US2142568A

US2142568A - Apparatus for and method of drying gelatinous substances

Info

Publication number: US2142568A
Application number: US13044A
Authority: US
Inventors: Thomas K Lowry
Original assignee: Darling and Co
Current assignee: Darling Ingredients Inc
Priority date: 1935-03-26
Filing date: 1935-03-26
Publication date: 1939-01-03
Anticipated expiration: 1956-01-03

Description

Jan. 3, 1939.

T. K. LOWRY APPARATUS FOR AND METHOD OF DRYING GELATINOUS SUBSTANCES Filed March 26, 1935 3 Sheets-Sheet l v |NVENTOR= THOMAS K. LOWRY ATT'YS Jan. 3, 1939. T. K. LOWRY 2,142,568

APPARATUS FOR AND METHOD OF DRYING GELATINOUS SUBSTANCES Filed March 26, 1935' 5 Sheets-Sheet 2 W m FIG-3. i

W Mi

n 11]" ll E 15: o0 2 fFla-s. 30 37 w INIVENTORR THOMAS K. LOWRY BY @x 2 WATT'YS,

T. K. LOWRY Jan. 3, 1939.

APPARATUS FOR AND METHOD OF DRYING GELATINOUS SUBSTANCES 3 Sheets-Sheet 3 Filed March 26,

Mm i

. FIG-7 INVENTORI THOMAS K LOWRY G 1 272W ATTYS I ///////////v I\\\\\\\\\\\\\\\& I I A I 7/, I2 I w II// I villi/I Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR AND METHOD OF DRYING GELATINOUS SUBSTANCES Illinois Application March 26,

9 Claims.

This invention relates to an apparatus for and a method of drying gelatinous substances, such as gelatin, glue and the like.

An important object of the invention is to provide a closed circuit duct arrangement for circulating a drying medium through a bed of glue pellets; the provision of means for varying the temperature of the drying medium to dry the glue in predetermined successive stages and operations; the provision of means cooperating with the duct system whereby the drying medium, such as air, may be taken in the duct system from various positions, and the provision of particular means controlled for presenting an unsaturated drying medium to the glue to absorb the moisture therefrom, to agitate the glue during the contact of the drying medium therewith and controlling the temperature of the drying medium.

A further object of the invention is the process of drying glue which consists in circulating a drying medium'through a bed of glue-pellets, regulating the temperature of the drying medium, increasing the temperature of the drying medium at various stages and operations, agitating the glue while in contact with the drying medium and to so treat the drying medium so that it will be capable of absorbing moisture from the glue.

Another object of the invention is the provision of an apparatus for carrying out the above objects to dry the glue sufficiently for commercial purposes and to prevent deterioration of the glue as well as controlling the drying and heating of the medium to successfully dry the glue.

Numerous other objects and advantages will be apparent throughout the progress of the following specification.

The accompanying drawings illustrate a selected embodiment of the invention and the views therein are as follows:

Fig. 1 is a detail top plan view of the improved drying apparatus.

Fig. 2 is a detail elevational view, partly in section, on the line 2-2 of Fig. 1.

Fig. 3 is a detail vertical sectional view on the line 3-3 of Fig. 1.

Fig. 4 is a detail vertical elevational view of the agitating means.

Fig. 5 is a detail top plan view of the agitating means.

Fig. 6 is a detail plan section on the lines 6-5 of Figs. 2 and 3.

Fig. '7 is a detail sectional view on the line l-I of Fig. 6.

1935, Serial No. 13,044

Fig. '8 is a detail sectional view showing a rotary table which may be used with non-rotating rakes or agitators.

The apparatus herein shown for the purpose of illustrating the invention comprises preferably a cylindrical chamber I which is suitably supported or mounted on supporting means H, II, and arranged or situated in a room or enclosure having a wall 12 in which there is an opening l3 leading to the atmosphere.

A duct H has communication with the upper and lower parts of the drying chamber ID as indicated at I and I 6 respectively, which parts are connected by an intermediate portion or part l1, Fig. 1. A transverse portion l8 of the duct may extend into the opening l3, communication with the atmosphere being controlled by a damper IS. A door 20 may be provided in the upper part l5 of the duct l4, and a second door 2! may be provided in the intermediate portion I! of the duct 14, Fig. 1. Y

A fan or blower 22 has a housing 23 which forms part of the duct system H. The fan is for the purpose of circulating a drying medium or fluid, such as air or gas, through the drying chamber and duct l4. Refrigerated coils or elements 24 and heating elements or means 25 and 26, Fig. 1, are arranged in the duct system H for controlling the drying medium or fluid both as to temperature and moisture. The apparatus and construction so far described permits for varied and practically universal operation, provision beng made for controlling and regulating the heating for correctly drying glue pellets in a predetermined preferable manner.

Glue in the form of small particles or pellets and including the so-called Pearl glue is deposited in the drying chamber through an opening in the top, which opening may be closed with a door 21. The glue so deposited falls upon a foraminous stationary table 28, Fig. 3, or any other perforated surface, such as a fine mesh screen. This table is totally arranged within the drying chamber! and is carried on an open framework 29.

Agitating means 30, Fig. 3, is driven by a drive shaft 3| through the apparatus or device designated generally by the numeral 32, Fig. 1. This agitating means comprises a central member 33, Fig. 6, having four legs 34 to which the arms or

rakes

35, 36, 31 and 38 are driven. The arm or rake 35 is relatively short, extending approximately one half the distance from the center to the outer periphery or edge of the chamber. The arms or rakes 31 and '38 each extend from the center to the outer edge, while the remaining rake I6 is longer than the rake but shorter than the

rakes

31 and 38. Rakes or agitators of different sizes, therefore, may be provided by adopting this arrangement. Each rake or agitator is provided with a series of spaced prongs II and 40. The prongs 39 are vertical or relatively straight, while the prongs 40, while being relatively vertical, are offset, being bent at H and 2, Fig. 4, thereby bringing the lower ends of the prongs 40 in a position away from the longitudinal center line of the rakes as clearly shown in Figs. 5 and 6. The prongs are adjustable as they may be readily twisted by merely loosening their holding nuts, Fig. 4. The prongs are therefore free to be shifted as required to produce a plow effect, if desired. Braces 43 are connected to rakes as shown in Fig. 5. The prongs on the various rakes may be arranged so that the prongs on one rake will be positioned between the space between pairs of prongs on an adjacentrake, thereby preventing the prongs on one rake from following in the furrows of an adjacent rake. This construction and arrangement of the agitator including the various sized rakes and the alternately positioned and arranged prongs prevents the glue on the table from piling up toward either the center or the outer edges and at the same time causes the glue to be thoroughly agitated, separated and commingled.

The dried pellets on the table at the conclusion of the drying operation may be deposited in the cone-shaped portion 44 at the lower end of the drying chamber, Fig. 3. A valve 45 is provided at the end of the cone to withdraw the glue therefrom whereby it may pass into a pipe I to a hopper or to some kind of receptacle or vehicle. Such fines as pass through the small openings in the table become dry because of the cyclonic eifect of the air in the chamber 44.

To withdraw or remove the glue on the foraminous table, there are provided longitudinal trap doors 41 and I! each of which extend from the center of the chamber to the outer edge thereof. These doors are individually dropped or lowered by operation of the respective handles 49 which rotate a rod 50 causing the linkage 5| to lower the door. When the handles 19 are operated, the doors will drop and the glue on the table will finally drop through the openings, being carried or pushed through the openings by the rotating agitators or rakes.

It is desirable, if not necessary, that the glue pellets to be dried be first subjected to a drying medium of a relatively low temperature, that is. at a temperature sufliciently low so that the/glue will not melt and become stuck together, but

yet sufficiently high to quickly evaporate the water in the glue. The medium of course must be such as to absorb moisture. The preferred temperature of the initial or first drying stage is in the neighborhood of 70 F. so that a skin will be formed on the glue particles or pellets preventing them from sticking together in a mass.

A later or second drying operation comprises subjecting the pellets to the drying medium of a somewhat higher temperature. This second drying stage must be such to evaporate the moisture from the pellets, but it must be low enough to keep from melting the glue or harming it in any way. The temperature for this stage should besomewhere in the neighborhood of 90 F. de

pending, of course, upon the kind or type of glue to be dried.

A subsequent or third drying operation consists in further extracting moisture from the pellets to make the glue dry for shipping and for use commercially, and consequently a still higher temperature is necessary. This third drying operation or stage may be higher than 90, but still low enough not to melt or otherwise affect the glue. A temperature in the neighborhood of around 110 F. has been found preferable for this stage of drying. During this last drying operation or stage, it is essential that the drying medium be not too dry, as such a condition would cause a case hardening of the outside surfaces of the glue pellets, and prevent the moisture in the centerfrom working out. Therefore, the same air or drying medium is circulated over and over again, a small amount being exhausted constantly to regulate the amount of fresh air or medium to be taken into the system. By employing this method it is possible to regulate the moisture distribution in the glue pellets so that it will be uniform and the pellets will be dried to approximately a ten per cent 10%) moisture basis. The different changes in air conditions are regulated by means of the doors or dampers I9, 20 and 2i.

Outside air can be admitted to the system through the opening l3 and the amount can be regulated by operating the damper l9. Thus, primary air may be drawn into the system through the opening 13 when outside weather conditions permit. The air taken in through the opening i3 is circulated by means of a blower it through the duct l4 and into the drying chamber I 0. The air thus passes through the portion ll of the duct at the bottom thereof, and then passes upwardly through the foraminous table 28 and then out through the duct H at the point indicated at l5. It is preferable, however, that the air be circulated through a closed circuit. Therefore, the air being circulated will pass through the refrigerated coils 24, lowering the temperature of the air and, consequently, removing some of the moisture therefrom by condensation. The cooled and moisture-ridden air then passes through the heating elements 25, where it again passes through the portion ll of the duct and again through the material. If, however, weather conditions do not permit, the primary air may be admitted to the system from the inside of the room through the door 2i or if desirable or preferable, the air may be admitted to the system through the door 20, although the door 20 is preferably employed as an exhaust, permitting some of the air to be discharged out of the said door. Therefore, the device is capable of many changes. Air may be taken in through the openings i9, 20 or 2!, or air may be discharged out of either of said openings. Furthermore, air may be taken in through the openings I! or 2! and some of it discharged through the opening 20. It can thus be seen that the invention is capable of several aspects, as outside air may be taken into the system through the opening I! where it will pass through a heating coil, through the glue and exhausted to the atmosphere through the opening 20 after the first stage of the drying.

When weather conditions are not suitable, the air from the first stage of the drying is continuously circulated through the refrigerating coils and in a closed cycle. The coils are capable of chilling the temperature of the circulating medium to approximately 45 F., and subsequently heat it up to the desired stage. The operationof circulation is continued until a good skin is formed on the outside of the glue pellets. The second stage of drying is substantially the same as the first stage regardless of the weather conditions, as air may be taken in either from the outside or from a room and then heated up to approximately 90 F., at which temperature it is passed through the glue and then exhausted into the atmosphere.

The third stage of drying is ordinarily done with air ranging in temperature from about 90 F. to 110 F. The invention, therefore, provides a method of controlling the temperature of the air or other drying medium, regardless of the weather conditions, and permits the outside atmosphere to be used in the primary drying stage if weather permits. r I

The first drying stage includes the taking in of air which is unsaturated and then heating this unsaturated air to approximately 70 F., so that the air is capable of absorbing moisture from the glue. This drying mediuni, heated to approximately 70 F., is then passed through the glue until a skin forms thereon, and then exhausted to the atmosphere. If the original incoming primary air is too hot for the original or primary drying stage, the air can be circulated through the system until the proper\ desired temperature is attained. Also, this primary air can bemixed with the room air, as well as outside air, and passed through the system. Regardless of where the drying medium is obtained. it is preferable thatthe drying medium is below a 70 F. dew point and then circulated through the pellets until a skin is formed on the glue. The second drying operation is substantially the same as the first drying operation, except the temperature of the drying medium is raised to approximately 90 F.

Also, the third drying operation is substantially the same as the aforementioned operations, except the temperature of the drying medium ranges between 90 F. and 110 F., or any other temperature'adaptable for performing the operation of drying without causing the glue to become overheated. However, this third stage is always conducted within a closed circuit; that is, only approximately five per cent. (5%) outside air is taken into the system, but the air within the system is circulated and re-circulated throughout the system, being subjected to the cold and heat treatments to rid the moisture from the air and then raise it to the desired temperature successively. By discharging and adding about five per cent (5%) new air every cycle, the air in the system is completely changed at certain intervals. In one apparatus already tried the air is changed every twenty (20) minutes as three thousand (3,000) cubic feet of air is exhausted and the same amount of new air added, the said apparatus mentioned having a capacity of sixty thousand (60,000) cubic feet of air per minute.

In Fig. 8 the table 28 is shown disconnected and is rotatably mounted, having a peripheral ring gear 60 which is driven by a driven gear il Thus,

instead of rotating the rakes or

agitators

35, 35, 31,

and 38, these members may remain rigid or fixed, and the table 28 rotated. This construction would give probably the same agitating eflect.

The invention, therefore, comprises new and there are mounted rakes or agitators of diflerent lengths, so that the glue will be continuously turned over and agitated, but at the same time be prevented frompiling up either to the inside or outer edges of the foraminous table. After the glue pellets have been sumciently treated and the proper amount of moisture absorbed therefrom. the pellets may be quickly and readily removed'by merely turning a handle, whereby the agitators will cause the material to be forced through openings and deposited in a cone-shaped hopper or receptacle where they are free to be delivered. The device is simple in construction,

can be readily and economically manufactured and operated, and the parts are not likely to become damaged or get out of order.

Changes may be made in the form, construction and arrangement of the parts without departing from the spirit of the invention or sacrificing any of its advantage and'ibe right is hereby reserved to make all such changes as fairly fall within the scope of the following claims.

The invention is hereby claimed as follows:

*1. The method of drying gelatinous substances which comprises passing air at a predetermined temperature into a closed chamber and through the gelatinous material until a skin is formed about the outside thereof, subjecting the material to a second drying operation by increasing the temperature of the drying medium, subjecting the material to a third drying operation, and agitating ,the material during all of said drying operations.

2. The method of drying glue pellets which consists in passing air at a predetermined temperature into a closed chamber and through the glue pellets until a skin is formed on the pellets, raising the temperature in the chamber after a skin is so formed thereon, subjecting the' glue pellets to a third stage of drying which consists in passing a drying medium of a temperature higher than the second stage to complete the drying operation, and agitating the material during all of said drying operations.

3. The method of drying gelatinous substances in a closed circuit which consists in passing air at a predetermined temperature through a predetermined quantity of gelatinous material until a skin is formed about the outside of the material, discharging and adding drying medium during the drying operation, subjecting the material to a second drying operation which consists in passing drying medium at an increased .temperature through the glue pellets, adding and discharging drying medium during the second drying stage, subjecting the material to a third drying stage which consists in passing a drying medium at a still higher temperature through the said material, and agitating the material during said drying operation.

4. The method of drying gelatinous substances which consists in passing air at a predetermined temperature through a predetermined quantity of gelatinous material until a skin is formed about the outside of the material, agitating the material during said drying operation, discharging and adding drying medium during the drying operation, subjecting the material to a second drying operation'which consists in passing drying medium at an increased temperature through the glue pellets, adding and discharging drying medium during. the second drying stage, nnally subjecting the material to a third drying stage which consists in passing a drying medium at a still higher temperature through the material, said drying medium employed in the third stage being subjected first to a cooling operation to remove the moisture therefrom and then heating the drying medium to the predetermined temperature and circulating and recirculating the drying me dium in the last stage within a closed chamber.

5. A batch process for drying gelatinous mate .rial in separate, individual batches which comprises passing a drying medium at a predeterminedtemperature into a chamber in which a batch of the material is present, passing the drying medium through the gelatinous material of each batch until a skin is formed about the outside of the material, agitating the material during the said drying operation, subjecting the material to a second drying operation within the chamber which comprises passing through the said chamber a drying medium of increased temperature, subjecting the material in the chamber to a third drying operation comprising passing .through the material in said chamber a drying medium at a higher temperature with the chamber substantially closed and forming a substantially closed circuit, and finally discharging the batch from the chamber.

8. A batch process for drying gelatinous substances by a plurality of drying steps in a substantially closed chamber which comprises supplying a drying m um to the material in said chamber, increasing the temperature after a predetermined degree of drying has taken place, and

continually mixing the gelatinous material during drying.

, 7. The method of drying gelatinous materials which comprises-passing a drying medium therethrough in a substantially closed chamber, continually recirculating the drying medium through the mass of gelatinous material, cooling and heating the drying medium to reduce the moisture content thereof, and continuously admitting a predetermined amount of fresh drying medium and releasing a portion of said recirculating stream at spaced points in the cycle.

8. The method oi drying glue pellets and the like which consists in air at a temperature of about F. adjacent a mass of the said pellets until a skin is formed thereon, subsequently passing air adjacent the said pellets at about F., and as a final step passing air adjacent said pellets at a temperature of about 1''.

9. The method of drying glue pellets and the like, comprising passing a drying medium therethrough at a relatively low temperature to form a skin on the pellets, subsequently increasing the drying power of the drying medium at a predetermined temperature, and continually mixing the pellets during drying.

THOMAS K. LOWRY.