US3254426A - Air-jet dryer for printed material - Google Patents

Description

June 7, 1966 J. K. LAMB ETAL AIR-JET DRYER FOR PRINTED MATERIAL 5 Sheets-Sheet 1 Filed May 14, 1962 FIGM.

I INVENTORS JOHN KLAMB BY EUGENE J.DALEY PMMWM ATTORNEYS June 7, 1966 J. K. LAMB ETAL 3,254,426

AIR-J ET DRYER FOR PRINTED MATERIAL Filed y 14, 1962 5 Sheets-Sheet 2 Z I] 27 1Q 36 'i f FIG. 11?. with 33 i414 25 23 Z2 47 20 77 g 3 42 0 i 72 a l l 3 1 L 5; 2E

FIGJZI.

INVENTORS JOHN K LAMB EUGENE J. DALE) A TTORNEYS June 7, 1966 J. K. LAMB ETAL 3,254,426

AIR-J ET DRYER FOR PRINTED MATERIAL Filed May 14, 1962 3 Sheets-Sheet 5 FIGWI. FIG. EH.

INVENTORS JOHN K.LAMB BY EUGENE J. DALEY ATTORNEYS United States Patent 3,254,426 AIR-JET DRYER FOR PRINTED MATERIAL John K. Lamb, Mariemont, and Eugene J. Daley, Cincinnati, Ohio, assignors to Cardel Electric Co., Inc., Cincinnati, Ohio, a corporation of Indiana Filed May 14, 1962, Ser. No. 194,393 Claims. (Cl. 34-155) the dryer, as distinguished from recirculating substantially solvent-laden air in the system.

A further object of this invention is to provide for a novel orificed or perforated plate and arrangement thereof, which effects a highly uniform and consistent impingement of air upon every portion of a printed sheet as it passes through the dryer without building-up or conjesting the impinged air along the mid-portion of the sheet below the center of the plate.

Another object of this invention is to provide for continuous impingement on the leading edge of a printed sheet as it enters the dryer proper thereby preventing lifting or curling of the sheets edge or edges as a result of internal dryer air eddy currents.

Another object of this invention it to provide for means preventing the impinged air currents to flow towards the ingress slot of the dryer through which clean or fresh air is primarily drawn, and thereby cause a desired rearward air flow through the dryer.

A still further object of this invention is to provide for the suctional flow of clean air to a heating means before impingement thereof upon a printed sheet.

Another object of this invention is to provide for avenues of escape of the spent and solvent-ladened air that impinges on the printed sheet, and to provide for collection and return of the spent air from such avenues for reheating in the circulating system.

Another object of this invention is to provide for the withdrawal of spent air from over a printed sheet whereby a closed system of circulating air is efficiently effected.

Another object of this invention is to provide means to maintain rearward air flow to withdraw or discharge solvent-ladened air from the circulating system to the outside atmosphere.

A further object of this invention is to provide for the continuous movement of a large quantity of air at a high velocity to accomplish more and quicker drying ofa silk screened material than heretofore realized by air-jet or other dryers.

Another object of this invention is to utilize a greater length of a conveyor in the dryer proper thereby resulting in less time to dry a printed sheet at a lower or reduced temperature.

Further objects and advantages will be apparent to those skilled in the art to which this invention pertains, from a reading of the following description of an illustrative embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. I is a plan view of a conveyor means for a dryer embodying the invention, parts of which conveyor means and dryer are broken away;

FIG. II is an elevational view of the dryer, parts of which are broken away to expose various elements thereof;

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FIG. III is a view taken on line III-III of FIG. II;

FIG. IV is a sectional view taken on line 1V-IV of FIG. II;

FIG. V is a fragmentary view of a novel orificed plate included in the embodiment of the invention;

FIG. V1 is a view taken on line VI-VI of FIG. V;

FIG. VII is a fragmentary sectional view of the orificed plate taken on line VIIVII of FIG. V;

FIG. VIII is a fragmentary sectional view taken on line VIIIVIII of FIG. V;

FIG. IX is an exploded view of a portion of the plate shown in FIG. V;

FIG. X is a sectional view taken on line X-X of FIG IX;

FIG. XI is'a perspective view of a partition element of the dryer; and

FIG. XII is a fragmentary sectional view of the position in the dryer of the partition element shown in FIG. XI.

Referringin particular to the drawings, FIGS. I, II, III, and IV disclose a dryer 10 incorporating the preferred embodiment of the invention which includes a plenum chamber 11 into which circulating heated air (as illustrated 'by the rotating arrows in FIG. IV) having a predetermined temperature enters from a furnace or heater 12 which raises the temperature of the air being used. A centrifugal blower or blowers 13 are mounted below a collector pan 15 into which fresh or clean air for the circulating system of the dryer is drawn. Blowers 13 push such air through furnace 12 to plenum chamber '11 where pressure develops as the result of the transmission and detention of heated air therein. Such expanded heated air is thence forced through a plurality of countersunk orifices 16 (FIGS. V and VII) in a novel plate 17 which constitutes the base of plenum chamber 11 and which isolates or completely seals same from collector pan 15 (FIG. IV). A conveyor means 19 is suitably mounted and supported approximately midway in the height of dryer 10, being disposed between plate 17 and collector pan 15 whereby a printed sheet or material 20 advancing on such means through the dryer is capable of being continually and uniformly subjected to streams or jets of freshly heated air which impinge on all portions of the material by being discharged through orifices 16 in plate 17. Such impinging air absorbs and Withdraws ink solvents from printed sheet 20 and carries same away fronrabove the entire sheet without a build-up orcongestion of solvent-laden air thereabove in a novel manner toward and to a pair of air deflectors 21 each mounted below and extending along the entire length of one of sides 22, 23 of plate 17. Deflectors 21 divert spent air towards and into collector pan 15 by smoothly turning about the direction of air flow along the deflectors surfaces, as shown in FIG. IV. An exhausting means 24 (FIG. IV) is located along end side 25 of dryer 10 to discharge the solvent-ladened air from the circulating system of dryer 10. The spent air diverted into collector pan 15 by deflectors 21, together with newly pulled-in air via an ingress slot 26 through which printed sheet 20 is introduced (FIG. III), is drawn directly to blowers 13 and heater 12 for use in plenum chamber 11 before being jetted onto silk screened sheet 20. .It should be noted that the total combined withdrawal of air through both collector pan 15 and exhausting means 24 exceeds at any one time the volume of spent air below plate 17 after impingement on printed sheet 20. stantaneously and simultaneously drawn off into exhaust means 24 with their release from sheet 20 under plate 17 because of an induced s'uctional effect resulting from such excess withdrawal.

Consequently, the evaporated solvents are in Sheet metal housing 27 of dryer is mounted on a frame 30 whose horizontal members 31 are welded or otherwise fastened to and securely resting on a plurality of leg members 32. Channel-shaped side members 31 extend the length of dryer 10. Plenum chamber 11 is disposed in housing 27 by means of fabricating metal sheets as the sides and ends of housing 27 and mounting them securely onto frame 30. A hatch 33 is suitably arranged centrally of the dryer within inclined front side 34 for access to the chamber. An open wall 35 is formed in back side 36 of housing 27 contiguous to plenum chamber 11 and provides for movement of heated air thereinto from heater 12 which is suitably clamped or bolted to side 36.

Plate 17 is securely mounted to frame 30 by means of being bolted to angle members 40, 41 attached to sides 34, 36, respectively, and comprises two symmetrically arranged sections 42, 43 having as a common boundary longitudinal center line or apex 44 of plate 17. Each half 42, 43 is vertically angled upwardly from -a horizontal plane containing center line 44, or in other words, having its apex 44 facing downwardly and extending substantially parallel to the direction of movement of the sheets being dried adjacent plate 17, as is clearly observed in FIG. VI. As a result of sucha V-shaped cross-sectional configuration of plate 17, the space between fiat or horizontally laid sheet 20 on conveyor means 19 and plate 17 increases from center line or apex 44 of plate 17 to each of its sides 22, 23. In the instant embodiment, as shown in FIG. VI, x represents one inch, however, it is to be understood that the V-shaped cross-sectional configuration is not limited to such a small degree, and in a particular model constructed, x may be of a greater dimension if desired. A pair of housing ends 25 and 45 completes the isolation of plenum chamber 11 from the lower portion of housing 27. Each sheet metal end 25, 45 extends from the top of the dryer to a horizontal line immediately above ingress slot 26 and an egress slot 47 formed in the respective ends of the dryer for introduction to and removal of sheet 20 along conveyor means 19.

The V-shaped cross-sectional configuration of plate 17 provides for the accommodation of a volumetric fiow of escaping air which is carried off printed sheet 20 without building up or congesting the space about the longitudinal line 44 of plate 17, in ever increasing spaces to each side of center line 44 and provided by such configuration and the horizontal position of sheet 20. In other words, plate 17 is so disposed that the cross-sectional area of air flow between plate 17 and a sheet or sheets 20 being dried increases in the direction of air flow from apex 44. Printed sheet 20 is dried quickly and at a high productive rate by the method of producing a large volume-of-air movement over the ink with an advantageous reduction in a high degree of heat which heretofore had been necessary in silk screen dryers. Secondly, removing solvent-ladened air from the circulating system of air and from over the mid-portion of a printed sheet, presented a problem, since substantially the air circulating in the system was constantly reused and a quantity of solvent-ladened air always remained over the printed sheet. The novel construction of plate 17 with its defined configuration and the chevron-like pattern of orifices described below provides for an unimpeded avenue of escape towards deflectors 21 and dryer end 25 for the spent air and the evaporated solvents.

A chevron-like pattern of orifices 16 has been incorporated into plate 17 to provide for a highly efiicient drying of sheet 20 as well as providing for an efiicient removal or withdrawal of the continuously impinging air on the printed sheet. As shown in FIG. V, such pattern comprises a plurality of rows of orifices 16 in each half 42, 43, each row beginning at center line 44, or a geometrical extension thereof, and extending towards its respective side of plate 17 at a preferred angle of 25 measured from leading edge 49 of plate 17. Furthermore, as shown in FIG. VII, each orifice 16 is bored and countersunk along an axis perpendicular to the half of plate 17 in which it is located. Preferably, each orifice is spaced 1 from adjacent orifices in the same row, and each row of orifices is preferably spaced three inches from its immediately adjacent rows, such spacing being measured on a line perpendicular to the 25 angled line passing through the center of each orifice in a row (FIG. IX). Such spacing is determined by the volume of air used to dry printed sheets, and is thus dependent upon the static pressure developed in the plenum chamber. The resulting later-ally extending angularly disposed pattern in each half of plate 17 as observed in FIGS. V and IX is one of staggered orifices from one row to the next, viewed over and along a direction parallel to the center line 44 of the plate as it.is scanned from edge 49 rearwardly, and such pattern resembles a chevron-like appearance of orifices across the width of plate 17. The rows of orifices extend continuously along the length of plate 17 to dryer end 25 of plenum chamber 11 but do not, however, extend forwardly to leading edge 49 of plate 17. A marginal area or buffer strip 50 abuts leading edge 49 and separates orifices 16 therefrom. Within buffer strip 50, a series of apertures 51 are spaced at equal intervals across the width of plate 17. As shown by FIGS. V, VIII, and IX, each aperture 51 is bored in plate 17 in a vertical plane parallel to the vertical plane of center line 44, FIG. IV, of dryer 10, the axis of each aperture 51 being directed towards end 25 of dryer 10. Thus, any air discharged through. apertures 51 is directed onto sheet 20 towards end 25 of dryer 10, in contradistinction to the direction of air which is discharged through orifices 16 towards the sides 34, 36 and end 25 of dryer 10 and air deflectors 21. i

As illustrated in FIGS. V, IX and X, blocking means comprising a pair of smaller sized blocking ports 52 is evenly spaced between each row of orifices 16 with each such pair being located substantially along a perpendicular line extending between adjacent rows of orifices and which line passes through at least the first orifice in the row whose first orifice begins adjacent the strip 50. Ports 52 are so bored in plate 17 that the flow of air therethrough forms an air curtain within and along the corridors formed by rows of orifices 16 and not across the rows themselves. Any air thus tending to flow towards bufi'er strip 50 and leading edge 49 of plate 17 is prevented, thereby advantageously being conducive to the overall removal of such air towards deflectors 21 and dryer end 25.

Collector pan 15 is provided below plenum chamber 11 and is adapted to collect air which has been spent on the printed sheet and to draw in clean air as it is pulled into dryer 10 with each printed sheet at forward end 45 through ingress slot 26. Collector pan 15 comprises a sheet metal apron spanning the entire width of housing 27, being secured to the frame thereof in a suitable manner as is customarily used in sheet metal construction and includes an upright side which terminates below ingress slot 26 while exhausting means 24 closes 0E collector pan 15 at the other end of the dryer. A raceway or depression 55 is formed in pan 15 centrally thereof, with fiat level sections 56, 57 extending therefrom to horizontal members 31. Within depression 55, openings 58 are formed, to each of which air returns or ducts 60, 61, 62, respectively, are attached. In the preferred embodiment, ducts 60, 61, 62 are connected to housings 65, 66 of blowers 13 via conduit 63 shown in FIGS. II and III. Housings 65, 66 each contain openings 67, 68, respectively, which are flush with back side 36, and fitted to the lower portion of openings in heater 12. Centrifugal blowers 13 are securely fixed to a shaft 70 disposed in and along the length of conduit 63 and housings 65, 66. Suitable supports, such as standards 71, 72 support shaft 70 in bearings through which the shaft is rotated. A motor 73 is provided to operate blowers 13 by means of a pulley belt connection 74 at one end of shaft 70.

Air deflectors 21 are constructed preferably as an extension of the flat sheet metal constituting collector pan 15 and its level sections 56, 57 (FIGS. III, IV). Such deflectors 21 are directed upwardly along member 31, forming curved deflecting portions 75, 76 immediately contiguous tothe undersurface of plate 17. Thus, spent air from sheet 20 is swept into air deflectors 21 as air is continually discharged through plate 17, onto and from sheet 20. The airs direction is thus diverted laterally of dryer and downwardly toward and into collector pan 15.

Exhausting means 24 is located adjacent rear side 25, below conveyor means 19 (FIGS. II, III) and is so disposed to withdraw the solvent-ladened air spent from impingement on sheet 20 rather than returning same to the circulating system. A sheet metal compartment 81,

having a grilled opening 82, is attached to collector pan 15, spanning the width thereof, and having open grill 82 flush with raceway 55 and level sections 56, 57. A flue 83 is attached to compartment 81 and in which a fan 84 is securely mounted to withdraw vaporized ink solvents through grill 82. A cut off 85 is included in flue 83 adjacent fan 84, to function as an adjustable damper depending upon the full or partial silk screening being performed, i.e., whether an entire sheet has been inked or merely portions thereof by way of print, design, or the like. A suitable motor mechanism (not shown) is used to actuate fan 84 during operationof dryer 10 (FIG. III) in order to discharge the solvent-ladened air into the atmosphere.

As shown in FIGS. XI and X11, between endless conveyor means 19 and within the boundary of egress slot 47 of dryer 10, an obstructing partition 90 is mounted and secured to frame 30 or members 31 by means of a support 91, in order to prevent fresh air from entering dryer 10 from such end. The partition 90 substantially reduces the amount of air to enter egress slot 47 While fiow of air through ingress slot 26 is substantially unhindered from flowing'directly into the circulating system of dryer 10. Such arrangement adds to the efliciency of the dryer upon printed material by ensuring one-direc tional flow of the entire air circuitry.

- Conveyor means 19 for the printed material 20 is preferably constructed as an integral part of dryer 10. However, it should be understood that a suitable endless belt assembly may be adapted to dryer 10. In FIGS. 1 and II, conveyor means or assembly of belts 19 pass through each slot 26, 47 and extend beyond ends 25, 45 of dryer 10, and are mounted on an extension frame 95 welded or otherwise attached to frame 30. The belts rotate about rollers 96, 97, each respectively mounted at the extreme ends of extension frame 95, and are driven by a suitable motor 98 and pulley connection 99 to the roller 96. Pairs of idler rollers 100, 101 may be mounted at convenient points along side members 31, to support belts 19 and the movement thereof.

It should be noted that in a commercial embodiment of the invention, heater 12 contemplates a fire-box radiator-wrap-around type of furnace or other indirect heat exchanger, i.e., one in which the heating source in the furnace does not directly contact the flowing air of the circulating system, however, other type units which raise the temperature of the air would be satisfactory.

In operation of dryer 1t), sheet 20 is introduced onto conveyor means 19 at slot 26. As the leading edge of sheet 20 enters dryer 10 and passes below plate 17, jets of air through apertures 51 stabilize such entry thereby eliminating flutter of the printed sheet. Such blasts of air are directed in the direction in which sheet 20 is moving, the nature and construction of said apertures having been previously described, and forces the sheet to maintain pressure contact with the conveyor or assembly of belts 19. Advancing onwardly, sheet 20 is thence subjected to impingement of air jets through orifices 16 as it proceeds through dryer 20. The totality of air impingement on sheet 20 is uniform about the surface thereof. Because of the nature and construction of plate 17, its orifices 16 and blocking ports 52, the jets of air are carried off laterally and along an air corridor developed or formed between each row of orifices. Spent air passes along each such corridor towards one of the deflectors 21. The impetus which moves the air along such corridors is due to the chevron pattern or directional line of orifices :16. Blocking ports 52 disposed between each row of orifices at buffer strip 50 prevent the movement of spent air towards slot 26 at which point fresh air is being drawn in directly to collector pan 15 by means of blowers 13. The line of apertures 51 also contributes to prevention of spent air flow towards slot 26 in dryer 10.

The V-shaped configuration of plate 17 establishes ever- -increasing spaces above flat sheet 20, through which the air can readily be removed after impingement on sheet 20, eliminating a build-up or congestion of solvent-ladened air over the center of sheet 20 heretofore present in dryers such as disclosed in the Maescher Patent No. 2,907,118. An efficient operation upon silkscreened material is thus effected.

It shouldalso be noted that ducts or openings 60, 6-1, 62 are trapezoidally shaped with the base thereof being the most remote from the blowers 13. In this manner, control of the flow of air from above collector pan 15 to blowers 13 is evenly distributed about deflectors 21 in that the same quantity of air is pulled into blowers 13 from one-half of collector pan 15 as from the other half thereof, thereby providing for withdrawal of all the air over the ent-ire collector pan.

Pursuant to the requirements of the patent statutes, the principle of the invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art to which it pertains, such exemplification including what is presently considered to represent the best embodiment of the invention. However, it should be clearly understood that, within the scope of the appended claims, the invention'maybe practiced otherwise than as specifically described and exemplified herein, by those skilled in the art, and having the benefit of this disclosure.-

That which is claimed as patentably novel is:

1. An improved dryer for printed sheets, said dryer comprising in combination,

a plenum chamber,

a heater contiguous to said chamber,

at least one blower connected tosaid heater,

a collector pan disposed below said plenum chamber,

said blower connected to said pan to withdraw air therefrom and conduct same into said heater,

means to convey printed sheets through said dryer disposed between said chamber and collector pan,

a perforated plate constituting the base of said chamber and having a plurality of laterally extending angularly disposed rows of orifices in each longitudin'al half of said plate and through which jets of air from said plenum chamber are forcefully and uniformly discharged onto the printed sheets moving on said conveying means, I

said plate being V-shaped and disposed with its apex facing downwardly and extending substantially par- 'allel to the direction of movement of the sheets being dried adjacent the plate and also disposed so that the cross-sectional area of air flow between the plate and the sheets being dried increases in the direction of air flow from said apex, whereby said rows of orifices provide avenues of escape for the flow of spent and solvent-ladened air impinging on said sheets and which otherwise would build up over said sheets retarding the drying of said sheets,

air deflectors'situated below and along the sides of said plate to divert the escaping air into said collector pan, and an exhaust means to withdraw and discharge solvent-ladened air from the air circulating system of said dryer whereby the volume of air taken into said plenum chamber for impingement on the printed sheets is substantially fresh.

2. An improved dryer for printed sheets, said dryer comprising in combination,

a plenum chamber,

a heater contiguous to said chamber,

at least one blower connected to said heater,

a collector pan disposed below said plenum chamber,

said blower connected to said pan to withdraw air therefrom and conduct same into said heater,

means to convey printed sheets through said dryer disposed between said chamber and collector pan,

a perforated plate constituting the base of said chamber and having a plurality of laterally extending angularly disposed rows of orifices in each longitudinal half of said plate and through which jets of air from said plenum chamber are forcefully and uniformly discharged onto the printed sheets moving on said conveying means,

said plate being V-shaped and disposed with its apex facing downwardly and extending substantially parallel to the direction of movement of the sheets being dried adjacent the plate and also disposed so that the cross-sectional area of air flow between the plate and the sheets being dried increases in the direction of air flow from said apex, whereby said rows of orifices and configuration provide avenues of escape for a flow of spent and solvent-ladened air impinging on said sheets and which otherwise would build up over said sheets retarding the drying of said sheets, and

air deflectors situated below and along the sides of said plate to divert the escaping air into said collector pan.

3. The dryer of claim 2 in which the collector pan is characterized by having a trapezoidally shaped duct or ducts attached thereto and to said blower whereby all the air in said collector pan under said V-shaped plate is uniformly removed by said blower.

4. In a dryer for printed sheets having a housing through which an endless path of air circulates in combination, a plenum chamber in said housing, a heater, a blower pushing air into said heater from which it emerges into said plenum chamber, a collector pan below said plenum chamber and having at least one duct leading to said blower whereby a circulating air system is established, a perforated plate isolating said plenum chamber from said collector pan, and means to conveyv printed sheets through the dryer below said plenum chamber and above said collector pan, the improvement comprising said perforated plate being characterized by a V-shaped cross-sectional configuration, a plurality of laterally extending angularly disposed rows of orifices in each half of said plate, each row of orifices extending laterally towards a side of said plate at an angle of 25 from the leading edge of said plate, whereby build-up of spent and solvent-laden air over the sheets is eliminated and avenues of escape for such air are provided, a row of apertures adjacent said rows of orifices and disposed in a buffer strip next to the leading edge of said plate thereby preventing curling or lifting of a sheets edge, blocking port means between said rows of orifices at such buffer strip, whereby flow of spent and solventladen air towards the leading edge of said plate is prevented, avenues of escape being provided for the spent and solvent-laden air impinging on the printed sheet along corridors between said rows of orifices to the sides of said plate whereby the printed sheets are efliciently dried at a high rate of productivity.

5. The improvement of claim 4 characterized by an exhaust means adjacent said collector pan, whereby solvent-laden air from impingement on the printed sheet is removed from the circulating path of air in said dryer.

6. In a dryer for printed sheets having a plenum chamber,

aheater,

at least one blower adapted to push air into said heater,

a collector pan below said chamber,

at least one duct connecting said pan to the blower or blowers,

a perforated plate isolating said plenum chamber from said collector pan,

conveyor means for the sheets disposed between said plenum chamber and collector pan,

said plate being V-shaped and disposed with its apex facing downwardly and extending substantially parallel to the direction of movement of the sheets being dried adjacent the plate and also disposed so that the cross-sectional area of air flow between the plate and the sheets being dried increases in the direction of air flow from said apex, a plurality of laterally extending angularly disposed rows of orifices in each half of said plate formed by its apex, an air deflector below each side edge of said plate to direct spent and solvent-ladened air over a sheet being dried and flowing along air corridors formed as avenues of escape between said rows of orifices to said collector pan, and

an exhausting means disposed at the terminal end of said dryer to discharge the solvent ladened air from the dryer.

7. In a dryer for printed material, including a plenum chamber, a heater, a blowerconnected to said heater to convey circulating air to said heater, a conveyor means below said plenum chamber and on which printed material passes through such dryer, the improvement comprising a perforated plate at the base of said plenum chamber and characterized by a V-shaped cross-sectional configuration, a plurality of rows of orifices in said plate, each row extending angularly laterally from the center of said plate to a side thereof, whereby air discharged through said orifices impinge uniformly over the printed sheet passing thereunder, whereby the spent air is conducted from over the printed sheet along corridors formed as avenues of escape between said rows, a series of apertures along the leading edge of said plate directed rearwardly of said dryer adapted to maintain the printed material in pressure contact with said conveyor means and prevent curling of the material, means blocking spent air from flowing towards said apertures and leading edge of said plate, a collector pan below said conveyor means adapted to return spent air to said blower, and deflecting means mounted below said plate adapted to divert the spent air to said collector pan from whence it is recirculated through said blower, heater and plenum chamber.

3. A dryer characterized by claim 7 in which said improvement includes an exhaust means adjacent said collector pan and through which the solvent-laden air is withdrawn from the circulating system of said dryer.

9. The dryer of claim 2 characterized by each row of orifices being staggered relative to its immediately adjacent rows of orifices, a series of apertures across the width of said plate between the leading edge of said plate and the pattern of rows of orifices whereby air discharged through said apertures prevents flutter of a printed sheet introduced into said dryer, and blocking means between each rows of orifices adjacent said apertures conducively directing the flow of spent air along the air corridors formed as avenues of escape for such air to said deflectors.

10. In a dryer for printed sheets having a housing through which an endless path of air circulates, a plenum chamber in said housing, a heater, a, blower for conducting air to said heater from which it is transferred to said chamber, the improvement comprising a collector pan below said plenum chamber and connected to said blower whereby a circulating air system is established, a perforated plate of V-shaped cross-sectional configuration isolating said plenum chamber from said collector pan, means to convey printed sheets through ingress and egress slots of the dryer below said plenum chamber and above said collector pan, air deflecting means mounted below said chamber adapted to divert circulating air into said collector pan, said perforated V-shaped plate having a pattern comprising a plurality of staggered rows of orifices in each half thereof each row extending diagonally along each half of and from the center of said plate to its respective side thereof, a series of apertures disposed across the width of said plate between the leading edge thereof and said pattern and having their axes through said plate directed towards the terminal end of References Cited by the Examiner UNITED STATES PATENTS 2,558,338 6/1951 Clements 34-216 2,821,030 1/1958 Bogaty 34236 2,907,118 10/ 1959 Maescher 34-155 3,077,675 2/1963 Dickens 34122 3,089,252 5/1963 Daane 34160 WILLIAM F. ODEA, Primary Examiner.

NORMAN YUDKOFF, Examiner,

A. D. HERRMANN, Assistant Examiner.

Claims (1)

1. AN IMPROVED DRYER FOR PRINTED SHEETS, SAID DRYER COMPRISING IN COMBINATION, A PLENUM CHAMBER, A HEATER CONTIGUOUS TO SAID CHAMBER, AT LEAST ONE BLOWER CONNECTED TO SAID HEATER, A COLLECTOR PAN DISPOSED BELOW SAID PLENUM CHAMBER, SAID BLOWER CONNECTED TO SAID PAN TO WITHDRAW AIR THEREFROM AND CONDUCT SAME INTO SAID HEATER, MEANS TO CONVEY PRINTED SHEETS THROUGH SAID DRYER DISPOSED BETWEEN SAID CHAMBER AND COLLECTOR PAN, A PERFORATED PLATE CONSTITUTING THE BASE OF SAID CHAMBER AND HAVING A PLURALITY OF LATERALLY EXTENDING ANGULARLY DISPOSED ROWS OF ORIFICES IN EACH LONGITUDINAL HALF OF SAID PLATE AND THROUGH WHICH JETS OF AIR FROM SAID PLENUM CHAMBER ARE FORCEFULLY AND UNIFORMLY DISCHARGED ONTO THE PRINTED SHEETS MOVING ON SAID CONVEYING MEANS, SAID PLATE BEING V-SHAPED AND DISPOSED WITH ITS APEX FACING DOWNWARDLY AND EXTENDING SUBSTANTIALLY PARALLEL TO THE DIRECTION OF MOVEMENT OF THE SHEETS BEING DRIED ADJACENT THE PLATE AND ALSO DISPOSED SO THAT THE CROSS-SECTIONAL AREA OF AIR FLOW BETWEEN THE PLATE AND THE SHEETS BEING DRIED INCREASES IN THE DIRECTION OF AIR FLOW FROM SAID APEX, WHEREBY SAID ROWS OF ORIFICES PROVIDE AVENUES OF ESCAPE FOR THE FLOW OF SPENT AND SOLVENT-LADENED AIR IMPINGING ON SAID SHEETS AND WHICH OTHERWISE WOULD BUILD UP OVER SAID SHEETS RETARDING THE DRYING OF SAID SHEETS, AIR DEFLECTORS SITUATED BELOW AND ALONG THE SIDES OF SAID PLATE TO DIVERT THE ESCAPING AIR INTO SAID COLLECTOR PAN, AND AN EXHAUST MEANS TO WITHDRAW AND DISCHARGE SOLVENT-LADENED AIR FROM THE AIR CIRCULATING SYSTEM OF SAID DRYER WHEREBY THE VOLUME OF AIR TAKEN INTO SAID PLENUM CHAMBER FOR IMPINGEMENT ON THE PRINTED SERIES IS SUBSTANTIALLY FRESH.

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