WO2009090348A1

WO2009090348A1 - Gas compression apparatus

Info

Publication number: WO2009090348A1
Application number: PCT/FR2008/001493
Authority: WO
Inventors: Gilbert Grasmuck
Original assignee: Airtechnolgies; Peugeot Citroen Automobiles Sa
Priority date: 2007-10-25
Filing date: 2008-10-24
Publication date: 2009-07-23
Also published as: FR2922971A1; FR2922970A1

Abstract

The invention relates to a gas compression apparatus (1) that comprises a gas compression system (2) including a first vaned rotor (11) and a volute (13), an electric motor (3) for driving said vaned rotor (11) assemblies defining air-type bearings (17) for guiding the shaft (12) of the motor (3), and one or more assemblies defining an axial air-type stop (18) and provided on said shaft (12). According to the invention, the apparatus (1) includes: a fan (4) on the side of the motor shaft (12) opposite the side on which the compression system (2) is located, including a second vaned rotor (26) and a volute (21), said second vaned rotor (26) being arranged conversely relative to the first vaned rotor (11), as well as ducts (5, 6, 7) for distributing pressurised air generated by the fan (4) towards the air bearing assemblies (17), the air stop assembly or assemblies (18), and the motor (3) of the apparatus (1).

Description

GAS COMPRESSOR APPARATUS COMMONLY NAMED

TURBOMACHINE

The present invention relates to a gas compression apparatus, commonly referred to as "turbomachine". Such an apparatus comprises a gas compression system, including a finned wheel, a volute in which is placed this finned wheel, and an electric motor driving in rotation of the high speed finned wheel. An apparatus of this type can be used, for example, as a supply source for a pressurized air fuel cell or as a pressurized air generator in a vehicle ventilation system, in particular in the vehicle ventilation system. ventilation of the cabin of an aircraft, or the driving of a set called "turbocharger" vehicle.

In view of the high rotational speed of the rotor, which is driven with respect to the present invention by an electric motor, and the need in some applications to deliver air free of all grease particles, it is appropriate, and known , to use assemblies forming air bearings, also called "foil air bearing assembly" (English) to guide this shaft, and one or more sets forming an axial abutment, also air ( "air thrust bearing assembly" in English), opposing the axial thrust exerted on the motor shaft by the pressurized gas generated by the compression system.

These sets of bearings and stop assembly (s), as well as the electric motor, of such an apparatus undergo a significant heating during operation of the apparatus. At the level of the bearing assemblies and the abutment assembly (s), the friction at the level of the air film generates a significant heating. It is then necessary to avoid overheating the constituent materials of the sheets and / or dampers, which are sensitive to the temperature. At the rotor and stator motor, in addition to joule losses and eddy current losses generated in the stator, the heat generated by shearing motor due to high rotation speeds. This important heating also makes it imperative to cool the bearing assemblies and stop assembly (s) as well as the engine, failing which these bodies could be damaged or have reduced service life. According to an existing technique for cooling such an apparatus, cooling air is provided by an external source of cooling air.

However, this technique has the disadvantage of making the device relatively complex and have a significant impact on the energy efficiency, cost and reliability of the latter.

According to another existing technique for cooling such an apparatus, gas is taken at the outlet of the compression system, is cooled by means of an external cooling unit, and is then introduced into a cooling circuit. The temperature of this gas is high, which forces to provide said external cooling unit. The latter has a significant impact on the overall energy efficiency, complexity, size, reliability and cost of the device, which limits the possibilities of use of this device. In addition, the cooling performed may not be sufficient, which affects the service life of the bearing assemblies, stop assembly (s) and motor, which limits the use of this technique in many applications.

According to yet another existing technique, a gas flow is arranged through a gap arranged at the level of the shaft carrying the compression wheel. This flow may not be sufficient for adequate cooling of the apparatus because of the high temperature of the air taken.

The problem of good cooling of a device as mentioned above is therefore a problem not perfectly solved to date. When such an apparatus does not have a drive turbine, another disadvantage of this apparatus lies in the aforementioned axial thrust exerted on the motor shaft by the pressurized gas generated by the compression system, which involves the presence of the or abutment assembly (s) above, which themselves undergo a significant effort. It would be advantageous to be able to reduce this effort, in order to reduce the requirements relating to this or these abutment assemblies, as well as their heating, and thus to prolong the service life of the apparatus and / or increase the performance of it.

The main objective of the invention is therefore to provide an apparatus as mentioned above, whose cooling is provided under the best conditions and whose performance and / or the possibilities of use are increased. Another object of the invention is to provide such an apparatus, the thrust assembly of the motor shaft is subjected to a lower axial force than in an existing apparatus.

Yet another object of the invention is to provide a cooling solution that is simple to implement, self-controlled and has a minimized energy impact on the apparatus.

The apparatus concerned comprises, in a manner known per se, a gas compression system, comprising a first finned wheel and a volute, an electric motor for driving this finned wheel, assemblies forming air-type bearings , guiding the motor shaft, and one or more sets forming an air-type axial stop, placed on this shaft.

According to the invention, the apparatus comprises:

a fan on the side of the motor shaft opposite to that on which the compression system is located, including a second impeller and a volute, this second impeller being arranged inversely with respect to the first impeller; fins, and

- ducts for distributing the pressurized air generated by the fan to the air bearing assemblies, the air stop assembly (s) and the engine of the apparatus. This fan thus constitutes a self-contained internal source of pressurized cooling air taken from outside the apparatus, and the distribution ducts supply this air directly to the bearing assemblies. or the air brake assemblies and the engine of the apparatus, for optimum cooling thereof. The cooling air is at a temperature significantly lower than that of the apparatus, eliminating the need for an external cooling unit for this air.

In addition, the apparatus has a structure remaining relatively simple, and a size, reliability and cost significantly increasing its potential for use, especially for application to the supply of a fuel cell pressurized air.

In addition, said second impeller, by its inverted arrangement with respect to said first impeller, counterbalances part of the axial thrust exerted on the shaft by this first impeller, and thus reduces the requirements. relating to the abutment assembly (s) placed on this shaft, as well as the warming experienced by them. Preferably, the rotation of said second fin wheel is slaved to the rotation of said first fin wheel, so that it is possible to design a ventilation wheel geometry to adapt the need for air flow of cooling at all operating conditions of the device. Advantageously, in this case, said second finned wheel is mounted on an extension of the motor shaft.

Said distribution ducts advantageously comprise a duct for conveying the cooling air from the volute of the fan, a series of air passages connected to this duct, conveying the cooling air around the engine, and at the level of the assemblies. bearings and the abutment assembly or assemblies, and a duct connected to these passages, for evacuating this cooling air.

Said second impeller may be devoid of a flange connecting the free edges of its fins, or may include such a flange, to improve the energy efficiency of the device, but at the expense of balancing axial thrust.

The invention will be better understood, and other features and advantages thereof will become apparent, with reference to the accompanying diagrammatic drawings, showing, by way of non-limiting example, a preferred embodiment of the apparatus to which it relates. .

Figure 1 is a longitudinal sectional view through the axis of the shaft of an engine that includes this device; Figure 2 is a view similar to Figure 1, partial and on an enlarged scale, showing the cooling fan that includes the device; Fig. 3 is a perspective view of a finned cooling wheel which can be understood by the apparatus, and Fig. 4 is a perspective view of another finned cooling wheel which can be understood by the apparatus.

FIG. 1 represents an air compression apparatus 1, commonly referred to as a "turbomachine", comprising a system 2 for compressing air, an electric motor 3, a fan 4 and ducts 5, 7 and passages 6 for distributing the air. pressurized air generated by the fan 4 to different organs of the apparatus.

The air compression system 2 comprises an air intake manifold 10, a finned wheel 11 mounted on the shaft 12 of the engine 3, a volute 13 in which is placed the wheel 11, and a pipe (not visible) outlet of the air under pressure. The system 2 may also comprise, in the volute 13, a diffuser with steerable vanes (not shown). All of these elements are known and are not in themselves the object of the invention, so it will not be described in more detail.

The motor 3 comprises, besides the shaft 12, a rotor 15 and a stator 16, air-type bearing assemblies 17 and an assembly 18 forming an air-type axial abutment, making it possible to contain the thrust exerted on the air shaft. 12 by the compression of the air generated by the compression system 2. This motor 3 is placed in a housing 20 which internally forms the passages 6 for circulating the cooling air generated by the fan 4. These passages 6 are connected, on the one hand, to the duct 5 for conveying the cooling air from a volute 21 that includes the fan 4, and, on the other hand, the duct 7 for discharging this cooling air. The passages 6 convey the cooling air into the chamber of the housing 4 containing the engine 3, at the level of the bearing assemblies 17 and at the level of the stop assembly 18.

The fan 4 is situated on the side of the shaft 12 opposite to that on which the compression system 2 is located. It comprises, in addition to the volute 21, an air intake pipe 25 and a fin wheel 26, this wing wheel 26 being mounted on an extension of the shaft 12, inversely with respect to the impeller 11.

The volute 21 is contiguous to a wall that includes the housing 20 and is provided with a gap at its bottom, around the shaft 12, so that a portion of the air flow under pressure that generates the fan 4 operates, by air leakage through said gap, a direct cooling of a bearing assembly 17 located near this volute 21.

Figures 3 and 4 show the impeller 26, which may be devoid of a flange connecting the free edges of its fins (Figure 3), or include such a flange 27 (Figure 4).

As it appears, the fan 4 constitutes an independent source, internal to the apparatus 1, of pressurized cooling air taken from the outside of the apparatus 1, and the ducts and passages 5, 6, 7 of distribution ensure directing this air directly to the bearing assemblies 17, the stop assembly 18 and the motor 3, for optimum cooling thereof. Looks like cooling is at a temperature significantly lower than that of the apparatus 1, which eliminates the need for an external cooling unit of this air. The apparatus 1 has a structure remaining relatively simple, and has a size, reliability and cost significantly increasing its potential for use, especially for application to the supply of a fuel cell pressurized air.

In addition, the impeller 26, by its inverted arrangement with respect to the impeller 11, makes it possible to counterbalance part of the axial thrust exerted on the shaft 12 by this wheel 11, and thus to reduce the requirements relating to to the abutment system 18, as well as the warming experienced by it.

The invention thus provides a gas compression apparatus, having, compared with prior art homologous apparatus, the decisive advantages of having assured cooling under the best conditions and increased performances and / or possibilities of use, and to have an engine shaft thrust system undergoing less effort than in an existing apparatus.

The invention has been described above with reference to a given embodiment as a pure example. It goes without saying that it is not limited to this embodiment but that it extends to all the embodiments covered by the appended claims.

Claims

1 - Apparatus (1) for compressing gas, comprising a gas compression system (2), which includes a first impeller (11) and a volute (13), an electric motor (3) for driving this gas finned wheel (11), assemblies forming air-like bearings (17) for guiding the shaft (12) of the motor (3), and one or more sets forming an axial stop (18) of the air, placed on this shaft (12), and a fan (4) on the side of the shaft (12) of the motor opposite to that on which is the compression system (2), including a second impeller (26). and a volute (21), said second vane wheel (26) being inverted with respect to the first vane wheel (11); characterized

in that the fan (4) comprises a volute (21), and

- ducts (5, 6, 7) directly connected to the volute (21), distribution of the pressurized air generated by the fan (4) to the sets (17) of air bearings, the or sets ( 18) and the motor (3) of the apparatus (1).

2 - Apparatus (1) according to claim 1, characterized in that the rotation of said second impeller (26) is slaved to the rotation of said first impeller (11). 3 - Apparatus (1) according to claim 2, characterized in that said second finned wheel (26) is mounted on an extension of the shaft (12) of the motor (3).

4 - Apparatus (1) according to one of claims 1 to 3, characterized in that said distribution ducts comprise a conduit (5) for conveying the cooling air from the volute (21) of the fan (4) , a series of air passages (6) connected to this duct (5), conveying the cooling air around the motor (3) and at the level of the bearing assemblies (17) and the abutment assembly (18). ), and a duct (7) connected to these passages (6) for discharging this cooling air. 5 - Apparatus (1) according to one of claims 1 to 4, characterized in that said second impeller (26) is devoid of a flange connecting the free edges of its fins.

6 - Apparatus (1) according to one of claims 1 to 4, characterized in that said second impeller (26) comprises a flange (27) connecting the edges of its fins.