US2574083A - Drying apparatus - Google Patents

Description

NOV. 6, 1951 ANDREWS 2,574,083

DRYING APPARATUS Filed Dec. 14, 1950 2 SHEETSSHEET l n faweni'oi": 1362 2202 01 R.fl?adi ews, by C .M

fliiowney Nov. 6, 1951 B. R. ANDREWS DRYING APPARATUS 2 SHEETS-SHEET 2 Filed Dec. 14, 1950 MWWW way I m J Patented Nov. 6, 1951 UNITED STATES T ATENT ()FFICE 4 Claims.

This invention relates to drying apparatus for drying web material of the type in which said web material to be dried is carried through a drying chamber by a pair of traveling tenter chains, each of which has a row of pins on which an edge of the web is impaled, and the invention relates particularly to a drying apparatus of this type in which the drying is accomplished by directing high velocity jets of heated air or other gaseous drying medium against the web as it travels through the drying chamber in the manner shown in my United States Patent #2,071,015, February 16, 1937.

One of the dimculties encountered in the operation of a pin tender drying apparatus is that sections of the web at one edge or the other occasionally become dislodged from the pins while the web is traveling through the drying chamber, and if this occurs such sections of the web are nbt held under proper tension and imperfect drying of the web may result. One object of this invention is to provide means for overcoming the above difficulty and insuring that the web will be securely held on the tenter pins throughout the entire drying operation.

A further object of the invention is to provide a means for holding the web on the tenter pins by displacing the web downwardly along a narrow zone immediately inside each row of tenter pins.

In drying apparatus such as shown in my said Patent #2,071,015, the heated air which is directed against the web for drying it flows off from the web at the edges thereof, and another object of the invention is to provide a construction by which the downward displacement of the web along said zones is produced by the flow of the air off from the edges of the web.

In the drawings wherein I have illustrated a selected embodiment of the invention, Fig. 1 is a cross sectional view through a drying apparatus embodying my invention taken on the line ll, Fig. 2.

Fig. 2 is a fragmentary longitudinal section of a drying apparatus embodying my invention taken on the line 22, Fig. 1.

Fig. 3 is an enlarged fragmentary vertical sec tion through one of the tenter chains and one edge of the web illustrating the manner in which the web is displaced downwardly adjacent the tenter chains and thereby securely held on the tenter pins.

Referring to Fig. 2, which, as stated above, is a longitudinal sectional view through a part of a drying apparatus of the type shown in my Patent #2,071,015, 2 and 3 represent upper and lower air ducts which are supplied with heated air under considerable pressure and which form between them a drying space 4 through which the web 5 to be dried is carried by means of tenter chains as will presently be described, said web moving in the direction of the arrow as in Fig. 2.

The bottom floor 6 of the upper air duct 2 is formed with a plurality of nozzles I through which drying medium, such as heated air under pressure, is delivered against the upper face of the web 5, and the top wall or ceiling 8 of the lower air duct 3 is similarly provided with a plurality of nozzles 9 through which the heated air or other drying medium is delivered under pressure against the under side of the web 5.

Said nozzles 1 and 9 are preferably in a form to provide slots [0 which extend transversely across the web 5, with the result that the jets of air 20 issuing through the nozzles have a sheetlike form. If these sheet-like jets are delivered against the web at substantially right angles thereto and at a relatively high velocit they become, upon contact with the web, converted into whirling cyclonic currents as set forth in said Patent #2,0'71,Q15, which currents finally flow oil? from the web at the edges thereof through the open spaces l l between the air ducts at both sides thereof.

The web 5 of cloth or other material is supported by and carried through the drying space 4 by means of two traveling tenter chains l2, one at each side of the web 5. The tenter chains are of the pin type, and each has a row of pins IS on which an edge of the web is impaled, said chains being supported in their traveling movement by rail assemblies M, as usual in tenter chain devices of this type. Each rail assembly 14 includes longitudinally extending track members or guides I1 and 24 by which the tenter chain is guided in its movement.

The parts thus far described are such as are commonly found in pin tenter chain drying apparatus and form no part of the present invention, which, as stated above, relates to means for maintaining the edges of the web 5 securely impaled on the tenter pins l3.

Located above the web at each edge thereof and relatively close thereto is a baflle strip 15 which extends longitudinally of the web immediately inside of the inner edge of the corresponding tenter chain l2 as best seen in Fig. 3. Each baflie strip I5 is shown as being mounted on and supported by a plurality of bracket arms I6 which, in turn, are mounted on the correthe throat I8 along with air which is flowing I over the surface of the web in contact therewith, as indicated by the arrows IS in Fig. 3. This flow of air against, the baflle strip and downwardly against the web produces an increased pressure on the upper face of the web 5 along a longitudinally extending zone 2| immediately inside the baffle strip l5, and said increased pressure tends to displace the material of the web in said zone downwardly and thereby the edge of the web is more firmly held on the tenter pins.

The present invention also provides means whereby the air which is flowing off from the web beneath the latter at the edges thereof creates a reduced pressure beneath the web along said longitudinally extending zones 2| so that the web in each zone is maintained in its depressed condition partly by the increased pressure on the upper face of the web along said zone and partly by the reduced pressure underneath the web along said zone.

Situated beneath the web 5 at each edge thereof and directly below the upper bafile strip I5, is a lower bafiie strip 22 which has its width dimension extending horizontally. Each lower baffle strip 22 extends longitudinally of the web and is secured to the guide or track member 25 of the rail assembly by means of suitable hangers 23.

Each lower baflle strip 22 is situated relatively near the lower nozzles 9 and has such relation to the web and to the track member 24 that the air current flowing off from the web beneath the latter and which passes through the space 25 between the guide member 24 and the lower baffle strip 22, tends to produce a reduced pressure on the under side of the web along the zone 2|.

My invention, therefore, provides means whereby the web is subjected to unbalanced pressure pressure on the upper face of the web greater than on the lower face thereof, and thereby the web along each of said zones tends to be displaced downwardly with the result that the edge the web jets of air which flow off from the web at each edge thereof, the combination with said tenter chains, each having a row of pins on which a marginal edge of the web to be dried is impaled, of a bafile strip extending longitudinally of the web at each edge thereof, and means supporting each baffie strip above the web immediately inside the corresponding tenter chain, whereby air flow ing off from the edges of the web impinges against and is deflected downwardly by said baffle strips, thereby producing an increased pressure against the top surface of the web along a zone extending longitudinally thereof immediately inside of each bafile strip, which increased pressure tends to displace downwardly the web in each zone and thus more securely hold the edges of the web on the tenter pins.

2. A drying apparatus comprising a drying chamber, a pair of pin tenter chains for carrying the web to be dried through said drying chamber, each tenter chain having a row of pins on which the edge of the web is impaled, means to direct against the under face of the web jets of air which flow off from said face at the edges thereof, and means cooperating with the air thus flowing off from the under face of the web to produce a reduced pressure against the under face of the Web along a marginal zone immediately inside of each row of pins, which reduced pressure is less than that above the web along said zones, such unbalanced pressure tending to displace downwardly the material of the web in each zone and thereby more securely hold the Web on the tenter pins.

3. A pin tenter drying apparatus of the type having a drying chamber, a pair of pin tenter chains for conveying the web to be dried through said drying chamber, and means to direct against both the top and bottom surfaces of saidweb jets of air which flow off from both surfaces at the edges of the web, the combination with said tenter chains, each having a row of pins on which a marginal edge of the web to be dried is impaled, of a baffle strip extending longitudinally of the web at each edge thereof, means supporting each baflie strip above the web immediately inside the corresponding tenter chain, whereby air flowing off from the top surface of the web along a zone 2| at each edge thereof with the at each edge thereof lmpmges agamst Sam baffle strips and is deflected thereby downwardly against the web, thereby producing an increased pressure against the top surface of the web along a zone extending longitudinall thereof immediately inside of each baflie strip, and means ccof the web will be more firmly retained on the tenter pins l3.

It will be understood, of course, that the rail assemblies 14 on opposite sides of the tenter frame are of the type which can be adjusted toward and from each other to accommodate webs of cloth or other material of different widths, and since the upper and lower baffles are mounted on the rail assemblies, the proper positions of said baifles relative to the tenter pins is not disturbed by any adjustment of the rail assemblies.

The drawing indicates a single pass tenter, but it will be understood that the invention is equally applicable to tenters in which the passes are either of the over and under return type or the multiple pass type.

I claim:

1. In a pin tenter drying apparatus of the type having a drying chamber, a pair of pin tenter chains for conveying the web to be dried through said drying chamber, and means to direct against operating with the air flowing ofi from the under face of the web at each edge thereof to produce a reduced pressure against the under side of the web along each of said zones, said increased pressure on the upper face of the web and the reduced pressure on the under face of the web co-acting to hold more securely the edges of the web on the tenter pins.

4. In a pin tenter drying apparatus of the type having a drying chamber, a pair of pin tenter chains for conveying the web to be dried through said chamber, each tenter chain having a row of pins on which a marginal edge of the web to be dried is impaled, a rail assembly for supporting each tenter chain, a series of upper nozzles to direct against the top face of the web jets of air which flow off from the web at each edge thereof, and a series of lower nozzles to direct against the under face of the web other jets of air which flow off from said under face at the edges thereof,'the combination with said tenter chains, rail 5 1 assemblies and nozzles, of an upper baffie strip extending longitudinally of the web at each edge thereof, means supporting each upper baffle strip above the web immediately inside the corresponding tenter chain, whereby air flowing 01f from the edges of the web impinges against said bafile strips and is deflected thereby downwardly against the web thus producing an increased pressure against the top surface of the web along a zone extending longitudinally thereof immediately inside of each baille strip, a lower baflle strip also extending longitudinally of the web at each edge thereof, and means supporting each lower bafile strip below the web relatively near the lower nozzles and spaced from the corre- 1 sponding rail assembly, and with its width dimension extending parallel to the web, whereby the flow of air from the lower nozzles over each 6 lower bafile strip and between the latter and the corresponding rail assembly produces a reduced pressure on the under face of the web along each of said longitudinal zones, which reduced pressure cooperates with the increased pressure on the upper face of the web to hold more securely the edges of the web on the tenter chains.

BERNARD R. ANDREWS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,717,004 Buck June 11, 1929 2,083,141 Buck June 8, 1937 2,083,142 Buck June 8, 1937

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