US3477139A

US3477139A - Drying chamber for drying lumber

Info

Publication number: US3477139A
Application number: US688776A
Authority: US
Inventors: Robert Hildebrand
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-12-07
Filing date: 1967-12-07
Publication date: 1969-11-11
Anticipated expiration: 1986-11-11

Description

NOV. 11, 19.69 R, HlLDBRND 3,477,139

DRYING CHAMBER FOR -DRYING LUMBER Filed Dec. '7, 1967 United States Patent 3,477,139 DRYING CHAMBER FOR DRYIN G LUMBER Robert Hildebrand, Nurtinger Strasse 68, Oberboihingen,

Wurttemberg, Germany Filed Dec. 7, 1967, Ser. No. 688,776 Int. Cl. F2611 3/ 04, 25/06 U.'s. c1. 34-191 p s Claims ABSTRACT OF TH DISCLOSURE means are provided to regulate the condition of the drying medium. The fan is mounted in the loft so that it may be reversed in position to face in either one direction or a direction 180 opposed thereto so that by pivoting the fan between is two positions, the direction of circulation through the drying room may be reversed.

`The present invention relates to drying chambers, and has particular application to a chamber for drying lumber wherein fan means is provided for circulating the drying medium, preferably air, in a given direction through the lumber.

For drying lumber and other materials, it is advantageous to reverse the direction of air flow from time to time in order to obtain uniform drying throughout the drying chamber. Prior to the present invention, this has been accomplished by the use of a stationary fan Whose direction of rotation may be reversed when it is desired to reverse the direction of the ilow. Such reversible fans have srnall efficiency because they must be designed to forward the drying medium in one direction when rotated in a first direction, and in the opposite direction when rotated in the opposite direction.

The present invention enables the use of a high-eiiiciency fan or blower which is designed to forward air in only one direction and a reversal of ilow is obtained pivoting the entire fan about an axis, preferably about an axis disposed substantially at right angles to the axis of rotation of the fan. The fan is held in one position for predetermined period, for example several hours, and then is rotated 180 and held in the opposite position for a similar period so that the two periods, the direction of flow is reversed without reversing the direction of rotation of the blades. The present invention therefore makes it possible to use fans of simple design .having a high efficiency.

In accordance with another feature of the invention, the fan is an axial fan mounted in a ring which surrounds the fan blades and is provided with oppositely disposed trunnions or pivot pins mounted in bearings to support the fan, one of the pivot pins having a drive wheel secured thereto. The bearings for the fan support may be of simple design to permit pivoting of the fan, or retention of the fan in its adjusted position, by means of the drive wheel, which is connected, at least indirectly, with a positioning motor.

To avoid the necessity for a positioning motor, the pivotal axis for the fan may be offset from the rotary axis of the fan blades so that the reaction force produced by the rotation of the fan provides a pivoting force for pivoting the fan on its trunnions. A stop is provided to halt the pivotal movement of the fan in the desired position so that by operation of the stop, the position of the fan may be changed as desired.

31,477,139 Patented Nov. 1l, 1969 All of the objects of the invention are more fully set forth hereinafter with reference to the attached drawing wherein:

FIG. 1 is a transverse sectional view of a drying chamber embodying the present invention;

FIG. 2 is a longitudinal section taken along the line 2-2 of FIG. l;

FIG. 3 is an enlarged sectional view taken on the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 3; and

FIG. 5 is a view similar to FIG. 4 showing a modified embodiment of the present invention.

In the embodiment of the invention illustrated in FIGS. 1-4 inclusive, the drying chamber 1, includes side walls 22, end walls 23 having doors 24 therein through which the lumber 7 is transported, and a roof 25. The lumber 7 is stacked on the floor of the drying chamber, for example on pallets 26 by means of conventional vehicles.

In accordance with the invention, the drying chamber is provided with means for circulating drying medium through the lumber from one side thereof to the other for a predetermined period and thereafter for circulating the dying medium in the reverse direction through the lumber. To this end, the drying chamber is provided with a ceiling 2 spaced downwardly from the roof to divide the chamber into a drying room 31 and a loft 32 through which the drying medium is circulated. Along the opposite sides, the ceiling is spaced from the side walls 22 to provide flow-through openings 3 and 4, the opening 3 of which is covered by a heat register S, in the present instance a heat exchanger of conventional design. 'Ihe air is circulated from one wall to the opposite wall within the drying room 31 and is returned through the loft 32. In order to reduce the moisture content of the drying medium, means is provided at 26 to control the moisture content of the circulating drying medium. In its simplest form, the moisture-controlling means may consist of dampers operable to exhaust moisture-laden air to the atmosphere and to introduce fresh dry air.

In the loft, the drying medium, in the present instance air7 is circulated by a series of fans 46, each of which is mounted in an upright partition 13 extending longitudinally of the loft 32 of the drying chamber 1. Each fan is mounted so it can pivot about an axis transverse to the axis of rotation of its blades so that it may face in opposite directions. When facing as shown in FIG. 2, the air circulation is as indicated by the arrows therein. WhenV the fan reverses to face the opposite direction, the air circulation is opposite to that indicated by the arrows.

In accordance with the invention, to permit ready reversal of the flow, each fan 6 is mounted in a fan support ring 8 surrounding the fan blades 10 and having spider struts 17 for mounting the drive motor 9 for the fan. At diametrically opposite sides, the ring `8 is journalled in the partition 13 by means of trunnions or pivot pins 11 and 12. The ring is mounted in an opening 30 in the partition 13 Which corresponds in outline -to the fan support ring 8. The upper trunnion 11 has a drive wheel 14 mounted within the opening 30 and projecting therefrom, as shown in FIG.. 3 to mesh with a drive pinion 15 carried by the drive shaft of a positioning motor 16 mounted on the partition 13. When the motor is energized, it drives the Wheel 14 to rotate the ring 8 in the opening 30 to thereby control the direction in which the fan faces. When the motor 16 is de-energized, it serves to retain the fan in its adjusted position.

As shown in FIG. 2, a plurality of fans are provided in the partition 13. Although each fan may be provided With a separate positioning motor, it is more advantageous to gang the fans together, for example by means of a drive chain 27 and sprockets 28 on the individual fan support rings as shown in FIGS. 2-4. In this way, only a single position motor iS required. In the embodiment of the invention illustrated in FIGS. 1-4 inclusive, the positioning motor is shown as a conventional rotary motor, but it should be understood that the positioning motor may consist instead of a hydraulic or pneumatic operating cylinder connected to the fan ring 8 in any convenient manner. Alternatively, the motor may be omitted and a simple mechanical manual control may be provided for pivoting the fans and locking them in position.

It may be desired to use the reaction force of the fan to supply the turning force for pivoting the fan between its oppositely facing positions, For example, as Shown in FIG. 5, the fan 6 is mounted in a fan support ring 8 having upper and lower trunnions 11 and 12 respeclively, whose common axis is disposed offset from the rotary axis of the fan blades 10. The trunnions 11 and 12' mount the fan 6 in an elliptical opening 30' in a partirion 13 corresponding to the partition 13 of the previously described embodiment. In order to ll the opening 30', the fan support ring includes a crescent-shaped appendage 18 so that it presents a symmetrical outline relative to the' axis of the trunnions 11' and 12. Thus, the fan support ring fills the opening 30' in both of its positions which are 180 apart.

Because of the offset relationship of the trunnion axis to the rotary axis of the fan 6, the reaction force of the fan tends to rotate the fan assembly on the trunnions 11' and 12. To secure the fan in either of its oppositelyfacing positions, a stop element 20 projects into the path of the fan ring 8 to form a stop, arresting pivotal movernent of the assembly on the trunnions. In the present instance, the stop element 20 is made as the armature of a solenoid 19 such that when the solenoid 19 is energized, the stop is withdrawn out of the path of the fan ring 8 permitting the reaction force of the fan to pivot the assembly on the trunnions 11' and 12. Upon def-energization of the solenoid 19, the stop element 20 projects into the path of the fan ring 8 to prevent further rotation beyond the 180 pivotal movement afforded by the withdrawal of the stop element from the opening 30'. In this manner, the separate positioning motor is not required, enabling the use of the reaction force of the fan to provide the pivotal movement, under the control of the stop element 20.

In the drying of lumber in a drying chamber in accordance with the present invention, the direction of circulation of the drying medium is reversed only at great intervals of time, for example after several hours. The actuation of the positioning motors, or the Solenoid may be performed automatically by a suitable timer, or may be performed manually by the operator.

While particular embodiments of the present invention have been herein illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a drying chamber having walls, a roof, a ceiling spaced from said roof to separate said drying chamber into a drying room and a loft, and a fan to circulate drying medium through said drying room in a given direction, and means to control the condition of said drying medium in said loft; the improvement wherein said means to circulate the drying medium comprises at least one axial fan mounted in said loft, said fan having blades mounted for rotation about an axis of revolution, a support ring surrounding the blades of Said fan and supporting the fan motor, trunnions transverse to and offset from the axis of revolution of said fan and disposed on a common vertical axis to support said ring for pivotal movement between opposite positions facing respectively in opposite directions whereby in one position Said fan effects circulation through said drying chamber in a given direction, and in the opposite position said fan effects circulation of the drying medium through said drying room in the opposite direction, whereby, upon rotation of said fan, the reaction forces of said fan tend to pivot said fan ring on said trunnions, and means to retain the fan in position comprising a stop element operable between operative and inoperative positions, in the inoperative position permitting pivotal movement of said fan ring by said reaction force's, and in the operative position projecting into the path of the fan ring to prevent pivotal movement thereof by said reaction forces and to hold said fan in one of said opposite positions.

2. A drying chamber according to claim 1 wherein said stop constitutes the armature of a solenoid operable when energized to dispose said stop in its inoperative position and operable when de-energized to dispose said stop in its operative position.

3. A drying chamber according to claim 1 wherein said loft is provided with an upstanding partition spanning between said roof and said ceiling, said partition having an opening for said fan ring, said trunnions pivotally mounting Said fan ring for pivotal movement in said opening, said fan ring having an outline symmetrical to the vertical axis of said trunnions, and said opening conforming in outline to the outline of said fan support ring.

4. A drying chamber according to claim 3 wherein said opening is elliptical and said fan support ring comprises a circular portion surrounding the fan blades and a crescent-shaped appendage to conform said ring to the elliptical outline of said opening.

5. A drying chamber according to claim 4 wherein the center of said circular portion is offset from the vertical axis of said trunnions.

References Cited UNITED STATES PATENTS 1,713,648 5/1929 Feinberg et al. 98--29 1,968,874 s/1934 Cobb 34-191 3,149,932 9/1964 Bachrich 's4-191 FOREIGN PATENTS 521,005 3/1931 Germany. 260,605 10/1928 Italy.

FREDERICK L. MATTESON, JR., Primary Examiner H. B. MMEY, Assistant Examiner U.S. Cl. X.R. 34-223