WO1997003327A1 - Refrigerator or heat pump with a pulse tube operated by a pressure generator - Google Patents

Abstract

A refrigerating machine consisting of a variable-volume pressure generating chamber (30) for generating pressure waves in a pulse tube (55) via a thermal regenerator (53). Heat is extracted from a cold source (57) and delivered to a hot source (58) to provide correct adjustment of the apparatus. The variation in the volume of the chamber (30) is caused by the circular translation of a moving part (32), thus avoiding the wear and lubrication problems typical of pistons commonly used for the same purpose. The moving part (32) and a facing stationary part (31) may have walls with an arcuate, sinusoidal or spiral cross-section.

Description

 REFRIGERATOR OR HEAT PUMP WITH PULSATION TUBE SUPPLIED BY A PRESSURE GENERATOR

DESCRIPTION The invention relates to a refrigerator or heat pump machine with a pulsation tube supplied by a pressure generator driven by a circular translational movement.

Depending on the field of application considered or the temperature range concerned, the vocabulary used to describe certain machines can take different forms.

This is particularly true for thermal machines whose role is to transport thermal energy (heat) from a lower temperature level (cold source) to a higher temperature level (hot source), making gain the energy transferred in quality.

The machine which realizes any transfer of thermal energy and therefore values the heat transferred is subject to the general principles of thermodynamics according to which the transformation considered consumes clean energy which can be communicated to it in any form, most often mechanical, thermal or electromagnetic.

When the machine considered essential aim of removing the ^heat with a cold source, there is a refrigerator, whatever the temperature level considered. When the cold source is between a few Kelvin and around 100 Kelvin, we speak of a cryogenic refrigerator. When the temperature of the cold source is 200 to 250 Kelvin (-70 ° C to -20 ° C approximately) and especially if the installation is large, we speak of refrigeration machine or industrial refrigerator. For temperatures close to 0 ° C or slightly lower, we commonly speak of a household or domestic refrigerator. Finally, if the cold source must be kept between 10 and 20 ° C in order to stay at a pleasant level, the machine is called an air conditioner.

If, on the contrary, the aim sought is the supply of heat to the hot source, the machine is called a heat pump.

However, the same principles or the same procedures can always be used for these devices. The most commonly used methods use fluids chosen according to the temperature levels considered and which are subjected to operations intended to vary their temperature or their entropy. For industrial or domestic refrigeration applications, the fluids generally used belong to the family of chlorofluorocarbons (CFCs) and they are used in the range of temperatures where they can exist in the state of saturated fluid. Frequently the reverse Rankine cycle is used, represented in FIG. 1 and which consists of compression of the gas phase on the line AB, expansion of the liquid phase on the line CD, condensation of the compressed gas on line BC and evaporation of the liquid on line DA. It is a classic diagram of entropy on the abscissa and temperature on the ordinate. Curve E traces the limit of change of state between the liquid and vapor phases (start and end of vaporization). Heat is released when the gas condenses and is absorbed when the liquid evaporates. The refrigerant is in heat exchange relationship with the hot source in the first case and with the cold source in the second case. For cryogenic applications, gas cycles are mainly used which successively include compression, cooling, expansion and heating. As indicated in FIG. 2, the compression, associated with the generation of heat, is carried out at the hot source in accordance with the line FG, for a diagram of the same nature as that of the preceding figure. The expansion, which is accompanied by heat absorption, takes place at the cold source in accordance with the line HI. The cooling operations along the GH lines and the heating along the IF line (isobars or isochores) allow the fluid to pass from one temperature level to the other in the most reversible way possible, that is to say ie by transferring the heat to one or the other of the GH and IF lines with the smallest possible temperature differences.

In continuous circulation cycles, these operations are carried out in counter-current heat exchangers. This is for example the case in the cryogenic cycles of Claude or Brayton using helium, hydrogen or nitrogen as gas depending on the target temperature.

In cycles with alternating circulation, the gas exchanges heat with a thermal accumulator or a thermal regenerator which retains the heat when the gas circulates in one direction and releases it when returning in the opposite direction.

The best known alternating circulation cycles are those of Stirling, Vuilleumier, Gifford and Mac Mahon as well as the pulsation tube cycle, for which a more complete although schematic description of corresponding devices is given in the following figures 3 to 5 . In FIG. 3 representing a Stirling machine, the compressor 1 or pressure oscillator is made of a mechanically actuated piston.

In FIG. 4, which represents a machine according to the Vuilleumier cycle, a thermal compressor

2 is used. A piston 3, called a displacer because the pressures on its opposite faces are always equal to each other except for the pressure drops, moves in a tube 4 of the thermal compressor 2 in an alternating movement between a hot source at temperature Tl and a source at intermediate temperature T2. Gas is expelled from the compressed source in favor of that which expands with each movement of the piston 3 passing through the clearance around the piston 3 or in a thermal regenerator lβ, and it changes temperature in contact with the other source , and therefore pressure and volume, which affects the rest of the device, namely the refrigeration machine.

In FIG. 5, the Gifford and Mac Mahon machine is characterized by a gas compressor 5 with a low pressure inlet 6 and a high pressure outlet 7, permanent and connected to the refrigeration machine proper 10 by a valve 'Entrance

3 and an outlet valve 9 respectively, which are opened in turn to generate the necessary pressure cycles.

The refrigerating machine 10 which is connected to these compressors 1, 2 and 5 is the same in the three figures. It consists of a tube 11 in which slides a displacement piston 12 which divides the contents of the tube 11 into two chambers with variable volume, connected to each other by a bypass 13 on which a thermal regenerator 14 is installed. The chamber connected to compressor 1, 2 or 5 is at temperature T2 (corresponding to the hot source for Figures 3 and 5 and at the intermediate temperature source for FIG. 4: the Vuilleumier cycle in fact involves three temperature levels), and the other chamber is at the temperature T3 of the cold source. The displacer piston 12 passes the compressed gas from the chamber at temperature T2 to the chamber at temperature T3 by exchanging its heat with the thermal regenerator 14 in response to the pressure increases in the compressor. The expansion of the gas is produced when it mainly occupies the chamber at temperature T3, then the gas is reheated by passing through the thermal regenerator 14 towards the chamber at temperature T2 before undergoing a new cycle. The thermal regenerator 14 has the property of restoring to the gas flowing therein in one direction the heat which it previously took from the gas flowing in the opposite direction. In the embodiment of FIG. 5, the temperature chamber T2 communicates with the compressor 5 by the inlet 6 and the outlet 7 as, as we have seen; in the embodiments of FIGS. 3 and 4, the connection of the compressor 1 to the chamber of the compressor 2 at the temperature T2 is carried out by a single pressure tapping pipe 15.

From the illustration in FIG. 3, it can be seen that the machines thus alternative are the seat of two periodic waves in the expansion volume 17, one of pressure and the other of flow. It is possible to control the phase shift of these two waves by mechanical means which control the movements of the compressor piston 1, 2 or 5, generally at room temperature, and of the displacing piston 12 which may, for cryogenic applications, have to function at very low temperatures. We then actually arrive at the desired situation where the maximum relaxation, that is to say say the maximum heat absorption, is simultaneous with the maximum gas flow in the cold source T3.

FIGS. 6A, 6B and 6C illustrate three variants of machines with a pulsation tube. Each includes a pressure oscillator 18, symbolized by a mechanical compressor, a thermal regenerator 19 connected to the compressor 18 by a pressure tapping duct 20 and a pulsation tube 21 which branches at the end of the thermal regenerator 19 opposite to the pressure oscillator 18. In FIG. 6A which illustrates a basic embodiment, the pulsation tube 21 is closed at the end opposite the thermal regenerator 19; in Figure 6B which may allow better results, it is extended by an orifice 22 which leads to a reservoir 23; and in FIG. 6C, which also includes an orifice 22 and a reservoir 23, an additional improvement exists in the form of a bypass 24 between the orifice 22 and the pressure tap conduit -20 in order to send the wave of pressure in the two ends of the pulsation tube 21. It is then usual for a valve to be placed on the bypass 24 to control the flow. By the combined effect of the different volumes and throttles, the phase shift necessary for the refrigerating effect of the flow and pressure waves is obtained by totally static means in the pulsation tube 21, which is therefore free or devoid of any moving object such as a displacement piston. More specifically, the pulsation tube 21 is throttled near the thermal regenerator 19, where the cold source SF is located, while the hot source SC is located at the opposite end of the pulsation tube 21, at the end of an enlarged portion of any shape, possibly cylindrical thereof, against the orifice 22 when it exists. The gas column is maintained oscillations, and the dimensions and the shape of the various elements of the apparatus make it possible to choose the operating frequency to obtain the phase shift of the flow and pressure waves which makes it possible to effectively extract heat from the cold source for transfer it to the hot spring.

These machines have with those which exploit a Rankine cycle the resemblance that they have only one moving part, at the place of the compressor, and therefore have the same simplicity of construction and the same reliability, but the absence of change of state allows the use of a neutral gas such as helium or nitrogen, or even air, instead of polluting chlorofluorocarbons.

It has indeed been experimentally verified that the pulsation tube machines 21, hitherto exclusively offered for cryogenic applications, were also able to operate up to around ambient temperature. However, they have never been applied industrially, even in cryogenics, because of their lack of thermal efficiency or because of the difficulty of producing sufficiently reliable pressure generators, despite numerous tests which are found in the prior art.

Soviet patent 4378 91 dating from 1974 describes a piston compressor associated with a pulsation tube which can be composed of two stages. US patent 3,817,044 of the same year describes a compressor for adsorption of hydrogen on lanthanum nitride. A thermo-acoustic compressor is proposed in the American patent 4 953 36δ; there is a piston, controlled by a heat source, in US Patent 4,584,840; finally, a gas jet whose mechanical energy is used is imagined as a pressure source in Soviet patent 10863 18.

The pressure wave can also be controlled by valve switching leading to two sources of unequal pressure, as in US Pat. No. 3,237,421; by a rotating distributor driven by a motor, as in French patent 1,444,558, which amounts to a materialization of the solution sketched in the previous patent; or by eccentric rotors rotating in a larger housing and on which pallets rub which delimit pressure generation chambers in the housing.

The essential improvements of the machine visible in particular in FIGS. 6B and 6C have the essential aim, in the known literature, of lowering the temperature of the cold source to very low levels, by a few tens of Kelvin. We will cite the articles by Zhu (ICEC 13, Péfcin 1990) and Ravex (ICEC 14, Kiev 1992).

It is mainly the means of producing the pressure wave which are envisaged in this invention, to make them well suited to this application of pulsation tube. Indeed, among the known solutions of], the piston systems must be lubricated to obtain a sufficient service life, which causes the risk of pollution by migration of oil or grease. Dry pistons experience significant friction and wear and therefore their maintenance-free operating time is limited. Thermal or thermo-acoustic solutions impose oscillation frequencies which must be made compatible with those sought in the pulsation tube, which can be difficult, and the heat losses are significant, which reduces the overall efficiency of the machine.

The same criticism of significant friction can be addressed to rotary systems with distributor or eccentric rotor.

The object of the invention is therefore to produce the pressure wave in a simpler manner and with less technological disadvantages, and the characteristic means, for this machine for transferring heat from a cold source to a hot source comprising as previously a pulsation tube, free and occupied by a column of gas and passing through the two sources, a pressure oscillator composed of a fixed portion and a movable portion delimiting a pressure generation chamber with variable volume communicating with the tube pulsation by a thermal regenerator, consists in that the movable portion is driven in circular translation by a motor and an eccentric transmission. It is also possible not to resort to pistons and to ensure the variation in volume of the chamber by means almost or entirely devoid of contact and friction. Friction is inevitable along the transmission or at its junction with the mobile part, but one generally has bearings, which produce only little losses and also have a long service life while providing good precision. In certain embodiments, these may be sealed or dry bearings, gas or magnetic. Even if the bearings are lubricated, the risks of contamination of the machine by the lubricant are low because the bearings are, unlike the compression pistons, far from it. Another advantage is that the gas pulse frequency can be controlled much more easily thanks to the speed of rotation or the frequency of oscillation of the mechanical crew. Finally, energy consumption is reduced, because the inertia or resonance effects of moving parts tend to equalize over a cycle. It is advantageous for the fixed and mobile portions to delimit the pressure generation chamber by curvilinear profiles at two points of tangency or quasi-tangency which approach each other during part of the circular translation, since the gas volume transferred is greater , and the waves more intense but less violent.

The transmission may simply consist of a drive shaft with an eccentric part connected to the movable portion by a bearing, or an eccentric surrounding the movable portion and, here again, connected to it by a bearing. The latter solution easily lends itself to a reduction or elimination of the overall inertia forces.

Devices - independent of the transmission can be provided to oppose the rotation of the mobile portion or to counter it. They may be bellows, springs, elastic elements in general or an additional rigid eccentric transmission. The invention will now be described in some of its embodiments with the aid of the following figures annexed by way of illustration and not limitation: FIGS. 1 and 2 describe certain thermodynamic cycles, FIGS. 3 to 5 illustrate certain machines with a displacement piston at the cold source, FIGS. 6A, 6B and 6C illustrate machines with a pulsation tube, Figures 7A to 7D illustrate the operating principle of the invention, Figure 8 illustrates a first embodiment of the invention, - Figures 9A and 9B illustrate two possible modifications for this embodiment, Figure 10 illustrates a second embodiment of l he invention, FIG. 11 illustrates a third embodiment of the invention, and FIGS. 12 and 13 represent two possible arrangements of compound machines.

The operating principle of the heat transfer machine according to the invention and in particular of its oscillation or pressure generation chamber will be described in connection with FIGS. 7A to 7D. The pressure generation chamber

30 is delimited by a fixed part 31 and a movable part 32 which have shapes, both substantially complementary and substantially identical: each comprises a rounded lobe (respectively 33 and 34) which penetrates into a rounded hollow (respectively 35 and 36) wider on the other of the pieces. The profile of each of the parts which is oriented towards the chamber 30 and which results from the juxtaposition of the lobe 33 or 34 with the rounded hollow 35 or 36 therefore has substantially the shape of a sinusoid. In FIG. 7A, the pressure generation chamber 30, composed of surface portions of the hollows

rounded 35 and 36 left free by lobes 33 and 34, is closed, because the fixed and movable parts 31 and 32 touch at two tangent points PA and QA located almost at their lateral ends. The profiles of the fixed and moving parts 31 and 32 are chosen so that, for a circular translation of the moving part 32, the points of tangency remain in moving and sliding towards each other along the profiles, to take for example the position represented in FIG. 7B after a quarter turn, where we observe that the points of tangency (then PB, QB) are at the top of the lobes 33 and 34, or at the bottom of the hollows 35 and 36. The chamber 30 has been significantly reduced both in length and in width, which implies that its contents have been largely pushed back towards the pulsation tube through the orifice 37. Another quarter turn imposed on the moving part 32 and the assembly takes the arrangement of FIG. 7C, where the points of tangency (then PC and QC) are re] oιgn at the location of the orifice 37. The entire contents of chamber 30 were then expelled. The circular translational movement is then accompanied by the separation of the fixed and mobile parts 31 and 32, which is shown after a third quarter turn in FIG. 7D, and the chamber 30 opens and takes a maximum volume which - favors the admission of gas. We then return to the state of FIG. 7A, where the chamber 30 closes at the points of tangency and where the delivery begins again.

A concrete implementation of this principle is described in Figure 8. The fixed part 31 is screwed to an enclosure 40 which houses a movable assembly 41. The latter consists of a motor 42 whose motor shaft 43 is extended by an eccentric part 44 carrying, by means of a pair of bearings 45, a movable block 46 to which the movable part 32 is screwed. The movable block 46 is therefore suspended from the motor shaft 43 with a freedom to rotate, which is countered by a bellows 47 uniting an external collar 48 to the movable block 46 with a cover 49 of the enclosure 40: the bellows 47 is has torsional rigidity sufficient to reduce almost completely the rotations of the movable block 46 and of the movable part 32, to a sufficiently low level so that it can be estimated that the movable part 32 is only subjected to a circular translation produced by the rotation of the part eccentric 44 of the motor shaft 43. In addition, the bellows 47 has the advantage of enclosing the bearings 45 and another pair of bearings 50, disposed between a descending tab 51 of the cover 49 and a pair of eccentrics 52 of the motor shaft 43, which maintain the eccentric position of the eccentric part 44: the grease of the bearings cannot end up in the pressure generation chamber 30 nor in the other thermally active parts of the machine, where its intrusion could be very damaging .

The orifice 37 opens into a thermal regenerator 53, then, after a neck 54, into a pulsation tube 55. The regenerator and the pulsation tube 55 pass through an insulating wall 56 of a cold room inside which finds the neck 54, to which a cold source 57 is attached. A hot source 58 is located against the bottom of the pulsation tube 55, outside the heat-insulating wall 56 and the cold room; a pipe 59 connects the pulsation tube 55 inside the enclosure 40 which forms the reservoir 23 of FIGS. 6B and 6C. The gas which is the subject of back-ups and admissions in alternating directions through orifice 37, between the refrigerating machine and the pressure generation chamber 30, can be helium at 5 bars and at ambient temperature, and the cold room can be at a temperature of -20 ° C. Nitrogen or air can also be considered. The bellows 47 may contain air, but it is preferable that its pressure is similar to that of the rest of the contents of the enclosure 40 so that it is not not stiff. The pressure generation chamber 30 can in this example have a maximum volume of 30 cm ^J , and the motor 42 can rotate at 1500 rpm. It has hitherto been assumed that contact was effective between the profiles facing the fixed 31 and movable 32 parts, which is possible if they are coated with a low friction product such as plastic or graphite, but of small clearances (0.1 mm for example) are tolerable, the points of tangency P and Q then being points of quasi-tangency.

As in the usual refrigerating machines, a thermometer 60 controls the starting of the motor 42 by means of an electrical box 61 as soon as a rise in the temperature in the cold room is observed.

The following two figures 9A and 9B are partial views which show that the bellows 47 is not the only suitable means for stopping or reducing the rotation of the moving part 32: in the embodiment of FIG. 9A, the movable block 46 takes a different shape and the reference 70; it is suspended from the eccentric part 44 of the motor shaft 43 by a single bearing 45, but it is also suspended from an axis 71 of another eccentric 72 suspended from the descending tab 51 (of slightly modified shape). Bearings 73 and 74 are arranged between the axis 71 and the movable block 70, and between the eccentric 72 and the descending tab 51, to tolerate the relative rotations of these parts. As the eccentric 72 is exactly similar to the eccentrics 52, parallel to them and in phase with them, the rotation of the motor shaft 43 causes concomitant rotations of the eccentrics 52 and 72 and therefore an absolutely pure circular translation of the movable block 70. A bellows can still be added to confine the 7 » _Λ1 , - _™ «

PCT / FR96 / 01084

15

bearings 50, 45, 73 and 74 in a closed volume, but as it would not have any other utility, one can consider not to use it but to use dry bearings or bearings closed by sealing lips .

FIG. 9B shows a movable block 80 joined, by two opposite ends 81 and 82, at the top and at the bottom of the enclosure 40 by four springs 83. The springs 83 are arranged symmetrically; for example, their points of attachment to the enclosure 40 may be located in a plane passing through the axis of the motor shaft 43. When the latter rotates, the springs 83 are stretched sideways but maintain a state of equilibrium in rotation of the movable block 80. In this embodiment, there is only an eccentric 52 and a bearing 45 and 50 of each species to support the motor shaft 43 and suspend the movable block 80.

A very different design of this driving part of the refrigerating machine is illustrated in FIG. 10: the moving part 32 is not connected to a drive shaft and the internal face of the cylindrical wall 91 of the enclosure 40 carries the windings 92 an electric motor, the poles 93 of which are fixed in a crown to an eccentric 94 in the form of a socket surrounding the moving part 32. Sealed and concentric bearings 95 and 96 which respectively connect the eccentric 94 to the moving part 32 and to the cylindrical wall 91 allow these to be suspended therefrom; a bellows 90 connecting the moving part 32 to the cover 49 is intended to maintain the moving part 32 in an almost unchanging angular position, as in previous embodiments. Such a device makes it possible to very substantially reduce the radial inertial forces which appear when the motor rotates and strongly load the motor shaft, those of the eccentric 94 counterbalancing those of the moving part 32.

Balancing of the linear components of the inertial forces in the plane of rotation of the parts can be undertaken to make them equal and completely cancel their result. Bearings 95 and 96 can then be replaced by gas or magnetic bearings. If ordinary bearings, lubricated with grease, are used, it is preferable to isolate them from the thermally active parts by a second bellows 97 to be dimensioned suitably connecting the moving part 32 to the bottom 98 of the enclosure 40, thus replacing the first bellows 90 and surrounding the fixed part 31. FIG. 11 illustrates a slightly different embodiment intended to operate in cryogenics, by thermally insulating the driving parts of the machine, which work at room temperature or a little lower, from the thermally active parts which use a gas very cooled throughout the thermodynamic cycle.

An external enclosure 100 is lined on three sides (except on a cover 115) by an internal enclosure 101, the fixed part 31 of which forms the bottom. The moving part 32, like the other moving elements, is housed in the internal enclosure 101: there is a motor 103, a motor shaft 104 terminated by an eccentric part 105, a pair of bearings 106, installed in a tubular part 116 descending from the cover 115 to support the motor shaft 104, a third bearing 107 to suspend a movable block 108 from the eccentric part 105 and a bellows 109 uniting the movable block 108 to the cover 115 to hold it in rotation with the movable part 32 , which is suspended from it by a mast 117. This mast 117 and the cylindrical wall 110 of the internal enclosure 101 are constructed of a material which is poor conductor of heat such as stainless steel so that the fixed and mobile parts 31 and 32 remain at a very low temperature, maintained by a circulation of nitrogen liquid in a coil 111 wound around the fixed part 31 and the bottom of the internal enclosure 101.

All the elements of the refrigerating machine are suspended from the fixed part 31 and extend under the internal enclosure 101, and the cold source carries an element 112 to be cooled, which can be a radiation detector from an astronomical telescope oriented towards a porthole 113 of the external enclosure 100. This device makes it possible to reach temperatures of 4 Kelvin.

Other arrangements can be proposed. Thus, the profiles of the fixed and moving parts can be different. One possibility is to shape them into spiral arcs or circular arcs. Another possibility is to multiply them according to the principle of Figures 12 and 13.

In FIG. 12, the fixed and mobile parts, here referenced 131 and 132, are stepped to form successive vertical profiles 133 and 134. Each vertical profile 133 of the fixed part 131 faces one of the vertical profiles 134 of the movable part 132 and forms with it a particular pressure generation chamber 130. Such an arrangement makes it possible to multiply the pumped volume without causing the difficulties of machining associated with the enlargement of a single pressure generation chamber; or else to order different refrigeration machines, as shown: each chamber 130 communicates through an orifice 137 with a particular machine 138 similar to that of FIG. 8 and comprising in particular a tube to. pulsation, a thermal regenerator and hot and cold sources.

The vertical profiles 133 and 134 are similar to those of FIGS. 7A to 7D or to those derived therefrom and have similar properties. The fixed and mobile parts 131 and 132 can be constructed in one piece or formed from superimposed plates, each of which carries one of the vertical profiles 133 or 134. Another embodiment with a similar effect is illustrated in FIG. 13. Each of the fixed and mobile parts 231 and 232 carries vertical profiles 233a, 233b. and 234a, 234b successive at the same height and which are cut on opposite faces of projections of the parts 231 and 232; these projections penetrate between projections neighboring the other of the parts. Thus, particular chambers 230a are formed between the profiles 233a and 234a and other particular chambers 230b, which alternate with the previous ones, are formed between the profiles 233b and 234b.

The profiles 233a, 233b and 234a, 234b are also similar to those of FIGS. 7A to 7D or their equivalents. The private rooms 230a have volumes which vary together and in phase opposition with the volumes of the private rooms 230b. The particular chambers 230a are provided with orifices 237a which communicate with a common collector 235a and with a single refrigerating machine 238a. Similarly, the other particular chambers 230b are provided with orifices 237b which communicate with another common manifold 235b and with another single refrigerating machine 238b. Of course, each of the orifices 237a and 237b could lead to a particular refrigerating machine, and conversely the orifices 137 in FIG. 12 could lead to a single refrigerating machine.

Claims

7 PC17FR96 / 01084 1 9 CLAIMS 1. Machine for transferring heat from a cold source (57) to a hot source (58), comprising a pulsation tube (55), free and occupied by a column of gas passing through the two sources, an oscillator of pressure composed of a fixed portion (31) and a movable portion (32) delimiting a pressure generation chamber (30) with variable volume communicating with the pulsation tube by a thermal regenerator (53) according to delivery alternatives and gas inlet, characterized in that the movable portion is driven in circular translation by a motor (42, 92, 93, 103) and an eccentric transmission (43, 44, 52, 14, 104, 105). 2. Refrigeration machine according to claim 1, characterized in that the fixed and movable portions delimit several pressure generation chambers, which communicate with separate pulsation tubes. 3. Machine according to claim 1, characterized in that the fixed and movable portions delimit several pressure generation chambers, which communicate with the same pulsation tube. 4. Machine according to any one of claims 1 to 3, characterized in that the fixed and movable portions delimit the pressure generation chamber by curvilinear profiles at two points of tangency or quasi-tangency (P, Q) which s 'approach each other during part of the circular translation. 5. Machine according to claim 4, characterized in that the points of tangency or quasi-tangency join before a communication orifice (37) to the pulsation tube (55). 6. Machine according to any one of claims 4 or 5, characterized in that the curvilinear profiles are substantially in the form of a sinusoid and comprise at least one rounded lobe (33, 34) adjacent to a rounded recess (35, 36) more large. 7. Machine according to any one of claims 1 to 6, characterized in that the movable portion (32) is connected to the motor (42, 103) by a motor shaft (43, 104) with eccentric part (44, 105) and at least one bearing (45). 8. Machine according to claim 7, characterized in that the movable portion is connected to the motor (92, 93) by an eccentric (94) which surrounds the movable portion (32). 9. Machine according to claim 8, characterized in that the motor (92, 93) drives the eccentric in rotation and a bearing (97) connects the movable portion to the eccentric. 10. Machine according to claim 9, characterized in that the movable portion and the eccentric are balanced so as to reduce linear components of inertial force in a plane of rotation of the movable portion. 11. Machine according to any one of claims 1 to 10, characterized in that the movable portion is joined to a fixed part (49) of the machine by a connection (47, 71, 72, 83, 90) opposing rotations of the movable portion (32). 12. Machine according to claim 11, characterized in that the connection comprises a bellows (47, 97, 109) separating the pressure generation chamber (30) from the bearings (45, 50, 95, 96, 106). 13. Machine according to claim 11, characterized in that the connection comprises springs (83). 14. Machine according to claims 8 and 11, characterized in that the connection comprises a second eccentric (72), passive, parallel and similar to the first and in phase with it. 15. Machine according to any one of claims 1 to 14, characterized in that it comprises dry or sealed bearings (73, 74). 16. Machine according to any one of claims 1 to 14, characterized in that it comprises gas or magnetic bearings (95, 96). 17. Machine according to any one of claims 1 to 16, characterized in that the fixed portion (31) is cooled (111) to a temperature different from the ambient temperature. 18. Machine according to any one of claims 1 to 17, characterized in that the fixed and movable portions (31, 32) are in contact by surfaces coated with a material with a low coefficient of friction. 19. Machine according to any one of claims 1 to 17, characterized in that the fixed and mobile portions (31, 32) are separated by a slight clearance.