FR2785552A1 - FILTRATION DEVICE FOR REFRIGERATION CIRCUIT AND FILTRATION METHOD USING SUCH A DEVICE - Google Patents

Abstract

The present invention relates to a filtration device for a refrigerant circuit comprising a hollow body (2) and a molecular sieve, the hollow body defining a space (2 ') and being provided on one side with a bottom and having l 'other side an opening closed by a shutter (6). The closure part has an orifice (11) for entering the fluid and is integral with, or adjoins, the molecular sieve which is separated from the space delimited by the hollow body by a grid (20) for passing the fluid, the inlet orifice (11) being extended by a mechanical filter (23) elongated around an axis, inserted into the molecular sieve and arranged to diffuse the fluid radially inside the sieve.

Description

FILTRATION DEVICE FOR REFRIGERATION CIRCUIT AND

  FILTRATION PROCESS USING SUCH A DEVICE

  The present invention relates to filtration devices for a refrigerant circuit of the type comprising a hollow body provided on one side with a bottom and having on the other side an opening closed by a sealing piece, said sealing piece

  having a fluid inlet port.

  It also relates to a filtration process

  using such a device.

  It finds a particularly important although not exclusive application in the field of desiccant bottles for circuit

  motor vehicle air conditioning.

  Filtration devices for refrigeration circuits of the type defined above are already known. Such devices contain a filter element capable of retaining impurities and the water contained

in the refrigerant.

  The filter element is of annular shape, crossed by a plunger tube of reduced diameter in communication with the outlet orifice

downstream of the filter group.

  Such an arrangement has drawbacks.

  In particular, it requires the manufacture of a specific porous tank of annular shape.

containing the filter material.

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  This reservoir must also be introduced into the hollow body, around the diameter tubing.

  reduced, which poses manufacturing problems.

  The known devices are moreover generally constituted by steel or aluminum parts, welded together according to the TIG technique, which risks damaging the material of the temperature-sensitive filter element, during

the making.

  io The present invention aims to provide a device that better meets those previously known to the requirements of practice, in particular in that it allows a manufacture not likely to damage the filter material, simple to implement, using fewer parts than in the prior art, and using materials such as

  aluminum alloys, significantly lighter.

  To this end, the invention proposes in particular a filtration device for a refrigerant circuit comprising a hollow body and a molecular sieve, the hollow body delimiting a space and being provided on one side with a bottom and having on the other side an opening closed by a sealing piece, said sealing piece comprising a fluid inlet orifice, characterized in that the sealing piece is integral with, or adjoins, the molecular sieve which is separated from said space by a fluid passage grid, and in that the inlet orifice is extended by an elongated mechanical filter

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  about an axis, inserted into the molecular sieve and arranged to diffuse the fluid radially to

inside said sieve.

  In advantageous embodiments, recourse is had to one and / or the other of the following arrangements: - the closure part comprises an outlet for the fluid, connected to the space delimited by the body hollow by a dip tube passing through the filter screen; - The dip tube, for evacuating the fluid, has its open end directly near the bottom of the hollow body; - The fluid outlet orifice is located in the bottom of the hollow body, the mechanical filter being for example centered with respect to the closure part; - The molecular sieve has a cross section equal to or substantially equal to that of the hollow body and extends over a determined height; - The determined height of the molecular sieve is between half and nine tenths of the height of the space delimited by the hollow body, for example two thirds or three quarters; - the mechanical filter is cylindrical; - the mechanical filter is conical, the end of the cone being located towards the passage grid; - a felt sheet is interposed between the molecular sieve and the fluid passage grid;

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  - The device comprises means for fixing the inlet and outlet connection tubes of the fluid by snap-fastening; - The hollow body is a first half-shell provided with a cylindrical wall and the closure part is a second half-shell formed in one piece by a bottom and a cylindrical wall introduced frictionally into the first half-shell to which it is fixed by gluing, the first half-shell being crimped on the periphery of the bottom of the second half-shell; - the molecular sieve is contained by the second half-shell; - the hollow body and the closure piece are made of aluminum alloy; - the tubing is made of plastic; - the molecular sieve belongs to a removable filter cartridge, separable from the sealing part. The invention also provides a method of

  filtration with a device as described below

  above and in particular a method of filtering a refrigerant fluid by a device comprising a hollow body delimiting a space, characterized in that the fluid is filtered directly at the inlet of the device by a mechanical filter, the fluid is radially diffused directly at the outlet of the mechanical filter inside a sieve

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  molecular, and then evacuates said fluid at

  across said space of the hollow body.

  Advantageously, the fluid is evacuated from the space by means of a tube plunging to the bottom of the hollow body. The invention will be better understood on reading the

  description which follows of several modes of

  particular achievements given as examples

not limiting.

  The description refers to the drawings which

  accompany it in which: - Figure 1 is a side view in axial section, of a first embodiment of a

device according to the invention.

  FIG. 2 is a perspective view,

  cut away from the device of Figure 1.

  - Figure 3 is a partial perspective view of another embodiment of the part

shutter in Figure 1.

  - Figure 4 is a side sectional view of a second embodiment of the device according to the invention. - Figure 5 is a side view, in section, of a third embodiment of a device according to

the invention.

  - Figure 6 is a side sectional view of a fourth embodiment of a device according to the invention.

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  FIG. 7 is a perspective view,

  cut away, of the device of figure 6.

  In the following description, we will use the

  same reference numbers to designate identical items. Figures 1 and 2 show a device 1 according to

  a first embodiment of the invention.

  The device 1 comprises a hollow body 2 made of aluminum alloy or steel, formed by a cylindrical wall 3 for example 1 to 3 mm thick, provided on one side with a bottom 4 formed by a single piece with the wall 3 for example by impact spinning, and having a central cavity in the form of a cup 4 ′. The hollow body delimits a space 2 ′ for the passage of the fluid and has on the other side an opening 5 closed by a closure piece 6, also made of aluminum alloy, of substantially cylindrical shape at the level of the closure and comprising an upper connection portion 7 with inlet (E) and outlet (S) pipes for the fluid

refrigerant (see figure 2).

  The liquid is for example a refrigerant

  of the type known under the references HFA134A or CFC12.

  The part 6 comprises a fluid outlet orifice 8, arranged to be connected at 9, by means of a tube 10 having an enlargement (see FIG. 2), in a sealed manner and

  known in itself, with an outlet pipe (S).

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  The part 6 also comprises an orifice 11 for entering the liquid into the hollow body, arranged to be connected at 12, in an identical manner to the pipe

outlet, to the inlet pipe (E).

  The outlet orifice 8 is moreover connected, on the side of the hollow body, to a plunging tube 13

  up to the cup 4 'from the bottom 4 of the hollow body.

  The end 14 of the tubing, opposite the part 6, is therefore directly connected to the space 15 located at

  near the bottom 4 of the hollow body.

  The tubing is for example made of plastic, for example polyamide known under the name 6-6, loaded to the order of 30% by weight of glass fibers. It is also advantageously made of aluminum. It has a part 16 which makes the connection with the orifice 8, and a main portion 17, having a bend and a constant cylindrical cross section

to its end 14.

  The dimension of the external diameter of this tubing is for example between about a fifth and about a tenth of the diameter

internal of the hollow body.

  In the embodiment more particularly described here, the closure part 6 is in the form of a cylindrical half-shell and comprises a cylindrical filter screen 18 with an external diameter identical to the

internal diameter of the half-shell.

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  More precisely, the filtering screen is formed of a molecular sieve, for example constituted by a layer of aluminosilicate beads, held in sandwich between the bottom 19 of the closure piece and a lower grid 20, constituted by a plate with holes or a lattice structure, made of material

identical to the tubing.

  The grid 20 is for example provided with ribs 21 for radial stiffening. It abuts down against a cylindrical shoulder 22 formed by bending the lower edge of the cylindrical wall of the half-shell, said cylindrical wall being integral with the bottom of the closure wall. The tubing 13 is fixed to the inlet of the orifice 8, on the bottom wall of the closure piece 6, for example by bonding with an adhesive of the type known under the name "Loctite" or equivalent, and / or by deformation of part 6 for example

according to three points.

  The inlet 11 is in communication with the molecular sieve via a filter

mechanical or conical volume 23.

  More precisely, this mechanical filter 23 consists of a cone, the base of which has a diameter substantially equal to that of the inlet orifice provided with longitudinal slots 24, for example 0.5 mm

of thickness, of passage of the fluid.

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  The slots are distributed regularly around the periphery of the cone, and symmetrically, for example four slots extending substantially over the height

  of the cone arranged alternately with four half

  slits, extending from the base of the cone, towards the top, so that the reentering fluid is then diffused laterally and radially outward from the filter in the molecular sieve,

substantially homogeneously.

  The closure piece 6 comprises on its periphery, a peripheral annular projection 27 which abuts against the upper edge of the opening of the hollow body during the crimping of the

  shutter piece, as we will see.

  In one embodiment, an O-ring seal 28 can be provided, for example of elastomeric material of the type known under the

denomination VITON.

  This seal is threaded onto the end of the closure piece located on the side of the hollow body by

compared to the projection 27.

  The closure piece 6 is also fixed to the end of the hollow body by one or more beads of adhesive, for example of the type known under the name KOMMERLING, under the reference CORAPOX 562L2, or by means of a thin film. of said glue distributed over the internal face of the periphery of the end of the hollow body or of the

  external face of the piece opposite.

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  The end of the hollow body is then crimped onto the periphery of said part inserted into the opening, the lateral projection 24 coming in

stop on the hollow body.

  In Figures 1 and 2 there is shown a method of fixing the inlet (E) and outlet (S) pipes by fixing flange 29 provided with holes 30 for fixing by screws cooperating in the holes 31 opposite -vis of

the sealing piece 6.

  We will now describe how the

  device described with reference to Figures 1 and 2.

  Filtration / desiccant of the refrigerant

is carried out as follows.

  The fluid enters the device through the orifice 11 of the closure piece 6 and immediately and directly enters the mechanical filter

conical 23.

  It then diffuses radially through the filter in a substantially homogeneous manner, however favoring the upper part of the cone, in the space

cylindrical filter screen.

  It thus passes inside the sieve where it separates from its traces of moisture and solid particles, then leaves the sieve via the grid 20, before entering the space 2 ′ of the hollow body 2 then emerging via the tubing 13 through the outlet orifice 8. Advantageously, an indicator of the humidity level of the refrigerant fluid (not l 2785552 shown) can be provided, at the outlet, making it possible to assess the saturation of the molecular sieve, and / or an indicator of filling.

  This indicator is arranged in a manner known per se.

  even to hold on to the operating pressure of the

device (of the order of 27 bars).

  In Figure 4 we have shown another

device 33 according to the invention.

  The sealing piece 34 is here constituted by a cylindrical half-shell 35 formed by a thin wall open on the side of the filter screen 36 which it includes, and closed on the other side by a bottom 37 provided with two sockets 38 integral with the bottom 37, of

  passage of the end of the pipes (E) and (S).

  A flange 39 fixed to the bottom of the half-shell by gluing and a counter flange 40 ensure the fixing

  pipes on the bottle irremovable.

  In this embodiment, the mechanical filter 41 is constituted by a screened cylinder of diameter substantially equal to that of the passage bush 38, entirely immersed in the molecular sieve 36,

  the section of the grids not exceeding 1 mm2.

  Figure 5 shows another device 42 or

bottle according to the invention.

  The device 42 has a shutter piece 43 whose orifices 44 and 45 for the inlet and outlet of the refrigerant are arranged to allow connections to the hollow body by snap-fastening.

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  A piece 46, cylindrical, secured to the bottom 37 for example by gluing, allows the introduction and blocking by quick connection of the ends of the pipes E and S. The type of connection described in the document

  FR-A-2 686 961 is for example usable.

  Figures 6 and 7 show another mode of

  production of a device 50 according to the invention.

  The device 50 comprises a hollow body 51 in the form of a cylindrical half-shell 52 provided with a bottom 53. The bottom 53 is formed by a thick plate provided with a device 54 known in itself allowing filling and checking pressure, and the outlet orifice 55 for example bent to allow a lateral exit of the outlet pipe S. The orifice 55 is a communication with the space 56 delimited by the internal face of the bottom 53, the internal face of the cylindrical half-shell 52 and the grid 57 for passage of the fluid in the form of a circular pellet of small thickness, comprising for example a circular tower turbine arranged regularly. The closure piece 58 is in turn constituted by a cylindrical half-shell 59 provided

  a bottom 60 in the form of a cylindrical plate.

  The fluid inlet orifice 61 is centered relative to the bottom and is extended by a mechanical filter

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  23 of the type described with reference to FIGS. 1 and 2,

  fully immersed in the molecular sieve 18.

  This is inserted on the one hand between the bottom and the cylindrical wall of the half-shell 59, and on the other hand between a sheet of felt 62 commuted in it-

  same and the grid 57 for passage of the fluid.

  In this embodiment, the space 56 delimited by the hollow body is reduced, and for example by volume between the fifth and the tenth of the

volume of molecular sieve.

  The advantages of the invention compared with the prior art are in particular: - a weight saving of around 30 to 50% compared to steel parts; - easy assembly, without soldering or welding, and therefore without risk of leakage or damage to the filter materials; - reduced pressure losses due to a larger passage section over a larger part

of the journey.

  As is obvious and as it follows from the above, the present invention is not limited to the embodiments more particularly described. On the contrary, it embraces all the variants and in particular those where the inlet orifice is on the side of the body, or on the bottom of the body, those where the material used for the body, as for the internal tubing, is a material plastic such as glass fiber reinforced polyamide; the

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  crimping is carried out by filtering or by magneto-

forming.

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Claims (14)

  1. A filtration device (1, 33, 42, 50) for a refrigerant circuit comprising a hollow body (2, 51) and a molecular sieve (18, 36), the hollow body delimiting a space (2 ', 56) and being provided on one side with a bottom (4, 53) and having on the other side an opening (5) closed by a closure piece (6, 43, 58), said closure piece comprising a fluid inlet orifice (11, 61), characterized in that the closure part is integral with, or adjoins, the molecular sieve which is separated from the space delimited by the hollow body by a grid (20, 57 ) for the passage of the fluid, and in that the inlet orifice (11, 61) is extended by a mechanical filter (23, 41) elongated around an axis, inserted into the molecular sieve and arranged to diffuse the fluid radially inside said screen. 2. Device according to claim 1, characterized in that the closure part (6) comprises an orifice (3) for the outlet of the fluid, connected to the space delimited by the hollow body by a tube (13)   plunger passing through the filter screen.   3. Device according to claim 2, characterized in that the dip tube (13) has its open end directly near the bottom (4, 4 ') of the hollow body. 16 2785552   4. Device according to claim 1, characterized in that the orifice (55) outlet of the   fluid is located in the bottom (53) of the hollow body.   5. Device according to any one of   previous claims, characterized in that the   molecular sieve (18, 36) has a cross section equal to or substantially equal to that of   hollow body and extends over a determined height.   6. Device according to claim 5, characterized in that the determined height of the molecular sieve is between half and nine tenths of the height of the space delimited by the hollow body.   7. Device according to any one of   previous claims, characterized in that the   mechanical filter (41) is cylindrical.   8. Device according to any one of   Claims 1 to 6, characterized in that the filter   mechanical (23) is conical, the end of the cone being   located towards the gate (20, 57).   9. Device according to any one of   previous claims, characterized in that   felt sheet (62) is interposed between the screen   (18) molecular and the passage grid (57).   10. Device according to any one of   previous claims, characterized in that the   closure piece comprises means (46) for fixing the inlet connection tubes and fluid outlet by snap-fastening. 17 2785552   11. Device according to any one of   previous claims, characterized in that the   hollow body (51) is a first half-shell provided with a cylindrical wall and the closure part (6, 43, 58) is a second half-shell formed in one piece by a bottom and a cylindrical wall introduced friction in the first half-shell to which it is fixed by gluing, the first half-shell being crimped on the periphery of the bottom of the second io half-hull.   12. Device according to claim 11, characterized in that the molecular sieve is contained by the second half-shell of the closure part. 13. Device according to any one of   Claims 1 to 11, characterized in that the sieve   molecular is constituted by a filter cartridge   demountable separable from the sealing piece.   14. A method of filtering a refrigerant fluid by a device comprising a hollow body delimiting a space, characterized in that the fluid is filtered directly at the inlet of the device by a mechanical filter, the fluid is radially diffused directly to the outlet of the mechanical filter inside a molecular sieve, and said fluid is then discharged through said space (2 ′, 56) of the hollow body.