Field of Invention

The present invention relates generally to heat exchangers, and

particularly to a refrigerant distributor tube for heat exchangers.

Background

Heat exchangers may be used, for example, in air conditioning and

refrigeration systems to heat/cool a fluid. The heat exchanger, which may be an evaporator, includes a header that receives fluid, such as refrigerant, from a refrigerant source. The fluid flows through the header and is delivered to coils of the heat exchanger where heat transfer occurs.

Summary of Invention

The present invention provides a distributor tube having a tubular body, a plurality of circumferentially spaced apart channels and at least one opening through an exterior wall of the tubular body, wherein either the plurality of channels extend helically along a length of the distributor tube or the at least one opening extends helically along the length of the distributor tube. In this way, a homogenous mixture of a two-phase liquid refrigerant may be distributed to specific locations within a header from a first end of the tubular body to a second end.

According to one aspect of the invention, a distributor tube is provided including a tubular body having first and second ends, a plurality of circumferentially spaced apart channels extending longitudinally along an interior of the tubular body, and at least one opening through an exterior wall of the tubular body for allowing fluid to pass from a respective channel to an outside of the tubular body, wherein either the plurality of channels extend helically along a length of the distributor tube or the at least one opening extends helically along the length of the distributor tube.

A fluted insert may be disposed within the interior of the tubular body, the fluted insert including a plurality of radially outwardly opening fins that are circumferentially arranged along a longitudinal axis of the distributor tube.

Ends of the fins may cooperate with an interior wall of the tubular body to form the plurality of channels.

The at least one opening may extend helically along the length of the distributor tube. The plurality of channels may be straight channels extending along the length of the distributor tube.

The at least one opening may include an opening for each respective channel, each opening following a spiraled path along the longitudinal axis of the distributor tube.

The plurality of channels may extend helically along the length of the distributor tube.

The plurality of channels may have a different cross-sectional area.

The channels may have progressively larger cross-sectional areas, and wherein the channels of progressively larger cross-sectional area communicate with the at least one opening progressively further from the first end of the tubular body.

The channels may have progressively larger lengths such that the channel with the largest cross-sectional area has the largest length.

According to another aspect of the invention, a distributor tube is provided including a tubular body having first and second ends, a plurality of circumferentially spaced apart channels extending longitudinally along an interior of the tubular body, the channels having progressively larger cross-sectional areas, and at least one opening through an exterior wall of the tubular body for allowing fluid to pass from the plurality of channels to an outside of the tubular body, wherein the channels of progressively larger cross-sectional area communicate with the at least one opening progressively further from the first end of the tubular body.

According to still another aspect of the invention, a method of distributing a fluid is provided including receiving the fluid in a plurality of channels of a tubular body, at least one channel having a cross-sectional area that is smaller than a cross-sectional area of the other channels, and delivering the fluid from the channels to respective channel outlets such that the fluid received in the channel having the smaller cross- sectional area travels a shorter distance in the tubular body than the fluid received in a channel having a larger cross-sectional area.

Either the plurality of channels may extend helically along a length of the tubular body or the channel outlets extend helically along the length of the tubular body.

Both the plurality of channels and the channel outlets may extend helically along a length of the tubular body. According to a further aspect of the invention, a distribution device is provided that includes a plurality of tubes having first and second ends, the plurality of tubes having progressively larger cross-sectional areas and an opening through a wall of the tube for allowing fluid to pass from the tubes to a heat exchanger header, wherein the openings are spaced along a length of the distribution device such that fluid received in one of the plurality of tubes with a smallest cross-sectional area travels a shorter distance through the respective tube than fluid received in one of the plurality of tubes having a larger cross-sectional area.

The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a perspective view of an exemplary heat exchanger;

Fig. 2 is a partial cross-sectional view of an exemplary expansion device including a distributor tube according to the invention;

Fig. 3 is a perspective view of an exemplary tubular body of the distributor tube;

Fig. 4 is an exploded view of the exemplary expansion valve, distributor tube and header housing;

Fig. 5 is a perspective view of another exemplary distributor tube according to the invention;

Fig. 6 is an end view of the distributor tube of Fig. 5;

Fig. 7 is a perspective view of an exemplary insert of the distributor tube of Fig.

5;

Fig. 8 is a perspective view of an exemplary tubular body of the distributor tube of Fig. 5;

Fig. 9 is a partial cross-sectional view of another exemplary heat exchanger; Fig. 10 is a perspective view of yet another exemplary distributor tube according to the invention;

Fig. 1 1 is a perspective view of an exemplary insert of the distributor tube of Fig. 10;

Fig. 12 is a perspective view of an exemplary tubular body of the distributor tube of Fig. 10;

Fig. 13 is a perspective view of another exemplary expansion device including a distributor tube according to the invention; Fig. 14 is a perspective view of still another exemplary expansion device including a distributor tube according to the invention;

Fig. 15 is a partial perspective view of another exemplary distributor tube according to the invention;

Fig. 16 a partial perspective view of still another exemplary distributor tube according to the invention;

Fig. 17 is a partial cross-sectional view of still another exemplary heat exchanger having the distributor tube of Fig. 16;

Fig. 18 a partial perspective view of yet another exemplary distributor tube according to the invention;

Fig. 19 is a partial cross-sectional view of yet another exemplary heat exchanger having the distributor tube of Fig. 18;

Fig. 20 a partial perspective view of a further exemplary distributor tube according to the invention; and

Fig. 21 is a partial cross-sectional view of a further exemplary heat exchanger having the distributor tube of Fig. 20.

Fig. 22 is side view of another exemplary heat exchanger.

Fig. 23 is a partial cross-sectional view of the heat exchanger of Fig. 22.

Fig. 24 is a side view of still another exemplary heat exchanger.

Fig. 25 is a side view of yet another exemplary heat exchanger

Detailed Description

The principles of the present application have particular application to distributors for heat exchangers and thus will be described below chiefly in this context. It will of course be appreciated, and also understood, that the principles of the invention may be useful in fluid transfer applications where it is desirable to maintain high fluid velocity across the length of a tube.

Turning now to Fig. 1 , a heat exchanger is illustrated generally at reference numeral 10. The heat exchanger, which may be any suitable heat exchanger, may be used as an evaporator for cooling and as a condenser for heating. During cooling fluid in the system is in a two-phase state and during heating the fluid is in a liquid state. The heat exchanger 10 may include a header 12 or be coupled to the header 12 in any suitable manner. The header 12 includes a housing 14 that houses an expansion device 16, which includes an expansion valve 18 and a distributor tube 20 that may remain embedded and fully functional in both heating and cooling modes. The expansion valve 18 may be any suitable expansion valve, such as an electrical expansion valve as described in U.S. Patent Application Nos. 12/817,972 and

13/509,359 which are hereby incorporated herein by reference.

As shown in Fig. 2, the expansion valve 18 includes a body 22 housing a guide bushing 24 for axially guiding a piston 25 in the body 22. Formed inside the body is a chamber, which includes a distribution portion 26, a throttling portion 28, and an inlet portion 30. The inlet portion 30 is configured to supply high pressure liquid refrigerant, which may be a refrigerant/lubricant mixture, to the throttling portion 28 for expansion in the throttling portion, and the distribution portion delivers high velocity two-phase refrigerant to an outlet 32 of the expansion valve 18. The throttling portion 28 is formed in a check valve body 34 that is movable in the body 20. The check valve body is normally biased by a spring (not shown) to a closed position whereat the check valve body seals against a valve seat.

The expansion valve 18 also includes an adjustment device 36 that includes the piston 25 having at one end a valve pin that is progressively tapered. The piston 25 is movable by a drive mechanism 38 (e.g. an actuator) into and relative to the throttling portion 28 to provide a variable size throttling orifice through which the refrigerant is throttled for simultaneous expansion, mixing and distribution.

Additionally, the piston is movable to a closed position to prevent fluid flow to the throttling portion.

The drive mechanism 38 includes an electric motor 40, a gear cup 42, a gear train 44, a bearing 46, the guide busing 24 (which may be also referred to as a plunger guide), and a screw 48 rotated by the motor. A nut 50 is provided meshed to the screw and axially translated by the screw upon rotation of the screw. An anti- rotation feature is provided to prevent the translating nut from rotating with the screw. The anti-rotation feature may be of any suitable type, such as providing the exterior of the nut and interior bore of the guide bushing 24 with corresponding non-circular cross-sections.

Fluid entering the expansion valve, such as high pressure liquid refrigerant, enters the expansion valve 18 via an inlet 60 and exits the expansion valve via the outlet 32 as a high velocity two-phase refrigerant. This two-phase refrigerant flows from the outlet 32 to the distributor tube 20, and then exits the distributor tube at a plurality of points along a length of the distributor tube. The fluid exiting the distributor tube at the plurality of points then flows to a plurality of plates 68 in the heat exchanger.

Referring now to Figs. 2-4, the distributor tube 20 will be discussed in detail. The distributor tube 20 includes a tubular body 70 having first and second ends 72 and 74, the second end being closed by a plug 76, and a plurality of circumferentially spaced apart channels 78 extending longitudinally along an interior of the tubular body 70. The plurality of circumferentially spaced apart channels 78 are illustrated as straight channels, although it will be appreciated that the channels may be helical as discussed below. The channels 78 may have the same cross-sectional area or may have different cross-sectional areas, such as progressively larger areas.

To form the channels 78, the distributor tube 20 includes a fluted insert 80 disposed within the interior of the tubular body 70. The fluted insert 80 includes a hub 82 and a plurality of radially outwardly opening fins 84 extending from the hub that are circumferentially arranged along a longitudinal axis A of the distributor tube 20. The fins have respective ends 86 that cooperate with the interior wall of the tubular body 70 to form the plurality of channels 78. The fins 84 may be evenly spaced around the hub 82 to form channels having the same cross-sectional area or spaced

progressively farther apart to form channels having different cross-sectional areas. The fluted insert 80 may be coupled to the tubular body 70 in any suitable manner or may be press fit to the tubular body. Alternatively, the tubular body and insert may be formed as a single piece.

To allow fluid to pass from a respective channel 78 to an outside of the tubular body 70, the tubular body includes at least one opening 90 through an exterior wall of the tubular body, and in the illustrated embodiment an opening 90 for each channel 78. As shown in Fig. 3, the openings 90 extend helically along the length of the distributor tube such that the openings follow a spiraled path along the longitudinal axis A of the distributor tube. In this way, fluid may be distributed to specific locations within the header 12 from the first end 72 of the tubular body 70 to the second end 74 while maintaining high velocity flow. If the channels 78 have different cross-sectional areas, the fraction of total mass flow distributed to the specific locations may be controlled. The openings 90 may have the same area or may have different areas, such as progressively larger areas.

During operation, fluid, such as liquid refrigerant, enters the expansion valve 18 at the inlet 60 and flows through a throttling orifice 28, where the now two-phase refrigerant is homogenously mixed and exits as a high velocity two-phase fluid. The homogenous mixture then flows to the outlet 32, where it flows to the plurality of channels 78, thereby splitting the two-phase refrigerant when it is homogeneous. The fluid then flows through the channels 78 and exits the channels via the respective openings 90, thereby delivering the fluid to specified locations in the header 12 while maintaining a high velocity flow across the length of the header.

Turning now to Figs. 5-8, an exemplary embodiment of the distributor tube is shown at 120. The distributor tube 120 is substantially the same as the above- referenced distributor tube 20, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the distributor tube 20 is equally applicable to the distributor tube 120 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

Referring now to Figs. 5 and 6, the distributor tube 120 includes a tubular body 170 having first and second ends 172 and 174 and a plurality of circumferentially spaced apart channels 178a-178n extending longitudinally along an interior of the tubular body 170. The plurality of circumferentially spaced apart channels 1 78a-178n are straight channels having different cross-sectional areas, which are shown as progressively larger areas. As shown, the channel 178a has the smallest cross- sectional area and the channel 178n has the largest cross-sectional area, although it will be appreciated that the channels may have the same cross-sectional area. The channels 178-178n may have the same length along a longitudinal axis A of the tube 120 or the channels may have progressively larger lengths such that the channel 178n with the largest cross-sectional area has the largest length.

To form the channels 178a-178n, the distributor tube 120 includes a fluted insert 180 disposed within the interior of the tubular body 170. The fluted insert 180 includes a hub 182 and a plurality of radially outwardly opening fins 184 extending from the hub that are circumferentially arranged along the longitudinal axis A of the distributor tube 120. The fins 184 are circumferentially arranged progressively further apart to form the channels 178a-178n of progressively larger cross-sectional area. The fins have respective ends 186 that cooperate with the interior wall of the tubular body 170 to form the plurality of channels 178a-178n. To allow fluid to pass from a respective channel 178a-178n to an outside of the tubular body 170, the tubular body includes at least one opening 190, such as a slot through an exterior wall of the tubular body, and in the illustrated embodiment an opening 190a-190n for each channel 178a-178n. The openings 190a-190n extend helically along the length of the distributor tube such that the openings follow a spiraled path along the longitudinal axis A of the distributor tube. The channels 178a- 178n of progressively larger cross-sectional area communicate with the openings 190a-190n progressively further from the first end 172 of the tubular body 170.

Alternatively, the at least one opening may be a single slot as shown in Fig. 8 extending helically along the length of the distributor tube and the fins cooperate with the interior wall of the tubular body and the single opening to form respective output openings for respective channels.

During operation, fluid, such as liquid refrigerant, enters the expansion valve 18 at the inlet 60 and flows through a throttling orifice 28, where the now two-phase refrigerant is homogenously mixed and exits as a high velocity two-phase fluid. The homogenous mixture then flows to the outlet 32, where it flows to the plurality of channels 178a-178n, thereby splitting the two-phase refrigerant when it is

homogeneous. The fluid then flows through the channels 178a-178n to the respective openings 190a-190n such that the fluid received in the channel 178a having the smaller cross-sectional area travels a shorter distance in the tubular body 170 than the fluid received in a channel 178n having a larger cross-sectional area. The fluid exiting the openings 190a-190n is delivered to specified locations in the header 12 while maintaining a high velocity flow across the length of the header.

Turning now to Figs. 9-12, an exemplary embodiment of the heat exchanger is shown at 210 and the distributor tube is shown at 220. The distributor tube 220 is substantially the same as the above-referenced distributor tube 20, and consequently the same reference numerals but indexed by 200 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the distributor tubes 20 and 120 is equally applicable to the distributor tube 220 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

The distributor tube 220 includes a tubular body 270 having first and second ends 272 and 274 and a plurality of circumferentially spaced apart channels 278a- 278n extending longitudinally along an interior of the tubular body 270 and helically along the length of the distributor tube 220. The plurality of circumferentially spaced apart helical channels 278a-278n have different cross-sectional areas, which are shown as progressively larger areas. As shown, the channel 278a has the smallest cross-sectional area and the channel 278n has the largest cross-sectional area. The channels 278a-278n may have the same length along a longitudinal axis A of the tube 220 or the channels may have progressively larger lengths such that the channel 278n with the largest cross-sectional area has the largest length.

To form the channels 278a-278n, the distributor tube 220 includes a fluted insert 280 disposed within the interior of the tubular body 270. The fluted insert 280 includes a hub 282 and a plurality of radially outwardly opening fins 284 extending from the hub that are circumferentially arranged along the longitudinal axis A of the distributor tube 220. The fins 284 are circumferentially arranged progressively further apart to form the channels of progressively larger cross-sectional area. The fins have respective ends 286 that cooperate with the interior wall of the tubular body 270 to form the plurality of channels 278a-278n.

To allow fluid to pass from a respective channel 278a-278n to an outside of the tubular body 270, the tubular body 270 includes at least one opening 290, such as a slot through an exterior wall of the tubular body, and in the illustrated embodiment a single straight opening 290 extending longitudinally along the length of the distributor tube. Ends of the fins 284 cooperate with the interior wall of the tubular body 270 and the single opening 290 to form respective output openings 292a-292n for respective channels 278a-278n. The channels 278a-278n of progressively larger cross-sectional area communicate with the respective output openings 292a-292n progressively further from the first end 272 of the tubular body 270.

During operation high pressure liquid refrigerant enters the expansion valve 218 at the inlet 260 and flows through a throttling orifice, where the now two-phase refrigerant is homogenously mixed and exits as a high velocity low pressure liquid vapor. The homogenous mixture then flows to the outlet 232, where it flows to the plurality of channels 278a-278n, thereby splitting the two-phase refrigerant when it is homogeneous. The fluid then flows through the channels 278a-278n to the respective output opening 292a-292n such that the fluid received in the channel 278a having the smaller cross-sectional area travels a shorter distance in the tubular body 270 than the fluid received in a channel 278n having a larger cross-sectional area. The fluid exiting the output openings is delivered to specified locations in the header 212 while maintaining a high velocity flow across the length of the header. The opening 290 may be provided at a portion of the tubular body 270 facing the plates 268 to provide the refrigerant more directly to the plates.

Turning now to Fig. 13, an exemplary embodiment of the expansion device is shown at 316. The expansion device 316 is substantially the same as the above- referenced expansion device 16, and consequently the same reference numerals but indexed by 300 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the expansion device 16 is equally applicable to the expansion device 316 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

Referring to Fig. 13, the expansion device 316 includes an expansion valve 318 and a plurality of distributor tubes 320a-320n. The tubes are helically wound around one another and have first ends 372a-372n, respectively, coupled to the expansion valve 318 and second ends and 374a-374n, respectively, which may be capped. Each tube 320a-320n includes a respective opening 390a-390n through a wall of the tube for allowing fluid to pass from the tube to a heat exchanger header. The openings 390a-390n are substantially linearly arranged along a length of the distributor device to provide the refrigerant more directly to the plates and evenly along the length of the distributor device.

The plurality of tubes may have the same cross-sectional area or progressively larger cross-sectional areas. In tubes that have progressively larger cross-sectional areas, the openings may be spaced along a length of the distribution device such that fluid received in the tube with a smallest cross-sectional area travels a shorter distance through the respective tube than fluid received the tube having a larger cross-sectional area.

Turning now to Fig. 14, an exemplary embodiment of the expansion device is shown at 416. The expansion device 416 is substantially the same as the above- referenced expansion device 316, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the expansion device 316 is equally applicable to the expansion device 416 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

Referring to Fig. 14, the expansion device 416 includes an expansion valve 418 and a plurality of distributor tubes 420a-420n circumferentially spaced around an axis of the distributor device. The tubes have first ends 472a-472n, respectively, coupled to the expansion valve 418 and second ends and 474a-474n, respectively, which may be capped. Each tube 420a-420n includes a respective opening 490-490n through a wall of the tube for allowing fluid to pass from the tube to a heat exchanger header. The openings 490a-490n are arranged along a length of the distributor device to provide the refrigerant evenly along the length of the distributor device.

The plurality of tubes may have the same cross-sectional area or progressively larger cross-sectional areas. In tubes that have progressively larger cross-sectional areas, the openings are spaced along a length of the distribution device such that fluid received in the tube with a smallest cross-sectional area travels a shorter distance through the respective tube than fluid received tube having a larger cross-sectional area.

Turning now to Fig. 15, an exemplary embodiment of the distributor tube is shown at 520. The distributor tube 520 is substantially the same as the above- referenced distributor tube 20, and consequently the same reference numerals but indexed by 500 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the distributor tube 20 is equally applicable to the distributor tube 520 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

The distributor tube 520 is a one-piece tube having a tubular body 570 and an insert 580 integrally formed, for example by extrusion. The distributor tube 520 includes a plurality of circumferentially spaced apart channels 578 extending longitudinally along the length of the tube. The channels 578 are straight channels having the same cross-sectional area. The distributor tube 520 also includes a plurality of openings 590 extending helically along the length of the distributor tube. In the illustrated embodiment the openings 590 are equally spaced along the length of the tube, and the openings are indexed to the channels 578 to attain a consistent volume flow rate through each opening 590.

Turning now to Figs. 16-19, exemplary embodiments of the distributor tube are shown at 620 and 720. The distributor tubes 620 and 720 are substantially the same as the above-referenced distributor tube 520, and consequently the same reference numerals but indexed by 100 and 200 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the distributor tube 520 is equally applicable to the distributor tubes 620 and 720 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

As shown in Figs. 16 and 17, the distributor tube 620 is a one-piece tube having a tubular body 670 and an insert 680 integrally formed. The distributor tube 620 includes a plurality of circumferentially spaced apart channels 678 extending longitudinally along the length of the distributor tube and a plurality of openings 690 extending helically along the length of the distributor tube. The distributor tube has a nose cone inlet 694 for uniformly delivering fluid to the plurality of channels 678.

As shown in Figs. 18 and 19, the distributor tube 720 is a one-piece tube having a tubular body 770 and an insert 780 integrally formed. The distributor tube 720 includes a plurality of circumferentially spaced apart channels 778 extending longitudinally along the length of the distributor tube and a plurality of openings 790 extending helically along the length of the distributor tube. The distributor tube has a concave inlet 794 for creating turbulence and for mixing two-phase refrigerant flowing into the tube 720 to increase the velocity of the fluid.

Turning now to Figs. 20 and 21 , an exemplary embodiment of the distributor tube is shown at 820. The distributor tube 820 is substantially the same as the above- referenced distributor tube 520, and consequently the same reference numerals but indexed by 300 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the distributor tube 520 is equally applicable to the distributor tube 820 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable. The distributor tube 820 may be a one-piece tube having a tubular body 870 and insert 880 integrally formed, for example by extrusion, or formed as a multi-piece tube. The distributor tube 820 includes an inlet portion 894 that may have any suitable shape, such as a flat inlet, a nose cone inlet, a concave inlet, etc. Attached to an outer surface of the tubular body 870 of the distributor tube 820 or integrally formed therewith is a continuous baffle 896 that extends along the length of the tube. In the illustrated embodiment, the continuous baffle 896 is a helically wound baffle that is formed by extrusion. The baffle 896 serves as a plurality of fins that cooperate with an inner wall of the header to segment the header to direct the fluid exiting the openings 890 to respective plates 868 in the heat exchanger and to aid in refrigerant retention.

Turning now to Figs. 22 and 23, an exemplary embodiment of the heat exchanger is shown at 910. The heat exchanger 910 is substantially the same as the above- referenced heat exchanger 10, and consequently the same reference numerals but indexed by 900 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the heat exchanger 10 is equally applicable to the heat exchanger 910 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

The heat exchanger 910 may include a header 912 or be coupled to the header

912 in any suitable manner. The header 912 includes a housing 914 that houses a distributor tube 920, which may be any of the above-described distributor tubes. The header 912 may be coupled to a fixed orifice device 918, also referred to as a fixed orifice metering device, spaced from the header 912 via a fluid conduit 917, and the fixed orifice device 918 may be coupled to a source of fluid via a fluid conduit 919. Fluid entering the fixed orifice device 918, such as high pressure liquid refrigerant, enters the fixed orifice device 918 via the fluid conduit 919 and exits the fixed orifice device 918 as a two-phase refrigerant. The two-phase refrigerant flows from the fixed orifice device 918 through the fluid conduit 917 to the distributor tube 920, and then exits the distributor tube at a plurality of points along a length of the distributor tube. The fluid exiting the distributor tube at the plurality of points then flows to a plurality of plates 968 in the heat exchanger. In an embodiment shown in Fig. 23, an optional nozzle 921 may be provided inside the header 912 to increase the velocity and turbulence of the two-phase refrigerant flowing to the distributor tube 920. Turning now to Fig. 24, an exemplary embodiment of the heat exchanger is shown at 1010. The heat exchanger 1010 is substantially the same as the above- referenced heat exchanger 10, and consequently the same reference numerals but indexed by 1000 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the heat exchanger 10 is equally applicable to the heat exchanger 1010 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable.

The heat exchanger 1010 may include a header 1012 or be coupled to the header 1012 in any suitable manner. The header 1012 includes a housing 1014 that houses a distributor tube (not shown), which may be any of the above-described distributor tubes. The header 1012 may be coupled to an expansion valve 1018, such as a thermostatic expansion valve that is spaced from the header 1012 via a fluid conduit 1017, and the thermostatic expansion valve 1018 may be coupled to a source of fluid via a fluid conduit 1019. Fluid entering the thermostatic expansion valve 1018, such as high pressure liquid refrigerant, enters the thermostatic expansion valve 1018 via the fluid conduit 1019 and exits the thermostatic expansion valve 1018 as a two- phase refrigerant. The two-phase refrigerant flows from the thermostatic expansion valve 1018 through the fluid conduit 1017 to the distributor tube, and then exits the distributor tube at a plurality of points along a length of the distributor tube. The fluid exiting the distributor tube at the plurality of points then flows to a plurality of plates 1068 in the heat exchanger. Similar to the heat exchanger 910, an optional nozzle may be provided inside the header 1012 to increase the velocity and turbulence of the two-phase refrigerant flowing to the distributor tube.

Turning now to Fig. 25, an exemplary embodiment of the heat exchanger is shown at 1 1 10. The heat exchanger 1 1 10 is substantially the same as the above- referenced heat exchanger 10, and consequently the same reference numerals but indexed by 1 100 are used to denote structures corresponding to similar structures in the distributor tube. In addition, the foregoing description of the heat exchanger 10 is equally applicable to the heat exchanger 1 1 10 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the distributor tubes may be substituted for one another or used in conjunction with one another where applicable. The heat exchanger 1 1 10 may include a header 1 1 12 or be coupled to the header 1 1 12 in any suitable manner. The header 1 1 12 includes a housing 1 1 14 that houses a distributor tube (not shown), which may be any of the above-described distributor tubes. The header 1 1 12 may be coupled to an expansion valve 1 1 18, such as an electrical expansion valve as described above, that is spaced from the header 1 1 12 via a fluid conduit 1 1 17, and the expansion valve 1 1 18 may be coupled to a source of fluid via a fluid conduit 1 1 19. Fluid entering the expansion valve 1 1 18, such as high pressure liquid refrigerant, enters the expansion valve 1 1 18 via the fluid conduit 1 1 19 and exits the expansion valve 1 1 18 as a two-phase refrigerant. The two-phase refrigerant flows from the expansion valve 1 1 18 through the fluid conduit 1 1 17 to the distributor tube, and then exits the distributor tube at a plurality of points along a length of the distributor tube. The fluid exiting the distributor tube at the plurality of points then flows to a plurality of plates 1 168 in the heat exchanger.

Similar to the heat exchanger 910, an optional nozzle may be provided inside the header 1 1 12 to increase the velocity and turbulence of the two-phase refrigerant flowing to the distributor tube.

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and

modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.