US2128021A

US2128021A - Refrigerating apparatus

Info

Publication number: US2128021A
Authority: US
Publication date: 1938-08-23
Anticipated expiration: 1955-08-23

Description

H. F. SMITH REFRIGERATING APPARATUS Aug. 23, 1938.

' Filed March 31', 19:54

2 Sheets-Sheet 1 hum d/ 5,

Aug. 23, 1938. H. F. SMITH 2,128,021

REFRIGERATING APPARATUS Filed March 31, 1934 2 Sheets-Sheet 2 Patented Aug. 23, 1938 I t I UNITED STATES PATENT OFFICE 2,128,021 BEFRIGERATING. APPARATUS Harry F. Smith, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application March 31, 1934, Serial No. 718,315

1's Claims. (Cl. 6211'7) This invention relates to refrigeration and the outlet of the evaporator and which tends to more particularly to the conditioning of air. throttle the valve 20 when the outlet pipe is cooled There is among the objects of this invention to below a predetermined temperature. This tends provide a method and apparatus for conditioning to prevent frost-back in the suction line. The

5 air in which the refrigerant liquefying unit may valve 20 is provided with an automatic control as 5 be operated at varying capacities or where drivis well known, which is set to maintain a refriging power therefor is available only periodically erant pressure in the evaporator corresponding andin which an efiicient holdover is provided as to a temperature slightly above 32? F. as long as an aid in conditioning the air while the refrigerthe thermostatic bulb does not throttle the valve ant liquefying unit lacks sufficient capacity. further. when the evaporator becomes sufiicient- 10 More specifically this invention is applicable to 1y filled with liquid refrigerant so that refrigeratmoving vehicles such as railway carsor the like ing tends to occur in the line I8, then the therwhere the refrigerant liquefying unit is driven by mostatic bulb 2| throttles the valve 20 and reenergy generatedduring the motion of the car and duces the amount of liquid refrigerant entering where the lique fying capacity of the unit or the the evaporator. If desired, an evaporated re- 15 availability of driving power varies due to variafrigerant h ott g ve 22 is placed in the $110- tions in th motion f th car, tion line which is controlled by a thermostatic Further objects and advantages of the present bulb 23 so that if frost-back occurs in pipe l8, invention will be apparent from the following deotw t st e p at of t Valve 20 scription reference being had to the accompanythen the valve 22 is throttled and thus reduces 0 ing drawings, wherein a preferred form of the the on e ect 01 t e iqu y unit on the present invention is clearly shown. evaporator.

In the drawings: The air is caused to flow over the evaporator Fig. 1 is a vertical cross-sectional view, somel6 by means of a blower or fan 24 havin its 25 What diagrammatic, of an apparatus embodying take connected with the compartment I 0, or with 25 my invention; the atmosphere outside of the car, or both. The Fig. 2 is a cross-sectional view taken along the air circulating capacity of fan 24 and the effective line 2-2 of Fig. 1; refrigerating area of the evaporator iii are so Fig. 3 is a horizontal diagrammatic view ofa proportioned with the various valves in the syscar showing a type of air flow which may be used; tem, so that when the air at summer temperature 30 Fig. 4 is a vertical cross-sectional view someflows over the evap r. t e Surfaces he what similar to Fig. 1 but showing a slightly modiare near but above 32 F. fied form of the invention. The refri era t liquefying unit I! is driven by In practicing my invention, the air' to be conener y ge er y e motion o e ea T 35 ditioned for the enclosure In of the car or the like d iving mea s t e o e may be either direct y 35 is brought into thermal contact with the air con connected to a wheel of the car, or it may be ditioning apparatus and is then discharged into driven by an e t c motor Supplied with electhe compartment It. If desired, two air condi tri it-y n r d y a e ator ven y the tioning units II and l2,substantially identical but Wheel. In the particulan'embodiment shown in 40 symmetrically arranged are placed at opposite Fig. 1, the unit is driven directly by the wheel 25 of 40 ends of the car in the upper portion thereof to the car. Thus a belt drive, or similar drive, 26 discharge oppositely directed streams of air l3 and cts the Wheel 25 W th the pu ley which 14 above the heads of persons seated in the seats in turn is connected by a belt drive 28 with the IS of the car. Any arrangement for circulating compressor 29 of the liquefying unit. The rethe air may be used, and this particular one is frigerant compressed by the compressor 29 is 45 shown by way of example- 1 discharged into the condenser 30, which may be The apparatus for conditioning air may include either air cooled or water cooled, and the liquefied a refrigerating system comprising a refrigerant refrigerant is delivered to the receiver 3|, from evaporator l6 and a refrigerant liquefying unit whence it flows through the line I8 to the evapo- I ll operatively connected with each other so that rator. The refrigerant liquefying unit l1 thus has 50 liquid refrigerant is circulated through the line l8 imparted thereto periods of excess refrigerating to the evaporator where the refrigerant is evapocapacity and periods of insufiicient refrigerating rated andreturns" through the line IS. A suitable capacity when the car travels at low speeds or expansion valve 20 is provided in the line I 8 which when it stops entirely. The evaporator I 6 has is controlled by a thermostatic bulb 2| placed at therefore likewise periods of excess refrigerating 55 capacity and periods of insufficient capacity with regard to the refrigerant flow therethrough. If desired, the drive between the wheel 25 and the compressor may include a constant speed automatic transmission which tends to drive the compressor at substantially constant speed regardless of the speed of the car.

A holdover system is placed in thermal exchange relation with the refrigerating system and more specifically with the evaporator I6 thereof. To this end, a volatile fluid such as water is placed in a closed holdover space from 'which air has been removed as completely as possible. This holdover space may include a thermal exchange holdover phase changing portion 32 in thermal exchange relationship with the evaporator and evaporative holdover phase changing position 33, properly insulated by insulation 34 and placed underneath the floor of the car.

The portion 32 may be placed in thermal exchange relationship with the evaporator through the medium of fins 35 through which the coils 36 at evaporator l6 pass. The upper ends of fins 35 are bent at 31 and are soldered or brazed to the floor 38 of the portion or chamber 32 of the holdover system. The evaporative portion 33 may be provided with evaporating surfaces or pads 39 and the two portions may be connected by a pipe 40 suitably insulated as indicated.

While the car is traveling at normal or high speeds, air is forced through the evaporator by the motor driven fan 24 with the openings 4| in fully opened condition. Normally such operation causes the refrigerating surfaces to be maintained near but above 32 F. After a certain period of operation the temperature in the compartment I 0 usually is reduced below a predetermined limit at which time the thermostatic bulb 42, acting through the bellows 43 actuates the shutters 44 to close openings 4| and open openings 4la to throttle the flow of air over the evaporator and thus reduce the thermal exchange relationship between the air and the evaporator. The air circulated by the fan 24 then flows through the bypass 45 substantially without any cooling action from the evaporator. Under these conditions, the refrigerating capacity of the system is such that the temperature of the refriger-' ating surfaces of evaporator I5 falls below 32 F.

because no heat from the air is applied thereto. This in turn reduces the temperature of the surfaces in the portions 32 below the freezing temperature of water vapor therein which thus changes phase on the inner surfaces of the portion 32. This change of phase of water vapor is accompanied by a. transfer of heat from the holdover fluid to the evaporator l6. Simultaneously water vapor is formed in the evaporative portion 33 to replace the vapor removed by change of phase in 32. As this action continues, the water in the portion 33 is frozen on the evaporative surface or 'pads 39, and thus a refrigerating holdover capacity is built. When the temperature of the compartment Ill rises, either because the refrigerating capacity of refrigerating systems is decreased due to a change in the motion of the car, or because the heat infiltration into the car raises the temperature thereof, the thermostatic bulb 42 opens the shutter 4| and closes the bypass 45 so that air is once more forced over the evaporator l6. When this occurs, the air is cooled either through the action of the refrigerating system or through a change of phase in the holdover fluid, or both. Thus if the car is stopped, heat travels from the air through the fins 35 to the holdover frozen in the heat from the air, the vapors are then driven downwardly through the pipe 40 to the portion 33 where they are condensed by the melting of ice on surfaces 39. The cooling action of the holdover thus continues as long as any ice remains in the holdover system. The total holdover capacity of the system is made sufiicient to cool the car during normal stops at stations.

If desired, a motor 50 is provided with a suitable clutch which connects the motor and dis-' connects the wheel drive to drive the compressor 29 with current from the station when the car stops for abnormally long periods of time such as at terminals or the like. The motor 50 is started and stopped by means of a switch 5| responsive to back pressures in line l9 or to temperatures in the room as preferred.

In the modification shown in Fig. 4 the parts which are similarly numbered are made substantially the same as in Fig. 1, with the exception that two pipes 40' and 40" connect the

portions

32 and 33 of the holdover system. The holdover system is not operated at a vacuum as in Fig. 1 but an inert gas, such as air, is permitted to remain therein so that the holdover system internal pressure is substantially equal to atmospheric pressure. A small blower 52 is placed in the pipe 40' and is driven by motor 53 under control of a switch 54. The fan or blower 52 circulates the air through the holdover system and thus causes the water vapor to be circulated with the air between the two portions of 32 and 33.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An air conditioning apparatus comprising a refrigerating system including a refrigerant evaporator and a refrigerant liquefying unit in operative relationship, means for selectively placing said evaporator in and out of thermal exchange relationship with the air to be conditioned, a holdover system in thermal exchange relationship with said evaporator, said holdover system including a thermal exchange holdover phase changing portion and an evaporative holdover phase changing portion connected to said first named portion, arranged to cause said holdover to add heat to said evaporator and remove heat from said evaporative'holdover phase changing portion during periods of excess capacity of said refrigerating system and to remove heat from the air during periods of insufficient capacity of said refrigerating system.

2. An air conditioning apparatus comprising a refrigerating ssytem including a refrigerant evaporator and a refrigerant liquefying unit in operative relationship, means for selectively placing said evaporator in and out of thermal exchange relationship with the air to be conditioned, a. holdover system in thermal exchange relationship with said evaporator, said holdover system including a thermal exchange holdover freezing portion and an evaporative holdover freezing portion connected to said first named portion, arranged to cause said holdover to add heat to said evaporator and remove heat from said evaporative holdover freezing portion during periods of excess capacity of said refrigerating system and to remove heat from the air portion 32. As this holdover melts and absorbs tion with a change of phase in said holdover during periods of insufficient capacity of said refrigerating system.

3. An air conditioning apparatus comprising a refrigerating system including a refrigerant evaporator and a refrigerant liquefying unit in operative relationship, means for selectively placing said evaporator in and out of thermal exchange relationship with the air to be conditioned, a holdover system in thermal exchange relationship with said evaporator, said holdover system including a thermal exchange holdover phase changing chamber in thermal exchange with said evaporator and an evaporative hold-- over phase changing chamber connected to said first named chamber, means for increasing and decreasing the air thermal exchange relationship between the air and said evaporator while said refrigerating system is operating, said holdover system being arranged to add heat to said evaporator from said evaporative holdover phase changing chamber when'said air thermal exchange relationship is decreasing and to remove heat from said air when the capacity of said refrigerating system is insufficient to condition said air.

vl. An air conditioning apparatus comprising a refrigerating system including a refrigerant evaporator in thermal exchange relationship with said air and a refrigerant liquefying unit operatively connected to said evaporator, means for imparting to said system periods of excess refrigerating capacity and periods of insufficient refrigerating capacity, a holdover system in thermal exchange relationship with said evaporator, saidholdover system including a thermal exchange holdover phase changing portion and an evaporative holdover phase changing portion connected to said first named portion, the relationship between said systems being such that heat is removed from said evaporative holdover phase changing portion with a change of phase in said holdover duringsaid periods of excess refrigerating capacity. 1

5. An air conditioning apparatus comprising a refrigerating system including a refrigerant evaporator in thermal exchange relationship with said air and a refrigerant liquefying unit operatively connected to said evaporator, means for imparting to said system periods of excess refrigerating capacity and periods of insufficient refrigerating capacity,'means for increasing and decreasing the air thermal exchange relationship between the air and said evaporator during said periods of excess refrigerating capacity, a holdover system in thermal exchange relationship with said evaporator, said holdover system including a thermal exchange holdover phase changing portion-and an evaporative holdover phase changing portion connected to said first named portion, the relationship between said systems being such that heat is removed from said evaporat ive holdover phase changing porduring said periods of excess refrigerating capacity, while said air thermal exchange relationship is decreasing and to removeheat from said air during said periods of insufficient refrigerat ing capacity.

6. A car, an air conditioning apparatus for said car, a refrigerating system including a refrigerant evaporator in thermal exchange relationship with said air and a refrigerant liquefying unit operatively connected to said evaporator, means for operating said refrigerant liquefying unit by energy generated during motion and means for condensing vapor of said fluid while said evaporator is throttled, and means for evaporating said condensed fluid and cooling said air while said refrigerating system is below refrigerating capacity because of insuificient motion of said car.

'1. A car, an air conditioning apparatus for said car, a refrigerating system including a refrigerant evaporator in thermal exchange relationship with said air and a refrigerant liquefying unit operatively connected to said evaporator, means for operating said refrigerant liquefying unit by energy generated during motion of said car, means for throttling the cooling effect of said evaporator below the refrigerating capacity of said system while said car is in motion, a holdover system including a volatile fluid and means for condensing vapor of said fluid while said evaporator is throttled, an inert gas in said hold-. over system and means for evaporating said condensed fluid and cooling said air while said refrigerating system is below refrigerating capacity because of insuiflcient motion of said car.

8. A car, an air conditioning apparatus for said car, a refrigerating system including a refrigerant evaporator in thermal exchange relationship with said air and a refrigerantliquefying unit operatively connected to said evaporator, means for operating said refrigerant liquefying unit by energy generated during motion of said car, means for throttling the cooling effect of said evaporator below the refrigerating capacity of said system while said car is in motion, a holdover system including a volatile fluid and means-for condensing vapor of said fluid while said evaporator is throttled, an inert gas in said holdover system means .for positively circulating said gas and means for orator and an insulated evaporative portion andin which heat exchange portion said fluid changes phase with loss of heat to said evaporator when said throttling means is operative and changes phase with absorption of heat when said liquefying unit lacks sufllcient refrigerating capacity and in which evaporative portion said fluid changes phase to supply and withdraw fluid from said other portion.

10. The method of conditioning air or the like which comprises thermally exchanging heat between said air and an evaporating refrigerant, reliquefying said refrigerant for re-use at rates above and below the requirements for conditioning said air, periodically throttling the exchange of heat between said air and refrigerant and simultaneously changing two phases of a volatile fluid including a vapor phase change by the removal of heat from said fluid into said refrigerant, and changing the phases of said fluid with addition of heat from said air to said fluid while 76 said reliquefying rate is below the requirements for conditioning said air.

11. An air conditioning apparatus comprising a refrigerating system including a refrigerant evaporator and a refrigerant liquefying unit in operative relationship, means for selectively placing said evaporator in and out of thermal exchange relationship with the air to be conditioned, a holdover system in thermal exchange relationship with said evaporator; said holdover system including a substance to be frozen by the change in vapor phase of said substance during periods of excess capacity of said refrigerating system and melted during periods of insufiicient capacity of said refrigerating system.

12. An air conditioning apparatus comprising a primary refrigerating system and a holdover system, said primary refrigerating system including means for cooling air and for cooling a first portion of said holdover system, said holdover system including said first portion and a second portion below said first portion and means for flowing a volatile secondary refrigerant between said portions, said volatile secondary refrigerant changing at least its vapor phase in said first portion by introducing heat into said primary refrigerating system during periods of activity of said primary refrigerating system and by removing heat from air during periods of less activity of said primary refrigerating system, said volatile secondary refrigerant changing at least its vapor phase in said second portion substantially concurrently with the vapor phase changes in said first portion.

13. A refrigerating apparatus comprising means to be cooled, a primary refrigerating system and a holdover system, said primary refrigerating system including a cooling member for said means to be cooled, said holdover system including a first portion to be cooled by said primary refrigerating system, a second portion connected to said first portion and means for flowing a volatile secondary refrigerant between said portions, said primary refrigerating system having periods of excess refrigerating capacity and periods of insuflicient refrigerating capacity, said secondary refrigerant changing at least its vapor phase in said first portion and to its solid phase in said second portion by introducing heat into said primary refrigerating, system during said periods of excess refrigerating capacity and changing at least to its vapor phase in said first portion and from its solid phase in said second portion during said periods of insufiicient refrigerating capacity.

14. An apparatus in accordance with claim 13, in which said primary refrigerating system is controlled in accordance with conditions of said means to be cooled.

15. An apparatus in accordance with claim 13, in which said holdover system is controlled in accordance with conditions of said means to be cooled.

16. In combination, a first evaporator, a second evaporator, heat radiating fins each in thermal exchange relationship with both of said evaporators, means for supplying refrigerant to said first evaporator, means for independently supplying refrigerant to said second evaporator, and means for circulating air to be conditioned over said heat radiating fins whereby either evaporator may cool said air independently of the other evaporator.

17. In combination, a first evaporator, a second evaporator, heat radiating fins each in thermal exchange relationship with both of said evaporators, means for supplying refrigerant to said first evaporator, means for independently supplying refrigerant to said second evaporator, means for circulating air to be conditioned over said heat radiating fins, and means for controlling the fiow of air over said heat radiating fins whereby either evaporator may cool said air independently of the other evaporator.

18. In combination, a first heat exchange member, a second heat exchange member, heat exchange fins each -in thermal exchange relationship with both of said members, means for supplying an attemporating medium to said first member, means for independently supplying an attemporating medium to said second member, and means for circulating air to be conditioned over said heat exchange fins whereby either of said heat exchange members may condition air independently of the other heat exchange member.

HARRY F. SMITH.