US2367770A - Apparatus for removing moisture from liquid products - Google Patents

Description

J. M. HALL Jan. 23, 1945.

APPARATUS FOR REMOVING MOISTURE FROM LIQUID PRODUCTS Original Filed Dec. 8, 1938 3 Sheets-Sheet 1 li a/a ntofl sgp/i MzE a/L Jan. 23, 1945. J. M. HALL 2,367,770

APPARATUS FOR REMOVING MOISTURE FROM LIQUID PRODUCTS Original Filed Dec. 8, 1958 s Sheets-Sheet 2 67\ 6 79 9 45 I 2 n I 77 I 5 130 f 129 n 124 i I 125 I 13 g st 5% J21 @mmw Jan. 23, 1945. J, M. HALL 2,367,770

APPARATUS FOR REMOVING MOISTURE FROM LIQUID PRODUCTS Original Filed Dec. 8. 1958 3 Sheets-Sheet 3 90 J12 109 J30 5106mm.-

55 /0' 06 Josey/L M flax! Patented Jan. 23, 1945 APPARATUS FOR REMOVING MOISTURE FROM LIQUID PRODUCTS Joseph M. Hall, Chicago, Ill.,

a Concentrating Company,

Delaware assignor to Drying a corporation of Original application December 8, 1938, Serial No.

Divided and this application August 25, 1941. Serial No. 408,176

15 Claims.

This invention relates to a system to! dehydrating liquid products.

One of the objects of the invention is the provision or a new and improved system for dehydrating liquid products by the use oi a closed system for the dehydrating. fluid together with novel means for shunting a portion of the heating or drying fluid through an evaporator for concentrating the liquid product preparatory to dehydrating the same.

Another object of the invention is the provision of new and improved apparatus for dehydrating liquid products by the use of superheated steam and novel mechanism for cooling and collecting the dehydrated material.

A further object of the invention is the provision of an improved method of dehydrating liquid products by the use of superheated steam and with a maximum conservation of heat.

A still further object of the invention is the provision oi a new and improved apparatus for concentrating and dehydrating liquid products that is simple in construction, economical to operate, efliclent in use, comparatively easy to install and that is composed of a. minimum number of parts.

Other and further objects and advantages of the invention will appear from the following description, taken in connection with the accompanying drawings, in which Fig. 1 is a side elevation 01' the concentrating and dehydrating system, with the parts shown more or less diagrammatically, and parts in section;

Fig. 2 is a vertical section of the dehydrator and collector, with parts broken away;

Fig. 3 is a top plan view oi the construction shown in Fig. 2, with parts omitted for the sake of clearness;

Fig. 4 is a section on the line 4-4 of Fig. 2;

Fig. 5 is a plan view of the collector shown in Fig. 2. with parts broken away;

Fig. 6 is a vertical section through the upper portion of the dehydrator showing the atomizing or spraying head in osition therein, with parts broken away and parts omitted for the sake of clearness;

Fig. 7 is a vertical section of the spraying head and associated parts on an enlarged scale, with parts omitted and parts broken away;

.Fig. 8 is a section on the line 8-8 of Fig. 6;

Fig. 9 is a section on the line 9-9 oi Fig. 7;

Fig. 10 is a section on the line ill-Ill of Fig. 7; and

Fig. 11 is a side elevation of a modified form of nozzle.

In the concentrating and dehydrating of liquid products, it is necessary that a considerable amount of heat be available ior evaporating the moisture contained in the product. In order that any method of evaporation or dehydration be performed economically, it is necessary that the heat applied to the heating fluid be utilized to the maximum extent. The present invention will be disclosed as utilizing super-heated steam as the heating or drying fluid and this fluid is recirculated through the dehydrating chamber. The molsture evaporated from the liquid product is converted into super-heated steam which is also recirculated. The excess steam is removed from this dehydrating system by flrst shunting it through a steam jacketed evaporator and the resulting steam and condensate reconverted into steam under pressure, a portion or all oi which is used to operate steam motors for driving pumps and other mechanism used in connection with the dehydrating system. the exhaust or this mechanism being further used as a heating medium tor the feed water heater that supplies water to the primary boiler or steam generator.

Referring now to the drawings, the reference numeral Ill designates the concentrating and dehydrating system or apparatus which comprises a boiler or steam generator ii tor generating steam to be used as a drying fluid, a superheater I! for superheating this fluid, a dehydrator or evaporator 13 into which the drying fluid tor desiccating or dehydrating a. liquid product is conducted, a collector l4 for collecting the dried particles, a cooler or cooling mechanism Ill for cooling the collected dehydrated material, evaporator mechanism l5 for concentrating the liquid product preparatory to dehydrating the same, a reservoir it for supplying the product to the evaporator, a condenser ll for condensing the moisture evaporated from a liquid product in the evaporators, a vacuum pump ll for reducing the pressure in the evaporators and a feed water heater is for pro-heating the water supplied to the boiler or steam generator i i.

The boiler or steam generator I I may be or any suitable construction. In the form shown, it comprises a heating chamber 2| having a combustion chamber 22 in the front end thereof and a boiler 23 above the heating chamber. A bailie 24 within the heating chamber is adapted to direct the heat upwardly toward the boiler 23. An oil or gas burner 25 supplies fuel to the combustion chamber. The products oi combustion pass through flues oi the boiler 23 into the stack 28 as is usual in such constructions.

Steam from the boiler 23 is conducted by pipes 21 and 28 into the header or antechamber II or the super-heater l2. Steam from the boiler is maintained under pressure by adjusting the valves 31 and 32 in the pipe 28. This pressure may be maintained at any suitable amount. preferably such that it may be used to operate pumps and other motors used in the plant. By means or the valve 3|, the steam from the boiler 23 may be expanded into the antechamber 28 to such an extent that its pressure is preferably, though not necessarily, maintained at substantially that 01 the atmosphere or slightly above. The steam is directed by a fan 33 through the super-heater I: where it is very greatly increased as to temperature but its pressure is maintained at about atmospheric.

The superheater comprises a heating chamber 34 having the bullies 35' and 36 extending upwardly from its bottom wall and the heat exchanger 23a comprising the heating elements or tubes 31 in its upper portion. Attached from the upper wall 38 of the superheater is a baiile 39 extending downwardly between the badies 35 and 36. The firebox or combustion chamber 4| is provided with a suitable burner 42 and the highly heated products of combustion of this burner are directed in a zig-zag path among the tubes 31 of the superheater by the bailles 35, I9 and 38. These gases are discharged through a pipe 43 into the stack. The superheated steam is conducted through a conduit 44 to the dehydrator i3 and withdrawn from the dehydrator l3 and conducted back through the conduit 46 to the Ian 33 thus forming what will be termed a closed circuit for the dehydrating fluid, as will presently appear.

Suitable means are provided i'or concentrating the liquid product before it is discharged into the dehydrator 13. In the form of the construction shown, the primary evaporator 48 and a secondary evaporator 41 are employed for this purpose. The evaporator 46 comprises a casing 48 having artitions or tube sheets 49 and II spaced from each end thereof and in which a plurality of tubes 52, extending longitudinally oi the casing 48, are secured. The tube sheets 49 and II divide the evaporator into an upper header I! and a lower header 54. The space within the casing 48 between the tube sheets 48 and Ii among the tubes I2 constitutes what may be termed a heating or steam Jacket 150 and steam conducted from the dehydrating system is conducted to this jacket to heat the liquid product which is supplied to the header 54 from the reservoir 16 by the pipe 55. As shown on the drawings, a conduit 56 is employed for conducting steam from the separator 14 to the steam jacket 50 for evaporating moisture from the liquid prodnot contained in the evaporator 46, as will presently appear. This steam, on being condensed, or partially condensed, is withdrawn from the jacket through a pipe 51 and delivered to the feed water heater is for preheating the same preparatory to delivering it to the boiler 11.

The moisture in the form of steam generated in the evaporator 46 passes over into a liquid collector 58 through a pipe 30. Due to the agitation of the material in the boiling operation in the evaporator 46, particles of the liquid are carried over by the steam into the collector II and are directed downwardly by a'deflector 59 into the bottom oi the evaporator. The steam separated from these particles is conducted over to the asemvo steam Jacket 500 or the secondary evaporator 41 through a pipe III for further evaporating moisture from the liquid product in this evaporator.

The lower header 54a oi the secondary evaporator 41 is in communication with the header 4 through a tube Ii having a valve 62 therein for controlling the flow of condensate through this tube to the header I40. The collector 58 is in communication with the pipe 61 through a pipe 620 so that the liquid collected in the lower portion or the collector Iii is fed into the header 54a of the evaporator 41 along with the condensate from the header 54. Since the construction of the secondary evaporator 41 is substantially the same as that oi the primary evaporator 48, it is not thought necessary to repeat the description.

The steam introduced to the jacket 50a through the pipe 60 is adapted to evaporate further moisture from the liquid product contained in the evaporator 41. This may be done by reducing the pressure in the evaporator, as will presently appear. Due to the violent ebullition of the liquid, particles of the same will pas over with the generated steam through the passage 10 leading from the header 53:: into a collector 63 which is similar to the collector 58. A deflector 64 directs the liquid into the bottom part of the collector and permits-the steam to escape through a pipe 66 which leads to the condenser l1. The condenser I1 is in communication with the vacuum pump it through a tube or pipe 66.

The bottom header 54a is in communication with an atomizlng mechanism 81 of the dehydrator 13 through the pipes or tubes 88 and 89, as-

shown in Fig. l of the drawings. The amount of concentrated liquid material supplied to the dehydrator through the tube 69 is controlled by a valve 88. Fig. 1. A pump 1i in the tube 69 is adapted to deliver the concentrate to the spray mechanism under pressure. The lower end or the collector 63 is in communication "with the tubes 88 and 68 through a pipe 12 which conducts the collected liquid product to the pump 1|.

In order that the liquid product shall flow from the evaporator 48 to the evaporator 41 and that the steam evaporated from the liquid in the evaporator 48 shall be carried over into the evaporator 41 and shall evaporate moi ture from the liquid product contained in the vaporator 41, it is necessary that the pressure :1 the Jacket 500 and on the liquid contained i the header 54a be maintained less than that in the evaporator 46. For reducing the pressure on the liquid product contained in the evaporator 46, the heating jacket ills of the evaporator 41 is in communication with the exhaust pump 18 by means of a pipe 13 secured at one end in the jacket 50a and in communication with the pipe at its other end. A valve 14 in th pipe 13 is adapted to control the pressure within the evaporator 46 which is accomplished through the pipe 80, collector 58 and passage ill leading from the header 53 to the liquid collector 58. By properly adjusting the parts, the pressure in the jacket 50a of the evaporator 41 is maintained slightly below that in the evaporator 48 so that the vapor evaporated therein will flow into the heating jacket 50a oi the evaporator 41. The pressure in the evaporator 41 is considerably reduced owing to its connection through the collector 63 and conduit 85 with the condenser 11 and vacuum pump it whereb the liquid in the evaporator 41 will boil at greatly reduced temperature.

The liquid product is delivered by a suitable pump 1|, or the like, through the pipe 69 to the spray or atomizing mechanism 81. The spray mechanism comprises a. spray head 15, Figs. 6 and '7, rigidly mounted on a rotating hollow spindle I5, see Fig. 6, which extends upwardly through the conduits M and 45, Fig. 2, and is surrounded by a housing II which is rigidly secured to a plate 18, Fig. 6, which in turn is mounted on the upper wall of the conduit 45. The spindle is adapted to be rotated by a suitable motor I8 mounted on a plate 8| secured to the plat 18. The spindle I8 is hollow, as shown at 88, for conducting the liquid product to the spray head and may be attached to, or constitute a prolongation of, the armature shaft 82 of the motor, see Fig. 6. The housing 11 is adapted to prevent the dehydrating fluid from overheating the liquid product during its flow through the spindle.

Surrounding the housing 11 is a casing 84 having its upper end rigidly connected to the plate 18 as by being welded thereto and having its lower end tapered for engaging the housing 11 to which it is rigidly connected as by welding or the like. The casing 88 constitutes a brace for holding the housing 11 rigid relative to the plate I8. Slidably splined on the lower end of the spindle 18, see Fig. '7, is a hub 83 of the spray head 15. This hub is held in position on the spindle I6 by a bullet nosed cap member 85 having its tapered portion extending downwardly and havin an axial projection 81 thereon extending upwardly into a recess 88 in the'hu'b 83 and having internal threads for engaging screw-threads on the lower end of the spindle Hi. The cap 85 is provided with an annular shoulder 88 which is adapted to engage a corresponding annular projection 8| on the hub 83 for holding the parts rigidly connected together. The cap member is provided at its central portion with a cavity 82 which i in communication with the bore 88 of the spindle 18 and constitutes a small reservoir for liquid delivered thereto through said bore. Radial passages 88 extend to the recess 88.

Suitable bearings are provided for the lower end of the spindle 18. In the form of the construction shown, two sets of ball bearings 83 are employed for this purpose. These bearings are slidably mounted on the reduced lower end of the spindle I whereby the spindle may be removed when necessary or desirable. The bearings are mounted in a sleeve 84 which is provided on its upper end with a rabbet 95 for receiving the lower end of the casing TI to which it is rigidly secured as by being welded thereto. The lower end of the sleeve is provided with a cap 88 having an axial opening for receiving an upwardly extending pro- Jection 91 of the hub 83. The projection 81 is adapted to engage the inner race of the lower roller bearing for holding the roller hearings in position against a shoulder 88 on the spindle I8, as clearly shown in Fig. 'I of the drawings. The cap 98 is secured to the lower end out the sleeve 84 by means of the tapped screws 88. The cap 88 is provided with a recess in which a liquid seal IN is mounted.

The spindle I5 is rotated at high speed and in order to prevent heating of the bearings, these bearings are water cooled. As shown, the sleeve 84 is provided with an annular recess I82 and water is adapted to be circulated around this recess. The water enters through a pipe I83 and is discharged through a pipe I84.

Means are provided also for lubricating the bearings. As shown, a passage I85 leading to a cavity I88 above the bearings is provided with a Bil grease nipple I81 through which the lubricant may be introduced.

The hub 83 is provided with a plurality of radially extending arms or nozzle members I88 each having an axial bore I88 in communication with the recess 88 and the recess 82 in the hub 88 through the passages 88. The outer ends of the arms I88 are rigidly connected to an annular deflector member III which is' concave on its outer surface, as clearly shown in Fig. '7. The arms I88 are so constructed that they constitute vanes of a fan for exhausting the drying medium from the dehydrator, as will presently appear. The arms are so constructed that the flow of the exhaust will be uniform from the inner to the outer ends of these arms. In order that this may be accomplished, the fiat portion I I2 of the inner end of the arm," Fig. 9, is turned at a greater angle to the horizontal than the flat portion II3 of the outer end of said arms, Fig. 10.

The outer ends of the arms I88 are each provided with threaded sockets lit for receiving the inner threaded ends of the spray nozzles II5 which extend outwardly beyond the deflector member III. Each of these nozzles is provided with a bore I I6 which is adapted to aline with the bore I88 of the corresponding arm when it is attached to its supporting arm and the outer end of the bore I I8 is greatly reduced to form a nozzle or atomizer opening as at I". The high velocity of the rotation of these nozzles tends to atomize the liquid or discharges the same in the form of a spray in the dehydrator.

Liquid products vary so much in their fluidity and other characteristics that in order to properly atomize the same it is desirable tohave nozzles of different lengths and atomizer openings of different diameters. For instance, where the liquid product is thicker or more or less viscid, a nozzle of shorter length and larger atomizer opening is provided; such, for instance, as the construction shown at I I8 in Fig. 11. When thicker products, or products of less fluidity, are to be atomized, the nozzle H5 is unscrewed and nozzle H8 attached in its place,

The cap 85 is provided with a transverse opening II8 for receiving a tool for attaching or removing the cap. By means of this arrangement, the head may be readily removed by first removing the cap 85 and then sliding the head downwardly from the spindle 18. After the head has been removed the spindle I8 may be readily removed by disconnecting the pipe 88 from the motor, releasing the motor base from the plate I8 and moving the same upwardly. This is considered an important feature of the invention because the head and other parts of the mechanism must, be cleaned at frequent intervals, usually at least once every twenty-four hours when used for dehydrating food products.

Suitable means are provided for directing the superheated steam entering through the passage 44 downwardly across the liquid spray discharged by the nozzles. In the construction shown, the top wall I2I of the dehydrator chamber I3 has an axial opening in which is rigidly secured a guide member I22, Fig. 2. This guide member is in the form of a irustum of a cone having its side Wall converging downwardly With its lower end curved outwardly as shown at I23, see Figs. 2, 6 and 7. Opposite the guide member I22 is the deflector III. A downwardly tapered casing I24, see Fig. 2, extending through the upper wall of the passage 48 is rigidly attached to the bottom wall of the passage 43 as shown in said figure. It is also rigidly secured to the upper wall oi the passage I4 and forms a gas or steam-tight joint therewith. The lower end oi the casing I24 has rigidly attached thereto an annular reinforcing or strengthening ring I which has its lower end provided with an inclined surface I23 which diverges downwardly. The deflector I I Iis provided on its upper edge with a corresponding inclined surface I21 which converges upwardly. These inclined surfaces overlap each other and are in close proximity as clearly shown in Fig. 7 and by means oi this arrangement, the dehydrating medium which flows downwardly through the intake passage I28 formed by the conductor I22 and deflector III, will not tend to bypass into the exhaust passage I36 formed by theQasing I24. The steam, or other drying gaseous medium, in passing down the passage I22 between the directing member I22 and the casing I 24, will be directed outwardly and downwardly across the outer end of the nozzle IIB by the deflector III thereby atomizing the liquid product as it escapes through the atomizer opening H1.

The dehydrator is so constructed that it functions somewhat like a cyclone collector and in order that a greater portion of the steam, or drying medium, shall be separated from the dehydrated material after it is desiccated, suitable means are provided for causing the steam, when it is introduced into the dehydrator, to rotate about the axis of the dehydrator so as to centrifugally separate the solid material from the dehydrating fluid employed. As shown, the steam passing through the conduit 44 is conducted through a snail I29, that is, is caused to take a circular or spiral path about the axis of the collector and it continues to move in a spiral path as it passes through the intake passage I28 across the nozzles IIE into the dehydrator where it encounters the finely divided liquid particles that are being discharged by the spray head as it rotates at high speed, thereby dehydrating or reducing the moisture content of those particles.

, The high speed at which the nozzles rotate through the entering stream of drying medium and the friction between the incoming drying medium and the annulus or deflector III will cause an increase in the rotational velocity of the entering steam or drying medium. This spiral motion of the steam will cause the dried particles of the liquid product to be thrown outwardly by centrifugal force toward the walls of the dehydrator and will be directed by the conical wall I3l downwardly by gravity into a circular passage I32 at the bottom of the dehydrator, Fig. 2.

The intake 01' the ran 33 is connected to the passage 45 and this, together with the fan blades I08 of the spray head, will exhaust a greater portion oi this steam axially upwardly through the casing I24 from the dehydrator. As a result 01 this construction, the drying medium enters the chamber from the conduit 44 through a snail I28, moves downwardly in an outer spiral to the lower portion of the chamber, reverses and flows upwardly in an inner spiral in contact with the outer spiral and is discharged through the passage I into the discharge conduit 43.

The dehydrator I3 is provided with a channel I32 around its lower end for receiving the dehydrated material sliding down the inclined walls I3I thereof. The conical walls "I extend slight. 1y over this e as shown at I33. An inverted conical deflector member I34 has its lower edge extending slightly over the passage I32 as at I33 and its apex extends axially upwardly within the lower portion of the dehydrator for directing the particles falling thereon into the circular channel or passage I32. The overhanging portions I33 and I33 or the walls III and I34 tend toprevent the particles falling into the passage I32 from escaping back into the dehydrator, as will presently appear,

Where dehydration is completed within the chamber l4, the dried particles falling into the passage I32 are at such temperature that they must be cooled before storage in order to avoid agglomeration. The cooling mechanism 23 is located 'at any convenient position, either directly below the dehydrator or spaced laterally therefrom. If directly below, the dehydrated particles may fall by gravity into the cooling mechanism, but it located laterally thereof, as shown in the drawings, suitable means must be provided for conveying those particles to the cooling mechanism. Any suitable conveyor may be used for this purpose.

In the construction shown, which is by way of example only, a fluid conveyor is employed for this purpose. The use of a fluid conveyor necessitates the use of a collector for separating the dehydrated material from this conveyor fluid. The centrifugal collector I4, which is ol' conventional design, is employed for this purpose. The fan of the collector I4 has its intake in communication with the passage I32 through a conduit I31 for conveying the dry particles mixed with a limited amount of steam, or other drying medium, from the dehydrator over to the collector. In order that this steam, or other medium, shall remain dry or superheated, a suitable shunt is provided in the form of a passage or conduit I36 for shunting a portion of the heated drying medium from the conduit 44 into the passage I32 for raising the temperature of the steam therein and also for boosting the velocity or the steam around the channel I32 and through the pipe I31. The amount of steam, or other drying medium, directed through the passage I36 is adapted to be controlled by a valve I". Just sumcient heated drying gaseous medium or superheated steam is employed to insure the dehydrated particles remaining dry while being conveyed to the cooling mechanism, The conduit I33 directs steam, or other heated drying medium to the passage I32 at a point adjacent to, but not in communication with, a discharge passage I31 which conducts the steam to the collector I4. The passages I36 and I31 being adjacent to each other, the steam is caused to move around the passage, as will appear from an inspection of Fig. 4. This movement oi the steam will insure against the dried particles collecting in the passage I32 and obstructing free flow oi those particles. The mixture or steam and dried particles will be separated in the collector I4. The dry particles are discharged through the passage I38 and the steam discharged through the passage 58 which is tangential to the collector I4. The steam is conducted to the jacket 33 or the primary evaporator, as described above.

It will thus be seen that the steam circulated through the dehydrator for desiccating the liquid product operates in what may be termed a closed circuit and for convenience of description will be called the dehydrating circuit. In this circuit, through superheater I2 passes along the conduit 44 into the dehydrator I3 and back through the casing I24, conduit 45 and fan 53 to the superheater. There is also what may be considered a closed circuit for the heating fluid utilized in the primary evaporator 46 for heating the liquid products therein. In this circuit, which may be termed the evaporator circuit, steam from the boiler 23 passes through the pipes 21 and 28 into the antechamber 25, thence through the superheater or heat exchanger tubes 31, down the pipe I35, around the passage I32, thence through the passage I31, through the collector I4, into the passage 56, then int the heating jacket 50 of the evaporator 45, from thence the steam and condensate are conducted through the pipe 51 to the preheater I9, and from thence back to the boiler II, thus completing the circuit.

Under certain conditions it is necessary, or at least desirable. that a considerable portion oi the steam be taken from the primary heater II and introduced into the dehydrating system, and at the same time additional water he introduced through the valve I48, as. for instance. when milk is being dehydrated and it is tainted with objectionable odors, as wild onions, and the like. In such cases more of the steam generated in the boiler is continuously introduced into the system in order that the drying fluid be mixed with fresh steam for maintaining the drying fluid in a more or less uncontaminated condition.

In order to cool the material conveyed from the dehydrator, or evaporator chamber, it is discharged Irom the conveyor and separator I4 into the cooler 20. The cooler comprises a support I55 on the top of which is mounted the separator I4 and which also supports a cyclone collector I50. steam is discharged through the passage I38 into the collector I50 across the discharge passage I39 of a fan I which discharges air tangentially into said collector. This air cools the product and finally escapes upwardly through an axial passage I55. The collector I50 operates as a cyclone collector for separating the cooled solid particles from the air discharged from the fan III. This fan may be operated by an independent motor I42 and the air may be taken from the atmosphere or from a suitable source of conditioned air. The centrifugal separator I4 is adapted to be operated by a suitable motor I43, see Fig. 5. Since the separator I4 employed may be of any commercial type and since the details of this separator constitute no part of the present invention, it is not thought necessary to specifically describe the same any further than to say it is of the horizontal centrifugal type.

The cooled particles gravitate to the lower conical portion of the collector I50 from which they may be removed through a rotary valve I5l operated by a motor I52.

Since moisture is being continuously added to the system from the liquid product, it is necessary to continuously remove the same amount from the system. In the construction shown, this is accomplished by using steam through the pipe I45 from the boiler for operating pumps such as the vacuum pump II! where the steam from the pipe I45 enters the pump IB through the passage I45a and the pipe I45 discharges the exhaust. Where the steam necessary to operate the pumps and other motors is in excess of that evaporated from the liquid products, which it usually is, it is necessary to add fresh water to the system and this may be done through the pipe I41, the amount being controlled by a valve I48.

The preheater I9 is of the usual or any well The dried material separated from the construction and in the i'orm shown, the pipe 51 delivers the steam and the condensed moisture into the preheater and is pumped therefrom by the pump I49 Into the boiler. The preheater is adapted to be heated by exhaust steam entering through the pipe I5I and is discharged through the pipe I52. The exhaust steam may be taken from the pumps as from the discharge of the vacuum pump I5 through the pipe I or from other engines and pumps employed in the plant.

If it is desired to remove a portion or the concentrate, it may be removed through a branch pipe I5I, the flow 01' the liquid being controlled by a. valve I55.

When necessary or desirable, steam may be shunted from the boiler II into the jacket 55 or passage 55 for raising the temperature of the steam contained therein, this is done by manipulating the valve 52. In order not to create too much back pressure in the passage 55, the valve 32 is operated so as to cause the steam to expand in the pipe I44 so as to maintain the pressure therein below that in the passage 55.

In the operation of the system described above for dehydrating milk, the following was found to give satisfactory results. The pressure of the steam in the boiler II was whatever was necessary to operate the various pumps and other apparatus in the plant and was around 50 to '10 pounds. The "steam or vapor introduced into the dehydrator was around 400 to 450 F. and at very low pressure, about that of the atmosphere or slightly above. The cubical capacity of the dehydrator was about 5,000 cubic feet and the velocity of the steam was such that about 15,000 cubic feet was introduced into the dehydrator per minute. The powder was dicharged at around 225 F. and was cooled to F. The above is given by way of example only and it is not here intended that the words used shall be construed as words of limitation but merely as words of description of one form or the device that has proven practical.

While the dehydrator I8 and associated mechanism is disclosed as completely drying the sprayed particles, it is understood that by increasing the feed of the liquid product, or by spraying a fresh product into the chamber in sufilcient volume, the mechanism will function as known a concentrator for concentrating the liquid product.

This is a division 01' my application, Serial No. 244.642.

It is thought from the foregoing taken in connection with the accompanying drawings 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 details of construction may be made without departing from the spirit and scope of the appended claims.

I claim:

1. In an apparatus for concentrating and dehydrating liquid products. a steam generator, a dehydrator, a superheater for superheating steam from said generator, means for discharging a spray of liquid products into said dehydrator, means for discharging a stream or superheated steam from said superheater into the upper portion of said dehydrator in a downwardly moving spiral across said spray for dehydrating the particles of said spray, an evaporator for containing a liquid product, and means for conveying a portion of the steam from said superheater to said evaporator for concentrating said liquid product preparatory to spraying the same into salt. cehydrator 2. In a system for dehydrating liquid products, a dehydrator, means i'or delivering a liquid product in flnely divided particles into said dehydrator, a superheater, means including a conduit for conducting superheated steam from said superheater to said dehydrator and for discharging the same into the upper portion of said dehydrator across said particles for dehydrating the same, a second conduit for conducting said steam back to said 'superheater for reheating the same, an evaporator for containing a liquid product, and a passage for conducting steam to said evaporator from said superheater for concentrating the liquid product contained in said evaporator 33. In a system for dehydrating liquid products, a dehydrator, means for delivering a liquid product in flnely divided particles into said dehydrator, a superheater, means including a conduit for conducting superheated steam from said superheater to said dehydrator and for discharging the same across said particles for dehydrating the same, a second conduit for conducting steam back to said superheater for reheating the same, a steam generator, an evaporator for containing a liquid product, and means for recirculating an aqueous fluid through said generator, superheater and evaporator for concentrating liquid products contained within said evaporator preparatory to dehydrating the same.

4. In an apparatus for concentrating and dehydrating liquid products, a dehydrator, means for discharging a spray of liquid products into said dehydrator, means for discharging a stream or superheated steam across said spray for dehydrating the particles of said spray, an evaporator for containing a liquid product, means for shunting a portion of said steam passing through said superheater to said evaporator for assisting in concentrating said liquid product preparatory to spraying the same into said dehydrator, a cooler, a conduit for conducting the dehydrated products to said cooler, means for directing cool air across said products, and means for separating said products from said air.

5. In an evaporating and dehydrating system, a dehydrator, a steam generator, at superheater, means for recirculating steam through said superheater and dehydrator, means for spraying liquid products into said dehydrator across a stream of said superheated steam, a cooler, a conduit for conducting dehydrated material and steam from said dehydrator to said cooler, a conveyor for conducting superheated steam to said conduit, and valve means for introducing superheated steam into said conveyor and conduit for maintaining said product in dry condition during its travel from said dehydrator to said cooler.

6. In a system for dehydrating liquid products, a steam generator, a steam superheater, a dehydrator, means for sprayin a liquid product into said dehydrator, means for conducting steam from said generator through said superheater into said dehydrator for desiccating said liquid product, a channel extending around the lower end of said dehydrator, a cooler, a conduit between said channel and cooler, and means for introducing superheated steam into said channel for assisting in conveying the dehydrated product to said cooler.

7. In a system for dehydrating liquid products, a steam generator, a superheater, a dehydrator, means for discharging a liquid product in said dehydrator in the form oi a spray, means for discharging superheated steam across said spray tor dehydrating said liquid products, means for recirculating steam through said superheater and dehydrator, an evaporator for concentrating said liquid product, and means for recirculating an aqueous fluid through said generator, superheater and evaporator.

8. In a system for dehydrating a liquid product, superheated steam generating mechanism, a dehydrator, means for discharging a liquid product into said dehydrator in the form at a spray, means for discharging superheated steam from said generator mechanism across said spray, a plurality of evaporators arranged in a predetermined order ior concentrating said liquid product prior to its delivery to said dehydrator, a source of supply of said liquid product, means for conducting the same to said evaporators, means for conducting a portion of said superheated steam to one or said evaporators for concentrating said product by vaporizing moisture contained therein, means for conducting the vapor generator in said last named vaporizer to the one next in order 01' said Vaporizers for further concentrating said liquid product, and means for reducing the pressure on said product in at least one of said evaporators.

9. In a system ior dehydrating liquid products, a dehydrator, means for discharging a liquid product in said dehydrator in the form of a spray, means for discharging a superheated fluid across said spray for dehydrating the particles of said spray, means for withdrawing the major portion oi said fluid through the upper portion Of said dehydrator, a channel extending about the lower portion of said dehydrator, a cooler, and means for conducting superheated fluid around said channel for heating said dehydrated material and for conducting the same from said channel to said cooler.

10. An apparatus for dehydrating a liquid product comprising a dehydrating chamber, means for introducing a superheated steam drying medium at substantially atmospheric pressure into said chamber, means for spraying a liquid product-into said drying medium, a superheater, a, boiler, means for circulating steam in a closed circuit through said superheater and dehydrator, an evaporator, means for supplying a liquid product to said evaporator, means for conducting steam from said superheater to said evaporator for evaporating moisture from said product, means for conducting said steam in condensed form to said boiler, means for conducting steam from said boiler to said superheater, and a conduit for conducting steam from said system for use in other apparatus for compensating for the increase in steam derived from the moisture evaporated from said product.

11. In an apparatus for concentrating and dehydrating liquid products, a boiler for vaporizin a drying medium, a superheater for superheating the vapor of said medium, a dehydrator, means for discharging a spray of liquid products into the upper portion of said dehydrator, means for discharging a stream of superheated vapor from said superheater into the upper portion of said dehydrator in a downwardly moving spiral across said spray for dehydrating the particles of said spray, an evaporator for containing a liquid product, means for shunting a portion of the vaporized drying medium to said evaporator for concentrating said liquid product preparatory to spraying the same into said dehydrator, restoring at least a portion or the shunted drying medium to said boiler.

asemro 7 12. In a system for dehydrating liquid prodverting the same into steam and for conducting ucts. a steam generator, a steam superheater, a the steam through said superheater and dehydehydrator, means for spraying a liquid product drator and for conducting the dehydrated mainto said dehydrator, means for conducting steam teriai to said cooler, and means for cooling the from said generator through said superheater into 5 dehydrated material delivered to said cooler. said dehydrator, means for discharging said 14. In a system for dehydrating liquid prodsteam into the upper portion 01' said dehydrator ucts, a dehydrator, means for delivering a liquid for reducing said liquid product to powder form, product to said dehydrator in the form of flnely cooling mechanism, means including steam for divided particles, means for dehydrating said conducting hot dehydrated products in powder 10 particles by the aid of steam, a cooler, means for form from said dehydrator and delivering the heating said particles with steam and for consame to said cooler, and means for discharging ducting the same to said cooler, means for coolair onto said product for cooling the same. ing said particles with a current of cool air, and

13. In a system for dehydrating liquid prodmeans for separating the dehydrated particles acts, a steam generator, a dehydrator, means for 15 from said air.

spraying a liquid product in finely divided par- A t od for dehydrating a liq d pro uct ticles into the upper portion of said dehydrator, which comprises concentrating the product, atomasuperheater, means including a conduit for conizing the concentrated product into a stream of ducting superheated steam from said superheater superheated steam for dehydrating the particles, to said dehydrator and for discharging the same n heating the dried particles and conducting the in a downwardly moving spiral across said parsame to a distance by a current of steam, septicies for dehydrating the same, a second conduit arating the dried particles from the steam, cooli'or conducting the steam hack to said supering the dried particles with a cooling in heater for reheating the same, a cooler for disand finally separating those particles from the charging fresh air across the dehydrated product 5 cooling medium.

for cooling the same. means for circulating an JOSEPH M. BAIL. aqueous fluid through said generator and con- CERTIFICATE OF CORRECTION. Patent l Io 2,567,770. January 23, 1914.5.

JQSEPH H. HALL.

It is hereby certified that error appears in the printed specification or the above mnnberedpatent requiring correction as follons: Page 6, secand column, line 73, claim 11, after the word and coma "dehydrator,"- insort --and means for-; and that the said Letters Patent should .be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of day, A. 1). 191, 5.

Leslie Frazer (Seal) Acting Camnissioher of Patents.

asemro 7 12. In a system for dehydrating liquid prodverting the same into steam and for conducting ucts. a steam generator, a steam superheater, a the steam through said superheater and dehydehydrator, means for spraying a liquid product drator and for conducting the dehydrated mainto said dehydrator, means for conducting steam teriai to said cooler, and means for cooling the from said generator through said superheater into 5 dehydrated material delivered to said cooler. said dehydrator, means for discharging said 14. In a system for dehydrating liquid prodsteam into the upper portion 01' said dehydrator ucts, a dehydrator, means for delivering a liquid for reducing said liquid product to powder form, product to said dehydrator in the form of flnely cooling mechanism, means including steam for divided particles, means for dehydrating said conducting hot dehydrated products in powder 10 particles by the aid of steam, a cooler, means for form from said dehydrator and delivering the heating said particles with steam and for consame to said cooler, and means for discharging ducting the same to said cooler, means for coolair onto said product for cooling the same. ing said particles with a current of cool air, and

13. In a system for dehydrating liquid prodmeans for separating the dehydrated particles acts, a steam generator, a dehydrator, means for 15 from said air.

spraying a liquid product in finely divided par- A t od for dehydrating a liq d pro uct ticles into the upper portion of said dehydrator, which comprises concentrating the product, atomasuperheater, means including a conduit for conizing the concentrated product into a stream of ducting superheated steam from said superheater superheated steam for dehydrating the particles, to said dehydrator and for discharging the same n heating the dried particles and conducting the in a downwardly moving spiral across said parsame to a distance by a current of steam, septicies for dehydrating the same, a second conduit arating the dried particles from the steam, cooli'or conducting the steam hack to said supering the dried particles with a cooling in heater for reheating the same, a cooler for disand finally separating those particles from the charging fresh air across the dehydrated product 5 cooling medium.

for cooling the same. means for circulating an JOSEPH M. BAIL. aqueous fluid through said generator and con- CERTIFICATE OF CORRECTION. Patent l Io 2,567,770. January 23, 1914.5.

JQSEPH H. HALL.

It is hereby certified that error appears in the printed specification or the above mnnberedpatent requiring correction as follons: Page 6, secand column, line 73, claim 11, after the word and coma "dehydrator,"- insort --and means for-; and that the said Letters Patent should .be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of day, A. 1). 191, 5.

Leslie Frazer (Seal) Acting Camnissioher of Patents.

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