US1487362A - Drying apparatus - Google Patents

Description

March 18 y192111.

' o.. D. RICE DRYINGAPPARATUS Filed March 15.

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o. D. RICE DRYING APPARATUS Filed March 15 '1922 2 sheets-sheet 2 Z Fig. y

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Patented Mar. 18,y 1924.

UNITED STATES PATENT OFFICE.

OTIS D. RICE, OF WINTHROIP, MASSACHUSETTS.

DRYING APPARATUS.

Application led March 15, 1922. Serial No. 543,937.

To all whom t may concern:

B'e it known that I, OTI's I). RICE, a citizen of the United States. and resident of VVint-hrop, county of Suffolk, State of Mas-V ,cause a current of drying medium to circulate continuously through said closed circuit and over the material to be dried, and means to maintain a reduced pressure in said drying chamber. A drying apparatus of this type is illustrated and described in my Patent No. 1,328,897, Jan. 27, 1929.

minimum the leakage of air throughthe The object of the present invention is to provide a drying apparatus of the abovementioned type which canbe used to dry material in the form of a continuous web or sheet by feeding the web or sheet through said chamber. To feed the web into the chamber involves the provision of an inlet opening or passage leading tothe chamber and through which the web passes, and the delivering of the web from the chamber involves the provision of another opening or passage leading from the chamber and through which the web is discharged. Y

Another object of my invention is to provide a drying apparatus such as above described with means for reducing to the inlet and outlet openings and doing this in such a way as to avoid any possible injury' to the web material passing through said openings, thus providing a drying apparatus which is suitable Jfor drying web Amaterial in the form of paper or cloth.

In order to give an understanding of the 'invention I have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.

In the drawin s, Fig. 1 is a longitudinal. sectional view s owing more or less diagrammatically a .drying apparatus embodyin my invention.

Fig. 2 is a sectionion the line 2-2, Fig. 1. Fig. 3 is a section on the line 3 3, Fig. 1.

Fig. et is an enlarged sectional view taken through one pair of bames.

Fig. 5 is a front View of Fig. 4.

In the drawings 1 indicates a drying chamber in which the material is to be dried and which is constructed so that the drying medium may circulate therein continuously through a closed circuit, and also constructed l so that a reduced pressure may be continuously maintained therein. In the device herein shown the chamber 1 is divided by partitions 2 into a plurality of compartments indicated at 3 and each compartment is construct-l ed to constitute a closed circuit through which a heating or drying medium may be continuously circulated. These compartments are shown -as communicating with each other through openings t formed in the partitions, and 5 indicates the web material which is to be dried, said material extending across each compartment and passing through the openings 4 therein. 6 designates suitable rolls which serve to guide the. web material 5.

The web material 5 thus divides each compartment into two passages 8 and 9, onev -above and the other below the web material, said passages communicating with each other at the ends 7 of the compartments. The passages 8 and 9 communicating at their ends thus form a closed circuit in each compartment through which a heating or drying medium may be continuously circulated as indicated bythe arrows in Fig. 3. This circulation may be caused in any suitable way, as by means of fans 10 which are indicated somewhat diagrammatically. and which may be driven in any usual manner.

llindicates heaters over which the drying medium circulates, said heaters being for the purpose of heating the medium to increase its heating or drying eiiiciency.

Means are provided for maintaining a reducedpressure in each compartment and this may be done by connecting the compartment with one or more suction pipes 12 which lead to a suction apparatus or exhaust device. These suction pipes 12 will preferably be located atl the position in the closed circuit where the circulating medium is coolest, which will usually be in just advance of the heater 11.

With this apparatus as thus far described, the suction apparatus, not shown,

i ment will be continuously circulated therein through a closed circuit and will thus be repeatedly brought in contact with the web material to be dried.

The operation of the apparatus as thus fardescribedy is substantially the same as that set forth in my above-mentioned Patent No. 1,328,897. j

One feature of my present invention relates to a construction whereby the web material may be continuously fed into the drying chamber 1 and subjected progressivelyto the drying action therein, and'also to means for reducing to a negligible quantity the leak-v age of air through the inlet opening or passage through which the web is introduced into the drying chamber.

Another feature of the invention relates to a construction whereby the'` web material may be continuously withdrawn from the drying chamber, and also to means for reducing to a negligible amount the leakage of air into the chamber' through the discharge opening. v c

In the construction herein shown the web 5 is introduced into the chamber 1 through an inlet passage 13, and this passage is pro'- vided with means for progressively 'decreasing the pressure from the outer end thereof at which thev webl enters to the inner end thereof at which.fthe web is .delivered from said passage into the chamber so that at the delivery end thel pressure inthe passage will vary but little from thatin the drying chamber 1.

The drying chamber v1 is also provided with another elongated passage 14 through which the web material is delivered from the drying chamber, and this ,passage 14 is also provided with means for progressively decreasing the ressure therein. from the outer end at which theweb is delivered, lto the'inner end which communicates withK the`` chamber and at which the web enters the passage 14. f

This progressive the passages 13 and 14 is -lierein provided for by employing in each passage a plurality of bales which divide the passage'- into ,separate compartments that, however, 'communicate with each other through a restricted opening of suiiicient width to permitA the web to pass. With this arrangement the pressure in the com artments will be progressively 4descrease from the outer compartment to the inner compartment, and in the inner compartment the pressure will be only slightly greater than that in the drying chamber. Owing to this slight dii'erence of pressure between the chamber and the inner leakage-of air through .the compartments into the' drying'chamber, said leakage Abeing sosmall as not to counteract theaction of thickness. y .is shown in Figs. 4 and 5, wherein the baille change nof pressure in the suction a paratus in maintaining the desired reduce pressure. `These baiies are also constructed so that the'web material may pass between them` 13 both above andbelow the web 4 are partitions 15. Each partition has secured thereto a iexible baille plate, the baile plates secured to the lower partition's being indicated Aat 1 6 and those secured to the upper partitions being indicated at 17. These baille l plates are arranged in pairs, each pair comprising a baille plate above and one below the web 5, and the bailes of each pair converging toward each other to form a relatively narrow throat 18 through which the web 5 passes. The throat has a width slightly greater than the thickness of the web 5 so that the latter may pass therethrough without contacting with the baiies.

MeansV are also preferably provided for adjusting the balles toward and from each other lto accommodate webs of Adifferent One way of accomplishing this 16 is curved backwardlybeyond the throat and the edge 19 thereof is secured to a late 20 extending across the passage 13, an the lbaille 17 is similarly curved away i'romthe throat as shown'at 21 and is secured to aj bar orv late 22 extending across the passage 13. T e bar 20.has at each end' a lug`23 into which is screw-threaded van adjusting screw 24, the latter having a 'reduced upper end 25 whichextends through an' `openmg in a lug 26 extending from the vplate 22.

The upper end of the-adjusting. screw 24v is formed with a collar 27 and a'fspring 28 encircles the 'reduced portion 25 and is confinedbetween,-fthe collar 27 and the lug 26. f

against4 the'under side-of the lug ,26 and Thev` adjusting-serew r hasing this construc- Q Ation will have a shoulder 29 which seats;`

uo the spring 28 will yieldingly hold theifscrew fi in this position. By turning they adjusting screw the lower screw-threaded endlY therel of will be screwed up or downin the lug 23, thus adjusting the width of the throat 18..'

A similar construction is employed in the' discharge passage 14.V

Itwiljl, therefore, be seen that each ofthe passages 13 and 14 is divided into se arate compartments which communicate wit .each

other throu h the restricted throat 18, and

that the we material passes through s/aid compartments and throats successivelyu;y

In the operation of the device the pressure difference between the chamber-1 and the atmosphere will be dividedbetween the separate compartments in the inlet and outlet passages, the pressure in the compart-l ments varylng progressively from the outer to the inner end of the passage. The pressure in the compartment adjacent the inner end will be lowest and will be slightly above that in the drying chamber and the pressure in the compartment at the outer end of the passage will be greatest and will be slightly below atmospheric pressure. There will, of course, be a slight leakage from one compartment to the other and into the drying chamber but the total leakage into the drying chamber will be only that which is due to the difference of the pressure between the innermost compartment of each passage and that of the drying chamber.

In fact the leakage through any throat 18 will be determined by the difference in the pressure on opposite sides of the corresponding baffles.

The leakage of air through the throats 18 has the effect of floating the web through the throat between two air lms, and the presence of these air films protect the web from contact with the bailes.

The delector plates 30 are shown and which may be used if desired and which serve as means to deect the air currents against the web.

The springs 28 have the advantage that they provide yielding throats, which yield or open to permit a thick spot in the web to pass Without breaking the web. f

While I have herein illustrated a selected embodiment thereof I do not wish to be limited to the constructional features shown.

I claim.

1. In a drying apparatus of the type having a drying chamber, means to cause the drying medium to circula-tetherein through a closed circuit, and means to maintain vacuum conditions in said chamber, the combination with a drying chamber having an inlet passage leading thereto, of means to feed web material into the chamber through said passage, and means to reduce progressively the pressure from the outer to the inner end of the passage. y

2. In a drying apparatus of the type having a drying chamber, means to cause the drying medium to circulate therein through. a closed circuit, and means to maintain vacuum conditions in the chamber, the combination with a drying chamber having an inlet passage leading thereto, of means to feed web material into the chamber through said passage, and means dividing said passage into a plurality of compartments which communicate with each other and through which the web passes, whereby the pressure is reduced progressively from the outer to the inner end of the passage.

3. In. a. drying apparatus of the type havinga drying chamber, means to cause the drylng medium to circulate therein through a closed circuit, and means to maintain vacuum conditlons 1n the chamber, the comblnation with a drying chamber having an inlet passage leading thereto, of means to feed web material into the chamber through said passage, and means dividing the passage into a plurality of communicating compartments through which the web passes, the communication between adjacent compartments being in the form of a narrow slit slightly wider; than the thickness of the web passing therethrough, whereby the pressure is reduced progressively from the outer to the inner end of the passage.

4.' In a drying apparatus of the type having a drying chamber, means to cause the drying medium to circulate therein thro-ugh a closed circuit, and means to maintain vacuum conditions in the chamber, the combination with a drying chamber,- of an inlet passage leading thereto, of means to feed web into the chamber through said passage, and means dividing the passage into Ia plurality of communicating compartments through which the webI passes, the communication between one compartment and the next being in the form of a converging throat which is slightly wider at its narrowest point than the thickness of the web passing therethrough, whereby the pressure is reduced progressively from the outer to the inner end of the passage.

5. In a drying apparatus of the type having a drying chamber, means to cause the drying medium to circulate therein through a closed circuit, and means to maintain vacuum conditions in the cham-ber, the combination with a drying chamber having an inlet passage leading thereto, of means to feed web into the chamber through said passage, and means dividing the passage into a plurality of communicating l compartments through which the web passes, the communication between one compartment and thel next being in the form of a converging throat which is slightly wider at its narrowest point than'the thickness of the web passin therethrough, and means to adjust the with of each throat, whereby the pressure is reduced progressively from the outer to the inner end of the paage.

6. In a ldryinlg apparatus of the type having a drying c amber and means to maintam vacuum conditions therein, the combination with a drying chamber having a delivery passage leading therefrom, of means to deliver web material from said chamber through said passage, and means dividing said passage into a plurality of communicating compartments through which the web passes, whereby the pressure is reduced progressively from the outer to the inner end of the passage.

7. In a drying apparatus of the type having a drying chamber and means to maintain vacuum conditions therein, the combinaton with a drying chamber having a delivery passage leading therefrom, of means to deliver web material from said chamber through said passage, and means dividing said passage into a plurality of communi-y cating compartments through which the web passes, each compartment communicating with the adjacent compartment through a.

outer to the inner end of the passage.

8. In a drying apparatus ofthe type having a drying chamber and means to main,

tam vacuum conditions therein, vthe combination-with a drying chamber having an inlet `passage leadin thereto, and a delivery passage leading t erefrom, means to feed web material through the inlet passage through the chamber .and through. the deliv passage,- and means in each passage divi ing it into a plurality of compartments 20 which communicate with each other by means of a narow throat through which the web passes, whereby the pressure is reduced progressively from the outer to the inner end of the passage.

In testimony whereof, I have signed my name to this specification.

OTIS D. RICE.

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