Hydraulic machine connection including a flow meter

Abstract

The device (7) comprises: - a conduit (10) having an internal face (12) extending along an axis (XX); - a flow meter (14) defining a measurement direction (D) in the conduit, the direction being inclined relative to the axis and intercepting the internal face, the flow meter delimiting a measurement zone in the conduit; and - at least one sensor (22, 24) distinct from the flow meter, the sensor extending outside the measurement zone or in a plane (P1, P2) perpendicular to the axis and passing through the flow meter. Figure 1

Description

Title of the invention: Connection for a hydraulic machine comprising a flow meter FIELD OF THE INVENTION

[0001] The invention relates to rotating hydraulic machines. STATE OF THE ART

[0002] Rotating hydraulic machines are known that operate as motors or pumps. For example, this is a hydraulic wheel motor of a machine or vehicle, a motor in which the fixed part comprises hydraulic pipes and the rotating part comprises a piston cylinder block and is connected to an output shaft receiving a wheel. The pistons bear against a corrugated cam carried by the fixed part. Pressurizing the machine allows the pistons to move on the cam, which sets the wheel in rotation. The machine comprises a casing comprising a flange for attachment to the chassis of the machine.

[0003] When such a machine breaks down, it results in the temporary immobilization of the machine or vehicle for repair or replacement, which generates immobilization costs, in addition to the repair or replacement costs.

[0004] An aim of the invention is to better understand the state of health of the machine and to facilitate its predictive maintenance in order to be able to detect in advance when such a machine will require servicing or preventive maintenance. Statement of the invention

[0005] To this end, according to the invention, a device is provided comprising:

[0006] - a conduit having an internal face extending along an axis;

[0007] - a flow meter defining a measurement direction in the conduit,

[0008] the direction being inclined relative to the axis and intercepting the internal face,

[0009] the flow meter delimiting a measurement zone in the conduit; and

[0010] - at least one sensor (distinct from the flow meter,

[0011] the sensor extending outside the measurement zone or in a plane perpendicular to the axis and passing through the flow meter.

[0012] Thus, the flow meter makes it possible to know an instantaneous value of the fluid flow in the conduit in communication with the hydraulic machine. The sensor gives another quantity in the same conduit and at the same time. The joint knowledge of these two quantities makes it possible, if necessary, to detect a drop in performance of the machine or an operating anomaly, and if necessary to plan a maintenance operation. The positioning of the sensor outside the zone or at the edge of it makes it possible to avoid generating turbulence in the portion of the conduit used for the flow measurement, to make it more accurate. Flow measurement also makes it possible to determine the volumetric efficiency if we know the inlet flow upstream of the measurement point (from the speed). Using this data, we can search for the best efficiency point of the machine, and, if it forms an engine, particularly for a vehicle, improve its traction.

[0013] It can be provided that the flow meter is an ultrasonic flow meter.

[0014] It can be provided that the conduit is made of a material permeable to ultrasound, for example PEEK.

[0015] It can be provided that the flow meter is a flow meter measuring travel time.

[0016] The device may also have at least one of the following characteristics:

[0017] - the flow meter comprises a first transceiver and a second transceiver receiver, the first transceiver and the second transceiver being aligned along the direction, the sensor extending out of the measurement area or in a plane perpendicular to the axis and passing through one of the first transceiver and the second transceiver;

[0018] - the first transmitter-receiver has a transmission-reception axis coinciding with the direction and the second transceiver has a transmission-reception axis coinciding with the direction; and

[0019] - the first transmitter-receiver has a transmission-reception axis and the second transmitter-receiver has a transmission-reception axis, at least one of the two transmission-reception axes being non-coincident with the direction.

[0020] It can also be provided that the flow meter is Doppler effect.

[0021] It can be provided that the direction forms an angle with the axis of between 20 and 70°.

[0022] An installation is also provided comprising:

[0023] - a hydraulic machine,

[0024] - a device according to the invention, and

[0025] - at least one fluid circuit configured to put the device in communication with the machine.

[0026] It can be provided that the circuit comprises a drain.

[0027] A method is also provided in which:

[0028] - a fluid flow rate is determined in an area of ​​a conduit in communication with a hydraulic machine, and

[0029] - at least one quantity is measured from a fluid temperature and a pressure fluid in the conduit upstream or downstream of the zone.

[0030] In the method, it can be provided that the machine operates as a pump or as a motor.

[0031] The method may be controlled by automated means associated with a program comprising code instructions controlling the implementation of the method when it is executed on such means.

[0032] These means can be programmed to send an alert message when one of the quantities measured by the device exceeds a predetermined threshold, a sign of an anomaly. DESCRIPTION OF FIGURES

[0033] We will now describe embodiments of the invention with the support of the appended figures given as non-limiting examples and in which:

[0034] - [Fig.l] is a diagram of an installation according to an embodiment of the invention comprising a device according to the invention and a hydraulic machine;

[0035] - [Fig.2] is a cross-sectional view of the device of [Fig.l];

[0036] - [Fig.3], [Fig.4] and [Fig.5] are diagrams similar to [Fig.l] showing variants of the device;

[0037] - [Fig.6] illustrates a more detailed arrangement of the device of [Fig.l];

[0038] - [Fig.7] is a sectional view of an example of a rotating hydraulic machine forming part of the invention; and

[0039] - [Fig.8] is a view similar to [Fig.l] illustrating a second mode of realization. DETAILED DESCRIPTION OF THE INVENTION First embodiment

[0040] Figures 1 and 2 illustrate an installation 2 according to a first embodiment of the invention. The installation 2 comprises:

[0041] - a rotating hydraulic machine 6,

[0042] - a device 7 according to a first embodiment of the invention, and

[0043] - at least one fluid circuit 9 configured to put the device 7 in communication with the machine.

[0044] We will first describe the device 7.

[0045] It comprises a conduit 10 having an internal face 12 extending along an axis XX. The conduit thus forms a tubular body or sleeve open at its two axial ends. When the device 7 is in operation, the internal face 12 therefore forms a fluid vein in communication with the machine 6.

[0046] In this example, the internal face 12 has a cylindrical shape. In particular, it has here a profile having a cross-section which has a length greater than a width of the section, as illustrated in [Fig.2]. This makes it possible to give the fluid a more homogeneous speed in a large part of the section. The section here has a rectangular shape, as illustrated in the same figure. But the section can be given a different shape, for example circular, oval or elliptical.

[0047] The device 7 also comprises an ultrasonic flow meter 14. In this example, the flow meter 14 is a flow meter measuring travel time or transit time. It comprises in this case a first transceiver 16 and a second transceiver 18, these two elements being aligned in a direction D inclined relative to the axis XX. The direction forms an angle with the axis of between 20 and 70°. It can be between 30 and 40° and is for example 45°. Each of the transceivers forms an ultrasonic transducer.

[0048] The respective axial positions of the two transceivers delimit a measurement zone 21 in the conduit 10. The axis XX extends between the transceivers so that the latter are located on either side of the axis. With reference to the direction 34 of flow of the fluid in the conduit, the transceiver 16 is located downstream of the transceiver 18.

[0049] In operation, the downstream transceiver 16 sends an acoustic wave to the upstream transceiver 18, and automated means measure the travel time of this wave. In a second step, the upstream transceiver 18 sends an acoustic wave to the downstream transceiver 16, and the corresponding second travel time is measured. The difference in duration between the two paths of the wave makes it possible to obtain the speed of the fluid. By knowing the area of ​​the cross-section of the conduit, the flow rate of the fluid is deduced by the automated calculation means.

[0050] In this example, the two transmitters-receivers 16, 18 do not open into the conduit 10.

[0051] The measurement zone 21 corresponds to the longitudinal section of the conduit 10 crossed by the ultrasonic waves.

[0052] The downstream transmitter-receiver 16 has a transmission-reception axis VV and the upstream transmitter-receiver 18 has a transmission-reception axis MM, at least one of these two axes being non-coincident with the direction D, preferably the two axes being non-coincident, as illustrated in [Fig.l]. This arrangement makes it possible to compensate for the deflection of the sound waves which occurs by refraction during the change of medium at the outlet of each transmitter-receiver towards the fluid in the conduit. In this case, the tubular body is made of a material permeable to ultrasound, for example PEEK.

[0053] As a variant, it can be provided that the axes VV and MM coincide with the direction D and are therefore merged with it, in particular when the transmitters-receivers are mounted opening into the conduit 10.

[0054] The device 7 also comprises at least one sensor distinct from the flow meter 14. In this case, it comprises two sensors distinct from the flow meter, namely in this example a temperature sensor 22 and a pressure sensor 24.

[0055] In this case, each of these sensors 22, 24 extends in a plane perpendicular to the axis XX and passing through one of the transmitter-receiver 16 and the transmitter-receiver 18. Thus one of the sensors, in particular the pressure sensor 24, extends in a plane PI passing through the transmitter-receiver 16 and the other sensor, in particular the temperature sensor 22, extends in a plane P2 passing through the transmitter-receiver 18, as illustrated in [Fig.l]. Indeed, the inclination of the direction D relative to the axis XX provides two zones located at right angles to the two transmitter-receivers respectively, zones which make it possible to house one or more sensors without them disturbing the operation of the flow meter 14. In addition, a particularly compact device 7 is thus obtained. Each of the sensors extends outside the measurement zone 21. This makes it possible to avoid any disturbance of the flow at the location of the flow measurement.

[0056] The conduit 10 thus forms a measuring chamber.

[0057] According to the variant of [Fig. 3], the temperature sensor 22 and the pressure sensor 24 are combined in an element 26 mounted in the wall of the conduit 10. One of the sensors, here the sensor 22, extends in the plane PI and the other, here the sensor 24, extends downstream of the latter.

[0058] Generally, it is expected that the temperature 22 and pressure 24 sensors are placed as close as possible to the fluid stream.

[0059] According to the variant of [Fig. 4], the sensor or at least one of the sensors 22, 24 is placed in a housing 28 formed in the wall of the conduit 10 and which opens into the internal face 12 and therefore into the fluid stream. In this way, the sensors are placed in through-holes formed in the material of the body of the device 7, so that their end connects smoothly with the internal face of the conduit.

[0060] Alternatively, they may be slightly set back from this face and form an offset. This offset may create slight turbulence in the fluid, but if the sensors are placed in the indicated areas, this does not affect the velocity measurement. The remaining space, generated by this setback, may however be filled with glued or molded material to preserve a smooth surface in the fluid stream.

[0061] According to the variant of [Fig. 5], the housing 28 is separated from the internal face 12 by a wall 31. Thus, the two sensors 22 and 24 can be placed in non-opening wells in the material of the conduit 10, as is also shown in [Fig. 1]. An optional feature is also found in the arrangement of [Fig. 3]. There thus remains a thin wall 31 between the fluid and the sensors 22, 24. This wall is thin and flexible enough to transmit the pressure of the fluid to the pressure sensor 24. It is also thin and thermally conductive enough to transmit the temperature of the fluid to the temperature sensor 22. The advantage of using non-opening wells is to guarantee good sealing of the sensor mounting and to present a smooth area for the fluid stream.

[0062] The sensors 22, 24 can be screwed into the material of the body of the device 7, inserting a seal if necessary. They can also be glued. Alternatively, if the body of the device 7 is obtained by molding plastic material, they can be overmolded in it.

[0063] With particular regard to the temperature sensor 22, an interface 25 made of heat-conducting material, for example copper, may be interposed between the temperature sensor and the fluid, as illustrated in [Fig.l]. This interface may be overmolded or inserted in a sealed manner into the body of the device 17, which makes it possible to remove or replace the temperature sensor 22 easily, without having to worry about sealing with a pressurized fluid.

[0064] The flow meter 14 and the sensors 22, 24 may be commercial sensors.

[0065] A more detailed arrangement of the device 7 of [Fig.l] is illustrated in [Fig.6].

[0066] An example of an embodiment of the machine 6 is illustrated in [Fig.7]. Others machine configurations are possible.

[0067] The machine 6 comprises a casing 8 in two parts 30, 32 fixed to each other by members 34 such as screws. It comprises a shaft 36 having a longitudinal axis YY. The machine is generally revolutionally symmetrical about this axis. Bearings 20 serve to support the shaft 36 mounted to rotate in the casing 8. They are for example two in number and comprise cylindrical or frustoconical bearings. The two bearings 20 are in this case in direct support against the part 32 of the casing. Alternatively, the machine 6 comprises a single bearing 20.

[0068] The machine comprises a cylinder block 38 having housings 40 radial to the axis, the cylinder block being integral in rotation with the shaft 36. Pistons 42 are received in the respective housings 40 and mounted to slide radially to the axis in these housings.

[0069] The machine comprises a cam 44 rigidly fixed to the casing 8 by being interposed between parts 30 and 32 and which has an internal face forming a rolling track for rollers connected to the respective pistons 42. The pistons bear on the cam 44 by means of the rollers. The track has lobes whose alternation around the axis corresponds to a back-and-forth movement of the pistons during the rotation of the shaft 36 relative to the casing 8.

[0070] The machine comprises a distributor 46 capable of placing the housings 40 of the pistons in communication with a high-pressure fluid circuit and with a low-pressure fluid circuit. The distributor is connected by conduits to the fixed part of the machine, so as to be connected to the hydraulic fluid network of the machine or installation. The casing 8, the cam 44 and the distributor 46 correspond to the fixed part of the machine. The shaft 36, the cylinder block 38 and its pistons and the flange 50 form the rotating part of the hydraulic machine.

[0071] The machine can form a pump or a motor. In motor mode, depending on the command applied to it, it can operate in traction or in restraint, that is to say provide a positive or negative rotational torque, and this in one or the other of the two possible directions of rotation.

[0072] A more detailed description of these elements of the machine can be found in application FR-2 796 886, this document being mentioned here only as an example for such a machine.

[0073] The fluid circuit 9 forms, for example, a drain of the casing of the machine. But the device 7 can be mounted on other hydraulic lines of the machine than the drain, for example on a supply or discharge circuit. The device 7 is fixed, for example, to a hydraulic inlet or outlet of the machine, of a pump supplying the machine, or of a valve, for example by means of a thread for hydraulic piping. The device 7 can also be fixed anywhere in a hydraulic circuit connected to the machine 6, along its drain or its supply or discharge pipes.

[0074] As illustrated in [Fig.6], the section of the fluid stream in the circuit 9 is for example circular at the inlet of the device 7, the ends of the device being connected to the circuit for example by means of screwed connections, then changes shape in the measuring chamber where it can be crossed by the wave beam of the flow meter 14, then becomes circular again at the outlet. In a preferred manner, the section of the stream remains substantially constant despite these changes of shape.

[0075] The device 7 can itself form a connection.

[0076] This installation 2 makes it possible to implement the method of the invention in an example as follows.

[0077] With the hydraulic machine in operation, a fluid flow rate is measured by means of the flow meter 14 in a zone of the conduit 10 in communication with the machine, in this case in the measurement zone 21. This measurement is carried out as indicated above, which makes it possible to obtain the fluid flow rate.

[0078] Simultaneously or concomitantly, at least one quantity is measured from among a temperature of the fluid and a pressure of the fluid in the conduit 10 upstream or downstream of the zone, by means of the sensors 22 and 24.

[0079] The device 7 makes it possible to take measurements at the same location to know and monitor the state of the machine in real time. The flow and pressure information makes it possible to evaluate the efficiency of the hydraulic machine, and for a motor, the torque it delivers. The temperature information makes it possible to refine the evaluation according to the viscosity of the fluid.

[0080] When the device 7 is in communication with the drain, it makes it possible to monitor the leakage flow rate, a flow rate which changes depending on the state of health of the machine. Similarly, Temperature monitoring allows an abnormal increase in temperature to be detected and possible damage to be prevented. Second embodiment

[0081] A second embodiment of the invention is illustrated in [Fig.8].

[0082] The characteristics common to the first mode will not be repeated and we will only present the differences. Similarly, the variants set out in relation to the first mode are also applicable with this second mode.

[0083] Here, the flow meter 14 is Doppler effect. It is based on a measurement of particle speed by Doppler effect. In particular, this method uses the reflection of a wave by particles. In this example, the flow meter comprises a single transmitter-receiver which emits a wave train at a given frequency. The fluid comprises particles 15 carried in motion with it. Such a particle 15 reflects the wave towards the transmitter-receiver, a wave which is received with a frequency different from the transmission frequency. The frequency difference is representative of the speed of movement of the particle, therefore that of the fluid. Automated calculation means therefore make it possible to determine the flow rate.

[0084] The transceiver transmits the wave train along direction D, here inclined at 45° relative to the XX axis, which forms an optimal angle relative to the flow. However, this angle can be located in a range of 20 to 70°. An angle much less than 45° creates a significant attenuation of the frequency difference. An angle much greater than 45° creates an attenuation of the amplitude of the received signal as the particle moves away from the flow meter.

[0085] The moving particles may be solid particles present in the hydraulic fluid, such as impurities from the machine or the oil forming the fluid, for example wear particles from the machine or particles from the filter media of the hydraulic circuit. They may also be air bubbles or cavitation. Generally speaking, any heterogeneity in the hydraulic fluid can be detected in this way and used for flow measurement.

[0086] In this case, the flow meter 14 comprises a single element. The measurement zone 21 is delimited by the axial positions of the points 17 at which the direction D intercepts the internal face 12 of the conduit when entering the vein and leaving it.

[0087] It is observed that the two sensors 22, 24 are outside this zone. Alternatively, at least one of the two sensors could be located at the right of the flow meter and / or at the right of one of the points 17.

[0088] Numerous modifications may be made to the invention. It may be provided that the sensor or one of the sensors forms an accelerometer or ensures a counting of particles in the fluid.

Claims

Claims

1. Device (7) comprising: - a conduit (10) having an internal face (12) extending along an axis (XX); - a flow meter (14) defining a measurement direction (D) in the conduit, the direction being inclined relative to the axis and intercepting the internal face, the flow meter delimiting a measurement zone in the conduit; and - at least one sensor (22, 24) separate from the flow meter, the sensor extending outside the measurement zone or in a plane (PI, P2) perpendicular to the axis and passing through the flow meter.

2. Device according to the preceding claim in which the flow meter (14) is an ultrasonic flow meter.

3. Device according to one of the preceding claims in which the conduit (10) is made of a material permeable to ultrasound, for example PEEK.

4. Device according to one of the preceding claims in which the flow meter (14) is a flow meter measuring travel time.

5. Device according to the preceding claim in which the flow meter comprises a first transceiver (16) and a second transceiver (18), the first transceiver and the second transceiver being aligned in the direction (D), the sensor (22, 24) extending outside the measurement zone or in a plane (PI, P2) perpendicular to the axis and passing through one of the first transceiver and the second transceiver.

6. Device according to the preceding claim in which the first transceiver (16) has a transmission-reception axis (VV) coinciding with the direction (D) and the second transceiver (18) has a transmission-reception axis (MM) coinciding with the direction (D).

7. Device according to claim 5 in which the first transceiver (16) has a transmission-reception axis (VV), and the second transceiver (18) has a transmission-reception axis (MM),

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21. at least one of the two transmission-reception axes being non-coincident with the direction (D). Device according to one of claims 1 to 3 in which the flow meter (14) is Doppler effect. Device according to one of the preceding claims in which the direction (D) forms an angle with the axis (XX) of between 20 and 70°. Device according to one of the preceding claims in which the internal face (12) has a cylindrical shape. Device according to one of the preceding claims in which the internal face (12) has a profile having a section which has a length greater than a width of the section. Device according to the preceding claim in which the section has a rectangular, oval or elliptical shape. Device according to one of the preceding claims in which the sensor or one of the sensors is a temperature sensor (22). Device according to one of the preceding claims in which the sensor or one of the sensors is a pressure sensor (24). Device according to claims 13 and 14 in which the temperature sensor (22) and the pressure sensor (24) are combined in an element mounted in the conduit (10). Device according to one of the preceding claims in which the sensor (22, 24) or one of the sensors is placed in a housing (28) provided in the conduit (10). Device according to the preceding claim in which the housing (28) opens into the internal face (12). Device according to claim 16 in which the housing (28) is separated from the internal face (12) by a wall (31). Installation (2) comprising: - a hydraulic machine (6), - a device (7) according to one of the preceding claims, and - at least one fluid circuit (9) configured to put the device in communication with the machine. Installation according to the preceding claim in which the circuit (9) comprises a drain. Process in which: - a fluid flow rate is determined in an area of ​​a conduit (10) in communication with a hydraulic machine (6), and - at least one quantity is measured from a fluid temperature and a fluid pressure in the conduit upstream or downstream of the zone.

22. Method according to the preceding claim in which the machine (6) operates as a pump.

23. Method according to claim 21 in which the machine (6) operates as a motor.

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