US2002720A - Apparatus for drying sheet material - Google Patents

Description

May 28, 1935.

' R. M. SMITH APPARATUS FOR DRYING SHEET MATERIAL Filed April 13, 1955 Patented May 28, 1935 UNITED STATES PATENT OFFICE Claims.

The present invention relates to drying of inks to prevent ofl-setting in steel and copper plate printing, and more particularly to the printing of separate sheets, envelopes, and the like, where 5 it is difficult to handle such a large number of individual sheets.

One object of the improved dryer is to reduce the space required for the drying process by providing an oven having a series of endless conveyors upon which the sheets are'conveyed and subjected to a medium of ozone.

Another object of the present invention is to facilitate the drying. The time required for the drying of inks in this type of work has always been a handicap to the trade.

With these and other objects in view which will appear hereinafter, the present apparatus was invented. The several novel features in its preferred form will be more fully described in the accompanying drawing in which like numerals are employed to designate like parts throughout the same:

Fig. 1 is a horizontal plan view having a side of the oven removed.

Fig. 2 is an end view with the end plate re-' moved.

' Fig. 3 is a front view of the sheet carrying elements of the upper conveyor.

Fig. 4 is an end view of Fig. 3. v

Fig. 5 is a top view of the feeding mechanism.

Fig. 6 is a longitudinal view of the sheet transferring roller I0.

Fig. '7 is a front view of the perforated plate for discharging ozone. a

Fig. 8 shows a driving means for the dryer.

Fig. 9 is a diagrammatic view of the means for operating the various conveyors.

The invention therefore, includes a rectangular oven l. A conveyor 2 is provided in the upper portion of the oven for holdingeach individualsheet separately for a predetermined length of time. This conveyor 2 is supported upon the rollers 3 and 4 positioned one at each end of the oven. Secured to each end of the rollers 3 and 4, are

' sprockets 5, 5' and 6, 6' for supporting a conveyor chain 1. The links of the chain are provided with projections 8 through which a triangular or other shaped bar II is secured for rigidly supporting the sheet carrying elements 9. The sheet supporting element is formed of a number of parallel bars I2, one end being rigidly secured to the bar II and its other end being free. A support i3 is provided between the free and fastened ends to increase the steadiness and rigidity of the carrier. At the free end of the carrying element the outer portion of the parallel bars are turned at right angles to the front and so distanced that they form a closed pocket 20 at the free end with the adjacent carrier. The portion of the pocket adjacent the conveyor chain 1 being open. Adjacent this opening a number of small belt conveyors are supported by the rollers 3 and Ill. These rollers are provided with grooves I4 and 15 for the purpose of guiding the belts. The function of which is to support the sheets on the first half of the travel of the upper conveyor. The sheets are transferred from the upper half of the conveyor to the lower half when they pass tlfe roller Ill. The projections 3| located on the roller I0 are so synchronized that the sheets will drop into an appropriate pocket on the lower half and be moved again toward the front part of the oven. The outer portion of sheet carrying element 9 when in downward position are preferably supported by conveyor belts l6 suspended between the pulleys I1 and IS. The roller I8 is also provided with projectors l9 similar to those on roller II) which are also synchronized with the sheet carrying element 9 for aiding the removal of the sheets from the upper conveyor.

A rake 2| is rigidly secured to the oven wall and positioned above the front end of the lower conveyor 22 to release the sheets from the upper conveyor. The conveyor 22 extends between the pulleys 23 and 24 and supported along its undersurface by the member 25. This conveyor is regulated to move at a slower rate of speed than the upper conveyor so that the sheets are arranged in a staggered or piled position.

The feeding mechanism is shown as having a frame 26 supporting a pulley 21 with extended arms 28, these arms extend in between the free ends of the parallel bars I2 best shown in Fig. 3 for the purpose of delivering the sheets upon the carrying elements 9. The arms 28 are provided with small pulleys 29 at their extreme end for lessening the friction of the belts which are operated by pulley 21. Two of these belts 32 and 33 are shown in position in Fig. 5. The frame is secured to the even by any convenient means and ,as shown in the drawing the frame is riveted to the front plate 24. The feeding means may be operated either directly from the press by a belt connected to pulley 35 or, may be driven by separate motor.

The oven is provided with an ozonizer 36 and a fanv 31 and a heating element 38. The fan and heating element are separately controlled, each may be used independent of the other or in combination.- The ozone is exhausted out through the top of the ozonizer at 3 9 and out through the conduit 40 to the rear of the oven and through the perforated plate 30. A bafiie plate 4! is provided at the front of the oven and adjacent the feed opening to direct the ozone toward the conveyors.

The dryer is preferably operated by a ratchet movement taken from the press and so synchronized that the sheet carrying elements 9 will be positioned to receive the printed sheet from the feeding means. The feeding means consists of a ratchet wheel 42 which is secured to the shaft 43 carrying the roller 3. A bar 44 is provided to be operated by the press, one end of which carries a pawl 45 for engaging the teeth of the wheel 42 the other end attached to the press where it can be conveniently oscillated. The movement of the conveyor may be regulated by shortening or lengthening the stroke of the bar 44.

Fig. 9 shows diagrammatically the arrangement of the drive chain 46.

- The roller 3 must move in the direction of the indicating arrow. Roller [8 must move in an opposite direction to roller 3 and approximately at the same speed as this conveyor as previously pointed out is used to support the sheet carrying elements 9 in their downward position. The roller 23 must move in the same direction as roller 3, but at a slower rate of speed to provide for piling the sheets upon the lower, conveyor. The size of this drive wheel may be regulated at whatever size is suitable under the circumstances of each particular case.

In operation, ozone is generated in the ozonizer 35 and actuated either by the heating element 38 or by the fan 31 or both and circulated up through the forward portion of the oven and toward the rear. The fan being located near the bottom of the oven draws the ozone from the upper rear down through the conveyors carrying the sheets and under the plate 56 and over the humidifiers 48, sending the same through the ozonizers again to be recharged. By this method only a minimum amount of the ozone is allowed to escape from the oven.

When the oven has become sufliciently ozonized the drying process may begin. Thesheets are conveyedby the feeding'means upon one of the sheet carrying elements, the bar 43 is oscillated causing the conveyor to be moved sufficiently to place in position another sheet carrying element and so this operation continues. As the sheets move along the upper portion of the upper conveyor they are supported by belts positioned between the conveyor links I and on the same horizontal line therewith operating in the grooves l4 shown in rollers 3 and grooves I5 shown in roll- ,er in. The roller l0 with the aid of the projec tions 3| cause the sheets to be released from the upper portion of the upper conveyor and dropped to a correspondent lower position of the upper conveyor, whereby the sheets move front of the oven.

Opposite the roller I 0 isca perforated hollow plate 30 which delivers a blast of the ozonized medium upon the printed side of the sheet at the same time so directed as to facilitate the movement of the sheet toward the lowerportion of the conveyor.

As the sheets approach the front end of the oven on their return trip the projections l9 secured to the roller I8 prevent the sheets from crowding and allows the rake 2| to disengage the sheets from the conveyor in proper order. After the sheets are disengaged they slip down the intoward the clined rack off on to the lower conveyor 22 and are conveyed again' through the oven and out through the discharge opening 49.

By causing the medium within the oven to be continually circulated the escape of ozone is mini- 'mized, thus, preventing the obnoxious odor created by the escaping ozone and at the same time conserving the unused ozone by using over again the partially ozonized medium.

The apparatus is so constructed that the sheets enter the dryer and are supported separately in racks in which the ink is not in contact with any portion thereof due to the angle of the supporting members l2. The sheets are conveyed the length of the oven and transferred to a corresponding lower rack returning again to the front portion of the oven by which time the ink has acquired enough hardness to prevent offsetting by the weight of the few sheets that are carried stacked upon the lower conveyor 22. The sheets will still be subjected to the drying process on the lower conveyor and will be sufficiently dry for use when discharged from the oven.

While I have described my invention, referring to certain details of construction as well as form of the same, it is for the purpose of illustration only, and I do not wish to be limited thereto except as may be pointed out in the following claims.

Having thus described my invention, what I claim is:

1. A drying oven consisting of a container having supported within its upper portion a horizontal conveyor, said conveyor having means thereon for forming individual pockets on its upper and lower horizontal sections, means at one end of said container for delivering printed sheet material upon said upper pocket forming means,

means adjacent the other end for transferring the printed sheets from the upper pockets to the lower pockets, consisting of a rotating member located between the said pockets having means thereon for engaging the said sheet in the upper pocket and releasing them into the lower pockets, means at the forward end of the container for removing the sheets from the lower pockets consisting of a rotating member having means thereon for timing the opening of the said lower pockets, a releasing member rigidly secured to said container and inclined downwardly for disengaging the sheets from the said lower pocket, a second conveyor positioned beneath the upper conveyor and adapted to operate at a relatively lower speed for receiving said sheets from the lower pockets whereby the sheets will be deposited upon the said conveyor in overlapping position, and means for delivering the sheets out of the oven.

2. A drying oven consisting of a rectangular container having supported within its upper portion a horizontal conveyor, said conveyor having means thereon for forming a plurality of individual vertically inclined pockets on its upper and lower horizontal sections, means at one end of said container for delivering an individual.

printed sheet upon said upper pocket forming means, means adjacent the other end for transferring the printed sheets from the upper pockets to the lower pockets which consists of a rotating member positioned between the said closed pockets having means thereon for engaging the sheet conveyor and adjacent the'forward end of the container for removing the sheets from the lower pockets consisting of a rotating member having means thereon for regulating the opening of said pockets, a releasing member rigidly secured to the said container and inclined downward for disengaging the sheets from the said pockets, a second conveyor positioned beneath the upper conveyor and adapted to operate at a relatively lower speed for receiving the sheets from the said releasing member whereby the sheets are collected upon the said lower conveyor in overlapped position, means for generating and circulating ozone .within the container and means for conveying the printed sheets out of the rear end of the said container.

3. A drying oven consisting of a container having supported within its upper portion a horizontal conveyer, said conveyer having means thereon for forming individual pockets on its upper and lower horizontal section, means at one end of the said container for delivering printed sheet material upon said upper pocket forming means, means located along its horizontal portion adjacent the other end for transferring the said sheets from the upper pockets to the lower pockets, means at the forward end of the container for removing the sheets from the lower pockets, comprising of means for regulating the opening of the pocket and means for'releasing the sheets from the said pockets, a second conveyer positioned below the upper conveyer and adapted to operate at a relatively lower speed for receiving the said sheets from the lower pockets, whereby the sheets will be deposited upon the said conveyer in overlapping position, and means for delivering the sheets out of the oven.

4. A drying oven consisting of a container having supported within its upper portion a horizontal conveyor, said conveyor having means' transferring the printed sheets from the upper pockets to the lower pockets, consisting of a member located between the pockets having means thereon for engaging the said sheets in theupper pocket and releasing them into the lower pocket, means at the forward end of the container for removing the sheets from the lower pockets, a second conveyor positioned beneath the upper conveyor for receiving the sheets and means for delivering the sheets out of the oven. 7

5. A drying oven consisting of a container having supported within its upper portion a horizontal conveyor, said conveyor having means thereon for forming individual pockets on its upper and lower horizontal sections, means at one end of the said container for delivering printed sheet material upon the said upper pocket forming means, means adjacent the other end for transferring the printed sheets from the upper pockets to the lower pockets, means at the forward end of the conveyor for removing the sheets from the lower pockets, consisting of means for regulating the timing of the opening of the pockets and means for disengaging the sheets from the said lower pockets, a second conveyor positioned beneath the said sheet disengaging means for receiving the said sheets and means for delivering the sheets out of the oven.

RUSSELL M. SMITH.

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