Electromagnetic device and method for verifying continuity and pressure in conduits

Abstract

The present invention relates to an electromagnetic device (70) for verifying continuity and pressure in conduits of a channel, the device comprising a resonant circuit (75), the resonance frequency of which varies when the pressure is higher than a first predetermined pressure threshold, a first part (71) that allows the passage of air to a pressure measuring chamber located between this first part and a membrane (72) that is deformed when the pressure increases in the chamber and transmits said increase to a pressure-sensitive element that forms part of the resonant circuit. The device is connected to a conduit of a fibre network channel and has two different resonance frequencies depending on the pressure inside the conduit. The associated method allows verification tests to be performed in a channel of conduits for an optical fibre network, in a quick, accurate, repetitive and auditable manner.

Description

[0001] ELECTROMAGNETIC DEVICE AND METHOD FOR VERIFYING CONDUCT CONTINUITY AND PRESSURE

[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 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 for deployments to be carried out without installing manholes or intermediate registers, 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.

[0008] Therefore, marking the pipeline and recording its route is especially important, as it is necessary to know precisely where the pipeline runs in case a repair is necessary.

[0009] 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.).

[0010] 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).

[0011] It is 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 normally runs from a head office (or point of presence, PDP) to a distribution point (DP). A distribution point can serve a certain number of properties (N) and therefore typically concentrates a number of connections on the distribution side and reduces them to a single cable or two toward 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 separation 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.

[0012] In fiber optic networks, the concept of passed-through 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 could potentially be connected to the fiber optic network in an area if their owners were to subscribe to the service because the fiber optic network is deployed in that area. It is quite common, during the deployment phase (when we talk about passed-through homes), for the service section of the service network (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 home is not simply passed through a provider's network, but rather a home that has subscribed to that provider's service and is connected to its network).In certain cases, a partial service connection may be deployed to reduce 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 Past Plus (HP+), or 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) extends to the property's fence. Figure 1 shows where the FTTF point would be located in the basic network diagram shown.

[0013] All network sections are inventoried and are eligible for marking with electromagnetic beacons at the discretion of each operator. However, the 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).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.

[0014] 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, it signals the end of a service entrance microduct through which the home will be connected to the fiber optic network when service is required. To do this, the service entrance microduct is connected at one end via a connector to the corresponding microduct in the distribution network, and at the other end, it is connected to the electromagnetic beacon (via 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.

[0015] The FTTF point is just one example of a “singular” point that is signaled with a beacon in a fiber optic network, but there may be many other types of points in the network, which for one reason or another, should be located and, therefore, may have to be signaled with a beacon in a fiber optic network.

[0016] There are different types of location beacons for these functions. There are many types of beacons, but here are just a few of the most common types found on the market:

[0017] • 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 perpendicular to the surface, and the beacon includes the necessary means for this: self-leveling system, fluids, etc.).

[0018] • Flat plate-type beacons. This type of beacon can be detected at depths of between 2 and 3 meters, provided it is installed in the correct position.

[0019] • 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).

[0020] All of these locator beacons typically incorporate a resonant circuit (completely passive, usually a coil with a ferrite core and a capacitor) that can be detected when excited by an electromagnetic signal at the appropriate frequency (usually depending on the type of buried service, a different frequency is 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).

[0021] Depending on the application and the circumstances of the associated project, 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 line.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.

[0022] 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.

[0023] 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.

[0024] 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 guarantee the quality of the conduit. In the case of a conduit installed with microducts, three main types of tests are typically performed: • 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. Microducts of different colors are commonly used, and during deployment, there is always a risk of confusing colors when installing the different branches, causing the actual configuration to not correspond to what was planned (i.e., the actual layout or route of a microduct may not be correct), and therefore, it must be tested.

[0025] • 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.

[0026] • 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 may be damaged by impacts or crushing, typically 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.

[0027] 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, it was necessary until now to have both ends of the duct 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); thus verifying, from the distribution point to the customer, that everything is correct.And in the calibration test, a gauge (e.g., a mandrel type) is inserted into one end of the (micro)duct, and the other end must be open to remove it and verify that everything is correct (the internal diameter of the microduct is undamaged); therefore, for the calibration test, in existing solutions, both ends of the (micro)duct must also be accessible.

[0028] 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.

[0029] 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 (which has been essential until now 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. The possibility of keeping the holes open continuously or indefinitely is practically impossible for reasons of safety and public administration permits. The possibility of opening the holes every time the tests are required may also be unfeasible due to permit issues and very costly in terms of both time and money, due to the amount of work required.

[0030] 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.

[0031] Therefore, there is a need for a technical solution that minimizes the time and resource costs of these tests, yet still performs them accurately, as they are essential for the pipeline's proper functioning.

[0032] Summary of the invention

[0033] The present invention addresses the aforementioned problems by means of a novel electromagnetic beacon that not only identifies the location of a fiber optic conduit duct to which it is connected, but also allows for continuity and pressure verification tests to be performed on fiber optic conduit ducts in a manner improved compared to existing procedures. Typically, such fiber optic conduit ducts will be microducts.

[0034] Thus, the present invention provides a new electromagnetic device (also called a beacon due to its signaling function) and a measurement method that allow, through the use of this device, continuity and pressure verification tests to be carried out on a conduit pipeline (microducts), in a fast, precise, repetitive and auditable manner.

[0035] The present invention also saves resources and time since, among other things, there is no need to have access to both ends of the pipeline and, therefore, there is no need to make holes in most cases to perform these tests (as will be explained later, to perform the tests it is only necessary to have access to one of the ends of the pipeline, which is quite common from the distribution point).

[0036] Specifically, in a first aspect of this invention, an electromagnetic device is presented for verifying continuity and pressure in conduits of a pipeline, where the electromagnetic device is designed to be connected at one of its ends to a conduit of the pipeline (for example, the device has the appropriate physical form at one of its ends to be connected to a conduit of the pipeline through a standard connector or has appropriate means to be connected to the conduit of the pipeline), comprising:

[0037] - 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;

[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 electromagnetic device is connected to the conduit, the pressure across the pressure-sensitive resonant circuit element is dependent upon the pressure received (e.g., pressurized air is received) by the end of the conduit 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 the pipeline duct) only reaches or exceeds that threshold when there are no leaks in the pipeline layout for that conduit.

[0041] In one embodiment, the device comprises a first part that allows the device to be connected to the conduit, where this first part allows the passage of air to a pressure measuring chamber located between this first part and a membrane and where this membrane deforms when the pressure in the chamber increases and transmits said pressure increase to the element of the pressure-sensitive resonant circuit (in this way the pressurized air that has been introduced through one of the ends of the conduit and that reaches the beacon is transmitted to the resonant circuit so that it passes from one frequency to another).

[0042] The device may 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 may be achieved by 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, may be joined, for example, by a retention system, such as a screw connection or a bayonet connection.

[0043] In one embodiment, one of the ends of the device (the one that connects to the conduit) has a cylindrical shape and an external diameter suitable for connecting to the conduit of the pipeline of standard dimensions (for example, through a standard conduit connector)

[0044] In one embodiment, the conduit is for a fiber optic network and the conduit to which the device connects is a microduct.

[0045] In a second aspect of this invention, a method is presented for performing continuity verification tests and pressure tests on conduits of a pipeline (for example, a pipeline of a fiber optic network), using the device described above, where the method comprises: a) Connecting the electromagnetic device to one end of a conduit of the pipeline, in a sealed manner; b) Introducing pressurized air through the other end of the conduit (the end not connected to the device, which may be located for example at a distribution point of the fiber optic network); c) Detecting the resonant frequency of the electromagnetic device; d) If the resonant frequency has changed with respect to the resonant frequency of the device in the absence of pressurized air (that is, it is not fi but Í2), then determining that the result of the test performed (continuity and / or pressure verification) is positive.

[0046] In one embodiment, the conduit to which the device connects is a microduct.

[0047] In one embodiment, step c) is performed with the end of the conduit connected to the electromagnetic device and the electromagnetic device buried.

[0048] In one embodiment, the pressure across the pressure-sensitive resonant circuit element depends on the pressure received by the end of the 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 conduit through which the air is introduced). This threshold may be, for example, 8 bars. If, in step d), 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.

[0049] In one embodiment, prior to step a), a conduit is segregated from a bundle of conduits in the pipeline, the conduit is cut, and the electromagnetic device is connected to one (cut) end of the segregated conduit, where the end of the conduit where the device is connected is the end of the conduit through which a home will be connected to the fiber optic network, when said home is to be serviced. The method can be repeated for each segregated conduit in the pipeline, connecting an electromagnetic device to each of the segregated conduits.

[0050] In one embodiment, if the resonant frequency does not change in step d), then the pressure at the end of the conduit through which pressurized air is introduced is measured to determine whether the pressure test or the continuity verification test has failed. 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.

[0051] Brief description of the figures

[0052] 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.

[0053] FIGURE 1.- Shows schematically the different sections into which a FTTH fiber optic access network can be divided.

[0054] FIGURE 2.- Shows schematically a scenario where an FTTF point is marked with an electromagnetic beacon.

[0055] FIGURE 3.- Shows schematically the connection of the beacon proposed in the present invention to a microduct, 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 5.- 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.

[0058] FIGURE 6.- Shows the external shape of a beacon, according to an embodiment of the invention.

[0059] FIGURE 7.- Shows an exploded view of the proposed beacon, according to an embodiment of the invention. FIGURE 8.- Shows a view of the resonant circuit of the proposed beacon, according to an embodiment of the invention.

[0060] FIGURE 9.- Shows a sectional view of the beacon, according to an embodiment of the invention.

[0061] FIGURE 10.- Shows a view of a standard connector for connecting microducts.

[0062] Detailed description of the invention

[0063] 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.

[0064] The electromagnetic device (beacon) proposed in the present invention is resonant at different frequencies and is connected to a microduct (or more generally to a conduit) of a fiber optic conduit, so as to allow its location, in addition to allowing the verification and certification of the microduct conduits by continuity and pressure.

[0065] The beacon is designed to be able to be connected (directly in one embodiment) to a conduit, typically a micro-duct (better known as a microduct), in a robust and completely watertight manner (there is no loss of pressure or airflow due to the connection of the beacon to the duct). That is, the beacon must be able to connect to the microduct (in other words, be connectable to the microduct). To this end, in one embodiment, it will itself have the necessary means to connect to the microduct. However, in a preferred embodiment, the beacon will have the appropriate physical shape to be able to connect to the (micro)duct and, specifically, may have at one of its ends the appropriate shape to allow (quick) connection to the microduct through the use of standard microduct connectors (as if it were a connection that provides continuity between two microducts).That is, in one embodiment, the beacon at one of its ends must have the physical shape of a duct, of the same or similar diameter as the duct to which it is to be connected.

[0066] Figure 3 shows schematically said connection between a microduct (31, on the left), a connector (32, in the center) and the marker beacon object of this invention (33, on the right).

[0067] 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 f 1 , and when the conduit to which it is connected is subjected to a pressure greater than a threshold (U1), it resonates at a frequency f2. The way in which the frequency change is carried out may vary depending on the implementation.

[0068] 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, and the inductance L in henries):

[0069] 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).

[0070] C 2 - C 1 + CThis change in capacitor capacitance can be achieved in numerous ways. In one embodiment, for example, a push button / 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 Ci and C 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 (Ci) 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 (Ci + 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.

[0071] Thus, for example, by conveniently choosing the circuit parameters and specifically, for example, the capacities of the capacitors to be used, the circuit can be made to resonate at frequencies that are commonly used in commercial beacons to signal different services (as shown in the following table).

[0072] Thus, the first frequency h could be the frequency used to mark buried telephone lines 101.4 kHz and the second frequency I2 the one used to mark buried fiber optic lines 92 kHz. This is just a non-limiting example and other frequencies could be used depending on the services to be marked, the chosen criteria... and, in general, by appropriately choosing the circuit parameters, it can resonate at the desired fi and I2 frequencies according to the application where the beacon is going to be used.

[0073] The pressure-activated switch / pushbutton 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).

[0074] There is no need for a pressure-activated switch / button, as a capacitor whose capacity changes with pressure would also be suitable.

[0075] 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).

[0076] As explained below, the placement of a beacon like the one described above (resonant at different frequencies depending on the pressure) allows for pipeline continuity and pressure testing in a novel and highly operationally and economically convenient manner (because it allows continuity and pressure verification tests to be performed without the need to have both ends open to perform the tests correctly). Performing pressure and continuity verification tests with 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.

[0077] 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.

[0078] If testing is 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 underground). Leaving the holes open indefinitely throughout the entire deployment period is practically unfeasible.

[0079] However, with the beacon described in this invention, which changes frequency with pressure, it is possible to perform both tests at any time, without having to slow down the pace of the work and without having to open holes afterwards to perform the tests.

[0080] To perform the continuity verification test, with one end of the pipeline available (usually 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 other end of the microduct), since, at that location and when pressure is introduced into the circuit, the resonant frequency of the beacon will change temporarily (until the pressure is removed).

[0081] 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).

[0082] 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.

[0083] 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.

[0084] If this pressure threshold is low enough, 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).

[0085] 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, this indicates a successful continuity test. However, it will only indicate a successful pressure test if the beacon's pressure threshold is high enough. 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. However, it will not be possible to determine which of the two causes (lack of continuity or a leak 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 a continuity or pressure fault.However, in case of failure (the resonant frequency does not change) it would be possible to check if the pressure test is correct, since from the end from which the pressure is introduced the pressure could be checked (with a standard pressure gauge), and therefore determine the reason why the beacon is not activated (if the gauge indicates that the pressure is correct, then it would be a continuity fault).

[0086] The use and functionality of the beacon object of the invention will now be explained with an example.

[0087] Figure 5 shows a schematic representation of a distribution network section that starts at the distribution point and runs along the street, serving different properties or buildings. (This figure shows a network diagram in which only three electromagnetic beacons are used to signal the FTTF points of three different properties; this is merely a simplification, but in general, the number of points signaled 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 signal the segregation point. The network, except for the distribution point, is completely buried.

[0088] Or in other words, the beacon marks the end of the service microduct for each home, through which each home will be connected to the fiber optic network when service is desired for that home. To do this, each service microduct (in the case of Figure 5, the first three microducts in the bundle of microducts) will be interrupted by connecting one end to an electromagnetic beacon that will mark that point. In the case shown in Figure 5, the beacon's resting frequency (without putting pressure on the microduct), which is the one shown in Figure 5, is the same and is fi = 101.4 kHz; therefore, at all microduct ends, 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 dug to recover the buried microduct. However, its function at rest cannot guarantee that the segregation of the microduct from the main bundle has been done correctly.In this specific example in Figure 5, the other resonant frequency of the beacons is f2=92 kHz.

[0089] The scenario shown in Figure 5 is just 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, each with different resonant frequencies.

[0090] To verify whether the segregations have been performed correctly, it is necessary to apply pressure to the microduct being tested, at the end of the microduct. In the case of Figure 5, pressure will be applied to the ends of the microducts located at the distribution point.

[0091] Figure 5 shows how pressure (pressurized air) is introduced into the first microduct in the microduct bundle. 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 has changed its resonant frequency, this means that the continuity is correct and the pressure test is also successful.

[0092] Let's imagine that when pressure is applied to the second microduct (the one serving the second house), the frequency at which the beacon can be detected in the second house in the diagram also changes from 101.4 kHz to 92 kHz. So, in this case, the continuity and pressure test are correct. The same can happen in the third microduct (the one serving the third house).

[0093] This same approach can be followed for each test by applying pressure from one end of the microduct to the other and measuring the resonant frequency of the beacon at the other end, ensuring that the segregation has been carried out correctly and that the network has been installed without damage (since, for the frequency to change, a pressure threshold must be exceeded to guarantee this). If, when applying pressure to the other end of the microduct to which the beacon is connected, the beacon does not change its resonant frequency, the test will not have passed and, therefore, there has been an error in the routing of that microduct.

[0094] Next, a beacon is described according to an embodiment of said invention that is presented as a non-limiting example thereof.

[0095] 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 change of resonant frequency of the resonant circuit from a certain pressure and, on the other hand, to have the sealed connection of the beacon to a conduit (microduct) of the pipeline network.

[0096] In Figure 6, the external appearance of a pointed beacon is shown, according to an embodiment of the present invention.

[0097] Figure 7 shows an exploded view of the proposed beacon where its main elements are presented, according to an embodiment of the invention.

[0098] In this embodiment, the beacon (70) 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):

[0099] - A part (71) that allows connection to a microduct and that allows the passage of air to a pressure measuring chamber located below. This part, on the one hand, must be suitable for coupling to a (standard) connector that connects it to the microduct. In one embodiment, this part will have a shape that could be cylindrical, on the one hand, with an external diameter appropriate to be able to connect to a microduct of standard dimensions. In one embodiment, the connection between the beacon (specifically this part of the beacon) and the microduct will be through a standard connector for connecting ducts in a pipeline (and more specifically microducts). Figure 10 shows one of these connectors.

[0100] On the other hand, this part can be adapted to the cavity or chamber in which the pressure measurement will be performed. This part must include a retention system with the next part; this could be a screw connection, bayonet fitting, or any other system that can withstand sufficient pressures (for example, pressures up to 16 bars).

[0101] - A flat gasket or membrane (72), which can be made of rubber or other elastic material, which creates a tight seal against the piece that connects to the microduct and also against the next piece that will hold the rest of the beacon. The space generated between the first piece and the rubber membrane is a pressure chamber.

[0102] - A piece (73) 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 (71), and that in said union it exerts pressure perpendicular to the elastic rubber membrane located between both pieces. Said union is watertight, supporting a pressure of, for example, up to 16 bars. Between the membrane and this piece (73) 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 the microduct and that reaches the beacon, deforms the membrane and this will activate the element of the pressure-activated resonant circuit, causing the change in frequency of the resonant circuit. In one embodiment (in which 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 capacity 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 phi to Í2. 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 (73) therefore provides support to both the membrane and the pressure switch or, in general, to the pressure detector of the resonant circuit.

[0103] - This piece (73) is also designed to be fastened to a piece (74) or casing that would house the core of the resonant circuit (75) whose resonant frequency varies with the pressure (in the specific example in Figure 7, it is a two-frequency resonant circuit with a pressure switch). This casing (74) 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 (71-74), normally plastic (although they could be made of another material) plus the resonant circuit as a whole.

[0104] This is just a non-limiting example, and in other embodiments, the number of parts can be 4 or any other number (greater or less than 5). The important thing is the functionality provided by the device (changing its resonant frequency when the pressure it receives through the microduct to which it is connected exceeds a threshold, allowing it to connect to a network conduit), regardless of the number of parts.

[0105] - 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 8 and based on the resonance scheme shown in Figure 4) it can be composed of: a coil (81) with inductance L, the ends of the beacon connected to a capacitor (82) with capacity Ci in parallel, another capacitor (83) with capacity C ain sign with a push button / switch (84) activated by pressure, connected in parallel to the capacitor of capacity Ci and the coil L (in one embodiment the coil could be formed by a ferrule cylinder and a wire of conductive material, copper or similar, surrounding it in the form of a coil). When the pressure rises above a certain threshold (Ui), the switch closes, the circuit capacity changes (from Ci to Ci+C a) and therefore the resonant frequency varies. Figure 9 shows a sectional view of the beacon, according to an embodiment of the invention, with all its parts assembled. It can be seen how the pressure chamber (91) is next to the membrane (92) so that, once pressure is applied to one end of the microduct, the pressure will reach the membrane which will deform, pressing the button (93) and changing the frequency of the resonant circuit. Thus, by means of equipment that detects the frequency of the resonant circuit, it can be detected from the surface (without the need to make any holes) if the continuity and pressure tests are correct (if the resonant frequency has changed).

[0106] In summary, this text describes an electromagnetic marker device (beacon) designed to be connected (in a sealed manner) to a conduit or microduct, which incorporates a resonant circuit inside (for example a coil and capacitor LC circuit) capable of resonating at 2 different frequencies depending on the pressure inside the conduit or microduct to which the device is connected.

[0107] This device not only allows you to locate the microduct to which it is connected but also allows (by carrying out the corresponding procedure) to verify the correct continuity of the microducts in a pipeline, without needing to have one of the ends accessible (that is, with one end completely buried).

[0108] It also allows for pressure testing to verify the correct installation of a microduct network, ensuring 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).

[0109] Although in many of the embodiments set forth in this text, the present invention is applied to microducts of a fiber optic conduit, this is only a non-limiting example, since the present invention can be used in any type of conduit without being limited by their size or use. In this text, the word "comprise" and its variants (such as "comprising", etc.) should not be interpreted in an exclusive manner, that is, they do not exclude the possibility that what is described 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 interpreted as limiting the scope.

[0110] 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.

[0111] 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 can 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.

[0112] 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 (70) for verifying continuity and pressure in conduits of a pipeline, where the electromagnetic device (70) is designed to be connected at one of its ends to a conduit of the pipeline, comprising: - A resonant circuit (75) 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; - A housing (74) that houses and protects the resonant circuit (75).

2. Electromagnetic device (70) according to claim 1, wherein the resonant circuit includes two capacitors in parallel (82, 83), connected by one of their ends to a pressure-activated switch (84), 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 whose capacity changes value when the pressure it receives is greater than the first predetermined pressure threshold or where the resonant circuit includes a coil whose inductance changes value when the pressure it receives is greater than the first predetermined pressure threshold.

3. Electromagnetic device (70) according to any of the preceding claims, wherein when the electromagnetic device (70) is connected to the conduit, the pressure in the pressure-sensitive resonant circuit element depends on the pressure received by the end of the conduit to which the electromagnetic device (70) is connected.

4. Electromagnetic device (70) according to any of the preceding claims, the device (70) comprises a first part (71) that allows the device (70) to be connected to the duct, where this first part allows the passage of air to a pressure measuring chamber located between this first part and a membrane (72) and where this membrane deforms when the pressure increases. pressure in the chamber and transmits this pressure increase to the pressure-sensitive resonant circuit element.

5. Electromagnetic device (70) according to claim 4, wherein the device comprises a second part (73) attached to the first part (71) by means of a retention system, where the membrane (72) is located between both parts and where this second part (73) is attached to the housing (74).

6. Electromagnetic device (70) according to claim 5, wherein the connection between the first (71) and the second piece (73) is made by means of a retention system that can withstand pressures of up to 16 bars.

7. Electromagnetic device (70) according to any of the preceding claims, wherein one of the ends of the device (70) has a cylindrical shape and an external diameter suitable for connecting to the pipeline conduit.

8. Electromagnetic device (70) according to any of the preceding claims, wherein the conduit is for a fiber optic network and the conduit to which the device is connected is a microduct.

9. Method for performing continuity verification tests and pressure tests on conduits of a pipeline, using the electromagnetic device described in any of the preceding claims 1-8, wherein the method comprises: a) Connecting the electromagnetic device (70) to one end of a conduit of the pipeline, in a sealed manner; b) Introducing pressurized air through the other end of the conduit; c) Detecting the resonant frequency of the electromagnetic device; d) 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.

10. Method according to claim 9, wherein the conduit is a conduit of a fiber optic network and where the end of the conduit through which pressurized air is introduced is at a distribution point of the fiber optic network.

11. Method according to any of the preceding claims 9-10, wherein step c) is performed, the end of the conduit being connected to the electromagnetic device (70) and the electromagnetic device (70) being buried.

12. Method according to any one of preceding claims 9-11, wherein the pressure in the pressure-sensitive resonant circuit element depends on the pressure at the end of the conduit to which the electromagnetic device 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 pressure-sensitive element reaches that threshold when there are no leaks in the conduit, and wherein, if in step d) 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.

13. Method according to any of claims 9-12, wherein the conduit is a conduit of a fiber optic network and where prior to step a), a segregation of the conduit of a bundle of conduits of the conduit is carried out, and the electromagnetic device is connected at one end of the segregated conduit and where the end of the conduit where the device (70) is connected is the end of the conduit through which a home will be connected to the fiber optic network, when it is desired to provide service to said home.

14. Method according to any of claims 9-13, wherein the method is repeated for each conduit of the segregated pipeline, to which an electromagnetic device described in any of the preceding claims 1-8 has been connected.

15. Method according to any of claims 9-14, wherein if in step d) the resonant frequency does not change, then the pressure at the end of the conduit through which pressurized air is introduced to determine whether the pressure test or the continuity verification test has failed.

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