such irregularities that the fabric may sometimes be commercially unacceptable, both when said drum -.is employed merely to extract the liquids from 'the'fabric, leaving the latter dry and'free from any chemicals, and when such extraction is accomplished inorder to leave on the fabric some chemicals which have previously and intentionally been introduced into the liquid so as to give the fabric some useful features. lnany case, particularly when, as stated hereinabove, certain chemicals are to be left on the fabric, there occur, during the'drying, migrations ofliquids towards the areas associated with the drum holes and simultaneously therewith migrations of the chemicals contained in the liquids, thus causing irregularities in the distribution of these chemicals with a consequent unevenness in the final characteristics of the fabric which sometimes carries thereon a clearly visibile pattern of the drum holes.

SUMMARY OF THE INVENTION It has now been conceived as an object of the present invention a device obviating the above-mentioned drawbacks and which allows at the same time an increase in the drying efficiency and therefore in the output per hour of the fabric dried on the perforated drum.

It has in fact been observed that during the drying the fabric moves with the same peripheral speed as the drum, without slipping with respect to the latter, so that during the whole period of contact the areas of the fabric associated with the perforated areas of the drum are always the same. On the contrary, if, between the drum surface and the fabric, at one or more locations on the d rum along generating lines of the peripheral cylindrical surface of the latter, there are inserted devices which allow the fabric to be disengaged from the drum and then immediately re-engaged on it, the fabric surface which was before associated with the holes will be shifted from its previous position. This may occur one or more times during the period of contact betweenthe fabric and the drum in such a way that so high difference of drying in the same fabric as to allow the abovementioned migrations of chemicals can never occur.

This provides the substantial advantage that no migration of the chemicals contained, or of the residues still dissolved in the liquid which impregnated the fabric occurs, so that these chemicals or residues are equally distributed in the fabric as they were before be ginning the drying on the drum, thus avoiding differences on the fabric or even the reproduction of the hole pattern as mentioned above.

The device according to the present invention provides the further advantage that the areas of the fabric overlying the areas between the drum holeswhere there would be a slower drying with respect to the areas overlying the holesmove little by little so that they first partially and then completely overlie the holes, thus increasing the drying speed and therefore the machine output per unit of time.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects, advantages and features of the device according to the present invention willbe apparent to those skilled in the art upon considering the following detailed description of a preferred embodiment given by way of example, in connection with the accompanying drawings, in which:

FIG. 1 shows a perspective view of a conventional perforated drying drum;

FIG. 2 shows a cross-section of said drum on which DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and in particular to FIGS. 1 and 2, there may be seen that during the rotation of the drum 1 actually no relative movement occurs between the side surface of the latter and the fabric 2 to be dried thereon. As a result those areas of the fabric 2 overlying the holes 3 will perfectly coincide with these during the whole period of contact the same occurring also for those areas of the fabric overlying the non-perforated regions 4 of the drum 1.

Considering now FIG. 3, there are shown two devices 5 according to the present invention, mounted on the drum so that they can vary the path of fabric 2 by causing it to slip. The number of devices which can be mounted on the drum ranges from 1 to n, where n is a maximum number such that the minimum distance between two devices in succession may still allow the fabric to contact again the drum under the effect of suction and other forces which tend to bring it again in such contact position. These devices may be embodied in different ways, the easiest embodiment being a cylinder having its axis parallel to the axis of the perforated drum, at a certain distance from the latter and with a diameter the lower limit of which is given by the possibility of maintaining mechanically said parallelism. The fabric is caused to pass on the cylinder or cylinders 5, slipping from the drum 1, whenever one of these cylin ders is met, and contacting again the drum when the fabric descends from such cylinder. The said cylinders can be actuated by means of a side drive and can be mounted on the machine in such a way that the distance D, from the perforated drum may be adjusted according to the nature of different fabrics, their flexibility, weight and possible tendency to stretch or generally vary their dimensions.

In the limit case, the cylinder may comprise a simple rod or a wire held in a suitable position adjustable with respect to the drum, which also gives excellent results.

Referring now to the FIGS. 3 and 4 there is shown with l the path that the fabric 2 would follow along the periphery of the drum 1, were the device 5 not present. The real path followed by the fabric 2 on the cylinder 5 is indicated with 1,. Therefore the expression l,l is equal to the increase in the path the fabric must follow and is a function of the diameter d of the cylinder 5 and of the adjustable distance D, of the latter from the drum surface. It should be avoided that the value 1 be equal to the center distance i between the holes (see FIG. 4) or to an integral multiple thereof, as in this case that area of the fabric associated with a hole 3, after passing the first device 5, would be in the position 4 (see also FlG. 1) and it would again coincide with another hole after passing a second device 5 in case that I,I=ni, where n is an odd integer. The worst case would occur, should it be an even number, because then after each device 5 the areas associated with a hole 3 would again overlie each time another hole 3 and so on. To get a gradual shifting of the fabric at each device 5, it must be:

where s is a shifting smaller than the hole diameter and the centre distance between the holes, and possibly different from a submultiple of these quantities.

In FIG. 4 there is shown an example where s is A; of the hole diameter, or of the centre distance i. In this case the material overlying the area 4 between the holes after three shiftings will coincide with hole 3 and will return in its initial position after six shiftings, which can be avoided for instance by providing along the perforated drum a smaller number of devices 5, for instance five. In this way the above formula can be used to achieve the best results, where the term 1,-! may be suitably varied by adjusting 0,.

Possible additions and/or modifications to the embodiment of the device according to the present invention as hereinbefore described and illustrated will become apparent to those skilled in the art, without departing from the scope of the appended claims. In particular its employment on perforated drying drums is to be considered exclusively as a particular embodiment, and therefore it is apparent that the device according to the present invention may be advantageously used in an analogous way whenever a relative movement between two moving surfaces in contact with each other is desirable.

What I claim is:

1. In a device for drying continuous lengths of products comprising a rotating perforated drum having a portion thereof over which the product passes and means to cause a flow of air therethrough, the improvement comprising:

cylinder means for increasing the length of the path of travel of the product about said drum with respect to the length of said portion of said drum over which the product passes in an amount different from an integral multiple of the distance between the centers of adjacent holes in said perforated drum, to thereby cause the product to be shifted with respect to the surface of said drum, said cylinder means comprising at least one cylinder adjacent to and externally of said drum having a width substantially coextensive with the width of said drum, the axis of said cylinder being mounted in parallel with the axis of said drum, wherein said cylinder lies between the product and the drum when in use.

2. A device according to claim 1, wherein adjusting means are provided for adjusting the radial distance of the surface of said cylinder from the surface of said drum.

3. A device according to claim 1, wherein said cylinder is actuated by a side drive independently of the actuating system of said drum.

4. A device according to claim 2, wherein as least one of said cylinders is a rod.

5. A device according to claim 2, wherein at least one of said cylinders is a metal wire.

Claims

1. In a device for drying continuous lengths of products comprising a rotating perforated drum having a portion thereof over which the product passes and means to cause a flow of air therethrough, the improvement comprising: cylinder means for increasing the length of the path of travel of the produCt about said drum with respect to the length of said portion of said drum over which the product passes in an amount different from an integral multiple of the distance between the centers of adjacent holes in said perforated drum, to thereby cause the product to be shifted with respect to the surface of said drum, said cylinder means comprising at least one cylinder adjacent to and externally of said drum having a width substantially coextensive with the width of said drum, the axis of said cylinder being mounted in parallel with the axis of said drum, wherein said cylinder lies between the product and the drum when in use.

4. A device according to claim 2, wherein at least one of said cylinders is a rod.