Fluid circulator, device and method for withdrawing a fluid from a pipe

Abstract

The invention relates to a fluid circulator (6), in particular for use in a device and a method for withdrawing a fluid from a pipe and reinjecting a fluid into a pipe, the fluid circulator (6) comprising a cylinder (29) and a ferromagnetic piston (25), the cylinder (29) defining an inlet chamber (50) and an outlet chamber (51) separated by the piston (25). The cylinder (29) comprises a fluid inlet (28) and a fluid outlet (30). It further comprises a first check valve (32) in the piston (25) and a second check valve (22) at the fluid outlet (30). Moreover, the circulator (6) comprises at least one electromagnet (24, 26) for driving the piston (25) in translation and each of the inlet chamber (50) and the outlet chamber (51) comprises a spring (27, 21) attached to a longitudinal end of the cylinder (29) and to the piston (25).

Description

[0001] FLUID CIRCULATOR, DEVICE AND METHOD FOR TAKING A FLUID FROM A PIPELINE

[0002] Technical field

[0003] The invention relates to a fluid circulator and a device and method for sampling and reinjecting a fluid, such as a gas, into a pipe, comprising the fluid circulator, in particular for carrying out an analysis of the fluid in the pipe.

[0004] Gas network managers must ensure the quality of the gas they use, whether this gas comes from conventional gas (high-flow, low- or high-pressure vein) or from secondary veins from the production of renewable gas (low-flow, low- or high-pressure vein), such as biomethane.

[0005] The development of renewable gas production is expanding rapidly. The Energy Transition for Green Growth Act No. 2015-992 of August 17, 2015, sets a target of 10% renewable gas in traditional networks by 2030.

[0006] Each of these renewable gas production sites has a Shelter (or "shelter") to house the gas odorization system as well as the gas chromatograph analyzers to control the composition of the gas and its odorization rate, which must comply with regulatory constraints. Currently, the Shelters are installed at varying distances from the gas transmission network pipe, between 20 and 100 meters, and the chromatographs are supplied with gas to be analyzed by a small diameter line, tapped directly into the gas transmission network pipe. This bypass loop is open, which means that it analyzes the gas and releases the excess gas, not used by the analyzers, as well as the gas leaving these analyzers, to the atmosphere.

[0007] Gas industry players have recently become aware of the environmental impact of these gas releases, particularly when the gas is methane, whose impact on the ozone layer is worse than carbon dioxide.

[0008] Prior art

[0009] Figure 1 illustrates a system for sampling a gas, methane, according to the prior art. Gas is transported in a pipe 1 to the gas transmission network. To be allowed to be introduced into the gas transmission network, the gas must meet specific criteria defined either by the regulations or by the operator of the gas transmission network.

[0010] To do this, the gas conveyed in the pipe can be treated upstream to achieve a sufficient purity level, sufficient odorization (THT content for TetraHydroThiophene), a humidity level below a certain value for example. In order to verify that the gas in the pipe meets these different parameters, gas is sampled from within the pipe by a sampling probe 2 then is conveyed by a conduit 3 to an analysis system 4 allowing one or more measurements. The analysis system 4 can include several analysis means to carry out different measurements (humidity, THT content for odorization for example). Then, the gas is released into the atmosphere through a vent 5. The system can also include several other vents (not shown).

[0011] Thus, the gas sampling loop in Figure 1 is open and terminates at vent 5.

[0012] For environmental reasons, releasing gas, particularly methane, into the atmosphere is no longer an option, particularly because of its effects on the ozone layer.

[0013] Figure 1 shows the case of a gas pipe but of course, another fluid, such as a liquid, a supercritical gas, a multiphase fluid including or not solid particles could replace the gas and the release of this fluid into the environment is, for the same reasons, problematic or even harmful to the environment.

[0014] To avoid this release into the atmosphere of the fluid contained in the pipe, re-injection of the fluid, after analysis, into the pipe is one of the solutions sought. However, this re-injection is complex, in particular for the following reasons:

[0015] The speed of circulation of the fluid in the pipe is high, up to several meters per second approximately, to ensure a time between sampling and reinjection of the gas less than a predetermined duration. By respecting this predetermined duration, it can be ensured that if the fluid analyzed is non-compliant, this fluid can be isolated from the gas transport network thanks to an isolation valve located downstream of the pipe, the predetermined duration depending on the fluid flow rate in the pipe, the diameter of the pipe and the distance downstream of the isolation valve from the sampling and reinjection;

[0016] Fluid pressure for fluid reinjection and pressure losses induced in the pipes;

[0017] The energy consumption required for reinjection which can be high due to the circulation speed, pressure and continuous operation;

[0018] The reliability over time of such a system;

[0019] Safety aspects in ATEX (Explosive Atmosphere) zones;

[0020] Low traffic flow rates.

[0021] To ensure the reinjection of the fluid, we know in particular the patent application EP 3,919,839 which relates to a system for sampling and reinjecting a fluid into a circuit. To ensure the reinjection of the fluid, the system here comprises a pump. The use of a pump (or a compressor) envisaged as a circulator requires a very high rotation speed, of the order of 15,000 to 20,000 revolutions per minute to ensure the circulation speed of the fluid. This rotation speed, in continuous operation, risks reducing the life of the pump or causing malfunctions. In the event of a malfunction, the distribution of the fluid, biomethane in particular, would have to be interrupted and the fluid stored elsewhere. In addition, such a pump or compressor requires very high energy consumption.

[0022] To reinject the fluid into the pipe, the invention consists of proposing a fluid circulator making it possible both to reach the circulation speed of the fluid to ensure a time between sampling and reinjection less than the predetermined duration, continuously, while ensuring the pressure necessary for reinjection, or even to compress the fluid if necessary, while limiting energy consumption and ensuring reliability over time.

[0023] Summary of the invention

[0024] The objective of the invention is therefore to limit or even eliminate the discharge of the collected fluid by reinjecting it into the pipe and thus introducing it into the fluid transport network, i.e. by creating a closed loop.

[0025] To this end, the invention consists of proposing a fluid circulator, in particular a gas circulator, ensuring reliability of the system over time in continuous operation and ensuring a predetermined fluid circulation speed, for example between 0.1 m / s and 2 m / s, while limiting energy consumption.

[0026] The invention relates to a fluid circulator, preferably a gas circulator, comprising a cylinder and a ferromagnetic piston capable of moving longitudinally in the cylinder, along the axis of the cylinder, the cylinder delimiting an inlet chamber and an outlet chamber separated by the piston, the cylinder comprising a fluid inlet connected to the inlet chamber and a fluid outlet connected to the outlet chamber, the circulator comprising a first non-return valve in the piston configured to open when the piston moves towards the inlet chamber so as to allow the passage of fluid from the inlet chamber to the outlet chamber and a second non-return valve positioned at said fluid outlet, the second non-return valve being configured to open when the piston moves towards the outlet chamber, to allow the fluid to exit the circulator.In addition, the circulator comprises at least one electromagnet for directly driving the piston in translation in a reciprocating motion in the cylinder, at least one electromagnet being arranged around the cylinder, and each of the inlet and outlet chambers comprises a spring attached on the one hand to a longitudinal end of the cylinder and on the other hand to the piston. Preferably, the circulator comprises two electromagnets arranged around the cylinder, one of the two electromagnets being configured to move the piston in one direction, the other of the two electromagnets being configured to move the piston in the other direction, preferably the two electromagnets being arranged longitudinally, along the longitudinal axis of the cylinder, one behind the other.

[0027] Advantageously, the circulator comprises a third non-return valve at the fluid inlet for introducing fluid into the inlet chamber, the third non-return valve being configured to open when the piston moves toward the outlet chamber.

[0028] According to one configuration of the invention, the first non-return valve, the second non-return valve and / or the third non-return valve comprises a spring for increasing the value of the opening pressure by a predetermined value.

[0029] The invention also relates to a device for sampling and re-injecting a fluid into a pipe, comprising a bypass line for diverting at least part of the fluid from the pipe, the bypass line comprising a means for sampling the fluid from the pipe to introduce the sampled fluid into the bypass line and a means for re-injecting the fluid into the pipe, the bypass line comprising a fluid circulator as described previously in the bypass line.

[0030] Preferably, the bypass line comprises at least one fluid analysis system downstream of the fluid sampling means, in the direction of circulation of the fluid in the fluid sampling and reinjection device, in particular upstream of the circulator, preferably, the analysis system comprises at least one analysis means, such as a chromatograph.

[0031] Advantageously, the bypass line comprises equipment comprising a fluid exhaust channel, and / or the analysis system and / or at least one analysis means comprises a fluid exhaust conduit.

[0032] According to a variant of the invention, at least one exhaust channel and / or at least one exhaust duct, preferably all the exhaust channels and all the exhaust ducts, are fluidically connected to a reservoir, the reservoir being positioned on the bypass line, upstream of the fluid circulator.

[0033] According to one configuration of the invention, the bypass line comprises a means for expanding the fluid between the sampling means and the analysis system, the fluid circulator then being configured to recompress the fluid to a pressure substantially equal to the pressure of the pipe.

[0034] Preferably, the reinjection means and the sampling means are the same and unique equipment which allows the sampling and reinjection of the fluid into the pipe or the reinjection means is positioned upstream or downstream of the sampling means on the pipe, in the direction of circulation of the fluid in the pipe. The invention also relates to a method for sampling and reinjecting fluid from the sampling and reinjection device as described above, for which at least the following steps are carried out:

[0035] - a fluid is taken from a pipe, by the sampling means, to introduce it into a bypass line;

[0036] - preferably, the sampled fluid is analyzed to determine its chemical composition or its content of certain compounds, the compounds preferably comprising THT, H2S, H2O and / or PCS;

[0037] - the fluid is circulated in the circulator to convey the fluid to the reinjection means; and

[0038] - the sampled fluid is reintroduced into the pipe using the reinjection means, positioned upstream, downstream or at the level of the sampling means.

[0039] List of figures

[0040] Other characteristics and advantages of the circulator, the device and / or the method according to the invention will appear on reading the following description of non-limiting examples of embodiments, with reference to the figures appended and described below.

[0041] Figure 1 represents a gas sampling system, without gas reinjection, according to the prior art.

[0042] Figure 2 represents a first embodiment of a fluid sampling and reinjection device according to the invention.

[0043] Figure 3 represents a second embodiment of a fluid sampling and reinjection device according to the invention.

[0044] Figure 4 represents a third embodiment of a fluid sampling and reinjection device according to the invention.

[0045] Figure 5 represents a fourth embodiment of a fluid sampling and reinjection device according to the invention.

[0046] Figure 6 shows a fluid circulator according to the invention, when the piston moves towards the inlet chamber. Figure 7 shows the circulator of Figure 6 according to the invention, when the piston moves towards the outlet chamber.

[0047] Description of the embodiments

[0048] The invention relates to a fluid circulator and a device for sampling and reinjecting a fluid into a pipe. The fluid may advantageously be a gas, in gaseous or supercritical form, and the pipe may advantageously be a pipe of a gas transport network.

[0049] The gas can be methane (fossil gas) and more particularly biomethane (renewable gas).

[0050] Renewable gas means gas that is not extracted from fossil reserves.

[0051] Biogas means a gas obtained by the fermentation of animal or plant organic matter.

[0052] Biomethane means methane obtained by processing biogas (from which moisture, CO2 and other impurities are removed).

[0053] The fluid circulator (or circulation means) according to the invention comprises a cylinder and a ferromagnetic piston capable of moving longitudinally in the cylinder, along the axis of the cylinder. In addition, the cylinder delimits an inlet chamber and an outlet chamber separated by the piston. In other words, the inlet chamber is delimited on the one hand by a part of the cylinder and by a surface of the piston and the outlet chamber is delimited on the other hand by another part of the cylinder and by another surface of the piston. The inlet and outlet chambers are formed by volumes inside the cylinder. The cylinder comprises a longitudinal inlet end (delimiting one end of the inlet chamber) and a longitudinal outlet end (delimiting one end of the outlet chamber).As the piston moves longitudinally in the cylinder, the volumes of the inlet and outlet chambers vary over time, and as the volume of one chamber increases, the other decreases. In addition, the cylinder includes a fluid inlet connected to the inlet chamber; preferably, the inlet is positioned on the cylinder axis and on the longitudinal inlet end of the cylinder. The cylinder also includes a fluid outlet connected to the outlet chamber; preferably, the outlet is positioned on the cylinder axis and on the longitudinal outlet end of the cylinder. Thus, fluid enters the circulator through the fluid inlet and exits the circulator through the fluid outlet.Furthermore, the circulator also comprises a first check valve in the piston and this first check valve is configured to open when the piston moves towards the inlet chamber (towards the longitudinal inlet end of the cylinder) so as to allow the passage of the fluid from the inlet chamber to the outlet chamber, and a second check valve positioned at the outlet of the fluid, the second valve being configured to open when the piston moves towards the outlet chamber (towards the longitudinal outlet end of the cylinder), to let the fluid exit the circulator. Thus, the circulator is intended to circulate the fluid in one direction only.The first valve may preferably be configured to close when the piston moves towards the outlet chamber and the second valve may preferably be configured to close when the piston moves towards the inlet chamber, so as to facilitate the circulation of the fluid and to generate a possible back pressure predetermined by the first and second non-return valves. According to the invention, the circulator comprises at least one electromagnet for driving the piston (made of ferromagnetic material) in translation in a reciprocating motion in the cylinder.

[0054] By back and forth movement, we mean a back and forth translational movement, that is to say a translational movement of successively alternating direction (in one direction then in the opposite direction).

[0055] This translational movement is generated directly by at least one electromagnet (preferably by two electromagnets), without transforming a rotational movement (generated by an electric motor for example) into translation, for example via a helical screw between the cylinder and the piston. By directly generating the longitudinal translation by at least one electromagnet, the movement is faster than if it were necessary to transform a generated rotational movement into translational movement. This makes it possible to achieve fluid circulation speeds of the order of 0.1 m / s and 2 m / s for example. When the circulator is intended to be used in a fluid sampling and reinjection device, this ensures that the time between the time the fluid is sampled and its analysis is less than a predetermined duration, for example the predetermined duration may be between 1 and 5 minutes.As a result, it is possible to avoid continuing to introduce a non-compliant gas into the network by actuating a valve downstream of the sampling point and the reinjection point before the analyzed gas reaches the network. In addition, the use of a piston in a cylinder is simple and robust. On the contrary, to achieve such fluid circulation speeds, the use of rotating parts, such as a compressor or a pump, would require very high rotation speeds (of the order of 15,000 to 20,000 revolutions per minute), the mechanical reliability of such a solution for continuous operation would not be guaranteed over time. In addition, when the fluid is a gas, it would then be necessary to have small clearances between the rotating parts and the fixed casing.The small clearance and high rotation speed may cause friction, heating, increase the clearance dimension over time (and therefore not ensure the circulation speed of the fluid over time) and increase the risk of malfunctions. In addition, using a rotating part such as a motor, driven by a shaft, would require the implementation of dynamic sealing means for very high rotation speeds, which on the one hand would increase the complexity of such a solution and on the other hand would increase the risk of malfunction. In addition, when the fluid is a gas, obtaining such a seal for high rotation speeds would not be sustainable over time, especially with continuous operation.

[0056] To drive the piston in longitudinal translation, at least one electromagnet is arranged around the cylinder (and the piston). If a single electromagnet is used, the polarity of the electromagnet can be reversed to reverse the direction of movement of the piston and thus allow back-and-forth movements of the piston in the cylinder.

[0057] According to the invention, each of the inlet and outlet chambers comprises a spring fixed on the one hand to a longitudinal end of the cylinder and on the other hand to the piston. Each of these springs serves both:

[0058] - A return spring to keep the piston at rest (none of the electromagnets being activated), in a neutral position, preferably approximately equidistant from each of the longitudinal inlet and outlet ends. Therefore, in this neutral rest position, the volume of the inlet chamber may be, for example, substantially equal to the volume of the outlet chamber.

[0059] - A shock absorber for the piston when it is driven into each of the two chambers. This shock absorber effect is particularly useful when the fluid is a gas because the shock absorber effect of the gas is then almost zero. This shock absorber effect helps to increase the life of the circulator.

[0060] According to a preferred embodiment of the invention, the circulator may comprise two electromagnets arranged around the cylinder (and the piston), one of the two electromagnets being configured to move the piston in one direction, the other of the two electromagnets being configured to move the piston in the other direction. Thus, when one of the electromagnets is activated, the piston moves longitudinally towards one of the chambers and when the other of the electromagnets is activated, the piston moves longitudinally towards the other chamber. When neither of the electromagnets is activated, the piston is in the rest position (neutral position), for example equidistant between the two longitudinal inlet and outlet ends of the cylinder. It is then returned to this rest position and is held there by the springs on either side of the piston.

[0061] Preferably, the two electromagnets can be arranged longitudinally, along the longitudinal axis of the cylinder, one behind the other. Thus, one of the electromagnets is more or less opposite the outlet chamber and the other of the electromagnets is more or less opposite the inlet chamber. The "more or less opposite" means that depending on the position of the piston, the inlet chamber and the outlet chamber are more or less large and therefore the "opposite" can be slightly modified depending on the position of the piston. This notion of opposite can be more easily understood in the rest position, where one of the electromagnets is then opposite one of the chambers and the other electromagnet is then opposite the other chamber.By positioning the electromagnets in this way, it is possible, by successive and alternating activation / deactivation of the electromagnets, to generate a longitudinal translational movement of the piston directly (without going through an intermediate rotational movement for example) by the electromagnets.

[0062] According to a preferred configuration of the invention, the circulator may comprise a third non-return valve at the fluid inlet for introducing the fluid into the inlet chamber, the third non-return valve being configured to open when the piston moves towards the outlet chamber (towards the longitudinal outlet end of the cylinder) and preferably to close when the piston moves towards the inlet chamber (towards the longitudinal inlet end of the cylinder). Thus, it is easier to circulate the fluid in the circulation means (i.e. the circulator) without driving the fluid punctually from the inlet chamber towards the inlet (in the opposite direction to what is desired) when the piston moves towards the inlet chamber.

[0063] Preferably, the first non-return valve, the second non-return valve and / or the possible third non-return valve may each comprise a return spring to increase the value of the opening pressure of the valve by a predetermined value. Thus, the opening of each valve can be better controlled and it is also possible to generate compression of the fluid in the circulator.

[0064] The invention also relates to a device for collecting and reinjecting fluid comprising:

[0065] - a bypass line for diverting at least part of the fluid from the pipe, the other part of the fluid remaining in the pipe to be transported for example to a position of use of the fluid via the gas transport network. The bypass line comprises: o a means for sampling the fluid in the pipe to introduce the sampled fluid into the bypass line. This sampling means may in particular be a sampling rod which makes it possible to sample a small part of the fluid circulating in the pipe, for example to analyze the chemical composition of this fluid; o a means for reinjecting the fluid into the pipe. This reinjection means thus makes it possible to reintroduce the fluid into the pipe, rather than releasing it into the atmosphere via the open bypass line of the prior art of Figure 1. This reinjection means may be an injector, a diffuser or a rod similar to the sampling rod.The use of this means of reinjection also makes it possible to avoid the use of a fluid storage tank in which the fluid could be stored rather than released into the atmosphere, this storage tank requiring a specific volume and management to "empty" the tank from time to time and avoid any unwanted increase in pressure, while avoiding the release of the fluid into the atmosphere. o A circulator as described previously.

[0066] The circulator ensures that the time between the time the fluid is sampled and its analysis is less than a predetermined duration, for example the predetermined duration can be between 1 and 5 minutes. It also allows the fluid pressure in the pipe to be reached, while limiting energy consumption.

[0067] Thanks to the invention, the fluid that was released into the atmosphere is collected and reintroduced into the pipe. As a result, atmospheric discharges are considerably reduced, or even eliminated. When the fluid is a greenhouse gas, such as carbon dioxide or methane, the invention has a very significant environmental impact.

[0068] When the fluid is not harmful to the environment, the invention nevertheless remains very relevant because it limits unnecessary overconsumption of the fluid.

[0069] Preferably, the bypass line may comprise at least one fluid analysis system downstream of the fluid sampling means, in the direction of circulation of the fluid in the fluid sampling and reinjection device (therefore in the direction of circulation of the fluid in the bypass line). This analysis system may in particular be used to analyze the composition of the fluid, its purity level, its humidity level or the presence of an undesired compound. The bypass line may be configured to ensure a time between the sampling of the fluid and its analysis in the analysis system of less than a predetermined duration, for example 2 minutes.This delay makes it possible to avoid the introduction of non-compliant gas into the fluid transport network, for example by closing a valve on the pipe downstream (in the direction of circulation of the fluid in the pipe) of the sampling point and the point of reinjection of the fluid into the pipe before the gas enters the network (downstream of the valve) or by using buffer tanks to delay the arrival of the gas in the network (to artificially increase the delay).

[0070] According to one configuration of the invention, the analysis system can be upstream of the circulator in order to be as close as possible to the sampling means. In addition, the analysis system can advantageously be positioned in a shelter in order to protect the analysis system equipment.

[0071] Alternatively, the analysis system may be downstream of the circulator. In addition, the analysis system may advantageously be positioned in a shelter to protect the analysis system equipment.

[0072] Advantageously, the analysis system may comprise at least one analysis means, such as a chromatograph or a micro-chromatograph or even a UV sensor (UV for Ultraviolet) measuring the particles present, and may possibly comprise several analysis means of the same technology or different technologies to measure the presence of different chemical species present in the fluid.

[0073] When the analysis system comprises several analysis means, these analysis means can be arranged in series or preferably in parallel. Indeed, by arranging the analysis means in parallel, it is possible to manage different volumes in the different analysis means, for example via flow control valves in each parallel branch leading to a different analysis means.

[0074] According to one configuration of the invention, the bypass line may comprise a means for expanding the fluid between the sampling means and the analysis system. Indeed, by limiting the pressure of the fluid in the bypass line, the volume of fluid circulating therein is limited. This may also allow a limitation of the pressure compatible with the analysis means(s) of the analysis system.

[0075] Preferably, the fluid circulator may be configured to recompress the fluid to a pressure substantially equal to the pipe pressure. As a result, it is not necessary to use another compression means, such as a compressor, to recompress the fluid before reinjecting it into the pipe, this compression means then being a significant energy consumer. Indeed, it is preferable for the fluid to be reinjected at substantially the same pressure as that of the pipe. To configure the circulator to compress the fluid, it is possible to use the following different factors, alone or in combination with each other:

[0076] - The power of the electromagnet(s). In fact, the more powerful the electromagnets are, the more they will allow the piston to compress the inlet chamber and / or the outlet chamber and therefore be able to generate an increase in pressure.

[0077] - The surface of the piston in contact with the fluid in the inlet chamber and in the outlet chamber. In fact, by inducing a difference between these surfaces, it is possible to compress the fluid. To reduce one of these surfaces, it is possible, for example, to add a central shaft fixed to the piston on one side, for example, on the outlet chamber side.

[0078] - To use return springs of varying strength for each check valve. In fact, using these return springs for each check valve allows the opening pressure of the valves to be modified.

[0079] According to an advantageous variant of the invention, the bypass line may comprise conduits between the different equipment (sampling means, analysis system, circulator, injection means and possibly others), the external diameter of all the conduits of the bypass line being able to be less than 2” (i.e. 50.8mm), preferably less than 1” (i.e. 25.4mm) and preferably less than or equal to 1 / 4” (or 6.35mm). By limiting the diameter of the pipes, the flow rate and therefore the volume of fluid sampled is limited. In the case of explosive gases, which is the case for methane (and therefore biomethane) in particular, the constraints linked to the ATEX environment, for “AT mosphère Explosive” are reduced. This is particularly advantageous when a shelter is used for the analysis system, among other things.

[0080] According to one configuration of the invention, the diameters of the conduits upstream and downstream of the circulator may be different.

[0081] Advantageously, the reinjection means and the sampling means can be a single piece of equipment that allows the sampling and reinjection of fluid into the pipe. This single piece of equipment can in particular be a sampling and injection rod. This makes it possible to reduce the number of pieces of equipment in the bypass line and their space requirement on the pipe.

[0082] Alternatively, the reinjection means can be positioned upstream or downstream of the sampling means on the pipe, in the direction of circulation of the fluid in the pipe. By positioning it downstream, the fluid can be reintroduced substantially at the level of the volume of gas from which it was sampled and a second sampling of the same gas is avoided. By positioning it upstream, for example, before the fluid treatment units, this fluid can be reprocessed. This can be advantageous when the sampled fluid is non-compliant.

[0083] According to one implementation of the invention, the bypass line may comprise equipment (each) comprising a fluid exhaust channel, and / or the analysis system and / or at least one analysis means may comprise a fluid exhaust conduit. This exhaust channel and this exhaust conduit make it possible to evacuate the analyzed fluid, for example. The equipment may be valves or valves, for example.

[0084] Preferably, at least one exhaust channel and / or at least one exhaust duct, preferably all exhaust channels and all exhaust ducts, are fluidically connected to a reservoir, the reservoir being positioned on the bypass line, upstream of the fluid circulator. By connecting the various fluid exhausts, the fluid that would be discharged to the atmosphere if the exhaust channel or exhaust duct were left open to the atmosphere is collected. If all exhaust channels and ducts are connected, all the fluid is collected in the reservoir instead of being discharged to the atmosphere. The reservoir then serves as a buffer unit and the fluid is then sent to the circulator to be reintroduced into the pipe.

[0085] The invention also relates to a method for sampling and re-injecting fluid from the sampling and re-injection device as described above, for which at least the following steps are carried out:

[0086] - a fluid is taken from a pipe, by the sampling means, to introduce it into a bypass line;

[0087] - preferably, the sampled fluid is analyzed to determine its chemical composition or its content of certain compounds, the compounds preferably comprising THT (TetraHydroThiophene), H2S (Dihydrogen Sulfide), H2O (water) and / or the higher calorific value PCS and / or the lower calorific value PCI;

[0088] - the fluid is circulated in the circulator as described to convey the fluid to the reinjection means; thanks to the circulator according to the invention, the fluid can circulate very quickly at a determined speed, for example between 0.1 and 2 m / s. In addition, the circulator generates few pressure losses, is robust, simple and reliable and it can compensate for pressure losses or recompress the fluid in order to reintroduce the fluid at the pressure of the pipe; and

[0089] - the sampled fluid is reintroduced into the pipe using the reinjection means, positioned upstream, downstream or at the level of the sampling means (in the sampling means).

[0090] Thanks to the invention, the fluid that was released into the atmosphere is collected and reintroduced into the pipe. As a result, atmospheric discharges are considerably reduced, or even eliminated. When the fluid is a greenhouse gas, such as carbon dioxide or methane, the invention has a very significant environmental impact.

[0091] When the fluid is not harmful to the environment, the invention nevertheless remains very relevant because it limits unnecessary overconsumption of the fluid. Figures 6 and 7 illustrate, in a schematic and non-limiting manner, a fluid circulator according to one embodiment of the invention.

[0092] Figure 6 illustrates the case where the piston 25 moves towards the inlet chamber 50 while Figure 7 illustrates the case where the piston 25 moves towards the outlet chamber 51.

[0093] The circulator 6 comprises a cylinder 29 and a piston 25 capable of moving longitudinally in the cylinder 29.

[0094] The piston 25 is made of ferromagnetic material so that it can be driven longitudinally in the cylinder by the electromagnets 24 and 26 which are positioned around the cylinder. The system shown uses two electromagnets 24 and 26 but the system could also use a single electromagnet whose polarity would alternate regularly to drive the movement of the piston 25 back and forth.

[0095] With the two electromagnets 24 and 26, one can be activated alternately, then the other, so as to directly (without rotation) drive the piston in one direction then the other.

[0096] The cylinder 29 comprises a fluid inlet 28 and a fluid outlet 30. As shown, the electromagnets are positioned longitudinally one behind the other (in their axial direction), the electromagnet 24 facing the outlet chamber 51 and the electromagnet 26 facing the inlet chamber 50.

[0097] The cylinder 29 and the piston 25 delimit an inlet chamber 50, connected to the fluid inlet 28 and an outlet chamber 51 connected to the fluid outlet 30.

[0098] The piston 25 comprises a fluid passage orifice with a first non-return valve 32 equipped here with a return spring 31 (which nevertheless remains optional). This first non-return valve 32 is configured to open when the piston moves towards the fluid inlet 28 (thus towards the inlet chamber 50) as illustrated by the gray arrows in FIG. 6 and to close when the piston 25 moves towards the fluid outlet 30 (thus towards the outlet chamber 51) as illustrated by the gray arrows in FIG. 7. When it opens, the fluid can then pass into the passage orifice of the piston 25 and thus pass from the inlet chamber 50 to the outlet chamber 51.

[0099] The fluid outlet 30 also comprises a second non-return valve 22 here equipped with a return spring 21 (which nevertheless remains optional). This second non-return valve 22 is configured to open when the piston 25 moves towards the fluid outlet 30 (therefore towards the outlet chamber), as illustrated in FIG. 7 and to close when the piston 25 moves in the opposite direction, towards the inlet 28 (therefore towards the inlet chamber) as illustrated in FIG. 6.

[0100] The circulator shown also includes a third check valve 35 which is optional at the fluid inlet 28. This check valve 35 here includes a return spring 33 but it could not include a return spring. This check valve 35 is configured to open when the piston 25 moves towards the outlet chamber 51 (towards the fluid outlet 30), as illustrated in FIG. 7 and to close when the piston 25 moves in the opposite direction as illustrated in FIG. 6. The circulator also includes a spring 27 in the inlet chamber 50 connected to the inlet end of the cylinder 29 and to the piston 25 and a spring 21 in the outlet chamber 51 connected to the outlet end of the cylinder 29 and to the piston 25.

[0101] The circulator works as follows:

[0102] - When the piston 25 moves towards the fluid outlet 30, as in Figure 7, the fluid arrives in the inlet chamber 50 either directly (if there is no third non-return valve 35), or by the opening of this third non-return valve 35. The volume of the inlet chamber 50 increases. The first non-return valve 32 remains closed. The second non-return valve 22 is open: as the outlet chamber 51 has a volume which reduces, the fluid is driven towards the outlet 30 via the opening of the non-return valve 22.

[0103] When the piston 25 moves toward the fluid inlet 28, as in Figure 6, the volume of the inlet chamber 50 decreases. Since the pressure upstream of the inlet is constant (or the third check valve 35 is closed) and the first check valve 32 is open, fluid passes from the inlet chamber 50 to the outlet chamber 51 through the passage orifice of the piston 25 and through the open check valve 32. The second check valve 22 is closed.

[0104] Thus, the fluid passes progressively from the inlet 28 to the inlet chamber 50, from the inlet chamber 50 to the outlet chamber 51 and from the outlet chamber 51 to the outlet 30. The system therefore allows the circulation of the fluid in one direction only.

[0105] Of course, the system may include sealing means (not shown), in particular at the interface between the piston and the cylinder. These sealing means may be, for example, O-rings adapted to the fluid used on the one hand, to the operating pressure and temperature values ​​and to the dynamic conditions (piston movement speed).

[0106] As the movement of the piston and the fluid is linear (without rotation), the risks of mechanical heating are limited.

[0107] The circulator according to the invention allows for simple, robust fluid circulation, despite the continuous operation of the circulator. It also allows for reduced energy consumption compared to a pump or a rotary compressor.

[0108] Figures 2 to 5 illustrate, in a schematic and non-limiting manner, different embodiments of a fluid sampling and reinjection device according to the invention. Figure 2 illustrates a first embodiment of a fluid sampling and reinjection device according to the invention.

[0109] This fluid sampling and reinjection device comprises a sampling means 2 for sampling a fluid, such as a gas, more particularly biomethane, in a pipe 1, the fluid circulating in the direction F in the pipe 1.

[0110] The fluid sampling and reinjection device comprises a bypass line 3 which goes from the sampling means 2 to the means 7 for reinjecting the fluid into the pipe 1, this reinjection means being able to be downstream, in the direction of circulation F of the fluid in the pipe 1, from the sampling means 2 as shown, or on the contrary upstream or even at the same level as the sampling means 2.

[0111] The bypass line 3 comprises a circulator 6, for example that of figures 6 or 7 or one of its variants according to the invention. The circulator 6 is positioned between the sampling means 2 and the reinjection means 7.

[0112] The bypass line 3 may also optionally include an analysis system 4 for measuring certain parameters of the fluid such as, for example, its humidity level, its odorization level, its higher and / or lower calorific value, its content of certain chemical compounds such as hydrogen sulfide H2S.

[0113] The analysis system 4 can advantageously be placed between the sampling means 2 and the circulator 6. As shown in the figure, the circulator 6 is downstream of the analysis system 4 but it could alternatively be upstream.

[0114] The analysis system 4 and / or the circulator 6 can be positioned in a shelter.

[0115] Figure 3 illustrates a second embodiment of the sampling and reinjection device according to the invention.

[0116] References identical to those in Figure 2 correspond to the same elements and will not be detailed again.

[0117] In this figure, the analysis system 4 comprises several analysis means 8a and 8b (the figure illustrates two analysis means but of course could comprise a single one or include others in addition). The analysis means 8a and 8b are positioned in parallel to each other from a branch line starting from the bypass line but the analysis means 8a and 8b could just as well be placed in series.

[0118] The fluid at the outlet 9 of each of the analysis means 8a and 8b is discharged into the atmosphere or recompressed for other uses.

[0119] Figure 4 illustrates a third embodiment of the sampling and reinjection device according to the invention. References identical to those of Figures 2 or 3 correspond to the same elements and will not be detailed again. The bypass line comprises, in addition to the elements of Figure 3, a pressure relief means 10, such as a pressure reducer, so as to limit the pressure downstream of the pressure relief means 10. This may have an impact on the ATEX (Explosive Atmosphere) classified environment or not of the equipment located in the shelter. When the environment is not ATEX classified, the equipment is simpler and less expensive. The pressure relief means 10 may or may not be positioned in the shelter.

[0120] As the fluid is expanded in the expansion means 10, the circulator 6 can also be used to recompress the fluid before its reinjection into the pipe 1, by the reinjection means 7. In other words, the circulator 6 is also a compression means.

[0121] Figure 5 illustrates a fourth embodiment of the sampling and reinjection device according to the invention.

[0122] References identical to those in figures 2 to 4 correspond to the same elements and will not be detailed again.

[0123] In this embodiment, the fluid leaving the analysis means 8a and 8b is conveyed by conduits 12a and 12b to a reservoir 11 positioned on the bypass line upstream of the circulator 6, preferably between the expansion means 10 and the circulator 6. Thus, the fluid leaving the analysis system 4 (i.e. the different analysis means 8a and 8b) is collected in the reservoir 11 to be reintroduced into the conduit 1 via the circulator 6 and the reinjection means 7.

[0124] In this case, the circulator 6 is downstream of the analysis system 4.

[0125] Of course, the various options illustrated in Figures 2 to 5 may be combined or not without departing from the scope of the invention. They may also be combined with the various circulator options described in this description and in particular those described in relation to Figures 6 and 7.

Claims

Claims 1. Circulator (6) for fluid, preferably gas, comprising a cylinder (29) and a ferromagnetic piston (25) capable of moving longitudinally in the cylinder (29), along the axis of the cylinder, the cylinder (29) delimiting an inlet chamber (50) and an outlet chamber (51) separated by the piston (25), the cylinder (29) comprising an inlet (28) for the fluid connected to the inlet chamber (50) and an outlet (30) for the fluid connected to the outlet chamber (51), the circulator (6) comprising a first non-return valve (32) in the piston (25) configured to open when the piston (25) moves towards the inlet chamber (50) so as to allow the passage of the fluid from the inlet chamber (50) to the outlet chamber (51) and a second non-return valve (22) positioned at said outlet (30) of the fluid,the second non-return valve (22) being configured to open when the piston (25) moves towards the outlet chamber (51), to allow the fluid to exit the circulator (6), characterized in that the circulator (6) comprises at least one electromagnet (24, 26) for directly driving the piston (25) in translation in a reciprocating motion in the cylinder (29), the at least one electromagnet (24, 26) being arranged around the cylinder (29), and in that each of the inlet (50) and outlet (51) chambers comprises a spring (27, 21) fixed on the one hand to a longitudinal end of the cylinder (29) and on the other hand to the piston (25)., 2. Fluid circulator (6) according to claim 1, wherein the circulator (6) comprises two electromagnets (24, 26) arranged around the cylinder (29), one of the two electromagnets (24, 26) being configured to set the piston (25) in motion in one direction, the other of the two electromagnets (24, 26) being configured to set the piston (25) in motion in the other direction, preferably the two electromagnets (24, 26) being arranged longitudinally, along the longitudinal axis of the cylinder (29), one behind the other.

3. Fluid circulator (6) according to one of the preceding claims, wherein the circulator (6) comprises a third non-return valve (35) at the fluid inlet (28) for introducing the fluid into the inlet chamber (50), the third non-return valve (35) being configured to open when the piston (25) moves towards the outlet chamber (51).

4. Fluid circulator (6) according to one of the preceding claims, wherein the first non-return valve (32), the second non-return valve (22) and / or the third non-return valve (35) comprises a spring (31, 21, 33) for increasing the value of the opening pressure by a predetermined value.

5. Device for sampling and re-injecting a fluid into a pipe (1), comprising a bypass line (3) for diverting at least part of the fluid from the pipe (1), the bypass line (3) comprising a means (2) for sampling the fluid from the pipe to introduce the sampled fluid into the bypass line (3) and a means (7) for re-injecting the fluid into the pipe (1), the bypass line (3) comprising a fluid circulator (6) according to one of claims 1 to 4 in the bypass line (3).

6. Device for sampling and re-injecting a fluid into a pipe (1) according to claim 5, for which the bypass line (3) comprises at least one fluid analysis system (4) downstream of the fluid sampling means (2), in the direction of circulation of the fluid in the fluid sampling and re-injecting device, in particular upstream of the circulator (6), preferably, the analysis system (4) comprises at least one analysis means (8a, 8b), such as a chromatograph.

7. Device for sampling and reinjecting a fluid into a pipe (1) according to claim 6, for which the bypass line (3) comprises equipment comprising a fluid exhaust channel, and / or the analysis system (4) and / or at least one analysis means (8a, 8b) comprises a fluid exhaust conduit.

8. Device for sampling and reinjecting a fluid into a pipe (1) according to claim 7, for which at least one exhaust channel and / or at least one exhaust duct, preferably all the exhaust channels and all the exhaust ducts, are fluidically connected to a reservoir (11), the reservoir (11) being positioned on the bypass line (3), upstream of the circulator. (6) of the fluid.

9. Device for sampling and reinjecting a fluid into a pipe (1) according to one of claims 5 to 8, for which the bypass line (3) comprises a means (10) for expanding the fluid between the sampling means (2) and the analysis system (4), the fluid circulator (6) then being configured to recompress the fluid to a pressure substantially equal to the pressure of the pipe (1).

10. Device for sampling and re-injecting a fluid into a pipe (1) according to one of claims 5 to 9, for which the re-injection means (7) and the sampling means (2) are the same and unique equipment which allows the sampling and re-injection of the fluid into the pipe (1) or for which the re-injection means (7) is positioned upstream or downstream of the sampling means (2) on the pipe (1), in the direction of circulation of the fluid in the pipe (1). Method for sampling and re-injecting fluid from the sampling and re-injection device according to one of claims 5 to 10, for which at least the following steps are carried out: - a fluid is taken from a pipe (1), by the taking-off means (2), to introduce it into a bypass line (3); - preferably, the sampled fluid is analyzed to determine its chemical composition or its content of certain compounds, the compounds preferably comprising THT, H2S, H2O and / or PCS; - the fluid is circulated in the circulator (6) to convey the fluid to the reinjection means (7); and - the fluid taken from the pipe (1) is reintroduced using the reinjection means (7), positioned upstream, downstream or at the level of the sampling means (2).

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