US2357648A - System of dehydrating liquid products - Google Patents

Description

Sept.'5, 1944.

- J. M. HALL I SYSTEM OF DEHYDRATING LIQUID PRODUCTS Filed July 2. 1941 I INVENTOR osg o/z MM -M:

ATTORNEYS.

Patented Sept. 5, 1944 PATENT oFFlcE SYSTEM OF DEHYDRATING LlQUID PRODUCTS Joseph M. Hall, Chicago, Ill., assignor to Drying &'Concentrating Company, a corporation of Delaware Application July 2, 1941, Serial No. 400,758

15 Claims.

- This invention relates to apparatus and process of dehydrating liquid products in a single stage system. 7

The principal object of the invention is the provision ofa. system for'dehydrating' a liquid product in a singledehydrating chamber without the necessity of pretreating the product.

A further object of the invention is the provision of a one-stage dehydrating system having novel means for converting the system into a closed or open system for the circulation of the drying medium. w

A still further object of the invention is the provision of new and improved mechanism for cooling the dehydrated material before the same is discharged from the dehydrating chamber.

Another object of the invention is the provision of a new and improved method for removing moisture from a liquid product and an apparatus for dehydrating said product that is simple in construction, inexpensive to manufacture, easily assembled, and that is effective in operation.

Other and further'objects and advantages of the invention will appear from the following description, taken in connection with the accomthe heater proper from the headers, as shown in Fig.1 is a section on the line 4-4 of Fig. 1 v

V dehydration and where the liquid product is dehydrated. in a single stage, the liquid product is either sprayed directlyinto the products of combustion withinthe combustion chamber of the heating furnace or the gaseous drying medium is heated 'to' 'an exceedingly high temperature. Such high temperatures may not be objectionable for certain products but in other products, it would, destroy some or all of the distinguishing v characteristics of the product.'

The present invention seeks to dehydrate a liquid product in a single stage within a single chamber and at moderate temperatures.

Referring now to the drawing, the reference character In designates a dehydrating system embodying the invention. The system comprises a furnace II, a heater l2, a chamber l3 for dehydrating and collecting the liquid product, and av fan M for discharging a drying medium through the heater forincreasing its temperature.

The furnace ll may be of the usual or any well. known construction and is provided with a combustion chamber [5 having, at its forward end, a conventional burner [6 for discharging a mixture of liquid fuel and air into the combustion chamber IS. The upper wall of the combustion chamber is provided, at what will be termed its rear end, with a grill or grates I! through which the products of combustion flow into the heater l2. The heater is mounted in the upper endof the furnace, in the usual manner.

The heater is provided with a header l8 at its forward end and a header 19 at its rear end. A pair of flue sheets or partitions 2| and 22 separate Fig. 1 of the drawing. Suitable tubes or flues 23 have their ends rigidly secured in the flue sheets and constitute passages through which the gaseous drying medium passes for heating the same. One or more baflles'24 are provided in the heater chamber for causing the products of combustion to take a zig-zag course through the heater. A conduit 25 connects the discharge of the fan with the header l9 and a conduit 26 conducts the heated gaseous drying medium to the combined dehydrator and collection chamber I3, as will presently appear.

Suitable means may be provided, if desired, for causing a forced draft through the combustion chamber l5. As shown, the heating chamber is providedwith an extension 21 into which the products of combustion flow after passing through the heater l2. A fan 28 is provided for withdrawing the products of combustion from the chamber 21 through an intakc conduit 29 of the fan. The discharge conduit 3| of the fan is adapted to discharge beneath the" grates or grill 32 of the combustion chamber I5. Extending upwardly from the discharge conduit 31 of the fan is a stack 33 through which some or all of the gas withdrawn from the chamber 2lv is adaptis air although it may be other gases, if desired,

but for the purpose of description, the dryingmedium will be assumed to be air in the following description.

Fresh a i a pted to be supplied to the fan l4 through a conduit 35 which is preferably pro-- vided, at its outer end, with a screen or fllter 35 for removing objectionable foreign matter from the air before it is introduced into the system. A valve 31 is provided for controlling the amount,

of fresh air introduced into the system.

The combined dehydrator'and collector l3 constitutes the sole means in this system for removing moisture from the liquid product. This chamber comprises an upper section 38 and a lower section 39. The upper section 38 comprises an upper cylindrical portion 4! and a lower tapered portion 42. The lower section 39 has an upper cylindrical portion 43, the upper part of which is flared and merges with the lower portion of the upper section 38. The lower portion or the section 39 is tapered as at and terminates in a discharge conduit; 45. The material collected in the conduit 45 is discharged onto a mechanical screen 45 through a valve 41 operated by a motor 48.

The lower portion 42 of the upper section of the V 53 is rigidly attached thereto in such a manner that the snail discharges through the conduit 52. The intake of the snail is connected to the conduit ii'so that heated air from the furnace is caused to-descend into the dehydrator in an outer downwardly moving spiral.

Suitable means are provided ,for conducting the drying medium from the dehydrator. As shown, 'a conduit 54, extending axially down through the snail 53 and rigidly attached thereto, extends'upwardly above the snail and is connected to a discharge snail 55 which discharges into a return conduit 55. The return conduit 55- is provided with a discharge passage 51 through which the drying medium may be discharged from the system. A valve 53 is provided in this passage for controlling the discharge of the air or other drying medium. The conduit 59 is also provided with a'valve 59 beyond the conduit 51 for controlling the amount of air flowing through said conduit. The conduit 59 is in communication with the inlet conduit of the fan l4. The

fan I4 is operated by a suitable motor 6| as is usual in such constructions. g

In most liquid products that are dehydrated, the temperature of the dehydrated product within the dehydrator is above that safe forstorage.

' Suitable means are therefore provided for cool-' 'tion 43 in the same direction in which the outer spiralof thedrying-mediumis flowing within this portion of the dehydrator. The fresh air introduced through the passage 53 will. not only cool the product but will, to a certain extent,

lower the percentage of moisture .in the drying medium because the fresh air will usually have a very low humidity. The fan 62 is operated by a suitable motor 64, as is usual in such constructions.

In the operation of the device,- the' path taken by the drying medium or theair may be traced as follows: T

From the fan I4, the air is conductedthrough the heater l2 where the-temperature is raised to. the desired degree and then passes into the snail 53 which causes it to. rotate about a vertical axis and it is then discharged through the annular passage 50' into the dehydrator where it movesdownwardly and radially outwardly forming what, for convenience of description,-will be termed the outer spiral. This outer spiral will flow downwardly and around the conical member 5| and beneath the same into th lower section of the dehydrator where it will continue to rotate and will then reverse and move upwardly in an inner spiral rotating in the same direction as the outer spiral.

through the upper section of the dehydrator and will be discharged through the inner conduit-54 into the snail 55 and from the snail 55 along the return conduit 55, a portion or all of which will escape into the atmosphere through the. passage 51 depending On the positionof the valves 58 and 59. If a portion of the air passes beyond the valve 59, it will mingle with the incoming air in the conduit 35 and be delivered back to the intake of the fan, thus completing its cycle of-movement.

not be recycled but all of it will be discharged at 51 and the entire air used in the process will be continuously introduced through the intake Q5 of the fan I4 in which event the valves 31 and 58 will be open and the valve 59 closed.

Suitable means are-provided for spraying the 1 liquid product into the outer downwardly moving spiral of air'or other gaseous drying medium. In the form of construction shown, a rotating head is employed for this purpose. The head 55 is 'mounted on a shaft 66 which may be, and

preferably is, attached to the armature shaft of a motor 51 mounted on and supported by the snail 55. The shaft 66 is hollow, as shown at 59 in Fig. 4, and is in communication with'a pipe or conduit 58 which conducts the liquid product from introducing air through its discharge conduit 53 1 conduit 53 delivers air tangentially into the por- The outer ends of the arms 12 are each praa reservoir 59. Thereservoir 69 may be located above the head 65 so that the liquid product will be provided for delivering the product to the distributor head, asshown in Fig. 1 of the drawing. 4 r The distributor head is provided with radially extending arms 12, Fig. 4, each of which has a bore 10 in communication with the hollow portion of the head and which in-turn is in communicationwith the bore or passage 60 of the shaft 55. The outer ends of the arms 65 are preferably connected together by an annular'deflector member 13 which is concave on its outer side for deflecting air entering through the passage 59 downwardly and outwardly'across nozzles' at 'the ends of :..th arms, as will presently appear.

This inner spiral will pass, upwardly through the sleeve or conduit 49 axially In certain types of liquid products, the air will a vided with detachable nozzles I4 for spraying the product intothe incoming air. Thelength of the rotating arms 12, or rather the diameter of the deflector I3, is such that the inner spiral of air may 'move upwardly through the space between the defiector l3 and the head 65 into the discharge conduit 54. In order to assist in the movement of the air and for accentuating the rotation of the inner column of air, the arms1-2 are oblong and so arranged that they function as fan blades, as shown more clearly in Fig. 5 of the drawing. These blades rotate in the same direction as the inner and outer spirals of the drying medium.

In tracing the path taken by the liquid prod-w uct, it is pumped from the reservoir 69 and delivered through the conduit 68 and the passage 60 to the hollow portion 80 of the head 65 0f the spray device and from thence passes outwardly.

through the passages 10 in-the arms into the spray nozzles 14 where it is sprayed into the incoming air, this air being heated andthe particles being very fine, the moisture is evaporated from the sprayed particles and the dehydrated. particles thrown by centrifugal force outwardly against the walls of the dehydrator and fall by gravity from the upper section of the dehydrator into the lower section and from the lower section; are discharged by the valve 41 into the mechani-.

' scribed above.

By lengthening the cylindrical portion 43 of the lower section, the finer material is more efficiently removed from the air. ing spirally downwardly into the smaller diameter of the lower sectiomhas its velocity increased and this, together with the 'fresh air entering tangentially into this section, further increases the centrifugal force of the medium whereby a very eflicient separation of the material from the air is effected.

e If it is not desired to dehydrate the liquid product to such an extent as to produce a dry powder but merely to concentrate the liquid, the feed of the pump, which supplies liquid to the spray head, is increased or less air is recirculated or both and the lower section 16 of the discharge conduit 45 is removed and the receptacle placed directly beneath the discharge conduit 45 for receiving the liquid concentrate. The pump H may be of the adjustable feed type or a valve 11 in the conduit 68 anterior of the pump ll may be employed for controlling the amount of liquid supplied to the pump.

While in the construction shown, the, dehydrator chamber is circular in cross-section, it is understood that for convenience in manufacture, it may be polygonal in cross-section. The expression circular in cross-section is intended to include the polygonal type since chambers having a large number of .sides approach the form of a circle in cross-section.

It is thought from the foregoing, taken in connection with the accompanying drawing, that the construction and operation of my device will be apparent to those skilled in the art. and that changes in size, shape, proportion and detail may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In an apparatus for dehydrating a liquid The air, in movsection and a lower section, said upper section being provided with an unobstructed cylindrical at its upper end and merging into the lower portion of the upper section and a tapered lower portion, means for introducing a drying medium into the upper portion of said chamber'and for causing the same to move downwardly .in said chamber and into said lower portion in ancuter spiral and then substantially all of it upwardly out of said chamber inan in-ner spiral, a rotating head for spraying a liqui'dproduct into said outer spiral, and means for introducing fresh air into said outer spiral within the lower section of said chamber for cooling the dehydrated product therein. I

2. In a dehydrating apparatus, a dehydrating chamber having a cylindrical portion and a tapered portion below said cylindrical portion, a conduit member extending axially of said chamber within the lower portion of said tapered portion. a cone-shaped deflecting member attached to said conduit member adjacent the upper end thereof, means for introducing a drying gaseous medium into the upper end of said chamber. and

for causing the same to rotate in a downwardly moving outer spiral outwardly. of said conduit.

and then to' ascend in an inner spiral through said conduit and upwardly from said chamber.

3. In a dehydrating apparatus, a dehydrating chamber having a cylindrical portion and a tapered .portio'n below said cylindrical portion and a restricted portion below said tapered portion, a conduit member extending axially of said chamber within the lowerportion of said tapered portion above said restricted portion, a coneshaped deflecting member attached to said conduit member adjacent the upper end thereof, means for introducing a drying gaseous medium intothe upper end of said chamber and for causing the same to rotate in a downwardly moving outer spiral outwardly of said conduit down into saidrestricted portion for dehydrating a liquid product sprayed therein and then to ascend in an inner spiral through said conduit and upwardly from said chamber, and means for introducing a current of fresh air into said chamber belowsaid. conduit for increasing the rotational velocity of said gaseous medium and for cooling the dehydrated product as it passes downwardly into the restricted portion of said chamber.

4. A method of treating a liquid product which comprises introducing a current of gaseous drying medium into a chamber, causing'the same to rotate in a downwardly moving outer spiral:

5. In a dehydrating apparatus; a dehydrator chamber comprising an upper portion and a lower portion, said upper portion having means for introducing a gaseous drying medium and for causing the same to move downwardlyin an outer spiral within said upper portion and then downwardly in an outer spiral downwardly within said lower portion and then upwardly inan inner product, a dehydrating chamber having an upper spiralwithin saldvouter spirals and out of said chamber, .a rotating spray for spraying a liquid through said heater and directly to said dehydra- 1 .tor and collector chamber, means for causing product into said outer spira1 only, and means for introducing a small stream of fresh cool air tangentially into the lower portion oi said chamber into said drying medium for cooling said product and for assisting in the rotation of said outer spiral prior to its discharge from said chamber.

6. In a dehydrating apparatus, a dehydrator chamberrmeans for introducing a drying medium into said chamber and for causing the'same'to movespirally downwardly and then substantially all of it spirally upwardly out of said chamber,

means for spraying a liquid product into the outer spiral only, and means for introducing a stream of cool. air tangentially into the lower portion-of said chamber above the lower end thereof for mixing with said medium and for cooling the dehydrated product before it is collected within the lower portion of saidchamber.

7. In a dehydrating apparatus, a drying chamber, means for introducing a drying medium in a hollow stream axially into said chamber and for causing the same to move outwardly. and

downwardly within said chamber in an outer spiral, a tubular member in the lower portion of said chamber supported axially thereof, said means causing said downwardly moving air to reverse and to flow spirally upwardly through the heated medium to enter said chamber in a downwardly moving outer spiral and for discharging substantially all of the same from said chamber in an inner upwardly moving spiral, a conduit'for conducting the medium discharged from said chamber directly back to said fan, a valve controlled discharge passage for said conduit, means for spraying a liquid product into the outer moving spiral only for dehydrating said product, means for discharging into the atmosphere a portion 'or all of the medium entering said last-named conduit, and means for introducing unheated fresh gaseous drying ,medlum tangentially into the lower portion of said chamber for mixing with said heated drying medium for increasing the speed'of movement thereof and for cooling the dehydrated product moving therethrough. t

11. ha dehydrating system, a single combined dehydrator and collector chamber having an upper section and a lower section, said upper section having an upper cylindrical portion and a downwardly tapered lower portion, said lower section having a cylindrical upper portion flaring at its upper end and merging with the lower portion of the upper section, said lower section having a tapered lower portion, a heater, a 'fan, a valve controlled intake passage for supplying fresh gaseous drying medium to said fan, means for conducting said medium from said fan through said lieater'and directlyto, said chamber, a small for receiving said medium and for directing the same downwardly into said chamber, means including said fan and snail for causing said medium to rotate within said chamber in an outer spiral downwardly through said upper section chamber comprising an uppercylindrical portion f and a lower tapered portion, said tapered portion terminating in a ,downward extension of therefrom for directing air traveling in a downward spiral into said downward extension.

9. In a dehydrating system, a single combined dehydrator and collector chamber, a heater, a

fan, a fresh air intake passage for said fan, a-

valve for controlling theamount of fresh air admitted through said passage, means for. conducting air from said fan through said heater and. directly to said dehydrator and collector chamber, means for causing the heated air to enter ing gaseous medium tangentially into said lower section of said chamber for cooling the dehydra'ted product within said lower section and for accelerating the movement of the drying medium rotating within said lower section.

said chamber in a downwardly moving outer spiral and for discharging substantially all of the same from said chamber in an inner upwardly moving spiral, a conduit for conducting air discharged from said chamber directly back to said fan, a valve controlled discharge passage for said conduit, means for spraying a liquid product into the outer moving spiral of air only for dehydrate ing said product, and means for introducing fresh cool air tangentially into the lower portion of said chamber for mixing with said heated air for cooling the dehydrated product and for increasing the speed of the outer spiral whereby better separation is accomplished.

10. In a dehydrating system, -a single combined dehydrator and collector chamber, a heater, a fan, a valve controlled intake passage for supplying fresh gaseous drying medium to said fan, means for conducting said medium'from said fan 12. In a dehydrating system, a single combined dehydrator and collector chamber having an upper section and a-lowersection, said upper sec- -tion having an upper cylindrical portion a downwardly tapered lower portion, said lower section having a cylindrical upper portion flaring at its upper end and merging with the lower portion of the upper section, said lower section having a tapered lower portion, a heater, a fan, a valve controlled intake passage for supplying fresh gaseous drying medium to said fan, mean for conducting said medium from said fan through said heater and directly to said chamber, a snail for receiving said medium and for directing the same downwardly into said chamber, means including said fan and snail for causing said medium to rotate within said chamber in an outer spiral downwardly through said upper ection into said lower section, said means causing said spirally moving drying medium to reverse and flow upwardly in an inner spiral in contactwith said outer spiral and out of said chamber axially thereof, a return conduit for conducting said medium directly back to said fan from said chamber, a valve controlled discharge passage for said return conduit, a rotating spray head, apertured arms radiating outwardly from said head, nozzles detachably connected to the outer ends of said arms and extending into said medium as it enters said chamber, means for supplying a liquid product to said head, arms and nozzles whereby the same is sprayed into the medium only as it enters said chamber, and means for discharging a cooling gaseous medium tangentially into said lower section of said chamber for cooling the dehydrated product within said lower section and for increasing the speed of rotation of the gaseous medium within said lower portion.

. 13. In a dehydrating system, a single combined dehydrator and collector chamber having merging upper and lower sections of substantially circular cross section and large and small diameters respectively, a heater, a fan, a valve controlled intake passage for supplying fresh gaseous drying medium to said fan, means for conducting said medium from said fan through said heater and directly to said chamber, a snail for receiving said medium and for directing the same downwardly into the 'upper section of said chamber, means including said fan and snail for causing said medium to rotate within said chamber in an outer spiral downwardly through said upper section into said lower section, said means causing said spirally moving drying medium to reverse and flow upwardly in an inner spiral in contact with said outer spiral and out of said chamber axially thereof, a return conduit for conducting substantially all of said medium directly back to said fan from said chamber, a discharge passage connected to said return conduit, a valve within said passage for controlling the amount of said medium discharged from said system through said passage, a rotating spray head, apertured arms radiating outwardly from said head, nozzles detachably connected to the outer end of said arms and extending into said medium as it enters said chamber,,means for supplyi g a liquid product to. said head, arms and nozzles whereby the same is sprayed into the medium only as it enters said chamber, and means for discharging a cooling gaseous medium into said lower section of said chamber into said spirally moving drying medium for cooling the'dehydrated product within said lower section, said cooling gaseous medium entering tangentially in the direction of movement of said drying medium. I

14. A method of dehydrating a liquid product and for cooling the dehydrated material, which comprises spraying a liquid product into a downwardly moving outer spiral of gaseous drying medium, causing the dehydratedmaterial to be separated from the medium by centrifugal :movement of said medium and material, causing said medium to ascend in said chamber in an inner,

spiral to-a point of discharge, introducing a cool gaseous medium tangentially into said downwardly moving outer spiral through the downwardly moving dehydrated material for cooling said material, increasing the velocity of said drying medium, and for reducing the relative humidity 01 said drying medium and causing said gaseous medium to mix with said drying medium and ascend with the same to a point of discharge.

15. In a dehydrating system, a dehydrating chamber having a cylindrical upper portion, a

tapered lowerportion, a more acutely tapered portion below said tapered portion and having its side walls merging into the side walls of said tapered portion, means for introducing a. drying medium into said chamber at its upper portion and for causing the same to flow downward therein in an outer spiral and then upwardly in an inner spiral to the discharge from said chamber. a cone deflector at the juncture of said tapered portion and said more acutely tapered JOSEPH M. HALL.

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