US2205716A - Unit heater and air conditioner - Google Patents

Description

J1me 1940. c. A. DUNHAM ET AL. 3 9

QNIT HEATER AND AIR CONDITIONER Filed Feb. 4, 1938 7 Sheets-Sheet l June 25, 940- c. A. DUNK-1AM El AL .UNIT HEATER AND AIR CONDITIONER Filed Feb. 4. 1938 '7 Sheets-Sheet 2 14M a? $025.3 [hos/11m??? C. A. DUNHAM ET AL UNIT HEATER AND AIR CONDITIONER Filed Feb. 4, 1938 7 Sheets-Sheet 3 June 25, 1 I

c. A. DUNHAM ET AL 205,316

UNIT HEATER AND AIR CONDITIONER Filed Feb. 4, 1938 7 Sheets-Sheet 4 i293 P 24' 4; 4a? 50 Ira/e nfo n Chg Z522 14.510050? June 25, 1'1 a. A. DUNIHAM Er AL UNIT HEATER AND AIR CONDITIONER Filed Feb. 4, 1938 7 Sheets-Sheet 5 a f Aj ZZ a fia fioslzmzjffi V; ig orme ys.

C. A. DUNHAM ET AL UNIT HEATER AND AIR CONDITIONER 7 Sheets-Sheet 6 Filed Feb. 4, 1938 Z Aim/5 W 45 June 25, 1940. c. A. DUNHAM ET AL 'UNI'I' HEATER AND AIR CONDITIONER Filed Feb. 4, 1938 7 Sheets-Sheet 7 UNIT HEATER AND AIR COITIONER Clayton A. Dunham, Glencoe, and David N. @rosthwait, Jr., Chicago, Ill., assignors to C. A. lllunham Company, Marshalltown, Iowa, a corporation of Iowa Application February 4, 1938, Serial No. 188,598

1 Claim.

This invention relates to certain new and use- !ul improvements in an air-conditioner unit adapted to be positioned similarly to an ordinary radiator within a room, and designed to either heat or cool the air within a room, humidify the air, and ventilate the space by introducing a desired proportion of freshair.

This unit is designed to form part of a suitable heating or cooling system which supplies the unit with the heat-transfer fiuid medium, for example steam in winter and cold water in summer. It is well known that, on the average, about three times as much heat transfer surface is required to adequately cool the air when the cooling medium used is within the range of 40 to 50 Fahrenheit, as is required to heat the same space with steam in the temperate zone. A suitable radiator or heat-transfer device is provided which automatically provides for this change in heat-transfer surface as the temperature requirements vary.

Briefly described, the novel unit comprises a suitable hollow metallic casing having a louvered outlet opening in the top, and a similar inlet opening in the lower portion of the front wall. A second inlet opening in the lower portion of the rear wall connects with a conduit for introducing fresh outside air. The casing comprises a removable top member, and a front and end wall unit that may be detached from the back wall and removed after the top has been lifted off. The main supporting portion of the frame structure comprises the rear wall and a pair of vertical forwardly extending partitions that are spaced somewhat from the respective ends of the rear wall. Within the air-treating space between these partitions is housed at the top the heating or cooling radiator and the humidifier, and at the bottom, above the inlet openings, extends a suitable filter through which the inflowing air must pass. Between the filter and the heating and cooling unit is positioned a suitable blowing mechanism which creates the circulation of air upwardly through the housing. An adjustable damper mounted beneath the filter and between the two inlet openings determines the relative proportions of the fresh and re-clrculated air which are drawn upwardly through the filter and treated by the tempering and humidifying mechanism. The supply and return piping, valves, and regulating and adjusting mechanisms are positioned in the end spaces beyond the partitions and between these partitions and the removable end walls.

The principal object of this invention is to pro- (Cll. 257-137) vide an improved air-conditioner unit of the type briefly described hereinabove and disclosed more in detail in the specifications which follow.

Another object is to provide an improved radiator or heat-exchange unit, the effective capacity of which is suitably and automatically varied in accordance with the use of heating or cooling medium therein.

Another object is to provide an improved humidifier adapted to be used in connection with the heat exchanger so that the temperature of the water is automatically controlled.

Another object is to provide an improved blower assembly for properly directing the air stream or streams toward all portions of the heat exchanger.

Another object is to provide an improved means for supporting and cushioning the blower assembly.

Another object is to provide auxiliary draft openings for automatically permitting a free air circulation upward through the casing when the blower is not in operation.

Another object is to provide an improved form of adjustable damper mechanism for proportioning the amounts of fresh and re-circulated air introduced into the conditioning unit.

Another object is to provide an improved form of casing having readily detachable parts for enclosing the tempering and air-circulating mechanism and providing ready access thereto.

Another object is to provide an improved louver, construction for use in a casing of the above type.

Another object is to provide an improved inlet valve for adjustably regulating the fiow of either cooling or heating medium to the heat-exchanger.

Other objects and advantages of this invention will be more apparent from the following detailed description of certain approved forms of mechanisms constructed and operating according to the principles of this invention.

In the accompanying drawings:

Fig. 1 is a front perspective view of the assembled unit with the enclosing housing in position.

Fig. 2 is asimilar perspective view but looking at the housing from the rear.

Fig. 3 is a larger perspective view of the front of the assembly with the front, end and top walls removed.

Fig. 4 is a plan view of the assembly, with a central portion broken away, and the top or cover removed.

Fig. 5 is a detail view of one of the latching assemblies for holding the end walls to the rear wall.

Fig. 6 is a perspective view of one of the latch members.

Fig. 7 is a detail view of one of the louver assemblies.

Fig. 8 is a detail view showing how one of the slats or louvers is secured in position.

Fig. 9 is a transverse vertical section, on a larger scale, taken substantially on the line 9-9 of Fig. 3.

Fig. 10 is an enlarged detail section, taken on substantially the same plane as Fig. 9 through the humidifier, but showing the cover in partially elevated position.

Fig. 11 is a transverse vertical section taken substantially on the line II-II of Fig. 3.

Fig. 12 is a detail longitudinal vertical section taken substantially on the line l2-I2 of Fig. 11.

Fig. 13 is an enlarged vertical section through the radiator or heat exchanger, with the greater portion of the center of the assembly broken away.

Fig. 14 is a horizontal section through one end portion of this heat exchanger, the view being taken substantially on the line I4-I4 of Fig. 13.

Fig. 15 is a detail longitudinal vertical section through one of the blowers, the view being taken substantially on the line l5l5 of Fig. 9.

Fig. 16 is a detail elevation of the worm gearing for adjusting the damper.

Fig. 17 is a longitudinal vertical section through the blower-supporting panel showing the auxiliary draft doors in the panel.

Fig. 18 is a vertical central section through the inlet valve, the view being taken substantially on line l8l8 of Fig. 19.

Fig. 19 is a plan view of the valve.

Fig. 20 is a detail vertical section taken substantially on the line 2020 of Fig. 2.

The assembly comprises in general the enclosing casing or housing A, the heat-exchanger unit B, the humidifier C, the blower assembly D for enforcing the air circulation through the housing, the filter E, the adjustable damper mechanism F, and the improved inlet valve G.

The frame A which is formed of sheet metal parts comprises an upright rear wall I having inturned flanges 2 and 3 at its respective ends and also similar inturned flanges along parts of the top and bottom. Forwardly extending vertical partitions 4 and 5, also formed with flanges along their several edges, are secured to the rear wall I along lines spaced inwardly from the ends of the rear wall so as to provide a space between the partitions in which the greater portion of the air circulating and tempering mechanism is mounted. These features are for the greater part supported on these partitions, as hereinafter described. The partitions 4 and 5 extend above the rear-wall I, as clearly shown in Figs. 3 and 20, and support the removable top or cover mem ber as hereinafter described. The end spaces beyond the partitions 4 and 5, and between these partitions and the outer end walls, are adapted to house the piping, valves, adjusting mechanism, etc., as hereinafter referred to. The supply piping will ordinarily go out through the open bottom of the casing, but openings 6 and I are provided in'the lower portion of rear wall I communicating with the end spaces so that these pipes may be extended laterally outward through an adjacent wall of the building. An inlet .air opening 8 is also formed in the lower portion of rear wall I and communicating with the space between the partitions 4 and 5. Inturned flanges 9 integral with rear wall I are formed around the sides and ends of the opening 8 and a rectangular frame I9 is secured to these flanges within the opening (see Fig. 9). The end of any suitable conduit II can be connected with this frame III, the conduit ll extending through an adjacent wall and communicating with the outer air so that fresh air can be drawn ilithIOilgh the inlet 8. If thefresh air inlet is not to be used, a suitable closure can be fitted in or on flanges 9 so as to block up the opening 8.

The front wall I2 is rounded at the ends I3 and has end walls I4 formed integrally therewith, the end walls I4 being bent parallel to the rear wall I at I5 and terminating in inwardly extending flanges l6 (see Fig. 4) which are adapted to fit against and parallel to the end flanges 2 on the rear wall.

Pivoted on one of each pair of flanges 2 and I6 are a pair of similar latch members I1 (see Figs. 4, 5 and 6). These latches are disposed near the top and bottom of the casing respectively. Each latch is pivoted at its lower end I8 so as to swing inwardly, and when swung up to operative position the yoke I9 at the upper end of the latch member is adapted to engage over the mating flanges 2 and I6 and lock same together. An upright operating rod 20 is pivoted at 2| and 22 to the two latches and is provided at its upper end with a handle 23 which is accessible to operate the latches when the cover 24 of the casing is removed.

A bottom frame member 25 is suitably secured to the partitions 4 and 5 and is provided with an upstanding flange 26 along the front of the assembly between the partitions.

A second inlet opening 21 for i e-circulated air is provided in the lower portion of front Wall I2 so as to be substantially opposed to the inlet opening 8 in the rear wall. Inturned horizontal flanges 28 and vertical flanges 29 are formed around the sides and ends of the opening 21. The lower flange 28 rests on the upright flange 26 of the bottom member, and an angular strip 28' (see Fig. 9) is secured to the under side of flange 28 so as to lock the front wall to the bottom flange 26 when the front and end wall assembly is pushed inwardly and downwardly into position.

The inturned end flanges 29 are provided with a plurality of parallel slots 30, preferably arranged at an angle to the horizontal, and in these slots are secured the ends of theslats or louvers 3|. Preferably these louvers are notched at their ends as indicated at 32 (Fig. 8) so that the outer edges of the louvers will be substantially flush with the outer face of the casing, and the end portions of the louvers project through the slots and are Welded to the flanges 29 as indicated at 33. A

Preferably ornamental strips or ribs 34 are secured horizontally around the lower portion of thefront and ends, and a similar strip 35 is secured around the lower edge of the cover 24. An' inner metal strip 36 is welded to the outer face of the wall member l2 or I4, and the bowed outer ornamental strip 34 or 35 (preferably formed of some bright or highly polished ornamental metal) is snapped into place or pushed endwise onto this inner holding strip 36 (see Figs. 9 and 10) In this manner the ornamental strips are firmly but removably mounted so that any ordinary accidental impacts will not result in jarring the strips loose.

The removable cover member 24 fits over the upwardly extending end portions of partitions 4 and 5 and rests on the felt strips 24 carried by these partitions, and is provided with short downwardly extending front and rear walls 31 and 38 and end walls 39 adapted to match with and form extensions of the similar walls of the main housing. The lower edge of the front wall 37 of the cover is provided with an inturned flange 4|] and the ornamental rib 35 is so secured to the front and end walls of the cover as to project downwardly over the main front and end walls. An angular strip 4| having an upturned inner flange 42 is secured to the under face of flange l1, and the flange 40 is adapted to bear against flange 42 so as to press this flange against cushioning strip 42 carried by the frame member 42 mounted at its ends to vertical partitions 4 and 5.

The main end walls l4 and the end walls39 of the cover are provided with inturned flanges l4 and 39, respectively, and a latch member ll of the type shown in Fig. 6 is pivoted on each flange l4 and may be swung to the position shown in Fig. 20 to lock the cover in place.

An upper outlet opening 43 is formed in the top of cover 24. This opening may be louvered and formed in all respects the same as the opening 21! in the front wall as already described. Access openings are formed in the end portions of cover 24 above the end spaces beyond the partitions 4 and 5, these openings being normally closed by pivoted doors 44. Each of these doors is pivoted on an axis 45 spaced somewhat from one edge thereof and a torsion spring 46 secured about this axis serves to normally hold the door closed against a stop 41. on the short extension 48 at one side of pivot 45 the door may be swung to open position thus giving access to the latches I1 and to certain other mechanisms in the end spaces. After the latches H are released the cover 24 can be bodily removed so as to expose the mechanism as shown in Fig. 4. To provide additional access to the parts the latches H can be unlocked and the front and end walls removed so as to expose the entire assembly as shown in Fig. 3.

The improved heat-exchanger B is built up from a plurality of thin metal tubes 49 mounted at their ends in suitable headers and provided with a plurality of thin metallic fins 50 and 5| to increase the radiating or heat-exchange surface. While the number and arrangement of these tubes 49 could be varied, in the example here shown these tubes are arranged in three substantially horizontal tiers of five tubes each, the tubes of each successive tier being staggered so as to be positioned beneath the spaces between tubes of the adjacent tiers thus providing a maximum surface contact with the upwardly flowing air. The heating or cooling medium is introduced into one end of the tubes of the upper tier, and thence flows alternately back and forth through the successive tiers. For this reason the successive tiers are inclined slightly from the horizontal to facilitate drainage.

The fluid heating or cooling medium is introduced through inlet pipe 52 .provided with inlet control valve 53 (a preferred form of which is hereinafter described more in detail) into the header 54 (Figs. 13 and 14) into which is connected one end of each of the upper tiers of tubes 49. An internal web 55 (which may be provided By simply pushing in with openings 55'.) serves to equalize the distribution between the several tubes 49. It will be noted that in the example here shown the tubes 49 are of 'oval cross-section with the greatest diameter positioned vertically.

At opposite ends of the heat-exchanger the upper and next lower tiers of tubes 49 are connected by the header 56 divided by an internal web 51 having a port 58 adapted to be closed by a movable valve member 59 carried by the thermostatic disk 60. This functions the same as the usual thermostatic-trap so that when steam is used as a heating medium and the chamber 5i becomes filled with steam disk 60 will expand and cause valve member 59 to close the port 58. -In this manner, when steam is used as a heating medium the steam is confined to the uppermost tier of tubes 49. When condensate accumulates in chamber 6! the trap will open and permit this condensate to drain out through port 58.

The intermediate and lower tiers of tubes are connected at the opposite end by the header 62 (it will be noted that thereis no connection between headers 54 and 62) while at the other end the lower tier of tubes drains into a header 53 from which directly extends the return or drain pipe 64.

It will be noted that when steam is used as a heating medium only the upper tier of tubes is filled with steam, but the condensate must drain through the two lower tiers on its way to the drain pipe 64, and thus these lower tiers will act as an economizer to extract the maximum quantity of heat from the hot water.

Although separate fins on each pipe, or each tier of pipes, could obviously be used, it will be noted that as here shown continuous fins 50 are mounted on both the upper and intermediate tiers of pipes. In this manner the fins of the intermediate tier serve as additional radiating surface for the upper steam-filled pipes. These fins 50 are intermediately crimped or bowed as indicated at 65 in Fig. 13 thereby permitting the two series of pipes 49 to be inclined somewhat with relation to one another for drainage purposes.

The intermediate bowed portions 65 of the fins also serve to impede the progress of the upwardly flowing air and thus provide for greater heattransfer. The second series of fins 5| are mounted only on the lower tier of pipes 49. Obviously this arrangement of the radiating fins could be varied as desired.

When the heat-exchanger is used for cooling purposes and cold water is passed through the pipes or conduits, the trap 50 will remain open and the cold water will flow continuously through all three tiers of pipes so that all portions of the heat-exchanger will be equally effective. This is essential since greater heat-exchange surface is necessary during the cooling season since the temperature of the cooling medium does not differ as greatly from the prevailing air temperature as does steam during the heating season.

It will be noted that the heating or cooling medium and the air flow in opposite directions, that is the upwardly flowing air stream encounters the lower cooler pipes (during the heating season) and encounters the upper hotter pipes after the air has been somewhat preheated. This is the most effective system for heat-exchange. The same is true, with a reversal of temperatures, during the cooling season.

In summer, when the apparatus is used for cooling purposes, moisture will precipitate out iii as to collect this moisture.

face.

of the air incidental to the cooling process and for the purpose of collecting this moisture a plurality of V-shaped troughs 61 (Figs. 9 and 11) are arranged beneath the heat-exchanger B so These troughs are arranged in two tiers, staggered with relation to each other, so as to not interfere with the upward flow of air through the casing but at the same time provide a continuous collecting sur- These troughs are supported at their respective ends on the partitions 4 and 5 and are inclined somewhat toward one end (Fig. 11) where the troughs discharge into a receptacle 68 from which extends a drain pipe 69.

15 The humidifierC comprises a tank 10 (Fig.

10) which is secured closely adjacent the heatexchanger B so that the body of water H in the humidifying tank will be heated from the heat exchanger. The body of water 'H is maintained at substantially constant level by the introduction of Water from a supply pipe 12 (Fig. 3) through valve 13 automatically controlled by float 14, in well known manner. A heating coil consisting of a plurality of pipes 15 is positioned in tank 70, the inlet end of this coil being supplied with steam from the main inlet pipe 52 through a branch pipe 16 provided with a control valve 11. The coil 15 discharges at its other end through pipe 18 and steam-trap 18' into the main drain pipe 64. An intermediate partition or bafiie 19 positioned in tank 70 causes a convection circulation of the water so as to equalize the temperature at the surface of pool ll. The tank 10 is preferably metallic so as to readily transmit heat from the heat exchanger B, and is open at its top.

An upwardly extending air passage 88 is formed between the front Wall of tank 18 and a baflie member 8! suitably mounted on the upper frame member 42*. A closure member 82 pivoted at 83 is adapted to close the top of passage 80 and tank 18 as shown in Fig. 9, in which case no air flows through the passage 80 and the humidifier is ineffective. An adjusting screw 84 has a universal central connection 85 with cover 92 and a universal connection 86 with tank 10, and by means of this adjusting screw 84 the cover 82 can be raised to any desired position so as to permit a restricted flow of air through passage 88, then in contact with the surface of the heated pool of water H, and thence through the upper portion of the heat exchanger and out through outlet 43, all as indicated by the arrows in Fig. 10. By thus permitting a portion of the air stream to flow in contact with the water supply in the humidifier, a desired proportion of watery vapor can be added to the main air stream.

It will be noted that when this humidifying device is used in connection with a differential heating system, that is one that is varied in accordance with outside temperature changes, it will be automatically set so as to maintain substantially uniform inside humidity. With a 05 constant quantity of fresh air admitted and with the temperature of the heating coil varying directly with the weather conditions, the rate of heat transfer from the heating coil to the water is in substantially direct proportion to the temperature of the outside air so that with the humidifier construction as shown the rate of vaporization of water will be inversely proportional to the temperature of the outside air which is the same as being inversely proportional to the 3 weight of moisture in the air initially so that in extreme weather greater quantities of moisture will be added and in milder weather lesser quan: tities, thus insuring the maintenance of the desired humidity. Since the cubical air contents of the room to be supplied with air by this airconditioner will vary in practice, the position of cover 82 can be adjusted by means of screw 84 so as to obtain the desired humidity adjustment in accordance with the capacity of the room. When once adjusted this adjustment will not ordinarily have to be changed for any particular installation of the unit.

I The filter 151- (see Figs. 3, 9 and 12) is of rectangular form and comprises the filtering material 81 enclosed between a pair of wire screens 88 and held in an outer metallic frame 89. The frame 89 is adapted to be slipped laterally into position in a pair of metallic brackets 98 mount ed on the partitions 4 and 5. When in position the side edge portions of the filter will rest on the inturned flanges 28 and 9 respectively of the front and back walls so that all of the air drawn into the casing through inlets 21 and 8 must pass upwardly through filter E.

The damper F determines the proportions of fresh and re-circulated air that are drawn into the housing. This damper F (see Figs. 3, 9, 11 and 12) is pivotally mounted at its lower edge on a shaft 9| mounted in partitions 4 and 5 near the bottom of the casing. The damper is of rectangular form but is telescopic so as to be of variable width, being composed of a hollow lower member 92 into which telescopes the fiat upper member 93. Each of these members may be provided with strengthening ribs as indicated at 94. The damper is made telescopic so that the upper edge of member 93 may be maintained closely adjacent the lower surface of filter E in all positions of the damper. The upper damper member 93 is supported near its upper outer corners by brackets 95 carrying rollers 96 movable in trackways 91 mounted on the partitions 4 and 5 substantially parallel to the position of filter E. Preferably each roller 96 is of the type provided with an interior series of ball bearings 98 as indicated in Fig. 11 so that free rolling movement of the support is possible with the application of very little effort to the supporting shaft 9|.

Any suitable means may be provided for adjusting the position of the damper. As here shown shaft 9| is provided at one end with a worm wheel 99 meshing with a worm Hill on the lower end of a vertically extending adjusting shaft llll. Shaft Hll is provided at its upper end with a handle I82 by means of which the shaft may be manually rotated so as to suitably position the damper F. It will be understood that the damper might be motor-operated if so desired.

It will be seen that with the damper in the extreme forward position indicated in Fig. 9 only fresh air will be admitted to the unit through the rear inlet 8. If the damper is adjusted to its other extreme position only re-circulated air will be admitted through the front inlet 21. If the damper is in some intermediate position such as shown in Fig. 11, the air stream flowing through the unit will consist of desired proportions of fresh and re-circulated air.

It will also be noted that should a strong wind or draft tend to blow through the lower portion of the casing, this air will be deflected upwardly by damper F and consequently cannot chill the feet of occupants of the room.

A stop screw I03 may be provided (Fig. 11) to prevent the roller 96 from leaving its guide, and felt strips I04 mounted on the end partitions 4 and 5 may be provided to prevent fresh air from leaking past the damper when in ex treme rear position.

The blower assembly indicated generally at D is positioned in the chamber between filter E and the upper heat exchange and humidifying units. This assembly comprises a pair of spaced apart similar centrifugal fans or blowers I05 and I05, and an intermediate driving motor I66. This assembly is supported by the rectangular panel I01 carried at its ends on the vibrationdampers or cushions I08 (Fig. 11). These cushions comprise inner parts I09 bolted at H to the panel I01, and outer members III mounted on the brackets H2 (Fig. 3) secured on the partitions 4 and 5. The rubber cushions H3 are vulcanized between the members I09 and III so that the load will be taken up by a shearing stress on the rubber.- In this manner the resilience is kept at a maximum and vib rations are minimized. It will be understood that motor I06 is suspended in suitable cushioned supports from the bottom of the central portion of panel I0'I.

Each blower I05 or I05 (see Figs. 9 and comprises an inner cage structure II 4 comprising a series of curved vanes H5 carried by disk H6 and mounted on one end of motor shaft Hi. This cage rotates within a drum-shaped housing H8 which has a peripheral spiral form, that increases somewhat in diameter in the direction of rotation of the cage H4. The ends H9 of the housing are provided with central inlets I20, preferably curved inwardly at their edges, and the air stream is expelled through an outlet I2I in the top of housing I I8 and extending through panel I0'I. A pair of similar'deflectors or baliles I22 are positioned within housing II8 so as to partially surround the rotating cage as shown in Figs. 9 and 15. These baffles are spaced inwardly from the end walls H9 of the housing and diverge from one another in an upward direction so that the air projected upwardly through outlet I2I by the centrifugal blower will be spread fanwise as it flows upwardly toward the heat exchanger. In this way the air streams projected upwardly by the two blowers will be distributed over those portions of the heat-exchanger above the motor and the space intermediate the two blowers, as well as the spaces beyond the ends of the blowers. The motor I06 is preferably of the three-speed or multi-speed type and is conveniently controlled by switch I23 (Fig. 4) accessible through one of the doors 44 in the top closure.

It will be noted that strips of sponge rubber or felt I24 (Figs. 9 and 11) are positioned around the supporting panel IM to minimize vibration and seal this outer space, and similar dampening strips are used at various other locations in the unit.

It is desirable at certain times, particularly during the heating season, to operate this device without the use of the blowing mechanism, that is rely upon natural draft to cause the upward flow of air through the casing and in contact with the heat-exchanger B. Under certain conditions this method of operation will be satisfactory, slightly more economical, and will be somewhat more noiseless due to the fact that the fans or blowers are not in operation. The free flow of air upwardly through the casing may be somewhat facilitated by removing the filter E which may be withdrawn laterally from its supporting frames 90. I

To facilitate a free flow of air through panel I0'I when the blowers are not in operation, auxiliary passages I25 are provided through the floor of the panel between the blowers and beyond the ends thereof. These passages I25 (Fig. 1'7) are provided with closures I26 pivoted somewhat offcenter at I21 so that the arm of the closure which swings upwardly will be of greater area than the arm which swings downwardly. Small torsion springs I28 may be provided to normally swing these closures to the upwardly sloping open positions shown in Fig. 17, and this is the position that the closures will assume when the blowers are not in operation. When the blowers are operating a higher pressure will be created above the panel I01, and this pressure exerted on the larger upwardly extending portions of the closures will swing them to a substantially horizontal closed position so as to cut off the flow of air through passages I25. As soon as the blowers cease to operate these closures I26 will auto matically swing open and permit the free flow of 7 air through passages I25 in addition to the circulation through the blower passages I2I.

A preferred form of inlet valve G is shown in Figs. 18 and 19. This valve comprises a casing I29 having an internal web I30 provided with an upper .valve seat I3I and an internal passage I32. When the valve is open the heating or cooling medium will flow in through the lower inlet I33 and out through side outlet I34 to the heat exchanger. A movable valve member I35 is adapted to engage valve seat I3I to close the valve. The valve member.I35 is raised or lowered by stem I36 connected with nut I3! engaging in an internal nut I38 rotated by handle I39. A continuous sealing diaphragm I40 connected at its lower end to the movable valve member I35 and at its upper end to the valve casing tends to prevent the escape of steam or other medium through the upper end of the valve casing. The valve as thus far described is well known in the art.

To the bottom of movable valve member I35 is affixed a cylindrical sleeve I4I adapted to fit slidably within the valve port or passage I32. The upper cylindrical portion of this sleeve is formed with a plurality of downwardly diverging tapered slots I42 so that as valve member I35 is raised from its seat these slots will be successively uncovered to a greater extent thus providing a gradually increased flow of fluid through the valve. When the sleeve is raised to the extreme position shown in Fig. 18, only the small guide strips I43 remain in passage E32 and the flow of steam through the passage is substantially unobstructed.

The upper rotatable operating portion of the valve is provided with a pointer I44 movable over the dial I45 fixed to the upper portion of the valve casing. When the valve is in completely closed position the pointer will be at substantially the location indicated at I46. As handle I39 is swung in a counterclockwise direction (Fig. 19) the pointer will pass successively over the por tion of the dial calibrated in gallons per minute. This indicates the flow of cooling liquid through the valve. For example when the pointer is at the numeral 2, the slots M2 in sleeve I4I will be uncovered to such an extent that a flow of two gallons per minute of cooling liquid will pass through the valve. When the handle is swung to such an extent that the pointer I431 is on the portion of the dial marked open the sleeve will be raised to the extreme position shown in Fig. 18 so that a free flow of steam is permitted. This will be the position of the'valve used for heating purposes.

We claim:

In an air-conditioner unit, a casing having an air inlet opening in the lower portion thereof and an air outlet in the upper portion, a. heat-exchange unit in the upper portion of the casing, and means for enforcing an upward flow of air through the casing comprising a panel supported substantially horizontally through the central portion of the casing and blower mechanism suspended adjacent the panel and adapted to draw CLAYTON A. DUNHAM. DAVID N. CROSTHWAIT, JR;

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