Patent Application
20250189184
The invention concerns a fluid circulation device as well as an installation and a method using such a device.
More particularly, the invention concerns a fluid circulation device, in particular for a refrigerator or cryogenic liquefier, comprising a casing which is sealed against the exterior of the device, and contains an electrical machine such as an electric motor or an alternator, the device comprising a cycle gas circuit which subjects the cycle gas to a thermodynamic change between a minimal pressure and a maximal pressure when the device is operating, the device comprising at least one unit to drive the cycle gas in the circuit, such as a compressor wheel, said drive unit being coupled in rotation to the electrical machine, the device comprising an electrical junction box which is sealed against the exterior of the device, and in which there passes electrical circuitry having a first end connected to the electrical machine, and a second end connected to at least one electrical connector which opens onto the exterior of the junction box, and is situated on the exterior of the casing.
In particular, the invention concerns a system for cooling an electrical junction box of an electric motor by a cycle gas flow.
In fact, it can be necessary to cool the electrical supply enclosure (junction box) of an electric motor or turbomachine.
This junction box is often spaced from the gas circulation or the cooling water radiator of the central part of the associated motor or turbomachine.
In known solutions, this box is cooled by natural convection, by conduction by the walls of the junction box. In addition, the heat is controlled by dimensioning of the junction box, and increase of its surface area in contact with the ambient temperature, of the diameter of the cables, and of the size of the spark plugs or electrical connectors. These measures increase the global size of the junction box, its weight, its production cost, and the risks of leakage.
In addition, as a result of its capacity to retain the pressure, the thickness of the walls of a box of this type limits its cooling by conduction.
An objective of the present invention is to eliminate some or all of the disadvantages of the prior art indicated above.
In an effort to overcome the deficiencies of the prior art discussed, supra, the device according to certain embodiments of the invention, which is moreover in conformity with the generic definition given by the above preamble, is substantially characterized in that the device comprises a duct for conveying cycle gas under pressure, comprising a first end which is connected to a portion of the circuit in which the cycle gas is at a pressure higher than the minimal pressure, and a second end which communicates with the interior of the junction box, the junction box comprising a passage for communication with the interior of the casing, the fluid circuit comprising a cycle gas return duct, comprising a first end which communicates with the interior of the casing, and a second end which is connected to the circuit, the conveying duct, the passage and the return duct being configured to collect a fraction of the cycle gas which flows in the circuit, in order to make it circulate in the junction box so as to cool the box before returning to the circuit.
In addition, embodiments of the invention can comprise one or a plurality of the following characteristics:
The invention also concerns an installation for refrigeration and/or liquefying, comprising a refrigerator comprising a work circuit of a cycle gas, said circuit comprising, positioned in series, at least one stage for compression of the cycle gas, at least one unit for cooling of the cycle gas, at least one stage for expansion of the cycle gas, and at least one unit for heating of the cycle gas, the installation comprising a circulation gas according to any one of the characteristics above or below, wherein the drive unit comprises a compressor wheel forming a compression stage.
According to other possible distinguishing features:
The invention also concerns a method for cooling an electrical junction box of an electric motor of a circulation device according to any one of the characteristics above or below or of an aforementioned installation, the method comprising a step of collecting a fraction of the fluid flowing in the fluid circuit, and putting this fraction of fluid into circulation in the junction box in order to cool the box, then a step of returning this fraction of fluid to the fluid circuit.
According to other possible distinguishing features:
The invention can also concern any alternative device or method comprising any combination of the characteristics above or below within the context of the claims.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, claims, and accompanying drawings. It is to be noted, however, that the drawings illustrate only several embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it can admit to other equally effective embodiments.
Other particular features and advantages will become apparent from reading the following description, provided with reference to the figures, in which:
The device 1 for circulation of fluid illustrated by way of example in [
The device 1 comprises a casing 2 which is sealed against the exterior of the device, and contains an electric motor 3, and at least one fluid drive unit 4 such as a compressor wheel which is fitted on a shaft 20 rotated by the electric motor 3, in order to form a cycle gas compression stage. The device 1 comprises a cycle gas circuit 5, comprising a downstream portion which is connected to an outlet of the drive unit 4 (outlet of the compression stage for example).
The device 1 comprises an electrical junction box 6 which is sealed relative to the exterior of the device, and in which electrical circuitry 8 passes. The junction box 6 is for example fitted on, or is integral with, the casing 2. For example, the junction box 6 is a box which is distinct from the casing 2, and communicates with the casing 2 via one or a plurality of passages or orifices. Similarly, at least part of the walls delimiting the junction box 8 can be in common, and combined with, at least part of a wall delimiting the casing 2.
The electrical circuitry 8 has a first end which is connected to the motor 3 (via a passage 9 through the box 6 and casing 2 or the like), and a second end which is connected to at least one electrical connector 7 opening on the exterior of the junction box 6. The electrical connector 7 is typically situated on the exterior of the casing 2 (and the device 1 if applicable).
As illustrated, the electrical circuitry 8 which passes in the junction box 6 can comprise an assembly of electrical cables. These cables can be connected to at least one connector 7, for example of the male type, which is fitted and projects for example on a wall or cover which closes the box 6 in a sealed manner (for example via a screw or bolt securing assembly and a sealing system cf. [
The circuit 5 comprises a conveying duct 15 comprising a first end which is connected to a portion of the circuit 5 in which the working gas is not at its minimal pressure in the circuit 5 (typically downstream from a compression stage) and a second end which opens into the junction box 6.
The junction box 6 also comprises at least one passage 9 for communication with the interior of the casing 2 of the motor. If applicable, all or part of the electrical circuitry (cables, etc.) can pass via this passage 9, as schematized in [
The circuit 5 comprises a return duct 25 comprising a first end which communicates with the interior of the casing 2, and a second end which is connected to the circuit 5, in a portion of the circuit in which the working gas is not at its maximal pressure, in particular at a pressure which is equal to, or greater than, the minimal pressure, for example upstream from the compression unit 4. The conveying duct 15, the passage 9 and the return duct 25 are thus configured to collect a fraction of the flow of working gas under pressure flowing in the circuit 5, in order to make it circulate in the junction box 6, so as to cool the box before returning into the circuit 5.
This makes it possible to cool the electrical supply enclosure (junction box 6) of a motor 3 or of a turbomachine, for example by means of a cycle gas flow under pressure put into circulation in the hermetic (or semi-hermetic) part of a junction box 6. This flow of fluid can be made possible by adding and extracting gas (or liquid) through piping, machined cavities and/or cable passages for example.
In particular, as illustrated in [
Preferably, the passage 9 and the first end of the return duct 25 which opens into the junction box 6 are situated at opposite ends of the junction box 6, in order thus to assist agitation and efficient cooling by the cycle fluid flow.
This flow of cooling fluid can be driven by a loss of dynamic load between the point of injection and discharge of the motor or of the piping connected thereto.
As illustrated, preferably, the circuit 5 can comprise a unit 11 for regulation of the flow of fluid circulating in the branching duct 15, for example a valve, a calibrated orifice, or any other appropriate unit (controlled valve for example). The flow regulation unit 11 can be positioned on the conveying duct 15.
As illustrated, the circuit 5 can advantageously comprise a unit 12 for cooling the flow of fluid, such as a heat exchanger, preferably positioned between the circulation unit 4 (compression stage) and the first end of the conveying duct 15. This cooling unit 12 can be a cooling heat exchanger conventionally positioned at the outlet of a compression stage in order to cool the flow of compressed cycle gas (by exchange of heat with a heat-exchange medium, such as water, or another fluid for example).
The fluid circulation device 1 illustrated by way of example in [
The work circuit 5 can comprise, positioned in series, at least one stage 4 for compression of the cycle gas, at least one unit 12, 14 for cooling of the cycle gas (heat exchanger(s) for example, at least one stage 16 for expansion of the cycle gas (turbine(s) or valve(s) for example) and at least one unit 17, 14 for heating of the cycle gas (heat exchanger(s) for example). The compression unit 4 (at least one stage) can comprise a circulation device 1 of the above-described type.
A heat exchanger 12 for cooling of the cycle gas at the outlet of the compression stage can assure cooling of the cycle gas which will be used to cool the junction box 6.
The cooling and heating of the cycle gas can be assured by at least one counter-current heat exchanger 14, which receives a flow of cycle gas at distinct temperatures in the cycle. At its coldest end in the cycle, the cycle gas can be heated by yielding its frigories by heat exchange with a unit to be cooled in a heat exchanger 17 (flow 13 of fluid to be cooled or to be liquefied for example).
The invention can be applied to a device (refrigerator or the like) comprising a plurality of motors 3 each having an electrical junction box 6. Some or all of the motors can comprise a respective cooling system of the type described above. As a variant or in combination, motors can share or pool all or part of the cooling system described above.
In the non-limiting example in [
More specifically, each motor 3 is provided with a respective electrical junction box 6 which communicates with the corresponding casing 2 via passage 9. The conveying duct 15 comprises a first end which is connected to the circuit 5, for example at a downstream portion of the drive unit 4 of a first motor 3 (for example at the outlet of the second cycle gas compression stage).
The device 1 comprises a transfer duct 35 with a first end connected to the casing 2 of the first motor 3, and a second end opening into the junction box 6 of the second motor 3 (of the first compression stage upstream in the cycle gas work circuit). As illustrated, the transfer duct 35 preferably comprises a unit 13 for cooling the flow of cycle fluid, such as a heat exchanger which is cooled by a heat exchange medium (water, air or the like), in order to cool the cycle gas before cooling the second junction box 6.
The return duct 25 comprises a first end which communicates with the interior of the casing 2 of the second motor 3, and a second end which is connected to a portion of the fluid circuit 5, for example upstream from the first compression stage. As schematized in a broken line, the return duct 25 can optionally comprise a unit 25 for cooling of the cycle gas flow (heat exchanger or the like) before it is re-injected upstream from a compression stage.
Thus, the conveying duct 15, the transfer duct 35, the passages 9 and the return duct 25 make it possible to collect a fraction of the compressed cycle gas, in order to make it circulate in series in the junction boxes 6, so as to cool these boxes before returning to the circuit 5.
The example in [
It will be appreciated that the invention can be applied to any other type of installation architecture, and in particular to any type of refrigerator or cryogenic liquefier (typically bringing a working gas to a temperature lower than −150° C.) with one or a plurality of compression stages and expansion stages, with a different number of motors.
The variant of [
In addition, the invention can be applied to a device 1 wherein the motor 3 (or at least one of the motors) is replaced by any other electrical machine, for example an alternator. In this case, the drive unit 4 can comprise a turbine. The turbine(s) 16 can be designed for recuperation of mechanical work which is intended to produce electric power.
Similarly, the first end of the conveying duct can be connected downstream from another unit of the circuit 5, in particular downstream from a unit 4 different from that which is driven by, or coupled to, the electrical machine 3, the junction box 6 of which is to be cooled.
Typically, the first end of the conveying duct(s) 15 is preferably connected to a point of the circuit where the pressure of the cycle gas is higher than the lowest pressure of the cycle gas in the circuit 5. In fact, the cycle gas is subjected in the circuit 5 to thermodynamic transformation (in particular a compression/expansion cycle), between at least two states at low (minimal) and high (maximal) pressures. The cycle gas which is collected in the circuit 5 in order to cool at least one junction box 6 is preferably at a pressure higher than its minimal pressure in the circuit 5.
For example, this cycle gas is collected in the circuit 5 downstream from at least one of the compressors 4 of the circuit 5.
For example, this cycle gas is collected downstream from the compressor 4, which is coupled in rotation on the shaft of the motor 3, the junction box 6 of which is to be cooled. However, this first end of the conveying duct 15 can be connected to the outlet of another compressor 4 (or another unit 4) which is coupled to another motor 3 or electrical machine of the device 1.
Similarly, the second end of the return duct 25 is preferably connected to a portion of the circuit in which the pressure of the cycle gas is relatively low (lower than the maximal pressure), for example at the intake of one of the compressors 4. For example, the return duct 25 is connected to the intake of the compressor 4 which is coupled to (driven by) the motor 4, the junction box 6 of which is cooled by the cycle gas.
In the variant illustrated in [
Conventionally, each motor 3 can comprise a stator 32 and a rotor 31 coupled to a rotary shaft which bears the wheels (compressor(s) 4 and turbine(s) 16).
In this example, two conveying ducts 15 have a first end (which is common in this example) connected downstream from a first one 4 of the two compressors 4 in series, for example downstream from an exchanger 12 for cooling the compressed cycle gas. The second ends of the two conveying ducts 15 are connected in parallel respectively to the two casings 2. The cycle gas under pressure then passes into the junction boxes 6 via the passages 9, and exits from the box 6 and the casing 2 via return ducts 25. The two return ducts 25 can be connected once more to the inlet of a single compressor 4, for example to the first one 4 of the two compressors in series. Thus, the cycle gas under pressure used for cooling of the junction box 6 can previously pass into the corresponding casing 2 before passing into the junction box 6.
As illustrated, the device 1 can also comprise a duct 21 which diverts part of this cycle gas under pressure to a labyrinth system 18 at bearings of the shaft of the motor 3. Typically, this labyrinth system 18 is designed to separate the gaseous atmosphere in the casing 2 from the exterior. In other words, a duct 21 can be connected in parallel to the duct 15 for conveying to a labyrinth (or any bearing system). This duct 21 (just like the conveying duct 15) preferably comprises a valve system 22, which permits opening or closure independently, as required.
In the embodiment in [
Thus, the cycle gas under pressure can be collected by the first end of at least one conveying duct 15 at any appropriate location of the circuit 5, in order to be brought to a junction box 6 directly, or via a casing 2, or the like.
The invention makes it possible to provide compact junction boxes 6, while assuring efficient cooling thereof.
In the case of applications which use frequencies of 100 Hz or more, the electric currents preferably circulate on the surface of the conductive materials. The device is particularly suitable for cooling elements with skin effects of this type, while reducing the temperature of the surfaces.
In the example represented, a single electrical connector 7 is represented, but the invention could be applied to junction boxes 6 comprising a plurality of connections or spark plugs, according to the number of phases of the electric motor and connections or spark plugs necessary to supply power to the electric motor.
The efficiency of the cooling also makes possible a decrease of the cross-section of the cables and other electrical units in the junction box 6.
The invention thus permits improvement of the thermal performance and the resistance to pressure of the electrical junction to a motor.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.
The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.
“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.
Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.
All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2202099 | Mar 2022 | FR | national |
This application is a § 371 of International PCT Application PCT/EP2022/084801, filed Dec. 7, 2022, which claims the benefit of FR2202099, filed Mar. 10, 2022, both of which are herein incorporated by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/084801 | 12/7/2022 | WO |
