Nòv. l1.2, 1946. ' _ ` R. v. HEusER ‘ 2,411,039 BRYING APPARATUS` WITH ‘AIR DESICCATING MEANS ÄND AUTOMATIC REGENERATING MEANS THEREFOR « ' ' ' . INVENTOR 41,1%/ u. #fz/sri, A'r‘roRNEY Nov. l2, 1946. ’ ' R. v. Hl-:usER - 2,431,039 DRYING APPARATUS WITH AIR DESICCATING MEANS AND AUTOMATIC REGENEHATING MEANS THEREFOR » Filed Oct. 12, 1943 , l 4 Sheets-Sheet 2 ATI' NEY y Nov. l2, 1946. R. v.-HEUsER _ DRYING ARPARATUS WITH AIR DESICCATING MEANS ' AND AUTOMATIC REGENERATING MEANS THEREFOR 4 Sheets-Sheet 3 Filed oct. 12. 1943 -. mvENToR ~ fag/2H //. ,eff-asf?, Nov. EZ, w45. à. v. HEUsER 2,4ì L03@ DRYING APPARATUS WITH AÍR DESICCATING MEANS AND AUTOMATIC REGENERATING MEANS THEREFOR Filed OC‘L. 12, 1943 ' 4 Sheets-Sheet 4 k65’ 605%@ 7 í là INVENTOR P41/9H V. Wfl/55A”, Patented Nov. 12, 1.946 12,411,039 'rais UNITE '- , 2,411,039` DRYING APPARATUS WITH `nEsIc- -Í oA'rING MEANS AND AUTOMATIC REGEN _ EnATING MEANS THEREFOR` . . . _ _ l Ralph V. Heuser, WeavervillavN. C. Application october 12, 1943, serial'No. 505,931 ~ _ ¿1 claims. (01.,34-50) . 1 The present invention relates to apparatus for be lubricated and it operateswithout’any atten . drying and desiccating materials with the aid of porous compositions capable of being desorbed or tion. It is an improvement over the drying device l described in my U. S. Patent 2,067,920 which is .non-automatic in‘operationïand requires a per ity in homes, laboratories,` hospitals, restaurants 5 son’s attention in several manipulations. ` - The present invention is based in part on the activated by heat. _ The invention will probably be of greatest util v and certain stores or work shops where an actual or potential need` exists for a compact, self-con followingl principle: Bodiesof adsorbent compo crackers, cookies, cereals, etc., once their con-` 4 current passing-through a system> of resistance sition, preferably in the` form of a molded plate tained drying device permitting small objects to (or a multiplicity of plates), take up the _moisture be rapidly dried and maintained at alow degree 10 liberated from the materials to be dried. The, of relative humidity. resultant gain in weight by the plate is instru In homes the apparatus wil1 be useful 'for stor mental in causing an electric circuit to be closed ing and preserving various food products such as by a sensitive electricswitch, the ensuing electric tain'er has‘been opened, Vin a crisp and fresh con 15 wires embedded within ,the plate or in close prox dition, hence preventing the same from becoming imity thereof for purposes ofremoving the ad soggy and’ unpalatable. It will also prevent the sorbed .water from the plate. When this is the - caking of powdered and granulated products such « case a >bimetallic strip opens the electrics'witch, as sugar, flour, salt and spices. Furthermore it _ the plate cools down and -is again in condition to will overcome certain diiliculties connected with 20 adsor-b nioisture. The plate fulfills, therefore, the the dehydration of vegetables in ovens bythe hot kdual role of functioning as an adsorbing lmedium air- drying process. Some of the dried vegetables and as an. organ of the control ymechanism of . which it forms a part. This mechanismis pro are very hygroscopic, hence in order to prevent them from reabsorbing moisture and becomein duced in the form of a balance, the plate being fected and deteriorated by molds, spores or patho _counterpoised by a' movable weight, by a cantilever 25 genic micro-organisms it has been the practice to spring o_r by a helical spring. _ , put the dried products in hermetically sealed con From' the above it is seen that the apparatus tainers. By use> of ,the present drying apparatus works in a cyclic manner. The onset of the de sorbing phase is made adjustable by changing the this inconvenience and expense can be avoided. In laboratories the automatic drying apparatus 30 moment created by the counterpoise. This is done would supplant or 'supplement conventional desic by changing either the distance of the weight» cators usually charged with sticky, deliquescent or from the fulcrurn, or by changing the leverage corrosive chemicals for absorbing waterfvapor. of the cantilever spring or the stiiïness of the The troubleand expense of replacing suchk chemi helical spring. Furthermore provision is also ' cals would be eliminated. Besides a more rapid 35 made for regulating the period during which the drying would be had as compared with desiccators electric current is caused to ñow through the . operating at maximum efficiency only when fresh- - heating system. ly charged. ' ~ _ 1 ` y The invention will be more readily understood In hospitals and first-aid stations the appara by reference to the accompanying drawings, `in , tus would beadvantageous for storing and main 40“ which like reference characters indicate'like parts. taining sterilized dressings, sutures, bandages as well as surgical instruments, Petridishes, etc., in ` In ythese drawings an aseptic' condition after sterilization, since very dry hair has a strongly inhibitory leffect, on the alongthe line I-I of Fig. 2, n . ' , Fig. >1 is a vertical cross sectional view taken ~ y growth and propagation of bacteria' and other 45fthe line 2.-2 of Fig.' l, dangerous organisms. ' ‘ Fig. 2 is a vertical transverse section taken along ' . Fig. 3\ is a cross sectional underside view taken The few aforementioned uses are merely illus- « ¿along the line 3-3 of Fig. 2„ l 1 trative of numerous applications in which an in Fig. 4 is a perspective view of the plate and expensive, reliable drying apparatus is needed.` accessory parts shown inv Fig. 1, 2, 3," ~' 4 `_ One of the principal objects of the inventionis,l 50 Figßâ, Fig. `6 and Fig. 7 depict I_three positions therefore, `to provide an inexpensive, reliable andl ` of the link mechanism at different stages of the eñlcient apparatus for drying and desiccatingma ` `*drying operation, terials- in the vabove' `mentioned relationships. ` Fig. 8 is a longitudinal view of an adsorbant Other objectsV of the invention will be apparent ‘ plate A'with gravitational control mechanism, from the following description thereof. l ’ 55’Í Fig. 9 is a perspective view of the lever shown The present drying apparatus 'is simple in de sign, noiseless inoperation andv does not give rise yinl“i'g.‘8, v / f Fig. 10 is a front'eleva'tion vand Fig. 11 va plan to radio disturbances. `It has no moving elements L view of four depending plates coupled together ' subject yto’ wear> nor `intricate Aparts .likely to get and a ' control mechanism based on the use ofk a out of order.- Furthermore it‘does not'require to 6c helical spring. ‘ ` ‘ 2,411,039 . y ï . 3 .The apparatus according to lthis invention con sists essentially, as shown in Fig. 1 of a container I subdivided .into two compartments 3 and 4 by' ' a horizontal partition 2. The lower compartment 3 servesasv a receptacle for the materials to 'be dried, and these may be introduced and with drawn through a hinged door 5, around the rim ‘of which is iitted a resilient gasket 6. Doory 5 , . 4 y' , » 20 in a fixed position and thus insure the partial weight of the plate to exert its action on the spring 25 always at the same point once the proper ad- - justment has meen made. For this purpose the cups 23 secured'to angle 24 can «be moved in the axis of the plate towards or away from the fiat spring 25, by/ causing the ‘angle 24 to slide on brackets 2,6/in and out upon turning the screws 21 which are provided with locknuts 28. 'I'he plate ' also`~is provided with a bolt and latch (not shown in the drawing) permitting the door to be closed u 10 is supported at the opposite end of its length by the blade 25, of suitable resiliency, via a curved metal tightly. Partition 2 is designed as a narrow shelf - strip 29 secured centrally to the underside of plate within the container I to accommodate a two wingedvdoor 1 capable of being tilted about pivots 20. 8 in one direction only, as clearly indicated in the to a base fixed on the wall I, of the container. . The spring 251s attached at its other end drawings. 'I'he top of the container I is provided 15 On the said base is also fastened the bracket 30. When'the spring blade 25 is mounted on the base ' with a similar door 9 which, for the sake of brevity will hereinafter be designated as “upper' door” - as distinguished from door 1 hereinafter referred ‘ it has sufficient upward tilt that it will assume a -substantially horizontal position 'upon being 'g weighted down by the plate 20 after installation `pivots` I0 but `only in thel direction opposite to 20 of the same. The distance of the center of the to as'v “lower door”. Upper door 9' is tiltable onl that of the'lower door_1. These two doors are suitably linked together in such manner that when one is open to the fullest extent possible the other plate 20 from cups 23 advantageously is greater than the distance to where the strip 29 touches plate during the desorption phase from passing into the lower compartment 3 provision is made bell crank 32. One armfof bell crank 32 touches the underside of blade 25 while the other arm for the sudden closing of the lower door 1 as s_oon v bears a setscrew 33, .positioned opposite a bime the spring 25, ~ As shown in Fig'. 2, the bracket 30 supports one is closedtight and .Vice-versa. _ ~ In 'order to prevent moisture liberated from the 25 end of a light shafting 3l on which is'secured tallic strip 34. To shaft 3| is also rigidly secured , ' action of a mechanism _which will be described 30 an arm 35 bearing a small permanent horse-shoe as the upper door 9 has begun to open by the later.A The titling movement of the lower doorv 1 yis made dependent upon the movement of the upper door 9 through the intermediary of a link IJ and a pawl I3. The link II consists of tWo narrow strips of metal, and it is fastened to the magnet 36. The slight downward deilection of the spring'25 (brought about by moisture ad sorption of plate 20) causes the magnet to ap g proach the iron armature inside a Mercoid switch ’ 31, mounted on the angle 38. . Another,Y somewhat sturdier bimetallic strip 38, underside of the upper door 9 and I2 in a free fastened to bracket 40, surmounts the plate 2li swinging manner. The pawl I3 is suspended from the lower- extremity of link I I and it swings freely " in a longitudinal direction. In its middle section 'strip 30 bears a heating element 4I consisting of on pivot ’I4. At certain periods of the cycle the pawl I3 engagés the latch I5 which is rigidly at 40 6 to 10 tunis of resistance wire wound around a thin asbestos bobbin, the wiring also being insu tached to the rupperside of the lower door 1. At lated -by asbestos or glass iiber fabric on the out another stage. of the operation pawl I3 will be side in such a manner as not to interfere with - seized through the intermediary of the projecting the curling motion4 of .the bimetallic strip under finger by' a` hook I1 support ed n a free-swinging the influence of heat from the two sources. Through a perforation near the‘free end of the strip 39 a metal rod 43 projects a short distance while its club shaped enlargement 42 rests on top of the strip. The other end of rod 43 passes culate -fr'eely between the two compartments 3 and“ 4, as 'illustrated in Fig. 5. When subsequently 50 through agidef“ and at the extreme end of -rod 43 a cupy 45 is attached which holds a polished Ithe upper door begins to open, as shown in Fig. steel ball. The latter bears against a wing of 6, the linger I has been seized by the hook I1 the upper door 3, causing the ylatter to be opened therebyfcausin .the curved end of pawl I3 to when the electric> current passes throughthe ele free itself i'rom latch l I5 and causing the lower door 1 to suddenly fall shut in which position 55 ment 4I _and the plate 20. A counter-weight 46, mannerat'point Iscr the bracket I9.‘ _ _ , . During’the absorbing- stage vof the plate .the upper door 9 is closed and the lower door 1 re mains ,cpen'w'hereby the air is enabled to cir it then resides during the entire desorption stage „ of the plate. As. the upper door 9 opens wider ' at this time link I I -and pawl I3 will descend lower, fastened to the inside of- one of the'wings of door 9, serves as a means to insure the spontane iinally slipping over the top of latch I5 and re»l . ous closing of the door 9, when the rod’43 re treats to its normal position related to the ad engaging it-on its underside, lso that when the 60 sorbing stage of plate20. Counter-weight .46 isV iixed o_n the wing opposite to that'which carries upper _door begins to close it will carry with it the lower door 1 and open it gradually. ' Dur the-- link II and pawl I3. ing itsupward travel the finger I6 of pawl I3 will clear .the hook I1 by pushing it slightly ,to the'topy of container I serves as a. means to po A rim 41 surrounding is then again in positiongto trip the‘ pawl I3 when the'subsequent opening'of the upper door ` air readily to escape into the open when the door sition a detachable hood 48 preferably made of ward the~.wall of the container. `The hook I1 65 perforated metal so as to allow moisture-laden loccurs. .v `_ ' ' .. 8 has opened. The electric current- enters the ¿apparatus through socket l49, the circuit wiring being diagrammatically indicated in Fig. 2. compartment 4 also houses the .adsorbent plate' 20 in_the interior 4of which is -embedded .70 As shown' in Fig. 8, which illustrates another embodiment of the present invention as it con a’gstretched coil’of electric resistance wire 2|. At cerns- a modified form of the control mechanism, one end -of its` length plate 20 is supported on two the same manner of -positioning the plate 20 by prongs 22, Fig. 2, by smallI cups 23 of glass or prongs 22 and cups 23 is employed as in the -metal.,_vWhile the prongs 22 are free to move i 'aid cups 23, yet the prongs also hold the plate 75 previously described design; illustrated in Fig. 2, 2,4111,oa9 ' Fig. 3 and Fig. 4. In the present instance, how ever, a metal disc 50 secured to the underside ' of plate 20 rests on the tip 5I of an upwardly curved lever arm 55 (Fig. 9). A pin 52 secured to a bracket 5_3 furnishes the fulcrum for the le ver. -The other arm of the lever bears a sliding weight 54 to oppose the force exerted by the weight of the plate on the pointil of the short lever arm. The pin 52 supports also in a free-‘ rocking manner a spider with amis 51, `58 and 59. (Said spider is shown in the drawing infront of the lever.) An oñset-finger 56 of the short lever arm projects over the top of arm 51 and causes. the latter to be turned downward when the weight ` 6 and. is, therefore, the'preferred means to _serve as an essential part of the construction of the 1fìllirying apparatus according to the present inven on. » - When the apparatus is put in operation and the electric current is beginning to flow through the resistance wire in the plate and heating element 4 I , the bimetallic strip 39 -will curl upward, thereby , pushing the steel ball 45 on top of rod 43 against one wing of the upper door 9 and causing the lat ter to be opened gradually. The heating element 4I is used for the purpose to cause the upper door 9 to be opened more promptly than would be the case if the bimetallic strip 39 received only the of plate 20 increases due to moisture adsorption. 15 heat supplied through radiation from plate 20, In consequence of this the small horse-shoe mag net 36 attached> to the arm 58 of the spider will approach the mercury switch 31, secured to brack et 53, until the magnetic attraction of the soft . this radiation beingy very small at ñrst. When door 8 has opened slightly the mechanism already » previously described comes into play which causes the lower door 1 to fall shut suddenly. Soon iron armature inside the switch 31 is sufficiently 20 afterward watervapor will be evolved from the strong to seize and hold the magnet. The heat plate ln increasing volume as the plate gets hot radiated from the underside of the plate 20 upon ter. However the heat required for the evapora the bimetallic strip 34 causes the latter to curve 'tion’of the water tends to check a rapid rise of downward until it touches the setscrew on the temperature of the plate until most of the water arm 58 and `turns lthe spider backward so that 25 has evaporated when the temperature rises rap the magnet 36 becomes detached from the switch idly until finally the heat radiation upon the bi 31 which interrupts the electric current. At this metallic strip 34 underneath the plate 20 becomes Y juncture the lever as well as the spider are again strong enough to deflect the strip 34 downward at their original position. v to a sufficient degree to withdraw the magnet The drawings Fig. 10 and Fig. l1 illustrate a 30 36 from the switch 31. During the desorbing ' third embodiment of the present invention. Four phase which for a small-sized model ofthe ap vertically suspended adsorbent plates> 20a, 20h, paratus generally lasts ten to fifteen minutes, the 20c and' 20d, spacially separated, are rigidly water vapor is rapidly carried. away by air convec linked together in any suitable manner, as for tion currents rising from the hot plate. The example by means of rods 60 and porcelain spac 35 moist warm air travels upward along the under ers 6l. The projecting ends of the rods 60 are engaged by links 62 andby means Aof these se cured to a U-shaped frame 63 pivoted in a free swinging manneron the, two pins 64. On the opposite side of the frame a rod 65 with attach ment 66 is usedfto support the middle part of thel frameì by the intermediary of a helical spring on the pivots of two bell-crank levers ¿1 -The heli~ cal spring consists of the two parts' 61 and 68. By turning a knurleddisc 69 on the outside of container I and therefore` also by turning the threaded shaft 1| in one direction or other, ’the two springs 61'and 68 can be tightened or re-' laxed at will without disturbing the position of attachment 66 and other parts of the control mechanism. ' When thus- making the sensitivity to defor mation of the helical spring adjustable by chang ing its stiffness (i. e. the tension under which it operates) it- is obvious that a given weight incre mentl acquired by the plate system 20a, 23h, 20c and 20d'as a result of >water adsorption, can be caused to either-advance or- retardthe closing of theelectric circuit and> hence the> onset of' the adsorbing phase. > Rod 65 is steadied in its upright position by be ing `linked at its lower end by a pin'12 to a lever 13 capable of swinging on pin 14 which is firmly >secured to a bracket `15. A sleeve 16 on pin 12 projects over the top of the arm 51 of a spider piv oted on the pin 14. The -arm 59 of the spider carries a setscrew facing the bimetallic strip 34 and the arm 58 supports a small horse-shoe mag net 36 actuating the switch 31 mountedon the bracket 15. side of the partiallyopened door. » The action of ' air as a 'diluent prevents the water vapor from condensing on the cold walls and other surfaces of the upper compartment. An effective air circu lation is set up by the' influx of cold air over the top of the downwardly inclined wing of door 9 _into the interior. The inflow and outflow of the air is therefore in counter-current motion, and as a `result’of the rapidwithdrawal of heat by the 45 eliluent‘ vapor mixture the drying chamber 3 re mains cool and the‘walls of the upper compart ment 4 become only slightly warm. When'the electric current- is automatically in terrupted by the removal of the small horse-shoe 50 magnet from the Mercoid switch 31 the-air cir culation is maintained for some time longer, while the plate 20 is cooling. Because of the fact that the return of the door 9 to its closed position pro cee'ds -in thermostatic relationship with Vthe rate 55 of cooling of the plate 20, obviously the door 9 vcan never be in its “closed” position so long as the plate »is still warm. This is important inasmuch as this circumstance insures that the plate 20 recovers its adsorptive potency as rapidly as pos 60 sible. The same conditions prevail when a plu rality of plates is employed, 'as shown ‘in Fig. 1l, instead Alternatively of a single it isplate. not necessary that the en 'tire number of plates be used together in the 5 balancing mechanism. Instead, only one plate, but of the same size as the others may function as a pilot plate for closing and opening the elec tric circuit while the other plates are mounted ' stationary and connected in series to the pilot 70 plate. This arrangement will simplify the con Needless to say a. flat coil spring could also be ' struction and provide a better utilization of the used to operatefundera tension, varied at will for space in plate compartment 4. purposes of regulating the performance of the The adsorbent plate 20 of the upper compart-4 apparatus. However the previously described use ment> 4 never requires to be reconditioned in or‘ of the double helicalspring simplifies the design> 75 dinary service -since any volatile substance be 2,411,039 . 7 . genized by passing through a shredder. In both >i'cles water which may condense on its surface will Llways be expelled from the plate during its re tctivation in the desorbing phase. This is borne )ut from trials with a model of the non-auto natic type extending over several years when the )lates had lost none of their initial drying power md capacity. -compositions the asbestos used Was a good grade of chrysolyte, size “5M20.”. The field of application for the drying appa ratus determines the choice of the desiccating agent to.be used. Generally silica gel has a broader range of adsorptivity, but a smaller dry' ing intensity than Activated Alumina. The lat - To be suitable for use in the present drying ter also has theadvantage of being effective at ipparatus, the adsorbent plate must be highly ‘ -aorous in texture so as to enable the water vapor 10 somewhat higher temperature, as for example in tropical countries. In certain applications where :o readily penetrate to the interior of the plate. [t also must be mechanically strong and durable and not develop cracks duringthe rapid removal if the water vapor in the heating operation. The a particularly intense drying or desiccating ac tion is required the use of soluble anhydride also comes into consideration, notwithstanding its comparatively high specific gravity and narrow -»articles composing the platev must be ñrmly range of effectiveness. In this case the drying action is due to a chemical binding of the water aonded together to prevent any loss of material in continued operation and to make it possible ;o use the plate without any protective covering. F‘inally the plate should have a high capacity to form the hemi-hydrate of calcium. sulfate, whereas in the case of the desiccants mentioned previously the water is held by capillary con as well as a high intensity for adsorbing water vapor. These various requirements are fulñlled densation‘in the'pores of these substances by molding the plate Vfrom a three-component What is claimed as new and useful is: _ ' 1. A drying'apparatus comprising the combina mixture comprising a desiccating agent, a fibrous tion of a drying chamber adapted to receive ma filler and a binding agent. In order to be Aable to use a larger proportion of the desiccating 25 terials to be dried and an adsorbing chamber, said chambers having a common wall,.a movable door agent in the mixture than has been possible by in the wall, a moisture adsorbing unit'and a. using gypsum as a binding agent according to heating element therefor within the adsorbing chamber, means for movably supporting said ad was extraordinarily suitable as a binding agent. 30 sorbing unit, and means actuated by said sup U. S. Patent 2,067,920, further experimentation led to the discovery that the mineral bentonite porting means when a predetermined weight of moisture has been adsorbed by said unit ‘to en Not only was it found possible to use this binder in appreciably smaller quantity, but its use in ergize said heating element, a second door sep the composition greatlyv facilitated the kneading arating the adsorbing chamber from the _outer and molding of the moist mixture into a homo geneous, plastic mass from which surplus water 35 atmosphere to permit vapors liberated from the adsorbing unit, upon application ofheat thereto could be easily removed by compression in a spe to escape into the outer atmosphere, thermostatic cially designedv mold between liners of cloth or means to open said second door and `simultane the like, and applying' the pressure gradually ously effect the closing of the door between the with increased force. The good plasticity of the chambers, said thermostatic means being heated mass also made it possible to impress in it with simultaneously with the energizing of the heat out any effort a previously wound and evenly ing element, and means for de-energizing said spaced resistance wire coil into one half of the heating element when a desired weight of water plate before adding theremainder of the mass has been removed Áfrom the adsorbing unit. in such a manner as _to preclude formation of 2. A drying apparatus comprising the combina air pockets and ñnally expressing the surplus water from the composite slab in the mold. On tion of a drying chamber adapted to receive ma terials to be dried and an adsorbing chamber, A said chambers having a common wall, a. movable door in the wall, a moisture adsorbing unit with a manufacturing scale it would probably be most , advantageous to produce the plates in half thicknesses by extrusion. No claim is made, how ever, for any particular method in producing the 50 in the adsorbing chamber comprising a plurality of spaced moisture-adsorbing plates having elec molded plates with embedded resistance wires. trical resistance wires forming heating means For experimental purposes plates of corru embedded therein, means for movably supporting gated cross-section were made with the over-all said adsorbing unit, and means actuated by said dimensions 6” x 3” x 1". the thinnest part of the plate between the Íurrows being 1/2”. They 55 supporting means when a predetermined weight of moisture has been adsorbed by said unit to en contained embedded Nichrome resistance wire ergize said resistance wires, a second door sep coils wound on a 332" mandril, 16 ft. of 30 B. & S. arating the adsorbing chamber from the outer ga. “Chromel A” wire being used for operating atmosphere, located approximately over the ad- ' on 110 volt. Satisfactory’plates could be made ïrom commercial silica gel as well as Activated 66 sorbing unit whereby vapors liberated from the adsorbing unit, upon application of 4heat thereto, esscape by convection into the outer atmosphere, Alumina. Typical -mixtures were as follows: ., Parts thermostatic means to open said second door and (A) Silica gel--___'-__- __________________ __ 57 Asbestos _____________ _-.________ _;_____ (B) 29 simultaneously effect the closing of the door be 65 tween the chambers, said thermostatic means Bentonite ___________________________ __ 14 comprising a bimetallic strip having an independ Activated Alumina ___________ _; _____ __ 'l0 ent heating element in association therewith and being energized simultaneously with the' energiz ing of the resistance wires of the adsorbing unit Asbestos ____________________________ __ 20 Bentonite____._-_l ______________ _..-..___ 10 „ The silica gel used was of m1nus\ 100 mesh 70 and means for de-energizing said resistance w-ires when a desired weight of water has been removed particle size. The Activated Alumina was a minus from the adsorbing unit. 300 mesh powder. Each of the above mixtures 3. A drying apparatus comprising the combina was triturated and kneaded to a stiff dough with tion of a. drying chamber, adapted to receive ma approximately 50 parts of water per 100 parts of the dry mixtures. The dough was'then4 homo 75 terials to be dried, an adsorbing chamber in close 2,411,039 « . proximity thereto and in communication there with, a movable door between the said'cham ' bers, a -movably supported moisture-adsorbing unit, a counterbalancing means comprising an 10 - . . tion of a drying chamber to receive materials to be dried, an adsorbing chamber in close proximity thereto, a moisture adsorbing unit in'said ad sorbing chamber with heating means, a, movable door between the drying chamber and the ad lsorbing chamber, a second door separating the adjustable spring adapted to hold said adsorb ing unit in .aA predetermined position when freed -from moisture yet allow said unit to move down adsorbing chamber from the outer atmosphere, means adapted to >instantaneously close the said ward as it adsorbs moisture, the spring being first door upon the incipient opening of the sec adapted to restore the moisture adsorbing unit to the position occupied by it before adsorption of 10 ond door thereby permitting vapors liberated from the adsorbing unit to escape into the outer water when adsorbed water is removed, heating atmosphere, said second door being intercon meals for said moisture adsorbing unit, means to energize said heating means actuated by the nected with the first door through the. instru counterbalancing means upon the downward mentality of a link supporting a pawl provided movement of the _moisture adsorbing unit after 15 with a finger adapted to release a latch attached adsorbing a desired amount of water, means to to the ñrst door from the said pawl engaging it when the finger of said pawl is seized during its close the door between the adsorbing chamber and the drying chamber and simultaneously open downward travel by a. swinging hook pivoted on the side of the adsorbing chamber, a, bi-metallic from the outer atmosphere whereby the vapors 20 strip having an independent heating element in liberated from the adsorbing unit, on application association therewith, being energized simulta of heat thereto, can escape into the outer atmos neously with the energizing of the heating means phere by convection, said door-operative means for said .adsorbing unit, a link connecting thek bi comprising a bimetallic strip having independent metallic strip and said second door whereby said heating means energized simultaneously with the 25 door is Lopened when the «bimetallic strip is bent heating means for the heating means of said upon being heated and means for de-energizing adsorbing unit and means to .de-energize both said heating means when a desired amount of heating means when a desired amountrof water moisture has been removed from said moisture has been removed from said adsorbing unit. adsorbing unit. ~ ' a second door separating the adsorbing chamber 4. A drying apparatus comprising the combina 30 - RALPH V. HEUSER.