US2553452A - Drying kiln - Google Patents

Description

May 15, 1951 c. R. GUTHRIE DRYING KILN '2 Sheets-Sheet 1 Filed March 3l, 1948 May 15, 1951 c. R. GUTHRIEy 2,553,452

DRYING KILN Filed March 5l. 1948 A 2 Sheets-Sheet 2 Patented May 15, 1951 UNITED STATES PATENT OFFICE 3 Claims.

The invention relates to drying kilns and an l object of the invention is to provide a kiln comprising a specially designed building consisting of a steel frame and enclosed by insulated aluminum panels and doors arranged in such a manner that they do not obstruct or interfere with the predetermined currents of air created in said kiln building.

Another object of the invention is to provide a kiln of the character indicated above, the building of which contains the necessary apparatus for heating the air in said building comprising a fan or a blower to set the air into motion to flow through prearranged ducts and air Ways while being directed by baffles.

A further object of my invention is to provide a kiln of the character indicated above, in which inlet dampers are automatically opened to permit a predetermined amount of fresh air to enter, when the used drying air contains a predetermined amount of moisture.

A still further object of the invention is to provide a kiln of the character indicated above, which is equipped with outlet dampers discharging any superuous amount of air from the kiln.

Another object of my invention is to provide a kiln of the character indicated, in which the mixture of fresh air and pre-used drying air is forced through a humidifying chamber, where a controlled amount of humidity may be added to said air mixture before it starts again its circuit through the kiln.

Other objects of the invention may appear in the following specication describing it with reference to the accompanying drawing illustrating a preferred embodiment of the invention. It is, however, to be understood that the inven tion is not to be limited or restricted to the exact construction and combination of parts described in the specification and shown in the drawing, but that such changes and modifications may be made, which fall within the scope of the claims appended hereto.

In order that the invention may be better understood I will now proceed to describe it with reference to the accompanying drawing, in the several iigures of which similar parts are indicated by similar reference characters and in which:

Figure l is a diagrammatical View showing a longitudinal section through the kiln according to the invention.

Figure 2 is a sectional view taken on line 2--2 in Figure 1 Figure 3 is a sectional view taken on line 3-3 in. Figure 1.

Figure 4 is an elevational outside view of a Wall of the drying kiln according to the invention, and

Figure 5 is a sectional view in a larger scale and taken on line 5--5 in Figure 4.

The drying kiln embodied herein comprises a building B of preferably elongated rectangular shape, on the floor IB of which a plurality of comparatively long spacers lI are arranged parallel to each other and longitudinally of the building B. The spacers are spaced from each other at such a distance that each pair of adjacent pair parallel spacers is adapted to support a plurality of boards I2 or the like extending transversely of the building and parallel to each other and spaced apart from each other as shown at I 3. On top of these boards some more spacers II are placed longitudinally of the building and parallel to and spaced apart from eac/h other, and another tier of boards I2 or the like is arranged on top of each pair of the spacers resting on the first described tier of boards. The boards in the second tier extend also transversely of the building and parallel to each other and are spaced from each other as shown. The stacks I5 of boards are arranged so that one end of one stack is located as a comparatively short distance from the end wall Ill of the building, that a space I5 is left between adjoining stacks and that there is also a space between the stacks and each of the longitudinal walls I6 of the building B. A partition I'I extends transversely across the building and divides it into a drier room I3 and a heater room I9. There is left a space 2B between the partition Il' and the adjacent stack of boards.

In the heater room I9 an air heating device 2I of any preferred conventional kind and construction is arranged, which may heat air passing therethrough either by means of oil, coal, high pressure steam coil or the like. A fan 22 sucks the heated air out of the heater and blows it through a supply duct 23, which extends upwardly through the ceiling 24 of the building B and horizontally and longitudinally in the attic 25 between the ceiling and the roof 25. On the inner end portion of the supply duct a pair of branch ducts Z'la are arranged, which extend downwardly through the ceiling 24 into the drier room I8 approximately centrally between the end wall I4 and the partition I'l. On the end portion of each branch duct two high velocity registers or air nozzles 2lb are mounted at a level above the top tier of the boards I2. The nozzles are arranged so that they expel heated air toward the end Wall I4 and the partition I1 and the expelling force is such that the expelled air hits the wall and the partition without coming into direct contact with the stacked lumber. The heated air is then deflected toward the iioor Ii), thus building up a pressure. To prevent the heated air from flowing around the stacks S narrow vertical baiiles 28 are arranged on the longitudinal side Walls I6, so that they project inwardly therefrom and abut the outer corner portions of the stacked boards. Between the boards located adjacent the space l a baille plate 2g is arranged adjacent each side wall l and closing the ends of the 'space I5. The heated air, which is expelledthrough the nozzles 2lb flows therefore through the spaces formed by the spacers ll between the stacked g boards toward the center as indicated by the arrow heads in Figure 1.

In the central space l5 a portion of the heated air flows upwardly, where it combines with the air being expelled from the nozzles 2l. The biggest portion of the air in the space E5 is sucked by the force of the fan 22 through an opening 3U in the oor 0 into a return duct 3| arranged underneath the oor. This return duct is connected with a mixing chamber 32 located in the heater room I9. An air inlet 33 extending through the roof 26 is normally closed at its bottom end by dampers 34 preventing fresh air from entering the mixing chamber. When, the return air has absorbed enough moisture from the lumber Vbeing dried to contain a predetermined amount of moisture, the dampers are opened by any conventional means, such as an electro-magnet for instance, controlled by a conventional hygrostat 35 or the like. The entering fresh air mixes with a portion of the air flowing through the return duct. The air in the mixing chamber is sucked by the fan 22 through a duct 3E into a humidifying f chamber 31. Here the mixed air is further humidied to a predetermined degree, if required, by conventional hygrostat control means (not shown). From there the air is drawn into and The superfluous portion of the return air through the heater 2i for another cycle. L

passes the entrance to the mixing chamber 32 and keeps on flowing through the return duct '31, which extends beyond the end wall 38 of the heater room I9 and Yprojects then upwardly and outwardly as indicated at 39 and d!) respectively. The end opening of the return duct portion 40 may be closed by outlet damper 4|. A drain pipe 42 is connected with the return duct 3l and leads to a pit 43 so that any condensed water col Y lecting in said return duct ows off through said drain pipe.

To make the above described drying kiln highly effective, it is necessary to build up a certain amount of pressure, so that the heat will pene-gA trate the lumber better to open the pores and to start the sap to flow more freely.l To attain this object the building B is constructed as 'follows:

A frame F' consists of a plurality of verticalA low rbodies from two sheets 45 of aluminum, which are connected with each other by end and side walls, lconsisting each of a strip of aluminum. The hollow in each of these bodies is lled with 4 any preferred heat insulating material 41. The panels are secured to the vertical frame members by carriage bolts 48 slipped into the slot 45 and extending through said slots and between two adjacent panels P held against the inside or slotted face of the frame member. An elongated plate 49 of aluminum is provided with a plurality of equidistantly spaced holes 50 permitting the bolts 48 to extend therethrough. Nuts 5I on said bolts force the plates 49 clampingly against the panels P and hold them in position. Any open spaces in the walls constructed, as described above, are lled with any preferred conventional mastic. The walls may be reinforced by cross frame members 52 extending transversely between the vertical frame members 44.

-The above description shows clearly that a kiln building of the character described eliminates all obstructions adapted to cause any deflection of the air currents, since all the panels are secured on the inside of the frame members.

I claim: y

1. A lumber drying kiln, comprisingan elongated building including end and side walls, a floor and a roof, a transverse partition dividing the interior of the building into a drying room and a smaller heater room, a ceiling extending above the two rooms to provide an attic between the same and the roof, a heater within said heater room, an air mixing chamber within said heater room and communicating with said heater, an air inlet depending through the roof and said ceiling and communicating with said mixing chamber, a main duct extending from said heater through said ceiling and the attic to a point above the approximate center of said drying room, a branch duct extending transversely from the free end of said main duct, nozzles extending from the opposite sides of said branch duct, a suction fan mounted within said heater adjacent the inlet end of said main duct for forcing the heated air through the latter to said nozzles, said nozzles being adapted to discharge the heated air laterally therefrom toward the opposite ends of said drying room for its circulation over and back through lumber arranged in spaced tiers within the latter,` an air return duct extending beneath the floor and opening therethrough at the approximate center of said drying room, and a second branch duct extending upwardly through the floor into said heater room from said -return duct and communicating with said mixing chamber.

2. The invention as dened in claim l, with .the saidreturn duct having its outlet end extending beyond the second branch duct and the 'outer end wall of said heater room, said outer opening to atmosphere by way of an upwardly and outwardly angled extension thereof, damper means mounted within said extension, and a drain leading from said return duct at the lower end of said extension.

3. The invention as dened in claim 1, with Va 'humidifying chamber interposed between said air mixing chamber and said heater, damper means mounted within said air inletV adjacent its point of connection with said air mixing chamber, and a hygrostaticcontrol means within said mixing chamber for regulating the admission of fresh air thereto.

CLIFFORD R.

- (References on following page) REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 638,831 Barbour Dec. 12, 1899 895,620 Dejonge Aug. 11, 1908 1,330,238 Carrier Feb. 10, 1920 Number Number Name Date Carrier Oct. 11, 1921 Hirt Oct. 17, 1922 Cobb Oct. 14, 1930 Polderman May 4, 1937 FOREIGN PATENTS Country Date France July 8,' 1922

Images