cascading vortex tube arrangement

Abstract

The invention relates to an arrangement of at least two cascaded vortex tubes (12), in which each vortex tube (12) comprises a generator (14) coaxial to a main axis A, a main tube (16) and a conical valve (20) located at a free axial end (22) of the main tube (16), in which a primary vortex flow (28) flows axially with respect to the main axis A in a peripheral part of the main tube (16) and in which a secondary vortex flow (30) flows axially with respect to the main axis A in a radially central part of the main tube (16),characterized in that the vortex tubes (12) are connected to directly mix the primary vortex flow (28) of one vortex tube (12) with the primary vortex flow (28) of the other vortex tube (12), or to directly mix the secondary vortex flow (30) of one vortex tube (12) with the secondary vortex flow (30) of the other vortex tube (12). Figure for abbreviation: Fig. 3,

Description

Title of the invention: Cascaded vortex tube arrangement Technical field

[0001] The invention relates to an arrangement for producing air flows at different temperatures from a single air flow, by using several vortex tubes also known as Ranque-Hilsch tubes. STATE OF THE PRIOR ART

[0002] Vortex tubes allow an incoming flow at a fixed pressure to be separated into two lower pressure flows, one hotter and the other colder than the initial flow. This phenomenon is called the temperature separation effect.

[0003] These tubes are used in various applications such as the cooling of parts or cutting tools in workshops, cooling of electrical cabinets, dehumidification of gas samples or chemical separation in gas flows.

[0004] A vortex tube consists of a tube, a generator comprising a set of nozzles tangential to the tube, a conical valve at the hot outlet, and a cold outlet. This control valve makes it possible to modify the proportion of the inlet flow exiting on the hot side and cold side.

[0005] The performance of vortex tubes is generally given as a function of the CMF (Cold Mass Fraction), which is the ratio of the mass flow rate leaving the cold side compared to the mass flow rate entering.

[0006] It has been proposed to arrange vortex tubes in series or in parallel to improve the performance and / or effects of the installation, whether in the production of cold air or the production of hot air.

[0007] The aim of the invention is to propose an innovative arrangement of vortex tubes (resulting from a mix between series and parallel configurations) making it possible to further improve the efficiency of the coupling of the vortex tubes. Statement of the invention

[0008] The invention proposes an arrangement of at least two vortex tubes in cascade, in which each vortex tube comprises a generator coaxial with a main axis A, a main tube and a conical valve located at a free axial end of the main tube,

[0009] wherein a primary vortex flow flows axially relative to the main axis A in a peripheral portion of the main tube and wherein a secondary vortex flow flows axially relative to the main axis A in a radially central portion of the main tube,

[0010] characterized in that the vortex tubes are placed in communication to directly mix the primary vortex flow of one vortex tube with the primary vortex flow of the other vortex tube or to directly mix the secondary vortex flow of one vortex tube with the secondary vortex flow of the other vortex tube.

[0011] According to such an arrangement, the vortex tubes are directly coupled to each other. There is therefore a minimization of pressure losses which could harm its efficiency.

[0012] Preferably, at least one vortex tube comprises a secondary tube through which the secondary flow of said at least one vortex tube is discharged from said at least one vortex tube, and the secondary tube of one vortex tube opens into the main tube of the other vortex tube, to directly mix the secondary swirl flow of said at least one vortex tube with the secondary swirl flow of the other vortex tube.

[0013] Preferably, said secondary tube of said at least one vortex tube opens into the main tube of the other vortex tube near the generator of said other vortex tube.

[0014] Preferably, the free end of the main tube of a vortex tube opens into the main tube of the other vortex tube via the generator of said other vortex tube to directly mix the primary vortex flow of said one vortex tube with the primary vortex flow of said other vortex tube.

[0015] Preferably, said other vortex tube is a parallel flow vortex tube.

[0016] Preferably, the conical valve of a vortex tube is annular and the conical valve of another vortex tube is radially full.

[0017] Preferably, the annular conical valve is crossed by the secondary tube of said at least one vortex tube which opens into the main tube of the other vortex tube.

[0018] Preferably, the solid conical valve opens into the generator of the other vortex tube.

[0019] Preferably, the arrangement comprises means for positioning the vortex tubes coaxially with the main axis A.

[0020] Preferably, the annular conical valve participates in the positioning of the vortex tubes coaxially with the main axis A. Brief description of the drawings

[0021] Other characteristics and advantages of the invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended figures among which:

[0022] [Fig. 1] is a schematic perspective representation of a unitary vortex tube according to prior know-how, which is of the cross-flow type;

[0023] [Fig.2] is an axial section of a unitary vortex tube according to prior art, which is of the parallel flow type;

[0024] [Fig.3] is an axial sectional view of an arrangement according to a first embodiment of the invention;

[0025] [Fig.4] is a schematic perspective representation of an arrangement such as re presented in [Fig.3];

[0026] [Fig.5] is a larger scale detail showing an example of a connection between a main tube and a secondary tube of the vortex tubes assembled according to the first embodiment;

[0027] [Fig.6] is a view similar to that of [Fig.3], showing an arrangement according to another embodiment of the invention.

[0028] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0029] [Fig.l] shows a first type of elementary vortex tube 12, commonly referred to as "cross-flow".

[0030] This vortex tube 12 comprises a generator 14 having a main axis A, a main tube 16 and a secondary tube 18 coaxial with the main axis A which are arranged axially on either side of the generator 14. The vortex tube 12 further comprises a conical valve 20 located at a free axial end 22 of the main tube 16.

[0031] The diameter of the secondary tube 18 is less than the diameter of the main tube 16.

[0032] The generator 14 comprises a plurality of injection nozzles 24 which are oriented tangentially relative to the main axis A and through which air feeds the vortex tube 12 via the generator 14.

[0033] The compressed air enters the generator 14 tangentially to the main axis A, producing a primary swirl flow 28 (visible in Figures 2 and 3). This primary swirl flow 28 flows axially along the main tube 16, which is the tube of largest diameter, from its end 26 by which the main tube 16 is connected to the generator 14 towards the free axial end 22 of the main tube 16 which carries the conical valve 20.

[0034] Upon encountering the conical valve 20, the primary swirl flow 28 divides into a hot air flow which exits the main tube 16 at the conical valve 20 and a cold secondary swirl flow 30 which flows in the opposite direction to the primary swirl flow 28, i.e. from the free end 22 of the main tube 16 to a free end 21 of the secondary tube 18 and radially inside the latter.

[0035] The secondary vortex flow 30 passes axially through the generator 14 and is then evacuated through the secondary tube 18.

[0036] [Fig.2] shows a second type of elementary vortex tube 12 which is of the type commonly referred to as "parallel flows".

[0037] This vortex tube 12 comprises a generator 14, a main tube 16 and a valve conical 20 located at a free axial end 22 of the main tube 16, which is opposite the generator 14.

[0038] According to this second type of vortex tube 12, the compressed air enters the generator 14 tangentially to the main axis A, producing a hot primary vortex flow 28 flowing axially relative to the main axis A in a peripheral portion of the main tube 16 and a cold secondary flow 30 flowing axially relative to the main axis A in a radially central portion of the main tube 16.

[0039] According to this second type of vortex tube 12, the two swirling flows 28, 30 are coaxial with each other and with the main axis A and pass through the main tube 16 in the same direction, that is to say from the generator 14 towards the conical valve 20, at which they are discharged separately.

[0040] For this purpose, the conical valve 20 is annular, as will be described later.

[0041] Figures 3 and 4 show an arrangement of two vortex tubes 12 ele cascading comments according to a first embodiment of the invention.

[0042] It will be understood that the invention is not limited to an arrangement comprising only two elementary vortex tubes 12 and that the arrangement may comprise a greater number of elementary vortex tubes 12 arranged in cascade.

[0043] The two vortex tubes 12 are vortex tubes of the first type, with cross flow. They are coaxial with the same common main axis A and are axially offset from each other.

[0044] The connection of the vortex tubes 12 is carried out by connecting the main tube 16 of a first vortex tube with the secondary tube 18 of the second vortex tube 12.

[0045] Furthermore, this connection consists in that the secondary tube 18 of the second vortex tube 12 extends at least partly inside the main tube 16 of the first vortex tube 12.

[0046] Thanks to this arrangement, the secondary vortex flow 30 which comes from the second vortex tube 12 mixes directly with the secondary vortex flow produced in the first vortex tube 12.

[0047] The connection of the vortex tubes 12 is therefore direct, there is no component generating a pressure drop between them, which increases the overall efficiency of the arrangement.

[0048] According to a preferred embodiment, the secondary tube 18 of the second vortex tube 12 has a free end through which it opens axially, which is located in the main tube 16 of the first vortex tube 12 near the generator 14.

[0049] As can be seen in more detail in [Fig.5], the conical valve 20 associated with the main tube 16 of the first vortex tube 12, which is the one crossed by the secondary tube 18 of the second vortex tube 12, is of annular shape to be able to evacuate the flow of hot air in particular.

[0050] The conical valve 20 delimits a cylindrical housing coaxial with the main axis A which is preferably complementary to the secondary tube 18 of the second vortex tube 12. The conical valve 20 makes it possible, thanks to this, to participate in a positioning of the second vortex tube 12 coaxially with the first vortex tube 12 and with the main axis A.

[0051] The conical valve 20 associated with the main tube 16 of the second vortex tube 12 is solid, that is to say that it extends radially up to the main axis A since it does not need to be physically crossed by another component.

[0052] According to a preferred embodiment, each vortex tube 12 is produced as an independent component, i.e. the generator 14, the main tube 16, the secondary tube 18 and the conical valve 20 are fixed to each other in a known manner, for example by welding, brazing or by three-dimensional printing.

[0053] The vortex tubes 12 are then assembled together to obtain a desired configuration, with two or more vortex tubes 12.

[0054] Such a solution is particularly advantageous because only two references of vortex tubes 12 are necessary, namely a vortex tube 12 corresponding to the first vortex tube 12 of the assembly which has just been described, and comprising an annular valve 20 as shown in [Fig. 5] and which is intended to be crossed by the secondary tube 18 of another vortex tube 12, and a vortex tube 12 corresponding to the second vortex tube 12 of the assembly which has just been described comprising a solid valve 20, as defined previously.

[0055] As previously indicated, the vortex tubes 12 are arranged coaxially with each other and with the main axis A and they are offset from each other along the main axis A.

[0056] The arrangement comprises means for holding the vortex tubes 12 coaxially with the main axis A.

[0057] According to a first embodiment, these holding means comprise the central housing of the conical valve 20 associated with the main tube 16 of the first vortex tube 12. This conical valve 20 being annular, the housing which it delimits is complementary to the secondary tube 18 of the second vortex tube 12.

[0058] [Fig.6] shows another embodiment of the invention comprising two vortex tubes 12 associated in series, each of which is of one of the two types.

[0059] According to this other embodiment, it is the main tubes 16 of the two vortex tubes 12 which are placed in communication with each other. The primary vortex flow 28 of one vortex tube mixes with the primary flow 28 of the other vortex tube 12, while the secondary vortex flow 30 of each of the two vortex tubes 12 opens out at one of the axial ends of the assembly corresponding to the associated vortex tube 12.

[0060] According to this embodiment, the conical valve 20 of a first vortex tube 12, which is the cross-flow one (the one on the left in [Fig.6]) opens into the generator of the second vortex tube 12 which is the parallel-flow one (the one on the right in [Fig.6]). The hot air flow from the first vortex tube 12 then mixes with the primary swirling flow 28 of the second vortex tube 12.

[0061] The resulting hot air exits through the conical valve 20 of the second vortex tube 12.

[0062] Here, in the first vortex tube 12, the secondary vortex flow 30 circulates counter-current to the primary vortex flow 28 and in the second vortex tube 12, the secondary vortex flow 30 circulates in the same direction as the primary vortex flow 28.

[0063] Thus, each secondary vortex flow 30 is discharged towards an axial end of the arrangement.

[0064] For this, the conical valve 20 of the first vortex tube 12 is solid, that is to say it extends radially up to the main axis A and the conical valve 20 of the second vortex tube 12 is annular, so that the secondary swirl flow 30 can be evacuated at the free axial end 22 of the main tube 16.

[0065] Whatever the embodiment, the main tube 16 of a first vortex tube 12 is placed in communication with the main tube 16 of a second vortex tube or the secondary tube 18 of a first vortex tube 12 is placed in communication with the secondary tube 18 of a second vortex tube 12.

[0066] This communication is carried out at the free end 22 of the main tube 16 of a vortex tube 12, or at the free end 21 of the secondary tube 18 of a vortex tube 12, which allows for a direct connection and therefore optimization of the production of heat or cold.

Claims

Claims

1. Arrangement of at least two vortex tubes (12) in cascade, wherein each vortex tube (12) comprises a generator (14) coaxial with a main axis A, a main tube (16) and a conical valve (20) located at a free axial end (22) of the main tube (16), wherein a primary vortex flow (28) flows axially with respect to the main axis A in a peripheral portion of the main tube (16) and wherein a secondary vortex flow (30) flows axially with respect to the main axis A in a radially central portion of the main tube (16),characterized in that the vortex tubes (12) are connected to directly mix the primary vortex flow (28) of one vortex tube (12) with the primary vortex flow (28) of the other vortex tube (12) or to directly mix the secondary vortex flow (30) of one vortex tube (12) with the secondary vortex flow (30) of the other vortex tube (12).,

2. Arrangement according to claim 1, characterized in that at least one vortex tube (12) comprises a secondary tube (18) through which the secondary flow (30) of said at least one vortex tube (12) is discharged from said at least one vortex tube (12), and in that the secondary tube (18) of one vortex tube (12) opens into the main tube (16) of the other vortex tube (12), to directly mix the secondary vortex flow (30) of said at least one vortex tube (12) with the secondary vortex flow (30) of the other vortex tube (12).

3. Arrangement according to claim 2, characterized in that said secondary tube (18) of said at least one vortex tube (12) opens into the main tube (16) of the other vortex tube (12) near the generator (14) of said other vortex tube (12).

4. Arrangement according to claim 1, characterized in that the free end of the main tube (16) of one vortex tube (12) opens into the main tube (16) of the other vortex tube (12) via the generator (14) of said other vortex tube (12) to directly mix the primary vortex flow (28) of said one vortex tube (12) with the primary vortex flow (28) of said other vortex tube (12).

5. Arrangement according to claim 4, characterized in that said other vortex tube (12) is a parallel flow vortex tube.

6. Arrangement according to any one of the preceding claims, characterized in that the conical valve (20) of one vortex tube (12) is annular and the conical valve (20) of another vortex tube (12) is radially solid.

7. Arrangement according to claim 6, in combination with claim 2 or 3, characterized in that the annular conical valve (20) is crossed by the secondary tube (18) of said at least one vortex tube (12) which opens into the main tube (16) of the other vortex tube (12)

8. Arrangement according to claim 6, in combination with claim 4, characterized in that the solid conical valve (20) opens into the generator (14) of the other vortex tube (12).

9. Arrangement according to any one of the preceding claims, characterized in that it comprises means for positioning the vortex tubes coaxially with the main axis A.

10. Arrangement according to claim 9, in combination with claim 7, characterized in that the annular conical valve (20) participates in the positioning of the vortex tubes coaxially with the main axis A.

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