US1590273A - Method and apparatus for conditioning materials - Google Patents

Description

June 29 1926.

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D. S. BAKER METHOD AND APPARATUS FOR CONDITIONING MATERIALS Filed Jan.'l7, 1923 =2 Sheets-Sheet 2 anoentoz z zm-aks sqm Patented June 29, 1926. 1

UNITED STATES 1,590,273 PATENT OFFICE.

.DAVID S. BAKER, OF GREENWICH, CONNECTICUT.

METHOD AND APPARATUS FOR CONDITIONING MATERIALS.

Application filed January 17, 1923. Serial No. 613,241.

This invention relates to a method and apparatus for conditioning materials, and aims to facilitate the drying or otherwise conditioning of materials by subjecting them to contact with a gaseous medium having predetermined moisture content throughout the,

medium is recirculated, .fresh gaseous me-.

dium is introduced into the chamber while a part of the medium which is passed 'over the material is withdrawn fromthe chamber. It has been customary to provide dampers for controlling the proportion of the gaseous medium which is recirculated.

The desirability of regulating the moisture content of the gaseous medium in the chamber throughout the treatment has long been recognized. The only practical method heretofore used for securing such regulation has been to introduce a hygrometer into thegaseous medium during each treatment and to regulate the proportion of new gaseous medium introduced throughout the treatment in accordance with theindications of the hygrometer. To accom lish such regulation manually has require constant attention on the part of a skilled operator. To accomplish such regulation by automatic means controlled by the hygrometer has necessitated the use of very elaborate and expensive mechanism.

The method which I have invented makes possible proper regulation of the moisture content of the gaseous medium throughout the treatment without the inconvenience or expense involved in the methods previously used.

In accordance with my invention, a sample of the material is first tested to ascertain the amount of moisture given of! by the material during definite time intervals ofthe period required for conditioning the material. In the subsequent conditioning of'other masses of the same material, the proportion of the gaseous medium recirculated is varied at' definite time intervals, predetermined in accordance with the results and data obtained from the test so as .to maintain the moisture content of the gaseous medium, throughout the treatment, at that required for most eflicient treatment.

The invention includes also a sim lo and inexpensive automatic controlling mec anism for use in carrying out the new method.

In order that the invention may be clearly understood I will describe in detail a s cific method embodying it and also a speci 0 apparatus for use in carrying out the method. This apparatus is illustrated in the accompanying drawings, in which Fig. 1' is a diagrammatic sectional front elevation of a dryer provided with controlling mechanism embed ing the invention;

Fig. 2 is an enlarge front elevation of the controlling mechanism sectioned on the line 2-2 of Fig. 4;

Fig. 3 is a vertical section on the line 3-3 of Fig. 4;

Fig. 4 is a top view of the controlling mechanism shown in Fig. 1; and

Fig. 5 is a front elevation of a different type of dryer rovided with controlling mechanism embo ying the invention.

As a specific method illustrative of my ina material, where the object sought is to dry the material completely with the least possible consum tion of heat. The drying may be accomplished in a dryer of ordinary construction, such, for example, as that illustrated in Fig. 1.

The dryer shown in Fig. 1 consists of a. casing A enclosing a drying chamber B subdivided into two flow passages by a artition C. Above and below the partition C 'vention, I will describe the conditioning oi.

are supports D for the material to be dried.

At each end of the chamber B are steam pipes E for heating the-drying medium. which is usually air. 'A mechanically driven blower F is rovided for causing a circulation of the rying medium in the chamber.

At the top of the casing A are an inlet opening G and an outlet opening H. These openings are controlled by the dampers J and K, respectively. It is apparent that when both these dampers are closed, all the drying medium contained in the chamber B will be recirculated in the chamber by the action of the blower F. If, on the other hand, both these dampers are open, as shown in Fig. 1, fresh drying medium will be drawn in through the opening G, while some of the drying medium which has already passed over the material will escape through the opening H.

When, therefore, the dampers-J and K are in any position other than completely closed position, a part of the drying medium present in the chamber B at any given time is dischargedthrough the opening H and replaced by fresh drying medium drawn in through the opening G; while the remainder of the drying medium present in the chamber at said time is recirculated in the chamber. The ratio of that part of the gaseous contents of the chamber which is not discharged frem the chamber, but is re-used to the total gaseous content of the chamber will hereinafter be referred to as the proortion of the drying medium recircuated. The proportion recirculated at any time is determined by the position of the dampers J and K.

In order to accomplish the object sought in the specific illustrative method, that is, to avoid the waste of heat, the proportion recirculated should at all times be made as large as possible, while on the other hand, suflicient fresh drying medium must always be added to keep the moisture content of the medium in the chamber low enough for effective drying.

The first step of the method consists in drying a sample mass of the material and determining, for example, by means of a hygrometer, the amount of moisture given off by the material during definite time in tervals of the drying period. It will, ordinarily, be found that moisture is given off much more rapidly at the beginning of the period than near the end. From the data so obtained, it is then determined how large a proportion of the drying medium may be recirculated during each such time interval of the drying, without making the moisture content of the drying medium in the chamber too high for efiective drying.

The next step consists in utilizing the data so obtained in drying other masses of the same material. This step is carried out by placing such other masses successively in the drying chamber B, and during each treatment varying the proportion of the drying medium recirculated at definite time intervals, so predetermined in accordance with the data obtained in the first step of the method, that during each time interval of the treatment the proportion of recirculation is as large as it can be without making the moisture content of the drying medium in the chamber too high for effective drying. By such intermittent variation of the proporion of recirculation at predetermined time intervals, the moisture content of the drying medium in the chamber may be rethe drawings. The controlling mechanism may be used in connection with the type of dryer shown in Fig. 1, and arranged to uniform throughout controlling mechanism which is shown in vary the position of the dampers J and K at predetermined time intervals.

The controlling mechanism shown in Fig. 1 is mounted on the casing A of the dryer which has already been described. This mechanism comprises a time member a which is moved at a uniform, predetermined rate, and an actuating member I), which is connected with the dampers J and K. The time member and the actuating member are provided with cooperating engaging members, by means of which the time member moves the actuating member. The engaging members of the time member are removable so that the predetermined times at which the actuating member is moved and the amount of each movement thereof may be changed'in accordance with the nature of the material to be treated.

In the form illustrated, the time member a and the actuating member I) have the form of discs which are mounted side by side in a casing or box 0 which is secured to the top of the casing A of the dryer.

The actuating disc I) is fixed on a short stub shaft d rotatably mounted on brackets e secured to the bottom of the box 0. On

the periphery of the actuating disc are a horizontally toward the time disc a. The ac 'tuating disc I) is connected to the dampers J, K in such manner that the dampers are both completely open when the disc is turned so as to bring the word Open in front of the pointer g, and are both completely closed.

when the word Closed is brought in front of the pointer g. The connectlon between the disc I) and the dampers, which is illustrated in the drawing, consists of a pinion h fixed on the stub shaft d, a slide barz' bearing a rack is engaging the pinion h and connected to the dampers J, K by means of hinged connecting rods m. The dampers J and K are counterbalanced by weights n, n. These counter-weights and the friction in the connecting mechanism between the dampers in the actuating disc 1) cause the dampers and the actuating disc I to remain in any position in which they may be placed until some force is applied to move them.

The time disc a, as illustrated in the drawing, is rotatably mounted on a stub shaft 0 fixed on brackets p secured to the bottom of the box 0. On one side of the time disc at is a I a clockwise direction is determined byclock mechanism contained in a casing w and providing an escapement and a train of gears, one of which meshes with the gear '0. As this clock mechanism is of ordinary construction, it is not illustrated or described in detail herein. The clock mechanism is so regulated that when the spring 9 is wound up the time disc 0. turns at the rate of one revolution in ten hours. The spring 9 may be wound up by turning the time disc a in an anti-clockwise direction, as during such turning the pawl t slips over the teeth of the ratchet to.

In the periphery of the time disc a are forty equally spaced holes m. These holes are identified by figures 0, 4, 1, etc., stamped on the face of the time disc (1. ()n the clock casing w and the time disc a are fixed cooperating stops y which arrest anti-clockwise turning of the time disc when a figure 0 is opposite the pointer g.

A plurality of engaging members or pegs 2, 2' are provided for insertion in any of the holes w of the time dis: a. The pegs z are longer than the pegs a. When "one of the pegs 2 is inserted in one of the holes at, it projects such a distance that when, during a. turning of the time disc a, it encounters one of the teeth f of the actuatin disc b, it turns the actuating disc I) throug an are equal to twice the angular distance between adjacent teeth of the actuating disc. The

pegs 2 are of such length that when one of them is inserted in one of the holes w and engages one of the teeth 7 of the actuating disc I), the disc 6 is turned through an are equal to the angular distance between adjacent teeth. a

The operation of the device described and the proper positioningmf the pegs z, a may best be understood from a specific example. As an example, it may be assumed that it has been determined by a test that in order to maintain the moisture content of the drying medium at a desired value, the dampers J and. K must be regulated in accordance with this schedule: At start "Dampers closed two-tenths. At one hour Dampers closed four-tenths. At 2 hours Dampers closed five-tenths. At three h0urs Dampers closed six-tenths. At five hours Dampers closed seven-tenths. At eight hours Dampers closed eight-tenths. In order to adapt the device to regulate the dampers in accordance with this schedule, a long peg 2 is placed in the hole m, which is identified by the figure 1, a short peg a is placed in the hole as identified by the figure A, which is adjacent to the figure 2, and other small pegs z are placed in the holes a identified by the figures 3, 5, and 8, resp ctively. The,

time disc a is turned in an anti-clockwise direction until its turning is arrested by the stops so that the symbol 0 on the time disc is placed opposite the pointer g. The actuating disc b is'set with the figure 2 oppositethe pointer g. The material to be dried is placed in the chamber B, steam is admitted to the heating pipes E and the blower F is placed in operation.

During th first hour of the treatment, the dampers J, K are two-tenths closed because of the setting of the actuating disc I) with the symbol 2 opposite the pointer At the end of the first hour the peg a 1n the hole a: identified by the figure 1 comes into contact with a tooth f, and turns the disc. I) through the are twice as great as that which separates the teeth of the disc -b, so that the figure a of the disc I) is brought in line with the pointer g, and the position of the dampers J, K is changed to a corresponding extent. At the end of two hours and a quarter from. the beginning of the treatment, the peg z in the hole a: identified by the figure 1; adjacent to the figure 2 comes into contact with a tooth f and turns the disc 6 through an are equal to that which separates the teeth of the disc so'that the figure 5 of the disc 6 is brought in line with the pointer q. As the operation proceeds, the pegs 2 in the holes w identified by the figures 3, 5 and 8 ar brought successively into contact with the teeth It will be evident that this has the e ect of varying the position of the dampers J and K in accordance with the schedule previously given.

It is apparent from Fig. 1 that the construction of the dryer therein shown is such that a considerable proportion of the dry ing medium in the chamber B. is recirculated even when the dampers J and K are completely opened. This type of dryer is, therefor not satisfactory for handling materials which give off moisture very rapidly at any stage of the treatment. Such materials may be treated in the dryer illustrated in Fig. 5. a In the dryer shown in that figure, an opening L near one end of the a chamber B is connected to an opening M;

near the other end of the chamber by means of a conduit N in which the blower F is introduced. In the conduit N are two openings G and H, which are opposite each other. The openings G and H are, re-

spectively, the intak and the outlet openin the chamber passes out through the discharge opening H and is replaced by fresh drying medium drawn in through the opening G.

The dryer shown in Fig. 5 is provided with controlling mechanism identical with that which has been described in connection with the other views, except that only one connecting rod m is necessary to connect the slide bar 1' to the dampers because of the fact that the damp rs are secured together by the link P. It is apparent that the controlling mechanism, when applied to this dryer, may be used to vary the position of the dampers J, K from an open position, in which no part of the drying medium in the chamber is recirculated, to a closed position, in which all the drying medium in the chamber B is recirculated.

\Vhile the controlling mechanism which has been d scribed has been found adequate to control the moisture content with such accuracy as is required in the efiicient treatment 01 most materials, it is apparent that the controlling mechanism may be arranged so as to vary the position of the dampers at as small or large intervals of time as may be required and to cause each movement of the dampers to be as small or large as may be required. a

I wish it clearly understood that. the apparatus features of my invention are by no means limited to the construction and arrangement of the specific apparatus which has been illustrated and described, as many changes ma be made in this specific apparatus wit out departing from my invention. Thus, the form and position of both the time member and the actuating member may be changed, and connecting means other than the pegs illustrat d may be used to cause the time member to efiect movements of the actuating member at predetermined time intervals.

What is claimed is:

intervals, said engaging means bein 1. The method of conditioning material by treatment with a gaseous medium, which comprises circulating the gaseous medium over the material and recirculating a portion ofthe medium, while varying the proportion recirculated at definite time intervals so predetermined in accordance with means for circulating gaseous medium there,

through and for recirculating a portion of the medium, of a time member, means for moving said time member at a predetermined rate, and means automatically actuated by the time member at predetermined time intervals to vary the proportion of the gaseous medium recirculated.

3. The combination with a chamber having inlet and outlet openings, a damper in; each of said openingsand means forv causing a circulation of gaseous medium in the chamber and through said openings, of a time member, means for moving said time member at a predetermined rate, and means connected with both said dampers and automatically actuated by the time member to vary the position of the dampers at predetermined timeintervals.

. 4. A device for controlling the position of the dampers of a. treatment chamber, comprising an actuating member connected with said dampers, a time member, means for moving said time member at a predetermined rate, and means connecting the time member with the actuating'member in such manner that the time member effects move ments of the actuating member through predetermined distances at predetermined time intervals.

5. A device for controlling the position of the dampers of a treatment chamber, comprising an actuating member connected with said dampers, a time member, means for moving said time member at a predetermined rate, and engaging means on each of said members positioned to cause the time member to move the actuating member at predetermined time intervals.

6. A device for controlling the osition of the dampers of a treatment 0 amber, comprising an actuating member connected with said dampers, a time member, means for moving'said time member at a predetermined rate, and engaging means on said members adapted to cause the time member to move the actuating member through predetermined distances at predetermined time adjustable to vary said distances and said intervals.

7. A device for controlling the position of the dampers of a treatment chamber, comprising an actuating member connected with said dampers, a time member adjacent to said actuating member, means for moving said time member at a predetermined rate, and removable engaging means adapted to be mounted on the time member in various different predetermined positions and when so mounted to engage the actuating member at predetermined time intervals.

8. A device for controlling the position of the dampers of a treatment chamber, comprising an actuating member connected with said dampers, a time wheel adjacent to said actuating member and containing a plurality of spaced holes, means for rotating said time wheel at a predetermined rate, and removable pins each adapted to be in sorted in any of the holes in the time wheel and when so inserted to engage the actuating member at a predetermined time and to impart thereto the movement of the time the actuating wheel and containing a phi rality of spaced holes, means for rotating the time wheel at a predetermined rate, and pins each adapted to-be inserted in any hole of the time wheel and when so inserted to engage and partially rotate the actuating heel at a predetermined time.

In testimony whereof I have hereunto set my hand.

DAVID S. BAKER.

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