.- 2, 1952 W. O. KLlNE Z, 6 1 9 8, 0 2 AIR CONDITIONING SYSTEM Filed April 12, 1949 4 Sheets-Sheet 1

______

INVEN TOR. W. O. KLINE

ATTORNEY . 2, 1952 w. o. KLINE 2,619,802 AIR CONDITIONING SYSTEM Filed April 12, 1949 4 Sheets-Sheet 2

IN VEN TOR. W. O. K L W E

ATTORNEY - 2, 1952 w. o. KLINE 2,619,802 AIR CONDITIONING SYSTEM Filed April 12, 1949 4 Sheets-Sheet 3 FIG. 5

IN VEN TOR. W- O- KLINE

ATTORNEY Dec. 2, 1952 w. o. KLINE 2,619,802 AIR CONDITIONING SYSTEM Filed April 12, 1949 4 Sheets-Sheet 4

IN VEN TOR. W. O. KLINE

ATTORNEY Patented Dec. 2, I952 - 2,619,802

r

2,619,802‘ , “ AIR CONDITIONING SYSTEM’ ‘‘ Y ' William 0;,Kli1na Weyncsbw, 134-» essiéiiift-f'c FriclilComp'any; Waynesboro, Pa; a'corpora tibfi of Pennsylvania Application April12, 1949;~seriai?o.§8i,t5i 1 " 26 claims. (Cl. 62-4) _\ 1 . This invention relates to‘, the conditioning of rruit, preserves trie- appre; overa rdnge ‘ peruse or air and more particularly to the provision of ‘a time and with a minimum loss or weigh .v system adapted to maintain a_ space ‘or the air within an enclosure at speci?edconditions of temperature and relative humidity and within close limits. - vastly differe'iit'frioni e found ‘n eoniiitioiv‘ng The problem of maintaining proper conditions for 'ljiuhr‘a'ri 'cf'omfort For‘ examplaj the operation of temperature and ‘humidity or air conditioning at these smears“ is per‘ ‘rnie'd very close to for various purposes has eiiis't'ed for a long time, and in more recent years many‘ systems have 10 seturatioiifiiissib'le limits-“f aiidt vari‘é'fd ti'or'rmus" t be.v, much?iinerz't ’ . been devised and patented on various methods of On the other hand, in'eon‘ditioning' for’ human conditioning air. A large percentageor these comfort the operation is jurther‘frqm the satura systems have been directed to air conditioning tion line and therefore the controls need not be for human comfort‘. Empiricaleohditionsor a as sensitive. > Furthermore, the range or condi range within which the‘ ‘space’ sheum'be main 15 tions for: human comioruzas‘ recognized by vari-}' tained,‘ have been speci?ed. For eiiample with ous authorities; is considerably‘ wider‘ or greater certain prevailing‘ outside conditions vthe inside than those: permissible‘ in thé conditioning of temperature should preferably be on the order of certain commodities: ' I V. 70° F; and 50' per Cent relative hu?iidi?y. The im‘portarrce of preserving various commode‘ Apparently considerably less attention has 20 itie's. for relatively long‘ periods of time will be been given and certainly relatively new systems appreciated on re?ecti'onf'that often a product andv patents have directed to the condi can best be sold duringvthe elf-season‘ when sim tioning, of‘ a space for industrial purposes such ilar products are notionsthe market insubstantial 'as the storage or commodities‘ where the pre quantity, and that in large storage installations ' ferred conditions‘ have been of: order di-?e‘ring' 25 the loss of size. or‘ weight" of the product, even‘ if substantially in scope frd?i’tha’t 6f the human only inatheineighborhood-of. about‘ 5' .or 10' per comfort range"; ‘ _ _ cent-results in substantial loss. The present invention’, and applicationvis' di An object of the present’ invention’ is to‘ pro rected to the provision of a system for maintain vide' ari'air conditioning systeirr including means‘ ing a space at‘ a temperature and relative humid 301 capable of conditioning air within an‘ enclosure at ity best suited for the storage‘ of a commodity a relatively high humidity ‘and a-rela'tivelyv low or food having a very large water’ content, such temperature. > ' ' as‘ apples._ . A further ‘object of the invention is to' provide It has been found that in ‘order’ to vr'flail'ltain means‘ wherebya' commodity may be stored for stored apples in thefbest condition for the longest - a relatively long-period of-time‘ and; its‘ size,‘ time and with minimum loss of weight by dehy weiahticompositi-on and appearance substantially dration; certain optimum conditions‘ are both de maintailnedan ‘ ' ~ sirabl'e' and necessary.‘ In order to’ accomplish Another object of‘the invention to‘ provide‘ these results, the temperature should be low means ‘for ‘condition-ing- the spacelin which’ a: enough to prevent the substantial growth of product isstored inforder that t-he‘loss" of moisture in-the product wiuibe-aminimum: : bacteria and preserve therfrui't in its original . A further; object “of the inventioniistoprovide state as nearly as’ possible but without impairing a system; forv conditioning ‘a-stora'ge space for the quality and texture by a-enang'e ofstate, such commodities j in- which the‘ temperature, relative as’freez'ing; and the humidity must be kept rela humidity, andgventilation are“ controlled so" that“ tively high to prevent excessive evaporation of the commodities are preserved infsubstantially moisture. their originalcondition'. > . ' Although: this invention isrpriinaril-y' ‘directed A: still- further objector. the‘invention ‘is ‘to'pro'-‘ to' the preservationofcommodities withoutfreeze vide- a; yearuarorund; ‘air conditioning’ system“ for ing, it- is- obviously applicable to‘ other tempera commodities which i‘sladapted temperate e'?i-‘ ture ranges including those-at vwhich a; given ciently and on a relatively-l'ar’ge'or‘smalfscalé' commodity is- normally the‘ frozen‘ state. It has‘ been found that a' dry bulb temperature’ of about 32° F; and-‘a; relative/"humidity of5abou't1j 8'5 pen ‘cent; together‘ withflow‘ air: velocity the 2,619,805? - ' V. " ‘ ~ 3 4 which is adapted to maintain close control of the are connected to the supply header I5 and have conditions and to operate the various components discharge lines I1’ and I1” leading to their re of the system in the most e?icient manner. spective evaporators. Similarly a header 3I ex These and other objects of the invention will tends from the hot gas line 24 and is provided become aparent from the following description with branch lines 32 and 33 leading to their re taken in conjunction with the accompanying spective heat exchange elements of other hu drawings, wherein: midifying units. The branch lines are connected Fig. l is a schematic diagram of a system con in parallel so that any ‘combination of one or structed in accordance with the present'inven more in operation is possible. _ tion, the left hand portion being a layout of the 10 In operation, the compressors receive refriger refrigeration and air condtioning units and. the ant gas through the suction line 2I and discharge right hand portion illustrating a vertical section it through the line II to the condenser I2 where through a building in which ducts from the air it is lique?ed. Passing from the condenser I2 and conditioning system are positioned; the receiver I3’ the liquid refrigerant is expanded Fig. 2, a partial schematic layout of a modi?ed 15 through the expansion valve 20 and goes into the system; evaporator coil I8 where it cools the air passing Fig. 3, a vertical section through a humidi?er over the coils. The gas from the coils then enters of a modi?ed construction from that shown in the suction line 2I to the compressor I3 or I0’. A Figs. 1 and 2; portion of the hot gas from the compressor may Fig. 4, a View similar to Fig. 3, of a modi?ed 20 be by-passed around the condenser and to the humidi?er having its sump below the ?oor level; heat coil 25, located in the humidifying unit; the Fig. 5, a fragmentary schematic layout of a gas, giving up heat to the recirculated water in modi?ed system; and, the humidi?er, is thereby liquefied and conducted Fig. 6, a diagram of a control system employed through the liquid lines 26 and 2'! to the expan with the apparatus of the present invention. sion valve 30 and the evaporator IS. The invention is primarily directed to an air conditioning system, including a refrigeration The air conditioning chamber system, an air conditioning chamber including a The cooling unit.--In order to control the tem cooling unit and a humidifying unit, an air duct perature, relative humidity, and velocity of the system communicating with the space to be con 30 air circulated through the conditioned space, an ditioned, and controls for the system. air conditioning chamber 40 is provided which in cludes cooling and humidifying units 4| and 42 The refrigeration system in parallel in the chamber. The chamber has a The refrigeration system, adapted for cooling return air opening 43, and discharge openings 44 the air within the space, comprises compressors and 45 for the cooling and humidifying units re I0 and I0’ in parallel and having a. discharge line spectively. Positioned near the inlet 43 is a main i I in which an oil trap I I’ is located, the line I I fan or blower 46, powered by a motor 47'. The leading to a condenser I2 connected by a line I3 blower 43 has diverging walls 41 and guide vanes to a receiver I3’. From the receiver I3’ 9. liquid 156’ on its outlet which direct its discharge to a supply line I4 leads to a header I5 for supplying cooling chamber 48. refrigerant to a conduit I6 which leads to a re Positioned in the cooling chamber 48 adjacent ceiving pipe I‘! of the evaporator coils I8. Posi the evaporator I8 of the refrigeration system are tioned in the line I6 are an electric control valve pipes 49 which are adapted to spray water, brine, I 3 and an expansion valve 20. ' or the like over the coils I8. A tank 50 is posi tioned under the coils I8 to receive the liquid. From the coils I8 a suction line 2I extends to 45 the compressors. Located in the suction line is From the tank 58 a line 5| is connected to a pump a motor actuated modulating control valve 22, 52 powered by a motor 53. A return line 54 leads and a spring loaded back pressure valve 23. from the pump to the spray pipe 49. These may be combined into a unit if desired. A fresh air inlet 56 is provided in the return A branch line 24 is connected to the compres air line 92. from the space in order that outside sor ‘discharge line I I between the compressor and air may be mixed with the recirculated air. the condenser and leads to a heat coil or heat Thersystem shown in the drawings is particu exchange element 25 located in the humidifying larly for a water spray defrosting system, it being unit. From the heat coil a conduit 26 connects understood that the invention also contemplates the use of other defrosting media such as brine the coil to a liquid supply header 2‘! which is con 55 nected to the conduit I‘I leading to the evapora or the like. Where brine is used by spray may be tor coil 18. Electric control valves 28 and 29 are operated without stopping operation of the main located in the hot gas line 24 and the liquid fan or blower and suitable ba?‘les are used be supply line 21, respectively, and an expansion igween the spray and the exit of the cooling cham er. valve 30 is also located in the latter line. 60 An electrical control valve 29’ is shown on the The humidifying unit.—In parallel with the water line going into the condenser I2 which re cooling unit is the humidifying unit 42. The unit ceives water from a pump. If desired the Water includes a fan or blower 60 powered by a motor supply may be from a main, and it's intake to the 6 I. The inlet of the blower for the layout shown condenser controlled by a condensing pressure 65 is near the return air opening 43 of the air con actuating valve. ditioning chamber and has diverging discharge It will be apparent that the system described directing walls 62 directed to the main humidify is adapted to supply refrigerant to a cooling unit ing chamber 63. Located in the main humidify in which the evaporator I8 is positioned, and to ing chamber is the heat exchange coil 25 in which a humidifying unit in which the heat exchange 70 hot gas from the compressor I0 is adapted to be element 25 is positioned. received and condensed. The invention contemplates that one or more The humidifying unit has a water supply tank cooling and humidifying units may be supplied 64 in which a pump 65 driven by a motor 66 is with refrigerant from the same refrigeration sys positioned. The. pump is adapted to circulate tem. For this purpose branch lines I6’, I6", etc., 75 water from the tank through‘a conduit 6‘! to pipes .7 es item which the métstamhioehi ‘that we "u; may lie 10f .it'he rdr’aéw-‘ihré?éhrdt 321th“ and .‘Over the coil ‘25; The Water which is not‘ Y through "type, that yidiseloseii ‘being ‘the former. taken up by the air passing through the iehamber Although --a girawethrough humidi?er/may he vem is drained-hack by ‘the tank 64 and reeireulated. »ployed, the {?rst cost ‘of/thesjsijerh empipyipge ,=A resistance type electric ‘heater 95 ‘having a push-through type ‘is loyver and. the-air distribu thermostat. 91 ismositioneel in. thatarnk and tion system ‘maybe ~_smjaller7as>-less air ‘is required adapted to maintain the temperature-oi the Water _ for circulation because it leaves-‘the push-through above freezing in the event that vthe heat‘obtained unit in ‘a saturatefi Condition. Therefore, 'to from the ‘coil ‘25 is i'nsu?i-eient, 1and during periods meet the v‘ar-yingivneeds, ‘differenteor'iibinatioris of 10 the units may be employed. 1 - ‘ I whent ‘ Positionedbetween'thezhumidi?erzspray the 'unitis-idle. . , , - ' .' and, the V W'Ifhe units 41-6 andll shown-in-Fig.v5liinclude discharge 45 is an eliminator 101?; baffle 69 vfor re "elements sirnilarjtofthose'shotéin Figs.) '1 and 2. . moving entrained droplets. ‘Water fis-va‘daptedto Insofar as the elements ‘ares il'ar, those [for :besupplied through :a line ‘ID, 'a *float, valve-‘ll the unitllare vdis‘ti‘ng'uishecl With a sin'all “it” '(Fig. ~3‘) V ‘controlling. theslev‘el :of the liquid in the 'su'?ixed to thefnumeraltahd these v't-‘ofthfe unit 16 tank. The invention'conter-riplates the use’ offthe with a'ysmall “eb’j sii?ikedto ‘the‘nunieir‘al. ' T ' water tank either above the surfaceiof'thevground During preeooliin‘g ‘other; times tvheh the or below, and Fa ‘horizontal unit Yas-i‘n Figs. -1.=and 2, eeolinggloa‘ol is ‘unusually heavy Iliquid ‘re'ffi'g'éraht "or vertical‘, as in Figs. ‘3 allele‘. Although the in ' reoeived. through the‘ fiii'pe T134361, i‘is "c'oiriifet‘e‘d dividual elements of the'u'nits of Figs. Bandfllare 20 through cgnneq'uons?fliqana m; ,th‘ro?eh the ‘substantially ‘identical with, those of Figs. 1 find jQ'OQ1iIlg'_j¢Oi1S "I817! and 18b in parallel and out 2, ‘and with ‘each ‘other, the ‘reference “characters -, thijough the; ~conhee7tio’ns 2m and '21"! b through of 'eo'mmon mechanical elements in Figs. 3 "and 4 their respedtive modulating ‘valves zzat'ana’ 22b are ‘designated With'a'prim‘e (’) vand niouble ip'rime to -_a cdmrrion___suction "line leading to the coin (’ 'v) -, respectively, ‘for ‘itlistinotio’n. 25 =pres_sor. Atter the cooling load ‘has "been ireduee‘d Figs. 3 and 4 illustrate ‘vertic'ai‘type ‘h‘uinidi?ers, to the holding, ‘condition the the 11b may be the former having ‘a ‘above the T?O'or or closed and‘ the line 24'!) ‘shown in ‘phantom dpérred ground level and the latter having a ~‘s'u'r'np below . to conduct hotycohipr'essed' gaseous refrigerant the g'i‘bund level‘. ' The former is ljélli‘?idularly ‘ through the coil 717819.; The refrigerant ‘may “be adapted for use in'ii'nst'allationls ‘above vthe ‘ground 30' condensed ‘in the coil and ‘returned 'throug'hithe floor and Where "it is hot ‘feasible OT ‘desirable to line -2-‘I;b_'sho:w”r;1___in phantom 'to ‘the line T421, to alter the constr'tmu'o‘ 'of the building materially. the >coi1\ Isa.’ Thesiiray?gb :is‘ empib'y'e'd- only The walls of the shifty) are-er ii‘elat‘ively great during the vperiods when‘th'e unit ‘[6 is'fu‘se‘d for thickness in order to insulate ' e Water therein humiditying rather: than ‘cooling, Suitable ‘teleo from the below freezihg tentee'r'atures l?r'evailling trical pontrols are diagrammatically ‘Shawn. The :o'ut‘side'of the sump. I ’_ unit 16 may he employed ,‘with ‘the foorine'ot'ions th‘e humidi?er shown in v‘Fig. "4, ‘the i's-u‘inp ,zab ancl_~2lb,“the-hea't neb’e'ss'a'ri'y ‘forthe e'v'ainb'r'a is placed beneath the le‘ifel of the ?oor ‘or "ground tionJo-f the moisture (:lurin'g hifriiidi?éation ibeir'ig and 7therebyfinsulatei'i mm the rreézing te'm ' obtained from the fan ‘motor, ‘the ‘water in "the 40 tanlgjalso meiang'up 'heatwhenrediiired Ti‘orhfthe ‘ perature of the 'AfcliVidi-“ng ‘Wall :12 ‘imagi ‘ e011 95b, ‘7 apAlthough ‘net she-‘we ‘in the timing, tioned in the ‘sump to provide a "eh‘ai‘nbe'r 1:3 :for suitalgle defrostingfineans may ‘be ‘provided "for thepump separate irom the ehamher ‘H itiirlthe water. ,The invention v‘conteiri'nil'ates the -'pro ' coil~l8a. ‘ V I, vision "of a common ‘sump-to “ ' waterifar all "Th-enact system'a'nd ’-t7ie'\'00nditio1£ed space "of the elements of "the system-requiring the-same, The 7s‘ystehil?eliitléd iii {the ‘rifese‘nt ‘invention represented by supply pipes 15 in the sump. For ‘contemplates ‘the "pfOVi's‘i'O'n of ?llets “Which *"e‘o‘n 'eXa-mple,_ ‘the condenser ‘cooling water may he vey air to and from ‘the eohditidnetfsziiab'efafnd vpiglet}. to the sump and then-to a "through the i'a'i‘r 'tioiiing ‘bhaiii‘be‘r in which tower prior to return to the “condenser; if awater a the, cbdlihg ‘ana h'l'ii'riidifying “units ‘are heated. ‘spray is used’ to defrost the eome‘reqiis; it may 50 In ‘the I'brerened 'fo‘i‘m of ‘the “intentitinjinfwhich be supplied from ‘the sump, iii ‘add’ ion to the ‘the 'bl‘dw'e‘i‘fi's 'e'mbllbyéd‘aheaad "of the ‘c'doll?g‘btiils supply required for use in thef ' v r. > ‘r I8, and therefore ‘ijii‘shfe's the‘ai'i‘ 'th'eréthi'diig‘h, _ The foregoing discussio' has Heat with the separate ducts are ‘required for ‘the discharge of use of a pair of compressors paralleljfor’sup the cooling and huinidifyingunits. The duct 813 plying refrigerant to the cam-me eo‘i-l of’a' cooling 55 leading; from‘ the discharge ‘44 ofthe cedimg units imit and for supplying compressed _-'ga's to ra-heat ‘ jsgof relatively large size compared ‘tothe ‘duct ing coil, {or a humidi?er unit be'si’cie the cooling :31 le‘adinggfromth‘e discharge ‘#5 tr ‘the ‘hufnidify vunit. The invention‘ also "commutes the inter ing unit. , lngtheqiiish-throu'gh "system ‘shevmm changeability of cooling vantieinurhi'd'i’iyilne units. Fig.v -1, it is necessary to ‘hav'e'i‘sep'arate 'élu'ct's ‘be During loading and precooling the "?'ema‘nd for 60 cause bf the psychometric eohditionh of tli ' refrigeration is great ‘compared to ~tl'ieit jreq'aired oischargeql from each of teatime. fOt- ‘k for ‘holding the ‘desired temperature ih the space the mixing or‘v the saturated air ‘from the Cooling vafter loading “and preb'ooli'ng. onyx/try sat-is unit would result ina'iniiturehavihé a'téhiiiérh iacter'y seluudn ‘for lir'reeting the ‘demand 'auring ture belowwthev ‘dew ‘point thereof ‘whi-eh would loading has been ‘to ‘employ ‘edoli‘nfg ‘units in bar 65 ‘cause condensation a ‘chemist "duct. allel as shown inFig. '5, ‘and to operate one as ‘a ,_ The ducts!!!) and _a1_' eiejie'beiveu'in the'v'co‘n‘di humidi?er during holding l7p'erio'ds'when the de Ationed spacev_83"which has’x-flofor-eeilin'g“iiartitidns mand for ‘cooling is-relatively ‘low. 1 - 8-4 andéoutside walls 85: Within thefeondit'ioned Although either or both of the units‘lm‘ay ‘be of space 133v the duct 81) hrah'che's out to br'ov‘ide'iini the "draw-through "orpush'eth'rou'gh type, a ‘pre form distribution of ‘ air to the “Space. It is ‘fp’bsi ferrecle arrangement is that shown-in} which _the tionegi near the ceiling _ an'dlias discharge ‘open unit 15 is of the pushethrough' type and is ings >85 tit-spaced. interjals'alé'rig‘ its ‘length. adaptegito operate either -as__ aheoolereor “as a humidi?er, apparatus and controls ‘being ‘so 9pro- . vided for it. The unit 11 besid-e'the‘interchange 2,619,802 7 8 ries a smaller‘ volume of air. Its openings 81 are measured by the thermostat I00. For the condie spaced or placed in staggered relationship from tions speci?ed, the room temperature after pre the openings 86 of the cooling air duct 80 in order cooling varies usually between 305° F. and that the discharge from the respective ducts is 30.75" F. not mixed until mixture with air already within Attached to the shafts of the modulating valve the space has taken place. Inasmuch as the motor are auxiliary single pole double throw humidifying duct 8I is of substantially smaller mercury switches I03 and I04. These switches cross-section and length than the cooling duct 80, are actuated by cams which are driven by the the total expense of providing a separate duct modulating motor shaft. In the embodiment is not substantially greater than that of a single 10 shown, switch I03 is connected by a lead I06 to but larger duct. a coil I01’ of a relay I01 having movable contact In Fig. 2, the blower or fan 46’ is placed after arms I08 and I09. From the coil I01’, a lead H0 the cooling coil so that air is drawn through the is attached to a power line III. The other con coil rather than pushed through as in the pre tact of the switch I03 is connected by a lead II2 ferred embodiment shown in Fig. 1. As the air 15 to a power line II3 which line II3 may be con is drawn through the cooling coil its temperature nected through a defroster timer I62 to one ter is reduced to that of saturation but after picking minal of the electric control valve I9. up heat in passing through the blower it is not The movable arm I08 of the relay I01 has one saturated on discharge. The properties of the air of its contacts attached to a lead “3' which is discharged by the cooling and humidifying units 20 attached to the other terminal of the electric shown in Fig. 2, are such that they may be mixed control valve I3, and the other to a lead I23 without producing condensation. Therefore, which is attached to a movable arm I I4 of a re both the discharge ducts 88 and 89, provided for lay II5 having a coil H6. The other contact the cooling and humidifying units, respectively, of the arm H4 is connected to a lead I24 which feed into a main duct 90 which is received in the 25 is attached to the starter I25 of the motor 2I0 conditioned space. The duct 90 has a series of of the compressor I0. Closing of the contact spaced discharge openings within the space 83. arm II4 energizes the starting circuit I25 of the From the space 83 a return duct 92 leads from compressor I0. Upon energization of the start the discharge opening of the space to the receiv er the circuit through the electric control valve ing opening 43 of the air conditioning chamber. I9 is completed from the power line II3 going ' The overhead duct system is particularly‘ ad through the valve I9, the lead II3’, the contact vantageous for even conditioned air distribution arm I08, the lead 23, the contact arm N4, the of the type required for an industrial installation lead I24 and the starter I25 to the power line and drafts are substantially eliminated. A low III. It is apparent therefore that the starting velocity, vertical, downward air flow from the circuit of the compressor I0 is in parallel with ducts is opposed by the vertical, upward heat and the electric control valve I9. moisture flow from the commodity in the space, Where a brine system is used, rather than a resulting in a relatively low velocity horizontal water system, for defrosting the pump may be air ?ow through the cross-section of the space, connected in parallel with the electrically con and the elimination of zones through which ven trolled liquid valve I9 and the compressor with tilation is inadequate. Thus an even distribution which the valve is connected in parallel in order of air is obtainable eliminating de?ciencies re that the operation of all three may be simul sulting from uneven distribution. Among the taneous. ' de?ciencies of prior systems was the freezing of The movable arm I09 of the relay I01 has one material stored near the cooling coil on the shady contact connected to a lead II1 which is at side of the space when the coils were operated to tached to a conductor I I8 connected to the start cool material stored on an opposite wall of the er II9 of a condenser water pump motor I20. space exposed to the sun. The other contact of the movable arm I09 is at In order that the system operate as efficiently tached to a lead I2I which is connected by a lead as possible, the exterior walls of the conditioned I22 to the starter II9. Actuation of the relay space include vapor seals and adequate insula 50 I01 closes the switches I08 and I09. The clos tion so that the high humidity within the space ing of the switch I09 connects the leads H8 and will not be dissipated through its walls. I22 ofthe starter I I9 of the water pump I20 and initiates the operation of the pump. The control system When the starting circuit of the pump I20 is The cooling unit controls.—Automatic controls completed, the relay H5 and a second relay I26 are provided for the cooling unit to maintain the having a coil I21 and a movable arm I28 are en air in the space within close limits of dry bulb ergized. The relays are of the time delay type, temperature and relative humidity, and to pro the relay II5 actuating its arm I 14 after a delay vide efficient operation of the system. A sche of two minutes, and the relay I26 actuating its matic hookup is shown in Figs. 1, 2 and 5, the de arm I28 after a delay of ?fteen minutes. The tailed system in Fig. 6. movable arm I28 has one contact attached to the Referring particularly to Fig. 6, a temperature power line H3 and the other to a lead I29 in controller I00 is provided which is responsive to series with a coil I30 of a relay I3I having mova thermostat bulb IOI positioned in the return air ble arms I32 and I33. The other side of the coil stream from the conditioned space near the open 65 I30 is attached to the power line III. One side ing 43 of the air conditioning chamber. This is of the arm I32 is connected by a lead I34 to a a conventional thermostat and preferably of the low pressure cutout switch I55 responsive to _ potentiometer type with a 3° differential in cycles. the suction pressure of the compressor III’; a Each cycle may be days or weeks in length de pending on the operating conditions. The ther lead I34’ from the switch is attached to the mostat is connected to the modulating motor op power line H3. The other arm is connected by erated valve 22 in the suction line 2I of the com a lead I35 to a coil I36 of a ?fteen minute time pressor I0. The operation of the valve in any delay relay I31 having a movable contact arm position between fully open and fully closed de I38. The other side of the coil I36 is connected ' pendson the temperature of the return air as 75 to the power line [I I. 2,619,802 The movable arm, I33 of the .relay I3I has a thetwo compressors is of su?lcient magnitude to lead I39- connected on one of the powerlines place the switches MI and I55 in, the “on” posi_-. goingto the compressor motor 2I.II,' and another tion, the compressor I0, associated with the lead I40 going to one side of a low presure switch switch I 4| will begin operation and the timing I41. A lead I42 from thefother side of the low relay I31 associated with the compressor III’ will pressure switch is attached to one side of a ca I be actuated. If after the expiration, of the time pacity control I43, and a lead I44 from. the other for which the timing relay is set, the suction side of the capacity control is attached to an pressure has not been reduced below the setting other of the power lines of the motor 210. at which the switch I55 breaks the contact, the The movable contact 1 I38 of the time delay compressor I0’ begins operation. After the pres relay I31 has one lead vI45 connected‘ to the power sure in the suction line is reduced below that at line H3 and the other, by a- lead I46 to a coil which the Switch I55 breaks contact the opera I41 of a relay I48. ‘The other side of the coil tion of the compressor I0’ ceases andthe com I41- is connected by a lead I49 to the power line pressor I0 operates atv full capacity until, its II I. The relay I48 has a movable arm I50, the 15 switch I4.I breaks the circuit. C j contacts of which are attached .to leads. I 5| and Under other operating conditions, Where the I54 to the starting circuit I52 of the compressor switches MI and I55, are initially‘ in the “on”. po motor 2I0'. When the switch I50 is closed, the sition, the operation of the compressor I0, may starting circuit of the motor 2I0’ is energized. reduce the suction line pressure su?iciently to The other mercury switch I04 which is actuat 20 turn the switch I55 to the. “off” position before ed by the modulating motor has its central pole the time delay relay has started the compressor I60 connected, by a lead IBI to the defrosting 'I?’s, operation. It is apparent, therefore, that system program automatic timer I62. One pole the speci?c arrangement of the pressure. switches I63 of the. switch is connected by leads I64 and andtime delay relays provide for economic op I65 to a low speed control in the starting circuit 25 eration of the compressors and for the prevention I66 of the main fan motor 41'. The other .pole of an excessive electrical demand byreason of I51 of the switch I04 is connected by a lead I68 substantially simultaneous starting of two or to the central pole of a single pole double throw more units. ' . mercury switch I10 operated by the humidity In a typical cycle of operation the sequence of control ‘or humidistat ‘I10’. 30 actuation of the various components associated The humidistat H0’ is positioned in the re with switch I03 is as follows. The closing of the turn air stream from the conditioned space in circuit in the switch I03 energizes the coil I0?’ order that it be responsive to the relative humidi of the relay I01. actuating the contact. arms I08 ty of the air returning 'from the space. In the and I09. The actuation of the contact. arm I05 embodiment which is particularly adapted for 35 closes the starting circuit I I9 of the condenser the storage of apples, the humidis'tat is prefer water pump motor I20. Operation of the water ably set at a mean of 85 per cent relative humidi pump motor I20 actuates, the time delay relays ty and has a range of 21/2 to 3 per cent on either I I5 and I26 associated with the water pump mo side. tor. After a short time delay, for example two As previously pointed out, the central pole, I69 40 minutes, to permitv the pump to?ll the water of the humidistat' switch is connected by the lead circuit, the contact arm_II4 of the relay H5 is I68. to a pole I61 of the single pole double throw actuated and, closes the starting circuit I25 of» switch I04 which is actuated by» the‘ modulating the motor of the compressor I0. This also com motor under controlof the thermostat I 00. One pletes the circuit to the electric control valve I0 pole III of the switchfI‘IB is connected to the in the liquid line which is in parallel with the lead I65 which is inseries with a slow speed con 45 starting circuit I25. .'After a further time de trol of the fanmotor 41'}. The other pole I‘I2 _of lay, for example, 15 minutes, the contact arm the switch I10 is connected by a' lead I13 to a I221‘I of the relay I26 closes a circuit tothe coil high speed control in the circuit I66 of the fan I30 0! the relay I3I. The relay I 3I thus has its motor 41'. A lead I14 from the fan motor con pair of contact arms I32 and I33 closed, and pro trol is connected to the program timer I62 and 50 videdthat the switch MI is in the “on” position, is adapted to complete the circuit from either the the capacity control I43 of the motor compressor low or high speed contacts I66 ‘of the fan motor I0 is energized, as is the coil I36 of the time de 41'. ' lay relay I3'I, provided that the switch I55 isin The aforementioned ‘pressure switches MI and the “on” position. After the ‘time delay for I55 which control the'capacity control and. motor 55 which the relay I3‘! is set, as for example 15 min starting circuits of the compressors I0 and‘ I0’ utes, has expired, the contact arm ‘ I33. of the respectively, are set to open their respective cir relay is closed, thus closing the. circuit I41, of the cuits at a relatively low pressure and to close relay I48.‘ This closes the contact arm I50 of them at a relatively high pressure. For example, the relay which closes the starting circuit I52 of the pressure switch I4I may be set to open at the motor I53 for driving the compressor I0’. 16 p. s. i._ ‘and to close at 22 p‘. s.‘i.; the switch In the operation of the fan speed control sys; I55 may 'b'e'set to open at 18 p. s; i. and close at tem. when the dry bulb temperature of the ‘space 40 p. s. i. This arrangement of the switches ad rises above that at which the thermostat 'I00is justs the compressor capacity'of the system to set, the modulating suction control. valve 22 the demand for refrigeration, the control system 65 opens in accordance with‘ the demand for cooling, disclosed being adapted to more than two com and the auxiliary switches I03 and I04 are actu pressors, obviously. ated. If the temperature rise or the demand for The pressure responsive switches are connected cooling is slight, as for example 1/5'of lithe con in the system with timingrelays in order to pre 70 trol valve 22 is opened onlylslightly so‘that a vent short cycling of ‘any one compressor and to small amount of cooling at high'ammonia'tem prevent the simultaneous starting of two or-more perature within the coolingcoil applied to the compressors. - _, air. -, . I . At the start of a typical cycle of operation, as High ammonia temperature results in the re suming‘that the pressure in the suctionline to 75 moval of less moisture from the air than with. low 2,619,802 11 12 a temperature and thus helps maintain the high are provided for the humidifying unit. These humidity. If the increase of temperature above include a humidistat I80 which is positioned in the thermostat setting is substantial, however, the return air stream from the conditioned the valve 22 will open further so that more cool space. It is connected by a line I8I to the motor ing takes place. If the relative humidity should starter I82 of the blower motor ‘6|. The motor exceed the setting of the humidistat I153’ the is connected in parallel by line I83 to the water switch II8 will close a circuit to the low speed pump motor 66 positioned in the tank so that control of the blower through the pole H9. If the pump will operate with the blower. there is a demand for cooling and humidity, how A differential type thermostat I84 has bulbs ever, the humidistat switch will close the con 10 I85 and I86 positioned in the return air stream nection to the high speed control of the blower from the conditioned space and the discharge through the pole I2 I. If the temperature of the from the humidifying unit, respectively. This air contacting the thermostat drops below its is set to operate on about 1/2". F. differential mean setting about a degree, in accordance with between the bulbs and by means of a suitable a preferred setting, the switch I04 associated with connections I81 and I88, operates a switch in the modulating motor closes the circuit through the thermostat I84 which controls the electric the pole I63 to the low speed control of the control valve 28 in the hot gas line leading to blower, regardless of the condition of the rela the heat coil 25 in the unit. ' tive humidity. Before this change of speed takes It will be apparent that in operation, the place the modulating valve 22 is practically closed 20 humidistat I80 in response to a demand for so that the ammonia temperature in the coil has humidi?cation will cause the blower 60 and been raised to almost its highest point and there water pump 65 to operate. The differential fore the speed change can be made in order to thermostat is set so that the, air leaving the save about 75 per cent of the blower power. unit is at substantially the same dry bulb tem Regardless of the temperature prevailing the perature as that entering. Therefore' the humidistat may change the speed of the blower humidifying unit may be set to follow the dry from high to low if the relative humidity ex bulb temperature of the air in the conditioned ceeds the instrument setting. Of course, after space whether the space is being precooled, the thermostat has changed the fan speed to loaded, or held at a steady temperature. Thus low the humidistat has no further effect on 30 the only e?ect of the humidifying unit on the the speed, but under these conditions, as a conditioned air is to add humidity as required. practical result, an inside relative humidity that By the use of separate blowers for the hu is considered too high is a remote possibility. midi?er and cooling unit, independent operation This may be corrected by proper adjustment of the units may be had, resulting in more ef of the controls. 35 ?cient overall operation. For example, when It is apparent, therefore, that during cooling cooling is not required the main blower may the ammonia temperature rises as the space be stopped and the small humidi?er blower op air temperature decreases, and that the refrig erated without recirculating water to maintain erant and space approach the same temperature. a small amount of circulation so that an average During cooling the suction control valve gradu 40 mixture ?ows past the controls. ally closes and the fan speed is reduced from' It is apparent that the present invention con high to low in accordance with the control set templates the provision of a system for maintain tings. When the thermostat is satis?ed as to ing the air within a commodity storage space cooling the compressor stops and the electric at a, low temperature and high relative humidity, control valve on the liquid line closes. and for providing low velocity, evenly distributed During winter, the outside temperature may air ?ow through the space. The system includes decrease the inside temperature below the in automatic controls which maintain optimum strument range setting. When this occurs the conditions in the space and at maximum oper relay is set to close the circuit to the high speed ating ef?ciency. circuit of the main blower in order that sub It will be obvious to those skilled in the art stantial heat is added to the space due to its that various changes may be made in the in operation. It is understood that in winter op vention without departing from- the spirit and eration a need for humidi?cation exists at scope thereof and therefore the invention is not nearly all times. ‘ limited by that which is shown in the drawings In practice, the main blower preferably has 55 and described in the speci?cation but only as a relatively large capacity in order that a smaller indicated in the appended claims. temperature differential of the air entering and What is claimed is: leaving the space may be employed. In this 1. An air conditioning system comprising a way dehydration of the air is reduced as the refrigeration system including compressing, con coils may have a relatively high temperature, densing, and evaporating means, a cooler for pro and more even temperatures in the space are viding heat exchange between the air and said possible. Because of the positioning of the ducts evaporating means, a humidi?er for the air, a in the space, a, slow air movement past the bypass from the compressing means to the evap stored product is achievable even with relatively orating means and including an element adapted large air movement. 65 to dissipate heat to the humidi?er, and differ The defroster timer I62 is of conventional ential temperature responsive means controlling construction and provides timing connections the transfer of heat to said element, said means which may be set to defrost the unit on a given ‘ being responsive to the difference in temperature cycle. The starting circuit 53' of the defrosting of the air before and after passing through the water pump motor 53 is connected by leads to 70 humidi?er, whereby substantially all the heat the timer and is adapted to operate through added to the air passing through the humidi?er a portion of each cycle. As the defrosting cycle is latent. is of conventional construction a detailed dis 2. An air conditioning system comprising a cussion thereof is believed unnecessary. refrigeration system including heat absorption The humidi?er control-Independent controls 75 and heat dissipatiQn means, an air conditioning 2,619,B02 ' 13. 14 unit including a cooler and a humidi?er having and provided with a common inlet and individual an inlet for return air and an outlet for dis discharge openings-means to force air received vcharge air, the heat absorption means being posi from the inlet through the units and to dis tioned in the cooler and adapted to absorb heat change the same through their individual dis from the air passing therethrough, a main blower charge openings, the air pas-sing through their provided for the cooler and. a second blower pro individual discharge openings being substantial vided for the humidi?er, the inlets of the blowers 1y saturated, individual ducts extending from being positioned adjacent the return air inlet of their discharge openings to a space to be condi the air conditioning unit and‘ adapted to produce tioned, branch ducts extending from the in the ?ow of air through the cooler and humidi?er, dividual ducts and supported near the ceiling of respectively, a space to be conditioned, individual the space, the branch ducts being provided with air ducts connecting the discharge of the cooler spaced outlets, the outlets of- the cooling ducts and humidi?er to the space, and a return air being staggered with respect to those of the duct connecting the space to the air conditioning humidifying ducts, and a return air duct con 15 necting the space to the common inlet. unit. . ' r. , 3. An air conditioning system comprising a 8. In an air conditioning system including com refrigeration system including heat dissipating pressing, condensing and evaporating means and and heat absorbing elements, an air condition connection therebetween including a suction line ing unit comprising cooling and humidifying from the evaporating to the compressing means, units, a heat absorbing element being in heat 20 a heat exchange chamber in which the evaporat exchange relation with the cooling unit, and a ing means is positioned, and a multispeed blower heat dissipating element being in heat exchange for'producing air flow through the heat exchange relation with the humidifying unit, a space to chamber, a control system comprising a modu be conditioned, discharge and return air ducts lating valve in the suction line, and means re connecting the space and the air conditioning 25 sponsive to the temperature and humidity of unit", means for circulating air through the space, the air entering the heat exchange chamber and ducts, and air conditioning unit, di?erential adapted to control the operation of the modu temperature means responsive to the dry bulb‘ lating valve, and multi-speed blower, whereby the temperature of the air entering and leaving the modulating valve is gradually closed as the tem humidifying unit and adapted to control the op 30 perature of the air decreases in order to increase eration of the heat dissipating element in the the temperature of the evaporating means, and humidifying unit, whereby the humidifying unit the speed of the blower decreases as the demand may add moisture to the air without substantial for cooling and humidifying is decreased. e?ect on its dry bulb temperature. -9. The structure recited in claim 8, and de— 4. The structure recited in claim 3, the cir 35 pendent connections between the temperature culating means including a blower in the hu and humidity responsive means and controlling midifying unit for forcing'air through said unit, the speed of the blower whereby the blower is whereby heat rejected from the refrigeration operated at a relatively high speed upon a sub system and that given up by the blower motor stantial demand for both cooling and humidify are received by the humidifying unit. 40 ing, and is operated at a relatively low speed 5. An air conditioning system comprising a when either the demand for cooling or humidi refrigeration system including connected com‘ fying is substantially met. pressing, condensing and evaporating means, an , 10, The structure recited-in claim 8, the air air conditioning chamber having the evaporat conditioning unit including a humidi?er in par ing means positioned therein and discharge and allel with the heat exchange chamber and pro return air openings, ducts connecting the open vided with a blower, means for circulating water ings to a space for air conditioning, a blower in within the humidi?er in contact with air pass the chamber having its inlet near the return air ing therethrough, and means for heating the wa opening and adapted to force air in heat ex ter" including a connection from the compress change relation with the evaporating means and 50 ing means to the humidi?er, the humidi?er be through the discharge opening, a modulating ing provided with independently operated con valve in the compressor suction line, means re trol means responsive 'to the humidity of the air sponsive to the temperature of the air entering and adapted to operate the humidi?er blower the chamber and adapted to gradually close the and water circulator upon a demand ‘for humidi modulating valve as the temperature of the air 55 ?cation, a valve in the connection between the is reduced whereby the temperature of the evap compressing means and the humidi?er, and orating means is raised as the return air tem means responsive to a ‘temperature differential perature is lowered in order to reduce condensa between the air entering and leaving the humidi tion on the evaporating means and whereby heat ?er, saidmeans controlling the operation‘ of the is added to the air by the blower prior to its pass 60 valve, whereby upon a demand for humidi?ca ing in heat exchange relation with the evaporat tion air is circulated through the humidi?er and ing means so that its relative humidity after in contact with the water, the differential tem passing the evaporating means is unchanged by perature responsive means maintaining the heat the blower. » I of the water such that the temperature of the 6. The structure recited in claim 5 and a hu air entering and leaving the humidi?er remains midi?er in the air conditioning chamber having substantially constant in order that the humidi its air circuit in parallel with that throughv the ?er may add moisture to the air in the system blower and evaporating means, the humidi?er as required but have substantially no effect on comprising means for adding moisture to the air its temperature. ' and a second blower having its inlet near the 70 11. An air conditioning system comprising a return air connection of the chamber and refrigeration system including connected com adapted to force air through the moisture adding pressing, condensing and evaporating means, an

means. _ air conditioning chamber comprising cooling and 7. In an air conditioning system including a humidifying means in parallel,’ a conditioned cooling unit and a humidifying unit in parallel space, ducts connecting the dischargeof the cool 2,619,802 15 16 ing and humidifying units to the space, a return 17. Apparatus for conditioning air for circu air duct Connecting the space to the air condi lation into a space in which the relative humidity tioning chamber, a modulating valve in the com and temperature are maintained at near satura pressor suction line, a main multi-speed blower tion and close to the freezing point of water, re for the cooling chamber and a second blower for spectively, comprising ?rst and second cooling the humidi?er, means responsive to the temper units each being provided with cooling means ature and humidity in the space and connected and blower means for causing air to flow through to the modulating valve and the multi-speed the units, the second cooling unit being provided blower, whereby the temperature of the evapora~ in addition with a humidifying means and con tor coil and the amount of air circulated there 10 trol means for selectively operating the cooling through may be varied in response to temperature or the humidifying means, whereby the units may and humidity conditions in the space. cool air during relatively large loads and where 12. In an air conditioning system a refrigera by the second unit may humidify air during rel tion system including heat absorbing and heat atively smaller loads. dissipating elements, a cooler adapted to provide 19. The structure recited in the preceding heat exchange between a heat absorbing element claim, the ?rst unit being provided with a blower and the air, and a humidi?er adapted to pro positioned between the cooling coils and the out vide heat exchange between a heat dissipating let of the unit and the second unit being pro element and the air, means for controlling the vided with a blower positioned between the in amount of heat supplied to the humidi?er by the 20 let and cooling and humidifying means. heat dissipating element, said means including 19. An air conditioning system comprising a a valve whose operation is controlled by differ refrigeration system including compressing, con ential temperature responsive means located in densing and evaporating means for a refrigerant, the air stream before and after its passage one or more air conditioning units through which through the humidi?er whereby substantially all air for circulation into one or more spaces is the heat added to the air by the humidi?er is passed, a cooler and a humidi?er in one or more latent.v air conditioning units, the cooler having an evap 13. An air conditioning system comprising a orating means in heat exchange relation there plurality of refrigeration systems each including with, a bypass from the compressing means to compressing, condensing and evaporating means, the evaporating means and including an ele a common suction means from the evaporating ment in heat exchange relation with the humidi to the compressing means, a cooler for each of ?er, means for circulating air from the air con the refrigeration systems adapted to provide heat ditioning units to one or more spaces, and means exchange between the evaporator and the air to responsive to the difference in dry bulb tempera be conditioned, and means for controlling the ture of the air entering and leaving the humid operation of each of the compressors, said means i?er for controlling flow through the by comprising pressure responsive elements located pass to the element in heat exchange relation in the suction lines of the various compressors with the humidi?er. and time delay means in combination with the 20. The structure recited in claim 19 and tem pressure responsive elements whereby operation 40 peratures responsive means in the air stream from of the various compressors is dependent on the the space to the cooler for controlling the cool demand for cooling in the individual coolers and ing eifect of the cooler. whereby a substantial time lag is provided be 21. An air conditioning system for the mainte~ tween the shutting off and the operation of a nance of a space at high relative humidity and compressor. a dry bulb temperature near the freezing point 14. The structure recited in claim 13, multiple of water, comprising a refrigeration system in compressors being provided for one or more of cluding heat absorption and heat dissipation the refrigeration systems, the pressure responsive means, an air conditioning chamber including means provided for each of the compressors be cooling and humidifying units, an air return and ing arranged to operate said compressors in se discharge means connecting the air conditioning quence, whereby the compressors will be actuated chamber with the space, a heat absorption means in sequence in accordance with a demand for re being in heat exchange relation with the cool frigeration and whereby a substantial time lag will ing unit and a heat dissipation means being in occur between the starting of operation by the heat exchange relation with the humidifying sequential compressors. unit, and means responsive to the diiference in 15. The method of conditioning air for circu dry bulb temperature of the air entering and lation into a space in which the relative humidity leaving the humidifying unit for controlling op and temperature are maintained at near satura eration of the heat dissipation means. tion and close to the freezing point of water re 22. An air conditioning system for the main spectively, which comprises passing air through 60 tenance of a space at the desired humidity and a humidi?er and a cooler, heating the humidi?er temperature conditions, comprising a refrigera and controlling the heating so that the dry bulb tion system including heat absorption and heat temperature of the air entering and leaving the dissipation means, an air conditioning chamber humidi?er is substantially the same, passing air including cooling and humidifying units in par through the cooler, and varying the cooling ef 65 allel, air return and discharge means connect fect of the cooler on the air passing therethrough ing the air conditioning chamber with the space, in accordance with the demand for cooling, individual means for circulating air through the whereby the dry bulb temperature of the air cooling and humidifying units, and individual passing through the humidi?er varies in accord means responsive to one or more psychometric ance with the temperature of the air in the con conditions within the space for controlling the ditioned space. operation of the individual circulating means. 16. The method recited in claim 15, and vary 23. The structure recited in claim 22, heat dis ing the rate of flow of the air through the cooler sipation means in heat exchange relation with in accordance with the demand for cooling and the humidifying unit, and means responsive to humidi?cation. 75 the diiference in dry bulb'temperature of the air 2,619,802 17 18 entering and leaving the humidifying unit for before and after such conditioning substantially controlling said heat dissipation means. constant, and pushing the other stream of air 24. In an air conditioning system the method to produce circulation in parallel with the ?rst of maintaining a space at a relative humidity stream of air and lowering its temperature after near saturation and a dry bulb temperature near such pushing to cause it to be substantially sat the freezing point of water, comprising passing urated. air from the space for return thereto through ’ WILLIAM O. KLINE. cooling and humidifying units in parallel, lower ing the dry bulb temperature of the air passing REFERENCES CITED through the cooling unit only slightly upon a 10 correspondingly slight rise in the dry bulb tem The following references are of record in the perature of the air in order to decrease the de ?le of this patent: humidi?cation of the air in passing through the cooling unit, and controlling the heat supplied UNITED STATES PATENTS to the humidifying unit so that substantially no 15 Number Name Date sensible heat is added to the air in passing 1,465,028 Stacey ______Aug. 14, 1923 through the humidifying unit. 1,662,806 Hilger ______Mar. 13, 1928 25. The method recited in claim 24 and con 1,882,030 Pennington ______Oct. 11, 1932 trolling the circulation of air through the cool 2,059,874 Jones ______Nov. 3, 1936 ing unit by temperature responsive means such 20 2,093,834 Gaugler ______Sept. 21, 1937 that the circulation is decreased when the need 2,135,285‘ Gibson ______Nov. 1, 1938 for cooling is substantially met. 2,168,157 Crago ______Aug. 1, 1939 26. The method of conditioning air for recir 2,188,526 Burden ______Jan. 30, 1940 culation into a space at which the relative hu 2,192,348 James ______Mar. 5, 1940 midity and temperature are maintained at near 25 2,268,769 Newton ______Jan. 6, 1942 saturation and close to the freezing point of wa 2,286,538 Guler ______June 16, 1942 ter, respectively, comprising dividing the air into 2,296,530 McGrath ______Sept. 22, 1942 parallel streams, moving one stream and raising 2,376,859 Benn ______May 29, 1945 its humidity while maintaining its temperature 2,419,119 Christensen ______Apr. 15, 1947