US2648206A

US2648206A - Method and apparatus for cooling aggregates

Info

Publication number: US2648206A
Application number: US149111A
Authority: US
Inventors: Clifford H Carr
Original assignee: J SPARKS VAN
Current assignee: J SPARKS VAN
Priority date: 1950-03-11
Filing date: 1950-03-11
Publication date: 1953-08-11
Anticipated expiration: 1970-08-11

Description

Aug. 11, 1953Y c. H. CARR METHOD AND APPARATUS FOR COOLING AGGREGATEIS 3 Sheets-Sheet l Filed March 1l. 1950 l v, r

li EMM@ Zhwentor 6,. .A WH

a f MN.

Clttomegs C. H. CARR METHOD AND APPARATUS FOR COOLING AGGREGATES Aug. 1l, 1953 3 Sheets-Sheet 2 Filed March ll. 1950 (Ittomegs Aug. l1, 1953 c. H. CARR 2,648,206

METHOD AND APPARATUS FOR COOLING AGGREGATES Filed March 11, 1950 3 Sheets-Sheet 5 :inventor .g5 W1-@fd zw y Gttornegs Patented Alug. 141.,

METHOD AND APPARATUS FOR COOLING AGGREGATES Cliord H. Carr, Kansas City, IMo.,-assigncr of one-half yto Van J. Sparks, Kansas City,I M0;

Application March 1'1, 1950, 'Serial N o; 149,111

16 Claims..-

This invention relates to a method of and' apparatus for conditioning and/or cooling-material consisting of large masses of individual particles such as aggregate and/or other ingredients of a concrete mix, prior to mixing.

It is common practice in large concrete construction projects to erect concrete mixing plants which include towers having bins adjacent the upper end thereof for receiving ingredients such as aggregates, sand and cement of the concrete mix. Below the bins are weighing devices which receive the ingredients from the bins, said weighing devices weighing and proportioning the particular ingredients and then delivering same to mixers arranged in the tower below the weighing devices and adapted for delivering mixed concrete to trucks for movement to a place of use. In such projects large quantities of aggregates and/or other ingredients must be available and said ingredients are commonly exposed to the climatic conditions so that the temperatures of same vary widely under normal operating conditions making it diiiicult to maintain uniform temperatures of the concrete mix.

It is desirable particularly in large concrete construction projects, such as large dams and the like to pour the concrete mix at a temperature which is above freezing and at the same time low enough that the heat generated by the setting process will not increase the concrete above 100 F. as at or about 125 F. concrete becomes like gelatin and will never set. The specifications on present dam contracts require the concrete mix tc be controlled to a maximum of 65 F. and it is recognized it would be preferable to reduce the requirement to between 50 and 55 F. but until now such low pouring temperatures have not been obtainable under all climatic conditions mix with ice or inundation of the aggregate have been found objectionable. Only a limited quantity of ice can be used due to the small amount of water speciiied in the concrete mix and such a limited quantity of ice is incapable of producing the desired low temperature of the mix. Methods of cooling by inundation vcomplicate the control of moisture, require special tanks for the aggregate in addition to the mixing tower bins, making the handling of the aggregate dinicult and there is loss in cooling effect due to reheating in the time lapse between cooling and mixing of the aggregate. Current methods using delivery of cold air from a central refrigeration and air cooling plant working on removal of sensible heat to the lower portion of a plurality Current methods of cooling concrete of aggregate bins in a mixing plant are objectionable due to necessary shut down time for defrosting'or maintenance of the refrigeration plant and limitation of range of cooling due to the verylarge amount! of air that must be forced through the aggregate because of small heat carrying 'capacity oi air when operating on sensible heat change. Also such operations requiringa highrise of temperature of the air lower the required low temperature limit which causes frosting of the refrigerantcoils.

The' objects of the invention are to provide a method andapparatus for conditioning and/or cooling material which overcomes the noted disadvantagesand-objections of other methods; to provide a method of conditioning material in a plurality' of bins wherebyl the material' in and moving through therespective bins is conditioned and/orcooledf independently of the other bins; to render the various operations involved with the conditioning and/or cooling of material as' nearly continuous as' possible; to provide apparatusfor conditioning aggregate or the klike by controlled movement of uids through they aggregate whil'e in a bin of a mixing tower; to provide conditioned air delivery mechanism and ducts so arranged-toincrease the initial surface of material exposed tothe' delivery of air and reduce the static head-resisting movement of air through the aggregate; to provide a central'refrigerating systemy locatedv adjacent to the laggregate mixing plant and connected to the various aggregate bins by means of chilled water, brine,v or uid or refrigerant' lines in such a manner that any portion of the central plant can be concentrated onv any partfor al1' of the bins that require cooling 'ata given time', the plant being proportioned in such 'a way that'it has sufiicient capacity'without having to work at low enough temperatures to vcause 4'the coils to frostk up and'thereby lose capacityandy require defrosting; to provide apparatus for cooling aggregate andthe like in deep beds in bins by selectively delivering large volumesof cooling uids to the upperlevels of the bed'and smaller volumes of rcooling fluids at lower levels whereby most of the cooling is donein the upper portion of the bed with lower static head and power for movement of the iiuid through thebed'of material to progressively cool thelagg'r'egate andthe like as it passes down-'J wardlythrough the bin;r to provide for applyingwater to the4k aggregate at the top of the bin,

the quantity'of the water being approximately' that `whiclrw'ill be evaporatedby theheat in the'aggregate in latent' cooling resultingl from"` delivery of cooled dry air to the aggregate at lower points in the bin; to provide for cooling the aggregate and the like in a plurality of bins by delivering two uids to the bins for countercurrent ow through the aggregate and selectively controlling the now of said uids whereby they cooperate to effect evaporation cooling and removal of heat from the aggregate so the temperature and moisture content of the aggregate delivered from the bins are maintained; to provide for cooling of aggregate by selectively delivering liquid and air hereto and selectively recirculating all or a part of said air` and liquid, said air and liquid being selectively cooled by a suitable refrigerating system whereby the temperature of the aggregate and water content thereof may be accurately controlled as desired; to provide individual air cooling and delivery and/or circulating mechanism for each bin to be cooled, the air being delivered in a plurality of stages to selected points in the bin for stage cooling of the aggregates and the like; and to provide a method and apparatus for cooling material such as aggregates and the like in bins of conventional concrete mixing towers, said apparatus being compact in construction and arranged to provide a continuous cooling of the material moving through the indvidua1 bins for maintaining selective individual delivery temperature and moisture content of the material, the material being cooled in stages whereby a maximum of cooling can be obtained efiiciently with small power output, the cooling operation being flexible to meet varied conditions and specications in the pouring of large masses of concrete.

In accomplishing these and other objects of the present invention, I have provided improved details of structure, the preferred forms of which are illustrated inthe accompanying drawings, wherein:

Fig. 1 is an elevation of a concrete mixing tower having apparatus thereon for conditioning the material in the bins.

Fig. 2 is a vertical sectional view through concrete ingredient containing bins in the upper portion of the concrete mixing tower taken on the line 2-2, Fig. 3, said structure being arranged for multiple stage cooling and conditioning of said ingredients.

Fig. 3 is a plan View of a concrete mixing tower having aggregate cooling apparatus in accordance with the present invention, a refrigeration plant being shown diagrammatically in connection with the tower.

Fig. 4 is a partial vertical sectional view through a bin in a concrete mixing tower with a modified form of aggregate conditioning mechanism.

Fig. 5 is a partial sectional view through a bin of a concrete mixing tower, with a further modified form of conditioning mechanism.

Fig. 6 is a sectional view on the line 6 6, Fig. 5, illustrating a grizzly in the bin for the drainage of liquid from the concrete ingredients in said bin.

Referring more in detail to the drawings:

I designates a concrete mixing plant which consists of a tower 2 constructed of structural steel or the like and arranged to support a plurality of hoppers or bins in the upper portion thereof. It is preferable that the bins be so arranged that a central bin 3 serves as a reservoir for cement 4 and other bins 5 arranged around the bin 3 serving to contain gravel, crushed stone or other aggregate 6 and sand 1, the number of bins holding the respective materials being approximately in proportion to the relative quantity of the respective materials used in the concrete mix. The bins are so constructed as to provide a deep bed of material or ingredients of the concrete mix contained therein. The cement bin 3 has downwardly converging bottoms 8 terminating in spouts 9 having gates I0 thereon to control the iiow of cement from the bin 3. Each of the bins 5 has inwardly sloping bottoms II terminating in spouts I2 having gates I3 for control of the flow of the cement ingredient contained in the respective bins. Arranged in the tower below the bins in a position to receive the concrete ingredients from the bin spouts are weighing devices I4 for measuring and proportioning the concrete ingredients and selectively delivering same to concrete mixers I5 arranged in the tower below the weighing devices. The weighing devices I4 and mixers I5 may be of any conventional construction and are preferably arranged in the tower for gravity iiow of the ingredients from the bins to the weighing devices and then to the mixers, and from the mixers to suitable means, such as trucks, for conveying the concrete to a place of use, such as a dam site.

ln the bin structure illustrated, the cement bin 3 is formed by side walls I6 extending upwardly from the bottom 8, said side walls preferably being arranged in a polygonal shape and forming inner walls of the bins 5. Outer side walls iT extend upwardly from the bottoms i in spaced relation to the walls i6 and partitions I8 divide the space between the walls I6 and I'I into a plurality of bins 5. A cover I9 preferably converges npwardly from the upper ends of the side walls i? and has engagement with the walls I6 to enclose the respective bins. Rotatively mounted at the apex of the cover I9 is a hopper 23 for receiving the various concrete ingredients, said hopper being provided with a spout 2! so arranged that the hopper may be rotated to position the spout 2I for selective discharge through chutes 22 to the respective bins 5 cr may be positioned between the chutes for the discharge of cement into the bin 3. With this arrangement the Various ingredients of the concrete mix may be delivered to the hopper 2G of the tower I and selectively discharge into the bins at intervals to maintain the levels of the ingredients in the respective bins between selected maximum and minimum heights.

Cooling apparatus 23 is provided for each of the bins containing aggregate, sand or the like. rThe cooling apparatus 23 for each bin includes a coil 24 preferably arranged horizontally and fixed in a housing 25 having side and top walls 25 and 21 and an opening 23 in the bottom, the housing and coil being supported by suitable members 29 on the tower structure and preferably arranged adjacent a decking 30 extending around the tower for movement of persons inspecting and maintaining the equipment. Each of the coils is preferably connected with cooling fluid supply and return manifolds 3I and 32 respectively for chilling said coils, suitable valves 33 being arranged for individual control of the fluid delivered to the respective coils. The manifolds 3l and 32 are connected by suitable pipes 3f. and 35 respectively to suitable refrigeration apparatus in a refrigeration plant 36.

The plant 3B includes a plurality of refrigerant compressors 3l, a condenser 33 and evaporator coils in a heat exchanger 39, whereby water may be circulated by a pump 40 through the heat exchanger in contact Vwith .the `evaporator coils and the chilled water pumped through .the manifold 3l for supplying the respective coils with chilled water. In normal 'operations it is preferred to use chilled fluid in the coils v24 in order to eliminate any frosting condition. However, if desired, the refrigerant compressed by the compressors 3l may bedelivered direct to the manifolds Si for supplying the coils A24 so 'said coils will serve as the evaporator coils of the refrigeration system. If refrigerant is circulated through the coils 24, suitable controls will be used to maintain the coil operation above the temperature at which frosting occurs.

The material in each of the bins is-cooled 'substantially in the same manner, with individual controls in the cooling equipment for regulating the cooling and/or conditioning of the material in the respective bins, whereby the equipment will properly function to cool aggregate, sand and the like having different particle sizes and different static head for air circulation through the material in the bins. A fan 4I capable of delivering a relatively large volume of air at low static head is suitably mounted on the towel' and has its intake communicating by means of a duct 42 with the interior of the respective coil housing whereby the fan draws air through the opening 28 in the housing over the coils and through the duct 42. The air is discharged by the fan 4l through a duct 43 extending into the respective bin 5 and terminating in a downwardly directed frustroconical outlet 44 located below the minimum level of material in the bin. The outlet 4d, being directed downwardly in the material, acts as an outlet of a Venturi tube and serves to convert the velocity energy of the air into static head as required for maintaining movement of air through the material to be cooled. Also the material whether ne or coarse will move outwardly and downwardly along the wall 45 of the outlet member and then slip downwardly past the edge of the wall andinwardly whereby the material itself forms an inverted cone-shaped space 46 below the outlet 44, thereby providing a considerably greater area of material surface exposed to the air delivered by the duct 4S. This large area of initial surface of the material exposed to the air from the duct 43 reduces the initial static loss of starting ow of air through the material. The walls 45 of the outlet 44 may be perforated to form openings 47 which are smaller' than the size of the aggregate being handled in the respective bin so that no material will pass through said-openings but air may pass throughthe openingsiinto material thereby further increasing the surface of the material exposed to the cool air delivered by the fan 4l. As illustrated in Fig. 2 the outlet member 44 is located relative to the sides of the bin 5 and the normal slope of the upper surface of the material in the bin to substantially equalize the movement of the air from theoutlet member through the material completely around the outlet member and thereby avoid any stratification or channeling through the material.

A second fan 48 preferably operating at higher static head and lower volume than the fan 4| is suitably supported in the tower adjacent the coil housing 25 and has its inlet connected by a duct 49 with said housing to `also draw air over the coils 24, said fan 48 discharging the air through a duct 50 extending into the binf5 and terminating in ya downwardly turned "frustrwl conical outlet member 5| centrally located lin the material in the bin adjacent the spout I2. 'The material moves downwardly over the wall of the outlet member 5| and also converges inwardly to form an inverted cone-shaped space 52 below the outlet member, the wall 53 of said outlet member preferably having openings 54 therein for discharge of `air into the material in thesame manner as the air is discharged from fthe outlet member 44. Dampers 55 and 56 are located in the ducts 42 and 49 respectively for aid in controlling relative movement of air bythe fans 4I and 48, and also permitting either of the fans to operate singularly for discharging air into the material'in the bin 5 for cooling same, particularly where the reduction in temperature required is relatively small.

Stacks 51 are arrangedon the cover 19 above each of the bins 5 for escape of air and'moisture from the bin to the atmosphere, said stacks preferably having dampers 58 for selective control of the area of the opening in the stack for the passage of air therethrough. Any suitable means may be applied to the ends of the stacks for .preventing rain and the like from entering the bins through said stack.

A plurality of spray pipes 59` are arranged in each bin 5 adjacent the cover I9 for substantially uniformly spraying water over the upper surface of the material contained in the bin. The 'spray pipes 59 preferably have communication Awith 1a manifold 60 which is connectedby a pipe 6| vwith the manifold 62 suitably arranged on thetower' and having connection with the spray pipes inthe various bins 5, a valve 63 preferably being arranged in each of the pipes 6I for individual vcontrol of the quantity of water sprayed inthe respective bin. The manifold 62 is supplied with water under pressure by a pipe 64 leading to a suitable source of Water supply and said water may be chilled in the refrigeration plant if desired. It is preferable that the quantity of water sprayed on the material in the bins be such that the air delivered to the material in the bins by the fans 4l and 48 will evaporate substantially all of the water from the material Wherebysaid material is substantially dry when discharged from the spouts l2, the evaporation of said water cooling the material. An automatic control for the valve 63 may be arranged by providing a differential wet and dry bulb instrument 65 arranged in or adjacent each of the stacks'of the bins 5 and connected with the valves -63 rto cut` off the supply of water sprayed on the material when the differential approaches a selected `minimum and to open the valves to provide `additional spray when the differential approaches a maximum. If the material is too dry the sensible heat Will increase the differential and turn kon more water.

The operation of the apparatus illustrated in Figs. 2 and 3 in practicing the method for cooling of material is such that the quantities of water and air delivered to the bins and the relative proportions of same may be regulated to provide eicient cooling of the material and regulation of moisture content to a desired amount regardless of outside atmospheric conditions. The material is delivered to the hopper 20 and directed by the spout 2|`through a selected chute 22 into a bin 5 until the bin is lled above a minimum height which must be above the outlet member 44. The refrigerating plant 36 is operated .to provide desired coolant in the coils 24-whichare preferably operated in such a manner that the temperature thereof is just above the frost point. To assure such operation the compressors preferably move refrigerant through the heat exchanger 39 for chilling water, brine or the like liquid to a temperature slightly above the freezing point of the liquid. The liquid is pumped through the manifold 3| and selectively admitted to the respective coils 24 by adjustment of valves 33. Water which may be chilled if desired is delivered through the pipe 64 to the manifold 62 and supplied onto the surface of the material in the bins 5, wetting said material and also additional material which is delivered to the bins to maintain the level above a minimum therein and replace the material removed through the spout I2. The fans 4I and 48 are operated to draw air through the openings 28 around the coils 24 chilling and also condensing moisture from the air whereby relatively dry cold air is moved by the fans 4| and 48 and delivered to the material through the outlet members 44 and 5l. The air delivered by the fan 4l, being of relatively high volume and low static head, tends to evaporate the water on or in said material to cool same by evaporation and the latent heat isV carried away in the air. The large quantity of air delivered by fan 4l removes most of the moisture whereby the air delivered by the fan 48 is capable of substantially drying or evaporating the moisture in the material passing thereby to the spout l2 and further cools the material to reduce the temperature thereof to approximately F.

If the material delivered to the bin 5 is relatively wet as when there has been rain on a storage pile exposed to the atmosphere, less water will be delivered by the spray pipes o9. When less reduction in the temperature of the material is required, as when the atmosphere is cool, it is possible to provide the cooling by air from only one fan or the proportions of air delivered by the fans 4I and 46 may be adjusted by the dampers and 56 for most eiflcient cooling. In extreme cold temperatures heated liquid may be passed through the coils 24 for heating the air delivered to the material and thereby maintain the temperature subtantially as desired. Obviously the entire equipment is such that each portion and each bin may be adjusted and regulated to meet substantially any requirements imposed by climatic conditions and still maintain the temperature of the materials delivered through the spouts l2 whereby the final mix will be according to the specifications required on the construction project. The cooling of the material is effected continuously while the material is fed to and drawn from the bins and in effect the cooling is on the principle of counterflow as the material and water move downwardly through the bins the air moves upwardly through the material, the cooled air becoming warmer and increases in moisture content as it moves upwardly through warmer and wetter material and the air total heat content exceeds that normally exhausting in outdoor air and air is exhausted from the system, all of the apparatus being arranged to accomplish a maximum in efliciency in cooling of the material with a minimum of power. To further illustrate the operating conditions of the apparatus the following is an example of the operating characteristics, temperatures and air flow at selected material and climatic temperatures in the operation of a concrete plant having a capacity of 175 cubic yards per hour. Assuming that the aggregate is delivered to the six material bins 5 illustrated at a temperature of 100 F. and said aggregate cooled and delivered through the spouts I2 at a temperature of 45 F. there would be required approximately 672 tons of refrigeration, or in other words the cooling of the material in the bin would be at an average rate of 112 tons of refrigeration to each bin per hour to remove 8,064,000 B. t. u. per hour. Water or other suitable liquid is chilled in the refrigeration plant and circulated through the coils 24 at a supply temperature of approximately 34 F. Assuming the outside air drawn over the coils by the fans 4I and 48 is 100 F. dry bulb, 72 F. wet bulb, and 35.8 total heat and the chilled liquid circulated through the coils 24 sufficiently to reduce the air to a temperature of 40 F. dry bulb, 39 F. wet bulb and 14.6 total heat, 12.7 cubic feet per pound of air, the air will move upwardly through the aggregate, cooling and evaporating the liquid on same. To cool the aggregate by combined latent and sensible heat methods, the fans are operated to move sufficient air through the aggregate whereby the air exhausted through the stack at the top of the bins has a temperature of 92 F. dry bulb, F. wet bulb and 55.18 total heat per pound, that is, the total heat content of the air is increased 41.2 B. t. u. per pound which heat is absorbed from the aggregate. The air moved through the aggregate under these conditions is determined as follows:

112. axane B. t. a/um 6900 cu. ft./min.

If all of the heat of the aggregate were removed by evaporation in the form of vapor the water evaporated would equal 70=820 pounds per hour of water The per cent of heat removed by a sensible heat is approximately 25 per cent. Therefore, 3,820 25% equals 2,080 pounds of water. 8,320 less 2,080 equals 6,240 pounds of water, which is added for evaporative cooling. Batch water usually required for concrete mix amounts to pounds per cubic yard and for 175 cubic yards per hour would require 17,500 pounds of water per hour, so the amount of water added for evaporative cooling even if only partly removed would not leave the aggregate too wet.

It is customary in concrete mixing towers for the depth of the material in the bins to be more than 17 feet. In the present structure it is contemplated that the average depth of the material from the lower air outlet be approximately 17 feet and that the air from the upper outlet be forced upwardly only through approximately 4 feet of material whereby less static head is required and also less horsepower to drive the fans than would be necessary if all o the air were forced through the total height of the bins. For moving 6,900 cubic feet of air per minute in each ofthe bins, that is a total o 41,400 cubic feet per minute through the entire six bins of aggregate :requires approximately horsepower. The tons of refrigeration used equal 9.? exhaustedcontaininga181-Bi t. u'. 57.5"'1; R. for eaclipoff-six binsequals345.horsepower refrigeration; loadvr plus 120fy horsepower." fan load' equals total aofzi465 liorsepowerforfthe yentire `cooling of 175;'cubiciyards Vperhourfrom 100p- F; to 45 F.

Iirstheiv form of the-invention illustrated in Fig; 4,;chilledfwater orrefrigerant isy delivered to amam'fold llllfhaving branches 61 connected with coils 58;'y vsuitably mounted.: in housings. 69*y each of; which has' communication with the upper endziofza bin fthroughs-the cover I9. The return fromtthercoil :is/"connected to a manifold Iifor thefreturn of liquid tothe refrigeration plant. A fanv 1| isarranged adjacent to the housing'69and-"has communication with the interior-` thereof abovel the.` coil 68.11 whereby;` air is drawn fromtlfievhousingY andi-forced by the fan 1I through a duct 12 which extends into the respective bin 5 and terminates in a downwardly turned outlet member 13 constructed substantially the same as the outlet members 44; suitable dampers 14 being provided in the duct 12 for controlling the opening therein. A fan 15 capable of moving air at high static head has itsv inletl connected by a duct 16 with the housing 69 fory communication therewith above the coil 68 whereby air is drawn from the housing to the fan and rdelivered through a duct 11 which extends into the bin 5 and terminates in a downwardly directed outlet member 18 constructherethrough. Communicating with the housing 69 is a stack 8D opening to the atmosphere, said stack having adamper 8| for control of the opening through the stack Yand thereby controlling make-up air delivered to the housing 69. Also a damper 8| is arranged in the housing 69 for controlling iiow of air over the coils 68 whereby all orv any part of the air moved by the fan 15 may be drawn through the stack 80 from outside if desired.

In this form of the `invention water, chilled if desired, is supplied to a manifold 62 Afor delivery through the valve controlled lines 6| to the spray pipes 59 located in the bin adjacent the cover I9. Also connected to the manifold 82 isa pipe 32 having a valve 83`therein controlling ow of water through the line, said pipe 82 being connected with spray pipes 84 located in the housing 69 above the coil 68. With this arrangement of the structure the material is delivered to the tower and through the chute 22 to the bin 5 to replace material drawn from the bin through the spout I2 and maintain the level of the material between a minimum and a maximum height in the bin. Chilled Water or coolingA media is supplied to the coil 68 and the fans 1| and 15 operated to draw air from the bin 5 over the coil 68 from the housing 69 and deliver same to the binby way of the

outlet members

13 and 18, which air moves upwardly through the material cooling same and to the upper portion of the bin where said air is again drawn over the. coil 68 thereby providing recirculation of the air used for cooling the material. Damper 8| is adjustedto selectively add mal-zeup air to the recirculated air to replace air lost inthe apparatus anda-lso to replace air that is allowed to escape through a stack 85 havinga damper 85 therein. The control of the dampers 8| and 86 regulates the amount of `air thatA is `recirculated proportion. to make-up air?. drawn ffrom fthe atmosphere-'and aid in conf trollingithemoisture content of' said air.

Water is sprayed Vfromthe spray pipes 84-fover the coils` (iB-'removingl dirt and anyfrost therefrom, thereby: keeping saidcoil clean for great est heat transfer. coil' may be dropped onto eliminators or the like for `removalfor dropped onto the rmaterial in the biniff desired.y Also watery is sprayed from the' spray pipes 59r`fory wetting of the material in thefrbin 5, said water being regulated to substantiallyfthe.*quantityfwhich kthe air applied bythe fans==1|'and-15 will'evaporate in the cooling `of the material to maintain substantially dry ma;- terial=at the-spout: I2. The delivery of air by thecfians 1| and y15 may be individually regulated.

Thetemperaturel off the cooling media` in theJ coils -68f'forthe respective bin',v the da-mpers 8|? and 86,5 and vwater supplied "byithe sprays 59 and* fillK4 are vregulated 4toprovide rthe desired temperature; content of thermaterial delivered `fronrthe.

bin. The use of aseparate unit for each-bin:`

permit'sfthe portions of said units to be adjusteditor accommodatefthecooling of materials of. various sizes, thereby efficiently cooling the ma-V terialwhetherit'be sand, aggregatefor relatively-v coarse stone. v

' Inl the formy `of 'the invention illustrated.in1igs..

Bandi-67 the' bins 5 :have ai spout I2; inner wall,

slide overr the topf of the grizzly toward thery spout I2 while water orother-liquiddrainsbe.-- tween the. grizzly-members. The rbin isprovided with a sump 88 located below the grizzly and" preferably'y so constructed for access. to the-sump forcleaningl dust; dirt* and thel like therefrom. Communicatingffwith the sump is a drain pipe` 89 which" leads to areservoirl 90 through which the liquidilowsover a-.pluralityof bailles to.-fur-- ther settle outany. dirt and the like therefrom; the reservoirA being. provided'v with y manholes or thelike providing accessA for cleaning of the reservoir. Connected. with the reservoir` is`r` a valve-controlled pipe 9| for `selectively adding make-up liquid tothe system to replaceany` liquid.v lost therein. Liquid'is drawn from the reservoir, through a'suitable heat exchanger,V 92*- where-said liquid comes in contact with coils or the like of afl-refrigeration system for cooling the liquid. The chilled liquidis then pumped by means of` apn-mp 93.through-al pipe 94-leading to spray pipesl s-that are located inthe bin vadjacentfthe'cover I9. Suitable valves 96Lare provided-in` the line `infor-controlling the spray-and. quantity of water-delivered vtol the bin 5: Material .isfsupplied .through thechute 22 tof -the bin 5 and-:thefchilled water sprayed thereon for flow downwardthrough the material in the bin. A- baiile or' deflector: 91-diverts'all ofthe material and'fli'quid over the grizzly 81 whereby substantiallyia'llf .offthe'water is drained'from the materialf.: Thiswater circulation: systeml is of the' balanced h'ead type to reducethe power required. for; circulating the ywater in the system andxthe chilledrl water' iiowing over the material. and throughsame absorbsthe heat therefromisoV the material moving over the grizzlyis Wet: andis cool'edi,i.forrexampletorapproximatelyf 60 F. A'-

portion".y of fthe @chilled water.' fromr the pump 9311' is selectively directedi'through.a1.coil 98,.the rei-'f The waterv sprayed onfthef 11 turn of which is connected with the pipe 89. Air is drawn over the coil 98 by a fan 99 and discharged through a duct |00 which extends into the bin 5 between the grizzly and the spout I2, said duct 00 terminating in a downwardly directed frustro-conical outlet member IOI, the coils 98 removing moisture from the air passing therearound causing the air discharged through the outlet member |0l to be relatively dry and chilled, whereby the air moves through the material in the bin providing evaporation for additional cooling of same. The location of the outlet member causes the air to dry the material before it reaches the spout l2 and the air moves upwardly through the material and out to the atmosphere through a stack |02 which has a damper 103 for controlling the opening therein. The cooling and the evaporation effected by the air delivered to the material adjacent the spout will further reduce the temperature of said material to suitable temperatures, for example 40 to 45.

While the apparatus specifically described is for using my invention in the cooling of aggregate, it may be also used for the cooling and drying of other materials. For example, foods such as peas and the like may be precooled, dried and then frozen by the application of fluids in stages wherein the temperature and moisture content of the fluids are regulated.

It is believed obvious that I have provided a method and apparatus for cooling of material as it moves through the individual bins and also controlling the moisture content in an efficient and economical manner, that is fiexible to meet varied conditions and specifications as to temperatures of the materials.

What I claim and desire to secure by Letters Patent is:

1. The method of conditioning a large volf ume of material consisting of individual particles moving downwardly through a confined area by altering the temperature thereof, including applying chilled water to the material to thoroughly permeate same and intermingle in direct contact with the individual particles, draining excess water from the material, and delivering air to the wet material for movement therethrough countercurrent to the application of the water, said air being in sufficient volume to substantially evaporate the water remaining in the material and cool the particles in the volume of material whereby the temperature and moisture content of the material leaving the confined area are substantially uniform.

2. The method of conditioning a large volume of aggregates consisting of individual particles slowly moving downwardly in a confined area by altering the temperature thereof for incorporation with other ingredients in a concrete mix, including applying water to the aggregate as it enters the confined area cooling and drying air, delivering the cooled dry air to the wet aggregate for movement therethrough countercurrent to the movement of the aggregate through the confined area, said air being in sufficient volume to substantially evaporate the water applied to the aggregate and cool the particles in the volume of aggregate, and controlling the quantity of water applied to the aggregate in accordance with the relative moisture content of the air leaving the confined space whereby the temperature and moisture content of the aggregate leaving the oonned area are substantially uniform.

3. 'Ihe method of continuously conditioning a large volume of material consisting of individual particles as it gravitates through a confined area, including wetting the material as it enters the confined area, cooling and drying air, selectively delivering the cooled dried air to the material at spaced points in the confined area for movement through the material, said air being in greater volume than necessary to substantially evaporate the water from the wetted material for latent cooling of the material, and controlling the wetting of the material as it enters the confined area in accordance to the relative moisture content of the air being released from the confined area whereby the temperature and moisture content of the material leaving the confined area are substantially uniform.

4. The method of continuously conditioning a large volume of material consisting of individual particles as it gravitates through a confined area, including wetting the material as it enters the confined area, cooling and drying air, selectively delivering the cooled dried air to the material as spaced points in the confined area for movement through the material, said air being released from the confined area adjacent the entrance for the material, said air being in greater volume than necessary to substantially evaporate the water from the wetted material for latent cooling of the material, the excess air effecting additional sensible cooling of the material, and controlling the wetting of the aggregate as it enters the confined area in accordance to the relative dry and Wet bulb temperatures of the air being released from the confined area whereby the temperature and moisture content of the material leaving the confined area are substantially uniform.

5. The method of continuously conditioning a large volume of aggregate as it gravitates through a confined area for incorporation with other ingredients in a concrete mix, including wetting the aggregate as it enters the conned area, cooling and drying air, selectively delivering the cooled dried air to the aggregate at spaced points in the confined area for movement through the aggregate in countercurrent relation to the movement of the aggregate through the confined area, said air being released from the confined area adjacent the entrance for the aggregate, said air being in greater volume than necessary to substantially evaporate the water from the wetted aggregate for latent cooling of the aggregate, the excess air effecting additional sensible cooling of the aggregate, and controlling the wetting of the aggregate as it enters the confined area in accordance to the relative dry and wet bulb temperatures of the air being released from the conned area whereby the temperature and moisture content of the aggregate leaving the confined area are substantially uniform.

6. Apparatus for conditioning granular material comprising, a bin adapted to contain a quantity of granular material and arranged for gravitation of said material therethrough, said bin having a controlled outlet for the material adjacent the lower portion of said bin, an air cooling device, means for supplying cooling medium to the air cooling device, means for moving air through the air cooling device and selectively delivering said air into the material at spaced levels therein for flow upwardly through said materials, and means for controlling the quantity of air and the temperature of same dev spaced amazon livered to the material. .to `cool Ysaid material whereby the material .passing through Athe .outlet of the bin is substantially uniform intemperature.

7. Apparatus for conditioning granular material comprising, a bin adapted to contain a quantity or" granular material and arranged for gravitation of said material therethrough, `said `bin having a controlled outlet for the ymaterial adjacent the lower portion of saidbin, means lfor directing material to the bin, said material being maintained above a predetermined minimum level in the bin, means for wetting the material in the upper portion f the bin, an air cooling device supported adjacent the bin, means for supplying a cooling medium to the air cooling device, and means for moving air through the .air cooling device and selectively delivering it in .the material at spaced levels therein for flow upwardly through said material, the cooled air being of suiiicient volume to substantially dry the wetted material for latent cooling of same whereby thematerial passing through the outlet .of the bin is substantially uniforml in temperature and moisture content.

8. Apparatus rfor conditioning granular material comprising, a bin adapted to contain a quantity of granular material and arranged for gravitation of said material therethrough, said bin having a controlled outlet for the material adjacent the lower portion of said bin, means for directing material to the bin, said material being maintained above a predetermined minimum level in the bin, means for applying liquid to the material in the upper portion of the bin, means for controlling the quantity of liquid applied to the material in accordance to the wet and dry bulb temperature at the upper portion of the bin, an air cooling device supported adjacent the bin, means for supplying a cooling medium to the air cooling device, and means for moving air through the air cooling device and selectively delivering it in the material at spaced levels therein for flow upwardly through said material, the cooled air being of suiiicient volume to substantially evaporate the liquid in the material for latent cooling of same and further sensibly cool said material whereby the material ypassing through the outlet of the bin is substantially uniform in temperature and moisture content.

9. Apparatus for conditioning Ygranular material comprising, a bin adapted to contain a quantity of granular material and arranged for gravitation oi said material therethrough, said bin .having a controlled outlet for the material adjacent the lower portion of said bin, means for directing material to the bin, said material being maintained above a predetermined minimum level in the bin, means for spraying liquid into the upper portion of the bin onto the material therein, means for controlling the quantity of liquid sprayed into lthe bin in accordance to the wet and dry bulb temperature at the upper portion of the bin, an air cooling device supported adjacent the bin, means for supplying a cooling medium to the air cooling device, means for moving air through the air cooling device and selectively delivering it in the material at levels therein for ilow through said material, and means for controlling the volume and temperature of air delivered to the material to substantially evaporate lthe liquid in the material for latent cooling of same and further sensibly cool said material where-fy upwardly 114 by the material passing through the outlet of the .bin is :substantially uniform in temperature and moisture content.

l0. Apparatus for continuously preconditioning aggregates, sand and the .like consisting of individual particles for incorporation with other Aingredientsin a concrete mix comprising, a plu- .rality of adjacent bins adapted to selectively con..

tain quantitiesof aggregates, sand andthe like vand `arranged v'for gravitation of `said material therethrough, each .of `said ybins having a controlled :outlet adjacentthe lower portion thereci, means for selectively directing aggregates, sand and thelike to the respective bins whereby the material contained in the respective bins vis maintained above a predetermined minimum level, an air cooling device supported Aadjacent each of the vrespective bins, means for supplying cooling medium to the air cooling devicesmeans for individually controlling the cooling medium supplied to Athe `respective .cooling devices for regulating the temperature thereof, a pluralityof air ducts connected with the .air cooling devices of the respective bins and terminating in vertically spaced outletsin said bins, and means for moving air through the air cooling devices and delivering the air ithrough the ducts to the 1respective bins for flow upwardly through the material therein whereby the material is cooled and maintained substantially uniform ini temperature until it passes through the outlet of vthe respective bins.

1l. Apparatus for continuously preconditioning aggregates, sand and `the like'consisting'of individual particles'for incorporation with other ingredients in a concrete mix comprising, a plurality of adjacent bins adapted to selectively contain quantities of aggregates, sand and the like and arranged for` gravitation of said material therethrough, each of said bins having acontrolled outlet adjacent the lower portion thereof, means for selectively directingaggregates, sand and the like tothe respective bins whereby .the material .contained in the respectivebins is maintained above a predetermined minimum level, means in each of the bins for delivering liquid into the upper portion thereof `onto the material therein, means for individually controlling `the quantity of liquid delivered .into `the respective bins in accordance to the vwet anddry .bulb temperature at the .upper portions of `the respective bins, a plurality of air ducts extending into the rrespective bins and terminating in vertically tent until it passes through the outlet of the respective bins.

'12. Apparatus for continuously preconditioningaggregates, sand and the like consisting of individual particles for incorporation with other ingredients in aconcrete mix comprising, a plurality of adjacent bins adapted to selectively-contain quantities of aggregates, 'sand and the like and arranged for .gravitation of said ymaterial therethrough, each .of said bins having a controlled outlet adjacent the lower portion thereof,

means for selectively directing aggregates, sand `and vthe like vto therespect-ivebins whereby the material contained'in the respective .bins ris maintained above a predetermined minimum level, means in each of the bins for spraying liquid into the upper portion thereof onto the material therein, means for individually controlling the quantity of liquid sprayed into the respective bins in accordance to the wet and dry bulb temperature at the upper portions of the respective bins, an air cooling device supported adjacent each of the respective bins, means for supplying cooling medium to the air cooling devices, means for individually controlling the cooling medium supplied to the respective cooling devices for regulating the temperature thereof, a plurality of air ducts connected with the air cooling devices of the respective bins and terminating in vertically spaced outlets in said bins, and means for moving air through the air cooling devices and delivering the air through the ducts to the respective bins for flow upwardly through the material therein, the cooled air being of greater volume than that required for substantially evaporating the water in the material for latent cooling of same whereby the material is further sensibly cooled and maintained substantially uniform in temperature and moisture content until it passes through the outlet of the respective bins.

13. Apparatus for continuously preconditioning aggregates, sand and the like consisting of individual particles for incorporation with other ingredients in a concrete mix comprising, a plurality of adjacent bins adapted to selectively contain quantities of aggregates, sand and the like and arranged for gravitation of said material therethrough, each of said bins having a controlled outlet adjacent the lower portion thereof, means for selectively directing aggregates, sand and the like to the respective bins whereby the material contained in the respective bins is maintained above a predetermined minimum level, means in each of the bins foi` spraying liquid into the upper portion thereof onto the material therein, means for individually controlling the quantity of liquid sprayed into the respective bins in accordance to the wet and dry bulb temperature at the upper portions of the respective bins, an air cooling device supported adjacent each of the respective bins, means for supplying cooling medium to the air cooling devices, means for individually controlling the cooling medium supplied to the respective cooling devices for regulating the temperature thereof, a plurality of air ducts connected with the air cooling devices of the respective bins and terminating in vertically spaced outlets in said bins, means for moving air through the air cooling devices and delivering the air through the ducts to the respective bins for flow upwardly through the material therein, the cooled air being of greater volume than that required for substantially evaporating the water in the material for cooling of same and carrying latent heat from the material in the air whereby the material is further sensibly cooled and maintained substantially uniform in temperature and moisture content until it passes through the outlet of the respective bins, stacks communicating with the upper portions of the respective bins, and means in said stacks for controlling the escape of air therethrough.

14. Apparatus for continuously preconditioning aggregates, sand and the like consisting of individual particles for incorporation with other ingredients in a concrete mix comprising, a plurality of adjacent bins adapted to selectively contain quantities of aggregates, sand and the like and arranged for gravitation of said material therethrough, each of said bins having a controlled outlet adjacent the lower portion thereof, means for selectively directing aggregates, sand and the like to the respective bins whereby the material contained in the respective bins is maintained above a predetermined minimum level, an air cooling device supported adjacent each of the respective bins, means for supplying cooling medium to the air cooling devices, means for individually controlling the cooling medium supplied to the respective cooling devices for regulating the temperature thereof, a plurality of air ducts connected with the air cooling devices of the respective bins and terminating in vertically spaced outlets in said bins, means for moving air through the air cooling devices and delivering the air through the ducts to the respective bins for flow upwardly through the material therein whereby the material is cooled and maintained substantially uniform in temperature until it passes through the outlet of the respective bins, stacks communicating with the upper portions of the respective bins, means in said stacks for controlling the escape of air therethrough, means on the air inlet of the air cooling device connected with the upper portion of the bin for providing the communication therewith whereby air is drawn from the respective bins through the air cooling device for recirculation through the bins, and means for controlling the proportions of the make-up air and recirculated air passing through the air cooling devices.

15. Apparatus for continuously preconditioning aggregates, sand and the like consisting of individual particles for incorporation with other ingredients in a concrete mix comprising, a plurality of adjacent bins adapted to selectively contain quantities of aggregates, sand and the like and arranged for gravitation of said material therethrough, each of said bins having a controlled outlet adjacent the lower portion thereof, means for selectively directing aggregates, sand and the like to the respective bins whereby the material contained in the respective bins is maintained above a predetermined minimum level, means in each of the bins for spraying liquid into the upper portion thereof onto the material therein, means for individually controlling the quantity of liquid sprayed into the respective bins in accordance to the wet and dry bulb temperature at the upper portions of the respective bins, an air cooling device supported adjacent each of the respective bins, means for supplying cooling medium to the air cooling devices, means for individually controlling the cooling medium supplied to the respective cooling devices for regulating the temperature thereof, a plurality of air ducts connected with the air cooling devices of the res ective bins and terminating in vertically spaced outlets in said bins, means for moving air through the air cooling devices and delivering the air through the ducts to the respective bins for flow upwardly through the material therein, the cooled air being of greater volume than that required for substantially evaporating the vwater in the material for latent cooling of same whereby the material is further sensibly cooled and maintained substantially uniform in temperature and moisture content until it passes through the outlet of the respective bins, stacks communicating with the upper portions of the respective bins, means in said stacks for controlling the escape of air therethrough, means on the air inlet of the air cooling device connected with the upper portion of the bin for providing the communication therewith whereby air is drawn from the respective bins through the air cooling device for recirculation through the bins, and means for controlling the proportions or" the make-up air and recirculated air passing through the air cooling devices.

16. Apparatus for conditioning a large mass of aggregates consisting of individual particles for incorporation with other ingredients in a concrete mix comprising, a bin adapted to contain a quantity of the aggregates and arranged for gravitation of said aggregates therethrough, said bin having a controlled outlet for the aggregates adjacent the lower portion thereof, means for directing aggregates into the upper portion of the bin, said aggregates being maintained above a predetermined minimum level in the bin, means for spraying chilled liquid into the upper portion of the bin onto the material therein, means for controlling the quantity and temperature of the liquid sprayed into the bin, means in the path of gravitation of the aggregate through the bin toward the outlet thereof for draining excess liquid from the aggregate,

means in the bin for directing 110W of the aggregate over said liquid drain means, and means for discharging cooled dry air into the aggregate in the bin between the liquid drain and the bin outlet for flow upwardly through the aggregate, the air being delivered in suiicient volume to substantially evaporate the liquid on the aggregate and further cool same whereby the aggregate passing through the outlet of the bin is substantially uniform in temperature and moisture content.

CLIFFORD H. CARR.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,264,610 Beardsley Dec. 2, 1941 2,309,035 Beardsley Jan. 19, 1943 2,360,468 Brown Oct. 17, 1944 2,365,352 Moitt Dec. 19, 1944 2,379,932 lSohoelilin July 10, 1945 2,409,896 Plummer Oct. 22, 1946 2,491,194 McShea Dec. 13, 1949