US1415623A - Method of drying goods - Google Patents

Description

W. ATKINSON.

METHOD OF DRYING GOODS.

APPLICATION FILED OCT. 12, 1918.

Patented May 9, 1922.

initial vacuum after which the drying and WILLIAM ATKTNSON, OF BOXFORD,

MASSACHUSETTS, ASSIGNOR TO THE VACUUM COMPANY, OF SOMERVILLE, MASSACHUSETTS, A CORPORATION 01E MASSACHU- METHOD OF DRYING GOODS.

Specification of Letters Patent.

.Patented May 9, 1922.

Application filed October 12, 1918. Serial No. 257,855.

To all whom it may concern:

Be it known that 1, WILLIAM ATKINSON, of Boxford, in the county of Essex and State of Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Methods of Drying Goods, of which the following is a specification.

In certain types of drying it has been considered necessary, Where the goods contain much moisture, to provide a condenser'between the drier and the vacuum pump which shall condense the moisture collected by the air in the process. This has resulted in considerable expense because of the amount of power used to run the pump to draw the air through the condenser. My method is an improvement upon methods heretofore used so far as I know, in that vapor'laden air passes from the heating chamber to a condensing thamber where it drops itsmoisture and circulates backthrough the heater to repeat the operation, which is continued as below described, a tank being provided to drain off the water or other liquid of condensation. The use of a vacuum pump may thus be dispensed with except to draw the condensation proceeds without the aid of a pump as below described. I

My invention will be understood by reference to the drawings, in which Figure l'is a longitudinal sectiomand Fig. 2 a cross section online '22 of Fig.1. i The apparatus is divided into two chambers, one a heating chamber and the other a condensing chamber, both forming part of the same structure. The heating chamber in the accompanying drawing is lettered A and the condensing chamber of substantially the same size is lettered B. Both chambers as shown are cylindrical in shape. One wall a of the chamber A is preferably of steel and is surrounded-by a covering of heat-insulating material C which. may be attached to it in any convenient manner. The outer end of this chamber is closed by a closure a bolted to the wall a and it alsofis covered with heat-insulating material C so that substantially no heat can be lost from this chamber except perhaps at its forward end.- Its forward end during the heating operation is closed by a vertically movable bulkhead D which closes, when desired, the front end of the chamber A but not airtight. It runs in vertical ways and may be raised and lowered as required to carry out my process in any desired way as will be understood by one skilled in the art. It has a small opening (1 preferably near its top connecting the two chambers. --Both chambers may be provided with tracks A as shown in order that cars E loaded'with the material E to be, dried may be run into the chambers.

At the rear or inner end of the chamber A there is provided a heater. F connectedto a suitable steam supply and a fan or blower G, the whole arranged within a hood H open at the bottom as at it so that the fan G may draw air intothe casing H from below and blow it out through the coils F The platforms to the cars are preferably constructed of suitable width as at e to form a partition across the chamber, thus" making a duct (1 below the cars and requiring the air which chamber in the direction of the arrows so as to establish'constant circulation.

By means of this portion of my apparatus the bulkhead D being in position to close the chamber A. When the material is thoroughly heated the door D separating the heating chamber from the condensing chamber B is raised. This chamber B is not insulated in any way and will of necessity therefore be much cooler than the chamber A and consequently will condense anv moisture which the air from the chamber A may bring into it. The outer end of this chamber B is closed airtight by the gate 6, and from that end of the chamber leads" a pipe J, which is connected with (not shown) and has a valve 7' by which it may be closed. Connected to the lower end is circulated by the fan to pass around the a vacuum pump of the outer wall of the chamber B is; a pipe pipe connecting serve to draw ofi the contents of. the tank K when desired.

;To carry out my method by the use of this apparatus the material 'is placed on the cars,

which preferably are run into and out of lation of air in the direction indicated by the arrows through this chamber, which will gradually heat the goods to be dried. To make the heatpenetrate the material, for example a bale of cotton or the like, the vacuum pump having been started, a partial vacuum is drawn, say five inches, and then immediately let down to air pressure. This results in drawing out some, of the moisture from the bales, its place being taken by heat ed air when the vacuum is relieved] By doing this a number of times the material may be thoroughly heated to or above boiling at the vacuum it is planned to use in the final condensation process. 4

When the goods are thoroughly heated v the pressure in the chamber Bis reduced below atmospheric pressure by the pump to say ten inches or whatever amount is desired in the two chambers after the bulkhead D is raised to connect the chambers. The pump is then shut off by the valve 9' and the apparatus is left in that condition for such atime as experience has shown is desirable. The process then goes on inside the tank, that is to say, the moisture in the goods boils out and the circulation of air containing the moisture is' maintained by the fan G, which constantly forces air through the heater.

The bulkhead should then be opened wide 01" sulficiently to allow free circulation fr'om'one chamber to the other. The air is driven into the chamber B as shown by the dotted arrows where the moisture condenses because the chamber B is not and has not been heated and will never get as hot as the chamber A.

Circulation is constantly maintained by the fan and as the air and vapor pass into the chamber B and the vapor is condensed it is collected in the tank K, the steam coil during this period being still maintained at its original or at. any given desired temperature so jas-to ,ensure the maintaining of the temper'ature in the chamber A, the condensation i has been sufficiently'dried air at atmospheric maintaining the chamber.

When it is determined that the material pressure is admitted and the gate b is opened and the material removed the gate or bulkhead D being raised,'ifthat has not already been done, or removed. L

It is evident that this method may be carried out by other apparatus than that shown.

It employes features which I believe to be or increasing the [Vacuum in a free circulation of air between the two chambers and reducing the pressure in the two chambers below. atmospheric pressure, whereby the moisture in the goods will be vaporized and the air and vapor from said heated-chamber will mingle with that in the condensing chamber and the vapor will be condensed, and circulating the vapor-laden air in the two chambersiwhereby it will carry the moisture' from the heating to the condensing chamber, deposit it there and return to the heating chamber for further heating, absorbing and condensing.

2. The method of drying above described which consists in heating the goods to be dried to a predetermined temperature ina closed chamber at atmospheric pressure, reducing the pressure in said chamber to such apoint that the moisture in the goods will be vaporized and absorbed by the air in the chamber, causing the vapor-laden air to cir-- and returning the air to the chamber to be reheated and to absorb other moisture from the goods and continuing the process until the goods are sufficiently dried.

3. That improvement in the art of drying which consists in circulating hot air around the materialto be dried in a closed chamber until the goods are thoroughly heated to a high degree oftemperature then reducing the pressure to such a point that the moisture in the goods will. be vaporized and absorbed by the air in the chamber and then condensing the vapor therefrom, and passing the dried air over the goods again whereby the air will absorb other moisture'from the goods, and continuing the process untilthe goods are sufficiently dried.

4. That method of drying goods which consists in placing the goods in a closedchamber, heating the air therein at atmospheric pressure whereby the goods will be heated, reducing the air pressure and causing the air to circulate about the goods whereby the moisture will be withdrawn from the drop W cooling the air to cause. it to its moisture and reheating it whereby it will absorb more moisture from the goods and again cooling it and. continuing the moisture-absorbing and dropping process until the goods are substantially dried will 'be alternately withdrawn from th whereby the\sameair will be used throughgoods and taken up by the heated air, and 10 out the drying process; then condensed and the dried air reheated to 5. That method of drying goods under a take upmore moisture from the goods, and partial vacuum in a closed chamber, which the same air under a'partial Vacuum used consists in alternately heating and cooling constantly until the drying is complete. the air while under a pressure less than atmospheric pressure whereby the moisture WILLIAM ATKINSON.

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