US2081905A - Air conditioning system for vehicles employing steam ejectors - Google Patents

Description

June 1, 1937. c. M. ASHLEY 2,081,905 I 'AIR CONDITIONING SYSTEM FOR VEHICLES EMPLOYING STEAM EJECTORS Filed Aug. 12, 1932 2' Sheets-Sheet 1 a- @{0 00 iogooooo :00000- 1910000 Q IN VEN TOR. CARL YLE M ASHLEY Patented June 1, 1937 REISSUED m ,a so

AIR CONDITIONING SYSTEM FOR VEHICLES EMPLOYING STEAM EJECTORS Carlyle M. Ashley, South by mesne assignments,

Orange, N. J., assignor, to Carrier Corporation,

Newark, N. J., a corporation of Delaware Application August 12,

18 Claims.

This invention relates to air conditioning systems for passenger cars, and more particularly, to methods of. and means for controlling the temperature and relative humidity of a car enclosure by a combination of apparatus using steam for producing desired refrigeration effect.

The general object of the invention is to condition the atmosphere of a series of cars of a train by utilizing a steam supply from a central 1; source. The steam supply may be primarily employed for purposes other than the production of desired refrigeration effect for air conditioning purposes, and ordinarily its chief purpose will be for driving locomotive and steam auxiliaries.

13 The pressure of the steam supply will, therefore, vary, depending upon the character of the boiler. as well as the demands of the locomotive to be driven, without regard to the relatively lower pressures required for producing refrigeration effeet in car conditioning systems remote from the locomotive.

A further object is to arrange for distributing steam from a, central source to a plurality of points remote from said source, the pressure of the steam at each' of said points differing from each other and from the pressure at the source.

The refrigeration efiect resulting from the use of steam at each of said points will, however, be substantially the same at each of the cars, or

may vary, as desired, so that for different purposes, some cars of the same train may be afforded greater refrigeration effect than will be afforded to other cars in the train. 4

A further object of the invention is to afford a system of regulation in combination with an air conditioning apparatus for a passenger car adapted to control the temperature and relative humidity of air within the car responsive to changes in heat load affecting the atmosphere of the car. The control of outdoor air volumes and return air volumes, as well as the continued circulation of desired quantities of air at predetermined temperatures and dewpoints is afforded under manual and automatic control, so that, in fact, weather may be manufactured at will to suit varying needs or tastes; and may also be so regulated that equable and constant conditions may be produced and maintained throughout the car area, regardless of variation in climatic conditions outside the car.

Another object is to provide refrigeration equipment which does not require the use of a refrigerant other than water. The employment of water in liquid and vaporous form is caused to produce desired refrigeration and dehumidifica- 1932, Serial No. 629,177

tion efiect in the conditioning of car interiors. Due to the safety of water over refrigerants, such as ammonia, for example, no hazards are invited, nor are passengers exposed to injury from the effects of a dangerous refrigerant as might readily occur in the event of leakage or train wreck. It is obvious that water is always universally available and is generally inexpensive, so that the system may be readily replenished, with very little trouble.

A feature of the invention resides in the provision of an evaporator for cooling a supply of liquid for conditioning a railroad car, and supplying steam to an ejector serving the evaporator at desired pressure, regardless of the pressure of the steam supplied to the car wherein the evaporator is located. 7

Another feature provides for the operation of an evaporator when steam is .supplied to an ejector in combination therewith at a desired pressure, and for cutting off the steam to the ejector when the pressure thereof falls below a predetermined limit.

Another feature provides for supplying steam to an ejector nozzle for causing evaporation to take place in an evaporator, said steam being adapted to entrain vapor from the evaporator and discharge within a condenser. This feature embraces the use of a common passage connectingthe evaporator and condenser, within which the steam is discharged.

A further feature resides in the provision of a combination cooling tower and condenser, having means for spraying water over the condenser to maintain its surface in a wetted condition, and means for intaking a volume of air at one side of the car and discharging it at the other side or through the top in such manner as to dissipate the heat resulting from condensation of vapors within the condenser.

Another feature provides means for collecting air and excess condensate within the condenser and means for supplying liquid' to the surface of the condenser in such a manner as to cause the liquid to entrain and discharge the air and excess condensate substantially at atmospheric pressure.

Another feature provides a plurality of closed water circuits, water from one of said circuits being subject to evaporation, said evaporated water being delivered to another of the circuits after passing through the condenser.

Another feature resides in the provision of an evaporator in one water circuit, the provision of a condenser in another water circuit, and shifting liquid from one circuit to the other circuit while maintaining desired water level in the evaporator.

Another feature provides a series of closed fluid circuits in an air conditioning system, one of said circuits including an evaporator, another of the circuits including a condenser, and a third 01 the circuits including both the evaporator and condenser.

Another feature governs the operation of a pumping device for supplying water to a condenser, the pumping device being operative only whensteam is supplied to an ejector for causing evaporation in an associated evaporator.

Still another feature governs the supply of steam to an ejector only when atmospheric conditions within a car are beyond predetermined temperature limits. v

Another feature provides the combination of a pump for supplying water to a condenser anda fan for causing circulation of air to cool said water, the pump and fan being arranged to 0perate only when atmospheric conditions in an enclosure to be conditioned require amelioration.

Another feature of the invention resides in the provision of means for accumulating condensate and gases, whereupon the gases will be purged from the system and part of the condensate delivered to the evaporator, the remainder of the condensate being used to augment a supply of condenser water.

Another feature covers the use of a reservoir and means in combination therewith for withdrawing liquid from the reservoir for condensing purposes and alsofor purging a condenser.

Another feature makes provision for an evaporaton'a conditioning device and means for feeding a conditioning medium from the evaporator to the conditioning device only when the temperature of said medium is below a predetermined limit.

Another feature provides for controlling the circulation of fluid between an evaporator and an air conditioning unit, the'control being dependent upon the temperature in the evaporator and the temperature within the enclosure to be conditioned.

Another feature provides for governing the temperature of an enclosure between predetermined temperature limits, yet assuring desired circulation of air regardless of degree of fluctuation of temperature in the enclosure.

Another feature covers the use of an ejector, means for supplying steam to said ejector whereby liquid in an evaporator may be cooled, and a condenser in combination with the evaporator, the flow of steam to the ejector, and hence, the operation of the evaporator being dependent upon the maintenance of desired pressures within the condenser. Further, the flow of steam to the ejector may also be under the control of means responsive to changes in temperature of condenser.

Further objects and features providing advantages in construction and assembly of applicant's system, as well as making for efllciency and.

economy in the operation thereof, will be more apparent from the following detailed description of one form of the invention, applied to a railroad car, to be read in connection with the accompanying illustrative drawings, in which:

Fig. 1 is ,a schematic drawing, partly in section, of a system incorporating the invention;

Fig. 2 is a diagrammatic control arrangement.

adapted to be applied to the assembly of apparatus illustrated in Fig. 1;

Fig. 3 is a representation of a series of passenger cars, each equipped with a steam ejector system of car conditioning, served by a common source of steam.

Considering the drawings, similar designations referring to similar parts, numeral 5 represents. generally, an air conditioning unit forming part of a complete system of air conditioning. As illustrated, it is adapted to be mounted within the upper area of a railroad car adjacent to and between the upper deck and the half deck. The unit equipment includes a fan 6 which draws outside air through an intake opening 1, the free area of which may be variably controlled by dampers 8. outside air, the fan may also draw return air from the interior of the car through openings 9 under the control of dampers Ill. The outside air or mixture of outside and return air passes through a series of heating coils II, which are normally operated under winter conditions, and through a series of cooling coils I2 which are normally operated under summer conditions, be-

fore entering fan 6 for distribution within the car interior. Under summer conditions, with which this invention is primarily concerned, the air passing through cooling coils I 2 will have its temperature lowered to a predetermined dewpoint and, in general, will leave the cooling coils For purposes of in cold, saturated condition. raising the dry bulb temperature and lowering the relative humidity of this cold, conditioned air, a volume of bypassed air from the interior of the car may be admitted through openings 18 under control of dampers l9. This bypassed air, in practice, will mix with and augment the volume of conditioned air, so that a final mixture, adequate for circulation requirements, and at a comfortable temperature and relative humidity, will be discharged by fan 6 to a series of ducts and outlets serving the enclosure tov be conditioned. Dampers l0 and I9 are preferably interconnected by link mechanism 68 under control of damper motor 20. This damper motor will operate the link mechanism responsive to a control instrument such as a thermostat 69, pcsitioned within the conditioned area. Thus, when the temperature in the conditioned area rose above a predetermined limit, the thermostat would cause the damper motor to operate, whereupon more air would be admitted through dampers i0 and less through dampers I9. As a result, a greater volume of air would be dehumidifled and less bypassed air utilized for reheating purposes. On the other hand, if the temperature in the enclosure required more heat in order to maintain desired conditions, dampers l0 would tend to close and dampers l9 tend to open, whereupon, less air would be conditioned and more bypassed, to supply greater reheating efiect. Dampers I 0 and I9, as illustrated, are differentially connected, so that when one series tends to close, the other tends to open.

Under winter operating conditions, or whenever it is desired to use heating coils -ll, steam -may be admitted through pipe l3 under control of valve H which may be suitably regulated by a thermostatic device not shown, in the usual manner. Drain pipe I! removes condensate from the heater for disposition as may be desired. As under summer operating conditions. outside air, or a combination of outside and return air, will pass through the heater coils and In addition to drawing raise to a desired high temperature. Bypassed air may then be employed to augment the volume of intensely heated air and modify its condition prior to discharge by the fan within the car interior.

Cooling coils |2 are supplied with a cooling fluid, ordinarily cold water, by pump l6v from a source of supply within evaporator 15 forming part of a system of refrigeration hereinafter more fully described. Supply line 2| feeds the cold water to the coils which is returned to the evaporator through line 22, and discharged therewithin preferably in the form of spray, after haitl'isng removed heat from air passing over the co In carrying on a refrigerating process, it is generally considered essential to-employ (l) a medium which will be vaporized by the absorption of heat, then compressed, and finally condensed, thereby giving up the absorbed heat; (2) a source of power for the purpose of compressing the vapor and (3) a second medium for removing and dissipating the heat absorbed by the first medium. In contrast to the accepted form of devices for carrying out such a refrigeration cycle, the present invention provides an arrangement which uses the same agency for all three purposes, namely, water in liquid and vaporous form.

Evaporator l5 has an outlet, as illustrated, in communication with converging nozzle 23, joining diverging nozzle 24, connecting by suitable fittings to condensing device 25. The elements 23 and 24 may be generally designated as a diffuser. In the head of converging nozzle 23 is suitably positioned a nozzle 26. The combination of the diffuser and nozzle 26 is generally termed an ejector. In operation,-a fluid, such as steam, will be supplied to the nozzle 26 and expanded therein to a predetermined pressure which, for example, in practice, may correspond to the boiling point of water at 45 F. Lowering the pressure at the discharge of nozzle 26 will cause the pressure within evaporator l5 to be lowered, and consequently, the water will boil or evaporate. This action will result in absorption of the latent heat of evaporation necessary to'carry on such boiling action, from the remaining water in the evaporator, thereby cooling it. To aid the evaporation action, liquid is returned to the evaporator, as already noted, and, as illustrated, in the form of spray, thereby providing a maximum area of liquid surface and evaporation. The liquid is discharged within the evaporator, preferably through spray header 40, and suitable nozzles may be provided for creating desired vaporizer or atomizer action, so that maximum evaporation, and hence, maximum cooling effect, may be accomplished, since the temperature of all spray droplets in their course to thereservoir 54 at the bottom of the evaporator, is substantially the same. The water vapor resulting be removed from the evaporator l5 due to the operation of high velocity ejector 26. In effect, the steam expanded in the nozzle will produce an area surrounding the nozzle at lower pressure than that in the evaporator, resulting in a flow of vapor from the evaporator which is entrained by the steam and passes into diverging throat 24. As illustrated, throat or nozzle 24 increases in area as it approaches condenser 25, hence, the pressure of the steam and vapor passthrough will be increased with a corresponding increase in saturation temperature. The

' Such condensing water 46 leads to the tank 3|.

from the boiling action will compressed mixture then passes into condenser 25. This may be cooledin any desired manner, and, in the system illustrated, a special arrangement is employed combining a cooling tower with the condenser, for the purpose of liquefying the mixture of steam and vapor fed to the condenser from the diffuser. The condenser 25 comprises inlet header 21 and outlet header 26, connected by a series of tubes -29. The tubes are preferably provided with finned or other extended surface to promote increased heat transfer.

To remove the heat of condensation, pump 30' withdraws water from storage tank 3| which is then fed through pipes 32 and 33 to spray headers 34 and 35 and then discharged over the surface of the condenser. Aspirators 36 and 31, provided respectively in pipe lines 32 and 33, will be hereinafter described. Fan 38 draws air from outside the car through opening 39 and discharges it through opening 4|. The air will absorb some of the spray water, causing a reduction in temperature of the air and water. The contacting of the water and air with tubes 29 causes the desired condensing action. Opening 4| is provided with a series of dampers arranged to permit the discharge of air therethrough whenever the fan is in operation; but when the fan is inoperative, and noair pressure is exerted against the dampers, they will fall back into closed position and prevent rain,-

cinders or other foreign matter from entering. as is not evaporated and falls into the condenser well or pan 42 will drain through outlet 43 into a storage tank 3|. Partition 44 defines the extremity of the condenser well and prevents water entering the fan compartment.

In connection with replenishing the water supply of storage tank 3|, it should be remembered that this system was primarily designed to be incorporated in a railroad car. tirely possible to place a tank on the .car large enough to carry suflicient water for make-up purposes. However economy of weight and space are of prime importance. Applicant provides a novel system whereby all the water needed for continuous operation of the system is obtained from the steam supplied to the system. Not only does the steam supply requisite energy for compression, but it further supplies the refrigerant and the necessary condenser water. 1

From the bottom of the separator 45, a pipe Hence, any water which is separated from the steam in the trap will be forced through pipe 46 (by steam pressure) into tank 3|. To prevent live steam from blowing into tank 3|, a thermostatic trap 15 is placed, in the line 46. The trap 15 is of the type in which a thermostatic element controls the open ing and closing of a valve. The thermostat -is so arranged that as long as there is condensate in 45, the valve will remain open, but as soon as steam strikes the thermostat, the valve will' "26 is removed from the system and discharged into the condenser water system in a manner to be hereinafter described.

It would be en- During the summer season, it is apparent that 5 care of from the above sources is made-up from an auxiliary condenser. The condenser comprises a piece of tubing 13, preferably finned to increase its heat radiating surface, mounted between the condenser 25 and the fan 38. It is of importance that I3 is separated from the conthe line 46 leading to tank 3|.

denser 25 so that the heat from 13 will not afiect the action of condenser 25. The tubing 13 is supplied with live steam from pipe 64 through pipe I4. A thermostatic trap 16, similar to trap 15, previously described, joins the end of 13 to Obviously, when steam is Supplied to nozzle 26, it will be simultaneously supplied to the tubing 13. Air flowing over the tube will cause condensation in 13 which condensate will be delivered through trap 16. to the tank 3|.

The quantities of water which are drawn from the various sources are of a varying nature. For

example, under some operating conditions, the water from 45 added to the water from the condenser 25 would be sufiicient to supply all makeup requirements. However, under other conditions, all the water available from the condenser 25,-from separator 45, condensate from coils l2, plus the steam condensed in the auxiliary condenser 13 is required. Since the supply and demand is so variable, an overflow pipe 11 is provided in tank 3| to prevent flooding.

It is apparent that by utilizing condensed steam throughout the system, troubles due to boiler scale are avoided. Except in rare cases, the water used in the locomotive is soft water naturally or by artificial means. Further, the water used in the cooling tower is, in effect, distilled water. Hence, the occurrence of troublesome boiler scale is avoided.

The system operates at a high vacuum, and in order to assure effective condenser action, provision is made-for purging. Air which will be brought in by the steam and any other air which may leak in will tend to collect in the upper tubes and discharge header 28 of the condenser 25. Upper tube 41 connects with the uppermost part of discharge header 28 where air and other gases to be purged normally collect. Tube 41 connects with air discharge pipe 48. The condensate in the bottom of discharge header 28 is led through trap 49 and joins pipe 48. The air and water then proceed to separating chamber 50. which separates and returns part of the water to the evaporator in a manner hereinafter described. The remainder of the water and air are drawn through pipe 5| by the combined action of the aspirators 36 and 31 in communication therewith to a second separator 52. The water-and some air then passes into the aspirator 36 and is discharged with the condenser water through pipe 32 and spray header 34. The air is drawn through pipe 53 into aspirator 31 and is similarly discharged with condenser water through spray header 35. Pump 30, as already described, supplies water from tank 3| to pipes 32 and 33, and the water quantities are adequate to make eflective the aspirator action. The system is, therefore, continually purged as long as its operation is carried on.

Separator 50 may take the simple form of a T-connection joining pipe 5| with the condenser leg of U-shaped trap 51. This connection may be placed at any point above the normal liquid level in the condenser leg of trap 51, so that there is always a vapor connection between the separator and the condenser.

The condenser is preferably mounted in an angular position, tilted in two directions, as shown in Fig. 1. This is important, because in train operation, as when proceeding around a curve, or upgrade, the condenser might otherwise be tilted to prevent gravity drain. By mounting the condenser at an angle in the manner illustrated, the position of the low point of the condenser will remain substantially the same at all times and assure drainage without interruption despite change in level of the car during ascent, descent or operation around curves.

Some of the water collected in separating chamber 50 is returned to the evaporator through.

U connection 51, for the purpose of maintaining an adequate supply of water in the evaporator, whenever diminution resulting from evaporation lowers the level beyond a predetermined minimum. The evaporator is divided into chambers 54 and 55 by a weir 56. The chamber 55 serves as a reservoir for collecting water and surface evaporation therefrom is continually carried on during the operation of the evaporator. The U connection 51 discharges into chamber 54. Due to the fact that water is constantly being evaporated from evaporator 5, it is obvious that in time there will be no overflow from chamber 55 into 54. Since water is continually being withdrawn in constant volume from chamber 54 by pump It, the level in chamber 54 will fall. The U connection is so designed that a certain height of water in chamber 54 plus the height of water in the evaporator leg of trap 51 plus the evaporator pressure will balance the condenser pressure plus the pressure of a certain height of water in the condenser leg of trap 51. As the height of water in 54 decreases, water will flow through the U connection from separator 50 to chamber 54 until the level in 54 rises to a point sufllcient again to equalize the pressures. Thus, the supply of water in evaporator I5 is automatically replenished, depending upon the rate of evaporation therein.

While the reservoir portion of the evaporator is shown divided into two chambers, it is obvious that only one chamber may be provided. Applicant prefers to divide the evaporator into two chambers to provide a storage of cold water which may be utilized for some time after the ejector action has been discontinued.

To prevent air from forcing its way through the spray headers and aspirators back into the system,'when pump 30 is not operating, valve 58 is provided in the pipe 5|. This valve is of the type which is normally held closed by a spring and which opens in response topressure exerted on a diaphragm, or bellows, operatively connected to the valve. Thus, the diaphragm of valve 58 acts responsive to the flow of water through aspirator 35, as indicated by the broken line connecting the two, so that when pump 30 operates, the resulting pressure will open 58, but when the pump stops, the valve simultaneously closes under the action of a spring. It .is apparent that an electrically operated valve or some type of check valve might be substituted for 58. Applicant presimple and inexpensive.

. point.

For operating the system, a supply of steam is provided from a suitable source. In train operation, steam may be supplied from a locomotive or central station and fed, preferably, through supply lines commonly used for supplying steam for winter heating, to the various cars equipped with air conditioning systems. Where single units are employed, a boiler or other generating means maybe combined with the system, but, in the car arrangement illustrated, wherein a plurality of air conditioning systems are employed, ,each of the cars I0, as shown in Fig. 3, obtains its steam supply from the common source or' locomotive boiler II. Steam enters pipe 59, which is suitably connected to a supply line leading from the locomotive. The steam then passes through regulating valve 60, blowofi valve 62 and pressure switch 63 before entering steam separator 45. The valve 60 is of the diaphragm type, operative responsive to steam pressure, as shown by dotted line 6|, and adapted to reduce the pressure of incoming steam to a predetermined Thus, steam may be supplied at pressures very much greater than that desired and valve 60 will tend to maintain the pressure entering the system at a constant value. If the pressure is above said value, the valve will tend to close, whereas, if it falls below a certain value, it will allow the passage of steam at full pressure. Safety valve 62 operates in the usual manner, and willblow off if for any reason steam enters beyond valve 60 above a desired pressure. ,Pressure switch 03 operated responsive to steam pressure changes whereby a drop in steam pressure below a predetermined minimum causes the switch to function to cut off the supply of steam and make inoperative the refrigeration apparatus. When the steam pressure again rises to a desired point, it will function to admit steam and if refrigeration is then desired, the apparatus will again become operative.

Steam separator 45 removes entrained water from the steam in the usual manner, thereby allowing only dry and saturated steam to proceed to ejector nozzle 26. Pipe 64 conveys the steam from separator 45 to nozzle 26, under control of valve 55. This valve is of the type in which a diaphragm operates the closure member in response to pressure exerted thereon. Further, the diaphragm is so constructed that at predetermined pressure, it will operate with a quick or snap action. That is, the valve, normallyheld closedby a spring, is adapted to be opened when a predetermined fluid pressure is exerted on the diaphragm. The diaphragm of valve 55 is connected by means of conduit 66 tothe pipe 64 at a point between valve 65 and separator 45. Pilot valve 61 is adapted, among other things, to operate under the control of pressure switch 63 to enable valve 65 to function. When the pressure of the entering steam falls below a predetermined minimum, the pressure switch 53 will cause pilot 61 to out off the pressure against the diaphragm of valve 65 and simultaneously open the pipe 66 to the atmosphere at 02 whereby steam trapped between valves 61 and 05 may escape, whereupon valve 65 will close and steam prevented from entering the system. When the steam pressure rises above the desiredpoint, the pressure switch will cause pilot, 61 to enable 55 to admit steam, provided the system is calling for refrigeration.' More particularly; valve 61 is adapted to be opened or closed in response to the expansion or contraction of a fluid contained in a bellows, An

steam to pass through the valve. When the cir-- cuit is broken, the bellows will contract, due to the cooling and contraction of the fluid therein,

and the pressure of an associated spring will cause the closure member to assume a closed position against the seat. While an electrical arrangement is employed for causing pilot 6'! to control valve 65, it is obvious that an air pressure system, for example, could be used with like effect to control valve 65.

The operation of the system depends upon the functioning of the components thereof, as individual units or systems of apparatus, and upon their cooperative interrelation responsive to any suitable system of control. Such control may be manual, partly automatic, or fully automatic. For purposes of illustration, the following description sets forth an illustrative method of operation under a control adapted for use in air conditioning an enclosure such as a railroad passenger car. It will be obvious that similar combinations of apparatus under analogous methods of control could be employed for other air conditioning and refrigeration purposes.

Fig. 2 shows an electrical control arrangement adapted to be employed in combination with the system of Fig. 1. Considering the control arrangement, binding posts I00 connect to a suitable source of generator current and binding posts IOI connect to a suitable battery source. 'Switch I02 enables connection to either of the battery or generator sources, and may interconnect the two. Switches I03, I04 and I05 connect respective circuits to various parts of the system, as will be hereinafter described.

Upon closing switch I 03, a circuit will obviously be completed for operating air conditioning fan 6. It is always desirable to have fan 6 operating whenever the car enclosure is being occupied. A circulation of air is desirable regardless of the necessity for air cooling or conditioning. As a result, even if the air conditioning apparatus becomes inoperative, or when the cooling apparatus is closed down, as under winter conditions, a circulation of air-will still be maintained. This air may be drawn from outdoors through dampers 8 or may be a combination of outdoor air and air from the enclosure admitted through dampers I0 and/or I9.

Assuming that the temperature in the enclosure is above a predetermined point, and air cooling and conditioning is desired, the system will be placed in operation provided it is ready to function safely and efliciently. Thus, thermostat 69, responsive to temperature changes in the enclosure, will first cause dampers I0 to open widely and dampers I9 to approach closed position. If the combination of fresh and return air is not sufliciently cool to lower the air temperature in the car, damper motor 20, under control of thermostat 60, will then close connection I06. Assuming that steam pressure in the pipe 59 is sufliciently high to close pressure switch 63, the following circuits will be completed. Switch I03, push button switch I01, which is closed by the conductor, in railroad operation, during the cooling and air conditioning season, connection I00 of damper motor 20, thermostat I08, located in the evaporator, pressure switch 63, winding of relay III, terminal II! and back to the switch.

The energization of the winding of relay III will cause its associated armature to be pulled up and make contact at II3, thereby closing the following circuits, assuming that hand switches H4 and I I5 are in closed position. Switch I05, contact II3, motor of fan 38, serving the cooling tower, switch H4 and back to switch I05. The other circuit under control of the relay III follows a path from switch I 05 to contact I I3, motor of condenser pump 30, switch II 5 and back to switch I05.

The completion of this circuit places pump 30 in operation, whereupon the aspirators 36 and 31 operate to purge the condenser of any accumulated gases in a manner hereinbefore described. When the pressure in the condenser 25 has been reduced to a predetermined'point (assuming that the system has been inoperative for some time), the pressure switch I09 will close, whereupon the following'circuit will be completed: Switch I03, push button switch I01, connection I 06 of damper motor 20, thermostat I08 located in the evaporator, pressure switch 63, condenser pressure switch I09, thermostat I I0 (in difiuser 24 or condenser 25) pilot valve 61 and back to switch I03.

Another circuit dependent upon the operation of damper motor 20 and the closing of connection I06 is as follows: Switch I03, push button switch I01, connection I06, thermostat H6 in the evaporator, winding of relay H1, terminals H8 and I I2, and back to switch I03.

The energization of the winding of relay II 1 causes its associated armature to pull up, thereby making contact at IIS and completing a circuit for the air conditioning pump as follows: Switch I04, contact II 9, motor of the air conditioning pump I6 and back to switch I04. g It is evident, therefore, that the plurality of circuits hereinabove described controls the operation of the system so that it will give desired refrigeration service only when temperature conditions are within predetermined limits and then only if the various devices forming-part of or appertaining to the system are in condition to function properly. Thus, by reference to the lower portion of Fig. 1, it may be noted that steam will not be admitted to ejector nozzle 26 unless certain prerequisites are met. First, it will be reduced to a desired pressure under control of valve 60. If valve 60 does not properly function, the pressure will still be lowered to the proper point by safety valve 62. Then, steam pressure switch 63 makes sure that the steam pressure is above the efiective point sufiicient to assure desired ejector action, and unless this pressure is above the prescribed point, pilot valve 61 will not open; consequently, steam valve 65 will remain closed.

Assuming, however, that the steam pressure is below the blow ofi point and above the minimum required for eificient ejector action, and assuming that pilot valve 61 is in condition to allow the passage of steam, the steam will pass through nozzle 26. The ejector action causes evaporation in evaporator I5. and the passage of steam will cause water vapor to be sucked from the evaporator and entrained and compressed by the steam. The mixture of steam and-vapor then proceeds to the condenser, the ejector nozzle and diffuser being so designed that efficient transit is assured, with no sacrifice to maximum evaporative or cooling effect upon the water in the evaporator. The mixture of steam and vapor is then liquefied in the condenser, the

liquid condensate draining to trap 49 and then to Separator 50. As already pointed out, air and other gases will rise to the upper tube 41 of the orated during the condensing and cooling tower process will drain from condenser well 42 into storage tank 3|, and the cycle will be repeated.

The cooled water in the evaporator is conveyed to cooling and dehumidification coils I2 by pump I6 and then returned to the evaporator in the simple cycle illustrated in Fig. 1. As already noted, outside air and/or return air will be cooled and dehumidified in passing over the cooling coils, and will then be discharged to the interior to be conditioned either alone or in combination with bypassed air. While the above is the normal method of operation during periods requiring cooling and conditioning, the

control arrangement shown more particularly cuits hereinbefore described. Included in this circuit is thermostat I08, located within evaporator I5, which will maintain a closed connection so long as the temperature of the cooling water in the evaporator is above a predetermined temperature. If the cooling water falls below the predetermined point, say 40? F., the thermostat will operate to break the electrical connection and hence, open the circuit. Further, pressure switch 63 is also included in the said circuit arrangement and will not allow the circuit to be completed unless steam at or above a minimum desired pressure is available.

The energization of relay III is dependent' upon closure of the connections under control of thermostat I08 and pressure switch 63, so that as soon as the relay becomes energized, the cooling tower fan and the condenser pump will start to operateand purging operations will immediately commence to clear thesystem. The fan will not be cut in unless hand switch H5 is in closed position and need not be cut in until the system is sufliciently purged. As soon as the condenser pressure has been reduced below a predetermined maximum, condenser pressure switch I09 will operate to close electrical contacts controlledthereby as will thermostat H0 located in diffuser 24, if the temperature of condenser is below a predetermined maximum. If desired, thermostat IIO ,may be located in the condenser well.

Pilot' valve 61 is directly under control of thermostat I08 in the evaporator, pressure switch 63,

pressure switch I09 in the condenser, and ther-- remained below the steam to the system, whereas, if one of these instruments records unfavorable conditions, the pilot valve will cause valve 65 to cut off the steam and make the system inoperative.

The air conditioner pump for circulating cooling water from the evaporator l5 to the cooling coils I2 is under primary control of the circuit whose completion is dependent upon the energization of relay"! IT. This relay will'be caused to energize only when thermostat H6 in the evaporator records a temperature below a predetermined maximum. 7 sirable to permit the circulation of warm water. It is only when the water temperature is below a certain point that cooling could be carried on and hence, thermostat H6 will break the circuit when the temperature rises above a desired level, but will permit circulation. to be carried on as long as the temperature is favorable to cooling.

The circuits are closely interrelated, so that a fault affecting one of them will influence the action of the others. For example, should fan 38 become inoperative, the temperature of the condenser water would soon rise to an undesirable level. Thermostat H would then respond to break the circuit, including pilot valve 61 and steam would be cut off, thus making the system inoperative. As a result, the ejectoraction would cease and the temperature in the evaporator quickly rise, especially under summer conditions, so that thermostat 6 would respond and break the circuit for the air conditioner pump, thereby preventing circulation of hot water to the cooler, and preventingiunduly heating up the water of the evaporator. If the fault were repaired, and the system restarted, the ejector action would be carried on with the air conditioner pump inoperative until the water was cooled to a sufiicient degree, and then only would thermostat I I complete the circuit for the air conditioner pump and allow circulation of cooling water.

Assuming, further, that the condenser pump became inoperative, the pressure in the condenser would soon cause switch I09 to break the circuit including pilot valve, and thus cut off steam from the system. So also, if the con denser water fed by the pump rose to an abnormal level, due to any cause. condenser thermostat H0 would break the circuit and cause pilot 6'! to cut off the steam from the system. Assuming the air conditioner pump broke down, the temperature of the water in the evaporator would tend to fall below the predetermined low limit, whereupon thermostat I08 would break all circuits except that for the air conditioner fan, and steam would be out ofi from the system, as well as cooling tower fan and condenser pump become inoperative.

Of course, if the temperature in the enclosure fell below the desired level, thermostat 69 would cause motor 20 to break connection I06, whereupon all of the circuits, with the exception of the air conditioner fan circuit, would be broken and the system become wholly inoperative. It is of note that if the temperature in the enclosure still desired limit, the thermostat would cause dampers Hlto close and damper Is to open, so that a maximum of air would be bypassed and a minimum sentthrough the coils which -might still be sufiiciently cold to cause cooling. It is manifest that space requirements in a railroad car, for example, are exceedingly exacting in that it is highly desirable to retain senger and service areas.

Obviously, it is not de-' the service or lavatory spaces.

the orthodox interior appearance of the car and utilize a minimumof useful space-in the pas- As a result, the combined condenser and cooling tower arrangement, including the copling tower fan, is positioned in the upper area of the car adjacent the roof, with air inlet and outlet so arranged that the installation is neither noticeable nor detracts from the utility of the floor or passenger accommodation areas. So also, the combination of heating coils, cooling coils, dampers and air conditioning fan may be positioned at one end of the car in an upper area thereof adjacent the roof and will similarly be out of the way and not affect the conventional appearance of the car interior. The evaporator, pumps and difiuser may be suitably arranged in the upper deck area of the car or may be suitably positioned in one of If desired, some of the equipment, such as the pumps and motors therefor, may be installed beneath the car.

No reservation is made as to the arrangement of the parts, their interconnection, or their method of operation, application, or interrelation.

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 the above 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. In a system of air conditioning for an enclosure, an evaporator, a condenser, and means for feeding condensate formed in the condenser to said evaporator responsive to changes in liquid level within the evaporator, said means comprising a hydrostatic trap in which condensate is collected to balance the difference in the pressures existing in the evaporator and condenser.

2. In a combination of apparatus of the character described, an evaporator, a condenser, steam ejector apparatus, means for supplying steam to the ejector apparatus for causing evaporation in the' evaporator, the steam ejector. apparatus discharging within the condenser, and means for supplying condensate from the condenser to the evaporator responsive to changes in liquid level therein said means comevaporator and another portion of the condensate to a circuit supplying liquid over the outer surfaces of the condenser.

4. In a system of the character described, an evaporator, a condenser, said evaporator and condenser normally operating at pressures below atmospheric, a circulating system for discharging liquid over the surfaces of said con-' denser, a first passageway for conveying fluid from said condenser to said evaporator, a second passageway for conveying fluid from said first passageway to said circulating system and means operative responsive to the cessation of flow of liquid in said circulating system for closing said second passageway.

5. In an air conditioning system, an air conditioning unit, an evaporator serving the unit, a regulating device operative responsive to temperature changes in the evaporator, a second regulating device operative responsive to changes in temperature within the area served by the air conditioning unit, and a pump under control of said devices, said pump being operative to supply a cold fluid from said evaporator to said unit only when the temperature in the evaporator is below a desired value, and the temperature within the area served by the unit is above a desired value.

6. In an air conditioning system, means for supplying a fluid to to injector, an evaporator in combination with the ejector, a condenser for receiving said fluid from the ejector and vapor from the evaporator, a regulating device operative responsive to changes in pressure within the evaporator, another regulating device operative responsive ,to temperature changes in the condenser, means operative responsive to said regulating devices for controlling the fiow of fluid to the ejector, said last means beingarranged to operate only when the pressure in the evaporator and the temperature in the condenser are below desired values.

7. In combination with a railroad car, a source of steam; an evaporator, an ejector communicating with said'evaporator, means for supplying steam from said source to the ejector. 1

means for controlling the pressure of steam supplied to the ejector responsive to changes in pressure of steam supplied from said source, and

means for cutting oil the steam to the ejector when the pressure falls below a predetermined point.

8. In a system of the character described, an evaporator, a condenser, a steam ejector between said evaporator and condenser, means for discharging liquid over the outer surfaces of said condenser, a first passageway for conveying liquid from said condenser to said evaporator, a second passagewaybetween said means and said first passageway, and means for closing said second passageway whenever said first mentioned means is inoperative.

9. In a system of the character described, an evaporator, a condenser, a steam ejector between said evaporator and said condenser, a circulating system for discharging liquid over the outer surfaces of said condenser, a water ejector in said circulating system, a first passageway for conveying liquid from said condenser to said evaporator, a second passageway for conveying liquid from'said first passageway to said water ejector, and means operative responsive to the cessation of liquid flow in said circulating system for closing said second passageway.

10. In a system of the character described, an evaporator, a condenser, a steam ejector between said evaporator and said condenser, a circulating system for discharging liquid over the outer surfaces of said condenser, thereby to effect a condensation of vapors therein, a separating chamber. a- Dassageway for conveying condensate and non-condensable gases from said condenser to said chamber, means for supplying a portion of condensate from said chamber to said evaporator, and means for supplying the remaining portion of said liquid and said non-condensable gases from said chambers to said circulating system.

11. In a system of the character described, an evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a circulating system for discharging liquid over the outer surfaces of said condenser, thereby to effect a condensation of. vapors therein, a

posed between said evaporator and said 0011- denser, a circulating system for discharging liquid over the outer surfaces of said condenser to efi'ect a condensationof vapors therein, a separating chammr, means for conveying liquid and noncondensable gases from said condenser to said chamber, means for supplying a portion of liquid from said chamber' to said evaporator, a water ejector in said circulating system, a passageway communicating with said chamber and said ejector, and means operative responsive to a cessation of liquid flow in said circulating system for closing said passageway.

13. In a system of the character described, an evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a circulating system for discharging liquid over the outer surfaces of said condenser to effect plying one portion of the condensate to said evaporator, means for supplying the remaining condensate to said circulating'system, and other means for augmenting the liquid in said circulating system.

14. In a system of air conditioning a source of steam, an evaporator, an injector means providing communication between said ejector and said source of steam for supplying steam from said source to said ejector, means providing communication between said evaporator and said ejector, means for controlling the pressure of steam supplied ,to the ejector responsive to changes in pressure of steam supplied from said source, and means for interrupting the supply of steam to the ejector when the steam pressure of said source falls below a predetermined point.

15.- In a system of the character described, an evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a source of steam serving said ejector, a circulating system for discharging liquid over the outer surfaces of said condenser to effect a condensation of vapors therein, and means including a second condenser for condensing steam from said source and for supplying the resultant condensate to said circulating system.

16. In a system of the character described, an evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a source .of steam, a circulating system for discharging liquid over the outer surfaces of said condenser to effect a condensation of vapors therein, means for supplying to said evaporator a portion of the condensate, means for supplying to said circulating system another portion of the condensate, and means including another condenser for condensing steam from said source and for supplying the resultant condensate to said circulating system.

17. In a system of the character described, an evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a source of steam serving said ejector, a circulating system for discharging liquid over the outer surfaces of said condenser to effect a condensation of vapors therein, and means including a second condenser for condensing steam from said source and for supplying the resultant condensate to said circulating system, and means for supplying to said circulating system moisture condensed by said evaporator.

18. In a system of the character described, an

evaporator, a condenser, a steam ejector interposed between said evaporator and said condenser, a source of steam serving said ejector, a circulating system for discharging liquid over the outer surfaces of said condenser to efl'ect a condensation of vapors therein, and means including a second condenser for condensing steam from said source and f or supplying at least a portion of the resultant condensate to the outer surfaces of said first-mentioned condenser.

. CARLYLE M. ASHLEY.

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