AUTOMOTIVE AIR CONDITIONING APPARATUS
United States Patent 3823573
For use in an automotive air conditioning apparatus, a compressor device which functions with a typical condenser and evaporator wherein the gas from the evaporator is introduced to a double acting piston and cylinder arrangement exhausted by a check valved conduit which then delivers the refrigerant gas at an elevated pressure to a water jacket heat exchanger. Preferably, the heat exchanger utilized water in the cooling system of the vehicle. The refrigerant is then delivered to a double acting fluid pump motor which is connected to the first pump. The refrigerant which has been raised in enthalpy is introduced to the fluid pump motor which is connected by means of a piston rod to the pump previously mentioned. After energy is taken from the refrigerant by the fluid pump motor, it is then supplied by a conduit to a typical condenser for cooling to the liquid state for transfer to the evaporator to repeat the cooling cycle.
US Patent References:
Refrigeration machine
Russell - May 1953 - 2637981
Refrigeration system with refrigerant operated pump
Wood - June 1961 - 2986898
Refrigeration system
Hoop - June 1961 - 2986907
Refrigeration system
Rogers - July 1961 - 2991632
Combustion driven pump
Carleton - January 1968 - 3361338
Refrigeration machine
Russell - May 1953 - 2637981
Refrigeration system with refrigerant operated pump
Wood - June 1961 - 2986898
Refrigeration system
Hoop - June 1961 - 2986907
Refrigeration system
Rogers - July 1961 - 2991632
Combustion driven pump
Carleton - January 1968 - 3361338
Application Number:
05/342189
Publication Date:
07/16/1974
Filing Date:
03/16/1973
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
62/243, 62/498, 62/79, 62/467, 62/116
International Classes:
F04B13/02; F04B35/00; F25B27/02; F04B13/00; F25B27/02
Field of Search:
62/79,238,116,498,243,467
US Patent References:
| 3710586 | REFRIGERATION SYSTEM WITH FLUID TRANSFORMER FOR CONTROLLING REGRIGERANT FLOW | January 1973 | Maudlin |
Primary Examiner:
Wye, William J.
Attorney, Agent or Firm:
Gunn, Donald
Claims:
I claim
1. A compressor for use with air conditioning systems typified by the sort found in automobiles which make available heated water as a heating medium, comprising:
2. The apparatus of claim 1 wherein said first and second pump means are assembled in a single housing to comprise a sealed unit.
3. The apparatus of claim 1 wherein said pump means has
4. The apparatus of claim 3 wherein said pump means is double acting and said valves intake at one end while expelling at the other end.
5. The apparatus of claim 1 wherein said second pump means has
6. The apparatus of claim 5 wherein said second pump means is double acting and said valves cooperatively intake at one end while expelling refrigerant at the other end.
7. The apparatus of claim 5 including a piston rod connected to said piston and to a piston in said pump means which causes said pump means to operate in unison.
8. The apparatus of claim 7 including a third pump means operated by said piston rod and which has an inlet connected to a source of liquid refrigerant and an outlet connected to deliver refrigerant downstream of said pump means.
1. A compressor for use with air conditioning systems typified by the sort found in automobiles which make available heated water as a heating medium, comprising:
2. The apparatus of claim 1 wherein said first and second pump means are assembled in a single housing to comprise a sealed unit.
3. The apparatus of claim 1 wherein said pump means has
4. The apparatus of claim 3 wherein said pump means is double acting and said valves intake at one end while expelling at the other end.
5. The apparatus of claim 1 wherein said second pump means has
6. The apparatus of claim 5 wherein said second pump means is double acting and said valves cooperatively intake at one end while expelling refrigerant at the other end.
7. The apparatus of claim 5 including a piston rod connected to said piston and to a piston in said pump means which causes said pump means to operate in unison.
8. The apparatus of claim 7 including a third pump means operated by said piston rod and which has an inlet connected to a source of liquid refrigerant and an outlet connected to deliver refrigerant downstream of said pump means.
Description:
BACKGROUND OF THE INVENTION
In automotive air conditioning equipment, two types of compressors are used in most models. One type of compressor utilizes a piston and cylinder arrangement. By way of example, the Ford Motor Company incorporates such equipment with the factory installed air conditioning equipment in cars sold by that firm. By way of contrast, the General Motors Corporation uses a rotary compressor. Both types of compressors exemplify compressors which have been found commonly in the automotive air conditioning equipment for the last several years in that they all incorporate a shaft which is driven by belt, chain or otherwise from the engine crank shaft. In other words, they require power taken from the rotating engine to compress the refrigerant as a portion of the air conditioning equipment. By way of contrast, the present invention is directed to a device which compresses the refrigerant by using power which is in the water in the automotive cooling system. The power in the coolant is found in the form of water at elevated temperatures. The water may run in the vicinity of 175° for automobiles with thermostats which are set relatively low to as much as 230° or so for the newer automobiles wherein the coolant system is pressurized to about 15 psi above atmospheric pressure. As a rule of thumb, an increase of 1 psi above atmospheric usually provides about 4° increase in the boiling point of the water so that it is possible to exceed the boiling temperature of water in cooling systems. A substantial amount of energy is rejected to atmosphere through the radiator.
The device of the present invention takes energy from the water in the cooling system and converts it into energy of a form suitable for compressing the refrigerant in the air conditioning system. This thus removes energy which is ordinarily rejected to the atmosphere in all other cases. Moreover, it frees the engine of a power robbing rotative device which is normally connected by means of a drive belt or chain. In further particular, it is advantageous in that rotating shafts are avoided and consequently, the device is simplier to construct and less likely to failure inasmuch as seals around rotating shafts are difficult to maintain throughout the life of an automobile. The unit is therefore totally sealed and it is submitted that maintenance is reduced.
SUMMARY OF THE PRESENT INVENTION
The present invention is summarized as being a type of compressor for use in automotive air conditioning systems. The compressor can be used with a typical condenser and evaporator. The device includes a piston pump and a fluid driven piston motor connected to the pump by a common push rod. The rod is fully sealed within the equipment and no moving parts are exposed or require seals. The fluid pump is provided with the heat laden gas from the evaporator and the gas is introduced on both sides by means of check valves which check valves are suitably arranged to pressurize the low pressure gas from the evaporator. The pressure is raised. The conduit for the gas communicating from the fluid pump passes through a heat exchanger where the heating medium is water in the cooling system of the engine. It emerges from the heat exchanger and is then delivered to a fluid motor. The fluid motor incorporates a piston having a connecting rod connected to the pump above metioned. By means of suitable timing on the valving arrangement, the piston is driven to and fro by the refrigerant gas which has had energy added by the heat exchanger. As the piston mmoves in one direction, it expels the refrigerant gas from the opposite side. The gas, when expelled, is supplied through a line to the condenser where the cycle is repeated.
BRIEF DESCRIPTION OF THE DRAWINGS
The single view is a schematic connective diagram of the compressor of the present invention with certain portions of the mechanical structure broken away to illustrate internal details of construction and further showing a manner of connecting the compressor with a condenser and evaporator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawing, the numeral 10 identifies the compressor of the present invention. It is connected in circuit with typical or conventional automotive air conditioning equipment. By that reference, attention is directed to a typical condenser and evaporator. They are not shown inasmuch as their construction is believed to be notorious and well known. The numeral 12 identifies a conduit which is input to the compressor equipment 10 from an evaporator. The conduit supplies the gas from the evaporator after it has absorbed heat. Normally, it is in vapor form. The numeral 14 identifies a second conduit which connects between the condenser and the evaporator. At that point, the refrigerant which flows in the system is ordinarily liquid rather than gas. It normally has minimum heat content. The conduit 14 is symbollically represented in the drawing and it will be appreciated that it is relatively small in comparison with the conduit 12 which conducts a gas. The numeral 16 identifies the output conduit of the compressor of the present invention which extends to a condenser. The conduit 16 delivers the highly pressurized gas to the condenser for cooling and reliquification.
The conduit 12 forks into two branches at 20 and 22. The two branches are input to opposite ends of a cylinder 24 which has a reciprocating piston 26 located therein. A double acting arrangement is provided wherein the branches 20 and 22 open through appropriately positioned check valves 28 and 30. Additionally, the numerals 32 and 34 identify check valves which connect with conduits 36 and 38 which merge together in a conduit 40 exhausting the cylinder 24. The conduits 36 and 38 connect to the opposite ends of the cylinder. Thus, the refrigerant is introduced into both ends of the chamber and is exhausted from both ends of the chamber. Dependent on the motion of the piston 26, fluid is introduced into one end as pressure is dropped within that end resulting from movement of the piston away from that end and the pressure is likewise raised in the other end of the cylinder 24 and the refrigerant is expelled from that end into the pipe 40.
The pipe 40 is then input to a heat exchanger 42. The heat exchanger has water from the engine cooling system introduced to a conduit or pipe at 44. The water flows through the heat exchanger and out through a conduit 46. The water forms a jacket around the conduit 40 which conduit extends to two branches, 46 and 48, indicated in the drawings. The branches 46 and 48 open into opposite ends of a fluid motor 50 which includes a cylindrical chamber and a piston 52 within the chamber. The piston 52 is connected by means of a piston rod 54 to the piston 26 described previously. It extends through a connecting tubular member 56 between the motor 50 and the pump 24. The piston rod 54 is found between the two pistons. In addition, an extension 58 is attached on the right hand side of the piston 26 and extends into a tightly fitting cylindrical hollow member at 60. The hollow member 60 is communicated with the pipe 14 through a check valve 62. An additional check valve 64 is located in the conduit 14 prior to the point where the conduit 14 connects with the conduit 40. The check valves are so arranged that liquid is introduced from the conduit 14 past the check valve 62 and the only exit permitted to that liquid is through the check valve 64.
The construction of the piston rod and associated piston should be considered. The two pistons, being connected on a common rod, have the same stroke and to this end, the internal chambers in which they are positioned are preferably approximately equal in length. They, of course, can differ in diameter which difference is inconsequental.
It will be observed that the cylinders 24 and 50 are joined by the tubular member 56. The piston rods slides in the tubular member 56. Preferably, some effort at preventing leakage along the piston rod 54 is made such as the incorporation of an O-ring seal or Chevron type packing within the tubular member 56. However, the use of such equipment is not mandatory in the sense that leakage along the piston rod 54 in either direction carries refrigerant to different parts of the system but does not permit its escape. The same is also true with the rod extension 58. It extends into the hollow tubular member 60. Preferably, O-rings or other seal rings are incorporated between the piston rod 58 and the surrounding hollow chamber. The reciprocating rod 58 serves as a pump for liquid refrigerant. It is a single acting pump which pumps on movement to the right of the single view and is recharged on movement to the left by drawing liquid through the check valve 62. The member 58 is exaggerated in scale. As will be noted hereinafter, the volume of liquid to be pumped is measurably smaller than the volume of gaseous refrigerant to be pumped by the piston 26.
The numerals 66 and 68 identify branch pipes communicating from the fluid motor 50 connecting with the outlet conduit 16. They connect with opposite ends of the motor 50. Introduction of refrigerant gas into the fluid motor 50 is controlled by means of two shuttle valves 70 and 72. The shuttle valves 70 and 72 move to block the respective conduits which are arranged immediately adjacent thereto. Considering just one of them for sake of illustration, the branch conduit 48 opens to one side of the piston 52. As illustrated, this conduit to open to the chamber within the cylinder 50. It is open at a time when the piston is moving away from the opening so that a drop in pressure tends to draw gas through the conduit 48 into the fluid motor 50. The shuttle valve 70 moves downwardly when the piston 52 reaches the extreme end of its travel at the right hand end of the drawing. The shuttle valves 70 and 72 are thus switched in position at the end of each stroke. That is to say, when the piston 52 arrives at the extremity of movement at both ends, the valves are switched in position. The movement of the shuttle valves 70 and 72 is upwardly and downwardly guided in the slotted construction illustrated in the drawings. The shuttle valves 70 and 72 differ in that the latter has an opening which spans the piston rod. The opening is preferably an elongate slot so that the piston rod passes through the shuttle valve without altering operation of the shuttle valve. The shuttle valves are operated by movement of the pistons and piston rod through means of a power take off mechanism which is not shown in the drawings. It is believed that an arrangement for operation of the shuttle valves of this sort is readily known by those skilled in the art. The significant point is that the shuttle valves control the introduction and exhaustion of refrigerant from the fluid motor 50 and that they are further operated when the piston 52 arrives at both extremities of movement.
To this juncture, the apparatus has been described. Its operation will be considered next. It will be presumed that a typical refrigerant such as Freon R-12 will be used. This is the refrigerant found in most automotive air conditioning system.
When the piston 26 reciprocates to and fro, it displaces gas arriving from the evaporator. As it moves in one direction, it tends to draw gas in one side of the chamber while compressing gas from the evaporator on the other side of the piston. The check valves are arranged so that the compressed gas is forced from the cylinder 24 into the conduit 40. It is made double acting and operates on both strokes. By way of example, the gas entering the compressor of the present invention is typically in the gaseous phase at about 70° F. having a pressure of about 30 psi. The vapor pressure is about 70 psi for the common refrigerant used in most automobiles.
The pump 58 at this time will be observed to be injecting liquid or near liquid phase refrigerant. At the point where the liquid is introduced, it is believed that the gas is normally in a vapor phase and is super heated. The liquid phase refrigerant which is compressed by the pump 58 and introduced in small quantities into the conduit 40 tends to convert the gas flowing in the conduit 40 through the heat exchanger to a saturated vapor. This tends to increase the density of the gas past the point of introduction. This results in a temperature drop and a pressure increase or volume increase. As will be observed, an increase in volume is prevented by the unyielding construction so that the pressure increases markedly. The pumped liquid volume is about 1/1600 of the pumped gas volume.
In the routine opreation of an automobile, the engine cooling system operates at temperatures typically controlled by a thermostat. In the winter time, the temperatures may sag significantly, but the air conditioning equipment of the present invention is normally not operated in the winter time. In the summer time, temperatures in the range of 180° to about 230° are readily achieved. The heat exchanger thus raises the temperature of the saturated gas in vapor phase to about 180°. At about 180° R-12 Freon refrigerant has a saturated vapor pressure of about 550 psi. Thus, the conduit 40 upon emerging from the heat exchanger delivers refrigerant in the vapor phase to the fluid motor 50 at about 550 psi and at about 180° F. The gas which is introduced into the fluid motor 50 surrenders energy and thus drops in pressure. It drops from about 550 psi to about 200 or 300 psi. There may or may not be a drop in temperature. The exhaust gas from the fluid motor 50 is then transferred to the condenser by the conduit 16 which extends from the present invention to the cooperating equipment. At this juncture, the gas is still typically a saturated vapor phase fluid. At the condenser, the high pressure vapor phase fluid is cooled from the vapor phase to liquid and a commensurate drop in pressure is experienced. The refrigerant then goes from the condenser to the evaporator where the pressure is lowered again at the expansion valve to enable the refrigerant to change phases from liquid to vapor thereby absorbing heat and the cycle is repeated.
If different refrigerants are used, the exemplary pressures and temperatures noted above may be altered, however, the operation will be similar.
The apparatus of the present invention has several significant advantages not the least of which is that it does not take any power from the crank shaft of the engine. This freedom of a rotative power source thus enables the compressor of the present invention to be mounted under the hood in the traditional manner or it can be located elsewhere at a more convenient location. The device tends to be more efficient and operate better when the water supplied from the engine cooling system is hotter. Thus, as the cooling water becomes hotter, more energy is imparted to the refrigerant in the heat exchanger causing the pump to operate with greater power. Since it removes heat energy from the cooling water, it actually tends to prevent the overheating of the engine cooling system. A significant factor is that the unit is entirely sealed and has no protruding or external shafts which require seals, magnetic clutches and the like. In addition, it has a minimum of moving parts and the parts which do move are totally and fully located within the apparatus and their mechanical life should be great by virtue of this protection.
As a matter of convenience, the heat exchanger 42 may be a separate entity remote from the radiator for cooling the engine or the heat exchanger 42 may be incorporated on the inside of the cooling system such as the point of introduction of the hot water into the radiator. A common housing encloses both pumps and has no projecting shafts.
The foregoing is directed to the preferred embodiment of the present invention but the scope thereof is determined by the claims which are as follows.
In automotive air conditioning equipment, two types of compressors are used in most models. One type of compressor utilizes a piston and cylinder arrangement. By way of example, the Ford Motor Company incorporates such equipment with the factory installed air conditioning equipment in cars sold by that firm. By way of contrast, the General Motors Corporation uses a rotary compressor. Both types of compressors exemplify compressors which have been found commonly in the automotive air conditioning equipment for the last several years in that they all incorporate a shaft which is driven by belt, chain or otherwise from the engine crank shaft. In other words, they require power taken from the rotating engine to compress the refrigerant as a portion of the air conditioning equipment. By way of contrast, the present invention is directed to a device which compresses the refrigerant by using power which is in the water in the automotive cooling system. The power in the coolant is found in the form of water at elevated temperatures. The water may run in the vicinity of 175° for automobiles with thermostats which are set relatively low to as much as 230° or so for the newer automobiles wherein the coolant system is pressurized to about 15 psi above atmospheric pressure. As a rule of thumb, an increase of 1 psi above atmospheric usually provides about 4° increase in the boiling point of the water so that it is possible to exceed the boiling temperature of water in cooling systems. A substantial amount of energy is rejected to atmosphere through the radiator.
The device of the present invention takes energy from the water in the cooling system and converts it into energy of a form suitable for compressing the refrigerant in the air conditioning system. This thus removes energy which is ordinarily rejected to the atmosphere in all other cases. Moreover, it frees the engine of a power robbing rotative device which is normally connected by means of a drive belt or chain. In further particular, it is advantageous in that rotating shafts are avoided and consequently, the device is simplier to construct and less likely to failure inasmuch as seals around rotating shafts are difficult to maintain throughout the life of an automobile. The unit is therefore totally sealed and it is submitted that maintenance is reduced.
SUMMARY OF THE PRESENT INVENTION
The present invention is summarized as being a type of compressor for use in automotive air conditioning systems. The compressor can be used with a typical condenser and evaporator. The device includes a piston pump and a fluid driven piston motor connected to the pump by a common push rod. The rod is fully sealed within the equipment and no moving parts are exposed or require seals. The fluid pump is provided with the heat laden gas from the evaporator and the gas is introduced on both sides by means of check valves which check valves are suitably arranged to pressurize the low pressure gas from the evaporator. The pressure is raised. The conduit for the gas communicating from the fluid pump passes through a heat exchanger where the heating medium is water in the cooling system of the engine. It emerges from the heat exchanger and is then delivered to a fluid motor. The fluid motor incorporates a piston having a connecting rod connected to the pump above metioned. By means of suitable timing on the valving arrangement, the piston is driven to and fro by the refrigerant gas which has had energy added by the heat exchanger. As the piston mmoves in one direction, it expels the refrigerant gas from the opposite side. The gas, when expelled, is supplied through a line to the condenser where the cycle is repeated.
BRIEF DESCRIPTION OF THE DRAWINGS
The single view is a schematic connective diagram of the compressor of the present invention with certain portions of the mechanical structure broken away to illustrate internal details of construction and further showing a manner of connecting the compressor with a condenser and evaporator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawing, the numeral 10 identifies the compressor of the present invention. It is connected in circuit with typical or conventional automotive air conditioning equipment. By that reference, attention is directed to a typical condenser and evaporator. They are not shown inasmuch as their construction is believed to be notorious and well known. The numeral 12 identifies a conduit which is input to the compressor equipment 10 from an evaporator. The conduit supplies the gas from the evaporator after it has absorbed heat. Normally, it is in vapor form. The numeral 14 identifies a second conduit which connects between the condenser and the evaporator. At that point, the refrigerant which flows in the system is ordinarily liquid rather than gas. It normally has minimum heat content. The conduit 14 is symbollically represented in the drawing and it will be appreciated that it is relatively small in comparison with the conduit 12 which conducts a gas. The numeral 16 identifies the output conduit of the compressor of the present invention which extends to a condenser. The conduit 16 delivers the highly pressurized gas to the condenser for cooling and reliquification.
The conduit 12 forks into two branches at 20 and 22. The two branches are input to opposite ends of a cylinder 24 which has a reciprocating piston 26 located therein. A double acting arrangement is provided wherein the branches 20 and 22 open through appropriately positioned check valves 28 and 30. Additionally, the numerals 32 and 34 identify check valves which connect with conduits 36 and 38 which merge together in a conduit 40 exhausting the cylinder 24. The conduits 36 and 38 connect to the opposite ends of the cylinder. Thus, the refrigerant is introduced into both ends of the chamber and is exhausted from both ends of the chamber. Dependent on the motion of the piston 26, fluid is introduced into one end as pressure is dropped within that end resulting from movement of the piston away from that end and the pressure is likewise raised in the other end of the cylinder 24 and the refrigerant is expelled from that end into the pipe 40.
The pipe 40 is then input to a heat exchanger 42. The heat exchanger has water from the engine cooling system introduced to a conduit or pipe at 44. The water flows through the heat exchanger and out through a conduit 46. The water forms a jacket around the conduit 40 which conduit extends to two branches, 46 and 48, indicated in the drawings. The branches 46 and 48 open into opposite ends of a fluid motor 50 which includes a cylindrical chamber and a piston 52 within the chamber. The piston 52 is connected by means of a piston rod 54 to the piston 26 described previously. It extends through a connecting tubular member 56 between the motor 50 and the pump 24. The piston rod 54 is found between the two pistons. In addition, an extension 58 is attached on the right hand side of the piston 26 and extends into a tightly fitting cylindrical hollow member at 60. The hollow member 60 is communicated with the pipe 14 through a check valve 62. An additional check valve 64 is located in the conduit 14 prior to the point where the conduit 14 connects with the conduit 40. The check valves are so arranged that liquid is introduced from the conduit 14 past the check valve 62 and the only exit permitted to that liquid is through the check valve 64.
The construction of the piston rod and associated piston should be considered. The two pistons, being connected on a common rod, have the same stroke and to this end, the internal chambers in which they are positioned are preferably approximately equal in length. They, of course, can differ in diameter which difference is inconsequental.
It will be observed that the cylinders 24 and 50 are joined by the tubular member 56. The piston rods slides in the tubular member 56. Preferably, some effort at preventing leakage along the piston rod 54 is made such as the incorporation of an O-ring seal or Chevron type packing within the tubular member 56. However, the use of such equipment is not mandatory in the sense that leakage along the piston rod 54 in either direction carries refrigerant to different parts of the system but does not permit its escape. The same is also true with the rod extension 58. It extends into the hollow tubular member 60. Preferably, O-rings or other seal rings are incorporated between the piston rod 58 and the surrounding hollow chamber. The reciprocating rod 58 serves as a pump for liquid refrigerant. It is a single acting pump which pumps on movement to the right of the single view and is recharged on movement to the left by drawing liquid through the check valve 62. The member 58 is exaggerated in scale. As will be noted hereinafter, the volume of liquid to be pumped is measurably smaller than the volume of gaseous refrigerant to be pumped by the piston 26.
The numerals 66 and 68 identify branch pipes communicating from the fluid motor 50 connecting with the outlet conduit 16. They connect with opposite ends of the motor 50. Introduction of refrigerant gas into the fluid motor 50 is controlled by means of two shuttle valves 70 and 72. The shuttle valves 70 and 72 move to block the respective conduits which are arranged immediately adjacent thereto. Considering just one of them for sake of illustration, the branch conduit 48 opens to one side of the piston 52. As illustrated, this conduit to open to the chamber within the cylinder 50. It is open at a time when the piston is moving away from the opening so that a drop in pressure tends to draw gas through the conduit 48 into the fluid motor 50. The shuttle valve 70 moves downwardly when the piston 52 reaches the extreme end of its travel at the right hand end of the drawing. The shuttle valves 70 and 72 are thus switched in position at the end of each stroke. That is to say, when the piston 52 arrives at the extremity of movement at both ends, the valves are switched in position. The movement of the shuttle valves 70 and 72 is upwardly and downwardly guided in the slotted construction illustrated in the drawings. The shuttle valves 70 and 72 differ in that the latter has an opening which spans the piston rod. The opening is preferably an elongate slot so that the piston rod passes through the shuttle valve without altering operation of the shuttle valve. The shuttle valves are operated by movement of the pistons and piston rod through means of a power take off mechanism which is not shown in the drawings. It is believed that an arrangement for operation of the shuttle valves of this sort is readily known by those skilled in the art. The significant point is that the shuttle valves control the introduction and exhaustion of refrigerant from the fluid motor 50 and that they are further operated when the piston 52 arrives at both extremities of movement.
To this juncture, the apparatus has been described. Its operation will be considered next. It will be presumed that a typical refrigerant such as Freon R-12 will be used. This is the refrigerant found in most automotive air conditioning system.
When the piston 26 reciprocates to and fro, it displaces gas arriving from the evaporator. As it moves in one direction, it tends to draw gas in one side of the chamber while compressing gas from the evaporator on the other side of the piston. The check valves are arranged so that the compressed gas is forced from the cylinder 24 into the conduit 40. It is made double acting and operates on both strokes. By way of example, the gas entering the compressor of the present invention is typically in the gaseous phase at about 70° F. having a pressure of about 30 psi. The vapor pressure is about 70 psi for the common refrigerant used in most automobiles.
The pump 58 at this time will be observed to be injecting liquid or near liquid phase refrigerant. At the point where the liquid is introduced, it is believed that the gas is normally in a vapor phase and is super heated. The liquid phase refrigerant which is compressed by the pump 58 and introduced in small quantities into the conduit 40 tends to convert the gas flowing in the conduit 40 through the heat exchanger to a saturated vapor. This tends to increase the density of the gas past the point of introduction. This results in a temperature drop and a pressure increase or volume increase. As will be observed, an increase in volume is prevented by the unyielding construction so that the pressure increases markedly. The pumped liquid volume is about 1/1600 of the pumped gas volume.
In the routine opreation of an automobile, the engine cooling system operates at temperatures typically controlled by a thermostat. In the winter time, the temperatures may sag significantly, but the air conditioning equipment of the present invention is normally not operated in the winter time. In the summer time, temperatures in the range of 180° to about 230° are readily achieved. The heat exchanger thus raises the temperature of the saturated gas in vapor phase to about 180°. At about 180° R-12 Freon refrigerant has a saturated vapor pressure of about 550 psi. Thus, the conduit 40 upon emerging from the heat exchanger delivers refrigerant in the vapor phase to the fluid motor 50 at about 550 psi and at about 180° F. The gas which is introduced into the fluid motor 50 surrenders energy and thus drops in pressure. It drops from about 550 psi to about 200 or 300 psi. There may or may not be a drop in temperature. The exhaust gas from the fluid motor 50 is then transferred to the condenser by the conduit 16 which extends from the present invention to the cooperating equipment. At this juncture, the gas is still typically a saturated vapor phase fluid. At the condenser, the high pressure vapor phase fluid is cooled from the vapor phase to liquid and a commensurate drop in pressure is experienced. The refrigerant then goes from the condenser to the evaporator where the pressure is lowered again at the expansion valve to enable the refrigerant to change phases from liquid to vapor thereby absorbing heat and the cycle is repeated.
If different refrigerants are used, the exemplary pressures and temperatures noted above may be altered, however, the operation will be similar.
The apparatus of the present invention has several significant advantages not the least of which is that it does not take any power from the crank shaft of the engine. This freedom of a rotative power source thus enables the compressor of the present invention to be mounted under the hood in the traditional manner or it can be located elsewhere at a more convenient location. The device tends to be more efficient and operate better when the water supplied from the engine cooling system is hotter. Thus, as the cooling water becomes hotter, more energy is imparted to the refrigerant in the heat exchanger causing the pump to operate with greater power. Since it removes heat energy from the cooling water, it actually tends to prevent the overheating of the engine cooling system. A significant factor is that the unit is entirely sealed and has no protruding or external shafts which require seals, magnetic clutches and the like. In addition, it has a minimum of moving parts and the parts which do move are totally and fully located within the apparatus and their mechanical life should be great by virtue of this protection.
As a matter of convenience, the heat exchanger 42 may be a separate entity remote from the radiator for cooling the engine or the heat exchanger 42 may be incorporated on the inside of the cooling system such as the point of introduction of the hot water into the radiator. A common housing encloses both pumps and has no projecting shafts.
The foregoing is directed to the preferred embodiment of the present invention but the scope thereof is determined by the claims which are as follows.