WO2003071202A1

WO2003071202A1 - Liquid/vapour separator in an air-conditioning circuit

Info

Publication number: WO2003071202A1
Application number: PCT/FR2003/000417
Authority: WO
Inventors: Guy Montaille
Original assignee: Valeo Climatisation
Priority date: 2002-02-18
Filing date: 2003-02-10
Publication date: 2003-08-28
Also published as: FR2836211A1; FR2836211B1; AU2003247359A1

Abstract

The invention relates to a liquid/vapour separator in an air-conditioning circuit. According to the invention, the circuit comprises a phase separator, between the evaporator and the compressor, in which the fluid circulates in an essentially horizontal longitudinal direction and comes into contact with disrupting elements (15). Said disrupting elements are designed to intercept any liquid droplets that may be contained in the fluid such that said droplets are collected on a drainage wall (11) and only the fluid in the gaseous state is conveyed to the compressor. The invention is suitable for use in the air conditioning of vehicle passenger compartments.

Description

Liquid / vapor separator in an air conditioning loop

The invention relates to a coolant loop, in particular for an air conditioning installation for the passenger compartment of a vehicle, comprising a compressor capable of raising the pressure of the fluid to the gaseous state, a condenser capable of condensing the fluid compressed by the compressor, a means of expansion capable of lowering the pressure of the condensed fluid, and an evaporator capable of passing the expanded fluid from the liquid state to the gaseous state before its return to the compressor, as well as a phase separator for avoid the entry of fluid in the liquid state into the compressor.

Such loops are known in which the phase separator is a complex, costly and bulky component, at the same time ensuring the functions of reservoir to absorb variations in the volume of fluid in the loop, and of filter.

The object of the invention is to achieve phase separation by simple and economical means, and taking up little space, lack of space being a frequent constraint in automobile construction.

The invention relates in particular to a loop of the kind defined in the introduction, and provides that in the phase separator, placed in the evaporator or after it, the fluid circulates in a substantially horizontal longitudinal direction and meets with disturbing elements capable of intercepting the liquid droplets possibly contained in the fluid so as to gather them on a collecting wall, only the fluid in the gaseous state being returned to the compressor.

Optional, complementary or alternative characteristics of the invention are set out below: - Said collector wall is a substantially cylindrical wall with a substantially horizontal axis defining the interior volume of the phase separator.

- The disturbing elements are formed or attached projecting from said substantially cylindrical wall.

- The disturbing elements include a deflecting wall physically separated from the collecting wall and suitable for projecting said droplets against the latter.

- The phase separator comprises a bent tube having a first branch oriented in said longitudinal direction and at least a second branch oriented transversely to said longitudinal direction, the fluid flowing in the bent tube from the first branch to the second branch and said deflecting wall being formed by the wall of the bent tube at the junction of said branches.

- The outlet of the second branch is located in the immediate vicinity of the collecting wall.

- The exit of the second branch is flared.

- The bent tube has at least two second branches, the second branches being arranged divergently around the axis of the first branch.

- Said deflecting wall is formed by a helically twisted strip.

- Said deflecting wall is formed by at least one fin extending radially from an axial core substantially over the entire perimeter thereof.

- The deflecting wall comprises at least one fin wound in a helix. - The deflecting wall comprises a multiplicity of fins arranged along a helix.

- The deflecting wall comprises a multiplicity of fins arranged in staggered rows.

- The strip twisted in a helix or the fins are perforated.

- The edges of the helically twisted strip or fins have cutouts.

- Said cylindrical wall has a circular section of diameter equal to or greater than the width of the strip or the outside diameter of the fins.

- Means are provided for collecting oil collecting in the phase separator and returning it to the compressor.

- The phase separator is a component interposed between the outlet of the evaporator and the inlet of the compressor.

- The phase separator is housed in an outlet space of the evaporator.

- The loop includes a reservoir capable of absorbing variations in the volume of the fluid.

- The tank is integrated into the condenser, the latter comprising a sub-cooling zone downstream of the tank.

- The regulator is in the form of a calibrated orifice.

The invention also relates to an independent phase separator, and an evaporator comprising a phase separator housed in an outlet space, usable in a loop as defined above. The characteristics and advantages of the invention will be explained in more detail in the description below, with reference to the accompanying drawings.

Figure 1 is a diagram of a coolant loop according to the invention for a vehicle air conditioning installation.

FIG. 2 is a schematic view in longitudinal section of a phase separator usable in the circuit of FIG. 1.

Figure 3 is a sectional view along line III-III of Figure 2.

Figures 4 and 5. are views similar to Figure 3, relating to variants.

Figures 6 and 7 are views similar to Figures 2 and 3 respectively, relating to another variant.

Figures 8, 10, 12, 14, 15, 17, 18 and 20 are partial views in longitudinal section of separators. of phases according to the invention.

Figures 9, 11 and 13 are end views of inserts belonging to the phase separators of Figures 8, 10 and 12 respectively.

Figures 16 and 19 are cross-sectional views of the phase separators of Figures 14 and 18 respectively.

Figure 21 is a schematic longitudinal sectional view of an evaporator according to the invention.

The loop shown schematically in Figure 1, designated by the reference 1, conventionally comprises a compressor 2, a condenser 3, a regulator 4 and an evaporator 5. The evaporator 5 is intended to extract heat of an air flow to transfer it to the fluid circulating in the loop, and the condenser 3 is intended to extract this heat, as well as that produced by the compression of the fluid in the compressor 2, to transfer it to the external atmosphere to the vehicle.

The loop 1 also includes a phase separator 6 according to the invention, disposed between the outlet of the evaporator 5 and the inlet of the compressor 2.

In the example shown in Figures 2 and 3, the phase separator comprises a cylindrical housing of revolution 10, oriented horizontally, bounded by a cylindrical side wall 11 and two end walls 12 and 13. The end wall 12 is crossed in a sealed manner by a branch 14, extending horizontally along the axis of the housing 10, of a T-shaped tube, which is completed by a transverse branch 15 open at its two ends which are very close to the wall 11. The end of the branch 14 opposite the branch 15 is connected to the outlet of the evaporator 5, while an outlet pipe 16 starting from the wall 13 is connected to the inlet of the compressor 2.

During the operation of the loop, the fluid coming from the evaporator circulates in the branch 14 in the direction of the branch 15. When it reaches the downstream end of the branch 14, it strikes the wall of the branch 15 oriented transversely. The liquid droplets which it can contain are then projected against the wall 11 by the open ends of the branch 15. At least part of the droplets is vaporized following the impacts against the wall of the branch 15 and against the wall 11 The possible residue collects along the lower generatrix of the wall 11 to be vaporized later, while the fluid in the gaseous state leaves the housing 10 through the pipe 16 to be conveyed to the inlet of the compressor 2. also seen in Figure 2 a thin oil return pipe 17 which passes inside the pipe 16 and opens into the housing 10 just above the lower generator of the wall 11. This tubing is used to collect the particles of lubricating oil mixed with the coolant in the compressor, which are separated from the gaseous fluid at the same time as the droplets of liquid coolant, so as to bring this oil to the compressor. Such an oil return pipe, although not shown, is advantageously also provided in the examples of FIGS. 8 to 21.

In the variant of FIG. 4, the fluid circulation tube comprises, instead of a single diametrical branch (or of two opposite radial branches) 15, three radial branches 20 arranged in a star, at a mutual angular spacing of 120 ° . Similarly, in the variant of Figure 5, the tube has four radial branches (or two diametrical branches) 21 arranged in a cross, that is to say mutually perpendicular. Of course, these examples are not limiting as to the number and the arrangement of the transverse branches of the tube. In particular, it is possible to provide a single radial branch connected to the longitudinal branch by an elbow. Or the transverse branches are not necessarily oriented perpendicular to the axis of the housing and can be inclined.

The example illustrated in FIGS. 6 and 7 differs from that of FIGS. 2 and 3 in that the open ends of the transverse branch 22 are flared. Of course, this feature can be adopted regardless of the number and arrangement of the transverse branches.

The phase separators shown in Figures 8 to 13 also have a cylindrical housing having a side wall 25 and two end walls not shown, which are respectively provided with an inlet opening and an outlet opening for the fluid. A cylindrical core of revolution 26 is disposed inside the housing, coaxial therewith, and defines with the wall 25 an annular space 27 for the circulation of the fluid. The core 26 can be a hollow sheet metal body provided with at least one transverse partition preventing the fluid from circulating inside the core. In the example of FIGS. 8 and 9, a fin 28 integral with the core extends radially from the latter up to contact with the wall 25 or in the immediate vicinity thereof. As can be seen in FIG. 8, the shape of the fin 28 is that generated by a straight line segment oriented radially whose origin moves along a propeller 29 traced on the core. Figure 9 shows perforations 30 formed in the fin 28 and distributed around the axis of the core.

The fin 28 forms an obstacle to the longitudinal circulation of the fluid, and projects any droplets against the wall 25. The perforations 30 amplify the turbulent nature of the circulation of the fluid.

In the example of FIGS. 10 and 11, the helical fin 28 is replaced by a multiplicity of fins 35 extending radially from locations located on the core 26 along a propeller 36. The fins 35 are substantially contiguous along the propeller and can even partially overlap.

In the example of FIGS. 12 and 13, fins 40 extend radially from the core 26 and are contained in several planes perpendicular to the axis of the core. Several fins 40 are arranged in the same plane, and the fins contained in consecutive planes are angularly offset, forming a staggered arrangement. In the example illustrated, each plane contains four fins arranged in a cross, and the fins of two neighboring planes are mutually offset by 30 °, so that the fins present in. together twelve different orientations around the axis and as a whole occupy the majority of the cross section of the annular volume 27.

Figures 14 to 20 illustrate examples in which all or almost all of the interior volume of the phase separator is open to the circulation of the fluid. In the example of FIGS. 14 and 16, the housing, of which only the cylindrical wall 40 is partially represented, exclusively contains a strip 41 whose width corresponds to the internal diameter of the wall 40. This strip is twisted in a helix, this is that is to say that its shape is that generated by a diameter of the wall 40, each end of which moves along a helix traced on the wall. Perforations 42 are arranged through the strip 41, half-width thereof, and distributed over its length.

The strip 41 and the perforations 42 play the same role as the fins and the perforations of the examples in FIGS. 8 to 13.

In the variant of FIG. 15, the perforations 42 are replaced by notches 43 formed on the edges of the strip and distributed along the latter.

FIG. 17 illustrates another variant in which the diametrical strip is replaced by a strip 50 whose width is substantially less than the inside diameter of the cylindrical wall 51 of the housing. The median axis of the strip 50 is arranged in a helix. This strip can be fixed in places to the wall 51, for example by welds.

In variants not illustrated, perforations such as 30 or 42 or notches such as 43 may be provided in the fins of Figures 10 to 13 or in the strip of Figure 17. Similarly, the perforations 30 of Figure 9 may be deleted or replaced with notches.

In the examples of FIGS. 18 to 20, the phase separator housing contains no insert, only irregularities in its wall acting to intercept the droplets. In FIGS. 18 and 19, these irregularities are constituted by helical ribs 60 formed on the cylindrical wall 61. In FIG. 20, these are discrete projections 70 formed on the cylindrical wall 71, extending each on a fraction of the perimeter thereof and with a mutual angular offset, and- oriented obliquely with respect to the longitudinal axis.

Finally, Figure 21 illustrates an evaporator according to the invention.

This evaporator 80 essentially consists of a stack of corrugated plates and spacers as described for example in FR 2 747 462 A, to which reference may be made for more details on the structure of this stack. The plates are mutually aligned in a longitudinal direction (from left to right of the figure), and have two manifolds 81, 82 mutually juxtaposed in a lateral direction (from top to bottom), each formed by alignment, in the direction longitudinal, inlet or outlet chambers 83 belonging respectively to the different plates 84. The manifolds are subdivided as a whole into connecting pipes, the connecting pipes which belong to the same manifold succeeding one another in the longitudinal direction and do not not communicating directly with each other, while in each connecting pipe the inlet or outlet chambers communicate with each other by openings 85 formed in the walls of the plates, the plates defining a path for the first fluid between an upstream connecting pipe 86 and a downstream link pipe 87, passing alternately from a link pipe one belonging to one of the manifolds to a connecting pipe belonging to the other manifold, via U-shaped paths each of which connects the inlet and outlet chambers of the same plate. The upstream connection pipe, via a longitudinal tube 88, and the downstream connection pipe are connected to inlet and outlet passages 89, 90 provided at the same end 91 of the stack.

According to the invention, a disturbing element such as those described above is housed in the connecting pipe downstream 87, in this case a strip 92 twisted in a helix as described with reference to FIGS. 14 to 16.

Of course, a phase separator according to the invention can be incorporated into an evaporator of a different type from that illustrated. Likewise, the other described forms of phase separators can be incorporated into an evaporator.

Since the phase separator according to the invention does not play the role of a fluid reservoir, it is advantageous to use a condenser comprising such an integrated reservoir and a sub-cooling zone.

Furthermore, the invention advantageously applies to a coolant loop in which the expansion of the fluid is ensured by a calibrated orifice or by a thermostatic expansion valve.

Claims

claims

1. Cooling fluid loop (1), in particular for an air conditioning installation in the passenger compartment of a vehicle, comprising a compressor (2) capable of raising the pressure of the fluid in the gaseous state, a clean condenser (3) condensing the fluid compressed by the compressor, an expansion means (4) capable of lowering the pressure of the condensed fluid, and an evaporator (5) capable of passing the expanded fluid from the liquid state to the gaseous state before it return to the compressor (2), as well as a phase separator (6) to prevent the entry of fluid in the liquid state into the compressor, characterized in that in the phase separator, placed in the evaporator or after the latter, the fluid circulates in a substantially horizontal longitudinal direction and meets disturbing elements (15) capable of intercepting the liquid droplets possibly contained in the fluid so as to collect them on a collecting wall (11), only the e fluid in the gaseous state being returned to the compressor.

2. Buckle according to claim 1, in which said collecting wall is a substantially cylindrical wall (11) of substantially horizontal axis delimiting the interior volume of the phase separator.

3. Buckle according to claim 2, in which the disturbing elements (60) are formed or attached projecting from said substantially cylindrical wall (61).

4. Buckle according to one of claims 1 and 2, wherein the disturbing elements comprise a deflecting wall (15) physically separated from the collecting wall (11) and suitable for projecting said droplets against the latter.

5. Buckle according to claim 4, wherein the phase separator comprises a bent tube (14, 15) having a first branch (14) oriented in said direction longitudinal and at least one second branch (15) oriented transversely to said longitudinal direction, the fluid flowing in the bent tube from the first branch to the second branch and said deflecting wall being formed by the wall of the bent tube at the junction of said branches.

6. Buckle according to claim 5, wherein the outlet of the second branch is located in the immediate vicinity of the collecting wall.

7. Buckle according to one of claims 5 and 6, wherein the outlet of the second branch (22) is flared.

8. Buckle according to one of claims 5 to 7, in which the bent tube has at least two second branches (20), the second branches being arranged divergently around the axis of the first branch.

9. Buckle according to claim 4, in which said deflecting wall is formed by a strip (41) twisted in a helix.

10. The loop of claim 4, wherein said deflecting wall is formed by at least one fin (28) extending radially from an axial core (26) substantially over the entire perimeter thereof.

11. Buckle according to claim 10, in which the deflecting wall comprises at least one fin (28) wound in a helix.

12. Buckle according to claim 10, in which the deflecting wall comprises a multiplicity of fins (35) arranged along a helix (36).

13. The loop of claim 10, wherein the deflecting wall comprises a plurality of fins (40) arranged in staggered rows.

14. Buckle according to one of claims 9 to 13, wherein the helically twisted strip (41) or the fins (28) are perforated (30, 42).

15. Buckle according to one of claims 9 to 14, wherein the edges of the helically twisted strip or fins have cutouts (43).

16. Buckle according to one of claims 9 to 15, wherein said cylindrical wall (25, 40) has a circular section of diameter equal to or greater than the width of the strip or the outside diameter of the fins.

17. Buckle according to one of the preceding claims, in which means (17) are provided for collecting oil collecting in the phase separator and returning it to the compressor,

18. Loop according to one of the preceding claims, in which the phase separator is a component (6) interposed between the outlet of the evaporator (5) and the inlet of the compressor (2).

19. Loop according to one of claims 1 to 17, wherein the phase separator is housed in an outlet space (87) of one evaporator (80).

20. Buckle according to one of the preceding claims, comprising a reservoir capable of absorbing variations in the volume of the fluid.

21. A loop according to claim 20, in which the reservoir is integrated into the condenser (3), the latter comprising a sub-cooling zone downstream of the reservoir.

22. Buckle according to one of the preceding claims, in which the regulator is in the form of a calibrated orifice.

23. A phase separator usable in a loop according to claim 18, in which the fluid circulates in a substantially horizontal longitudinal direction and meets disturbing elements (15) capable of intercepting the liquid droplets possibly contained in the fluid so as to collect them on a collecting wall (11), only the fluid in the gaseous state being conveyed at the outlet of the phase separator.

24. An evaporator (80) usable in a loop according to claim 19, comprising a phase separator housed in an outlet space (87), in which the fluid circulates in a substantially horizontal longitudinal direction and meets its own disturbing elements (92) intercepting the liquid droplets possibly contained in the fluid so as to gather them on a collecting wall, only the fluid "in the gaseous state being conveyed at the outlet of one evaporator.