US1737068A - Dehydrator apparatus - Google Patents

Description

Nov. 26, 1929. J. M; YOUNGER DEHYDRATOR APPARATUS Filed Dec. 1927 4 Sheets-Sheet INVENTOR. L/ sflaUM. g/omye/ BY 7%, 5

A TTORNEY Nov. 26, 1929. .1. M. YOUNGER DEHYDRATOR APPARATUS Filed Dec- 1927 4 Sheets-Sheet I N V EN TOR. Joshua M (/ourzqez: BY 7% /Z. @M

' ATTORNEY Nov. 26, 1929. 'J. M. YOUNGER 1,737,068

DEHYDRATOR APPARATUS Filed Dec. 5 1927 4 Sheets-Sheet s Q INVENTOR.

k Josbu a M- you/m2 A TTORNEY Nov. 26, 1929. J. M. YOUNGER DEHYDRATOR APPARATUS Filed Dec. 1927 4 Sheets-Sheet 4 INVENTOR. (/OSfiuOM you/776v,

A TTORNEY Patented Nov. 26, 1929 UNITED STATES JOSHUA M. YOUNGER, OF OAKLAND, CALIFORNIA DEHYDRATOR APPARATUS Application filed December 3, 1927. Serial No. 237,395.

The invention relates to an improved dehydrator of the continuously operable type and to a novel dehydrating process which the apparatus is adapted to carry out.

A general object of the invention is to provide a dehydrating process by which a superior and particularly uniform dried product may be produced.

Another general object of the invention is to provide a dehydrating plant specifically designed for carrying out the process of the present invention in a manner which is particularly efficient, both thermally and mechanically.

A more specific object of the invention is to provide an improved preliminary sweat-- ing of a food material as a step in the dehydration thereof.

Another object of the invention is to provide for a positive and periodic reversible circulation of heated drying air through the food, whereby the dehydration of the food may be hastened and the product uniformly dried with a minimum amount of shifting thereof in the dehydration.

A further object of the invention is to pro vide apparatus of the character described, which comprises a succession of similar drying units which operate similarly and indea-o pendent-1y whereby the process may be carried out to a controlled degree.

A still further object of the invention is to provide an improved and particularly efficient means for heating the drying air.

Yet another object of the invention is to provide in association with the apparatus, means facilitating the maintenance of the relative humidity of the drying air at or be low an allowable value.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following descriptions of the preferred form of the invention which is illustrated in the accom- 45 panying drawings in which,

Figure 1 is a sectional plan of a dehydrator embodying the invention and showing the arrangement of the main floor with a portion of the latter broken away.

Figure 2 is a vertical sectional View taken through a fresh-air duct below the floor of the apparatus, the location of the section indicated by the line 2-2 in Figure 9.

Figure 3 is a side View of a portion of the showing of Figure 2 at the upper edge of a louver panel.

Figure 4 is a vertical section taken generally on the broken line 4-4 in Figure 1.

Figure 5is a vertical sectional view taken on the broken line 55 in Figure 1.

Figure 6 is an ei'ilarged side sectional view taken through a furnace and steam generator forming part of the apparatus and shown in side elevation in Figure 4.

Figure 7 is a sectional view taken on the line 77 in Figure 6.

Figure 8 is an enlarged fragmentary view of a portion of the showing of Figure 5.

Figure 9 is a partial plan of the apparatus taken at the plane of the main floor thereof, portions of the floor being broken away to expose the ducts.

Figure 10 is a fragmentary sectional view taken as on the line 10-10 of Figure 1 and 1 showing the relation of food-carrying trays as stacked for use in the apparatus.

As herewith particularly disclosed, the dehydrator of my invention comprises a housing structure or building 11, enclosing the apparatus and having a rectangular floor 12, side walls 13, end walls 14, and a ceiling and roof 16. Preferably, the walls and ceiling are formed of material which is a poor conductor of heat. Extending longitudinally and centrally along the floor and from the building at opposite ends thereof is a single line of track 17, along which trucks 18 are arranged to be rolled into, through, and out of the building, the opposite end walls being provided with suitable inlet and outlet doorways 19 and 20 respectively to permit such movement of the trucks and their loads. Doors 21 are provided for the doorways 19 and 20, and such doors are preferably arranged, when closed, to provide a relatively tight seal at the doorway openings.

As is usual in the art to which the present invention particularly relates, the material to be hydratedfruit, vegetables, etc.'is placed in like trays 22, which trays are arranged to be stacked on the trucks 18 for conveyance through the apparatus. The trays are rectangular and are formed with the longer sides 23 thereof higher than the ends 24, whereby when they are stacked with the sides 23 superposed, the ends 24 of adjacent trays in a stack thereof will be spaced apart vertically to permit a free circulation of air between the trays and through the stack longitudinally of the trays, it being noted that the tray sides 23 cooperate to provide a substantially tight wall. With the present apparatus, the trays are disposed transversely of the trucks 13 .whereby the permitted circulation of air through the stacks will be transverse to the line of the track. It will now be noted that the tray stacks 25 of the different trucks are preferably of the same height and extend to a point closely adjacent the ceiling 16. Furthermore, the truclrs are preferably no larger in plan than the trays, so that the stacks on successive trucks may abut at their sides defined by the tray sides 23. The doorways 19 and 20 extend to'the level of the ceiling 16 to permit the passage ofthestacks therethrough. When the apparatus is in use, a succession of trucks carrying the tray stacks 25 is arranged to extend longitudinally through the building 11, with the stacks of adjacent trucks abutting whereby the line of trucks and tray stacks defines a partition through the building, with the hereinbefore described passages between the trays providing substantially the sole communication between the portions of the building at the opposite sides of the line of loaded trucks.

The space of the building 11, it will now be noted, is symmetrically partitioned to provide various compartments. Extending inwardly from opposite sides of the doorway 19 for a distance corresponding to the combined width of whole number of trays 22, are partitions 26, which partitions in cooperation with the end doors 21 at one end and the wall provided by the tray sides 23 opposite the other end, serve to define a sweat chamber 27 in which the first step of the process of my invention is arranged to be carried out in a manner to be hereinafter described. Partitions 28 eX- tend transversely from the inner ends of the partitions 26 outwardly to the adjacent side walls 13 of the building, whereby rectangular compartments 29 are provided on opposite sides of the sweat chamber 27. Fan operating motors 31 forming part of the apparatus are disposed in the compartments 29, which compartments will hereafter be referred to as motor chambers. The remainder of the building is arranged to provide one or more dryer chambers 32--as here shown, transverse portions 33 are provided which extend from the opposite side walls 13 in coplanar relation and to the line of stacks, such partitions preferably lying in the plane determined by corresponding tray walls 23 of a stack. Preferably, but not necessarily, the number of stacks arranged to be disposed in a given chamber is a whole number multiple of thenumber of stacks of trays accommodated by the sweat chamber 27-as here shown, the sweat chamber 27 is arranged to accommodate two stacks and the two chambers 32 shown, each accommodate four stacks. It will be noted that each dryer chamber 32 includes the space occupied by the stacks defined between the planes of the transverse walls or partitions which define the chamber, and that the number of dryer chambers provided may be increased merely by appropriately lengthening the building 11.

Each of the dryer chambers 32 is arranged to have heated and hygrometrically unsaturated air circulated therethrough in a positive manner. For heating the air, radiators 34 are provided in each of the portions 36 of the dryer chambers which are defined at opposite sides of the stacks, the heat being supplied to said radiators in any suitable manner. Two radiators 34 are preferably provided in each chamber portion 36, such radiators being disposed on opposite sidesof rotary blowers 37 provided in the chamber portion 36. When, as here shown, the ceiling and stack are relatively high, a pair of rotary blower fans'37 is provided in each chamber portion 36, such blower fans being mounted in superposed relation in a frame 38 and being arranged forrotation in the same direction. The blower fans 37 are mounted on shafts 39 extending from the motor chambers 29, said shafts being operatively connected to a pulley 41 of a motor 31 as by means of a belt 42 connecting the pulley 41 with pulleys 43 provided on the shafts 39. A typical operative connection of the motor with the blower shafts is shown in Figure 5 of the drawings. The blowers are preferably disposed mediately of the chamber portions 36 and those in the different portions of a given dryer chamber 32 are arranged to be oppositely rotated. In this manner, when the blowers are operated, a continuous circulation of the drying air through the stacks and from side to side of the chambers 32 is effected, as is particularly indicated in Figure 1. Preferably, secondary stationary partitions 44 of sheet metal are utilized for effecting an even distribution of the circulated air with respect to the trays.

Since a repeated circulation of a given mass of air through the trays would tend to saturate it as to moisture content, means are preferably provided whereby the relative humidity of the air may be maintained at a value no greater than is desired. Accordingly, a fresh-air conduit 46 is provided beneath the floor 12, such conduit being directed generally longitudinally of the building, and having laterally extendingbranches 47 terminating at louvered openings 48 in the floor generally beneath each lower blower 37.

Preferably, and as shown, the louver panels 48 at the openings 48 are pivoted about axes parallel to the floor whereby they may, through the action of a stream of air passing therebetween, be directed in the general direction of motion of such stream. As particularly shown in Figures 2 and 3, the louvers 48 are hingedly secured at their lower edges and their free edges are held in equally spaced relation by means of a rod 49 engaged through slots 51 provided in the louvers and having stop members 52 disposed thereon at opposite sides of each louver. In this manner, the louvers will be caused to always move together and in a corresponding manner. Since the introduction of fresh and unsaturated air involves the removal of a substantially equivalent amount of the moistful air, outlet openings 53 are prefe ably provided in the side walls 13. Doors 51 are provided for the outlets 53, such doors being variably disposable whereby the effective size of opening provided may be adjustably varied. As here shown, a pair of doors 54; is provided for each chamber portion 36, with the doors disposed to deflect part of the air from the passing stream thereof. It will. of course, be obvious that the rate at which fresh air is introduced into the dryer chamber will depend primarily on the degree of opening and disposition of the doors 54. Preferably, hygrometers 56 are mounted in the chambers 32 whereby an attendant may be advised as to the hygrometric content of the circulated air and adjust the doors accordingly, it being noted that the apparatus is thermally most efficient if the hygrometric content of the air be maintained at a relatively high, but not saturated, value. The doors 5% are also utilized as a means of access to the chamber portions 36.

Preferably provided below the floor 12 at the sweat chamber 27, is a chamber 57, such chamber having disposed therein a heating unit 58. The heater 58 comprises a drum 59, into which the flame from a jet burner 61 is arranged to be projected and from which the smoke and heated air is arranged to be conveyed to and through the radiators 34 to thereafter exhaust through flues 62 protruding from the roof 16 at opposite sides of the building, Preferably and as shown, the va rious radiators at a side of the building are connected with a common fiue 62, and suction blowers 63 are operatively associated with the fines for positively effecting a circulation of heated air and fumes from the heater and through the radiators at a controllable rate.

And, furthermore, the conduits 64 which contion. In this manner, a certain amount of preheating of the fresh air passing through the conduits .46 and 4:7 is arranged to be effected both in the chamber and conduits.

Preferably, and as shown in detail in Figures 6 and 7, the heater drum 59 is surrounded by a water jacket 65, which jacket is arranged to function as a steam generating means for delivering steam through a conduit 66 extending upwardly from the jacket 65 and into the sweat chamber. A valved exit 66 is arranged to control the volume distribution of the steam to either side. A tank 67 having a float valve 68 therein, is preferably provided in operative association with the water jacket, whereby the level of water in the jacket may be automatically maintained.

It will now be noted that the sweating process as heretofore applied to produce to be dried, has consisted in a heating of the produce in air having a low relative humidity whereby a portion of the moisture of the produce is evaporated in the sweating process. But such preliminary treatment of the produce has been found deleterious thereto in that the resulting drying out of the surface of the produce usually hardens the same to thereafter actually hinder an evaporation of moisture from the interior of the produce. By introducing live steam into the chamber as taught by the present invention, the skin of the'produce is actually softened to open the pores thereof and thereby so facilitate the evaporation of water therefrom in the drying chambers as to insure the production of a uniformly dried product lacking a tough skin.

In practice, the operation of the dehydrat-or now described is as follows: With the heater 58 functioning to generate steam and to provide heat at the radiators in the manner described, trucks holding stacks 25 of trays 22 are run into the sweat chamber 27 from outside of the building, such trucks and stacks being preferably of a sufficient number to fill the chamber; the doors 21 thereat are closed, and the produce is subjected to a steam bath for an appropriate time. When the steam sweating process is completed for the contents of the tray stacks in the sweat chamber, the treated stacks are moved for- Wardly into the first dryer chamber 32 and another set of trucks with stacks of trays thereon is run into the chamber 27. It has been found that if the drying air be circulated through the trays in a constant direction,the produce will be unevenly dried and it is therefore necessary to direct the drying air against the produce from at least opposed directions. Heretofore it has been a usual custom to provide differently directed ir streams in successive dryer chambers and to move the stacks of trays forwardly into another chamber each time it is desirable to change the direction of air flow through the trays. In accordance with my invention, however, I accomplish the same result by periodically effecting simultaneous reversals of the rotations of the motors 31, whereby the blower fans 37 will act to reverse the circulation circuit in each dryer chamber, it being noted that the blower fans are designed for such reversal. In this manner, the necessary movement of the tray stacks is minimized, and a particularly compact structure is made possible. It is noted that the reversals of the fans may be efiected in any suitable manner, and that no means for the purpose has been specifically disclosed, as the specific means forms no part of the present invention. Generally, the drying process will require a considerably longer time than the sweating process, and in Order that the drying may be completed, the dryer chamber portion of the apparatus is considerably longer than the sweat chamber, thus, in the present instance, two stacks of trays which have had their contents sweated simultaneously may occupy four difiercnt positions in the dryer chambers while a like number of succeeding pairs of stacks is having their contents sweated. It will thus be clear that the dehydrating process now taught is particularly efficient and produces a truly superior prod net.

I claim:

1. In a dehydrator structure, a drying chamber defined above a floor thereof and extending transversely across the structure, conveyor means for removably disposing material to be dried in said chamber mediately between the sides thereof, means for effecting a reversible circulation of the air in said chamber through the said material and entirely in the chamber, a fresh air conduit beneath said floor and arranged to discharge into said chamber through openings provided in said floor at opposite sides of the chamber, and swinging louvers at said openings arranged to become automatically disposed to discharge generally in the direction of circulation of the air of the chamber thereover by reason of said circulation.

2. In a dehydrator structure, a drying chamber defined above a floor thereof and extending transversely across the structure, conveyor means for removably disposing material to be dried in said chamber mediately of the sides thereof, blowers at the sides of said chambers for effecting a reversible circulation of the air in said chamber through said material and entirely in the chamber, a fresh air conduit beneath said floor and arranged to discharge into said chamber through openings provided in said floor generally beneath said blowers, and swinging louvers at said openings arranged to be 0perated by the suction thereat created by said blowers to discharge generally in the direction of circulation of air induced by the blowers.

8. In a dehydrator structure, a drying chamber defined therein in which material to be dried is arranged to be disposed in spaced relation from opposite sides of the chamber, means for effecting a reversible and closed circulation of the air in the chamber, afresh air conduit arranged to discharge into said chamber through openings provided in the chamber floor adjacent said chamber sides, and swinging louvers at said openings arranged to become automatically disposed to discharge generally in the direction of circulation of the air of the chamber thereover by reason of said circulation.

In testimony whereof, I ali'ix my signature.

JOSHUA M. Yo'UNeEn.

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