Throttle valve

Abstract

The invention relates to a throttle valve (1) comprising a stem (2) that is arranged to move in translation, along a longitudinal axis (x'x), inside a hollow cylinder (75) such that a first end (3) of the stem closes a pipe (4) located downstream of the hollow cylinder with respect to a direction (x'x), referred to as the closing direction, connecting a second end (5) of the stem to the first end of the stem. The second end of the stem is located upstream of the hollow cylinder with respect to the closing direction (x'x), and is intended to be coupled with an element that is capable of moving the stem in translation so as to regulate a rate of escape of a fluid intended to flow through the pipe. The valve comprises a stack (7) comprising, in a direction (xx1), referred to as the opening direction, connecting the first end of the stem to the second end of the stem, an anti-extrusion ring (71), a sealing ring (72), a compression ring (73) and a part (74) that is arranged so as to exert pressure on the compression ring such that the compression ring compresses the sealing ring, wherein each of the elements of the stack comprises a through-bore, and the bores passing through the elements of the stack constitute the hollow cylinder.

Description

[0001] DESCRIPTION

[0002] TITLE: Throttling Valve

[0003] Technical field

[0004] The present invention relates to the field of throttling valves.

[0005] The present invention relates to a throttle valve for devices for thermodynamic characterization of a fluid. A preferred, but not exclusive, field of application is that of the thermodynamic analysis of a viscous fluid, for example an oil, sampled during exploration or exploitation drilling.

[0006] State of the prior art

[0007] Thermodynamic fluid analysis devices are devices designed to analyze hot fluids under pressure. One area of ​​application for these devices is fluid samples taken from underground. One objective of these analysis devices is to reproduce the conditions in which the fluids were found when they were sampled. The pressures to which these fluids are subjected are typically around 1000 bars.

[0008] In the state of the art, bulky and non-transportable thermodynamic analysis devices are known, typically with a footprint of several square meters. This therefore requires the transport of samples from the collection location to the analysis device.

[0009] State-of-the-art thermodynamic fluid analysis devices require the analysis of large fluid sample volumes, typically in the order of 100 cubic centimeters. Recently, miniaturized equipment has been proposed to perform analyses directly at the sampling site.

[0010] 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 reduction in size requires precision, both in terms of pressure and volume measurement and pressure and volume regulation, which is much greater than for analysis devices using a large fluid sample volume. A resolution of around 10 -3cubic centimeters is required for state-of-the-art non-transportable thermodynamic analysis devices. The resolution required for miniature devices is of the order of 10 -5 cubic centimeters.

[0011] An aim of the invention is, in addition, to propose a throttling valve:

[0012] - designed for use under high fluid pressures, typically greater than 500 bars and up to 1000 bars, and / or

[0013] - providing high precision and control of the fluid leakage rate through the throttle valve, and / or

[0014] - having minimal bulk, typically a total diameter of 30 mm and a length of less than 170 mm, and / or

[0015] - having a low pipe volume and / or arranged to be mounted on fluid pipes of small cross-section, typically of the order of 0.2 mm 2 .

[0016] Presentation of the invention

[0017] For this purpose, a throttling valve is proposed comprising a needle arranged to translate, along a longitudinal axis of the needle, in a hollow cylinder of the throttling valve, so that a first end of the needle closes or releases a conduit located downstream of the hollow cylinder relative to a direction x'x, called the closing direction, connecting a second end of the needle to the first end of the needle.

[0018] The second end of the needle is:

[0019] - located upstream of the hollow cylinder relative to the direction of closure, and

[0020] - intended to be coupled with an element capable of translating the needle in the hollow cylinder so as to regulate a leakage rate of a fluid intended to circulate in the conduit.

[0021] The throttle valve further comprises a stack. The stack comprises or is formed or consists of, in a direction xx', called the opening direction, connecting the first end of the needle to the second end of the needle:

[0022] - an anti-extrusion ring,

[0023] - a sealing ring,

[0024] - a compression ring, and

[0025] - a part arranged to exert pressure on the compression ring so that said compression ring compresses the sealing ring. Each of the elements of the stack comprises a through bore. The through bores of the elements of the stack constitute the hollow cylinder.

[0026] Preferably, the longitudinal axis of the needle is coincident with the longitudinal axis of the throttle valve.

[0027] A diameter of the hollow cylinder may vary along the axis of revolution of the hollow cylinder. Preferably, the axis of revolution of the hollow cylinder coincides with the longitudinal axis of the needle.

[0028] A conduit may be understood to mean any hollow element adapted for the transit of a fluid within it, such as, for example, a conduit, a channel, a pipe or a pipeline.

[0029] Preferably, the conduit extends along the longitudinal axis of the needle.

[0030] It can be heard by releasing the duct open the duct.

[0031] Preferably, the throttle valve and / or the needle and / or the first end of the needle is arranged to close or release the conduit.

[0032] The throttle valve may or may not include the conduit. The conduit may or may not be part of, or included in, the throttle valve. The throttle valve may be intended to cooperate with or be mounted on a conduit.

[0033] Preferably, the conduit comprises an orifice formed in a wall of a portion of the conduit, called the proximal portion. Preferably, the wall of the proximal portion of the conduit in which the orifice is formed is a side wall, relative to the longitudinal axis, of the conduit.

[0034] Preferably, the orifice is located downstream of the anti-extrusion ring relative to the sealing direction x'x.

[0035] Preferably, the conduit comprises a portion, called the distal portion, located upstream of the proximal portion of the conduit in the opening direction xx'.

[0036] Preferably, the distal portion and the proximal portion of the conduit are adjoining and communicate.

[0037] Preferably, the first end of the needle is arranged to translate, along an axis of revolution of the proximal portion of the conduit, in said proximal portion of the conduit. More preferably, the needle is arranged to close or release the orifice by translation of the first end of the needle in the proximal portion of the conduit.

[0038] Preferably, the axis of revolution of the proximal portion of the conduit and an axis of revolution of the distal portion of the conduit are coincident and, more preferably, form an axis of revolution of the conduit. A diameter of the conduit may vary along the axis of revolution of the conduit. Preferably, the axis of revolution of the conduit is coincident with the longitudinal axis of the needle.

[0039] Preferably, the first end of the needle is arranged to translate, preferably only partially, into the distal portion of the conduit. Preferably, the first end of the needle is arranged to close or release an opening through which the proximal and distal portions of the conduit communicate. Preferably, an apex of the first end of the needle is arranged to penetrate into the distal portion of the conduit by translation of the needle. More preferably, only the apex of the first end of the needle is arranged to penetrate into the distal portion of the conduit. Preferably, the apex of the needle is arranged to close or release the opening through which the proximal and distal portions of the conduit communicate.

[0040] Preferably, the conduit is intended to connect two separate volumes or chambers. Preferably, one of the two chambers, called upstream chambers, is intended to contain fluids having a pressure greater than or equal to 200 bars, more preferably 500 bars, more preferably 1000 bars and the other of the two chambers, called downstream chamber, is intended to contain fluids having a pressure lower than the pressure of the upstream chamber, typically fluids having a pressure less than or equal to 200 bars, preferably 10 bars, more preferably 1 bar.

[0041] Preferably, the proximal portion of the conduit communicates with the downstream chamber through the orifice. Preferably, the proximal portion of the conduit communicates with the upstream chamber through the distal portion of the conduit.

[0042] Preferably, an axis of revolution of the orifice forms an angle of between 40 and 50° relative to the longitudinal axis.

[0043] Preferably, the throttle valve according to the invention is suitable or adapted to be mounted or to cooperate with any type of conduit.

[0044] Preferably, the needle is arranged to translate in the hollow cylinder according to a translation-rotation movement, the element with which the needle is intended to be coupled being capable of putting the needle into translation-rotation movement. Preferably, the bore of the part arranged to exert pressure on the compression ring comprises a tapping arranged to cooperate with a thread of the needle.

[0045] Preferably, the needle thread is located on an external wall of the needle.

[0046] Preferably, a diameter of the needle varies along the longitudinal axis. Preferably, a portion of the needle, called proximal, intended to translate in the part arranged to exert pressure on the compression ring has a diameter greater than a diameter of a portion of the needle, called distal, intended to translate in the anti-extrusion ring, the sealing ring and the compression ring.

[0047] Preferably, the diameter of the hollow cylinder varies along the longitudinal axis. The portion of the hollow cylinder in which the proximal portion of the needle is intended to translate may have a diameter greater than a diameter of a portion of the hollow cylinder in which the distal portion of the needle is intended to translate.

[0048] Preferably, the needle is arranged to be mounted or adjusted or fitted tightly or clamped within the hollow cylinder.

[0049] Preferably, a first portion of the compression ring and a first portion of the part arranged to exert pressure on the compression ring are included in a first housing and a wall of the first housing comprises a thread arranged to cooperate with a thread of the part arranged to exert pressure on the compression ring.

[0050] Preferably, all or part of the first part of the compression ring and / or the first part of the part arranged to exert pressure on the compression ring are arranged to be mounted or adjusted or adjusted tightly or clamped in the first housing.

[0051] Preferably, the wall of the first housing is an inner wall of the housing. Preferably, the thread of the part arranged to exert pressure on the compression ring is provided on an outer wall of the part arranged to exert pressure on the compression ring. Preferably, the anti-extrusion ring, the sealing ring and a second part of the compression ring are included in a second housing adjoining the first housing.

[0052] Preferably, the anti-extrusion ring and / or the sealing ring and / or the second part of the compression ring are arranged to be mounted or adjusted or adjusted tightly or clamped in the second housing.

[0053] Preferably, at least a portion or all, more preferably only a portion, of the second part of the compression ring is included in the second housing.

[0054] Preferably, the first and second housings communicate. Preferably, the first housing is located upstream of the second housing relative to the closure direction x'x.

[0055] Preferably, the throttle valve comprises a geared motor, the geared motor comprises a shaft constituting the element capable of translating the needle, the shaft being coupled to the second end of the needle.

[0056] Preferably, the geared motor comprises a motor, preferably an electric motor, and a reducer.

[0057] According to the invention, a device for thermodynamic characterization of a fluid is also proposed, comprising:

[0058] - a compression chamber intended to receive the fluid,

[0059] - a piston mounted to slide in the compression chamber so as to be able to modify the volume of the compression chamber,

[0060] - a receiving chamber communicating with the compression chamber via the conduit, and

[0061] - the throttle valve, according to the invention, arranged to regulate a leakage rate of the fluid intended to circulate in the conduit.

[0062] Preferably, the first and second housings are provided in a wall of the compression chamber.

[0063] Preferably, the anti-extrusion ring of the throttle valve is hermetically mounted on the conduit. Preferably, the conduit comprises the orifice formed in the wall of the proximal portion of the conduit and the distal portion of the conduit is located upstream of the proximal portion of the conduit relative to the direction connecting the compression chamber to the receiving chamber.

[0064] Preferably, the first end of the needle of the throttle valve is arranged to translate, along the axis of revolution of the proximal portion of the conduit, in said proximal portion of the conduit. Preferably, the orifice is arranged to be closed or released by translation of the first end of the needle in the proximal portion of the conduit.

[0065] Preferably, the wall of the proximal portion of the conduit in which the orifice is formed is a side wall of the conduit, relative to the axis of revolution of the conduit.

[0066] Preferably, the axis of revolution of the conduit coincides with the longitudinal axis of the needle.

[0067] Preferably, the proximal portion of the conduit communicates with a junction through the orifice. Preferably, the junction is located downstream of the proximal portion, and the distal portion, of the conduit relative to the direction connecting the compression chamber to the receiving chamber. Preferably, the junction communicates with the receiving chamber.

[0068] Preferably, the proximal portion of the conduit communicates with the compression chamber through the distal portion of the conduit.

[0069] Preferably, the axis of revolution of the orifice forms an angle of between 40 and 50° relative to the axis of revolution of the proximal portion.

[0070] Preferably, the throttle valve according to the invention is suitable, more preferably is particularly suitable, more preferably is designed and particularly advantageously is specially designed, for the device for thermodynamic characterization of a fluid according to the invention.

[0071] Any characteristic of the throttle valve according to the invention can be directly transposed to the device for thermodynamic characterization of a fluid according to the invention and vice versa. Description of the figures

[0072] Other advantages and particularities of the invention will appear on reading the detailed description of implementations and embodiments which are in no way limiting, and the following appended drawings:

[0073] [Fig. 1] FIGURE 1 is a schematic representation of a longitudinal sectional view of a throttle valve,

[0074] [Fig. 2] FIGURE 2 is a schematic representation of a sectional view of the throttle valve coupled to a geared motor and mounted on the compression chamber of the device for thermodynamic characterization of a fluid, the sectional plane is perpendicular to the longitudinal axis of the piston and to the longitudinal axis of the pressure chamber,

[0075] [Fig. 3] the left part of FIGURE 3 is a schematic representation of a sectional view of the throttling valve coupled to a geared motor and mounted on the compression chamber of the device for thermodynamic characterization of a fluid, the sectional plane is perpendicular to the longitudinal axis of the piston and to the longitudinal axis of the pressure chamber, FIGURE 3 is an enlargement of FIGURE 2 centered on a part of the compression chamber and on the throttling valve,

[0076] [Fig. 4] FIGURE 4 is a schematic representation of a sectional view of the device for thermodynamic characterization of a fluid centered on the piston and the compression chamber, the sectional plane includes the longitudinal axis of the piston and the longitudinal axis of the pressure chamber.

[0077] Description of the embodiments

[0078] The embodiments described below being in no way limiting, it will be possible in particular to consider variants of the invention comprising only a selection of the described characteristics, isolated from the other described characteristics (even if this selection is isolated within a sentence comprising these other characteristics), if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection comprises at least one characteristic, preferably functional without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0079] With reference to FIGURES 1 to 3, an embodiment of the throttle valve 1 according to the invention is described.

[0080] Referring to FIGURE 1, the throttle valve 1 comprises a stack 7 formed of an anti-extrusion ring 71, a sealing ring 72, a compression ring 73 and a part 74 arranged to exert pressure on the compression ring 73. The compression ring 73 compresses the sealing ring 72 in the opening direction xx'. Each of the elements 71, 72, 73, 74 of the stack 7 comprises a through bore along the longitudinal axis 9. The through bores of the elements 71, 72, 73, 74 of the stack 7 constitute the hollow cylinder 75.

[0081] The anti-extrusion ring 71 is made of a hard material, for example stainless steel or steel. The anti-extrusion ring 71 prevents the sealing ring 72 from extruding out of the hollow cylinder 75. In particular, the anti-extrusion ring 71 prevents the sealing ring 72 from extruding out of the hollow cylinder 75 into the conduit 4 in the closure direction x'x. The sealing ring 72 is made of a deformable material, for example Teflon. The sealing ring 72 prevents fluids from the conduit 4 from passing in the opening direction xx'. The part 74 arranged to exert pressure on the compression ring 73 is a nut 74 according to the non-limiting embodiment. A portion of the wall of the first housing 81 comprises a thread 13 arranged to cooperate with a thread 12 provided on the external wall of the nut 74.Thus, the threaded portion 12 of the nut 74 is screwed into the first housing 81 so that the nut 74 exerts continuous pressure on the compression ring 73. The compression ring 73 compresses and deforms the sealing ring 72 in the second housing 82. The sealing ring 72 in turn compresses the anti-extrusion ring 71 against the end wall of the second housing 82. The compression ring 73 is made of bronze according to the non-limiting embodiment. The choice of the torque formed by the compression ring 73 and the part 74 arranged to exert pressure on the compression ring 73 is made so as to have a low coefficient of friction. Thus, the compression of the stack 7 in the first and second housings is optimized.

[0082] The anti-extrusion rings 71 and sealing rings 72 are included in the second housing 82. A first part 731 of the compression ring 73 and a first part 741 of the nut 74 are included in the first housing 81. A second part 732 of the compression ring 73 is included in the second housing 82. A second part 742 (the head 742) of the nut 74 is included in a third housing 83. The third housing 83 is adjacent to the first housing 81 and located upstream of the first housing 81 relative to the closure direction x'x. The first housing 81 is adjacent to the second housing 82 and located upstream of the second housing 82 relative to the closure direction x'x.The external diameter of the elements 71 and 72 and the external diameter of the parts 731, 732 and 741 of the elements 73 and 74 being adjusted to the internal diameter of their respective housing 81, 82, the nut 74 makes it possible to position the elements in their housing when mounting the stack 7 in the housings 81, 82.

[0083] The throttle valve 1 comprises a needle 2 arranged to translate along the longitudinal axis 9 of the needle 2. The needle 2 is arranged to translate in the hollow cylinder 75. The first end 3 of the needle 2 is arranged to translate, along the axis of revolution 9, in the proximal portion 41 of the conduit 4. The first end 3 of the needle is also arranged to translate in the part of the hollow cylinder 75 included in the second housing 82. According to the non-limiting embodiment, the conduit 4 comprises an orifice 11 formed in the side wall of the proximal portion 41 of the conduit. The conduit 4 also comprises a distal portion 42 which is located upstream of the proximal portion 41 of the conduit relative to the opening direction xx'. The translation of the needle 2 in the closure direction x'x causes the conduit 4 to be closed by the first end 3 of the needle 2.No fluid flows in the conduit 4 when the apex 3 of the needle 2 is in the closed position. In this closed position, the apex 3 is inserted into the distal portion 42 of the conduit 4 and obstructs the conduit 4. The translation of the needle 2, and therefore of the apex 3 of the needle 2, in the opening direction xx' causes the release (or opening) of the distal portion 42 of the conduit 4.

[0084] The needle 2 has a second end 5 located upstream of the hollow cylinder 75 relative to the closure direction x'x. The second end 5 of the needle 2 is intended to be coupled with an element 6 capable of putting the needle 2 into translation.

[0085] Such an arrangement of the throttle valve 1 makes it possible to precisely regulate the leakage rate of the fluid circulating in the conduit 4, having pressures of several hundred bars.

[0086] Depending on the applications, the conduit 4 may or may not be part of the throttle valve 1. In some applications, the throttle valve 1 may be intended to be hermetically mounted on the conduit 4 of an existing device. In other applications, the throttle valve 1 may include the conduit 4 and form a single unit with the conduit 4.

[0087] When high precision in regulating the leakage rate of the fluid in the conduit 4 is required, it is advantageous for the needle 2 to be arranged to translate in the hollow cylinder 75 in a translation-rotational movement. In this case, the element 6 with which the needle 2 is intended to be coupled is capable of putting the needle 2 into translation-rotational movement.

[0088] In the case where a high degree of precision in regulating the leakage rate of the fluid in the conduit 4 is required, it is also advantageous for the bore of the nut 74, and therefore the internal wall of the nut 74, to comprise a thread arranged to cooperate with a thread provided on the external wall of the needle 2.

[0089] Still in the case where a high precision of the regulation of the leakage rate of the fluid in the conduit 4 is required, it is also advantageous for the external diameter of the needle 2 to vary according to the longitudinal direction 9. The portion 21 of the needle 2 intended to translate in the nut 74 has a diameter dl greater than the diameter d2 of the portion 22 of the needle 2 intended to translate in the anti-extrusion ring 71, the sealing ring 72 and in the compression ring 73. The diameter d2 of the portion 21 of the needle 2 is greater than the diameter dl of the portion 22 of the needle 2. This has the effect of facilitating the coupling between the needle 2 and the element 6 with which the needle 2 is intended to be coupled. This also has the effect of reducing the stress exerted on the needle 2 by the element 6, during the translation of the needle 2, during the transmission of the torque by the element 6 on the needle 2.

[0090] Also, with reference to FIGURE 2, it is advantageous for the throttle valve 1 to comprise a geared motor 10. The geared motor 10 comprises a shaft 6 constituting the element 6 capable of translating the needle 2. The shaft 6 is coupled to the second end 5 of the needle 2. Advantageously, the shaft 6 of the geared motor 10 is arranged to translate-rotate the needle 2. In practice, the geared motor 10 comprises an electric motor 102 and a reduction gear 101. The reduction gear 101 drives the shaft 6 to which the second end 5 of the needle 2 is coupled. In the case where a high degree of precision in regulating the leak rate in the conduit 4 is required, it is further advantageous for the translation of the needle 2 to be finely controlled in order to precisely regulate the leak rate of the fluid in the conduit 4. Also, the coupling between the needle 2 and the element putting the needle 2 into translation must be rigid and mechanical play avoided.Also, a coupling part 14 ensures the transmission of the movement of the shaft 6 to the needle 2. The coupling part 14 is mounted on the shaft 6 at one of its ends and on the needle 2 at the other of its ends. According to the non-limiting embodiment, the coupling between the coupling part 14 and the needle 2 is of the slide type.

[0091] With reference to FIGURES 2 to 4, a device 15 for thermodynamic characterization of a fluid is presented, referred to as device 15 in the remainder of the description. According to the non-limiting embodiment, the device 15 is intended and arranged to characterize fluids taken from the subsoil, in particular an oil, for example petroleum.

[0092] The device 15 comprises the throttle valve 1, according to the invention, which is arranged to regulate a leak rate in the conduit 4. The device 15 comprises a compression chamber 16 intended to receive the fluid, a piston 17 slidably mounted in the compression chamber 16. The volume of the compression chamber 16 is modified by translation of the piston 17 in the compression chamber 16. The device 15 also comprises a receiving chamber, which is a gasometer according to the embodiment. The gasometer communicates with the compression chamber 16 through the conduit 4. The piston 17 translates in the compression chamber 16 along its longitudinal axis 23 which coincides with the longitudinal axis 23 of the compression chamber 16. The longitudinal axis 23 of the piston 17 also constitutes an axis of revolution 23 of the piston 17 and of the compression chamber 16.

[0093] The leakage rate of the fluid circulating in the conduit 4 corresponds to a flow rate of the fluid circulating in the conduit 4. According to the embodiment, it is not sought to know or determine the flow rate of fluid in the conduit 4 because the value of the flow rate of the fluid through the conduit is of no interest in the context of the process of regulating the pressure in the compression chamber 16.

[0094] According to the embodiment, the device 15 comprises the conduit 4. The throttle valve 1 is hermetically mounted on the conduit 4. The distal portion 42 of the conduit 4 connects the compression chamber 16 to the proximal portion 41 of the conduit 4. An opening is provided in the bore 19, in other words in the internal wall 19, of the compression chamber 16. The opening connects the distal portion 42 of the conduit 4 to the compression chamber 16. The orifice 11 connects the proximal portion 41 of the conduit 4 to a conduit (not shown). The conduit connects the orifice 11 to the gasometer. In order to limit dead volumes as much as possible, the conduit and the conduit 4 have reduced sizes, typically 0.5 mm in diameter and 1.7 mm in length. The axis of revolution of the orifice 11 forms an angle of between 40 and 50° relative to the axis of revolution 9 of the proximal portion 42.

[0095] According to the embodiment, the first housing 81, the second housing 82 and the third housing 83 are provided in the wall 20 of the compression chamber 16.

[0096] Advantageously, the device 15 comprises a sensor 18 arranged to measure the pressure in the compression chamber 16. According to the embodiment, and advantageously, the sensor 18 is housed in the piston 17 so as to have a surface which is flush with the surface 171 of the piston 17. In a non-limiting manner, the sensor 18 is equipped with instruments including a strain gauge (not shown) and a platinum resistance probe (not shown) intended to measure the pressure and temperature of the fluid in the compression chamber 16.

[0097] According to the non-limiting embodiment, and with reference to FIGURE 3, the device comprises a throttling valve 1. In FIGURE 3, the throttling valve denoted 1 is visible. The throttling valve 1 ensures the regulation of the pressure in the compression chamber 16. In a non-limiting manner, the device 15 comprises means arranged so that the fluid to be studied is injected into the compression chamber 16. In a non-limiting manner, the device 15 may comprise vents arranged to fill or vent the compression chamber 16 and / or the gasometer once the process is complete.

[0098] In a manner known per se, the device 15 comprises other members, not shown, including in a non-limiting manner:

[0099] - a system for heating the fluid contained in the compression chamber 16, and / or

[0100] - a porthole to allow viewing of the interior of the compression chamber 16, and / or

[0101] - a high-definition camera for studying phase changes and / or sedimentations of the fluid contained in the compression chamber 16, and / or

[0102] - a system for stirring the fluid contained in the compression chamber 16, for example by electromagnetic vibrations, and / or

[0103] - a system for cooling the fluid contained in the compression chamber 16.

[0104] In operation, the piston 17 compresses the sampled fluid, which is at ambient pressure and temperature before compression, until the pressure conditions under which it was stored in the subsoil are reproduced. Once under pressure, the fluid is decompressed which causes degassing of the fluid at a certain pressure. The gas is the first phase evacuated from the compression chamber 16 through the conduit 4. The pressure in the compression chamber 16 is kept constant during the evacuation of the gas. Advantageously, a control loop makes it possible to maintain the constant pressure in the compression chamber 16 by controlling the opening and closing of the throttling valve 1 as a function of the pressure measured in the compression chamber 1 by the sensor 18.A setpoint, in gas flow, is sent to the piston 17 which causes a movement at constant speed of the piston 17, the throttling valve 1 ensures the evacuation of the gas, in the gasometer, out of the compression chamber 16, so as to maintain the constant pressure in the compression chamber 16. Before evacuation of the gas, the gasometer is placed under vacuum. The quantity of gas recovered is measured and its value must be known precisely. Also, in addition to allowing a high precision in the regulation of the gas leak rate in the conduit 4, the device 15 and the throttling valve 1 according to the invention also make it possible to obtain a high precision in the measurement of the volume of gas recovered in the gasometer. For this purpose, and advantageously, the size of the conduit 4 is reduced. The arrangement of the throttling valve 1 as described above makes it possible to considerably reduce measurement errors for small volumes of gas.Indeed, this arrangement makes it possible to obtain a compact, small-sized throttle valve 1, which is nevertheless resistant to and capable of working with significant pressure differentials. Typically pressures of around 1000 bars and a minimum pressure differential of around 1.10. 4 , typically 1.10 5, between the upstream part, the compression chamber 16 in the case of the device 15, and the downstream part, the gasometer in the case of the device 15, of the conduit 2 are obtained. According to the non-limiting embodiment, the diameter d2 of the portion 22 of the needle 2 is 1 millimeter. The diameter of the portion 21 of the post 2 is 2.5 millimeters (mm). The length, along the longitudinal direction 9 of the needle 2 is 25.3 mm. The diameter of the proximal portion 41 of the conduit 4 is 1.2 mm and the diameter of the distal portion 42 of the conduit 4 is 0.5 mm. The length of the proximal portion 41 of the conduit 4, along the longitudinal axis, is 2 mm and the length of the distal portion 42 of the conduit 4, along the longitudinal axis, is 1.7 mm.

[0105] In addition to enabling work on small volumes of gas, and therefore reducing errors in measuring gas volumes, such an arrangement also makes it possible to significantly limit the size of the throttle valve 1 and the device 15.

[0106] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention, in particular by means of variants which can be combined with each other of the embodiments previously described.

[0107] Furthermore, the various features, forms, variations and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

Claims

CLAIMS 1. Throttling valve (1) comprising: - a needle (2) arranged to translate, along a longitudinal axis (9) of the needle, in a hollow cylinder (75) so that a first end (3) of the needle closes or releases a conduit (4) located downstream of the hollow cylinder relative to a direction (x'x), called the closing direction, connecting a second end (5) of the needle to the first end of the needle, the second end of the needle is: • located upstream of the hollow cylinder relative to the closure direction (x'x), and • intended to be coupled with an element (6) capable of putting the needle into translation so as to regulate a leakage rate of a fluid intended to circulate in the conduit, - a stack (7) comprising, in a direction (xx'), called the opening direction, connecting the first end of the needle to the second end of the needle, an anti-extrusion ring (71), a sealing ring (72), a compression ring (73) and a part (74) arranged to exert pressure on the compression ring so that said compression ring compresses the sealing ring, each of the elements of the stack comprises a through bore, the through bores of the elements of the stack constitute the hollow cylinder.

2. Valve (1) according to claim 1, in which the needle (2) is arranged to translate in the hollow cylinder (75) according to a translation-rotation movement, the element (6) with which the needle is intended to be coupled being capable of putting the needle into translation-rotation movement.

3. Valve (1) according to the preceding claim, in which the bore of the part (74) arranged to exert pressure on the compression ring (73) comprises a thread arranged to cooperate with a thread of the needle (2).

4. Valve (1) according to any one of the preceding claims, in which a diameter of the needle (2) varies according to the longitudinal direction (9), a portion (21) of the needle intended to translate in the part (74) arranged to exert pressure on the compression ring (73) has a diameter greater than a diameter of a portion (22) of the needle intended to translate in the anti-extrusion ring (71), the sealing ring (72) and the compression ring.

5. Valve (1) according to any one of the preceding claims, in which a first part (731) of the compression ring (73) and a first part (741) of the part (74) arranged to exert pressure on the compression ring compression are included in a first housing (81) and a wall of the first housing comprises a thread arranged to cooperate with a thread of the part arranged to exert pressure on the compression ring.

6. Valve (1) according to the preceding claim, in which the anti-extrusion ring (71), the sealing ring (72) and a second part (732) of the compression ring (73) are included in a second housing (82) adjoining the first housing (81).

7. Valve (1) according to any one of the preceding claims, comprising a geared motor (10), the geared motor comprises a shaft (6) constituting the element (6) capable of rotating-translating the needle (2), the shaft being coupled to the second end (5) of the needle.

8. Device for thermodynamic characterization of a fluid, comprising a compression chamber intended to receive the fluid, a piston mounted to slide in the compression chamber so as to be able to modify the volume of the compression chamber, a receiving chamber communicating with the compression chamber by a conduit (4) and a throttling valve (1), in accordance with one of claims 1 to 7, arranged to regulate the leakage rate of the fluid intended to circulate in the conduit.

9. Device according to claim 8, in which an anti-extrusion ring (71) of the throttle valve (1) is hermetically mounted on the conduit (4).

10. Device according to claim 8 or 9, in which: - the conduit (4) comprises: • an orifice (11) formed in a wall of a portion (41) of the conduit, called the proximal portion, and • a portion (42), called the distal portion, located upstream of the proximal portion of the conduit relative to the direction connecting the compression chamber to the receiving chamber, - a first end (3) of a needle (2) of the throttle valve (1) is arranged to translate, along an axis of revolution (9) of the proximal portion of the conduit, in said proximal portion of the conduit; the orifice is arranged to be closed or released by translation of the first end of the needle in the proximal portion of the conduit.

11. Device according to the preceding claim, in which: -the proximal portion (41) of the conduit (4) communicates with a junction via the orifice (11); the junction is located downstream of the proximal portion of the conduit by report to the direction connecting the compression chamber to the receiving chamber and communicates with the receiving chamber, - the proximal portion of the conduit communicates with the compression chamber via the distal portion (42) of the conduit.

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