US2236480A - Evaporative cooling system for a humidified inclosure - Google Patents

Description

Patented' 25', 1941 Y o ,Umrap STATES vParri-:1er orrlca EvAroRA'rivE COOLING SYSTEM Fon A f HUMIDIFIED INcLosUnn vAlbert J. Loepsnger, Providence, B. I., assigner to i y' Y General 'Fire Extinguisher Company, Providence, R. I., a corporation of Delaware Application August 1i), 1938, Serial No. 225,779

. 7 Claims. (Cl. 98-33) This invention relates to an improved evaporaf be promptly restored and maintained regardless tive coolingl syst'er'n'- for a humidied inclosure. of the temperature, `In my co-pending application, Serial No. 15,811 Perhaps the most didicult conditions encoun-` fled `April 11.y 1935 and allowed July-14, 1938, and l tered are those pertaining when the outside air` now PatentNo. 2,128,096, lAugust 23, 1938 I have is at moderate temperature and its relative hu-y disclosed apparatus for controlling the cooling of midity isl high. Under such conditions a large such an inclosure and this application is a. convolume of outside air must be admitted and they l tinuation in part of that former application. -ehanges o1' air must occur frequently.A In cer- The presentinvennon is directed to the cooitain leXtJe rooms, for exemple. in a spinning l 10 ing of en inclosure in which the hnm'idifying` room Wherethe considerable horse power required `10 means are distributed throughout the inclosure maybe deemed t0 be almost entirely convert-,ed and. under suitable control', discharge moisture luto heat' @using unbeel'ebly high temperatures directly into the atmosphere of the room. Thus 1f not dlslpated 01 absorbed by Some cooling this invention l'is distinguished from what is com- Process elf Changes 0f the Order 0f `from fifteen .l5 morily known as a central station system in to twenty times an hour are required to produce l5 which che air forced into the inclosure is prethe' desired Cooling effect. The introduction of r this large amount of untreated outsid ir i r bein admitted to the atmos e av n Egiedgfelehg i g s uch a way as not to upset the desired'condi- In che texmeneid Epsrcicuierhr, che-maimetion 0f relative humidity for the material being nance of a desired'humdity condition of the air processed is not easily accompllshed- 20 y VThe haphazard air changes obtained from in a room or inclosure where the processing of textile materialls being carried on has long been opening windows While helpful Cannot Supply recognized as-'essentiaL i Various means havebeen enoiugh mirblto bdepress thi temperature as much developedandused for supplyingmoisture to the ai s pfflsl ti Y teVatDOra ve cooling. The most air, che commonest end most eireetive being the @cess d a emp S e Controlled air Changes have 25 atomization of water into extremely small pareet ma etheretofore with the use 0f large gradticles resembling a fog which is blown into .the y ua ed duc s ramifying about the inclosure and atmosphere of .the inclosure. The capacity of rlndissa'aeoggelto Vlll attosphel'e each *humidi'fymg mit is'relativ'ely Smau anda amount of-A al1Y introduced from eachesuci iriltllgtl:

considerable number 0f vSlllll units are scattered. can be readily moistened b nearb humidif n 30 throughout theSDaCe t0 be molstened-r on being means, there are nevertheless serlous praciicagl discharged into the 'air the Small droplets of W81' objections to a duct system. ter composingl- @he fog are evaporated Asthls As already pointed out, the amount of air to evaporationlnvelves a Change 0f physical Slate be handled is large, and the ducts must be large 3" from a liquidvto-a venom-the latent heat Yequlred also to keep velocities and friction loss within 3J is withdrawn froni ithe surrounding elf H- the limits set by good engineering practice. Such midification: alone thusy inherently also cauSeS a systemv is expensive to fabricate and install. cooling to an .el'feri dellendng uponthe amount and even when well designed necessitates a large of latentheat Withdrawn by "evlleletlol `fan which requires considerable power to" drive 40 Where the'peroentegeoi relative humidity iS it; The dimensions involved make the duct a. to be maintalrid-within a desired range. 0.1 et serious obstruction to the lighting system, and so'me predeteri'rii'tedfpel' Cent with allowable decrease the effectiveness v of the automatic slight toleranoesfitheretrom, it is obvious that the sprinklers by interfering with distribution of wecooling by eyaportloninllsll 4be SeCOUdrY t0 the ter discharge from them when a fire occurs. The 45 maintenance ,offlgii desired humidity Cerdltondisposal 'of lint and fly in textile mills is a trou- I! the evaportivO-I beoo'inesvso excessive that the `blesome '.problem which is further complicated desired relatieve humidityisexceeded, the hl'llmidi-y by the presence of a duct system. Accumulation fying 'means "are, rehdered inactivek by Suitable on the -top ofthe ducts is rapid, and must fre- COHtrOl apparatus. responsive 501615 te the huquently be removed, often necessitating shutting 50 midity. Ii, on .the other hand, the air .changes "down and covering machines ln the vicinity, The `are so frequent asto overtax the apeeity of the ducts are sorarranged at theintake end that humidifying means, lthe amount of 'fresh ,air adn. .on occasion air from the inclosure is mixed with mitte'dl to' utl'i`e`incl-osure, mustI befreduced so that f outside air and sometimes the air from the inin any eventthe desired'humidity;conditionshall closure alone is recirculated.- Under these cir- 55 cumstances deposits of lint and iiy accumulate inside the ducts where. removal is diiiicult and, moreover, constitute re hazards.

One of the objects of my invention is to eliminate the use of ducts and to provide a ductless system utilizing portions of the normal openings in the inclosure for the admission of large quantities of outside air. Another object is to provide for the immediate' mixing with the outside air of a greater or lesser proportion of the room air before the mixture is propelled into the room. And another and important object is to cause this mixture of primarily untreated air to be distributed in what I term the upper stratum of the inclosure so as to be generally available to all the humidifying yunits distributed about the inclosure.

In the case of a room where manufacturing is going on, the machinery and the operatives are in a stratum near the floor. In other rooms used for the humidity conditioning of goods, the

latter are usually in a similar lower stratum. It is the atmosphere of this stratum which must be maintained at the desired relative humidity for the best processing of where operatives and machinery are employed, it is this stratum which must be cooled because into it are liberated the heat units from the machinery which materially tend to increase 'the temperature near the operatives. customarily the humidifying apparatus is arrangedabove this lower stratum. Whether the units be humidifying heads or atomizing nozzles, or both, they are usually arranged to discharge the moisture into what I shall term an intermediate stratum.

The stratum above the humidifying means has heretofore for the most part been neglected andl not usefully employed in respect to air conditioning. Where forced air changes have not been provided, the air in this upper stratum has been relatively quiescent or stagnant. Even with duct systems, there is no attempt made to utilize the upper stratum as a whole fora sort of reservoir of untreated air generally available for all the humidifying means, or to bring about any one uniform movement of air throughout the upper stratum. It is a feature of my improved system to make definite use of this upper stratum and to so arrange the inlet and outlet openings that the air propelled into this upper stratum will traverse the entire inclosure.

The most economical way of moving large quantities of air against low resistance is by means of the propeller type fan. In employing such fans I preferably place them at inlet openings in certain walls ofthe inclosure with vents for exit remotely located from the inlets. Thus the air propelled by the fans must traverse the inclosure. Since the area available for intake is, however, limited, and since a large number of air changes are to be provided, the volume introduced at each opening must be great. It is a feature of the present invention to introduce this large amount of air in a concentrated area in such manner as to preserve the desired percentage of relative humidity in the lower stratum of the inclosure. This is accomplished by utilizing the upper stratum for the distribution of the air propelled by the fans. To that end I place the Uinlet apparatus, and, when necessary, provide directional varies, so that the large volume of incoming air will be directed into the upper stratum inlet Wall.

the material. Likewise` it travels through the upper stratum in a well defined jet, which, as it travels farther, spreads and loses velocity. This is true even where the location of a window may require the inlet opening to be rather low, in which case, the air leaving the inlet is directed upward and into the upper stratum and thus does not depress the relative humidity in the lower stratum adjacent the Because of this jetlike action and the slight pressure created by the fans theren is throughoutthe upper stratum a constant movement of air away from the fans towards the exit openings. The humidifying apparatus in the stratum below withdraws this fresh air either by direct fan action in the case of humidii'ying heads or by induced action in the case of atomizers. In the humidifying stratum the air near to the humidifying means is brought to a percentage of relative humidity much higher than that desired in the lower stratum, Vsome of it being saturated; During this process rapidv cooling takes place so that the super-humidified air sinks downward intothe lower stratum where it is mixed with air at a higher temperature and lower relative humidity to produce the percentage desired. There is thus in the lower stratum an up and down circulation, together with a gradual movement of the air as a whole towards the exit openings. Air in that portion oi' the lower stratum near to the fans is satisfactorily circulated by air currents induced by the rapidly moving incoming jets above.

A feature of my improved system in connection with the use of propeller fans is theprovision for mixing room air with outside air at the inlets. Air changes are required. almost throughout the year so that in certain seasons if thetemperlture of the outside airfalls below the dew point of the air inside, condensationwill occur as soon as the cold outside air mixes with the room air. This would appear asA a long jet of rather heavy fog issuing from the fans, 'a condition intolerable because the free moisture in this cold `iet would precipitate onto the machinery and work before it could evaporate. My system takes care of that difficulty by providing a thermostatic control which can be set to insure that the mix-- ture of outside air and inside air will always be above the dew point of the latter.

Other important features which characterize my improved system are the movement of a large volume of air at high velocity by the inlet apparatus, and the discharging of it directly into the atmosphere of the inclosure. Where the inlet apparatus can be located high enough in a window or other normal opening in a wall, the fan itself can be depended upon for the directional control of the iiow into the upper stratum, but it such normal opening is lower than desired, directional vanes are to be employed to insure that the air propelled by the fan shall be promptly directed toward the ceiling and thus into the upper stratum. There is thus set up a rather deilnite directed movement of the fresh air in the uppernot reach the lower moistened. The humidifying means, as before pointed out, draw air from the uppermoststravserved byl my improved system may be variously arranged, provided only that they lend themselves to the primary scheme of directional movement oi' the air through the several strata and in traversing the inclosure; charge outlets or exit means would preferably-be arranged in some wall of the inclosure other than that in whi'chth'e openings for the incoming air are provided but may be located when convenient in a monitor or otherwise in the roof of a building.

'I'he best mode in which AI have contemplated applying the principles of my invention are shown in the accompanying drawing but these are to be taken as merely illustrative because it is intended that the patent shall cover by' suitable expression in' the appended claims whatever features of patentable novelty exist/in the invention as a whole.

In the accompanying drawing the single figure` is a cross-sectional elevation cfa humidied inclosure with provision for evaporative cooling in accordance with the present invention.

Referring more particularly .to the drawing,

there is. shown a humidified inclosure having a tion ofthe atmosphere in the lower stratum and to keep the temperature thereof asxcomfortable as possible. Humidifying means are provided for introducing moisture into the atmosphere of the inclosure, such means being indicated -by humidifying head 5 and atomizlng nozzle 6, either or4 both of which may be employed.

The humidifying head li here shown has a vertical casing I with a fan 8 near its top opening which runs continuously drawing air inward and forcing it ,downward through the casing and outward into the atmosphere through a horizontal circular nozzle 9. Within the vertical casing is provided the usual water spray jet through which the air is forced to pick up and entrain globules of water. such a head is controlled bythe vshutting off or turning on of the water by means of a. valve l III which, as here shown, is vactuated by compressed air. The latter is received via a supply pipe II, which leads to any suitable control unit I2 from whence another air pipe I3 leads to the valve III.

The atomizing nozzle 6 is mounted on an air line I4 in which is a control valve I5 connected to piper I3 so that when the compressed air '1s` made available by the control unit I2 to open the water valve III and permit ow of water to the humidifying heads, the same air pressure willbe effective to open valve I5 and supply compressed air in the line I4 to cause an atomized vdischarge of water through the atomizing nozzle, which is also connected It0 a water pipe I6.

Thev humidifying means, whether of the head or nozzle type. or both, are located at a level above the stratum where the operatives are at Ordinarily, the dis-4 The humidifying action ofl work andthe machines and material in process are located or stored. -The air leaving the heads e orthenozzles is wellnigh saturated and thus there isv established inv the inclosure an intermediate horizontal stratum wherein the air thereof is highly moistened. To provide the desired humidity condition in the lower stratum, this highly moistened air must mix with the air f in the lower stratum. Thisordinarily presents noproblem because the' highly humidifled air is at about the temperature of saturation and falls to the lower stratum. Thus the mere object of maintaining a desired humidity condition for the processing of the material has readily been attained without difficulty for many years past.

the moisture can `be readily and continuously evaporated. AIn short, as the air in the lower lstratum becomes humidifled to the desired limit 2 of relative humidity, having thereby absorbed all the moisture it should and thus having provided the full cooling effect possible consistent with the maintenance of the desired humidity condition, this airshould move on, as it were, and be replaced -by new air capable of continuing the evaporative process forthe cooling influence.

'I This involves the admission of fresh and relatively unhumidied air to the inclosure, and the particular problem becomes Ione of proper dis-y tribution of this freshk air and the movement of all the air in the inclosure to maintain the condition of the air in the lower stratum as nearly uniform as possible. i

My improved system accomplishes thisin the following manner. In an ordinary opening of the room, such as a window I1 in the outside wall 2, there is arranged a casing I8 in which is suitably mounted a fan I9 and its driving motor 2U. 'I'his casing lhas two entrances 2I and 22. The entrance 2I is at the side exposed to the outside' air and the other entrance 22 is at the bottom exposed to the air vwithin the inclosure. These entrances or inlet openings are each provided with a series of interconnected louvers 23, 24 so arranged that as the outside louvers 23 are .opened the inside louvers 24 are closed and vice versa. Thus as air is drawn through theinlet entrances 2| and 22 by the fan I9, the proportion of fresh outside air to the air taken from within the inclosure may be regulated as desired. For example, a common modulating thermostatic device 25 can be arranged in the path of the air flow from the fan and be connected to a motor 26 so as to control the settings of the louvers 23, 24 to give a proportionate mixture of outside and inside air. It is important that this mixture,or the air propelled by the fan I9 shall have a temperature above the dew point of the room air. This will prevent' any formation of fog or precipitation of moisture which might occur if the temperature of the outside air should fall below the dew point of the inside air. Y

'Ihe casing I8 is located as near the top of the',

window or side wall of the closure as is possible and its discharge opening 2l is provided with a s et to direct the fan driven air very definitely upward toward the ceiling.

'Ihe volume of air moved by a fan I! is large and its velocity is relatively high, so that when initially directed upward toward the ceiling it tends to continue to flow along the upper stratum of the air substantially across the inclosure above the humidifying means. O f course, this initially rapidly moving current of air from the fan spreads out after it leaves the casing I8 and because of this, and the normal frictional resistance encountered by the air, the velocity of the air naturally tends to diminish. However, it is to be understood that both the initial volume and velocity must be sumcient, together with the slight pressure created,` to insure that the air propelled by the fan will move in the upper strata in a general direction toward a vent opening 29.

In the region of the lower stratum close by the inlet wall 2, there is no "dead-space" because when the louvers 24 are opened at all, a ilow of air from the lower stratum is induced by' the general iiow into the opening 22. And even when the latter is closed, the rapidly moving air discharged from the casing I3 sets up an induced ilow from the lower stratum generally upward along the inside of wall 2.

Although for purposes of illustration I have only shown one inlet opening, one outlet opening, and one of each of the characteristic humidifying means, it is to be understood that the latter are distributed throughout the inclosure and that additional inlet and outlet openings will be provided as needed.

The purpose of the directed airmovement in the upper stratum is to make available to the humldlfying means a source of relatively unhumidiiled air or air deficient in humidity, .which can be induced to flow into the heads or into :the induced currents formed by the nozzles 3, and continuouslypick up and entrain the moisture. As the air becomes molstened in the lintermediate stratum of highly humidied air it moves downward into the lower stratum. In the latter there is a continual movement of the air' due to several causes. One has already beenv noted being the movement 'of the molstened air`downward due to its low temperature, and the movement upward of this air after it has been heated in the lower stratum. Another influence is the in .ake of air into the casing i3 when the louvers 24 are opened to any degree. And finally there is the general ilow of the air towar'd the outlet openings 29. V

Where the inclosure being conditioned has opposite outside walls', it is highly desirable that the outlet openings for discharge of the room air be in the wall opposite that through which the fresh air is admitted. This preferred arrangement is seen in the ilgure where the outlet or discharge opening 2! is shown at the top of window 30 in wall 3. 'This particular location of the exit means is preferred because it is at the end, or4 possibly beyond the end, of the directed movement of the air in the upper stratum. Being at the top of the window any localized drafts set up by the out' going tlow are not felt by the operativesv working near the wall 3 in the lower stratum of the air. There is merely a sort of lazy travel or movement of the air more or less horizontally along the lower stratum with a gradual turning ipward and outward as the moving air approaches the wall 3. Where, however, it is not possible or convenient to locate the exit openings in an opposite wall they may be provided at any remote location from the inlet favorable to the general directional travel ot theA air above mentioned.

ample the motor 23 connected to the louvers 23 24 might be actuated by a control unit 3| in response to either or both the humidity or tem-` perature conditions of the room air and beeiYective to vary the setting of the louvers... 'Mera-,l

over, in the event that it is desired ty prevent any entry of outside air when theV temperature 4within the inclosure reaches some predetermined mini--` mum degree, a thermostatic device 32 may be `provided which assumes control upon such temperature being reached and efl'ects the closure oi.' the louvers 23 so long as the temperature in the lower stratum is ator below the permissible minimum.

By myV improved method oi directing the now of an appreciable volume of air admitted from the,

outside, or a mixture of outside air with the inside air of an inclosure, and providing for a generally directed movement oi' this .air through the upper stratum, a likewise generally directed induced ilow of this air int'o a stratum of highly humidied air, and a further generally directed flow of the `highly humidiiied air into'the lower stratum, a substantially uniform condition of de-V sired relative humidity and comfortable temperature is maintained. Andfto repeat, this substantially uniform distribution of humidity in the lower stratum and the desired comfortable temperature thereof is effected by my improved system without using any ducts whatever.

l. An evaporative cooling system for a humidiiled inclosure having a lower stratum to be cooled and maintained at a desired relative humidity: humidifying means distributed about the inclosure in an intermediate stratum above said lower stratum; means adjacent a wall for drawing in outside air and propelling it directly into the atmosphere of the inclosure in an upper stratum above said intermediate stratum in sufficient quantity and with sufficient velocity to be substantially uniformlyavailable to the humidif'ying means distributed about the intermediate stratum; and exit means for discharge of air from the inclosure located remote from said air propelling means; the said humidifying means acting to move air from said upper stratum into said intermediate stratumand there to highly humidify and cool the air, whereby said highly huxnidiiied and cooled air descends from the intermediate stratum into the lower stratum and reduces the temperature of and establishes the desired condition of relative humidity in the air of said lower stratum, there being a general movement of air throughout the inclosure from said air propelling means to said remote exit means.

2. An evaporative cooling system for a humidiiled inclosure having a lower stratum to be cooled and maintained at a desired relative humidity; humidifying means distributed about the inclosure in an intermediate stratum above said lower stratum; means for propelling air directly into the atmosphere of the inclosure in an upper stratum above said intermediate stratum comprising a casing adjacent a wall of the inclosure having an opening through which outside air is admitted, an opening through which inside air is admitted and a discharge opening through which the mixture oi' the two airs' is propelled into the upper stratum in sufficient quantity and with simicient velocity to be available to the humidifying means distributed about the intermediate stratum; and exit means for discharge of air from the inclosure located remoteirom said air propelling means; the said humidifying means acting to move air from said upper stratum into said intermediate stratum and there to highly humidify and cool humidiiied and cooled air descends from the intermediate stratum into the lower stratumand reduces the temperature of and establishes the desired condition of relative humidity in the air of said lower stratum, there being a general movement of air throughout the inclosure from said air propelling means to said remote exit means.

3. An evaporative cooling system for an inclosure having a lower stratum oi air adjacent tov the iloor in which a desired relative humidity is to be maintained, humidifying means distributed about the inclosure above said lower stratum and within an intermediate stratum within which latter stratum the 'relative humidity is in excess of said desired relative humidity; an opening in an outside wall of the enclosure with air moving means adjacent said opening for drawing in outside air and discharging it directly into said upper stratum; and exit means remote from said air moving means so arranged that the air discharged into said upper stratum traverses the extent thereof in a general direction from said air mov-r ing means toward said exit means, thereby making available to all the humidiiying means the air of said low relative humidity; ing means acting to draw the air from the upper stratum into said intermediate stratum and there to humidity it in excess of said desired relative humidity whereby the air is materially cooled, whence said excessively humidiiled and cooled air descends into the lower stratum there to establish the desired condition of relative humidity while reducing the temperature of said lower stratum.

4. An evaporative cooling system for a humidied inclosure in which it is desired to cool the air of a lower stratum adjacent the iloor while maintaining the relative humidity of the air in said stratum substantially uniform, which system comprises, in combinatio'n, htunidii'ying means distributed about the inclosure and located in an intermediate stratum of air just above the said lower stratum, an inlet opening in' an outside wall y of said inclosure with means4 adjacent said inlet opening for 'drawing in .outside air and propelling it directly into an upper stratum of air above said intermediate stratum, and air exit means located in the inclosure remote from said propeiling means; the said propelling means being constructed and arranged to effect distribution oi said outside air throughout the said upper stratum wherefrom said air is drawn downward into the intermediate stratum by the action of the humidifying means and highly humidiiied and descends thence into the lower stratum there'to accomplish the desired cooling and maintenance of the relative humidity.

5. An evaporative cooling system for a humidifled inclosure having a lower stratum in which heat primarily liberated from operating machinery tends to maintain an excessive temperature and in which stratum it is desired to cool the air while maintaining it at a desired condition of relative humidity, which system comprises an inlet opening in an outside wall o! the inthe air, whereby said highly the said humidifyclosure with means adjacent thereto for drawing in air and propelling it directly into an upper stratum of the inclosure; humidifying means dis. tributed about said inclosure in an intermediate stratum between said upper and lower strata.; and air exit means located in said inclosure remote from said propelling means: the said humidifying means'acting to cause movement of the air from said upper stratum into said intermediate stratum and there to highly humidity the air and cool it to a temperature materially below that of the lower stratum, whence such highly humidified and cooled air descends into the lower stratum and encounters the liberated heat whereby there is produced the desired condition of relative humidity at a ytemperature below that which would otherwise be effected by said heat liberation. s

6. An evaporative cooling system for a humidified inclosure in which it is desired to cool the air in a lower stratum adjacent the oor while maintaining the relative humidity of the air in said stratum substantially uniform, which system comprises humidifying means distributed about the inclosure and located in an intermediate stratum of air just above the said lower stratum, anvinlet opening in an outside wall of said inclosure with means adjacent said inlet opening for effecting a mixture of outside air with air taken from the inclosure, means for propelling said mixture `directly into an upper stratum of air above said intermediate stratum, control means responsive to changes oi an air condition within the inclosure for regulating the proportion of outside air and inside making up said mixture, and an exit opening from said inclosure remote from said propelling means; the said propelling means and exit opening being constructed and arranged to eilect distribution of said drawn-in air throughout the said upper stratum wherefrom said air may pass into the intermediate stratum and be highly humidied and thence descend into the lower stratum to accomplish the desired cooling and maintenance of the relative humidity.

7. An evaporative cooling system for a humidiiied inclosure in which it is desired to cool the air in a lower stratum adjacent the iloor while maintaining the relative humidity of the air in said stratum substantially uniform, which system comprises, in combination, an inlet opening in an outside wall of said inclosure, means adjacent to said opening for drawing in outside air and propelling it directly into an upper stratum of air adjacent the top of said inclosure, a series of humidliying units distributed about the inclosure in an intermediate stratum of air between the said lower and upper strata, and exit means for discharge of air from the inclosure located remote from said inlet opening; the aforesaid propelling means being constructed and arranged to eifect a general distribution of the outside air through the said upper stratum, wherefrom the air is drawn downward by the action of the humidiiying units into the said intermediate stratum and there highly humidied, whence said highly humidliled air passes into the said lower stratum to effect the desired cooling and the maintenance of a substantially uniform relative humidity condition therein, there being a con' tinuous-movement of air generally from the inlet opening toward the said remote exit means.

ALBERT J. LOEPSINGm.

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