Electromagnetic device and methods for checking pipe continuity, pressure and calibration

Abstract

The invention relates to an electromagnetic device (60) for checking pipe continuity, pressure and calibration in piping, which comprises a resonant circuit (65), the resonance frequency of which varies when the pressure exceeds a predetermined threshold; and a first piece (61) with two openings (611, 612) that are connected inside the device by an internal pipe (81) with a hole that allows the passage of air through a channel (82) to a membrane (62), the membrane deforming when the pressure increases and transmitting the increase to a pressure-sensitive element of the resonant circuit. The device is connected to two ends of pipes of piping for a fibre network and has two different resonance frequencies according to the pressure inside the pipe. The associated methods enable fast, precise, repeated and auditable testing in fibre optic networks.

Description

[0001] ELECTROMAGNETIC DEVICE AND METHODS FOR VERIFYING CONTINUITY, PRESSURE AND CALIBRATION OF DUCTS

[0002] DESCRIPTION

[0003] Object of the invention

[0004] The present invention has application in the technical sector of fiber optic telecommunications and, in particular, presents a technical solution for carrying out verification of pressure, calibration and continuity tests in a network of buried conduits (for example, microducts), by means of an electromagnetic device (beacon), which also allows the detection of the tip of the buried microducts.

[0005] Background of the invention

[0006] Fiber optic data distribution networks are increasingly being used to provide broadband data connections to users. In some scenarios, due to the lack of available infrastructure for new fiber optic cable runs, it is becoming necessary to construct new pipelines for subsequent fiber optic deployments. The construction of these new pipelines often requires the construction of new trenches (civil engineering), which increases deployment costs. For this reason, the use of microducts is a clear trend to minimize trench sizes and, therefore, deployment costs. Microducts are fiber optic transport tubes that are much smaller than traditional ones (microducts typically measure between 5 and 20 mm in diameter).

[0007] It is also quite common in some countries to deploy fiber optic manholes or intermediate registers without installing them, or with a very small number of them (for example, to minimize costs, expedite permitting with government agencies, etc.). This means that rapid access to fiber optic conduits will not be possible in the future, making maintenance and operation difficult, as in many cases only the two ends of the conduit are available / accessible. Therefore, signaling the conduit and recording its route are especially important, as it is necessary to know precisely where the conduit runs in case a repair is necessary.

[0008] For example, it is very common to use electromagnetic devices (called beacons due to their signaling function) buried at certain intervals along a pipeline route. By placing these devices, it is possible to detect where the pipeline runs in the future using a simple beacon detector. This type of beacon is also commonly used to mark specific points in the fiber optic network (branches, splices, or connections, etc.). These beacons are not only used in telecommunications pipelines but are also used in other fields (water, energy, gas, and sanitary pipelines, etc.).

[0009] Fiber optic networks are named differently depending on where they end, so we would have, for example: fiber to the building (FTTB) or fiber to the home (FTTH).

[0010] It's common for any new FTTH network to have different sections from the operator's head office (or point of presence) to customers' homes. Although this classification is not standardized, it can be divided into three clearly differentiated sections: feeder network, distribution network, and dispersion network or service connection. The feeder network typically runs from a head office or point of presence (PDP) to a distribution point (DP). A distribution point can serve N properties and therefore typically concentrates a number of connections on the distribution side and reduces them to a single cable or two leading to the feeder network. The distribution network is the section that runs from the distribution point (DP) to the final segregation of the service connection, which would then form part of the dispersion section or service connection.The dispersion or service connection network extends, within the private domain of each home / property, from the final segregation made from the distribution network (shared by several properties) to each home / property (dedicated service connection). This can be clearly seen graphically in Figure 1, which shows a basic diagram of the FTTH network. In fiber optic networks, the concept of passed homes is used. These are those homes (domiciles) covered by a provider's fiber optic network in a given area or, in other words, homes that can potentially be connected to the fiber optic network in an area if their owners subscribe to the service because the fiber optic network is deployed in that area.It's quite common, during the deployment phase (when referring to homes that have been passed through), for the service connection section (dispersion network) not to be deployed, and for this to be done only when the customer is fully connected, once the fiber optic service has been contracted (that is, when the customer is not simply a home passed through a provider's network, but a home that has contracted the service from that provider and is connected to its network). In certain cases, a partial service connection may be deployed to reduce the connection costs for each customer in the future (when they want to connect to the network). This type of partial deployment is commonly referred to as Home Passed Plus (HP+), or also FTTF (Fiber To The Fence).These concepts generally cover cases where fiber is brought to the fence, but also where the conduit (physical infrastructure of the fiber optic network) reaches the property's fence. Figure 1 shows where the FTTF point would be located in the basic network diagram shown.

[0011] All network sections are inventoried and are eligible for marking with electromagnetic beacons at the discretion of each operator. However, specific points where future action is expected to be required are points where the use of electromagnetic beacons is most appropriate, as it is more likely that that point will need to be accessed in the future. One of the specific points that is eligible for marking with electromagnetic beacons (and in fact, it is a common practice in the deployments of numerous operators in Europe) are the points where the customer connection is segregated from the distribution network, and also, more specifically, the point where the connection that will later serve the property is buried (the FTTF or HP+ point).

[0012] The location of this point must be recorded with high precision and must also be easily located in the future, since on the day the property owner finally contracts the service, this point must be used as the starting point to continue with the final section of the connection to the interior of the home. Given the importance of correctly locating these points, it is very common to record the exact location of the FTTF or HP+ point with GPS coordinates (usually requiring centimeter precision). It is also quite common to install an electromagnetic beacon at this point to allow location with a simple beacon detector, instead of requiring a high-precision GPS.

[0013] This can be clearly seen in Figure 2, which shows a scenario in which an electromagnetic beacon is used to signal the FTTF point in an individual segregation or, in other words, to signal the end of a service entrance microduct through which the home will be connected to the fiber optic network when service is to be provided to that home. To do this, the service entrance microduct is connected at one end by a connector to the corresponding microduct in the distribution network, and at the other end, it is connected to the electromagnetic beacon by a connector that will signal that point. The other end of the distribution network microduct is normally closed with a plug, as shown in the figure.

[0014] The FTTF point is just one example of a “singular” point that is beaconed in a fiber optic network, but there may be many other types of network points that, for one reason or another, need to be located and therefore may need to be beaconed in a fiber optic network.

[0015] There are different types of location beacons for these functions. There are many types of beacons, but only some of the most common types available on the market will be mentioned here:

[0016] • Ball-type beacons. This type of beacon can typically be detected at depths of between 2 and 3 meters (depending on the manufacturer and model). They usually include a mechanism that guarantees detection accuracy, regardless of how the beacon is installed (the resonant circuit is designed to emit signals perpendicular to the surface, and the beacon contains the necessary means for this: self-leveling system, fluids, etc.). • Flat plate-type beacons. This type of beacon can be detected at depths of between 2 and 3 meters, as long as it is installed in the correct position.

[0017] • Cylindrical beacons. These are cylindrical beacons that can be detected at a depth of between 2 and 3 meters if installed vertically and at a maximum depth of approximately 0.6 meters if installed horizontally (i.e., they are designed to have a longer range if installed vertically).

[0018] All of these locator beacons typically incorporate a completely passive resonant circuit (usually a ferhta-core coil and capacitor), which is detectable when excited by an electromagnetic signal at the appropriate frequency (depending on the type of buried service, a different frequency is usually used). This is what a beacon detector does: it emits an electromagnetic signal at the desired resonant frequency (or a range of frequencies including the desired resonant frequency), and the presence of a beacon is determined at the point where it detects a return signal at that frequency (from the beacon's resonant circuit).

[0019] Depending on the application and the circumstances of the associated work, one type of beacon may be more suitable than another. Due to their physical shape, some beacons require more space for installation than others. For this reason, the beacon with the best performance may not necessarily be the most appropriate for a specific application. For example, in the case of the FTTF or HP+ points mentioned above, minimally invasive techniques may be used for their execution (e.g., a drill hole with a diameter less than 25 mm), allowing the installation of a pointed microduct from the distribution network segregation to the desired FTTF or HP+ point. These types of techniques offer many advantages during execution, as they are very quick to perform, do not damage the ground surface (street / sidewalk / garden), and do not require compacting the ground to install this small cable.However, these types of techniques do not allow the use of ball- or plate-type beacons, nor cylindrical beacons installed vertically, because their size prevents them from fitting through the hole. Therefore, horizontally installed cylindrical beacons are more useful in these cases. This is because the hole is drilled horizontally into a trench wall (in a real-life example, the horizontal hole may be 25 mm in diameter and about 50 cm long); therefore, it is easier for a horizontal beacon, following the direction of the microduct, to fit than a vertical one. Using horizontally installed cylindrical beacons reduces the depth at which they can be detected.However, in the last sections of the network, it is common to deploy pipelines (microducts) at depths ranging from 15 cm to 60 cm (greater depths are not common), so this type of beacon is perfectly valid.

[0020] There are solutions on the market for horizontally installing beacons, according to the aforementioned application. There are solutions that allow these beacons to be placed at the end of a microduct, making them ideal for installation in situations such as the one explained above (executing an FTTF or HP+ system using the drill-hole drilling technique). There are different versions of the same solution concept that implement the connection between the beacon and the microduct in different ways: there are models with direct connection to the microduct (guaranteeing watertightness and quick fixation with standard fittings / connection means) and others with indirect connections through a rubber sleeve that allows the beacon to be secured to the microduct, previously sealed with a standard plug.

[0021] The inventory and marking of points of interest in a fiber optic conduit (for easy detection) is therefore clearly resolved using materials available on the market.

[0022] However, when installing a conduit (for example, a fiber optic network), in addition to marking certain points of interest (as explained above), it is necessary to ensure the quality of the conduit. In the case of a conduit using microducts, three main types of tests are typically performed:

[0023] • Continuity verification test (also called route verification). This is an end-to-end test that ensures that the branches have been made correctly and in accordance with the project plans. It is common to use microducts of different colors, and during deployment, there is always a risk of confusing colors when making the different branches, causing the actual configuration to not match the plan (i.e., the actual layout or route of a microduct may not be correct), and therefore, it must be tested.

[0024] • Pressure test. This test ensures that all connections made in a route between different microducts are leak-tight and meet quality standards. It also checks the microducts for permanent damage such as cracks or fissures.

[0025] • Calibration test. This test is intended to ensure that the microducts in a route maintain a minimum internal diameter, allowing cables with a diameter equal to or smaller than the one tested. This is a very important test, since during civil engineering construction, microducts can be damaged by impacts or crushing, usually due to poor trench preparation (lining and sand bed, etc.) or excessive pressure during soil compaction. These impacts or crushing events can reduce the available diameter inside the microduct at that point, making it impossible for the fiber optic cable to pass through that point, making it impossible to deploy the fiber optic network.

[0026] For the pressure test, it's enough to have only one end of the duct (microduct) free, into which air can be introduced into the circuit until the desired pressure is reached. A pressure gauge (at the same end) can be used to measure whether there is any pressure drop or loss, since the other end will be blocked and does not require access to verify the test. That is, at the same end where the air is introduced, a measurement can be made as to whether or not there is a loss of pressure in the circuit. However, for the continuity verification test, up to now, both ends of the duct must be open, one to introduce the air and the other to verify that the air is exiting where it should (that is, that the connections between the different microducts have been made correctly, without mixing them up); and thus verify, from the distribution point to the customer, that everything is correct.For the calibration test, a gauge (mandrel type) is required. It is inserted at one end and the other must be open to remove it and verify that everything is correct (the internal diameter of the microduct is undamaged). Therefore, with existing methods, both ends of the microduct must also be accessible.

[0027] Performing these tests is essential to ensure that the channeling is correct, as any such failure would prevent the fiber optic network from deploying and functioning properly.

[0028] However, on the other hand, performing these tests is quite time-consuming and, in most cases (except for pressure testing), requires access to both ends of the pipeline being tested (essential for continuity and calibration verification tests). Therefore, if manholes or inspection chambers are unavailable, open holes must be provided at the end points of the pipelines being tested. Keeping the holes open continuously or indefinitely is practically impossible for safety reasons and public administration permits. Opening the holes every time testing is necessary may also be impossible due to permit issues and is very costly and time-consuming due to the amount of work required.

[0029] For these reasons, these types of tests are often performed during the execution of civil works for the installation of pipelines. The problem is that these tests slow down the pace of the project (pressure and calibration tests require a considerable amount of time), and for this reason, many contractors are reluctant to perform them completely, and some are often performed only partially (continuity verification tests and rapid pressure tests). Furthermore, even if these tests are performed partially, they cannot be audited or repeated in a meaningful way due to the difficulties explained above. Therefore, for the operator who commissions the pipeline installation, it ends up being a leap of faith to determine whether the pipelines have been installed in perfect condition or not.Therefore, there is a need for a technical solution capable of minimizing the time and resource costs of these tests, while still allowing them to be performed accurately, as they are essential for the proper functioning of the pipeline.

[0030] Summary of the invention

[0031] The present invention addresses the aforementioned problems by means of a novel electromagnetic beacon that not only identifies the location of one end of a fiber optic conduit duct to which it is connected, but also allows for continuity, pressure, and calibration verification tests to be performed on a fiber optic conduit duct, in an improved manner compared to existing procedures. Typically, such fiber optic conduits will be microducts.

[0032] Thus, the present invention provides a new electromagnetic device (also called a beacon due to its signaling function) and measurement methods that allow, through the use of this device, to perform continuity, pressure and calibration verification tests on a conduit pipeline (microducts), quickly, accurately, repetitively and auditably.

[0033] To perform the calibration test, access to both ends of the pipeline to be tested is required. As previously mentioned, access to one end is quite common at the network distribution point. At the opposite end, access to the end of each microduct (the FTTF or HP+ point) would also be necessary to perform the calibration test. However, the device and method of this invention allow the calibration test to be performed without requiring individual access points for each of the microducts to be tested. Instead, with a single access point (manhole, manhole, or pit), the calibration of all the microducts running through the same pipeline could be tested (even if there are partial segregations of service connections made along the route).The present invention also saves resources and time since, among other things, the calibration test only requires access to both ends of the pipeline. That is, one of these access points will be the network distribution point, and the other access point will be the end point of the pipeline (which is shared by both microducts to be tested), without the need to have access to each test point (the FTTF or HP+ point, where the beacon is buried). And as explained later, continuity and pressure tests can be performed without access to both ends of the microduct. Therefore, in most cases, there is no need to drill holes to perform these tests.

[0034] Specifically, in a first aspect of this invention, an electromagnetic device is presented for verifying continuity, pressure and calibration in conduits of a pipeline, which comprises:

[0035] - A resonant circuit whose resonant frequency varies from a first frequency, fi, to a second frequency, Í2, when the pressure in a pressure-sensitive element of the resonant circuit is greater than a first predetermined pressure threshold;

[0036] - Two openings at one end of the electromagnetic device, each opening being designed to connect to one end of a raceway conduit (e.g., each opening is physically shaped to connect to a raceway conduit via a standard connector or has appropriate means to connect to a raceway conduit);

[0037] - An internal duct connecting, within the beacon, the two openings, where said internal duct has a hole (which allows the transmission of air from the openings to the interior of the beacon);

[0038] - A housing (which houses and protects the resonant circuit).

[0039] In one embodiment, the resonant circuit includes two capacitors in parallel, connected by one of their ends to a pressure-activated switch (pressure-sensitive element), which closes when the pressure received by said switch is greater than the first predetermined pressure threshold or where the resonant circuit includes a capacitor (pressure-sensitive element) whose capacitance changes value when the pressure it receives is greater than the first predetermined pressure threshold or where the resonant circuit includes a coil (pressure-sensitive element) whose inductance changes value when the pressure it receives is greater than the first predetermined pressure threshold.

[0040] In one embodiment, when the beacon is connected to two ends of pipeline conduits via openings thereof, the pressure across the pressure-sensitive resonant circuit element is dependent upon the pressure received (e.g., pressurized air is received) at the end of one of the conduits to which the electromagnetic device is connected. The first predetermined pressure threshold is typically high enough such that the pressure across the pressure-sensitive element (which is dependent upon the pressure received from one of the pipeline conduits to which it is connected) only reaches or exceeds that threshold when there are no leaks in the pipeline layout for that conduit.

[0041] In one embodiment, where the device comprises a first piece where the two openings and the internal duct are located, where the hole of the internal duct allows the passage of air through a channel, to a pressure measuring chamber located between this first piece and a membrane and where this membrane deforms when the pressure in the chamber increases and transmits said pressure increase to the pressure-sensitive resonant circuit element (in this way the pressurized air that has entered through one of the ends of one of the ducts and that reaches the beacon, is transmitted to the resonant circuit so that it passes from one frequency to another).

[0042] The device may also comprise a second part secured to the first part by a retention system, where the membrane is located between both parts (or within the second part) and where this second part is secured to the housing. The connection between the first and second parts can be made by means of a retention system that can withstand pressures of, for example, up to 16 bars. Thus, the first and second parts, and the second part and the housing, can be joined, for example, by a retention system, such as a screw connection or a bayonet fitting. In one embodiment, each of the openings has a cylindrical shape and an external diameter suitable for connection to the pipeline conduit of standard dimensions (for example, through a standard conduit connector).

[0043] In one embodiment, the conduit is a fiber optic network conduit and the conduits to which the device connects are microducts.

[0044] In a second aspect of this invention, a method is presented for performing calibration tests on conduits of a pipeline (for example, a pipeline of a fiber optic network), using the electromagnetic device described above, where the method comprises: a) Connecting in a hermetic manner, one of the openings of the electromagnetic device to one end of a first conduit of the pipeline and another of the openings to one end of a second conduit of the pipeline; b) Introducing a piece with a predetermined caliber through the other end of the first conduit (the end not connected to the device, which can be located for example at a distribution point of the fiber optic network) together with pressurized air; c) If the piece exits through the end of the second conduit (the one not connected to the beacon), then determining that the result of the calibration test performed is positive;that is, the first (and second) conduit has sufficient internal diameter (that of the gauge piece) throughout its length (for example, sufficient diameter to be able to pass the fiber optic cable).;

[0045] The device described, in addition to calibration tests, also allows for continuity and pressure verification tests. Therefore, this invention also presents a method for performing continuity verification tests and pressure tests on conduits in a pipeline (for example, a fiber optic network pipeline), using the electromagnetic device described above.Wherein the method comprises: a) Tightly connecting one of the openings of the electromagnetic device to one end of a first conduit of the pipeline and another of the openings to one end of a second conduit of the pipeline (this step is the same as step a) of the method for carrying out the calibration tests); b) Introducing pressurized air through the other end of the first conduit (the end not connected to the device, which may be located, for example, at a distribution point of the optical fiber network); c) Detecting the resonant frequency of the electromagnetic device and, if the resonant frequency has changed with respect to the resonant frequency of the device in the absence of pressurized air (i.e., it is not h but Í2), then determining that the result of the test carried out (continuity and / or pressure verification) is positive.

[0046] These continuity and pressure tests can be performed, for example, before or after the calibration tests. Thus, the two methods presented can be combined into a single method, in which steps b) and c) of the first method (for performing the calibration tests) are performed after step a) (common to both methods), and steps b) and c) of the second method (for performing the pressure and continuity tests) are performed after (or before) step b) and c) of the second method.

[0047] In one embodiment, the pressure across the pressure-sensitive resonant circuit element depends on the pressure received by the end of the first conduit to which the electromagnetic device is connected, and where, in order to perform the pressure test at the same time as the continuity verification test, the first predetermined pressure threshold is sufficiently high (for example, sufficiently high such that the pressure across the pressure-sensitive element reaches that threshold when there are no significant leaks in the pipeline layout and specifically in the first conduit). This threshold may be, for example, 8 bars. In this case, if in step c) the resonant frequency has changed with respect to the resonant frequency of the device in the absence of pressurized air, then it is determined that not only the result of the continuity verification test but also the result of the pressure test is positive.

[0048] In one embodiment, if the resonant frequency does not change in step c), then the pressure at the end of the conduit through which pressurized air is introduced can be measured to determine whether the pressure test or the continuity verification test has failed. In one embodiment of the methods (both the calibration testing method and the pressure and continuity testing method), the conduits to which the device is connected are microducts.

[0049] In one embodiment of the methods, step c) is performed with the ends of the conduits connected to the electromagnetic device and the electromagnetic device buried.

[0050] In one embodiment of the methods (both the method for calibration testing and the method for pressure and continuity testing), the conduit is a conduit of a fiber optic network and where the first conduit is a conduit that goes from the distribution point of the fiber optic network to the point of connection to a home, FTTF or HP+ point, and the second conduit is a conduit that goes from said point of connection to the end of the conduit bundle or end of line (or layout).

[0051] The scope of the present invention is defined by the appended independent and dependent claims. For a more complete understanding of the invention, its objects and advantages, reference may be made to the following specification and the accompanying drawings.

[0052] Brief description of the figures

[0053] Below, a very brief description is given of a series of drawings that help to better understand the invention and that are expressly related to an embodiment of said invention that is presented as a non-limiting example thereof.

[0054] FIGURE 1.- Shows schematically the different sections into which a FTTH fiber optic access network can be divided, locating the FTTF (or HP+) point in the private domain.

[0055] FIGURE 2.- Shows a schematic representation of a scenario where an FTTF point is signaled with an electromagnetic beacon. FIGURE 3.- Shows a schematic representation of the connection of the beacon proposed in the present invention to two microducts, according to an embodiment of the invention.

[0056] FIGURE 4.- Shows schematically a variable resonant circuit of the beacon, whose resonant frequency varies with pressure, according to an embodiment of the invention.

[0057] FIGURE 5A.- Shows schematically a scenario where beacons are connected in the state of the art.

[0058] FIGURE 5B.- Shows schematically a scenario where the beacons proposed in the present invention are connected to three different microducts at three different points of the network, according to an embodiment of the invention and the pressure and continuity test is performed for one of them.

[0059] FIGURE 5C.- Shows schematically a scenario where the beacons proposed in the present invention are connected to three different microducts at three different points of the network, according to an embodiment of the invention and the calibration test is performed for one of them.

[0060] FIGURE 6.- Shows an exploded view of the proposed beacon, according to an embodiment of the invention.

[0061] FIGURE 7.- Shows a view of the resonant circuit of the proposed beacon, according to an embodiment of the invention.

[0062] FIGURE 8.- Shows a sectional view (side) of the beacon, according to an embodiment of the invention.

[0063] FIGURE 9.- Shows a sectional (zenithal) view of the beacon, according to an embodiment of the invention.

[0064] FIGURE 10.- Shows a view of a standard connector for connecting microducts. Detailed description of the invention

[0065] Examples of embodiments of the invention are described in detail below, with reference made where necessary to the figures cited above, without limiting or reducing the scope of protection of the present invention.

[0066] The electromagnetic device (beacon) proposed in the present invention is resonant at different frequencies and is connected to two microducts (or more, although generally to two conduits) of a fiber optic conduit, so as to allow the location of a buried end of a conduit, in addition to allowing the verification and certification of the (micro)duct conduits by continuity, calibration and pressure.

[0067] The beacon is designed to be able to be connected (directly in one embodiment) to two conduits, typically two micro-ducts (better known as microducts), in a robust and completely sealed manner (there is no loss of pressure or airflow due to the connection of the beacon to the conduits). That is, the beacon must be able to connect to the microducts (in other words, be connectable to the microducts). To this end, in one embodiment, it will itself have the necessary means to connect to the microducts.However, in a preferred embodiment, the beacon will have the appropriate physical shape to be able to connect to the (micro)ducts and, specifically, it may have two accesses or openings (normally in the form of a tube) at one of its ends, with the appropriate shape to allow the (quick) connection to the microducts through the use of standard microduct connectors (as if it were a connection that provides continuity between 2 microducts, but in this case it will be between each microduct and the beacon). That is, in one embodiment, the beacon at one of its ends must have 2 openings (also called inlets) in the physical form of two ducts, each of the same or similar diameter as the microduct to which it is to be connected. In addition, it will have an internal connection (also called internal conduit or bypass circuit) that connects both inlets and that is wide enough to allow the passage of a calibration mechanism (mandrel) from one inlet to the other.

[0068] Figure 3 shows schematically said connection between two microducts (31, 32), two connectors (33, 34) and the marker beacon (35) object of this invention (on the right). Internally, the beacon performs a bypass circuit (36) interconnecting the two conduits (microducts) connected to it. Said bypass is an internal conduit / circuit that maintains at least the same internal diameter as the conduits to which it is connected and its shape, in one embodiment, is half of a toroid. In this way, it allows the passage of a calibrated mandrel (a ball chain, for example), from one microduct to the other.

[0069] In other words, the beacon has an internal conduit (36) that connects the two openings (37, 38) of the beacon, which in turn will each be connected to a microduct (when the beacon is installed in the pipeline network)

[0070] Furthermore, the beacon must have, in the internal conduit or bypass (36), an orifice that allows the pressure in the conduit to be tested to be measured. Said orifice, in one embodiment, is of a very small size and can be placed in the center of the bypass (or in any other position). Said orifice does not affect the passage of the mandrel, which will be used in the calibration test, but it will allow the passage of air into the beacon (and specifically into the resonant circuit so that the change in resonant frequency occurs, as will be explained later).

[0071] Therefore, this beacon will allow pressure tests and continuity verification to be carried out (as explained below) and, additionally, it allows the passage of a mandrel or ball chain from one pipe to another, allowing (with the appropriate procedure and setup) the calibration test of the microducts to be carried out.

[0072] Unlike existing beacons (whose circuits resonate at a single frequency), the beacon of the present invention incorporates a variable resonant circuit inside, which can resonate at least at two different frequencies: at rest it resonates at a first frequency fi, and when one of the conduits to which it is connected is subjected to a pressure greater than a threshold (Ui), it resonates at a frequency Í2. The way in which the frequency change is carried out may vary depending on the implementation.

[0073] A common implementation of a resonant circuit at a given frequency is a basic LC circuit, consisting of a coil (also called an inductor) and a capacitor in parallel. As is well known, the inductance of the coil (L) and the capacitance of the capacitor (C) define the frequency at which the assembly resonates, and is given by the following formula (where the frequency f is measured in hertz (Hz), the capacitance C in farads (F), and the inductance L in henries (H)):

[0074] By changing the value of one of the two elements, for example the capacitor, you can change the frequency at which it resonates. Thus, as can be seen in the formulas below, changing the value of the capacitor's capacitance (from Ci to C2, where C a is the difference in value between C2 and C1) we manage to change the resonance frequency (from C2 to C1).

[0075] This change in capacitor capacitance can be achieved in numerous ways. In one embodiment, for example, a pushbutton / switch can be used that is pressure-activated (when a pressure threshold is exceeded) and adds capacitance to the resonant circuit. This is shown in Figure 4, which presents a resonant circuit with two capacitors (with capacitances C1 and C2). a respectively) in parallel connected by a pressure-activated switch. Below a pressure threshold (Ui), the switch is not activated, so the circuit capacitance will be that of the first capacitor (C1) and, therefore, the resonant frequency of the circuit will be a first frequency (fi); when the pressure rises above this threshold, the switch closes so the circuit capacitance will be that of the two capacitors (C1 + C a) and therefore the resonant frequency of the circuit will be a second frequency (I2) different from the first. The circuit parameters (L, Ci, C a , Ui) are device design parameters that will be conveniently chosen depending on how it is intended to operate. Thus, for example, by conveniently choosing the circuit parameters, and specifically, the capacitances of the capacitors to be used, the circuit can be made to resonate at frequencies commonly used in commercial beacons to signal different services (as shown in the following table).

[0076] Thus, for example, the first frequency h could be used as the frequency used to mark buried telephone lines 101.4 kHz and the second frequency Í2 the one used to mark buried fiber optic lines 92 kHz. This is only a non-limiting example and other frequencies could be used depending on the services to be marked, the chosen criteria, etc. and, in general, by appropriately choosing the circuit parameters, it can resonate at the desired frequencies h and Í2 (for example, depending on the application where the beacon is to be used).

[0077] The pressure-activated switch / button can be of any type. It can be any standard commercial device actuated by another system that includes a displacement of a stem or membrane, but it can also be a standard pressure switch or any device that can fulfill the required functionality of being pressure-activated (or more generally, pressure-sensitive). A pressure-activated switch / button isn't even required, as a capacitor whose capacitance changes with pressure would also be suitable.In the embodiments shown above, changing the circuit's capacitance value has been used to vary the resonant frequency; however, changing the inductance value of the coil L instead of the capacitance of the capacitor C, in order to vary the resonant frequency with pressure, would also be possible and is a possible embodiment of the present invention; although in general, it could be more complicated to manufacture. In general, it should be noted that the resonant circuit shown in Figure 4 is only a non-limiting embodiment, and the proposed beacon could include any type of resonant circuit whose resonant frequency varies with the pressure received by the circuit (or more specifically, the pressure received or detected by one of the elements of the pressure-sensitive circuit).

[0078] As explained below, the placement of a beacon as described above allows for continuity, pressure, and calibration testing of pipelines in a novel and highly operationally and economically convenient manner. This is due, among other things, to the fact that it allows continuity and pressure verification tests to be performed without the need to have both ends open to perform the tests correctly. Additionally, it allows for simple calibration testing for various individual microduct segregations (partial connections, HP+, or FTTFs) from just two work points located at the common ends of the pipeline.

[0079] Performing pressure testing, continuity verification, and calibration using materials currently available on the market is a very costly process. There are basically two options: performing it during the execution of the civil works or after the fact.

[0080] If tests are performed during deployment (at the same time as the civil works are being carried out with open trenches), the work pace of the civil works operators is slowed down. Furthermore, it requires more specialized personnel to perform the tests and collect and interpret the results. If the tests are performed after the fact, then holes or test pits (at a significant cost) must be drilled to access both ends of the pipeline to be tested (one is usually available at the distribution point, but the other end is usually buried, as it is the FTTF or HP+ point). Leaving the holes open indefinitely throughout the deployment period is practically unfeasible.

[0081] However, with the beacon described in this invention, which changes frequency with pressure and has a bypass for receiving the calibration mandrel, it is possible to carry out all the tests in a simple, fast and precise manner, without having to slow down the pace of the work and without having to open several holes afterwards to carry out the tests.

[0082] Continuity and pressure verification tests.

[0083] To perform the continuity verification test, with one end of the pipeline available (for example, at the distribution point), it is possible to apply pressure to each of the conduits independently, and with a standard detector verify (without having to make any holes) that the conduit being tested reaches the desired location (at the end of the microduct where the beacon is), since, at that location and when pressure is introduced into the circuit at the other end, the resonant frequency of the beacon will change temporarily (until the pressure is removed).

[0084] That is, if the actual route of the duct is not correct, the pressure would not reach the beacon located at the other end of the duct (for example, at the FTTF or HP+ point), and it would not change its resonant frequency; if the actual route of the duct is correct, the pressure reaches the beacon, and it changes its resonant frequency. Therefore, with a beacon detector at the beacon position (end of the duct), the continuity check could be easily performed: if when applying pressure at the other end of the duct, the resonant frequency remains at the first frequency, then the continuity check test is negative (the microduct route is not correct); and if when applying pressure at the other end of the duct, the resonant frequency changes to the second frequency, the continuity check test is positive (the microduct route is correct).Pressure testing can also be performed this way, as the beacon can be designed or calibrated to only change frequency at a sufficiently high pressure, ensuring there are no leaks in the rest of the pipeline (since, if there were, the correct pressure would never be reached at the beacon and there would be no change in resonant frequency). Therefore, if the beacon changes resonant frequency when pressure is applied, it means the microduct connections are watertight and there are no significant cracks or fissures.

[0085] Thus, whether the pressure test can be performed in conjunction with the continuity verification test will depend on the pressure threshold of the beacon, or more specifically the pressure threshold (at the end of the conduit) above which the resonant frequency of the beacon connected to the conduit changes.

[0086] If this pressure threshold is low, for example 0.5-1 bar, then network continuity may be verified, but it would not be sufficient to guarantee network quality with the pressure test (i.e., if the beacon changes frequency, continuity could be verified, but the pressure test cannot be guaranteed to be successful). If this threshold is high enough (for example, 8 bars), both tests could be considered passed if the beacon changes frequency (since the threshold for which the beacon is designed is sufficient to guarantee the pressure test).

[0087] In other words, if pressure is applied to one end of the conduit and the beacon (at the other end) is found to have changed frequency, it indicates that the continuity verification test is successful, but it will only also indicate that the pressure test is successful if the beacon pressure threshold is high enough.

[0088] However, if pressure is applied and the beacon is found to have not changed frequency, then it is known that there has been a continuity or pressure fault, but a priori, it will not be possible to determine which of the two causes (lack of continuity or a lack of tightness in the network) is the culprit. That is, if the threshold is high enough and the beacon does not change frequency, then there may be a fault that could be either continuity or pressure. However, in the event of a failure (the resonant frequency does not change), it would be possible to verify whether the pressure test was correct, since the pressure could be checked from the end from which the pressure is applied (with a standard pressure gauge) and therefore determine the reason why the beacon is not activating (if the pressure gauge indicates that the pressure is correct, then it would be a continuity fault).

[0089] Calibration test.

[0090] In order to perform the calibration test in a joint manner (operationally viable), the ducts to be tested are provided with continuity up to a common point located at the end of the pipeline or line, as explained below.

[0091] Normally, the distribution network leaves the distribution points in groups or bundles of microducts (54) that are installed buried in trenches that run in front of the properties they are intended to serve. When an HP+ or FTTF installation is carried out, what is carried out is an individual segregation of one of the microducts contained within that group or bundle of microducts towards the property (towards the FTTF point). To do this, one of the microducts from the bundle is extracted (segregated), and an individual connection is made that carries the fiber towards the property (towards the FTTF point). In this way, an individualized microduct layout is obtained from the FTTF point to the distribution point. This type of segregation is carried out recurringly for each property that is covered. The bundle runs along the entire route (for example, a street or group of streets) from start to finish, and the segregations are made at the corresponding height.However, it is important to note that the size of the microduct bundle normally remains constant from the beginning of the layout to the end, so that, even if segregations have been previously made, the number of microducts available in the bundle remains the same. The only thing that happens is that the microducts that have already been segregated cease to have continuity until the distribution point (they are left "dead", as they are usually called in the jargon). This is usual in the state of the art, as can be seen in Figure 5A, where the segregated conduits are seen and how they are left "dead" at one of their ends (51A, 52A, 53A) since they are interrupted at the segregation point (normally closing them with a plug as seen in the figure).In order to perform the calibration test more efficiently, it is advisable to use these "dead" (micro)ducts, not interrupting them but giving them continuity from the FTTF point to the end of the route. In this way, from the FTTF point there is individualized continuity to the distribution point (PD) in one direction, and also to the end of the line or end of the conduit pipe bundle (54) in the opposite direction (as can be seen in Figures 5B and 5C). If we join both ducts at the FTTF point, we will therefore have end-to-end continuity, between the distribution point (PD, 50), the start point of the pipe bundle (start of the pipe bundle), to the termination point of the line or pipe bundle (end of the pipe bundle, 55A). The beacon object of the invention allows such a union and also allows the passage of a calibrated mandrel system (ball chain), in order to perform the subsequent calibration test.

[0092] In other words, when a conduit is segregated from a bundle of conduits in the pipeline (to prepare a service connection near a home to subsequently be able to serve said home if required), said conduit is divided into two: a first conduit that runs from the distribution point to the point where the home will be connected to the network when required (FTTF or HP+ point), and a second conduit (which is no longer useful from the point of view of the fiber optic service) that runs from the segregation point to the end point of the bundle of conduits (end of layout or line point). In one embodiment of the present invention, the electromagnetic beacon is connected, at the FTTF point, to the ends of said first and second conduits (for this purpose, the second conduit, which normally only reaches the segregation point, must continue to the FTTF point).

[0093] The use of the beacon object of the invention for pressure testing, continuity verification and calibration will now be explained with a graphic example.

[0094] Figures 5B and 5C schematically show a section of a distribution network that starts at the distribution point and runs along the planned route, serving different properties or buildings (this figure shows a network diagram in which only three electromagnetic beacons are used to mark the FTTF points of three different properties; this is only a simplification, but in general the number of points marked with beacons in a network is much higher). As can be seen, in front of each property or building, an individual microduct is segregated, and at the end of each segregated microduct, a beacon is connected to mark the segregation point, in accordance with an embodiment of the present invention. The network, except for the distribution point, is completely buried. The scenario shown in Figures 5 is only a simple, non-limiting example to illustrate the present invention.Of course, the present invention can be used with a greater or lesser number of beacons and each with other resonant frequencies.

[0095] The beacon marks the end of the service microduct for each property or building, through which each home will be connected to the fiber optic network when service is to be provided to that home. To do this, each service microduct (in these figures, the first three microducts in the microduct bundle) will be interrupted by connecting one end to the electromagnetic beacon that will mark that point. However, as indicated, the other end of the segregated microduct (51B, 52B, and 52B in Figure 5B and 51C, 52C, and 53C in Figure 5C) will not be left without continuity, but will be joined at the beacon (through the internal conduit). In this way, from the FTTF point, there is individualized continuity to the distribution point (DP) in one direction, and also to the end of the line or end of the conduit bundle (54) in the opposite direction.

[0096] In the case shown in Figures 5B and 5C, the beacons' resting frequency (without introducing pressure into the microduct) is the same, fi = 101.4 kHz; therefore, at all FTTF points, the beacon could be located at a frequency fi = 101.4 kHz. This makes it possible to locate the beacon and determine where a hole should be drilled to recover the buried microduct. However, its resting function cannot guarantee that the microduct has been correctly segregated from the main bundle. In this specific example in Figures 5B and 5C, the beacons' second resonant frequency is f2 = 92 kHz.

[0097] To verify whether the segregations have been performed correctly, pressure must be applied to the microduct to be tested at the end (pressure and continuity test). Figure 5B shows how the pressure and continuity test is performed. In the specific case of this figure, pressure (pressurized air) will be applied to the ends of the microducts located at the distribution point. By applying pressure, for example, to the first microduct (the one serving the first house on the left), the frequency at which the beacon can be detected at the first house in the diagram changes from 101.4 kHz to 92 kHz. Since the beacon's resonant frequency has changed, this means that continuity is correct and that the pressure test is also successful. For the test to work correctly, the end of the microduct to be tested (55B) must be properly sealed with a plug.

[0098] This same thing can be done in each microduct in the pipeline, applying pressure from microduct to microduct at one end and measuring the resonant frequency of the beacon at the other end, ensuring that the segregation has been carried out correctly and also that the network has been installed without damage (since for the frequency to change, a pressure threshold (Ui) must be exceeded that would guarantee this). If in any of the beacons, when applying pressure at the other end of the microduct to which the beacon is connected, the beacon does not change resonant frequency, the test will not have passed and, therefore, there has been some error in the channeling of that microduct.

[0099] In the case of performing the calibration test (Figure 5C), a calibration piece (usually metal) will be inserted through one end of the microduct to be tested. This piece (usually called a mandrel or mandling system or mechanism) has a predetermined caliber, such that if it passes through the conduit from one end to the other, it means that the conduit has a sufficient internal diameter throughout its entire length to pass the desired fiber optic cable without problem. This mandrel, in one embodiment, is a ball chain, for example.

[0100] Once the part is inserted, compressed air is then applied so that the ball chain circulates through the microduct to be tested, passing through the bypass beacon located in the FTTF and reaching the end of the line (55°C) if the layout is not damaged. This can be done individually for all microducts that exit the same PD and arrive at the same end point of the layout or channel. That is, it can be done for all microducts in a microduct bundle, without having to have personalized access to both ends of each microduct (at the FTTF or HP+ point), since, with the proposed beacon, all microducts in the bundle begin and end in the same place (instead of leaving them interrupted, as in the state of the art).

[0101] This calibration test can be repeated for each segregated duct in the pipeline (or for a specific bundle of ducts in the pipeline) to verify that all ducts are correctly installed.

[0102] Next, a beacon is described according to an embodiment of said invention that is presented as a non-limiting example thereof.

[0103] In one embodiment, the electromagnetic beacon of the present invention may be composed of different elements to achieve the following desired functionalities: on the one hand, to have a resonant circuit (for example, an LC circuit) inside the beacon, which allows the resonant frequency of the resonant circuit to change from a certain pressure and, on the other hand, to have the sealed connection of the beacon to two conduits (microducts) of the pipeline network (joining them internally by an internal conduit); or more specifically, to two ends of conduits of the pipeline network. Normally, as explained above, one conduit of the pipeline network will be cut, giving rise to two (sub)ducts, the ends of which will be connected to the beacon.

[0104] Figure 6 shows an exploded view of the proposed beacon where its main elements are presented, according to an embodiment of the invention.

[0105] In this embodiment, the beacon (60) would be formed by the following main parts (this is only a non-limiting example and in other embodiments there may be other different elements and another number of elements):

[0106] - A piece (61) that allows the connection with two microducts, with an internal bypass (internal conduit) that communicates the two ends of connected microducts. This piece (61) for the coupling of two conduits or pipes of the pipeline (microducts), must also have a small air passage channel or pressure intake (for example, a hole in the internal conduit) that allows the passage of air to a pressure measurement chamber located below. This channel would be rear, in the sense that it would normally be on the side opposite to the one designed to connect with the microducts (which is considered the front side of the beacon).

[0107] This piece, on the one hand, must be suitable for coupling to (standard) connectors that connect it to the microducts. In one embodiment, as shown in Figure 6, this piece will have two openings (611, 612) on one side with a shape (which could be cylindrical) and with an appropriate outer diameter so that each one can be connected to a microduct of standard dimensions. These openings have an elongated / longitudinal shape (in one embodiment, as shown in Figure 6, they will be cylindrical); at one end they will be connected to one end of the microduct and, at the other, to the internal conduit (bypass) that joins the two openings within the beacon. In one embodiment, the connection between the beacon (specifically, the two openings of this piece of the beacon) and each microduct will be through a standard connector for connecting conduits in a pipeline (and more specifically microducts). Figure 10 shows one of these connectors.

[0108] On the other side (opposite where it connects to the microducts), this piece will be adapted to the cavity or chamber where the pressure measurement will be performed. This piece may include a retention system with the next piece; this could be a screw fitting, bayonet fitting, or any other system that can withstand sufficient pressures (for example, pressures up to 16 bars).

[0109] - A rubber seal or membrane (62) that creates a tight seal against the part that connects to the microduct and also against the next part that will hold the rest of the beacon. The space created between the first part and the rubber membrane is a pressure chamber.

[0110] - A piece (63) designed so that on one side it is held by a thread or crimp system (or any other known joining system) against the first piece (61), and that in said union it exerts perimeter pressure with the elastic rubber membrane (stem or similar element) located between both pieces. Said union is watertight, supporting a pressure of, for example, up to 16 bars. Between the membrane and this piece (63) there is also a small cavity designed to allow the deformation of the membrane when the pressure in the pressure chamber increases. In this way, the pressure that has entered through one of the ends of one of the connected microducts and that reaches the beacon, deforms the membrane and this will activate the element of the resonant circuit activated by pressure, causing the change in frequency of the resonant circuit.In one embodiment (where the resonant circuit is of the type shown in Figure 4), the deformation of the membrane will actuate the button located just behind it, adding the capacitance C. ato the LC resonant circuit, so that it passes from one resonant frequency to another; in this embodiment (in which the resonant circuit has a pressure-activated switch / push button as shown in Figure 4), this second cavity is communicated with a space that may be an orifice, in which a switch / push button is positioned that is responsible for, when it receives sufficient pressure, modifying the resonant circuit so that it passes from h to 12. The push button is positioned so that its movable stem or push button is touching the rubber membrane. An increase in pressure in the pressure chamber will generate a deformation in the rubber membrane, actuating the push button and therefore modifying the resonant circuit. It can be said that this piece (63) therefore provides support to both the membrane and the pressure switch or, in general, to the pressure detector of the resonant circuit.

[0111] - This piece (63) is also designed to be fastened to a piece (64) or casing that would house the core of the resonant circuit (65) whose resonant frequency varies with the pressure (in the specific example in Figure 6, it is a two-frequency resonant circuit with a pressure switch). In one embodiment, this casing (64) will be cylindrical in shape and is designed to safely house the resonant circuit and protect it from the environment in which it will be installed (normally buried), conveniently covering it. That is, in this embodiment (which is a non-limiting example) there would be 5 pieces, 4 pieces (61-64), normally plastic (although they could be made of another material) plus the resonant circuit as a whole.

[0112] - Resonant circuit: As indicated, the resonant circuit could be of any type in which the resonant frequency varies when the pressure exceeds a certain threshold. In one embodiment (shown in Figure 7 and based on the resonance scheme shown in Figure 4) it can be composed of: a coil (71) with inductance L for example, formed by a ferrocylinder and a copper coil surrounding it, the ends of the beacon connected to a capacitor (72) with capacity Ci and in parallel another capacitor (73) with capacity C a in series with a pressure-activated pushbutton / switch (74); connected in parallel to the capacitor with capacity Ci and the coil L (in one embodiment the coil could be formed by a ferrite cylinder and a wire of conductive material, copper or similar). When the pressure rises above a certain threshold, the switch closes, the circuit capacity changes (from Ci to Ci+C a) and therefore the resonant frequency varies.

[0113] Figure 8 shows a sectional view of the beacon, according to an embodiment of the invention, with all its parts assembled. The internal bypass (81) for the passage of the calibration balls and the channel for the pressure intake (82), or in other words for the passage of pressurized air that enters through one of the connected microducts, can be seen. This channel is small enough so that it does not pose an obstacle to the passage of a chain of mandrel balls used in the calibration test. In the figure, it can be seen how the pressure chamber (83), which receives the pressure from the channel, is next to the membrane (84) so ​​that, once pressure is introduced at one end of the microduct, the pressure will reach the membrane through the channel, which will be deformed, pressing the button and changing the frequency of the resonant circuit.Thus, using a resonant circuit frequency detector, it is possible to detect from the surface (without the need to make any holes) whether the continuity and pressure tests are correct (whether the resonant frequency has changed).

[0114] In the following section view (figure 9) you can see the internal bypass for the passage of the calibration mandrel (91) and the channel (92) of the pressure passage to the pressure chamber (93). You can clearly see that the dimension of this channel (or hole) in an axis has very small dimensions with respect to the circular section of the internal bypass (91) so it will allow the passage of the calibration mandrel (balls) without problems.

[0115] In summary, this text describes an electromagnetic marker device (beacon) designed (with two openings) to be connected (in a hermetic manner) to two different conduits (microducts). These openings (also called inlets) are connected by an internal conduit (bypass) within the beacon that allows a mandrel mechanism (ball chain) to pass from one opening to the other, also allowing said bypass to pass air from the conduits into the interior of the beacon. This beacon incorporates a resonant circuit (e.g., a coil and capacitor LC circuit) capable of resonating at two different frequencies depending on the pressure inside one of the microducts to which the device is connected.

[0116] This device not only allows the location of the tips of the (micro)ducts to which it is connected, but also allows (by carrying out the corresponding procedures) to verify the correct installation of the duct network.

[0117] Specifically, this device allows the continuity of a pipeline's (micro)ducts to be verified without having to have one end accessible (i.e., with one end completely buried). It also allows for a pressure test, verifying that the beacon changes frequency at each point in the network where it is buried (which indicates that sufficient pressure is reaching that point and, therefore, that there have been no leaks or significant damage to the pipeline).

[0118] Furthermore, the device allows a (micro)duct channel calibration test to be carried out, without the need to have the point to be tested accessible (the FTTF or HP+ point, where the beacon is buried) and with a single accessible point at the end of the route or common line for both pipes (ducts).

[0119] Although in many of the embodiments set forth in this text, the present invention is applied in microducts of a fiber optic conduit, this is only a non-limiting example, since the present invention can be used in any type of ducts / pipes / conduits without being limited by their dimensions or their use (it could be for gas, water...).

[0120] In this text, the word "comprise" and its variants (such as "comprising," etc.) should not be construed as exclusive, that is, they do not exclude the possibility that the description includes other elements, steps, etc. Likewise, in the claims, the expression "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. No reference symbol in the claims should be construed as limiting the scope.

[0121] The specific design of each element and component shown in the figures is for illustrative and exemplary purposes only; in no case is the design of each component intended to be limited to that shown in said figures.

[0122] The aspects defined in this detailed description are provided to aid in a thorough understanding of the invention. Accordingly, those skilled in the art will recognize that variations, changes, and modifications may be made to the embodiments described herein without departing from the scope of the invention. Furthermore, the description of well-known features and elements is omitted for the sake of clarity and conciseness.

[0123] Having sufficiently described the nature of the invention, as well as the manner of its implementation in practice, it must be noted that its different parts may be manufactured in a variety of materials, sizes and shapes, and that variations that practice advises may also be introduced into its constitution or procedure, as long as they do not alter the fundamental principle of the present invention.

Claims

CLAIMS 1. Electromagnetic device (60) for verifying continuity, pressure and calibration in conduits of a pipeline, comprising: - A resonant circuit (65) whose resonant frequency varies from a first frequency, fi, to a second frequency, Í2, when the pressure in a pressure-sensitive element of the resonant circuit is greater than a first predetermined pressure threshold; - Two openings (611, 612) at one end of the electromagnetic device (60), where each opening is designed to connect to one end of a conduit of the pipeline; - An internal conduit (81) connecting, within the beacon, the two openings (611, 612), where said internal conduit (81) has a hole; - A housing (64) that houses and protects the resonant circuit (65).

2. Electromagnetic device (60) according to claim 1, wherein the resonant circuit (65) includes two capacitors in parallel (72, 73), connected by one of its ends to a pressure-activated switch (74), which closes when the pressure received by said switch is greater than the first predetermined pressure threshold or where the resonant circuit (65) includes a capacitor whose capacity changes value when the pressure it receives is greater than the first predetermined pressure threshold or where the resonant circuit (65) includes a coil whose inductance changes value when the pressure it receives is greater than the first predetermined pressure threshold.

3. Electromagnetic device (60) according to any of the preceding claims, wherein when the beacon is connected to two ends of pipeline conduits through their openings (611, 612), the pressure in the pressure-sensitive resonant circuit element depends on the pressure received by the end of one of the conduits to which the electromagnetic device is connected.

4. Electromagnetic device (60) according to any of the preceding claims, wherein the device (60) comprises a first part (61) where the two openings (611, 612) and the internal conduit (81) are located, where the hole of the internal conduit (81) allows the passage of air through a channel (82), to a pressure measuring chamber located between this first part (61) and a membrane (62) and where this membrane deforms when the pressure in the chamber increases and transmits said pressure increase to the pressure-sensitive resonant circuit element.

5. Electromagnetic device (60) according to claim 4, wherein the device comprises a second part (63) attached to the first part (61) by means of a retention system, where the membrane (62) is located between both parts (61, 63) and where this second part (63) is attached to the housing (64).

6. Electromagnetic device (60) according to any of claims 4 to 5, wherein the connection between the first (61) and the second piece (63) is made by means of a retention system that can withstand pressures of up to 16 bars.

7. Electromagnetic device (60) according to any of the preceding claims, wherein each of the openings (611, 612) has a cylindrical shape and an external diameter suitable for connecting to the conduits of the pipeline.

8. Electromagnetic device (60) according to any of the preceding claims, wherein the conduit is a conduit of a fiber optic network and the conduits to which the device is connected are microducts.

9. Method for performing calibration tests on conduits of a pipeline, using the electromagnetic device (60) described in any of the preceding claims 1-8, wherein the method comprises: a) Connecting in a sealed manner, one of the openings (611) of the electromagnetic device (60) to one end of a first conduit of the pipeline and another of the openings (612) to one end of a second conduit of the pipeline; b) Introduce a piece with a predetermined caliber through the other end, not connected to the beacon (60), of the first duct together with pressurized air; c) If the piece exits through the end of the second duct not connected to the beacon (60), then determine that the result of the calibration test performed is positive.

10. Method for performing continuity verification tests and pressure tests on conduits of a pipeline, using the electromagnetic device (60) described in any of the preceding claims 1-8, wherein the method comprises: a) Tightly connecting one of the openings (611) of the electromagnetic device (60) to one end of a first conduit of the pipeline and another of the openings (612) to one end of a second conduit of the pipeline; b) Introducing pressurized air through the other end, not connected to the beacon (60), of the first conduit; c) Detecting the resonant frequency of the electromagnetic device (60) and, if the resonant frequency has changed with respect to the resonant frequency of the device in the absence of pressurized air, then determining that the result of the test performed is positive.

11. Method according to claim 10, wherein the pressure in the pressure-sensitive resonant circuit element depends on the pressure at the end of the first conduit to which the electromagnetic device (60) is connected and wherein, in order to perform the pressure test at the same time as the continuity check test, the first predetermined pressure threshold is sufficiently high such that the pressure in the element reaches that threshold when there are no leaks in the first conduit and wherein, if in step c) the resonant frequency has changed with respect to the resonant frequency of the device in the absence of pressurized air, then it is determined that not only the result of the continuity check test but also the result of the pressure test is positive.

12. Method according to any of claims 10-11, wherein if in step c) the resonant frequency does not change, then the pressure at the end is measured of the duct through which pressurized air is introduced to determine whether the pressure test or the continuity verification test has failed.

13. Method according to any of the preceding claims 9-12, wherein the conduit is a conduit of a fiber optic network and the conduits to which the device is connected are microducts.

14. Method according to claims 9-13, wherein step c) is performed, with the electromagnetic device (60) being buried.

15. Method according to any of claims 9-14, wherein the conduit is a conduit of a fiber optic network and where the first conduit is a conduit that goes from the distribution point of the fiber optic network to the connection point to a home, FTTF or HP+ point, and the second conduit is a conduit that goes from said connection point to the end of the bundle of conduits or end of line (or layout).

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