FR3075251B1 - VOLUMETRIC MACHINE WITH SPIRALS - Google Patents

Abstract

The present invention relates to a spiral volumetric machine comprising: - a first fixed structure (2) formed by a first transverse disc end plate (2001) whose one of the surfaces forms a spiral bottom, surmounted by a wall defining a first spiral (2002), said end plate (2001) having a first central opening (407) - a second movable structure (3) formed by a second transverse disc end plate (3001), one of whose surfaces forms a spiral bottom, surmounted by a wall defining a second spiral (3002), the wall thickness of each of said spirals (2002, 3002) varies between a constant nominal thickness on an intermediate portion extending over more than one turn, and a reduced thickness, at said upper indentations (409, 313), in a central end portion extending between 60 ° and 120 ° from the inner primer of the spiral, said reduced thickness being less than 50% of said nominal thickness.

Description

VOLUMETRIC SPIRAL MACHINE

Field of the invention

The present invention relates to the field of volumetric machines, in particular compression machines or expansion machines. These machines can be:

• turbomachinery using the kinetic energy of gas • volumetric machines, using a change in gas volume. Volumetric machines can be piston, spiro-orbital, screw, etc.

The present invention relates more particularly to the field of volumetric spiro-orbital machines (in English "scroll"), in both forms of use, as a compressor (used for example, as an air compressor or in an air conditioning cycle, refrigeration or in a heat pump (sometimes referred to as "compressor G") or as an expansion machine (used for example in an organic Rankine cycle).

Such a machine comprises a movable part in the form of a spiral performing an orbital movement relative to another fixed spiral substantially identical to the first. These two spirals are 180 ° out of phase. In a compressor use, the spaces formed between the two spirals constitute chambers of geometry and evolutionary position, gradually reduce as the orbital movement of the movable spiral progresses to open out towards the central delivery port, and vice versa in when used as an expansion machine, the chambers gradually grow to open laterally at the periphery.

This type of volumetric machine has a reduced noise level, great flexibility of use with a wide range of speeds, good performance, great robustness and continuous operation at almost constant torque.

For such spiro-orbital machines, one of the difficulties relates to obtaining high volume ratios between the volume of the chambers just before the exhaust and the volume of the chambers just after admission, while accepting high pressures and temperatures which stress the spirals significantly.

State of the art

The European patent EP0814266 is known in the state of the art, presenting an apparatus for moving fluids of the spiral type comprising:

an enclosure having a fluid inlet port and a fluid outlet port;

- fixed and orbital spiral members each having an end plate and a spiral element extending from one side of said end plate, said spiral elements mutually adjusting with angular and radial offset in order to produce a plurality of contact lines defining at least one pair of closed fluid chambers;

- a drive mechanism comprising a drive shaft supported, so as to be able to rotate, by said casing to cause the orbital movement to effect on said spiral member by the rotation of said drive shaft so as to thereby change the volume of said chambers fluids. According to this document, the inner end of said spiral element of each of said spiral members has an area of axial section which changes from root to tip, and has an extension to the transition between the root and the end plague.

Disadvantages of the prior art

In the solutions of the prior art, it is observed that the movable spiral has a significant thickness at its internal initiation leading to a partial closure of the central orifice of the fixed spiral, upon admission for an expansion machine, or during discharge for a compressor type machine. The consequence is degraded performance.

Furthermore, the thickness of the spiral at its inner initiation reduces the feed section defined by the spacing of the sides of the spirals in cooperation with the chamber in formation in the hollow of the movable spiral (so-called “indirect” pocket). , for an expansion machine, or reduces the delivery section of the through chamber in the case of a compressor. The consequence is also a degradation of performance.

Solution provided by the invention

In order to respond to these drawbacks, the present invention relates, in its most general sense, to a volumetric spiral machine comprising:

a first fixed structure formed by a first transverse disc end plate, one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a first spiral, said end plate having a first central orifice, a second movable structure formed by a second transverse disc end plate, one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a second spiral, said second structure moving relative to said first structure in an orbital movement, said elements in spirals mutually adjusting with an orbital offset to provide a plurality of contact lines defining at least one pair of closed fluid chambers, the volume of said fluid chambers varying as a function of the relative position of one of said structures with respect to at the other structure, an inner end of said spiral element p having an upper indentation extending from the surface opposite the plate to an intermediate section characterized in that the thickness of the wall of each of said spirals varies between a constant nominal thickness on an intermediate part extending over more '' a turn, and a reduced thickness, at the level of said upper indentations, in a central extremal part extending between 60 ° and 120 ° from the inner initiation of the spiral, said reduced thickness being less than 50% of said nominal thickness .

According to an advantageous variant, the central orifice of said first end plate has an oblong shape, one of the ends of said central orifice of oblong shape intersecting the transverse projection of the non-indented intermediate zone of the spiral, and the extremal zone of the spiral surmounting said first end plate having a lower indentation extending from the periphery of said end of the oblong orifice to the unindented median zone of the spiral.

According to another variant, at least one of said transverse disc end plates has in a peripheral annular zone a plurality of cavities separated by bridges and hollowed out relative to the spiral bottoms of said disc end plates.

According to another variant, the internal edges of said cavities are located on a line offset radially by less than 60% of the thickness of the wall of the spiral when the internal surface of the peripheral end of the opposite spiral is projected, when the peripheral chamber formed between the two spirals opens out.

Advantageously, the width of said cavities measured in the radial direction is greater than the thickness of the wall of the opposite spiral.

Preferably, the depth of said cavities is greater than 0.5 millimeters.

According to another variant, the upper front surface of at least one of said spirals has a central groove for positioning a joint.

According to a particular embodiment, the upper front surface of at least one of said spirals has, on the internal edge, notches opening into said median groove.

According to a particular variant, said notches of the spiral of one of said structures are positioned to communicate, during the orbital movement, with the cavities formed in the disc end plate of the complementary structure.

Advantageously, the fixed and mobile spirals both have a fillet at the foot of the central end of the spiral profile as well as a chamfer in their central zone.

Detailed description of a nonlimiting example of the invention

The present invention will be better understood on reading the detailed description of a nonlimiting example of the invention which follows, referring to the accompanying drawings in which:

- Figure 1 shows an exploded view of a

expansion machine according to the invention;

- Figure 2 shows a perspective view interior and exterior of the whole spiral cover;

- Figure 3 shows a longitudinal sectional view of the machine;

- Figure 4 shows a front view of fixed and movable spirals of the machine r

- Figure 5 shows the position of the fixed and movable spirals during rotation of the machine shaft;

- Figure 6 shows a perspective view

partially cut off from the moving part of the machine;

- Figure 7 shows a perspective view

partially cut off from the machine housing assembly;

- Figure 8 shows a perspective view partially cut off from the assembly coupling

machine;

- Figure 9 shows front views of

different variants of the axial abutment surface;

- Figure 10 shows a schematic view of the lubrication of the machine;

- Figure 11 shows a schematic view of a Rankine cycle according to the invention;

- Figure 12 shows a schematic view of a high temperature heat pump according to the invention;

- Figure 13 shows schematic views of design details present on the spirals;

- Figure 14 shows three section views of the assembly constituting the movable spiral and the fixed spiral at three different stages of the expansion cycle;

- Figure 15 shows views of the shaft and the counterweight of the machine;

the figure 16 represented a front view of a variant of form from the port of admission; - the figure 17 represented a sectional view of the spirals then of the exhaust; - the figure 18 represented a graph showing 1'impact a of the points of design < of the spirals; - the figure 19 represented a variant of the

thrust washer having an annular backpressure chamber;

- Figure 20 shows a sectional view of the central area formed by the spirals.

As previously described, the invention relates to spiro-orbital volumetric machines, both for expansion machine type applications and for compression machine type applications.

General principle of using the machine as an expansion machine

An expansion machine, within the meaning of the present invention, produces a rotary mechanical movement by transformation of the energy coming from a working fluid under pressure.

The transformation is carried out in an expansion chamber, or several expansion chambers, forming an expansion zone, supplied with working fluid in vapor form charged with lubricant, coming from the high-pressure intake zone and discharged by an exhaust zone. The pressurized fluid comprises a main component such as ethanol or cyclopentane or a refrigerant rl233zd (E) or rl336mzz (Z), ensuring the thermodynamic cycle, charged with a liquid lubricant sprayed in the vapor phase of the main component. The lubricant is for example of the polyalkylene glycol (PAG) or polyolester (POE) type miscible in the liquid phase with the other components. The proportion of lubricant is typically between 1 and 20% by mass.

In the case of the use of ethanol, this working fluid may also comprise components such as water, in a proportion of between 0 and 20% by mass and optionally additives for denaturing the ethanol, by example of the euro-denaturant (trade name), or an alkane, or methanol, or a ketone in proportions of between 1 and 10% by mass.

In nominal operation, the expansion machine operates according to the general principle of the expansion step of a Rankine or Hirn cycle.

General principle of the use of the machine in compression machine

A compression machine, within the meaning of the present invention, compresses a gaseous working fluid by transformation of the energy originating from a rotary mechanical movement.

The transformation is carried out in a compression chamber or several compression chambers forming a compression zone, supplied with working fluid in gaseous form charged with lubricant, coming from the low-pressure admission zone and evacuated by an exhaust zone. high pressure. The fluid comprises a main component such as a refrigerant R1336mzz (Z) or R1233zd (E), ensuring the thermodynamic cycle, charged with a liquid lubricant sprayed in the vapor phase of the main component. The lubricant is for example of the polyalkylene glycol (PAG) or polyolester (POE) type miscible in the liquid phase with the other components.

In nominal operation, the compression machine operates on the general principle of the compression step of a refrigeration cycle.

General principle of spiro-orbital volumetric machines

In known manner, volumetric spiroorbital machines comprise two complementary structures (2, 3) with a relative displacement of the orbital type.

The first structure is a fixed structure (2) formed by a first transverse disc end plate (2001), one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a first spiral (2002). This end plate (2001) has a first central opening (407).

The second structure (3) is movable relative to the fixed structure (2). It is formed by a second transverse disc end plate (3001), one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a second spiral (3002).

The second structure (3) moves relative to the first structure (2) in a circular translation, called orbital movement. The movement is characterized by a plane in which the movement takes place and an eccentricity. The plane is defined by the front surface of the second disc end plate (3001) on the side opposite the second spiral (3002). Finally, “eccentricity value” is understood to mean the maximum offset between the fixed structure (2) and said mobile structure (3).

The spiral elements (2002, 3002) mutually adjust with an orbital offset to provide a plurality of contact lines defining at least one pair of closed fluid chambers (411, 419, 420, 423, 424). The volume of these fluid chambers varies as a function of the relative position of one of said structures (2) with respect to the other structure (3).

The inner end of the spiral element (2002, 3002) has an upper indentation respectively (409, 313) extending from the surface opposite the plague (2001, 3001) to an intermediate section (2003, 3003 ).

General architecture of an embodiment of a spiro-orbital volumetric machine according to the invention

Figures 1, 11 and 12 respectively show an exploded view of a spiro-orbital volumetric machine according to an example of the invention, as well as a schematic view of a Rankine cycle and a high temperature heat pump according to the invention.

The spiro-orbital volumetric machine (804, 850) has an external body formed by two complementary hollow parts:

- a spiral cover assembly (400);

- a housing assembly (200).

These of them additional parts (400, 200) each present a cylindrical flange (401, 201) complementary, for allow assembly of way

waterproof by bolting.

A movable hitch (300) mistletoe will be described in more detail in this following mistletoe is fully enclosed in the volume defined by the spiral cover assembly (400) and the housing (200).

The spiral cover assembly (400) surrounds the expansion zone when it is an expansion machine, or compression when it is a compression machine, which extends from the port (19) inlet, respectively discharge, of steam to the support of the axial stop on the fixed part (220). This is the hottest part of the machine (804, 850). This zone includes in particular the fixed structure, also called fixed spiral (2), with which the mobile structure, also called mobile spiral (3), comes into contact. This contact is intended to guide the mobile spiral in its orbit movement.

The housing (200) surrounds the area of the machine (804, 850) which extends from the support of the axial stop (220) to the end of the shaft (13). This zone comprises in particular a shaft (13) and a coupling device (500) of said machine.

The movable coupling (300) comprises the shaft (13) and the members attached to it:

- a camber (26), ensuring the connection between an eccentric pin (314) of the shaft (13) and a counterweight (14);

- the counterweight (14), ensuring the connection with the hub (320) of the movable spiral (3);

- the spiral mobile (3), whose hub ( 320) East eccentric compared to 1 'shaft (13), , this ensuring than his movement either orbital; - a ring anti rotation (12), ensuring than the

movable spiral (3) does not rotate around the axis of its hub (320), while allowing circular translation of the movable spiral (3) in the transverse plane;

- the coupling device (500) of the machine, consisting in particular of a toothed wheel (10) and a freewheel (30);

- bearings, for example needle, ball or roller bearings.

In operation in an expansion machine (804), in FIG. 11, the working fluid (808) in the form of vapor enters the spiral cover assembly (400) via the steam inlet port (19) at a temperature below 250 ° C generally between 180 ° C and 235 ° C. This vapor is charged with lubricant.

The lubricant travels in a known manner throughout the Rankine circuit, driven by the working fluid (808).

This working fluid (808) is for example composed of a mixture of ethanol, water, denaturant and lubricant. The percentage of water is between 0 and 20% by mass, preferably 4.5% by mass (azeotrope). To this mixture is added a denaturant, for example an alkane, an alcohol, a ketone or 1 euro-denaturant (standard mixture) between 1% by mass and more (2% euro-denaturant by volume) to which lubricant is added. of polyalkylene glycol (PAG) type miscible between 1 and 20% by mass, generally about 5 to 10%.

The working fluid (808) in the form of vapor arrives via an inlet connection or a flange provided on the center of the spiral cover assembly (400) and exits, in the example described, on the side by a flange exhaust (21) provided on the spiral cover assembly (400).

Steam circulates between the fixed spiral (2) and the mobile spiral (3) to activate the orbital movement of the mobile spiral (3) as will be presented in more detail in the following description.

In operation in a compression machine (850), as illustrated in FIG. 12, the working fluid (808) in the form of vapor enters the spiral cover assembly (400) via the steam intake flange (21). This vapor is charged with lubricant.

The working fluid (808) in the form of vapor leaves the center through the exhaust flange (19) or an outlet fitting provided on the spiral cover assembly (400), compressed and at a temperature below 250 °. C generally between 90 ° C and 235 ° C.

The lubricant travels in known manner throughout the refrigeration circuit, driven by the working fluid (808).

This working fluid (808) comprises a main component such as a refrigerant R1336mzz (Z) or R1233zd (E), ensuring the thermodynamic cycle, charged with a liquid lubricant sprayed in the vapor phase of the main component. The lubricant is for example of the polyalkylene glycol (RAG) or polyolester (POE) type miscible in the liquid phase with the other components.

The compressed working fluid (808) is then admitted into a condenser (854), then into a pressure reducer (855) and finally into an evaporator (853) in order to be readmitted to the inlet of the compression machine (850) . Pressure and temperature sensors (860 and 861) can be implemented respectively at the input and output of the compression machine (850).

The energy required to compress the working fluid (808) is obtained by a rotary machine (851), which can be an electric motor. The rotation of the shaft (813) of said machine is then transmitted to the compression machine (850) via a transmission (852), which can be effected by a pulley-belt type connection. Compared to the case described in Figure 12, the transmission (852) can also be arranged between a seal (70) and a rear bearing (104), in a configuration similar to that presented in Figure 11.

In the following description, the machine will be presented in the particular mode of operation as an expansion machine in order to simplify the description. Those skilled in the art will be able to interpret this description to extend it to the particular mode of operation in a compression machine.

Detailed description of the spiral cover

FIGS. 2 and 3 respectively represent an interior / exterior perspective view of the head covering assembly as well as a longitudinal section view of the machine.

In the example described, the spiral cover (4) is made of cast iron, in particular a cast iron of lamellar graphite type resistant to ethanol.

The part is produced by foundry in a mold and by machining the various orifices and cavities, then it can be the subject of a surface treatment by nitriding in a salt bath followed by an oxidation phase, or alternatively d 'a manganese phosphate phosphating treatment.

The exterior of the spiral cover (4) has the central intake port (19), to which an inlet fitting or flange can be connected. The fixed spiral (2) is pierced in its center (407) so that the working fluid in the form of vapor (808) under pressure admitted via the intake port (19) can access a central chamber (411) between the fixed spiral (2) and the mobile spiral (3).

The exterior of the spiral cover (4) has an opening for a speed sensor (54). The speed information is taken using a Hall effect sensor, detecting the passage of a moving part, preferably the anti-rotation ring (12) or the moving spiral (3).

The exterior of the spiral cover (4) has, on a side wall, an exhaust orifice surrounded by the flange (21) forming an annular receiving surface for receiving a seal.

Two threads (412 and 413) allow to receive fixing screws for a flange of an exhaust pipe. This flange (21) is located in the lower lower half of the expansion machine (804) when the latter is mounted on an associated rotary machine (801). Its exact position is determined according to the machine (801), to facilitate the purging of the working fluid (808) stagnating in the machine at standstill and the connection to a condenser (805) of the Rankine cycle. Also, its orientation is preferably such that its orifice is oriented in a direction opposite to the rotary component of the flow of working fluid in the form of vapor (808) at the outlet of the spiral, and this in order to limit the outlet of the oil carried by said vapor.

The exterior of the spiral cover (4) has, in parallel with its intake circuit, a bypass valve (in English, bypass valve) (59) intended, once actuated, to redirect the flow steam directly to a low pressure zone (817) via a volume (418) located behind the fixed spiral (2), without passing between the spirals (2 and 3). This bypass circuit ensures in particular the purging of the working fluid (808) stagnating in the stopped machine.

The exterior of the spiral cover (4) also has several axially oriented cylindrical bosses (404), receiving a thread intended for fixing the fixed spiral (2).

The exterior of the spiral cover (4) also has several ribs (405), which ensure the rigidity of the bottom and avoid deformations resulting from the vapor pressure.

The exterior of the spiral cover (4) has one or more bosses (53) for positioning sensors, for example temperature or pressure sensors.

The bottom of the spiral cover (4) has a cylindrical cavity (414) ensuring the centering of the fixed spiral (2) while the indexing in rotation is done using a shouldered screw or a pin ( 102). The fixed spiral (2) is maintained by screws (100). These screws (100) also make it possible to compress the high temperature flat seal (6), which provides sealing at the rear of the fixed spiral (2) between the central chamber (411) and the volume of the bypass circuit. (418). The volume (415) inside the flat seal (6) is loaded with high pressure steam, this mistletoe makes it possible to reduce the bending of the fixed spiral (2) subjected to the pressure. The flat seal (6) is made of expanded polytetrafluoroethylene, this mistletoe allows it to ensure its sealing function at high temperatures (up to 250 ° C) as well as at high pressures (up to 35 bar) . Its thickness is between 1 and 4 millimeters, and its compressibility is between 10 and 70%.

The spiral cover (4) has inclined holes (402) intended to collect the oil from the steam (808), the latter naturally collecting on the walls by centrifugation. The oil collected via the holes (402) then flows through associated holes (204) in a casing (5).

The spiral cover (4) has the peripheral flange (401) allowing its bolting, centering and sealing on a casing part (200). Sealing is ensured by a torigue seal (74) whose properties are detailed in the description of the housing assembly (200).

Detailed description of the spirals

FIG. 4 represents a front view of the fixed spiral (2) on the left and of the mobile spiral (3) on the right, as well as several views of details.

FIG. 5 represents the positioning of the spirals during a steam expansion cycle for 1 revolution of the expansion machine.

FIGS. 13 and 14 respectively represent a perspective view of the specific features of the centers of each spiral, as well as views showing the role of these specific features at several stages of the steam expansion cycle.

Figures 16, 17 and 20 respectively show a view of a variant form of steam inlet port, views detailing the operation of the exhaust ports of the spirals, as well as a sectional view of the central area of the spirals .

Note that the general profile of the movable spiral (3002) is symmetrical to that of the fixed spiral (2002).

In the example described, the radial guidance between the two spirals is said to be accommodating (“compiling” in English). The mobile spiral (3002) is in fact always in contact radially with the fixed spiral (2002) via the sealing points (416), visible in a step 601 of FIG. 5.

It is known that the sealing in the radial direction of the different steam chambers located between the movable spiral (3) against the fixed spiral (2) is obtained by pressing the profiles of the movable spiral (3002) against those of the fixed spiral (2002). This plating effort is commonly called sealing effort.

Pressurized steam (808) is admitted to the central chamber (411) via the central bore in the fixed spiral (407). The pressure of this central chamber (411) pushes the movable spiral (3), increasing the volume of said central chamber. The volume of this chamber (411) increases until a step 606 in FIG. 5, where the central chamber (411) is split into two symmetrical chambers (419 and 420). The relaxation then continues in these two symmetrical chambers (419 and 420) until the exhaust.

The pressure of the steam chambers located between the two spirals creates a tangential force on the mobile spiral (3), the latter describing an orbital movement around the shaft (13). This orbital movement is then transformed into a rotary movement by means of the eccentric pin (314) of the shaft (13).

In the example described, the spiral profile extends over three and a half turns in order to obtain the optimum volume ratio between the volume just before the exhaust and the volume just after admission for the type of operation targeted. The geometry of the spirals (2 and 3) is adjusted according to the input parameters of the expansion machine (804). These parameters can be the pressure of the working fluid (808), its flow rate, its temperature, the type of fluid used or the speed of rotation of the expansion machine (804) in particular.

In the example described, the spirals (2 and 3) are not in contact in the axial direction. To limit leaks due to this axial play, spiral-shaped sealing segments (“tip-seal” in English) (17 and 18) are mounted in grooves provided for this purpose (408 and 308). These segments (17 and 18) are made of polyetheretherketone (PEEK), in a shade resistant to temperatures ranging over 250 ° C, with a thickness typically between 1 and 4 millimeters.

The spirals (2 and 3) each have two studs (403 and 302) in contact with the anti-rotation ring (12). The tangential force of the mobile spiral (3) is transmitted to the anti-rotation ring (12) by its studs (302). The ring is locked in rotation by the fixed spiral (2) by means of two studs (403), it follows that the induced rotation of the mobile spiral (3) relative to the fixed spiral (2) is impossible . However, the studs (403 and 302) being positioned perpendicularly to one another, it follows that the movement of the movable spiral (3) is possible on the plane of the axial stop (220) .

The studs (403 and 302) have at their corners chamfers (311) of small angle, typically between 1 degree and 5 degrees, visible in the detail view B of FIG. 4. These chamfers are intended to create an effect hydrodynamic beneficial for the lubrication of the sliding contact between the studs (403 and 302) of spirals and the anti-rotation ring (12).

The movable spiral (3) also has two additional pads (306), of height less than the guide pads of the ring (302). These studs (306) limit the movement of the anti-rotation ring (12) in the axial direction.

The movable spiral (3) has a cavity (304) and a projection (305) intended to bring the center of gravity of the part back onto the axis of its hub (320). This balancing eliminates inertial torque fluctuations of up to 50% of the maximum torque delivered by the machine.

The fixed and mobile spirals (2 and 3) have cavities (303 and 406). These cavities (303 and 406) are positioned so as to increase the exhaust passage section without modifying the volume ratio previously described and have the effect of reducing the work consumed by the machine during the discharge phenomenon. FIG. 17 shows the operation of these cavities (406) at the time of the opening of the last two symmetrical chambers (423 and 424), that is to say close to step 601 as shown in FIG. 5: the vapor flow (808) then begins to escape through its “natural” opening (422) formed by the relative movement of the two spirals (2002 and 3002), but also by its openings formed by the spiral slots (312) and the cavities (406). These cavities (303 and 406) are symmetrical in order to form the same section of passage for the exhaust for the two symmetrical chambers (423 and 424). These cavities (303 and 406) are broken down into several parts in order to present "bridges" (425) ensuring that the sealing segments (17 and 18) of the spirals are held in their groove (308 and 408).

The fixed and mobile spirals (2002 and 3002) have notches (312) machined at the level of the segment groove. These notches, visible in detail C in FIG. 4 and in FIG. 17, are positioned so as to be coincident with the cavities (303 and 406) during discharge, and thus increase the exhaust flow for the same purpose as the cavities (303 and 406). The exhaust flow is represented by arrows in FIG. 17. The notches (312) are machined in several parts in order to hold the sealing segments (17 and 18) correctly in their grooves (308 and 408).

FIG. 18 shows the evolution of the forces generated by the steam (808) throughout a rotation of the expansion machine (804) according to the invention. The curves FT1 and FRI respectively designate the tangential and radial vapor force (808) applied to the movable spiral (3) in the presence of the cavities (303 and 406) as well as the notches (312). The curves FT2 and FR2 respectively designate the tangential and radial vapor force (808) applied to the movable spiral (3) without the presence of the cavities and slots. FIG. 18 shows that the presence of the cavities (303 and 406) as well as of the notches (312) makes it possible to reduce by 40% the maximum amplitude of the radial vapor force (808) applied to the mobile spiral (3). In addition, this reduction results in a decrease in the variation in sealing force between the movable spiral (3) and the fixed spiral (2) and allows better control of the tightness on the sides while improving the fatigue resistance of the materials. .

FIG. 18 also shows that the presence of the cavities (303 and 406) as well as notches (312) make it possible to increase the average tangential force of steam (808) applied to the movable spiral (3). This increase results in an increase in the torque delivered by the expansion machine (804) implying a yield gain of up to 2% depending on the pressure ratios applied to the inlet and outlet of the machine.

The fixed and mobile spirals (2 and 3) both have a nose leave (410 and 309) at the foot of the central end of the spiral profile (usually called the "nose" of the spiral). These leaves (410 and 309), whose radius is typically between 0.2 millimeter and 0.5 millimeter, are intended to reduce the stress concentration present on the nose, this place generally being the one for which the stresses are the most strong. Although it is known that the performance of a volumetric expansion machine can be improved by means of a thin nose profile, the profile of the base of the nose has been enlarged in order to reduce the stresses to an acceptable level. In the example described, the stress level was calculated around 100 MPa, which is acceptable in service life for cast iron spirals. Alternatively, it is known that steel spirals can have a thinner nose, and therefore have better performance. However, this type of solution increases the production cost of the machine.

The fixed and mobile spirals (2 and 3) both have a chamfer (421 and 318) in their central zone, at the top of their noses. These chamfers are intended to avoid any interference with the fillets of the nose (410 and 309) of the opposite spiral during the movement of the mobile spiral (3).

The fixed spiral (2) has a cavity (409) located in the central zone, extending axially from an intermediate plane (2003) to the front surface opposite the transverse disc end plate (2001) at level of his nose. The movable spiral (3) also has a cavity (313) located in the central zone, extending axially from an intermediate plane (3003) to the front surface opposite the transverse disc end plate (3001) at the level of his nose. As described in more detail below, these cavities (409 and 313) are used to ensure that the two symmetrical chambers are subjected to the same vapor pressure. FIG. 14 presents sectional views of the central zone of the fixed spiral (2) and mobile spiral (3) assembly over the three different stages (604, 606 and 607) of the machine's expansion cycle (804). These sectional views are presented according to three different levels "H1" "H2" and "H3", "H1" being located at the bottom of the fixed spiral (2002) and at the top of the movable spiral (3002), "H2" being located in the middle of the two spirals (2002 and 3002) and "H3" being located at the top of the fixed spiral (2002) and at the bottom of the movable spiral (3002). In steps 606 and 607, without considering the cavities (views "H2"), the steam chamber (420) in contact with the intake port (407) will be supplied with steam (808) more than its symmetrical chamber (419 ). Consequently, the pressure of the first chamber (420) will be greater than that of its symmetrical chamber (419) during expansion. In order to limit this phenomenon, the cavity (313) of the movable spiral (3) makes it possible to open a communication channel (319) between the two symmetrical chambers (419 and 420). The cavity (409) of the fixed spiral (2) also makes it possible to open a communication channel (315) between the two symmetrical chambers (419 and 420). These two channels (314 and 315) make it possible to reduce the pressure difference between the two symmetrical chambers (419 and 420).

The two symmetrical chambers (419 and 420) are ideally subjected to the same vapor pressure, because it is known that a pressure difference in the two symmetrical chambers (419 and 420) causes instability of the machine (804) during its operation , which increases noise and vibration levels during operation, and tends to shorten its overall life.

These cavities (409 and 313) are located axially from intermediate planes respectively (2003, 3003) to frontal surfaces opposite the transverse disc end plates respectively (2001, 3001) at the noses of their spiral respective so as not to reduce the size of the nose near the nose leaves (410 and 309), in order to guarantee the mechanical strength of the spiral noses. The oblong hole (407) of the fixed spiral (2) is also located at a distance from the fillet (410) in order to avoid any concentration of stress detrimental to the mechanical strength of the fixed spiral (2).

The central bore (407) of the fixed spiral has an oblong shape. This shape, its precise positioning (angle, center) and the fact that this drilling takes place partially in the material of the fixed spiral (2) have been determined in such a way as to optimize the flow of steam at the inlet while maximizing the ratio of volume of the trigger. It is known that the ideal form of this piercing is a form of "bean" (426) of the type of that presented in FIG. 16, however this type of form proves difficult to machine on an industrial scale. A simple round drilling is easier to perform, but also has poorer performance: lower inlet flow and / or lower volume ratio.

The movable spiral (3) has, around its surface in contact with the stop, a small angle chamfer (310), typically between 1 degree and 5 degrees, visible in the detail view D of FIG. 4. This chamfer (310) is intended to create a hydrodynamic effect beneficial for the lubrication of the sliding contact between the movable spiral (3) and a washer (9) of the axial stop. The transition between a rear face (317) of the movable spiral (3) and the chamfer (310) is carried out by virtue of a connection leave (316).

In the example described, the fixed (2) and mobile (3) spirals are made of cast iron, in particular a spheroidal graphite type cast iron resistant to ethanol.

The parts are produced by foundry in a mold and by machining the spiral profiles and the various holes, then can be the subject of a surface treatment by nitriding in a salt bath followed by an oxidation phase or alternatively a manganese phosphate phosphating treatment.

Alternatively, the parts are made of steel which may or may not be subject to a DLC type treatment on at least its contact surface at the level of the spirals.

Detailed description of the moving part

Figures 3 and 6 respectively show a longitudinal sectional view of the machine and a perspective view of the elements constituting the movable part of the expansion machine.

The anti-rotation ring (12) surrounds the movable spiral (3). It is positioned so that the axial force induced by the pressure in the movable spiral (3) is transmitted directly to the support of the axial stop (220). This ring is called "female - female" because it has grooves arranged perpendicular to each other. This configuration allows the ring to bring the two forces applied to it axially, namely the force applied by the studs (302) of the movable spiral (3) and the reaction force applied by the studs (403) of the fixed spiral (2). The fact that these two forces are axially close has the effect of minimizing buckling of the ring (12) under load.

The movable spiral (3) has the central hub (320) in which is housed a bearing (106).

This hub contains an insulation cup (11). This cup (11) makes it possible to create a volume of static vapor forming thermal insulation at the place where the temperature of the movable spiral (3) is the highest. The cup (11) has holes intended to prevent the accumulation of liquid in the volume of insulation.

It is known that the sealing force in volumetric machines with spirals whose radial guidance of the movable spiral is said to be accommodating (“compiling” in English) is obtained with the inertia of the movable spiral and / or by shifting the axis of the eccentric crank pin (314) so that the reaction of the tangential vapor force (808) of the mobile spiral (3) on the eccentric crank pin (314) induces a force resulting in the radial direction of the mobile spiral (3). This radial force induced in the plane of the sealing points (416) makes it possible to artificially increase the sealing force of the fixed and mobile spirals (2 and 3).

In the particular case of the expansion machine (804) according to the invention, the inertial contribution of the movable spiral (3) to the sealing force is eliminated by means of dynamic balancing carried out with the counterweight (14 ). This feature makes it possible to make the sealing force independent of the speed of rotation of the expansion machine (804). This feature is particularly essential when the expansion machine (804) is connected to an associated rotary machine (801) whose speed of rotation is variable. Thus, the sealing at the sides between the movable and fixed spirals (2 and 3) at low speed is improved, and the risk of damage to the spirals at high speed is reduced.

The connection between the shaft (13) and the counterweight (14) is carried out by means of the crown (26), visible in FIG. 15. The crown (26) is fixed on the shaft (13) by the screw intermediate (27) and can alternatively be shrunk in its housing. The convex shape (26) has a slightly convex fitted surface (260) at the level of the contact surface with the counterweight (14). This convex surface (260) has a radius of curvature of the order of one meter and allows the counterweight (14) to have a rectilinear linear connection with the shaft (13). The contact line between the bulge (26) and the counterweight (14) makes it possible to reduce the hyperstatism of the expansion machine (804) and thus to eliminate the transmission of the moment generated by the axial forces of steam (808) to the 'tree (13). The dimensions of the crown (26) may also be adapted in order to modify the effective offset of the eccentric crank pin (314) with respect to the shaft (13), and therefore to modify the sealing force between the two spirals ( 2 and 3). The domed (26) may advantageously be produced by an insert to facilitate its production, in particular when this part will require a hardness and / or a surface condition that is more restrictive than those of the shaft (13). It will thus be possible to economically assemble a bent (26) of rectified treated steel with a shaft (13) of cast iron or steel directly obtained from turning or milling.

Detailed description of the housing assembly

Figures 3 and 7 respectively show a longitudinal sectional view of the machine, a perspective view of the elements constituting the housing assembly in partial section. Figures 9 and 19 respectively represent variants in the contact surface of the washer (9) and a variant of the washer (9) having an annular back pressure chamber.

This assembly (200) consists of two main parts: the casing (5) and the PTO adapter (8) (PTO is the abbreviation of the English term "Power Take-Off", equivalent to the French "Prize de Power Auxiliaire" ). These two parts are assembled using a bolted assembly which also allows the casing assembly (200) to be mounted on the spiral cover (4).

The sealing and centering of the casing assembly (200) with the spiral cover are ensured by a cylindrical flange (201) and by the O-ring (74) disposed in an annular groove (229). It is a low-pressure zone at low temperature relative to the rest of the machine, which allows the use of inexpensive elastomer seals, rather than seals resistant to high temperatures. The seal (74), like all the other static seals of the machine, is an O-ring made of fluoroelastomer, for example VITON (trade name) or EPDM (ethylene-propylene-diene monomer).

The sealing and centering of the casing part (5) with the PTO adapter part (8) is ensured by a cylindrical centering (217) and by an O-ring (72) arranged in an annular groove (228).

In the example described, the PTO adapter part (8) has fixing means (205) allowing the mounting of the expansion machine (804) on the associated rotary machine (801), for example at a level outlet. force and in particular the rear power take-off, provided on the associated rotary machine (801).

The geometry of this fixing means can be adapted as a function of the interface available on the casing of the associated rotary machine (801). In the example described, this fixing is carried out by bolting using ears (205). The seal is ensured by an O-ring (75) disposed in an annular groove (221).

The positioning of this fixing means (205) and the compactness of this part allow the machine to be partially inside the casing of the associated rotary machine (801), thus reducing the visible external bulk of the machine ( 804).

The housing assembly (200) has one or more adjusting shims (23) taking the form of a housing flange (417). The thickness of this shim is adjusted in order to adjust the axial clearance between the fixed spiral (2) and the movable spiral (3),

in order to reach a game nominal, by example 50 microns. This nominal axial clearance between 1 es spirales ( 2 and 3) East calculated in function in particular of temperatures and pressures of applied operation machine (804), but also from the joint stiffness high temperature dish (6). The mastery of this axial clearance is all the more essential than the machine (804) is planned for function in high temperature (up to 250 ° C).

This housing assembly (200) comprises an axial stop support (220) taking up the axial forces generated by the vapor pressure on the movable spiral (3). The friction exerted on this stop during the movement of the movable spiral strongly affecting the overall performance of the machine (804), a surface treatment is applied on one of the surfaces of the stop, on the side of the movable spiral (3 ) or the housing (5), or both, to reduce friction losses due to this contact. In the example described, this treatment was not carried out directly on the parts, but on a steel washer coated with a MétalPolymère composite (9) (for example supplied by the company Daido Métal, trade name DAIDYNE DDK05) or any other similar surface coating produced in particular by a layer of PTFE (polytetrafluoroethylene) or any other material of Young's modulus less than or equal to 5 GPa, with a minimum thickness of 50 μm deposited on a metal substrate allowing the mechanical attachment of the flexible material (PTFE or other) and heat dissipation. The attached washer (9) was fixed on the stop support (220) in order to reduce friction with the movable spiral (3). Alternatively, it may be fixed on the movable spiral (3), or may not be fixed at all. The washer (9) makes it possible to greatly simplify the process of carrying out the surface treatment, this being difficult and costly to carry out on bulky parts. In the example described, the washer (9) has been fixed using rivets (105), but could be fixed by any other means (screws or pins for example) without this modifying its principle of use. Alternatively, the washer can be centered on its inside or outside diameter and stopped in rotation by a lug or a pin.

The use of a washer (9) comprising a thickness of flexible material (Young's modulus less than 5 GPa) and a thickness of the order of 50 to 250 microns allows accommodation of the surface and facilitates the formation of an "oil wedge" on the inner edge of the surface (211). The layer of flexible material also allows a certain accommodation over the whole of its flat surface, it can advantageously be used rough, without requiring any rework or rectification which would have been necessary to reach an acceptable level of flatness if the part had been made of metal or coated with a thin deposit.

According to examples of variants presented in figure 9, and in sight improve the performance of the machine, the washer ( 9) stop can behave on his face prone rubbing many areas in depression ( 222) spread substantially homogeneous. according to a

alternatively, these depressed areas - or pockets - (222) are substantially circular and have a shallow depth compared to their diameter, typically 30 to 100 μm in depth. The pockets (222) preferably have a radius less than the eccentricity of the orbital path of the movable spiral (3) which promotes the renewal of the oil in the cavity and on the opposite face thanks to the kinematics of the spiral mobile (3). The minimum distance between neighboring pockets (222) may be substantially less than or equal to an orbit diameter, and chosen to ensure a ratio (pocket surface / abutment surface) of between 20% and 50%.

Of way preferential, pockets (222) are conducted sure the face of the stop fitted washer (9) reported in polymer, and their depth is lower or

equal to the thickness of the polymer layer, which makes their production more economical and above all ensures a connection between pockets and non-aggressive flat part for the opposing part.

The pockets (222) can be connected together by communication channels (214) of small width in order to favor the renewal of the oil which they trap, and thus to avoid the heating of the interface, in particular on machines having to operate at high speed of rotation and / or having an axial stop extended radially (for example when the stop width is greater than six times the eccentricity of the orbital movement of the movable spiral).

The channels (214) connecting the adjacent pockets will be arranged to allow, step by step, oil circulation between the inside diameter and the outside diameter of the thrust washer (9); advantageously the channels (214) will be arranged in the tangential direction, in the favorable direction with respect to the movement of the movable spiral (3). Said tangential direction is oriented so that the channels (214) are perpendicular to the direction of instantaneous movement of the movable spiral (3) at the place where the axial stop is the most loaded. Said channel orientation (214) and the direction of movement of the movable spiral (3) are indicated in FIG. 9.

These communication channels (214) ending in the pockets (222) can be produced on one side or the other of the washer (9) without this modifying their principle. Finally the channels (214) will have a small passage section in front of the cross section of a pocket (222) so as not to penalize their lift.

Radial ridges (212) may also be produced on the surface of the axial thrust washer (9), in order to facilitate the supply of oil to the contact and reduce the power dissipated by shearing of the oil film. The depth of these streaks is comparable to the pockets presented above (222). The number of streaks, their orientation and their width can be adapted according to various parameters, such as the type of fluid used or the type of oil used.

An annular groove (223) can be arranged on the active face of the metal-polymer washer (9), in the thickness of the polymer, defining one or more annular chambers (223) between the rear face of the movable spiral (3) and the thrust washer (9) as shown in FIG. 19. This annular chamber (223) is supplied with working fluid (808) at higher pressure than the ambient pressure of the thrust by one or more openings (225) in the bottom of the movable spiral (3), and thus applies a selected pressure - by the position of the hole - in order to compensate for part of the axial force to which the movable spiral (3) is subjected due to the pressure distribution in the spirals (2 and 3).

This pocket (223) is dynamically sealed on its edges (226) thanks to the capacity of accommodation of the polymer, the sealing being further improved by the presence of the oil in the working fluid (808). The tightness obtained is all the more effective the greater the axial pressure force, due to a more pronounced crushing of the polymer. The assembly achieves a reduction in the net axial force passing between the movable spiral (3) and the abutment support (220) via the polymer abutment washer (9), with a view to reducing the local heat dissipation and improve the performance of the machine (804).

The metal-polymer washer (9) can be installed on the fixed support (220), in this case the chamber (223) has at least locally an extension (224) of dimension substantially close to the orbit diameter, in order to be continuously supplied by the bore (225) arranged in the movable spiral (3). Advantageously, several bores (225) in the mobile scroll can supply several extensions (224), allowing said extensions to have a more limited dimension, in particular less than an orbit diameter, without interrupting the pressure supply to the room (223).

Due to its location in the fixed support, the washer (9) will be subjected to a lower temperature and will be cooled by conduction to the fixed support (220).

Alternatively, the metal-polymer washer (9) can be installed at the rear of the movable spiral (3), the annular chamber can thus have a limited and constant radial extent, which is favorable with regard to the length of the leak path between the chamber (223) and the pressure of the surrounding chamber (817).

On the casing side (5), the axial stop support (220) is produced on an annular crown in the shape of a tee (210). The diameter of this tee (210) as well as its thickness has been calculated so that the bending of the stop support (220) in the axial direction conforms to the bending of the movable spiral (3) when the spirals (2 and 3) are under pressure. This allows the contact pressure on the thrust washer (9)

to stay homoi gene and avoid all peak of constraint on her circumference interior (in the case or said crown ring finger is too rigid) or outer (in the case or said spiral In is too rigid). the example described , the area washer of

axial stop (9) is planar, in order to minimize contact pressures. The inner edge of this surface (211), as well as the edges of the abutment surface on the movable spiral side (3), visible in FIG. 4, have a chamfer (310) with a very small angle, typically between 1 degree and 5 degrees. This chamfer allows the oil to be distributed over the surface, and creates a hydrodynamic effect beneficial for the lubrication of the contact between movable spiral (3) and axial thrust washer (9). The transition from the back

(317) plane of the stop and this chamfer (310) spiral side mobile (3) is carried out grace to a leave of connection (316). The bottom of the housing (5 ) presented by elsewhere a exit central tree whose the inner tubular surface

is machined to receive the bearing (103), the shaft end seal (71) and possibly the second shaft end seal (70).

An annular space (202) between the shaft end seals (70, 71) constitutes an air chamber (202) making it possible to avoid contamination by the working fluid contained in the associated rotary machine ( 801) on which the expansion machine (804) is mounted.

This chamber (202) is pierced by a vent (203) opening to the outside, in the lower part of said annular chamber (202), when the machine is mounted on a motor, to allow the evacuation of possible leaks from fluids (working fluid (808), or possibly fluid present in the associated rotary machine (801).

The seals (70, 71) are annular lip seals, the lips being oriented in directions opposite to the chamber (202) to promote the sealing of the machine (804) relative to the working fluid (808) of a on the other hand and the tightness with respect to the fluids present in the associated rotary machine (801). Thus, the chamber (202) forms a volume for recovering the fluids in order to evacuate them to the outside, and to avoid any contamination between the two machines (804 and 801). These lip seals could be replaced by any other dynamic sealing device (mechanical seal seals for example) without this modifying the principle of the invention.

In the example described, the seal (71) is made of polytetrafluoroethylene (PTFE), for example a lip seal sold under the reference BEKA 804 or BEKA 806 by the company FranceJoint (trade names).

Detailed description of the coupling assembly on an associated rotary machine

Figures 3, 8 and 11 respectively show a longitudinal sectional view of the machine, a perspective view of the elements constituting the coupling assembly in partial section and a schematic view of a Rankine cycle according to the invention .

A Rankine cycle recovers waste heat from an associated rotary machine (801), which can be an internal combustion engine or an electric machine. This heat can be recovered in several places: on the cooling circuit, on the cooling of the compressed air upstream of the engine, on the cooling of the exhaust gases recirculated in the rotary machine or on exhaust gases (802 ) as shown in Figure 11.

In the latter case, a heat exchanger (807) is inserted in bypass on the exhaust line after the pollution control system (803). A bypass valve (827) distributes the flows proportionally between the heat exchanger (807) and the normal exhaust.

The exchanger (807) is an evaporator intended to evaporate the working fluid (808) of the Rankine cycle. The working fluid (808) is sucked by the pump (806) from an expansion tank (828) at pressure controlled by an electric valve (829). The proportional electric valve (829) regulates the air pressure in the expansion tank (828) either by connecting the expansion tank to a source of compressed air (821), or by connecting the expansion tank ( 828) to the atmosphere.

The temperature and pressure of the working fluid (808) upstream of the pump (806) as well as downstream of the evaporator (807) are measured by sensors. The Rankine cycle computer receives these signals to control the actuators of the system as well as a vapor temperature in the expansion machine (804) measured either in the expansion zone (816) or in the exhaust zone ( 817).

The steam produced in the evaporator (807) flows to the expansion machine (804). The expansion machine (804) comprises three zones: an admission zone (814) for the high pressure steam which is connected to the expansion zone (816), itself connected to the exhaust zone (817 ) at low pressure. The bypass valve (59) opens and closes a bypass channel connecting the intake area (814) and the exhaust area (817). The bypass valve (59) is advantageously pneumatic and is connected to the source of compressed air (821). An electric valve (820) controls the admission of air into the bypass valve (59) either by connecting the bypass valve to the source of compressed air (821), or by connecting the bypass valve (59) to the atmosphere. The bypass channel or the bypass valve (59) further comprises a restriction, typically of the order of 20 mm 2 in order to limit the volume flow through the bypass channel and cause a pressure rise in the zone upstream of the restriction.

Low pressure steam escaping from the expansion machine (804) from the exhaust zone (817) flows through the condenser (805) to return to the liquid state. The condenser (805) is cooled either by a fluid from the associated rotary machine (801) or by ambient air. For example, one or more of the cooling circuits of the associated rotary machine (801) can be used. The condensed working fluid then returns to the expansion tank (828).

A coupling zone (99), made up in particular of the coupling assembly (500) and the rear bearing (104), is isolated from the working fluid (808) via the end gasket (71). 'tree. This particular arrangement allows the elements located in the coupling zone (99) to have a means of lubrication independent of the lubrication system of the volumetric machine (804). This arrangement also makes it possible to limit the area containing the working fluid (808) and guarantees maximum compactness of the machine (804).

The expansion machine (804) is connected to a rotating shaft (813) of the associated rotary machine (801). The coupling assembly (500) enables the connection between the shaft (13) of the expansion machine (804) and the shaft (813) of the associated rotary machine (801).

The coupling assembly (500) is not limited to the example presented and may consist of other coupling means, for example a combination of the following elements: freewheel, clutch of any type, shock absorber of vibration, gear, pulley, belt.

This assembly (500) is located in the PTO adapter (8), but is isolated from ethanol vapor by the shaft end seal (71). The positioning inside the casing of the associated rotary machine (801) allows this assembly to benefit from a means of lubrication independent of the working fluid (808).

This assembly (500) is to be adapted as a function of the associated rotary machine (801) on which the machine (804) is mounted. The geometry of the toothed wheel (10), in particular, must be modified according to the machine (801) used.

This assembly (500) consists in particular of a toothed wheel (10), arranged around the central shaft (13), making it possible to transmit the mechanical power generated by the machine (804) to the associated rotary machine (801). The speed ratio between the machine (804) and the associated machine (801) is fixed and is typically between 1 and 6.

This assembly (500) consists in particular of a freewheel (30). In the example described, the freewheel (30) is with cams, but it can equally be designed according to another technology (freewheel with rollers for example). This freewheel is, in the example described, implemented between the shaft (13) and the interior of the toothed wheel (10). This freewheel (30) acts as a clutch for the machine (804). In fact, when the vapor pressure is not sufficient to drive the rotation of the shaft (13), the freewheel allows the associated rotary machine (801) to turn without driving the machine (804) (freewheel bandwidth).

When the vapor pressure is sufficient to cause the rotation of the shaft (13), the power of the machine (804) is supplied to the associated rotary machine (801) and the speed of rotation of the machine (804) is limited by that of the associated rotary machine (801) (free wheel in engagement).

This assembly (500) consists in particular of one or more bearings (31 and 32), making it possible to take up the axial and radial forces induced by the toothed wheel (10).

Detailed description of lubrication

Figures 3, 6, 10 and 15 respectively show a longitudinal sectional view of the machine, a view of the partially cut moving part, a longitudinal sectional view of the machine with arrows indicating the direction of the oil flows as well as '' a view of the rotating parts of the machine

In the example described, the expansion machine (804) uses at least two sources of lubrication. The first source of lubrication comes from the oil contained in the working fluid in the form of vapor, this oil being able to be used in particular to lubricate the contacts of the anti-rotation ring (12), the axial thrust washer (9), the seal. shaft end (71), the crown (26) and the bearings (103 and 106). A part of the machine being mounted directly inside the casing of the associated rotary machine (801), the elements located in the coupling zone (99) have an independent lubrication means, which can come from the oil used in the housing of the associated rotary machine (801). In this case, the oil flows associated with these two lubrication sources are represented by black arrows in FIG. 10 for the oil flow coming from the working fluid (808), and by gray and black arrows for the oil flow from the casing of the associated rotary machine (801).

Alternatively, the elements located in the coupling zone (99) can also have a means of lubrication independent of the associated rotary machine (804), for example by permanent lubrication.

The working fluid in the form of vapor (808) at the outlet of the spiral is loaded with oil and circulates with a rotary component. This circulation leads to a centrifugal force tending to entrain the oil particles towards the interior wall of the spiral cover (4). The slide connections of the anti-rotation ring (12) and part of the axial stop (220) are supplied with oil by this direct flow.

The oil is then captured by the inclined holes (402), then passes via inclined holes in the casing (204) to the annular volume (207), allowing the oil to lubricate the shaft end seal (71 ) as well as the bearing (103).

The rotation of the counterweight (14) causing a depression in the corresponding annular volume (208), part of the working fluid (808) charged with oil then passes through the bearing (103) to reach said volume (208) and to be captured. by the counterweight (14).

When the working fluid (808) loaded with oil

find in volume interior ( 141) of counterweight it East animated a movement of rotation who spray oil, more heavy than the fluid of job, against walls (142 ) of said counterweight (14) through centrifugati we. Oil adheres to the

walls (142) by capillarity and is then driven by the rotational movement of the counterweight (14) in cavities (140). These cavities have a tangential ramp (143) to facilitate entry as well as a wedge (144) allowing the oil to accumulate in the cavities (140). The progressive filling of the cavities (140) pushes the oil axially until it is projected onto the rear face (317) of the movable spiral (3). The counterweight acts as an oil separator from the working fluid (808) which is then evacuated from the interior volume (141) of the counterweight to the volume (208) and then by radial bores (209).

The other part of the flow of the working fluid loaded with oil from the volume (207) is directed towards the inside of the counterweight via axial grooves (307), visible in FIGS. 5 and 6. This flow makes it possible to lubricate the convex (26), and opens into the disc volume between the shaft (13) and the isolation cup (11). This flow then passes through the bearing (106) of the movable spiral (3) to open into the interior volume (141) of the counterweight where the oil is then projected against the rear face of the movable spiral (317) as described in the previous paragraph.

The oil sprayed against the rear face of the axial stop (220) is then entrained by the orbital movement of the movable spiral (3) in the connection with the washer (9).

The shaft end bearing (104) as well as the elements constituting the coupling assembly (500) are implemented in the coupling zone (99), which can be implemented inside the casing of the machine associated rotary (801). The means of lubrication of the elements of this zone (99) being independent of the working fluid (808), they can therefore be lubricated by the oil mist present in the casing of the rotary machine (801), the flow being moreover forced by rotation of the toothed wheel (10). Alternatively, the elements of said zone (99) can be lubricated by permanent lubrication.

Claims (10)

claims 1 - Volumetric spiral machine comprising: a first fixed structure (2) formed by a first transverse disc end plate (2001), one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a first spiral (2002), said end plate ( 2001) having a first central orifice (407) a second mobile structure (3) formed by a second transverse disc end plate (3001) one of the surfaces of which forms a bottom of a spiral, surmounted by a wall defining a second spiral (3002), said second structure (3) moving relative to said first structure (2) in an orbital motion, said spiral elements (2002, 3002) adjusting each other with an orbital offset to achieve a plurality of lines contact defining at least one pair of closed fluid chambers (411, 419, 420, 423, 424), the volume of said fluid chambers varying as a function of the relative position of one of said structs ures (3) relative to the other structure (2), an inner end of said spiral element (2002, 3002) having an upper indentation (respectively 409, 313) extending from the surface opposite to the plate (2001, 3001) up to an intermediate section (2003, 3003) characterized in that the thickness of the wall of each of said spirals (2002, 3002) varies between a constant nominal thickness on an intermediate part extending over more than one turn, and a reduced thickness, at the level of said upper indentations (409, 313), in a central extremal part extending between 60 ° and 120 ° from the inner initiation of the spiral, said reduced thickness being less than 50% of said nominal thickness. 2 - Volumetric spiral machine according to claim 1 characterized in that the central orifice (407) of said first end plate (2001) has an oblong shape, one of the ends of said central orifice (407) of oblong shape intersecting the transverse projection of the non-indented intermediate zone (2004, 3004) of the spiral (2002, 3002), the extreme zone (2005) of the spiral (2002) surmounting said first end plate (2001) having a lower indentation (2006) extending from the periphery of said end of the oblong orifice (407) to the median zone (2004) not indented with the spiral (2001). 3 - Volumetric spiral machine according to claim 1 characterized in that at least one of said transverse disc end plates (2001, 3001) has in a peripheral annular zone a plurality of cavities separated (303, 406) by bridges (425) and hollowed out relative to the spiral bottoms of said disc end plates (2001, 3001). 4 - Volumetric spiral machine according to the preceding claim characterized in that the inner edges (450) of said cavities (303, 406) are located on a line (451) offset radially by less than 60% of the thickness of the wall of the spiral (2002, 3002) to the projection of the internal surface of the peripheral end of the opposite spiral (2002 3002), when the peripheral chamber formed between the two spirals opens out (step 601). 5 - Volumetric spiral machine according to claim 3 or 4 characterized in that the width of said cavities (303, 406) measured in the radial direction is greater than the thickness of the wall of the opposite spiral (2002, 3002). 6 - Volumetric spiral machine according to claim 3 or 4 characterized in that the depth of said cavities (303, 406) is greater than 0.5 millimeters. 7 - Volumetric spiral machine according to claim 1 characterized in that the upper front surface of at least one of said spirals (2002, 2003) has a central groove (308, 408) for positioning a seal (17, 18). 8 - Volumetric spiral machine according to the preceding claim characterized in that the upper front surface of at least one of said spirals (2002, 3002) has, on the internal edge, notches (312) opening into said median groove ( 308, 408). 9 - Volumetric spiral machine according to claim 3 or 4, and the preceding claim characterized in that said notches (312) of the spiral (2002, 3002) of one of said structures (2, 3) are positioned to communicate, during the orbital movement, with the cavities (303, 406) formed in the disc end plate (2001, 3001) of the complementary structure (2, 3). 10 - Volumetric spiral machine according to claim 1 characterized in that the fixed and mobile spirals (2002, 3002) both have a leave (410 and 309) at the foot of the central end of the spiral profile 5 and a chamfer (421 and 314) on the inner edge of the spiral top in their central area.