Piston housing a temperature and / or pressure sensor for a thermodynamic characterisation device

Abstract

The invention relates to a device, preferably for the thermodynamic characterisation of a fluid, comprising a piston (7) and a pressure and / or temperature sensor (33) housed inside the piston (7). The invention also relates to a method for assembling such a sensor (33).

Description

[0001] Description

[0002] Title: Piston housing a temperature and / or pressure sensor for a thermodynamic characterization device

[0003] Technical field

[0004] The invention relates to the field of temperature and / or pressure measurement.

[0005] The invention is of particular interest in the sector of thermodynamic analysis of a fluid, for example oil sampled during exploration or exploitation drilling.

[0006] State of the prior art

[0007] Conventional equipment for thermodynamic fluid analysis has a volume and mass that does not allow its transport to the sampling site, making it necessary to send samples to remote analysis laboratories.

[0008] Attempts have been made to miniaturize this equipment so that in situ analyses can be carried out.

[0009] In this context, a compact device has been proposed, described in document FR3001546A1, equipped with a compression chamber designed to receive a volume of fluid to be analyzed not exceeding 1 cm 3 This device includes a sensor with a probe designed to be moved towards the chamber to measure the temperature of the fluid.

[0010] Such a temperature detection mechanism is complex to implement.

[0011] Statement of the invention

[0012] The invention aims to provide a measurement technique, particularly temperature measurement, which is reliable and compatible with a compact thermodynamic characterization device.

[0013] To this end, the invention relates to a device comprising a chamber capable of receiving a fluid, a piston configured to be able to modify the volume of the chamber and a pressure and / or temperature sensor. According to the invention, the sensor is housed in the piston so as to have an external surface which delimits the chamber.

[0014] Such an arrangement of the sensor makes it possible to both simplify the device and to carry out reliable and precise measurements.

[0015] The invention makes it possible in particular to avoid dead volumes in the chamber.

[0016] It is preferred that the external surface of the sensor is flush with an external surface of the piston which also delimits the chamber.

[0017] In one embodiment, the outer surface of the sensor extends in a plane perpendicular to a translation direction of the piston.

[0018] In one embodiment, the sensor forms a cylindrical pellet.

[0019] Said external surface of the piston may be annular.

[0020] In one embodiment, the sensor and the piston are attached to each other using a weld bead.

[0021] Preferably, this weld bead is configured to delimit the chamber.

[0022] In one embodiment, the piston includes an orifice configured to receive one or more cables for connecting the sensor to a measurement data processing and / or analysis module.

[0023] The sensor preferably comprises, on the one hand, a body and on the other hand, one or more measuring instruments connected to the body of the sensor.

[0024] It is preferred that said external surface of the sensor is formed by the body.

[0025] In one embodiment, the sensor body comprises a cavity receiving the measuring instrument(s).

[0026] In one embodiment, the measuring instruments comprise a pressure transducer, such as a strain gauge, and / or a temperature detector, such as a platinum resistance probe. In one embodiment, the piston has a diameter of between 1 mm and 100 mm, preferably less than 50 mm, more preferably less than 30 mm, for example equal to 25 mm.

[0027] In one embodiment, the sensor has a diameter of between 1 mm and 100 mm, preferably less than 50 mm, more preferably less than 20 mm, for example equal to 12 mm.

[0028] In one embodiment, the device is intended for the thermodynamic characterization of a fluid contained in the chamber, the sensor being configured to measure the pressure and / or the temperature of the fluid received in the chamber.

[0029] The device can be implemented to characterize many types of fluid, including but not limited to hydrocarbons such as oil.

[0030] According to another aspect, the invention relates to a method of assembling a device as defined above.

[0031] The method preferably comprises inserting the sensor into a housing formed by the piston, for example in an insertion direction parallel to a direction of movement of the piston.

[0032] In one embodiment, the method comprises attaching the sensor to the piston, preferably by laser welding.

[0033] In one embodiment, the method comprises fixing the measuring instrument(s) to the sensor body, preferably by gluing.

[0034] Other advantages and characteristics of the invention will appear on reading the detailed, non-limiting description which follows.

[0035] Brief description of the drawings

[0036] The following detailed description refers to the attached drawings in which:

[0037] Fig. 1 is a partial longitudinal sectional view of a thermodynamic characterization device according to the invention, along a sectional plane passing through a translation axis of a piston of the device; Fig. 2 is an enlargement of a part of the device of Figure 1, centered on the piston, the cut parts being shown without hatching in order to facilitate the visualization of the references;

[0038] Fig. 3 is an enlargement of a portion of the piston of the device of Figure 1, centered on the body of a sensor housed in the piston.

[0039] Detailed description of embodiments

[0040] Figure 1 shows a device 1 according to the invention, intended for the thermodynamic characterization of a fluid.

[0041] The device 1 comprises a fixed structure and a mobile structure, relative to the fixed structure, in a longitudinal direction D1. The direction DI defines a first direction SI of movement of the mobile structure, going from the top to the bottom of figure 1, and a second direction S2 going from the bottom to the top of figure 1.

[0042] In this non-limiting example, the fixed structure comprises different parts 3-6 assembled to each other in the manner illustrated in FIG. 1, the mobile structure comprising a piston 7 and a tie rod 8 secured to each other in longitudinal translation, that is to say in the direction D1.

[0043] With reference to Figure 2, which shows an enlargement of a part of these fixed and mobile structures, centered on the piston 7, the part 3 of the fixed structure, also called “body”, comprises an opening which passes through it from one side to the other in the direction Dl, so as to extend around an axis Al.

[0044] The opening of the body 3 comprises a bore 11 of axis Al and diameter XI which extends over a longitudinal portion of dimension X2, as well as a bore 12 of axis Al and diameter X3 which extends over a longitudinal portion of dimension X4.

[0045] In this non-limiting example, the dimensions XI, X2, X3 and X4 are respectively equal to 28 mm, 28 mm, 25 mm and 4.55 mm.

[0046] The diameter X3 of the bore 12 being less than the diameter XI of the bore 11, the body 3 forms a shoulder 13 defining an annular bearing surface which extends in a plane perpendicular to the direction D1. In this example, the opening of the body 3 comprises a counterbore 14 through which the bore 11 opens at a first longitudinal end of the body 3, also called the “upper end”. The counterbore 14 forms a shoulder 15 which defines an annular bearing surface extending in a plane perpendicular to the direction D1.

[0047] The opening of the body 3 also comprises a counterbore 17 through which the bore 12 opens at a second longitudinal end of the body 3, also called the “lower end”. The counterbore 17 forms a shoulder 18 which defines an annular bearing surface extending in a plane perpendicular to the direction D1.

[0048] The part 4 of the fixed structure, also called a “porthole” because it is configured to allow viewing of the interior of the chamber 41, is housed in the counterbore 17 of the body 3, so that a surface 21 of the porthole 4 rests on the annular surface formed by the shoulder 18.

[0049] The porthole 4 thus closes the opening of the body 3 at its lower end.

[0050] The piston 7 is received in a housing of the fixed structure here formed by the bores 11 and 12 and by the counterbore 14 of the body 3.

[0051] An annular seal 31 is arranged in the bore 11 so as to extend radially between the piston 7 and the surface of the body 3 which forms this bore 11.

[0052] The device 1 comprises a sensor 33 housed in the piston 7 so as to delimit with the piston 7 the chamber 41. The sensor 33 and the piston 7 are described further below with reference to figure 3.

[0053] The device 1 thus forms an annular chamber 41 which is delimited radially by the surface of the body 3 forming the bore 12. Longitudinally, the chamber 41 is delimited on the one hand by the surface 21 of the porthole 4 and, on the other hand, by the end of the piston 7 receiving the sensor 33.

[0054] The piston 7 is mounted to slide in the direction D1, and consequently along the axis A1 along which it extends. Figures 1 and 2 show the piston 7 in a first position, in which the chamber 41 has a volume having a first value. A movement of the piston 7 in the direction of the porthole 4, to a second position (not shown), makes it possible to reduce the volume of the chamber 41 to a second value lower than the first value.

[0055] In this non-limiting example, the volume of the chamber is of the order of 1.5 cm 3 when the piston 7 is in the first position and substantially zero when the piston 7 is in the second position, the stroke of the piston 7 between the first and second positions being 3 mm.

[0056] Chamber 41 thus forms a compression chamber capable of containing a fluid under pressure.

[0057] In the example of Figure 1, the piston 7 is controlled using an actuation system comprising an electric motor equipped with an encoder (not shown).

[0058] The actuation system comprises a transmission mechanism configured to transform a rotary movement of a motor shaft (not shown) into a translation of the piston 7 along D1.

[0059] In this non-limiting example, the transmission mechanism comprises a screw 52 configured to be driven in translation along an axis A2, parallel to the axis A1, under the action of a nut 53. The drive shaft drives a screw (not shown), which cooperates with a wheel (not shown) secured to the nut 53, so as to form a gear of the wheel and worm type.

[0060] The screw 52 cooperates with the nut 53 which is integral with the part 6 of the fixed structure, so that a rotation of the nut 53 around the axis A2 causes a translation of this screw 52 along D1.

[0061] The transmission mechanism comprises in this example a lever arm 55 having a pivoting surface bearing on an axis 56 secured to the tie rod 8. The axis 56 defines an axis of rotation perpendicular to the direction DI and passing through the translation axis A1. The lever arm 55 is thus connected to the tie rod 8 according to a pivot connection.

[0062] In the example of Figure 1, the pivoting of the lever arm 55 on the fixed structure is ensured by a connecting rod 57 arranged between one end of the lever arm 55 and the part 5, also called “support”. Such a connecting rod 57 makes it possible to improve the distribution of loads during the movement of the piston 7. In a variant not shown, the lever arm 55 can be connected to the screw 52, ​​to the tie rod 8 or to the piston 7, as well as to the fixed structure of the device 1 according to any conventional technique not using such a connecting rod 57.

[0063] More generally, the transmission to the piston 7 of the translational movement of the screw 52 by the lever arm 55 makes it possible to multiply the force transmitted to the piston 7 and in particular to reduce the size of the engine.

[0064] The device 1 further comprises a play-compensating spring 61 formed by a stack of conical washers which are configured to exert a tensile force on the tie rod 8, and consequently on the piston 7, in the direction S2 of the direction D1.

[0065] Thus, when the piston 7 is moved in the direction SI under the action of the lever arm 55, the movable structure compresses the spring 61 which is dimensioned to maintain a load on this movable structure and on the lever arm 55, in order to prevent a play present in the transmission mechanism from causing measurement errors.

[0066] The device 1 also comprises circuits and valves, not shown, provided on the one hand to introduce a fluid sample into the chamber 41 for the purpose of analysis, for example, and, on the other hand, to evacuate the fluid from the chamber 41, in particular at the end of the analysis.

[0067] In a manner known per se, the device 1 comprises other organs, not shown, including, but not limited to:

[0068] - a system for heating the fluid contained in chamber 41, and / or

[0069] - a high-definition camera for studying phase changes and / or sedimentations of the fluid contained in the chamber 41, and / or - a system for stirring the fluid contained in the chamber 41, for example by vibrations, and / or

[0070] - a system for cooling the fluid contained in chamber 41, and / or

[0071] - a gasometer connected to room 41 in order to carry out additional tests.

[0072] Generally speaking, the device 1 makes it possible to carry out thermodynamic analyses of a fluid such as a hydrocarbon oil, in particular by analyzing the phase behavior during a reduction in the volume of the chamber 41 under the action of a movement of the piston 7.

[0073] Such analyses can be carried out directly on the oil drilling site, for example, given the size and mass of the device 1 which facilitate its transport. In this example, the device 1 has a size of less than 0.1 m 3 and a total mass of around fifteen kg.

[0074] The invention relates more specifically to the subassembly formed by the piston 7 and the sensor 33, described below with reference to FIG. 3.

[0075] The sensor 33 comprises a body, which is the only part of the sensor 33 shown in Figures 1-3, as well as measuring instruments connected to the body which thus constitutes a support for these measuring instruments.

[0076] In this non-limiting example, the body of the sensor 33 is in the form of a cylindrical pellet with a diameter X5 equal to 12 mm, a thickness X6 equal to 2 mm and having the axis of symmetry A1.

[0077] The body of the sensor 33 has two surfaces 71 and 72 which define two longitudinal ends of the body and which are spaced along Al by a distance constituting its thickness X6. The body of the sensor 33 also comprises a surface 73 which delimits the body radially, the surface 73 extending circumferentially around the axis Al which forms an axis of symmetry of this surface 73.

[0078] The body of the sensor 33 comprises a counterbore 75 which opens onto the surface 72 of the body, also called the “internal surface”. In this particular example, the counterbore 75 has a diameter X7 of 5.3 mm and a depth X8 of 0.85 mm.

[0079] The body of the sensor 33 comprises an outer chamfer forming a surface which connects the surfaces 71 and 73 to each other. In a non-limiting manner, this outer chamfer forms an angle of 45° relative to each of the surfaces 71 and 73 and having a dimension of 0.3 mm according to A1.

[0080] In this example, the piston 7 comprises a cavity in the form of a counterbore opening onto the surface 32, also called the “external surface” of the piston 7.

[0081] This counterbore forms a shoulder 81 defining a depth, that is to say a distance along Al between the shoulder 81 and the surface 32, which corresponds substantially to the dimension X6 of the body of the sensor 33.

[0082] The counterbore is radially delimited by a surface 82 of the piston 7 which extends circumferentially around the axis Al and which has a diameter slightly greater than the diameter X5 of the body of the sensor 33 in order to be able to insert it there.

[0083] The external surface 32 of the piston 7 thus has an annular geometry with axis Al.

[0084] The piston 7 comprises an inner chamfer forming a surface which connects the surfaces 32 and 82 to each other. In this example, this inner chamfer forms an angle of 45° with respect to each of the surfaces 32 and 82 and has a dimension of 0.3 mm according to A1.

[0085] The piston 7 also includes an orifice 83 of diameter X9 which passes through it along the axis Al so as to open into the counterbore of the piston 7, at the level of the shoulder 81 which thus forms an annular surface of axis Al. In this example, X9 is greater than X7.

[0086] The body of the sensor 33 is housed in the piston 7 so as to extend radially inside the surface 82 of the piston 7, the internal surface 72 of the body of the sensor 33 bearing on the shoulder 81 so that its surface 71, also called “external surface”, is flush with the external surface 32 of the piston 7. In this configuration, said external chamfer formed by the body of the sensor 33 and said internal chamfer formed by the piston 7 are opposite each other so as to together define a circular groove 90, in this example of triangular section.

[0087] In this example, the sensor body 33 and the piston 7 are fixed to each other by laser welding so as to form a weld bead extending in this groove 90.

[0088] It results from this assembly that the chamber 41 is delimited, longitudinally on the side of the piston 7, by a composite surface formed both by the external surface 32 of the piston 7, by the external surface 71 of the body of the sensor 33 and by the weld bead which connects the body of the sensor 33 and the piston 7 to each other.

[0089] In this example, surfaces 32 and 71 are both planar and extend in a plane perpendicular to axis A1.

[0090] The weld bead is in this example treated so as to form an external surface extending in the same plane as the surfaces 32 and 71, that is to say so that said composite surface which delimits the chamber 41 is flat.

[0091] In this example, the measuring instruments of the sensor 33, not shown in Figures 1-3, include a strain gauge, or strain gauge, as well as a platinum resistance probe of the “PT100” type.

[0092] The strain gauge comes in the form of a pellet with a diameter of approximately 5 mm and a thickness of a few tenths of a mm.

[0093] These measuring instruments are here arranged one on top of the other in the cavity 75 of the body of the sensor 33 and glued to each other and to the body so as to keep them fixed relative to the piston 7.

[0094] These measuring instruments are connected to a signal conditioning module (not shown) by cables (not shown) which pass through the orifice 83 made in the piston 7 as well as an orifice 91 made in the tie rod 8.

[0095] The sensor 33 thus makes it possible to measure the pressure and temperature of the fluid received in the chamber 41. Of course, numerous variants can be made to the device which has just been described. In particular, the sensor 33 can comprise a body having another geometry and / or carrying one or more measuring instruments not limited to those described above. For example, the sensor 33 can comprise only a pressure transducer or a temperature detector.

Claims

Claims 1. Device (1) comprising a chamber (41) capable of receiving a fluid, a piston (7) configured to be able to modify the volume of the chamber (41) and a pressure and / or temperature sensor (33), characterized in that the sensor (33) is housed in the piston (7) so as to have an external surface (71) which delimits the chamber (41).

2. Device (1) according to claim 1, in which the external surface (71) of the sensor (33) is flush with an external surface (32) of the piston (7) which also delimits the chamber (41).

3. Device (1) according to claim 1 or 2, wherein the external surface (71) of the sensor (33) extends in a plane perpendicular to a direction (Dl) of translation of the piston (7).

4. Device (1) according to any one of claims 1 to 3, in which the sensor (33) forms a cylindrical pellet.

5. Device (1) according to any one of claims 1 to 4, wherein said external surface (32) of the piston (7) is annular.

6. Device (1) according to any one of claims 1 to 5, wherein the sensor (33) and the piston (7) are fixed to each other using a weld bead configured to delimit the chamber (41).

7. Device (1) according to any one of claims 1 to 6, wherein the piston (7) comprises an orifice (83) configured to receive one or more cables intended to connect the sensor (33) to a module for processing and / or analyzing measurement data.

8. Device (1) according to any one of claims 1 to 7, in which the sensor (33) comprises on the one hand a body forming said external surface (71) of the sensor (33) and on the other hand one or more measuring instruments connected to the body of the sensor (33).

9. Device (1) according to claim 5, in which the body of the sensor (33) comprises a cavity receiving the measuring instrument(s).

10. Device (1) according to claim 5 or 9, wherein the measuring instruments comprise a pressure transducer, such as a strain gauge, and / or a temperature detector, such as a platinum resistance probe.

11. Device (1) according to any one of claims 1 to 10, in which the piston (7) has a diameter between 1 mm and 100 mm, preferably less than 50 mm, more preferably less than 30 mm, for example equal to 25 mm and / or in which the sensor (33) has a diameter between 1 mm and 100 mm, preferably less than 50 mm, more preferably less than 20 mm, for example equal to 12 mm.

12. Device (1) according to any one of claims 1 to 11, intended for the thermodynamic characterization of a fluid contained in the chamber (41), the sensor (33) being configured to measure the pressure and / or the temperature of the fluid received in the chamber (41).

13. Method of assembling a device (1) according to any one of claims 1 to 12, comprising inserting the sensor (33) into a housing formed by the piston (7).

14. Method according to claim 13, comprising fixing the sensor (33) to the piston (7), preferably by laser welding.

15. Method according to claim 13 or 14, for assembling a device (1) including the features of claim 8, comprising fixing the measuring instrument(s) to the body of the sensor (33), preferably by gluing.

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