US2120205A - Method of and apparatus for drying wood veneers - Google Patents

Description

June 1938- e. R. MEYERCORD 2,120,205

METHOD OF AND APPARATUS FOR DRYING WQOD VENEERS Filed Sept. 12; 1936 4 Sheets-Sheet 1 $4M -5 Q J June 7, 1938. MEYERCQRD 2,120,205

METHOD OF AND APPARATUS FOR DRYING WOOD VENEERS Filed Sept'. 12, 1936 4vSheetsSheet 2 I June 1938. G. R. M EYERCORD IETHOD OF AND APPARATUS FOR DRYING WOOD VENEERS Filed Sept. 12, 1936 4 Sheets-Sheet 5 June 7, 1938. e. R. MEYERCORD METHOD OF A ND APPARATUS FOR DRYING WOOD VENEERS Filed Sept. 12, 1936 4 Sheets-Sheet 4 Patented June 7, 1938 UNITED STATES METHOD or AND APrAnA'rUs Fort name woon VENEERS George R. Meyercord, Chicago, Ill., assignor to Meyercord Compound Lumber Company, a cor-' poration of Alabama Application September 12, 1936, Serial No. 100,520

" 7 Claims.

Wood veneers areproduced from logs by peeling the veneers from the logs while the latter are saturated with moisture, that is, while the logs are soaking wet. The veneers must then be dried 5 until the moisture content is greatly reduced. In

drying, the wood shrinks across the grain; apparently no appreciable shrinking taking place until the moisture content has been reduced to about 21 percent, and the shrinkage thereafter l occurring, roughly speaking, at the rate of about one-third of .one percent of the width of the sheet for each reduction of one percent .in the moisture content. Thus, assuming a sheet of veneer to have a width of 100 inches across the grain and to contain moisture in excess of 21 percent, no appreciable shrinkage, during drying, occurs, until the moisture content has been reduced to about 21 percent. If the drying of the veneer be then continued, it gradually shrinks.

20 If the drying is carried out until the moisture content is reduced to 6 percent, for example, the shrinkage amounts to approximately inches, so that the sheet is now only 95 inches wide.

Veneers may be air dried or dried in kilns. The

drying of veneers so that they will remain fiat and will not split or check, except by comparatively expensive processes, has always been difficult, and so far as I know, no satisfactory solution 40 vented, by the presence of adjacent areas or sections that are still relatively wet. Drying in the usual way leaves the veneer in a more or less distorted condition, instead of flat, thereby making the laying up of veneers in the manufacture of plywood more difficult than if the veneers were flat; and it also produces considerable variations in the width of a sheet of veneer atdifierent points throughout the lengthgof the sheet, necessitating trimming of the veneer before it be- 50 comes part of a panel assembly. There are often large knots in sheets of veneer which, while ren-,

dering the veneer unsuitable for use as facing plies, are not objectionable when appearing in interior or core plies. However, in ordinary drying, these knots often become loose and fall out. In that case, strips each at least as wide as a knot hole and extending across the entire length of the sheet must be cut out of the sheets to permit them to be used even as interior plies. This occasions waste of material and added expense in the manufacture of the veneers themselves, and necessitates the assembling and taping together of a plurality of narrow pieces of veneer, instead of a single wide sheet, in making an assembly of veneers. for a plywood panel. In short, the problem of successfully drying large quantities of veneer at a low cost has been so serious as to constitute an important factor militating against the feasibility of commercially producing thick inexpensive plywood panels.

The object of the present invention is to make it possible to dry large numbers of large sheets of wood veneers at a low cost, and in such a manner that each sheetremains flat, of approximately uniform' width throughout its length, without loose knots if there be knots in the sheet and, generally, in a sound condition.

In carrying out my invention I dry the veneer while it is unconstrained, although it may be lightly held in a flattened condition, and while exposing to the drying air a surface area which, for all practical purposes, comprises the total area of its two faces; so that my invention may be viewed in one of its aspects as comprising a novel process whereby large sheets of woodveneer are caused to dry in a natural manner.

It is not sufficient that the veneer be somehow held in a flattened condition with its broad faces exposed to a drying medium, but the veneer must be supported in such a manner that no forces are set up, during shrinking, that produce the di-fliculties above noted. I therefore stand the veneer on edge, with the grain extending horizontally. Then, when the veneer shrinks, it is in the vertical direction. If, during the drying, the veneer is not constrained, so that the effect of gravity may be utilized, the contraction will be entirely in the downward direction; the lower edge of a sheet of veneer remaining stationary and spaced points along a vertical line moving downwardly through distances varying directly with their respective distances from the lower edge of the sheet. During drying,'gravity actually exists in the prevention of cracking, because it is always acting in the direction in which movement of the wood must occur, during shrinking, if no cracks are to open.

Veneers will not stand upright of their own accord. In peeling and slicing veneers from the log or flitch, the cutting is done by means of knives which make sharp bends in the veneers as the latter leave the log or fiitch. This tends to fracture "the wood on the side next to the log.

This results in a weakening of the veneers on one veneers in upright position, with the grain extending horizontally and so nearly unconstrained that they are compelled to settle under the action of gravity when subjected to currents of drying air or the like that sweep over their broad faces.

In order that the cost may be kept low, it is necessary that the manner of handling the veneers up to the time that they. are dried and, preferably, up to the time that a preliminary or other gluing of veneers into panels, must be such that little labor is required and that no appreciable breakage of veneers will result. Therefore, viewed in certain of its aspects, the present invention may be said to have for its object to produce a simple and novel method of drying and handling large sheets of wood veneer up to the point where gluing operations are to begin; and, also, simple and novel apparatus by which my new method is made possible or, at least, is greatly facilitated.

In carrying out my invention, I provide numerous panel-like racks, so devised that when two of them are placed together, they form a wide, high, shallow cage in which a single piece of veneer may be contained in a substantially flat condition. Drying air therefore has ready access to all parts of the superficial area of each sheet of veneer. These racks are stood upright, each pair in contact with adjacent pairs on opposite sides thereof. The veneers are so placed in.the cages that the grain is substantially horizontal, and the drying air is caused to flow in the. vertical direction across both faces of each sheet. With this arrangement, if the drying be not uniform throughout the height of a sheet standing on edge, no splitting or checking results, because the moisture content will usuallybe approximately uniform across the entire horizontal length or width of the sheet for any given elevation above the lower edge of the sheet. Consequently, since the grain of the wood is horizontal, somewhat uneven drying does not result in splitting or checking of the veneer. Trucks, each adapted to carry and transport a large number of pairs of racks, standing on edge, are preferably provided; provision being made to permit the racks to be swung about their lower edges through small angles, in the manner of the leaves of a. book.

A truck full of racks may be filled with veneers by simply wheeling the truck under the end of a conveyor or slide from which sheets of veneer may be dropped edgewise into open cages ready to receive them. In other words, the first pair I swung over in closed relation to its mate, the first rack, leaving a top opening between the inner rack of the first pair and. the next rack.

The second sheet is deposited in this second opening, and the third rack is then swung over against the second, providing a top opening between the third and fourth'racks. The truck is edged along, as conditions require, to facilitate the insertion of veneer sheets between each adjacent pair of racks of the entire group or series.

Therefore, viewed in one of its aspects, the present invention may be said to have for its object to produce a simple and novel open-work container adapted to house a single large sheet of wood veneer in such a manner that air or other gaseous drying medium caused to flow along opposed sides of the container will effectively reach all parts of the faces of the sheet of veneer located therein.

A series of loaded trucks may be wheeled into a suitable tunnel-like dryer so equipped that when heated air is forced in at one end, it will zigzag up and down through the veneers, finally passing out at the opposite end of the tunnel. By properly regulating the conditions, the veneers may be eifectiveiy dried without splitting or checking.

Upon removal of the trucks from the dryer, each truck may be unloaded, the veneers being placed in stacks or bundles and the racks transferred to an empty truck, if desired, which latter truck is then ready to receive a new charge of veneers to be dried. At the time of removing the dried veneers from a truck, they may be sorted, according to grade or quality, so that no further handling of individual sheets will be required until individual veneers are assembled as 1 through a drying kiln, showing more or less diagrammatically one type of kiln construction and a row of loaded trucks filling the same; Fig. 2 is a section on line 22 of Fig. 1; Fig. 3 is an elevational view of one of the open-work racks, sections extending transversely of the same being omitted to shorten the height of the view? Fig. 4.

is an edge view of the rack, on the same scale as Fig. 3; Fig. 5 is an edge view of two racks placed together with a sheet of wood veneer positioned between the same, only upper and lower fragments of the assembly being illustrated; Fig. 6

is a perspective view of a fragment of a rack composed largely of wood; Fig. 7 is a perspective view of one corner of the rack illustrated in Figs. 3, 4 and 5, on a smaller scale than Fig. 5; Fig. 8 is a view similar to Fig. '7, showing a much smaller fragment, and illustrating a means for temporarily clamping a sheet of veneer to the rack; Fig. 9 is a diagrammatic view illustrating a truck loaded with racks or veener holders which are being filled with veneers from a delivery table; Fig. 10 is a perspective view showing diagrammatically a loaded truck and portable beds or bases in the proper positions to begin unloading of the filled truck and the stacking of veneers in assorted lots; Fig. 11 is a top plan view of one of the trucks, the stakes being omitted at the side which is at the bottom of the drawing; and Figs. 12 and 13 are sections taken respectively on line l2-l2 and I 3l3 of Fig. 11, all of the stakes being shown.

being about a foot.

The present invention depends upon the ability to support many large sheets of wood veneer in a comparatively small space, in a manner to leave the veneers free to contract while supporting them so that heated air may be caused to flow over and come in contact with the entire-area of each face of each sheet. This may be accomplished by providing suitable holders such as shown, for example, in Figs. 3-8. Each holder or container consists of two open-work panels which, when placed face to face, are spaced apart a distance slightly greater than the thickness of the veneer to be received thereby. If it be desired to construct these panels or racks from metal, each panel may comprise a series of parallel thin, fiat metal bars I, I set on edge and connected by suitable transverse pieces. In the arrangement shown, the bars are connected together by cross wires 2, 2 welded to the bars. In an actual panel that may be 6 or more feet wide and perhaps 10 or more feet high, the bars I, which are intended to be vertical in the ordinary use of the panels, may be of steel, about three-quarters of an inch wide and one-twentieth of an inch thick, the spacing between the bars The spacing between the wires in such a construction may be less than that between the bars. The two bars at the sides of the panel may be stiffened, each by a flat bar 3 set on edge against the outer face of the side bar and welded to the latter; each side bar thus being, in effect, a T-bar. Each panel or rack has thereon two spacing elements 4 and 5 extending across the entire width thereof from one side bar to the other and welded to both side bars and to the intermediate vertical bars; the spacing element 4 being on one face close to the top of the rack and the element 5 being on the opposite face or side of the rack and close to the bottom. Therefore, when two of these racks are placed together, face to face, they are held apart a distance equal to the thickness of the spacing elements or bars which-then form top and bottom walls for a shallow chamber extending throughout the width and almost throughout the entire height of the assembled racks. If the veneerto be dried is about one-seventh of an inch thick, the spacing bars or elements may be about a quarter of an inch thick, so that when a sheet of. veneer, such as indicated at A in Fig. 5, is placed in the chamber between two racks, it is not gripped or clamped and, at the same time, is held upright and must remain substantially fiat. The veneer is placed with the grain of the wood running crosswise of the rack, namely horizontally, so that end grain appears in the vertical edges as indicated in Fig. 5.

It will be seen' that because the vertical bars I are very thin, they could not cover any substantial surface area of a sheet of veneer even if in contact therewith throughout their lengths. However, the contact between the veneer and the bars of the cage in which the veneer finds itself is at distributed points only, so that the total surface area actually covered by .the bars is negligible. Also, the open-work .construction just described does not interfere to any appreciable extent with effective contact between currents of drying air flowing past a pair of cooperating racks in the general plane of the latter and the sheet of veneer lying between the racks.

If desired, .each sheet of veneer may be clipped lightly to one of the racks between which it lies, thereby to facilitate the subsequent handling of the veneer. This will usually not be done until just prior to removing the dried sheet from between its racks. Thus, in Fig. 8 I have illustrated a clip 6 in the form of a strip of. flat spring metal bent into U-shape; the size of the clip being such that it may embrace one of the edge flanges 3 of the rack and an adjacent marginal portion of the piece of veneer A. Several narrow clips or a clip that is made from ,a long strip folded along a longitudinal line may be employed. When the veneer is clipped to a rack, the veneer will be carried along with the rack when the latter is swung from a vertical into ahorizontal position, instead of collapsing as might otherwise be the case.

The racks may of course be constructed in a variety of ways. In Fig. 6, for example, there is illustrated a fragment of a rack in which the vertical bars I and the transverse spacing bars 8 are composed of wood; the vertical bars being tied together with cross wires 9, corresponding to the wires 2 in the other. construction. The upright bars are also shown as comprising two half-bars lying flat on each other and secured together. This permits the wires to be laid against one set of half-bars and to be secured when the other set of half bars are laid on and fastened to their mates. The upright bars 'are provided on the sides thereof with simple contact devices which are adapted to press lightly against the veneer and'hold it so that it will not lie flat against the faces of the vertical bars which may be regarded as comparatively broad even though they may be only an inch or so wide. tact devices may be simple wires I0 extending longitudinally of the bars and secured thereto at The work These con- Veneers to be dried are preferably inserted in racks already in position on a truck or the like, thereby facilitating and simplifying the handling of the veneers and racks and making it unnecessary to handle individual units again until after the drying has been completed. In Figs. 11-13, there is illustrated a simple form of truck suitable for my purpose. The truck comprises a low openwork bed or body on which the racks may be stood on edge, andwhich permits air to pass vertically through the same and over the surfaces of the veneers thereon. In the arrangement shown, the body of the truck consists of a rectangular wooden frame l3 spanned by a series of longitudinal sills l4 and provided with suitable wheels I5. A pair of diagonal brace rods l6 keeps the frame in its rectangular form. The sills II are preferably spaced the same distance apart as are the upright bars of the racks, so that when arack is placed on the truck its upright bars will all rest directly upon the truck sills. To facilitate proper locating of the racks on the truck and prevent accidental lateral displacement sufficient to cause the bars to slip oif the sills, some of the sills may have steel strips II, or thin plates fastened to the sides thereof and projecting slightly above the upper the grooves or channels produced by the elements l1 and the rack will thereafter be prevented from shifting too far in the plane thereof.

The truckis shown as having upright stakes l8 at its four corners. The upper ends of the stakes at the front end of the truck are connected together by a cross piece l9 as are also the stakes at the rear. The lower ends of the stakes are fitted into suitable pockets 210, so that they may be lifted out at will. Furthermore, either the stakes or the pockets, or both, are so shaped that when the stakes of either unit are set into the pockets in one position, they stand upright, whereas, upon turning the unit around and inserting the stakes in the pockets, the stakes are caused to be inclined upwardly and outwardly. In the arrangement shown, the lower end of each stake has on one side a face parallel with the length of the stake, and on the opposite side, a face 22 that lies at a small angle to such axis. These are the faces that engage either with the outer surface of the ends of the truck body or with corresponding vertical surfaces in the pockets, and I am thus enabled to cause the stakes to stand upright or in slightly inclined positions.

The trucks are made long enough to receive, say, racks, thereby permitting each truck to be loaded with 49 sheets of veneer. The filling of the racks upon a truck may be accomplished in the manner diagrammatically illustrated in Fig. 9. The masses marked B and C in Fig. 9 are intended to represent two groups of racks, the group B having already received a filling of veneer sheets, while the racks of the group C remain empty. It will be seen that the stakes, on

the truck are in their inclined positions so that the racks may be swung through limited angles in the manner of the leaves of a book. In order to continue the filling of the racks, beginning at the point to which the filling has proceeded in Fig. 9, I simply insert between the two rack groups B and C a sheet of veneer and then swing the lefthand rack of the group C toward the left and thus form with the righthand rack of the group B a cage in which the sheet. of veneer is housed. Another sheet of veneer is then lowered into the gap between the two'groups of racks and another rack of the group C is swung over to join the racks of the group B; this processbeing repeated until all of the racks are filled.

Since the sheets of veneer which are being handled are very large, it is advisable that each sheet be delivered from some overhead support below which the truck may be brought and moved step by step so as always to keep what may be termed the jaw into which the veneer is to descend directly in the path of the descending veneer. In the arrangement shown, the support for the individual sheets of veneer is simply a wide, smooth runway 23, the end of which is curved downwardly on I a comparatively large radius. The veneer is fed along this runway, with the grain running crosswise. 'As the advance edge of the veneer reaches the downwardly curved portion of the runway, its flexibility permits it to follow the curvature of the latter so that when the veneer passes beyond the edge of the runway, it is pointing straight down and may therefore be guided into place on the truck without difllculty.

The veneers are dried while on the truck, as will hereinafter be described, and the truck is then unloaded. The operation of unloading the. truck is preferably carried out in such a manner that the sheets of veneer lie in horizontal positions at the time of their removal from the racks. In Fig. 10, there is illustrated the preferred method of unloading. The trucks of course run upon rails because their loads are heavy. Therefore, a truck loaded with racks B filled with dried veneers is run along therail system 24 to the unloading point, and a second empty truck is brought up close to it. The stakes on the sides of the two trucks that are toward each other are removed. Blocks are placed under the wheels of the trucks, or the trucks are otherwise temporarily secured in such spaced relation to each other that the horizontal distance between the lower end of the first rack on the loaded truck, which is the righthand rack in Fig. 10, is spaced apart from the standing stakes on the empty truck a distance equal to the height of the rack. Therefore, the righthand'rack in Fig. 10 may be swung down, its two upper corners describing the arcs represented by the broken lines D, D, until it lies flaton the body of the empty truck. The sheet of veneer between this rack and the next rack in the series is carried along with the first rack during this downward swinging movement. 'It may be held to the descending rack by the hands of the workman, or it may previously'have been clipped to this rack as heretofore explained. In any event, there is now a sheet of veneer lying on the empty truck, and this sheet may be slid off sidewise without danger of breaking or otherwise injuring it.

Veneers are'not all of equal quality. In manufacturing plywood, even though all of the piles are of the same wood, the outer plies must be of high quality, whereas the inner or core plies may contain imperfections rendering them unsuitable for use as face plies. I therefore place on opposite sides of the track,- at the unloading point, a pair of receiving beds or platforms E and F. As the sheet of veneer, which has just been placed in a horizontal position on the empty truck, lies exposed, a glance will sufllce to show whether it can be used for faces or whether it is fitted only for use in places where it is concealed by other plies. If the former, it is slid over upon the bed or platform E, or, if the latter, it is placed on the platform F. The righthand truck in Fig. 10 now contains only an empty rack. This rack is then swung up into an upright position of rest against the standing stakes. The second rack of the loaded group may now be swung down, bringing into a horizontal position a second sheet of veneer.

This second sheet is then placed on the bed or is then ready to be rolled to the loading point where other sheets of veneer to be dried are inserted between the racks.

It will be seen that when an assembly of racks and veneers stands upright on a truck, air may be blown or drawn through the assembly in vertical directions, either up or down.

In order to dry the veneers in a reasonably short time, it'is not feasible to rely .upon the natural atmospheric air currents to effect the drying. Furthermore, in order to prevent buckling of the veneers,-the grain of the woods should be approximately horizontal instead of vertical. With this disposition of the grain in the wood, the drying air should move past the sheets inthe vertical direction, namely in the direction in which shrinkage of the wood occurs; and, to

- staggered with respect to the partitions.

produce air currents of that type, artificial aids must be provided.

In accordance with my invention, the loaded trucks are rolled into drying chambers or tunnels so designed that when air is blown into one end, it zigzags up and down through the assemblies of veneers and racks as it travels toward and to the opposite end. This drying system is diagrammatically illustrated in Figs. 1 and 2, in which 25 represents a long tunnel-like building, the interior of which is slightly wider than an assembly ofracks to be dried, and the height of which is somewhat greater than the overall height of a truck loaded with the tallest racks; veneers peeled from the same length of log being produced in various lengths measured transversely of the grain so that racks of different heights house the various lengths of sheets. The building 25, to which I shall refer as a kiln, stands over a pit 26 extending throughout the entire length of the same and having a width almost as great as that of the kiln. This pit is conveniently produced by excavating the soil between the longitudinal foundation walls 21, 21 for the kiln, and connecting these foundation walls with a horizontal wall 28 that constitutes the fioor of the pit. Rails forming part of the track system for the trucks are located on the tops of the two foundation walls 21, 21 within the kiln. The pit is divided into a series of compartments by transverse partitions 29 extending across the depth and width of the same at intervals throughout its entire length. These partitions are so spaced that the distance between centers of adjacent partitions is an evenmultiple of the length of one of the trucks. Therefore, when the kiln is filled with trucks engaged with each other end to end, and two of the trucks are placed so as to meet directly over one of the partitions, other trucks will meet each other just above every other partition.

In the top of the kiln are gates 3| extending transversely across the entire width of the kiln and hinged to the kiln so that one long edge of each lies close to the roof of the kiln. The width of each gate, measured in a direction at right angles to the hinge axis, is preferably somewhat greater than the distance between the roof of the kiln and the tops of the shortest racks with which a truck may be loaded. Therefore, when loaded trucks are rolled into the kiln, the gates will engage with the tops of the racks along the lower edges-of the gates, and will ride on the rackassemblies as the trucks move. Thus, regardless of the height of the racks, these gates will always form barriers across the space within the kiln between the roof and the tops of the rack assemblies. Where hinged gates are employed, it is necessary that the trucks always be caused to travel in one direction, since otherwise the gates would be caught in the openings in the top of the rack assemblies and broken. In the arrangement shown, the trucks are intended to enter the kiln at the lefthand end,'as viewed in Fig. 1, and leave at the righthand end.- The spacing between the gates is the same as that between the partitions 29, and the gates are The kiln may have removable end walls or doors 32 and 33. Means are provided to'blow air, prefduit 35 and discharge it into the righthand end of the pit through-an outlet member 36 passing through a wall 31 that closes the righthand end of the pit.

In Fig. 1, the kiln is shown longenough to house thirteen trucks engaged end to end. The I first partition 29 from the right lies in the vertical plane in which the second and third trucks meet, and each subsequent partition lies'three truck lengths to the left of the preceding partition. There are illustrated three gates each of which lies approximately midway between the consecutive partitions. Assuming the conditions to be such as represented in Fig. 1, it will be seen that if air is blown into the righthand end of the pit, it can travel along the pit only until it reaches the first partition 29 and therefore rises through the assemblies in the upper regions of the kiln. Forward movement of the' air into the top of the kiln is checked when the first gate is reached and, therefore, the air now flows down through the rack assemblies lying to the left of the first two and to the right of the gate. When the air emerges below the trucks on which are located the assemblies through which the air has traveled in the downward direction, it enters the pit to the left of the first partition 29 and then can again move along the pit, but only until the second transverse partition is reached. The only outlet for the air is up until it is finally discharged into the 'pit be yond the partition at the extreme left of the series of partitions in the pit.

The trucks may be provided with parallel partitions as indicated at 38 in Figs. 11-13; these partitions extending across the entire width of the space between the side or longitudinal members of the frame l3 and at right angles to these members; the partitions reachingfrom the plane of the lower edge of the frame to the top 'and preferably to the plane of the upper faces.

of the sills l4. Therefore, if the trucks are so positioned in tunnel or kiln that the transverse partitions 29 in the pit do not register with the meeting points between trucks as shown in Fig. 1, the partitions 38 in thetruck will serve as barriers to prevent the drying air from being blown alongthe pit across the tops of the partitions in the pit. Otherwise, if the trucks were shifted to the right or left from the positions which they occupyin Fig. 1, there would be but little circulation of drying air through the groups of veneers as the air would find a more direct passage to the air outlet across the tops of the partitions in'the pit.

It is believed that the functions of the various features of my invention and the manner of operation of these features which are structural have been sufiiciently described in the foregoing part of this specification and therefore require no further description. It will of course be understood that while I have described with great particularity what -I believe to be the best mode of carrying out my invention, including specific embodiments of each structural part,

I do not desire to be limited to such details; but

intend to cover all processes, machines, appa-" ratuses, structures, and devices coming within the definitions of my invention constituting the appended claims.

I claim:

1. The method of drying large sheets of knifecut wood veneer which consists in inserting each sheet in an open-work container having therein a chamber at least as long and as wide as the sheet and a depth somewhat greater than the thickness of the sheet, holding the container upright with the grain of the wood running horizontally, and-causing drying air to flow in the vertical direction past the container in the plane and across both sides thereof.

2. The method of drying large sheets of knifecut wood veneer which consists in inserting each sheet in an open-work container having therein 'a chamber at least as long and as wide as. the

sheet and of a.depth somewhat greater than the thickness of the sheet, placing a series of such filled containers face to face in upright positions, and causing air to flow through the assembly of filled containers parallel to; and in contact with the sheets of veneer.

3. The method of drying large sheets of knifecut wood veneer which consists in inserting each sheet in an open-work container having therein a chamber at least as long andas wide as the sheet and of a depth somewhat greater than the thickness of the sheet, placing a series of such filled containers face to face in upright positions with the grain of the wood extending horizontally, and causing air to flow vertically through the assembly of filled containers parallel to and in contact with the sheets of veneer.

4. The method of drying large sheets of knifecut wood veneer which consists in'inserting each sheet in an open-work container having therein a chamber that is at least as long and as wide numbers of filled containers face to face on carrier means, moving the carrier means into a drying chamber, and causing air to flow through the assembled containers in the planes and past all of the containers. v

5. The method of drying large sheets of knifecut wood veneer which consists in lightly holding a considerable number of such sheets near each other in upright positions with the wood grain extending horizontally in such a manner that each sheet while in a fiat state is not subj'ected to any gripping forces suflicient to prevent freedom of movement in contracting, while drying, and without covering any considerable surface area of any sheet, and causing currents of gaseous drying material to flow vertically across both faces of each sheet.

6. The method of drying large sheets of knifecut wood veneer which consists in lightly holding wood veneer which consists in causing each sheet to stand on edge with the grain running hori- "zontally, lightly constrainingeach sheet so as.

to compel it to remain in an upright position and of gravity at the proper rate'to compensate'for the natural contraction of the wood'indrying,

and causing currents Ofdrying gases to .,flow

in the vertical direction past both broad faces of each sheet. a

. GEORGE R. MEYERCORD.

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