US2757920A - Veneer dryer - Google Patents

Description

Aug. 7, 1956 E. P. MORRIS VENEER DRYER Filed June 14, 1952 .'5 Sheets-Sheet 1 u IH I, l n.

IN V EN TOR. fawn/ao H Ma/ws Afro/iw ys Aug- 7, 1956 E. P. MORRIS 2,757,920

VENEER DRYER Filed June 14, 1952. 5 Sheefs-Sheet 2 |H VIII" /I IL IN VEN TOR. Eon/m0 PMae/s E. P. MORRIS Aug. 7,'1956 VENEER DRYER 5 Sheets-Sheet 5 Filed June. 14, 1952 i l IN V EN TOR.

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United States Patent O VENEER DRYER Edward P. Morris, Painesville Township, Ohio, assignor to The Coe Manufacturing Company, Painesvlle, Ohio, a corporation of Ohio Application .lune `1.4, 1952, Serial No. 293,545

2 Claims. (Cl. 263-28) The present invention relates to Aapparatus for drying veneer and the like by the circulation of heated air thereabout.

The principal object of lthe invention is the provision of a new and improved dryer for use in the manufacture of veneer or other like material and which is arranged to flow heated air about decks of conveyors carrying the material to be dried, the air being recirculated about the material and heated directly by a fuel burner located in the stream of the circulating air and providing the sole source of drying heat. i'

Another object of the invention is ,the provision of a new and improved veneer ,dryer of the character referred to comprising a housing having decks of conveyors therein for passing sheets of material, such as veneer, therethrough, means being provided for withdrawing yair from the interior at one portion of the housing, heating the withdrawn air directly by a fuel burning device and vreturning the heated air to' another portion .of the interior of the housing in such a manner that the hea-ted air Vis distributed about the decks of conveyors to cause the material thereon to be dried evenly.

Another object lof the invention is the provision of a veneer'dryer of the character referred to having means to control the fuel burning device so that the temperature of the air circulated over the veneer is within the most etlicient limits and below the temperature which might damage the veneer.

A further object of the invention is the provision of a new and improved veneer dryerof the character referred to including means to selectively divert the products of combustion from the burner to the exterior of the housing to prevent the entrance of soot and the like into the housing during periods at which inei'licient combustion may occur.

The invention resides in certain constructions and cornbinations and arrangements of parts and further objects and advantages will be apparent t o those skilled in the art to which'it relates from the following description of preferred'embodiments described with reference to the accompanying drawings forming a part of this specification and in which Fig. l is a fragmentary side elevational View of a veneer dryer embodying the invention and utilizing gas fuel;

Fig. 2 is a plan View of the dryer shown in Fig. l.;

Fig. 3 is asectional view taken along line 'Qa-3 of Fig. 2;

Fig. 4 is a sectional view taken along line 4 4 of Fig. 2; l

Fig. 5 is a fragmentary elevational view of a veneer dryer embodying another form of the invention and utilizing fuel oil, and

Fig. 6 is a plan View of the dryer shown in Fig. 5.

Referring to Figs. 1 to 4, the veneer dryer shown is adapted to burn gas to directly heat air subsequently circulated about the veneer or other material to be dried. The dryer comprises a housing structure 10 which may 2,757,920 Patented Aug. 7, '195.6

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be of any suitable `construction such as a metal framework having a sheet metal top wall 11 and side walls 12, 13, each comprising a series .of doors 14 hinged to `the framework so that they may be 4opened for access to the interior of the housing. Preferably -the doors and top .wall are suitably insulated to minimize heat transfer therethrough.

The material to be dried vis conveyed through the dryer housing 10 by a power-driven multi-deck conveyor mechauism 15 which ,extends through the housing and projects frorn `opposite ends. The multiple deck ,conveyor may be of any suitable construction and includes a framework having a plurality of decks 16 each comprising a series of rollers arranged in a horizontal plane 'and driven by sprockets and chains to move material thereon from one end Vto the other, in a manner well understood in the art. In the apparatus shown, wet sheets of veneer or any other sheet type material which is desired to be dried, 4is placed upon the respective conveyor decks 1 6 and are moved thereby through the housing 10 at a suitable rate to effect drying thereof inside the housing.

Heated air is circulated through the housing 10 and about the veneer sheets on the conveyor decks 16. In the present embodiment air is withdrawn from vthe interior of the housing through two exhaust manifolds 18, 1 9 Vthe inlets of which ,open into opposite sides of the housing, respectively, lpreferably adjacent to the end at which the lveneer is fed into the housing. The manifolds 18, 19 discharge into the intakes of centrifugal type fans 20, 2 1, respectively, which are vdriven by electric motors 22, ,2.3 through belt drives 24, 25, respectively. The fans 20, 2 1 discharge into ythe liared end of duct -26 which is supported on the top wall 11 of the housing and which may be formed of sheet metal attached to a suitable supporting frame, the details of which are not shown since such type of construction is well known in the art.

Preferably, an exhaust stack 27 is provided at the throat of the duct and an adjustable damper 2S is associated with the stack to deflect air upwardly from the duct and into the atmosphere. The damper is operated to d ecct `more or less air through the stack by a suitable motor and .limit switch 2,9-

A sas burner manifold 30 extends transversely of the v.Central portion of the duct v26 and is supplied with gas fuel through a pipe 3 1 connected with a suitable source of `gas supply. Air for supporting combustion of the gas is fed to the burner through a pipe 33 and is forced through the pipe by an electric motor driven blower ,34. Preferably, a zero regulator in the gas line controls the amount of air supplied to the burner. The burner discharges its ame toward the right hand end of the duct, and na suitable ame rectifier 35 is provided to initiate combustion at the burner. The right hand end of the duct 26 opens into a cross duct 3 8 which extends across the top of the housing 10 and has inlet manifolds 3 9, 4l) connected at opposite ends thereof which extend downwardly along the outsides of the housing and which direct air into the nsides of the housing and between the decks.

16 of the conveyor 1 5.

The duct 38 has a series cf horizontally eirtendingad-f instable 10m/.er type dempers 42 ,at the. Outer ends thereof which serve to control the quantity and direction of air entering the respective manifolds 39, 40. The outer walls l of the manifolds are curved downwardly at `the top portions thereof, as shown, and the lower portions slope inwardly so that the air directed thereagainst by the dampers impinges on the sloping wall and is deflected into the housing through openings 43 in the sides thereof. Thus, the distribution of Aair* between the .decks 1 6 of the convsyor san be determined to a. certain extent by the angular Position 0f the dempers 42 which can be adjusted by a lever 44 having a link 45 attached thereto which is oon- 'number of air heating and circulating systems may be employed in dryers embodying the invention, and the number used is a matter of design, taking into consideration the length of the dryer.

` It will be seen that air withdrawn from the interior of lthe housing through the manifolds 18, 19 is conducted intodirect contact wth the gas flamesat the burner 30 -and is heated thereby and this air and the gases of combustion are reeirculated through the housing contra to the direction of movement of the veneer ou the conveyor and returned to the burner through the manifolds 39, 40. The heated air picks up moisture as it passes toward the manifolds 18, 19, and a portion of the moisture laden air is exhausted through the stack 26 before it is returned to contact with the flames at burner 30.

The amount of fuel burned and consequently the heat .input into the drying air is controlled by a thermostat 47 having its thermal responsive element subjected to the air inside the cabinet 10 and is operative to cause sufficient fuel consumption to be maintained to properly dry the material in the cabinet. The control of the burner by thermostat 47 is modified by a temperature limit thermostat 48 located in the duct 26 adjacent to the cross duct -38`and having its thermal responsive element subjected to the heated air passing to the manifolds 39, 40. This control is operative to prevent excessive heating of the air which might damage the material passing through the dryer on the conveyor decks. The burner controls referred to are conventional and the details thereof are not fully shown or described.

In the dryer shown in Figs. 4 and 5, the air is heated by an oil burner, and comprises a housing 60, which may be of similar construction to housing 10, and a multiple deck conveyor 61, similar to conveyor 15, extending therethrough and adapted to movesheets of veneer 'or the like from the left hand end thereof toward the right as viewed in the drawings, and in a manner similar to that described with reference to the first'form of dryer. Air is withdrawn from the interior of the housing 60 through manifolds 62, 63 which open into the sides of the housing 'adjacent to the left hand end thereof and direct air from the interior ofthe housing into a ceramic lined cylindrical combustion chamber 64. The chamber 64 has a. tubular ceramic member' 65 concentrically arranged therein and an oil burner nozzle 66 extending into the left hand end thereof and projecting into one `end of the tubular member. The'no'zzle 66 is connected with an electric motor driven blower 68 through a pipe 69, and the blower feeds a mixture of oil and air to the nozzle so that the fuel is burned in the tubular member 65. The oil burner may be of conventional design and may be ignited by any suitable device, such as an electricV pilot, not shown.

The chamber 64 is connected with the larger end of a tapering duct 70 the opposite end of which is connected to the intake of two blowers 71, 72. The blowers comprise centrifugal fans which are attached to a shaft 73 driven by an electric motor 74 through a belt drive 75. The exhaust of the blowers 71, 72 discharge into a cross vduct 76 which extends across the top of the housing 60 and discharges into vertically extending manifolds 78, 79 which are similar in form to the manifolds 39, 40 described hereinbefore. These manifolds have louver type dampers 80 therein which are similar to the dampers 42 and function in a similar manner to control the flow of heated air and gases into the manifolds and they can be )i closed to block the passage of gases into the manifolds for a purpose described presently.

When the oil burner is initially operated and until the cylinder 65 and other associated parts of the burner become heated considerable soot, etc. is given off. The soot containing air and gases is purged from the housing through a stack 82 located at the top duct 76 and having a plurality of dampers 83 in the bottom thereof. By closing the dampers and opening dampers 83, the objectional products of combustion are passed to the atmosphere rather than into the housing 60 until more complete cornbustion is achieved, at which time the dampers 83 are closed and dampers 80 are opened.

Moisture laden air is vented from the system through a stack 85 which is connected with the manifolds 62, 63 by pipes 86, 87 and the air is withdrawn from the manifolds by a blower 88 having its intake connected with the pipe 86 with which the pipe 87 is connected. The amount of venting is regulated by varying the intake opening of the blower 88.

It will be seen that air is drawn from the left hand end of the housing and directed through and around the tubular member 65 which is heated by the flame from the nozzle 66 and the heated air with the hot gases of combustion are then moved by the blowers 71, 72 into the cross duct 76 and into the housing where they are distributed over the decks of the conveyor 61 and passes to the left hand end of the housing and up through the manifolds 62, 63 to be reheated.

The dryer 60 has two air recirculating and heating systems connected therewith and part of the second system may be seen in the drawings. Like parts of the second system bear the same reference characters as those of the system described and have a prime affixed thereto.

It will be seen that by my invention there has been provided a veneer drying apparatus which heats the drying air by direct contact with a fuel burning device located on the top of the dryer cabinet and that the total heat for evaporating the moisture in the material to be dried is furnished by the burner, thereby providing a relatively compact, self-contained drying apparatus which is highly efficient and which can be closely regulated to provide the degree of drying desired. While only two forms of the invention have been described it is my intention to cover hereby all modifications, adaptations and alternate forms of construction falling within the scope of the appended claims.V Y v Having thus described my invention, I claim:

l. A dryer for veneer and the like comprising an elongated housing having top,.bottom and side walls, a pluralityrof tiered vconveyor decks extending longitudinally of said housing and adapted to convey sheets of veneer andthe like through said housing, power means to actuate said conveyor decks, means forming an air duet extendingy over the top wall of said housing and longitudinally thereof, vertical manifolds on opposite sides of said housing communicating with one end of said duct each in communication with an opening in opposite side walls of said housing respectively and forming an air intake from said housing, two vertical manifolds adjacent to and in communication with the opposite end of said duct and each in communication with .an opening in opposite side walls of said housing respectively and forming an air discharge from said duct into said housing, said openings extending substantially the height of said side walls, baille means in the last named two manifolds for directing air angularly into said manifolds against one side thereof to distribute the flow of air from said manifolds substantially uniformly over conveyor decks opposite the last mentioned openings in said side walls of said housing, fan means associated with said duct to circulate air longitudinally through said housing and said duct, fuelburningnmeans in-saidrduct and adapted to produce la flame in s aid ductfor heating air passing therethrough, the products of combustion of said fuel burning means being ntermingled with the air passing through said duct into said housing, and `a flue connected with said duct intermediate said fuel burning means and the intake of said duct from said housing whereby air passing through said duct may be discharged to the atmosphere.

2. A dryer for veneer and the like comprising an elongated housing having top, bottom 'and side walls, a plurality of tiered conveyor decks extending longitudinally of said housing and adapted to convey sheets of veneer and the like through said housing, power means for actuating said decks, means forming an air duct extending over the top wall of said housing and longitudinally thereof, vertical manifolds communicating with one end of said duct each in communication with an opening in opposite side walls of said housing, said manifolds having two spaced side walls substantially vertical to the side walls of said housing joined by a third wall dening an acute angle with the side wall of the housing, said manifolds and said openings forming yan air discharge from said duct into said housing, damper means in said manifolds for directing air angularly into the manifolds against said third wall to distribute the ow of air from said manifolds substantially uniformly over conveyor decks opposite said openings, two vertical manifolds adjacent and in communication with the opposite end of said duct each in communication with an opening in opposite side Walls of said housing, respectively, and forming an air intake from said housing, fan means in said duct to circulate air from said duct longitudinally through s-aid housing and return to said duct, fuel burning means in said duct and adapted to produce a llame in said duct for heating air passing therethrough, the products of combustion being intermingled with the air passing through said duct into said housing, and vent means in said duct intermediate said air intake from said housing and said burner including power actuated fan means having its inlet connected to said duct and its outlet connected to atmosphere.

References Cited in the le of this patent UNITED STATES PATENTS Re. 17,594 Vance Feb. l1, 1930 1,138,086 Coe May 4, 1915 1,675,284 Vance .Tune 26, 1928 1,704,280 Burton Mar. 5, 1929 1,787,063 Cano Dec. 30, 1930 1,914,567 Hopkins et |al. .Tune 20, 1933 2,297,979 Peck Oct. 6, 1942 2,370,422 Reed Feb. 27, 1945 2,370,886 Solberg Mar. 6, 1945 2,658,742 Suter et al. NOV. 19, 1953

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