Connection with mechanical stress detection

Abstract

A fitting (1; 101) for connecting a pipe in a fluid supply network is proposed. The fitting comprises a main fitting body (10; 110) having a pipe insertion space (20a, 20b) extending in an axial direction XX, between an open end (11a, 11b) and an internal radial rib (12) extending radially inwards from an internal body surface (15) and provided for stopping a pipe inserted into the main fitting body (10), a first electromagnetic device (30; 130) arranged in or on the main fitting body (10; 110) and extending parallel to the main fitting body, and a second electromagnetic device (40; 140) extending parallel to the main fitting body and arranged with a clearance with the main fitting body.The first electromagnetic device and the second electromagnetic device provide an electromagnetic interaction between them representative of a current mechanical state of the fitting. Figure for the abbreviation: Figure 1.

Description

Title of the invention: Fitting with mechanical stress detection. Technical field

[0001] The present invention relates to the field of fittings, such as electrofusion fittings. In particular, the present invention relates to a fitting for connecting a pipe in a fluid supply network, a fitting assembly comprising such a fitting connecting a first pipe and a second pipe, and a method for characterizing a fitting assembly. PREVIOUS ART

[0002] Fittings are commonly used in pipe arrangements for connecting pipes. For different pipe arrangements, fittings can be designed as curved, angled, or T-shaped pieces, generally with one, two, or three connecting pieces.

[0003] The pipe or tube can be single-material and made of thermoplastic materials including, but not limited to, PE, PB, PEX, PERT, PER... or composite (multi-material tube structure) with different layers of functional materials (PEX, PERT, PVDF, Aluminium...).

[0004] A pressure fitting made entirely of plastic, or a pressure fitting having a fitting body made of metal (brass, stainless steel...), or thermoplastic (PVC, PPSU, PVDF, PPS), which can also be reinforced with a fiberglass reinforcement, can also be considered.

[0005] In operation, the fittings are subjected to stresses which can lead to failure of the fitting and / or associated pipes.

[0006] It would be useful to be able to know the mechanical condition of a fitting, and of the fittings in a network, for maintenance purposes. Summary of the invention

[0007] To this end, the present invention proposes a fitting with a detection device for detecting a mechanical state of the fitting, such as stresses in the fitting and connected pipes. The stresses may be an impact, misalignment, expansion, etc.

[0008] The fitting for connecting a pipe in a fluid supply network comprises a main fitting body having a pipe insertion space extending in an axial direction XX, between an open end and an internal radial rib extending radially inwards from an internal body surface and provided for stopping a pipe inserted into the main fitting body, A first electromagnetic device arranged in or on the main fitting body and extending parallel to the main fitting body, and a second electromagnetic device extending parallel to the main fitting body and arranged with some clearance from the main fitting body. The first electromagnetic device and the second electromagnetic device provide an electromagnetic interaction between them that represents a current mechanical state of the fitting.

[0009] The detection device includes a transformer made of a first and a second electromagnetic device interacting together to produce a signal representative of the connection.

[0010] The first electromagnetic device comprises at least one first solenoid and the second electromagnetic device comprises at least one second solenoid.

[0011] Preferred electromagnetic devices include at least a first solenoid and at least a second solenoid.

[0012] The first solenoid is embedded in the fitting. The second solenoid is either in an internal sleeve inside the fitting, in particular inside the pipe, or in an external sleeve on the fitting.

[0013] The connector can be an electrofusion device, and the electrofusion wire is the first solenoid. This allows the electrofusion wire to be reused.

[0014] In one aspect, the second electromagnetic device is placed in an internal sleeve positioned inside the fitting, preferably flush with the free end of the radial rib.

[0015] The inner sleeve can be positioned on a bearing at the free end of the radial rib. In particular, the inner sleeve is arranged inside the fitting, so that, in operation, the second electromagnetic device is arranged inside a pipe inserted into the main fitting body.

[0016] In another aspect, the second electromagnetic device is placed in an external sleeve positioned outside the fitting, preferably with a gap with the fitting.

[0017] The outer sleeve can be grounded to an external reference.

[0018] In one aspect, the inner or outer sleeve is made of a thermally stable material, such as carbon or fiberglass. The inner or outer sleeve has a sleeve expansion coefficient close to zero.

[0019] In one aspect, the fitting has at least one strain gauge on an external body surface of the main fitting body.

[0020] In one aspect, the fitting is provided with a connection that can be connected to a power supply that can be connected to a measuring device to deliver an induced current.

[0021] In one aspect, a microcontroller is provided to send stress data and measured current to a monitoring system and / or receive instruction signals from the monitoring system, in particular to control the power supply.

[0022] A fitting assembly is also proposed which includes such a fitting connecting a first pipe and a second pipe. The fitting assembly has a power supply for providing an alternating current to one of the first or second electromagnetic devices, to generate a magnetic field, and a measuring device provided for measuring an induced current I in one of the first or second electromagnetic devices.

[0023] In one aspect, the fitting assembly has a monitoring system and a microcontroller to send measured current and stress data to a monitoring system and / or receive instruction signals from the monitoring system.

[0024] In another aspect, a method for monitoring / diagnosing / characterizing a fitting assembly is proposed. The method comprises supplying an alternating current to one of the first electromagnetic devices or the second electromagnetic device, to generate a magnetic field Bl, measuring an induced current I in the other of the first electromagnetic device and the second electromagnetic device, and deriving a current mechanical state of the fitting based on the measured induced current I, wherein the current mechanical state includes information concerning stresses on the first pipe, the second pipe and / or the main fitting body, such as misalignment, thermal expansion, cracks, of / on the first pipe, expansion of the second pipe, expansion of the main fitting body.

[0025] In one aspect, the method includes operating a strain gauge to obtain applied strain data on the first and second pipes and / or the main fitting body, and correlating the induced current and strain data to derive the current mechanical state of the fitting.

[0026] One of the first and second solenoids is powered by an alternating current and generates a varying magnetic field. This magnetic field, in turn, induces a varying current in the other of the first and second solenoids.

[0027] The measured induced current variations evolve according to the thermal expansions and stresses to which the first and / or second solenoid is / are subjected. Monitoring these variations makes it possible to characterize the expansions and stresses in the pipes and in the fitting.

[0028] When the fitting is an electrofusion fitting system including fusion equipment, it is proposed to reuse the electrofusion wire as the first solenoid when it is no longer used for its primary welding function. In other words, the electrofusion equipment, once the welding is complete, can be used for additional measurement / processing capabilities to add further characteristics that allow for the characterization of the fitting and / or the pipes.

[0029] The inner sleeve is made of a more stable material (e.g., carbon) than the pipe and fitting materials. The inner sleeve is thermally stable and will be less affected by heating than the outer sleeve, which is made of thermoplastic. Differential expansion will affect the relative configuration of the solenoids. DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages of the invention will become more apparent upon reading the description of several currently preferred embodiments, given solely by way of example, with reference to the accompanying drawings, in which:

[0031] [Fig. 1] shows an exploded cross-sectional view of a mechanical fitting according to one aspect of the present disclosure,

[0032] [Fig.2] shows a mechanical fitting according to one aspect of the present disclosure,

[0033] [Fig.3] shows a monitoring system that can be used with a fitting according to one aspect of this disclosure,

[0034] [Fig.4] shows a mechanical fitting according to one aspect of the present disclosure. DETAILED DESCRIPTION

[0035] In the figures, identical parts are identified using the same reference numbers.

[0036] Fig. 1 represents a fitting 1 for connecting a first pipe 2 and a second pipe 3. The first and second pipes 2, 3 can be, for example, a pipe for / in a piping system for fluid installations inside buildings, for example, a fluid supply network such as drinking water, hot water, gas, as well as for industrial applications, for example, hydrogen, ammonia, methanol, etc., where safety issues are the primary reason why the condition of the networks must be constantly monitored.

[0037] The pipe or tube can be single-material and made of thermoplastic materials including, but not limited to, PE, PB, PEX, PERT, PER... or composite (multi-material tube structure) with different layers of functional materials (PEX, PERT, PVDF, Aluminium...).

[0038] The first pipe 2 has a first coefficient of expansion, the second pipe 3 has a second coefficient of expansion.

[0039] In the example in [Fig. 1], fitting 1 forms a connector with similar connections on both sides. This is only one example, and fitting 1 can form a connector with a different type of fitting on its other end or side. The fitting can also be provided at an orifice of a fluidic device to connect a hose to it.

[0040] Furthermore, while the fitting in [Fig.1] is intended to join two pipes, this does not limit the invention and the fitting can be an end fitting to connect a single pipe to an orifice.

[0041] The mechanical fitting 1 includes a main fitting body 10 for receiving the pipes.

[0042] The main fitting body 10 has an external body surface 14 and an internal body surface 15, with the internal body surface 15 designed to rest against the external surfaces of the pipes inserted into it. The main fitting body 10 has a first and second pipe insertion spaces 20 extending in an axial direction XX, between a first and second open ends 1a, 11b, i.e., the end where the pipe is inserted, and an internal radial rib 12 extending radially inward from the internal body surface 15.

[0043] The internal radial rib 12 is provided to stop the pipes inserted into the main fitting body 10.

[0044] The main connecting body 10 can be made of thermoplastic materials... The main connecting body has a connecting expansion coefficient.

[0045] A first solenoid 30 is placed in the main connecting body 10. The first solenoid 30 can be molded into the main connecting body 10. The first solenoid can be placed on the external body surface 15 or embedded in the main connecting body 10.

[0046] An internal sleeve 40 housing a second solenoid 45 is placed inside the fitting 1. The internal sleeve 40 is a mechanically free sleeve 40 resting on a bearing 43 on / in the internal body surface 15.

[0047] The inner sleeve 40 extends in the axial direction XX, parallel to the internal body surface 15 of the main connecting body 10.

[0048] In the example of [Fig.1], the pipe ends are inserted into the fitting and the inner sleeve 40 extends parallel to the pipe, with a gap 9 with the pipes 2, 3. There is an O-ring in the gap to allow alignment of the inner sleeve without friction.

[0049] In the example of [Fig. 2], the pipe ends were hollowed out before insertion to form a housing space 8 for the inner sleeve 40. The ends of The pipes have been hollowed out so that, within the hollow, the pipe end and the inner sleeve are also parallel, with a clearance between the pipes 2, 3 and the inner sleeve.

[0050] The internal radial rib 12 is a support for the bearing 43 on which the inner sleeve 40 is placed. The internal radial rib 12 helps to adjust the position of the two pipes 2, 3, as well as to support the bearing 43.

[0051] Bearing 43 also provides a connection to the outside.

[0052] The inner sleeve 40 is preferably made of a sleeve material with a coefficient of expansion of zero or close to zero, or with the coefficient of expansion of the sleeve being very different from the thermoplastics used for fittings and pipes.

[0053] For example, the sleeve is made of carbon or fiberglass, that is, a stable material not subject to expansion or cracking. The coefficient of expansion of a carbon composite is in the range of 0.66 to 0.85 x 10⁻⁶ KL

[0054] The coefficient of expansion of a thermoplastic material is in the range of 65 to 200 x 10⁻⁶ KL

[0055] It should be noted that the play 9 between the inner sleeve 40 and the pipes 2, 3 allows a relative movement of the inner sleeve 40 and the two pipes 2, 3. This is important to take into account the different expansion behaviors of the pipes, the fitting and the inner sleeve.

[0056] The second solenoid 45 can be molded into the inner sleeve 40.

[0057] An electrical connection 32 is provided for the electrical connection with The external solenoid 30. The electrical connection 32 can be connected to a power supply (not shown). The power supply is an alternating current source. The alternating current passing through the first solenoid 30 can generate a magnetic field B1 in the connection. The magnetic field B1 is variable and generates an induced current I in the second solenoid 45 in the internal sleeve 40. In other words, a transformer is formed by the combination of the first and second solenoids.

[0058] The induced current I is modified according to the stresses to which the second solenoid is subjected. These stresses reflect the mechanical states of the first and second pipes 2, 3 and the main fitting body 10. For example, the induced current varies according to, among other things, stresses on the first pipe, second pipe and / or main fitting body, such as misalignment, thermal expansion, cracks, of / on the first pipe, expansion of the second pipe, expansion of the main fitting body.

[0059] An external measuring device 50 is provided to measure the induced current I. It should be noted that the induced current is transmitted to the measuring device 50 via a connection cable 53. Bearing 43 provides a connection and can allow the connection cable 53 to pass through it, for connection with instrumentation.

[0060] At least one strain gauge 55 is provided on the outside of the main fitting body 10. At least one strain gauge 55 is provided to measure a strain applied on the first and second pipes and / or the main fitting body.

[0061] As illustrated in [Fig. 3], a microcontroller 60 can be provided to control the strain gauge 55, and optionally the power supply for the electrical connection 32, for the deformation analysis of the main fitting body 10 and / or the pipes 2, 3 inserted therein. The measured current and strain data can be sent to a monitoring system 80, via the microcontroller 60.

[0062] The microcontroller 60 can be positioned on the main connector body 10 or remotely. The microcontroller 60 may include a data acquisition module, memory, and a communication module with connection capabilities for sending data to a monitoring module 70 of a monitoring system 80.

[0063] The monitoring module 70 is in communication with the microcontroller 60. The microcontroller 60 can be connected to the monitoring module 70 by known means of communication such as an Ethernet or PoE (Power Over Ethernet) cable, a coaxial cable, a fiber optic cable, an Internet modem, Wi-Fi, a 3G / 4G / 5G connection, Bluetooth, LiFi, infrared, an SPI link, a DSL cable or a USB cable.

[0064] The monitoring system 80 can activate at least one display mode to produce at least one display indicating information on current values ​​and / or network status, and an alert mode to produce an alert on current values ​​and / or network status. The monitoring system 80 can also activate a control mode to send control signals to the microcontroller 60 to operate the strain gauge 55 or to supply power to the first or second solenoid.

[0065] A fluid supply network may include a plurality of fittings 1, with a plurality of microcontrollers 60, connected to the monitoring system 80, for example via Bluetooth managed by a communication module 65.

[0066] An interface module 82 can be provided to manage physical interactions with a user. The interface module 82 can also manage a monitor system screen 80, control indicator lights and wake up the microcontroller 60 when display buttons on the screen are pressed.

[0067] In a non-limiting example, the plurality of microcontrollers 60 is connected to at least one aggregator in order to collect the data acquired by the microcontrollers 60. One or more aggregators may collect data from a part of the fluid distribution network. The data collected by one or more aggregators is transmitted to a monitoring module.

[0068] More specifically, the monitoring system 80 is adapted to receive the measured induced current I and stress data from the plurality of strain gauges 55, and to correlate the measured induced current I with stress data from the strain gauges 55, making it possible to characterize, at least in part, the mechanical states of the first and second pipes 2, 3 and the main fitting body 10, and of the fitting and pipe assembly. It is then possible to derive potential breaking limits.

[0069] This allows us to assess the current condition of the fitting and / or pipes.

[0070] In addition, the monitoring system 80 can perform predictive maintenance, based on historical records of collected detection data.

[0071] It is noted that the fitting 1 can be an electrofusion fitting designed to allow the electrofusion assembly of the main fitting body 10 with the pipes. In this case, an electrofusion wire, such as a helical spring, is embedded in a pre-stressed state within the main fitting body. The electrofusion wire is an electrical conductor that, during the welding operation, heats and melts the material surrounding the wire. In this case, the electrofusion wire 30, after the fitting is assembled with the pipe, can be used as the first solenoid 30.

[0072] Figure 4 shows a fitting 100 from another perspective. The main difference with the fitting in Figure 1 is that the fitting 100 has a second solenoid 145 placed in an external sleeve 140, instead of having a second solenoid placed in an internal sleeve.

[0073] It is important that the external sleeve 140 be grounded to an external reference 248 which is fixed, i.e. which does not move with the pipe.

[0074] As with the fitting in [Fig.1], the fitting body is made of a thermoplastic material while the outer sleeve is made of carbon or fiberglass, for example, a stable material.

[0075] It should be noted that there is a space or gap 109 between the main body 110 of the fitting and the outer sleeve 140, to ensure that the outer sleeve does not stick to the fitting.

[0076] It is noted that the parallelism of the first solenoid 30 and the second solenoid 45, 145 is important for the reliability and efficiency of a transformer.

[0077] The first solenoid 30, 130 preferably extends along an extension direction of the main connecting body 10, 100. The second solenoid 45, 145 preferably extends along an extension direction of the inner sleeve 40, respectively of the outer sleeve 140.

[0078] The inner sleeve 40 or the outer sleeve 140 are parallel to the main connecting body 10, 110, and thus are parallel to the pipe inserted into it.

[0079] The fitting and transformer device made of the first and second solenoids can be calibrated during installation, to take into account a misalignment of the first and second solenoids.

[0080] Similarly, an overlap of the first and second solenoids 30, 45 allows for reliable results. The principle is that the number of overlapping windings (turns) will change with the temperature and / or the elongation of the pipe.

[0081] It should be noted that having an internal solenoid smaller than the external solenoid ensures that the generated magnetic field is of better quality, as the magnetic field is well aligned with the pipe axis away from the ends. In a real transformer, the magnetic field lines are generally aligned using a steel core. Therefore, in the embodiments of Figures 1 and 2, the first solenoid 30 embedded in the fitting 1 is longer than the second solenoid 45 in the internal sleeve 40. In the embodiment of [Fig. 4], the first solenoid 30 embedded in the fitting 1 is shorter than the second solenoid 45 in the external sleeve 140.

[0082] In [Fig. 1], all the turns of the second solenoid 45, located in the inner sleeve 40, are used in the expansion characterization. All the turns of the first solenoid 30, located in the fitting, are used to generate a magnetic field. Only the overlapping turns are used in the transformer's "conservation rate," which depends on the thermal expansion or mechanical elongation of the pipe.

[0083] It should be noted that the magnetic field is uniform in the region where the inner sleeve 40 is placed in the [Fig.1].

[0084] In [Fig. 4], all the turns of the first solenoid 130, located in the connecting body 110, are used in the expansion characterization. All the turns of the second solenoid 145, located in the outer sleeve 140, are used to generate a magnetic field. Only the overlapping turns are used in the transformer conservation rate, which depends on the thermal expansion or mechanical elongation of the pipe.

[0085] Of course, the roles of the first and second solenoids can be reversed. However, in this case, the induced current is of poor quality because the magnetic field generated outside the inner sleeve 40 in [Fig.1] or outside the fitting in [Fig.4] is not well organized, i.e. not aligned with the axis of the fitting.

[0086] It is noted that the pipe can be inserted into the first pipe insertion space of the fitting, up to the radial rib 12. The internal sleeve 40 can be pre-assembled / inserted inside the pipe before inserting the pipe into fitting 1, or the internal sleeve 40 can be inserted into the pipe already in place in fitting 1.

[0087] The axial position of the inner sleeve 40, or of the outer sleeve 140, can be adjusted relative to the fitting 1 and / or the pipe. To correctly position the inner sleeve 40, the inner sleeve 40 may be provided with marking or positioning elements 47 indicating the median axial position and / or the median longitudinal position of the inner sleeve 40. The positioning elements 47 allow for correct positioning of the inner sleeve 40 in the pipe and in the fitting 1.

[0088] In addition, whenever the fitting 1, 101 connects two pipes, the inner sleeve 40, respectively the outer sleeve 140, is positioned so that the axial midpoint of the inner sleeve 40 is axially aligned with the internal radial rib 12 of the fitting 1. This allows a balanced measurement on the pipes and the fitting 1.

[0089] It is noted that the transformer formed by the two solenoids can be used for non-intrusive monitoring of the connection to the pipe(s), but also for monitoring / maintenance of the fluid flowing through the connection. For example, the transformer can be used to power a UV / LED system for UV detection and fluid characterization.

[0090] The present invention has been disclosed with a straight fitting. For different pipe arrangements, the fittings could also be designed as curved, angled or T-shaped pieces, generally with one, two or three connecting pieces being provided, as long as the solenoids are aligned for the transformer effect.

[0091] The above description of preferred embodiments of the disclosure has been provided for illustrative and descriptive purposes only. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from the practice of the invention. The embodiment has been chosen and described to explain the principles of the invention and its practical application to enable a person skilled in the art to use the invention in various embodiments that are suitable for the particular intended use. It is anticipated that the scope of the invention will be defined by the accompanying claims and their equivalents.

Claims

Demands

1. Fitting (1; 101) for connecting a pipe in a fluid supply network, comprising a main fitting body (10; 110) having a pipe insertion space (20a, 20b) extending in an axial direction XX, between an open end (1a, 11b) and an internal radial rib (12) extending radially inward from an internal body surface (15) and provided for stopping a pipe inserted into the main fitting body (10), a first electromagnetic device (30; 130) arranged in or on the main fitting body (10; 110) and extending parallel to the main fitting body, a second electromagnetic device (40;140) extending parallel to the main connecting body and arranged with a clearance with the main connecting body, in which the first electromagnetic device and the second electromagnetic device provide an electromagnetic interaction between them representative of a current mechanical state of the connection.;

2. Fitting according to claim 1, wherein the first electromagnetic device (30; 130) comprises at least one first solenoid and the second electromagnetic device comprises at least one second solenoid (45; 145).

3. Fitting according to claim 2, wherein the fitting is an electrofusion device and the electrofusion wire is the first solenoid.

4. Fitting according to any one of the preceding claims, wherein the second electromagnetic device is placed in an internal sleeve (40) positioned inside the fitting, preferably flush with the free end of the radial rib (12).

5. Fitting according to claim 4, wherein the inner sleeve (40) is positioned on a bearing (43) at the free end of the radial rib (12).

6. Fitting according to claim 4 or 5, wherein the inner sleeve (40) is arranged inside the fitting, so that, in operation, the second electromagnetic device is arranged inside a pipe inserted into the main fitting body.

7. Fitting according to any one of claims 1 to 3, wherein the second electromagnetic device is placed in an external sleeve (140) positioned outside the fitting, preferably with a clearance with the fitting.

8. Fitting according to claim 7, wherein the outer sleeve (140) is grounded to an external reference.

9. Fitting according to any one of claims 4 or 7, wherein the inner sleeve (40) or the outer sleeve (140) is made of a thermally stable material, such as carbon or fiberglass.

10. Fitting according to any one of claims 1 to 9, comprising at least one strain gauge (55) on an external body surface of the main fitting body (10).

11. Fitting according to any one of claims 1 to 10, provided with a connection (32) that can be connected to a power supply as an alternating current source, and / or with a connecting cable (53) that can be connected to a measuring device (50) to deliver an induced current.

12. Fitting assembly comprising a fitting (1; 101) according to any one of the preceding claims connecting a first pipe (2) and a second pipe (3), and a power supply for providing alternating current to one of the first electromagnetic device or the second electromagnetic device, for generating a magnetic field, and a measuring device (50) provided for measuring an induced current in one of the first electromagnetic device or the second electromagnetic device.

13. Connection assembly according to claim 12, with a monitoring system (80) and a microcontroller (60) for sending measured current and strain data to a monitoring system (80) and / or receiving instruction signals from the monitoring system.

14. A method for monitoring / diagnosing / characterizing a connection assembly according to claim 13, comprising: - supplying an alternating current to one of the first electromagnetic device or the second electromagnetic device, to generate a magnetic field, - measuring a current induced in the other of the first electromagnetic device and the second electromagnetic device,

15. - the derivation of a current mechanical state of the fitting on the basis of the measured induced current, in which the current mechanical state includes information concerning stresses on the first pipe, the second pipe and / or the main fitting body, such as misalignment, thermal expansion, cracks, of / on the first pipe, expansion of the second pipe, expansion of the main fitting body. Method according to claim 14, comprising the operation of a strain gauge to obtain stress data applied to the first and second pipes and / or the main fitting body, and the correlation of the induced current and the stress data to derive the current mechanical state of the fitting.

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