US2010001A - Air conditioning system employing steam for heating and cooling - Google Patents

Description

c. M. ASHLEY 2,010,01

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING Aug. 6, 1935.

Filed Aug. 12, 1932 3 Sheets-Sheet 1 INVENTOR. Carlyle M Ashley j mw 5w A TTORNEY 5- (1.4M. ASHLEY 2,010,001

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING Filed Aug 12, 1952 a Sheets-Sheet 2 IN V EN TOR. Carlyle M195 leg A TTORNEYS.

6, 1935- I c. M. ASHLEY 2,010,001

AIR CONDITIONING SYSTEM EMPLOYING STEAM FOR HEATING AND COOLING Filed Aug. 12, 1932 I 3 SheetsSheet 3 IN V E IN TOR. .C'a'rlyle M/lsizley BY ATTORNEY plat d Au 6, 1935 2 010 001 UNITED STATES PATENT oFricE;

AIR CONDITIONING SYSTEM ELIPLOYING STEAM FOR HEATING AND COOLING.

Carlyle M. Ashley, South Orange, N. .L, assignon by mesne assignments, to Carrier Engineering Corporation, Newark, N. J., a corporation of New York Application August 12, 1932, Serial No. 628,558 14 Claims. (cram-9) This invention relates generally to air condiadapted to harbor a cooling medium under sumtioning systems and more particularly to im- 'mer conditions and a heating medium under provements in' methods of and apparatus for prowinter conditions, whereby air circulated in conducing both refrigeration and heating effect utitact therewith will, under one set of conditions,

lized in systems for dehumidifying, humidifying, be heated, and under another set of conditions cooling; heating, as well as controlling the tembe cooled and dehumidified. perature and relative humidity, of air. Another feature of the invention provides a The general. object of the invention is to prototally enclosed water circulation system, for carvide an airheating and cooling system using a -rying out refrigerati and h at processes,

10 common source of steam either for producing adapted to serve the needs'of a boiler and asso- 10 cooling effect or for producing heating efiect. ciatedrefrigeration and air conditioning appa- Thus, under one set of conditions, steam will ratus, losses in water supply being practically be used for producing, refrigeration, whereas, gib e and result n n yi o Purging n under another set of conditions, steam-will be ations. v

used for heating purposes, thesame combination A the f atu p s forlltihzingrextleme- 15 ofapparatus being adapted to serve both pur- 1y small quantities of water for condensing steam I poses.- employed for producing refrigeration, the volume Another object of .the invention is to provide a of water required being substantially only that unitary arrangement of apparatus adapted to cool 4 quantity which the heat of condensation is caso and dehumidify air volumes or to heat air vol- F l fap a Which Will retflinnseries umes by employing steam from a common source, of condenser tubes wetted and clean, common apparatus being employed both for the A further object provides forsupplying water dehumidifying'and heatingpurposes. for condensing purposes only when a controlled Another object of the invention is to provide a supply of steam is being utilized to produce resystem of apparatus in combination with a sourcev frigerating fie w n e Pressure Wit 8 '25 of steam supply under a unitary control, whereby refrigeration system rises above a predetermined the steam may be used under one set of condilimit. tions for supplying refrigeration and under an- A further feature of theinventio'n provides for other set of conditions for supplying heating efutilizing totally enclosed water circuits in com- 33 feet. The control, in practice, enables the arbination with an air heating and cooling system,

grangement of apparatus to operate as a heating whereby desiredwater levels will be maintained and-ventilatingsystem, when increased temperain a steam boiler and evaporator forming part tures are desired; and may readily convert the of the system. 1 apparatus into a system'for cooling and dehu- A further feature provides for automatically midifying air volumes, when decreased temperatransferring liquid from a sourceof supply at one 35 tures and dehumidified atmospheric conditions pressure to a receiving means at a lower presare quired. 4 j v sure, without the intervention of mechanical A u r Object 01" the invention 15 to Provide throttling or feed control mechanism. As arecombined refri rating and heating appara suit, liquid from a'condenser is fed to an evapo- 49 w ich y e operated h absolute e y i rater without the intervention or such a device '40 e that no dangerous refrigerants are employed, as the usual expansion valve which 18 quiet In operation, slmple 'P Afurther feature provides for controlling a'sup 4 and capable either of heating or cooling air volply of steam for producing refrigerating exec;

umes under manual or. automatic control, and 43 whose operating cost makes for efliciency with to ng in pressure of Sam stem.

, great economy. v I A feature of the invention resides in the pmfurther fea ure comprises a steam ejector in vision of a cont-m1 arrangement adapted to Oper combination with a boiler, whereby steam will be ate, under winter conditions, with steam pressure Supplied said for Pmducing desired 59 between certain predetermined limits, and adaptfrigemtmg efiect only when the Steam is between ed to operate under summer conditions with the predetermined Pressure i st-eam pressure between predetermined limits 4; Another feature of the invention provides for higher pressure. g supplying steam to a steam ejector of an air con- Another feature of the invention resides in ditioning apparatus and causing an air condithe use of a common conditioning apparatus tioning-mediumtobecooled responsive to changes in heat load affecting the atmosphere of an en- 7 closure served by the apparatus.

Another feature resides in the provision of a combined evaporator and heat exchanger thereby eliminating a pump which would otherwise be employed to circulate the fluid for a flash evaporator through a heat exchanger.

Further features, covering advantages in structure, assembly and economy, as well as flexibility in operation, and assuring efiicientservice with complete safety under all operating conditions, will be more apparent from the following description of an illustrative arrangement of apparatus and controls adapted to carry out the invention, to be read in connection with the accompanying drawings, in'which:

Fig. l is a schematic arrangement, partly in section, of an apparatus adapted to carry out the invention, generally illustrating the interrelation of parts,

Fig. 2 illustrates diagrammatically a control arrangement to be used in combination with the apparatus of Fig. l,

Fig. 3 isan isometric fragmentary view of a .heat exchange device mounted within a duct,

forming part of the invention, with a portion of the header being broken away to show the interior,

Fig. 4 is an isometric view of one of the troughs employed in the *device of Fig. 3,

Fig. 5 illustrates diagrammatically an evaporator header in combination with a liquid feed system for the evaporator, and a humidifying device above the evaporator,

Fig. 6 is a diagrammatic view of a condenser employed as part of the combination of Fig. 1,

Fig. '7 is a diagrammatic representation of a boiler return'trap. Y

Considering the drawings, similar designations referring to similar parts, and first with particular reference to Fig. 1, numeral l illustrates a boiler having a fire box-l2, burner pipes I, and burners l3. While the boiler may be served with any desired fuel, for purposes of illustration, gas burners are illustrated, the burners l3 being provided with controlled amounts of fuel under the regulation of valve M. A flue l carried off the gases of combustion.

From the top of the boiler, pipes l6 and I1 lead to'pressure reducing nozzle l8 suitably positioned in a head casing and adapted to direct fluid therefrom toward an entrance diffuser 2|. A valve I9 is provided in pipe H for controlling the admission of steam'to nozzle l8, as will be hereinafter described. Conduit 22 connects head casing 20 with a header 23 of a heat exchange device, designated generally by the numeral 42, and shown in greater detail in Figs. 3 and 5. Entrance diffuser 2| leads into discharge diffuser 24 which, in turn, connects through conduit25 with an inlet header 26. (Fig. 6) of condenser 21. The condenser 21, as shown in Fig. 6, preferably comprises an'inlet header 26 and a discharge header 28 connected by a plurality of tubes 53. The tubes preferably are provided with extended surface to promote increased heat transfer. From the discharge header 28, a pipe 30 leads back to the boiler. A boiler return trap 3 whose operation will be hereinafter described, is located below the bottom of condenser 21, but above the top of boiler f0, and is connected to the pipe 3|! by pipe 32. 'Located in pipe 30 are check valves 33 and 34 between which pipe 32 joins pipe 30.

The trap 3|, shown diagrammatically in Fig. '7, is of g a gravity feed type containing a float 62 pivoted at 63, adapted to.-aetuate twovalves 61 and68 in response to the movement of the float. The valves are arranged to be either fully open or fully closed and when one is open the other will be closed. A weight 64 pivoted at 65 and attached to the arm of float 62 at point 66, by an appropriate linkage, is suitably arranged to operate valves 61 and 68. When there is no liquid in the casing of trap- 3| and float 62 is at its lowest. position, valve 61 is open and valve 68 closed. As liquid fills the trap, the float rises, thereby moving weight 64 towards its dead center. When the level reaches a predetermined point, the weight passes its dead center and by gravity drops over, thereupon causing valve 61 to close'and valve 68 to open. The movement of the weight after it passes dead center is precipitate so that the opening and closing of valves 61 and 68 will be immediate and akin to snap action. No limitation is made to the particular form of trap and any analogous means may be utilized for similar purposes, the particular means described being deemed illustrative.

Pipe 35 leads from pipe It to valve 68 of the return trap.3|. Pipe 36 leads from valve 61 of the trap to header 26 of condenser 21 (Fig. 6) and provides an equalizing passage therebetween, whose purpose will be hereinafter described.

Heat exchanger 42 combines a plurality of functions in one apparatus and additionally provides a simple and compact apparatus readily adaptable for use under summer and winter con- -ing conditions will be differently carried on.

Thus, under summer conditions, it operates to cool and dehumidify air, whereas, in winter, it serves to heat the air. Furthermore, under summer conditions, it not only provides a cooling means directly for conditioning air passing in contact with component parts thereof, but also serves as an evaporator for supplying a cooling medium to said means. From a practical standpoint, it may be characterized as a condenser for heating air under winter operating conditions andas an evaporator for cooling air under summer operating conditions. 'Its function to avoid duplication of apparatus will be apparent.

Referring more particularly to Figs. 3, 4 and 5, 42 refers to a preferred form of heat exchanger having a. single header 23. Tubes 29, preferably provided with extended surface, are bent in a U shape and have their ends terminating in tube sheet 59 of theheader 23. As shown in Fig. 3, the ends of all U tubes in each row lie in the same horizontal plane. Attached to the ends of the tubes of each row, is a trough 60. The trough front wall of each trough 60 (Fig. 4) hasa cut-out portion 6|. The liquid feed pipe 12 ispositioned in the top of header 23 directly above the uppermost trough 60. Hence, as undersumm'er operating conditions, a liquid fedfrom pipe 12 will fall into the upper trough and enter U tubes 29 associated therewith. The depth of cut-out portion 6| of the trough is determined by the height of liquid which it is desired to maintain in the tubes associated with the trough. Therefore, when the uppermost'tr'ough and its associated tubes are filled to a desired depth, additional liquid will spill over through cut-out portion 6| and flow into the trough below. Similarly, all the lower rows of tubes and their respective troughs will be 'U tube 29.

charged on the outside of tubes 53. A fan 52' filled to the desired level. Excess liquid will spill through the cut-out portion of the lowest trough and collect in the bottom of header 23, and then.

drain or serve a function'hereinafter described. The fluid evaporated in the tubes and trough finds a'passageway through conduit 22 connecting the evaporator and difiuse 2|.

While the single header and U tube construction of the heat exchanger is illustratedherein, the invention is not limited thereto and, if de- -sired, exchangers having oppositely disposed headers may be used to'carry out similar tions.

Contiguous and on the same level with each row of tubes 29 in the heat exchanger, and parallel to each of troughs 60 is a pipe 3'1 (Fig. 5) extending the length of header 23. The ends of pipes 31 are mounted in a header 69 (Fig. 5) which may be connected to steam supply pipe 35 (Fig. 1) by pipe 38, under control of valve 39.

Each of pipes 31 has a series or; holes therein, a hole being provided opposite one end of each Steam issuing from each hole, as

I under winter operating conditions, is arranged tube.

end of the tube into associated-trough 60. Pipe 40, containing check'valve- 4|, joins the bottom to enterthe oppositely disposed open end of the Condensate willdrain out of'the other of header 23 to pipe 32. Under winter operating conditions the condensate entering troughs :60,

will drain through pipe 40 back into the boiler.

Without reference to automatic features .of'

control, which will be hereinafter described, and assuming that steam. is available from .boiler I!) at a desired pressure, thatevaporator tubes 29 \of heat exchanger 42 are suitably filled tothe desired level, thatva'lve 39 (used under winter conditions) is closed, and thatyvalve l9 (used under summer conditions) is open, refrigeration operation, as desired under summer conditons, will be efiected as followsh Steam from boiler I0 will proceed,to nozzle l8 through pipe l6, l1 and valve I9. The steam is expanded in nozzle 45 F. Reducing the pressure atthe discharge end of the nozzle causes a corresponding reduction in pressure within evaporator 42, which is in communication with the outlet of the nozzle through conduit '22 and'casing 20. Consequently, heat from the air to be cooled, whose temperature is greater-than 4:5 F., will be transmitted through the tubes 29 and cause the water therein to boil: Thus, rbyextractfng the heat from the air to supply the latent heat of evaporation to the boiling water, the air will be lowered in temperature. It is self-evident that such evaporation will produce large volumes of vapor. To prevent building up a pressure in the tubes which would impede or stop evaporation, the vapor must be (removed as fast asit is produced. Its removal from tubes 29 and header 23 and through conduit 22 is accomplished by Y the action of the jet of high velocity steam issu-' .ing from nozzle' l8. The vapor is entrained by;

the steam andcompressed within diffusers 2| and 24 with a consequent rise in saturation temperature and pressure. The compressed mixtureis then discharged through pipe25 into inlet header 26 and tubes 53 of condenser .21. For the purpose of removing the heat of-condensation,'the condenser 21 is mounted within a tank 41. Water from a suitable source is fed to a spray header 48 through a pipe 49 and an aspi rator 50 under the control of valve 5|, and'is dis- I8 to a predetermined pressure, for, example, that at which water will boil at is adapted to draw air from an outside source through an opening 54 in the'tank 41, through the water sprays, over the tubes 53 and to discharge the air to the atmosphere tlu'ough the opening 55. The hot mixture of steam and vapor, at 100 F., for example, within tubes 53 its latent heat to the cooler air blowing over he outside of the will be condensed by giving tubes. The tubes are kept wet by the sprays primarily to increase the transfer of heat from hot vapors to the air. By this preferredmethod. only suflicient water need be supplied by header 48 to keep the tubes 53. clean and wet and to take care of water losses through evaporation.

The liquid condensate from tubes 53 will drain ,into header 29 (Fig. 6) and will be returned to the boiler in a mannernow to be described. As

previously described, trap 3| is connected to line 30 between condenser 21 and boiler It). An equalizing passage 36 betweentrap -3| and condenser 21 is controlled by valve 61 in the trap;

I a passage 35 between the trap and boiler is controlled by valve 68 in the trap. If it is assumed that trap 3| is empty, then float 62 willbe in its lowest position. The valve 68 will be in closed position against the steam pressure in pipe 35 and valve 6! will-be retained in open. position f so'that the pressure in trap 3| will be substantially the same as the pressure in condenser 21. Check valve 34 will be closed by the pressure from boiler l0. Check valve 4| is also closed due to the greater pressure in thetrap (which is substantiallythe same as condenser pressure) than exists in the evaporator. Since trap 3| andcondenser 21 are substantially at the same pressure, check valve 33 will be open due to the .head of'liquid in pipe 39; and inasmuch as trap 3| is lower than the condenser, condensate will fio'w by gravity from header 28 of the condenser, through pipe 30, check ,valve 33 and pipe 32 into the trap. As the level of liquidrises in 3|; the float willrise until,.as hereinbefore explained, the weight I 64 trips, thereby closing valve 61 and opening valve 68. Thereupon, steam pressure from pipe 35, will enter the trap through valve 68 and exert a pressure on the liquid therein. Check valve 33 will immediately close and valve 4| remain closedsincethe boilerpressure is much higherthan-either condenser or evaporator pressure. The trap and boiler'will then be under the same pressure and since the trap is'higher than the top of the boiler, the head .of liquid will cause check valve 34 to openandthe liquidwill flow through pipesv 32 and 30 into the boiler by gravity, thereby providing for boiler f eed. As the trap empties the floatwill drop, thus causing weight 64 to fall to the other side,

whereupon valve 68 will closeand valve 61 open 7 so that the cycle may be repeate While this gravity arrangement is illustrated in connection its attendant troubles. The operation will now be described. A well '43 is provided for accumueliminates a mechanical expansion valve' withj- 23 just above the uppermost trough 60. From separator 44 another pipe H rises vertically to a predetermined height, then, as illustrated, drops to a point well below the level' of the evaporator, proceeds horizontally and then rises to connect with the bottom of header 23. At the lowest point in the last piping series, and adjacent the vertical section of pipe H leading to the bottom of header 23, is connected a pipe 13 which, in practice, may parallel pipe 'H from the point of connection to and into header 23.

As illustrated in Fig. 5, pipes II and l3 terminate within header 23 at a height above the bottom thereof, at which it .is desired to maintain the level of liquid in the header. The pipe -1I is exposed to the heating effect of the surrounding air to assure boiling of liquid in the vertical section of the pipe leading into header 23, while pipe 13 is suitably insulated to prevent such boiling action..

The action of returning liquid from the condenser to the evaporator is as follows: Hot condensate collecting in well 43 rises in tube 10, which may be insulated to prevent its cooling. As the condensate rises in pipe 10, it approaches the evaporator pressure and will proceed to a point at which it begins to boil due to the lowered pressure. The vapor is separated from the liquid in the separator 44. The separated liquid drops into the trap formed by the U bend in pipe IT and then proceeds to build up a supply of fluid in piping 12 leading to the, point of entrance at the top of the evaporator. The piping is so arranged that, in practice, the height of the column of liquid in pipe 10, plus the vertical height of the column of liquid in the trap portion of piping I2, is sufiicient to balance the difference between the pressures in the condenser and evaporator; Thus, as more water from well 43 boils and supplies liquid to pipe 12, the balance ,will be disturbedand cause a corresponding amount to enter the evaporator; This will be carried on until the boiling action in the pipe 10 ceases, whereupon, the balance will be restored and no further liquid enter the evaporator.

. The vapor from separator 44. passesinto pipe I I. v If there is s'ufiicient water in the evaporator, the level in the bottom of the header will be above the point at which pipes H and I3 termi nate, Pipes H and 13 will be filled with liquid and trap the vapor from separator 44 in the pipe II. This will build up a pressure atthe separator 44 so that the boiling actionthere will stop. As a result, no more water will flow from the separator intopipe 12,:since the pressureis suflicient to retain the liquid within pipe Ill.

The vertical portions of pipes II and 13 which rise into the evaporator should be kept sufliclently hot so'that the liquid therein will always tend to boil. As a result, when the water in the evaporator boils and the level in the bottom of header 23 decreases, the liquid in pipes II and 13 will also tend to boil away, thereby relieving the pressure in the line H and separator 44. As this pressure is released, boiling will againtake place in pipe 10 and liquid allowed to flow into"line 12 and intothe evaporator until the level is again restored to the point where liquid once again flows into pipes'll and 13 to build in line 1| sufilcient to stop further boiling in pipe 10'. I

This system normally operates under a relatively high vacuum, to wit, about 5" of mercury,

absolute pressure, in the evaporator-and 2" of mercury, absolute, in the condenser. In practice, some leakage of air will normally occur. As a result, if air and othergases, which make their way into the system, are not removed, a pressure will be built up to the point where further operation becomes practically impossible. To remove or purge these gases, applicant provides aspirator 50 inwater line 49. A pipe 56 leads to the aspirator 50 from the upper part of discharge header 2B of the condenser, the place at which gases tend to collect (see Fig. 6). The water flowing through the aspirator entrains and collects these gases and discharges them to the atmosphere with the spray water discharged from header 48.

To keep the system purged of gases during the season when refrigeration is being used intermittently, a thermostatic switch 14 (Fig. 2) and a small-heater 15 are placed in a container 16 (Figs. 1 and 6). connected to the bottom of header 28 by tube 11. A small amount of water drains from the condenser into container 16. The heat from heater '15 keeps this water constantly boiling. The thermostatic switch 14 is set so that it remains open as long as the temperature of the boiling liquid is below a predetermined point, for example, 110 F. If air collects in condenser 21, the pressure on the liquid in container 16 is increased so that the boiling point of the liquid is thereupon increased. When it increases beyond the predetermined point, say 110 F., the switch will close an electrical circuit, which will laterbc described in detail, and cause water valve 5| to open, whereupon the aspirator 50 will function to purge the condenser. 'When a suflicient vacuum is again established, the switch will open and water valve 5| close. If desired, a pressure operated switch may be used instead of one operative responsive to temperature changes. As will be hereinafter pointed out, this circuit provides an auxiliary operating feature, designed primarily to keep the system purged during those periods when refrigeration is requ red at infrequent intervals. y

In that it is desired to operate the purge intermittently and to maintain. the system constantly under a vacuum, as previously explained, it is self-evident that some means must be provided to close the passage 56, whenever the aspirator is not functioning, to prevent air flowing back through spray header 48, aspirator 50; and pipe 56 intothe condenser 21. For this purpose, a valve I E59, similar in construction to valve 5| 'is provided. As contemplated by applicant, valve by placing a check vvalve in pipe 56 and locating the valve 5| between the aspirator 50 and' the spray header 48. However,- with suchan arrangement; it is apparent that if the check valve should for any reason become inoperative, the system would be flooded with water, whereas with applicants preferred arrangement, the only damage which would resultfrom non-operation of valve I would be the filling'of the condenser with air. Although this would cause excessive use of water for purging, no serious damage could be done to erence to controls which will be hereinafter described, valveIil will be retained closed and valve 39 open. Steam from boiler I will flow through pipe 'I6, pipes35 and 38, valve 39 and header 69 (Fig. into pipes 31. The steamwill be discharged from pipes 31 through the holes therein, as hereinbefore-described. These holes are arranged to direct the steam toward one end of each U tube 29. As may benoted by reference to Fig. 5, the holes in tubes 31 are so positionedjhat the steam will'enter tubes 29-over the upper edges of the troughs. The tubes will thereupon be heated and condensate will drain through the opposite ends, fill the troughs and collect in the bottom of header 23. Pipe 4.0 leading from the bottom of header 23 will fill and open check valve 4I, close valve 33, and open valve 34, whereupon the water will drain by gravity back to the boiler. This is due to the fact that the pressures in the boiler and heat exchanger are substantially the same and the head of liquid will be sufficient to cause the flow back to'the boiler at the lower level.

An extension of pipe 35 is shown which may lead to radiators of conventional design located in a garage, servants quarters or other places which cannot be heated practically from a central heat exchanger.

Althoughit is desired, under winter operating conditions, to air bind the condenser, diffusers and the head casing 20 to prevent the heating of these elements, it is also desired to keep the heat exchanger free from air so t at it may function properly. For this purpose, athermostatic air vent I10, generally well known in the heating art, is connected through pipe "I with condensate drain 40, and subjected to the hot steam vapors in 42. As long as the hot steam can afiect the thermostatic element of the vent I10, the vent will remain closed to the-atmosphere. However,

as air collects in the pipe "I and vent I the I thermostatic element cools o'if; opens a valve' and allows the steam to force the air out of the heat exchanger. It is apparent, from a foregoing sec-( tion of this specification, that underv summer con- 1 ditions, the vent I10 would be open to the atmosphere at alLtimes. To prevent air working its way into the system'through the'vent I10 under summer operating conditions), a ,check valve I12 is placed in the line "I. When the vent I 10 is open and the heat exchanger 42 is'u'nder vac!- uum, atmospheric pressure will keep the check valve tightly closed. If any radiators are connected onthe extension of line 35, the possibility of which was previously pointed out, it is neces sary to insert a two-way thermostatic air vent I13 in pipe I1. This. valve is similar'to I10 but is arranged to break anyvacu'um existing in the system under winter operating conditions as well as vent air as desired. Its operation is similar 'to vent I69, hence, no further description is thought necessary. a

Forthe' purpose ofcontrolling the relative humidity.,,of the air'during the heating season, a pan I60 (Figs. 1 and 5), containing a variable amount of water, as will be hereinafter described,

is placed in the duct 51, preferably above the heat exchanger device 42, and is supplied with heat from any desired source, as, forexample, the steampipes I65. A hygrostatic switch I64, located in the space to be conditioned and responding to changes in relative humidity of the air. therein, is-adapted to close an electrical circuit and vaporize the water, and similarly, there will be an appreciable interval before the hygrostat I64 will'respond to the increased humidity. A

valve. small enough to supply .water at just the rate at which it could be evaporated by the heat and absorbed by the air would not be very practical. To prevent flooding, and more important, to prevent over humidification, a,float'. l63 re- I66, is placed in the electrical circuit, (to bejdescribed in detail later) inseries with the hygrostat I64. The floatI63 will operate switch I66 to sponding to changes in the level of water in pan 7' .I60, and adapted to operate an (electrical switch break the electrical circuit, Hence, closing the valve I62 (as by a spring) as the'level in pan I60 rises to a certain inaximum. As the water evaporates, the level in I 60 will decrease and the float will fall. At a certain minimum, the float will close switch, I66, and if hygrostat I64 is still closed, the circuit will again be closed to open the water valve I62 to supply water to pan I60.

Obviously, the float I63 in its preferred form,

will be set to operate between close limits, hence, supplying only a small quantity of water to the pan I60 before it operates to close valve I62. The float I63 inmany cases will operate to open and close water valve I62 several times before the hygrostat I64 operates, indicating, of course, that further humidification is unnecessary. 'In this manner, a very fine and smooth control of humidity is assured.

. The heat exchanger 42 is mounted within a duct 51 (Figs. 1 and 3) so that. air from fan 58 serving the system will be forced over the tubes 20 and be heated or cooled, depending upon whether the heating or refrigeration process. is

" being carried on; After being heated or cooled by contact with tubes 29, the air then proceeds- .through 'duct 51 to the space to be conditioned.

When air is being cooled by exchanger 42, as

under summer requirements, moisture will be condensed from the air.

To prevent, rusting and other deteriorative eflects, eliminators I14 are provided in duct 51 below the heat exchanger. The eliminators I14 (Fig. 1) comprise a series ofarcuate metal plates extending across the duct 51.- The lower edge ofeach plate is turned upwards, thereby forming a gutter. The plates are preferably mounted on an angle with the horizontal, so that moisture deposited on the ,tubes 29 may fall, collect in. the gutters of the eliminator plates and drain to any desired common source. 1 Applicant's system has been-designed to operate between certain pressure limits un'der winter operating conditions, as, for example, between 0 and 4 pounds per square inch, and to operate under contacts II9 the operation secondary winding summer operating conditions, when steam is employed for refrigeration purposes, at pressures between different limits, as for example, between 10 and 14 pounds per square inch. This differential in pressure limits has been utilized by applicant in the design of a control arrangement adapted to complete the system and make it entirely safe in operation as well as automatic in its function.

Referring to Figs. 1 and 2, numeral I8 represents a duplex switch mounted on boiler I0 by pipes and 8|. The switch is of the type in which an electrical connection is made when the pressure in boiler I0 drops to' a certain low pressure, for example, ten pounds per square inch gauge pressure, and is broken when the pressure rises to an upper limit, for example fourteen pounds per square inch. It is evident that the switch could be set to operate within any desired pressure range, The device, therefore, operates responsive to changing boiler pressures. It also operates responsive to changes in water level within the boiler, thus carrying out a second function. A float, not shown, in the body of device I8 is adapted to open the electrical connection shown in Fig. 2 when the level of water in boiler I0 drops below a predetermined point. This connection remains open until the boiler is again filled to a safe level, as through inlet I58 leading from a desired source of supply. Sight glass I9 is mounted on the device to give a visual indication of the liquid level in boiler I0. Another pressure switch 82 is mounted on and connected to the boiler by a pipe 83. This switch 82 is adapted to operate three electrical contacts I43, I I9 and I20. Contacts I I9 and I 20 close andcontacts I43 open when a pressure, for example, of 4 pounds per square inch is attained in the boiler. When the pressure drops to 0 pounds per square inch, contacts I I9 and I20 open and contacts I43 close. Contacts I43 control the supply of fuel to the burners during winter operation, contacts I20 the operation of the air circulation fan motor and of the condenser fan motor. A third pressure switch 84 is mounted on and connected to boiler I0 by pipe 85 and operates responsive to boiler pressure to control an electrical contact arm I26. When the boiler pressure rises, for example, to 13 pounds per square inch, arm I26 will make a connection with contact 121 to open steam valve I9, admitting steam from boiler to nozzle I8. The arm will remain in contact until the pressure drops, for example, to 9 pounds per square inch when it willbreak contact I21 and make another connection at contact I32 to close valve I9.

Referring to Fig. 2, transformer 86 has its primary winding 8! across a source of 110 V. current. This line includes a two-pole hand. switch 88 and thermal switches 89 and 90. The closing of switch 88 energizes primary winding 81, making current available to the secondary circuit, whose operation will hereinafter be described.

A five-pole double throw switch, generally designated. 9|, enables positive control of the sys-. tem by an unskilled operative,'under, winter and summer conditions.

'When the center and bottom row of contacts are connected, the system will function under winter controLwhereas if the center and top row of contacts are connected, the system will be under summer control. v

By reference to Fig. 2, it will be noted that I00 of transformer 881s arranged to give two low voltages, in practice, prefadjacent valve I 4,

transformer 86. The. winter/summer switch 9| isclosedon the summer side, with the center terminals connected to the upper terminals. The closing of switch 9| completes a circuit across the 110 V. line including leads 92, thermal switch I38, leads 93, contacts 94 and 95 of switch 9|. lead 98, heating element I5 and lead 91 back to switch 88. Element I5 thereupon heats up and starts the water boiling in its container I6, connected to discharge header 28 of the condenser as previouslyv described. If the system has been inoperative for some time, the condenser will be filled with extraneous gases andthe boiling temperature of the water in container I6 will be high enough to actuate contact arm 98 of thermostat I4 to make contact at 99, thereupon completing the following circuit: Secondary winding I00, lead I0 I, contact arm 98, contacts 99, lead I02, contact I03 and I04 of switch 9 I, condenser water valve 5| and valve I59 in parallel therewith, and lead I05 back to secondary winding I00. The completion of this circuit will cause valve BI and valve I89 to open simultaneously, whereupon, aspirator 5.0 will start purging the condenser. When the action of the aspirator has .produced a s'ufllcient vaccum in the system so that the temperature of the boiling liquid in container "I8 drops to a predetermined point, arm 98 will thereby shutting ofi water valve 5|, and simultaneously closing valve I89. The arm 98 is so arranged that it makes contact either. at 99 or at I05, and it always is in one of these two positions. Assuming that thermostaticswitch I01,- located in the space to be conditioned, is closed, thus indicating that the space requires refrigeration, and assuming that the burner pilot, 'not opens valve I4 to admit fuel to burners I8 which I will be ignited bythe pilot; thereupon supplying heat to boiler I0. when valve I4. opens, to allow fuel to proceed to the burners, amechanical connection'closeslimit switch II4, shown on Fig. 2

whereupon the. following circult is closed: Secondary switch II4, leads H5 and I02, contacts I03 and I04 of switch 9|, condenser water valve 5|, valve I89, and lead. I09 back to secondary winding I00. This causes valves 5| and I09 to open, thereby allowing water to flow through aspirator50 and spray header 48-onto the condenser tubes. After- .the burners have been in operation awhile and 'the pressure in boiler I0 reaches 4 pounds per lead I09, contacts IIO of 10 pounds per square break its contact at 99, 1

winding I90, lead IOI,

' square inch, pressure switch 82 operates to close connections H9 and I20, completing acircuit including the 110 volt line, lead 92, then in parallel through leads 93 and H6 and their respective contacts 94, 95 and I11, II8, respective switches H9 and I20, motor|2| of fan 52 andmotor I22 of fan 58 respectively, leads I23 and I24 respectively and back to starting point through lead I25. This will cause air conditioning fan 58 and condenser fan 52 to operate.

When the pressure in the boiler reaches 13 pounds per square inch, contact arm I26 of pressure switch 04 moves to make contact at I21, closing the following circuit: 20 V. terminal of secondary winding I00, leads II3, I28 and I29, contact arm I26,-contact I21, winding I30 of valve I9, and lead I3I back to secondary winding I00. The energization of winding I30 opens steam valve I9 and allows steam to enter nozzle I8, thereupon starting up the cooling or refrigeration action in the heat exchanger 42 which then functions as an evaporator, as previously described. If the pressure in boiler I rises to 14 pounds per square inch pressure switch 19 will open, thereupon breaking the circuitfor operat-- ing fuel valve I4, which will then close,'as by a spring. The closingof valve I4 causes switch I I4 to open, as by a mechanical linkage arrangement, whereupon the c'rcuit including water valve and valve I69 will e broken and the valve caused to close. However, steam valve I9 will still remain open and continue to supply steam to nozzle I8. The consumption of steam, however, is normally relatively large with respect to the reserve capacity of the boiler. Hence, if room thermostat I01 is still demanding further; cooling, boiler pressure will soon drop to pounds per square required, the fuel valve will remain closed andthe pressure in boiler I0 continue to drop. When the pressure drops to 9 pounds per square inch, arm I20 of pressure switch 84 moves to make contact at I32 closing a circuit including 20 V. terminal of secondary winding I00, leads II3, I29,

I29, arm I26, contact I32, winding I33 of valve I9 and lead I3I back to the transformer. The energization of winding I33 causes valve I9 to close, therefore cutting off the steam to nozzle I8.

With steam valve I9 and fuel valve I4 closed, the

pressure in boiler I0 will drop slowly until at 0 pounds per square inch, contacts 9 and I20 of pressure switch 82 will be broken thereby stopping motors |2I and I 22 operating respectively condenser fan 52 and air conditioning'fan 58. If it is desirable to keep the air conditioning fan 58 operating constantly, to insureeirculation of airin the conditioned space, contacts I20 may be short circuited through leads I34 and I35 by clos-' of switch 9| from the upper to the lower set of contacts. If the system has been inoperative during the intermediate season when neither valve 39 will thereupon close.

heating nor cooling is required,- air will have leaked into the system. This fact is taker-radvantage of,as previously pointed out, under winter conditions to air bind condenser 21 and diffusers 2| and 24 to prevent their heating. The

shift of switch 9| to the lower contacts retains valves 5| and I69 closed so that the system can n-otxbe purged by the aspirator, nor can the air .escapefrom the'condenser because of valve I69.

The closing of switch 9| will cause a circuit to be completed including secondary winding I00,

lead IOI, arm 98 of thermostat 14,- contact .99.,

son, thermostat I01 is short circuite'd through leads MI, 109, and contacts I42, IIB of winter/summer switch'9l. The completion of this circuit will open fuel valve I4 to cause the production of steam in boiler I0. When the boiler pressure rises to 4 pounds per square inch, switch I43 will open, thereby closing the fuel valve, and 'when the boiler pressure is reduced to zero, the

fuel valve will again open, thus; steam for heating is constantly available.

A thermostat, generally designated I44, located in the space to be heated, controls the operation of motor -I22 for air conditioning fan 58 and steam valve 39. Assuming the space requires heating, then movable arm I45 of thermostat I44 will make contact at I46, thereby completing a circuiirincluding leads IN and 141, contacts I48 and I49 of switch 9|, lead I50, arm |45,'eontact I46, winding I52, and leads I28 and H3 to the 20 V. contact of secondary winding I00. Steam valve .39, operative responsive tothe completion of this circuit, will thereupon .open and admit steam to the exchange device 42, which now serves as a heat radiator. If the space becomes too, warm, the arm-I will make contact at I53,

thereby closing a circuit including leads IM and I41, contacts I48 and I49, lead I59; arm I45, contact I53, winding I54, leads I28 and H3 to the 20 V. contact of'secondary winding I00. Steam While two circuits are provided for positively opening and closing valves suchas I9 and 39, it is obvious that a spring type valve may be employed whereby a circuit will be completed for operating the valve in one direction, the valve being operated in the other direction by spring action upon the break ing of the circuit.

When valve 39 is opened, as previously described, its operation by any suitable means causes arm I55 to close a circuit, including the I56, arm I55, lead I5I, motor I22 of the air conditioning fan 58 and leads I24 and I25 back to the 110 V. line, leads 92 and H6, contacts H1 and humidifier to absorb water vapor. 'As previously shown, the fan 58, under winter operating conditions, can only be running when the steam valve is open. Further, when the steam valve is open, the contact I43 of pressure switch 82 will nor- -mally be closed, and the fuel valve open. The

humidifier circuit is placed in series with the contact I43 of pressure switch 82, so that it will be inoperative unless this contact is closed. If it is assumed that contact I43 is closed and that there is no water in tank I60, then contact I66 will be closed, and, assuming further that the hygrostatic switch I64 is closed, indicating that humidification is required, a circuit will be completed including the V. terminal of secondary winding I00, lead II3, pressure switch I8 (closed below 10 pounds per square inch steam pressure), contact I43, lead I09, contacts I10 and I42 of switch 9|, lead I4I, pilot switch I08, lead I6'I,

hygrostatic switch I64, contacts I66, operating responsive to float I63, water valve I62, leads I68 and IOI back to the secondary winding I00.

Energizing this circuit causes the-water valve I62 to open and supply water to the humidifier pan I60. As was explained before, the float I63,-responding to the water level in humidifier pan I60, will open contacts I66, when the water level reaches a predetermined maximum, thereby breaking the circuit. Valve I62, willbe arranged 'to close under the action of a spring or weight.

As the level decreases, the float will close contacts I66 at a predetermined minimum, thereby again closing the circuit and opening valve I62. It will be understood that this cycle maybe repeated several times before the hygrostatic switch I64 operates to break the circuit. It is apparent that if the pressure switch 82 operates condenser to the evaporator, and. various other.

matter herein disclosed but not claimed.

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention may-be made without departing from its scope, it is intended that all matter contained in theabove description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United- States, is:

1. An air conditioning apparatus of the character described, comprising a source of steam, a. first path for steam from said source, and. means including a steam ejector in communication with a heat exchange device wherebysteam supplied ratus serving said unit for increasing the temperature thereof under winter operating conditions.

3. An air heating and cooling system, comprising means for supplying steam to an ejector, a heat transfer unit in communication with the ejector, the dischargeof steam within the ejector.

being adapted to evaporate liquid within the unit to cause a reduction in temperature within the unit and means for supplying steam directly t the unit,to cause a heating thereof.

4. In a system for heating and cooling enclosures, a source of steam, steam ejector apparatus in communication with a heat transfer unit, means for discharging air over said unit, means operative-responsive to steam pressure between certain predetermined limits for admitting steam to the ejector apparatus whereby the unit will be cooled by the evaporation of liquid therein, and means operative responsive to changes intemperature within the enclosure for admitting steam to the unit to cause a heating thereof.

5. In an air conditioning system, a heat.transfer device, a fan for discharging air over said device, a steam ejector in communication with said device, means for supplying steam to said ejector whereby liquid within said device will be evaporated and said device will be cooled, and other means for admitting steam directly to said device whereby it will be heated.

6. In an air conditioning system, a heat transfer device, a steam ejector in open communication with said device, a source of steam, means for admitting steam from said source to said ejector whereby a liquid within said device will be evaporated to cool the device, means for admitting steam directly to said device whereby the device will be heated, and a fan for discharging cation with said unit, means for supplying steam to said ejector whereby the liquid in the unit will be evaporated and the unit cooled, other means for supplying steam into the unit whereby the unit will be heated, and a fan for discharging air over said unit.

9. An air heating and cooling system comprising a source of steam, a heat transfer unit, a steam ejector in communication with the unit, means operative responsive to steam pressure within certain limits for admitting steam to said ejector' whereby liquid in the unit in communication therewith will be evaporated and the unit cooled, and other means for admitting steam to said unit for causing a heating thereof.

10.'In a system for heating and cooling an enclosure, a source of steam, a heat transfer unit, a steam ejector in communication witlr'said unit, means for admitting steam at certain pressures to said ejector, means for admitting steam at other pressures directly to said unit, the admission of steam to said ejector being adapted to cause evaporation of liquidwithin said unit to cool said unit, the admission of steam'directly to said unit being adapted to cause a heating of the unit, and a ianfor discharging air over the sur-' faces of said unit.

11. In a heating and cooling system, a heat transfer device, including a plurality of tubes, means for retaining .a desired quantity of liquid in the bottom of said tubes, a pump in communication with said device, said pump being adapted to cause evaporation of said liquid within said tubes, thereby to cool said device, means for admitting vapor directly to said device to cause a heating thereof, and means for-discharging air over the surfaces of said device.

12. In an air heating and cooling system, a heat transfer device, including a receptacle for fluid means for retaining a volume of liquid in said receptacle, a means in communication with said device for reducing the pressure therein under certain conditions, means for discharging a vapor within said device under other conditions, and means for passing air over the surfaces of said device.

13. In a heating, and cooling system, a heat transfer device, including a plurality of tubes, means for retaining a desired quantity of water in the bottom of the tubes of said device, a steam ejector in communication with said device, a source of steam, means for admitting steam from said source to said ejector whereby a portion of the water in said device will be evaporated and the device cooled, 'other means for admitting steam from said source directly to said device, whereby the device will be heated, and means for discharging air over the surfaces of said device. 14. An air conditioning apparatus of the character described, comprising a source of steam,- a first path for steam from said source, and means including a steam ejector in communication with a heat exchange device whereby steam supplied ing steam from said source, thereby to produce 20 the device.

heating efiect within CARLYLE M. ASHLEY.

CERTIFICATE or conmzcr org.

Patent No. 2,019,001 August 6. 1935.

CARLYLE M'. ASHLEY.

' It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, first column, line 7, for' "diffuse" read diffuser; page 5, first column, line 58. after "170" insert the parenthesis' mark page 9, li'rst column, line 15, claim 12, for "fluid" read liquid; and line 16, s'trilteout the article "a"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of November, A. D. 1935.

Leslie Frazer (Seal) .Acting Commissioner of Patents.

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