US2330545A - Desiccating apparatus - Google Patents

Description

Sept. 28, 1943. E. LE B. BENOIT DESICCATING APPARATUS 2 Sheets-Sheet 1l Filed June 10, 1939 Sept. 1943;' Y I 'E-"Bf :sl-:Nokl'r 2,330,545

DESICCATING APPARATUS Filed June 10, 1939 v2 Shee'r.s-Sheec 2 /IN VEN TOR.

Ea'uar'd LeB. BenoitL BY e a MluR/VEYS. 1

Patented Sept. 28, 1943 UNITED STAT-ES PATENT OFFICE DESICCATING APPARATUS Edouard Le B. Benoit, Brooklyn, N. Y.

Application June 10, 1939, Serial No..278,431

' 6 Claims.

The present invention relates to treatment of material with a gaseous medium, and has special reference to apparatus for desiccating freshly.

The several features of the invention, whereby the above-mentioned and other objects may be attained, will be readily understood from the following description and accompanying drawings,

in which:

Figure 1 is a vertical sectional view, partly in elevation, of my improved apparatus in its preferred form;

Fig. 2 is a plan View of the apparatus;

Fig. 3 is a sectional plan view taken substantially on theline 3-3 of Fig. 1; and

Fig. .4, is a sectional view taken on the line 4-4 of Fig. 1.

The apparatus illustrated in the drawings is provided with a treating chamber 2,.a magazine 4 for receiving the material to be treated, and a receptacle or collector 6 for receiving the material after it has been treated. These parts may be made of sheet metal and if desired may be suitably heat-insulated.

The lower endy of the chamber 2 is provided with a cylindrical wall 8 and a bottom wall l0. A cylindrical baffle I2 is secured on the bottom wall concentrically with the wall 8 so as to provide an annular space about the baffle. Leading tangentially into this annular space is a nozzle I4 on the end of a pipe I6. .The gaseous treating medium may be supplied to the apparatus through this pipe and nozzle.

side of a cylindrical chamber 24 which, through a pipe 26, is in communication with the suction end of a fan 28. A pipe leads from the outlet opening of the fan, and communication may be established between this pipe and gas inlet pipe I6 through a branch pipe 32 which is controlled by a damper 34.

`The magazine 4 is adapted to discharge into the treating chamber 2 through an opening 36 in the side of the upper portion of the treating chamber. This opening is adapted to be opened and closed by a quadrant damper 38 in the lower y end of the magazine 4.

The magazine 4 extends a distance above the treating chamber and its vupper end is adapted to be opened and closed by a quadrant damper 40. A pipe 42 leads from the upper end of the treating chamber into the upper end of the magazine 4 and is provided with a damper 44.

The collector 6 is in -communicationwith the treating chamber through an opening'46 which is diametrically opposite the opening 36 leading from the magazine 4. This opening 46 is adapted to b e opened and closed by means of a door or damper 48 mounted in the collector 6. The co1- lector extends downwardly and outwardly from the opening 46 and its lower end is provided with a discharge opening which is adapted to be opened ing chamber 2, the nozzle being incommunica-` tion with the branch pipe 32 through a pipe 58.

The gaseous treating medium when grass or similar material is being-treated, may be air that is heated to the desired temperature in any suitable manner as by a coal or oil furnace, or it may b e the products of combustion of such a. furnace. The treating medium is drawn throughthe inlet pipe I6 by a suction set up in the apparatus-by the fan 28. The tangential nozzle I4 at the end of the pipe I6 directs the medium through the annular space between the cylindrical wall 8 and the cylindrical baille I2 and around the latter, and it passes in a rising, whirling and expanding spiral up through the treating chamber 2 and out through the outlet pipe 22..

The freshly cut grass or other material to be treated, may be dropped into the upper end of the magazine 4 by means of a conveyor (not shown) or other suitable means. During the lling of the magazine, the damper'4 38 closes the opening 36 at the bottom ofthe Amagazine vand the damper 40 is opened." When a full charge has been dropped into the magazine, the damper 40 is closed thus sealing the magazine. 'I'hereafter the material may be fed into the top of terial drops by gravity through the opening 36' and into the treating chamber 2. To insure that the pressure in the magazine 4 and in the treating chamber 2 are equal so that the material will freely drop by gravity, the damper 44 in the equalizing pipe 42 ls opened.

As the material drops into the treating chamber it immediately thoroughly mixes with and is held in suspension by the gaseous treating'agent. When the full charge of material has been dropped into the treating chamber 2, the dampers 38 and 44 are closed and damper 40 opened, the magazine being then ready to'receive the next supply of material. lAfter entering the treating chamber 2, the material is whirled in and by the gaseous treating medium, until the treating or curing process has been completed as predetermined by the operator. This -time element willl vary with the kind of material being treated and the temperature of the treating mediuml the temperature being controllable by the operator.

Thus the upwardly whirling current of the gaseous medium thoroughly mixes with and carries suspended in its path the material which is being treated. Upon reaching approximately the point of intersection of the conical lower wall and upper cylindrical wall of the treating chamber, the velocity of the treating medium has been lowered due to the expansion of the conical wall I8 to the extent that it may no longer effectively carry the material in suspension. Consequently, the material tends to drop through the treating medium to a point of higher velocity of the treating medium where it is again carried upwardly in the spiral path` of the medium. 'I'his results in all of the particles or blades of grass. or other material, being uniformly subjected to the treatment of the gaseous medium and insures uniform drying of the material.

To accelerate the velocity of the gaseous rnedium within the treating chamber, additional gaseous medium may also be directed tangentially into the upper portion of the treating chamber through a nozzle 56, or a multiplicity of such nozzles may be employed.

Owing to centrifugal force. the material'ls directed away from the lower end of the pipe 22, while the gas is free to pass upwardly through the pipe as indicated by the arrows.

When the material has been thus treated to the desired degree, the damper 48 is opened so as to cause the material to pass by centrifugalforce and by the velocity of the gas through the opening 46 anddrop by gravity into the collecting chamber 6.. Just prior to the opening oi the damper 48, the damper 54 of the equalizer pipe 52 may be opened so as to permit the gaseous medium to be drawn into the collector 8 with the material so as to expedite and insure the passage of all of the material into the collector.

Aftera time limit sulcient to allow all of the material to enter into the collector 6, the dampers 48 and 54 are closed and the damper 50 is opened permitting the material in the collector to fall by gravity therefrom into a truck or Wagon body, or on to a conveyor tobe taken to a desired point, thus completing the passage of the material through the apparatus.

Upon closing the damper 48, the damper 4U is also closed, and the damper 38 is opened permitting the next charge of material to be dropped into the treating chamber for treatment.

The fan 28 blows the gas through pipe 30 where all or part thereof may be diverted by the damper 34 through the branch pipe 32 where it is returned to the treating chamber. If part of the gas is allowed to escape and part returned to the treating chamber, the loss may be made up `by the heated air or products of combustion from treating chamber in a steady flow which rises in a spiral movement of varying velocity and carries the material in suspension therewith by its velocity and by centrifugal force applied against the gravity of the material. As the velocity of the treating medium decreases, the material drops by gravity to a point of higher velocity.

The treating medium continueson its path leaving the treating chamber to be returned in whole or in part to the initial point of introduction.

This action of the material in the treating medium allows contact and thorough mixing of the medium with the material, thus making the process highly efdcient and insuring uniform results. 'I'he material remains in contact with the treating medium until such time as the treatment is completed.

In the'case of grass or similar material and heated air as the treating medium, the heat ls transferred from the air to the grass and moisture in the grass is evaporated, and at the same time the air becomes a carrier for the water vapor liberated. I

I have found that in the drying of grass especially, it is advantageous to use products of combustion as a treating medium provided the combustion in the furnace employed is substantially complete, because carbon dioxide is present and the oxygen Vcontent is low. As the products of combustion are recirculated and reheated the gas becomes a mixture o1' products of combustion and steam. This combination produces an excellent drying agent" for material such as grass. It is essential that the temperatures of the mixture always exceed 212 F. At temperatures exceeding 212 F. and normal atmospheric pressure, the steam in the mixture is in a superheated state and therefore has the properties of absorbing large quantities of water vapor without danger oi reaching the dew point.

I have found that gas temperatures for drying grass may be as high as 1350 F. without injury to the grass provided there is sufficient moisture being vaporized to cool the blades of grass. Temperatures above 600 are advantageous in destroying virus fungi and bacteria. I have also found that as the grass approaches the dry state it is essential that the temperature of the grass does not exceed 275 F. and preferably 250 F. so as not to injure or burn the product.

In view of the foregoing, therefore. the temperature of the gas should be reduced from the high temperature, 1350 F., to a final temperature at the end of the drying cycle of 250 F. This is easily accomplished because the grass is dried in a batch and the quantity of gas in the whole system is relatively small. I have found in some cases that the source of heat may be completely shut 01T at some point in the drying cycle, the heated walls of the dryer being a suiiicient source of heat to prevent the temperature from dropping below 212 F. at which point condensation would occur.

I have found that the aforesaid method of suspending the grass in the current of gas and by recirculating part of the gas together with the aforesaid varying temperatures for the drying cycle produces grass in a dried state which retains its color, high protein value, is free from spores and bacteria, and is in every respect desirable for cattle feed. The high temperature used and the benets-of recirculation combine to produce dried grass at a high fuel efliciency.

My improved apparatus requires low initial expense for construction and setting it up, and low maintenance costs and high fuel efficiencies.

As will be evident to those skilled in the art my invention permits various modications without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

l. In an apparatus for treating material of the class described, the combination of a treating chamber' vertically arranged, having the lower portion thereof daring upwardly and outwardly in conical form and having the upper portion thereof substantially cylindrical, means for directing a current of a gaseous medium into the lower end of the treating chamber, means for causing the current to take an expanding spiral path as it travels upwardly through the chamber, means for withdrawing the gaseous medium from thewertical central portion of the chamber at a point spaced a distance below the upper end of the chamber, a magazine havnga port in its lower end opening into the upper part of said chamber. controllable means for opening and closing said port, said magazine having an opening in the upper part thereof through which a measured quantity of said material may be deposited in the magazine when said port is closed, controllable means for closing said opening when the material has been deposited in the magazine,

-ppei end the chamber, means for redirecting a part of the gaseous medium thus withdrawn from the chamber in a generally tangential direction into the upper part of said treating chamber, means for delivering material to the treating chamber, and means for effecting the discharge of material from said chamber.

3. In an apparatus for treating material of the class described, the combination of a. treating chamber vertically arranged, means for directing a gaseous medium upwardly through the chamber in a generally spiral path, a magazine for receiving the material to be treated having a port leading into the upper part of said treating chamber, means for opening and closing said port, a collector for receiving the material from the treating chamber having a port leading from the upper part oi. said chamber, and means for opening' and closing said port in the collector.

4. In an apparatus for treating material of the class described, the combination of a treating chamber vertically arranged, means for directing a current of a gaseous medium into the lower part ofthe chamber and for causing it to take an expanding spiral path as it travels upwardly through theA chamber, means for withdrawing the gaseous medium from the vertical central portion of the chamber at a `point spaced a distance below the upper end of the chamber, controllable means for admitting a measured quantity of the material into the upper part of the chamber at one side of the center thereof, and controllable means for effecting the discharge of the material from the other side of the upper part of the chamber after the entire quantity of material has been subjected to the treatment of said gaseous medium.

5. In an apparatus for treating material of the class described, the combination of a treating chamber vertically arranged, means for admitting a gaseous medium into the lower part of the chamber, means for withdrawing the gaseous medium from the upper end of the chamber, a magazine at one side of the chamber having a port in the lower end thereof leading into the upper part of said chamber, controllable means for opening and closing said port, said magazine having an opening in the upper end thereof,

controllable means for opening and closing saidopening, a conduit leading from the upper end of the magazine to the upper part of said treat-` f ing chamber, and means for opening and closing;

said conduit, and means for discharging the mai terial from said treating chamber.

the class described, the combination of a treating chambery means for directing a gaseous medium into the lower part of the chamber, means for withdrawing the gaseous medium from the upper part of the chamber, a collector at one side of said chamber having a port leading from the upper part thereof to the upper part of said chamber, controllable means for opening and closing said port, a conduit leading from the upper Iportion of the collector into said medium withdrawing means, means for opening and closing said conduit, and means for charging material into the treating chamber.

EDOUARD LE B. BENOIT,

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