RU172554U1 - End Fiber Detector - Google Patents

Abstract

The technical solution relates to fiber optic technology, namely to the end of the fiber optic detectors. The terminal fiber optic detector (CFI) contains a housing with a working body that provides a change in the position of the optical fibers of the sensitive part of the CFI, a sensitive part that is installed in the frame of the CFI and connected to the transport part, which provides the connection of the CFI to the branched optical network and the transportation of laser pulses in the forward and reverse direction. The sensitive part is made of optical fibers and a splitter, the outputs of which are closed between themselves by an optical fiber and form a closed loop, to form a reflection signal, a change in the geometric position of the fibers in the sensitive part of the CFI in the elastic deformation range, due to a change in the position of the working body, are such that they lead to a change the possibility of forming and passing reflection signals. The technical result consists in providing the possibility of guaranteed receipt of clear information about the reflection signal, depending on the position of the working body of the CFI. 5 cp f-ly, 6 ill.

Description

Technical field

The proposed utility model relates to fiber optic technology, namely to end fiber optic detectors (hereinafter referred to as CFI), the principle of operation of which is based on the use of the properties of optical fiber to change the transmission capacity of probe laser radiation depending on the geometric shape of the optical fiber, which is changed by the CFI working body. Information on the positions of the working bodies of the CFI is collected using an information processing device, an OTDR, and a fiber-optic cable network branched on splitters. The range of the COI placement can reach 50,000 m or more, while ensuring the required value of the energy of the probe pulse allocated to the COI.

KOI can be used in burglar alarm systems, panic alarm buttons, the status of gate sensors and gates of perimeters of small and extended territories, the position of manhole covers for well spaces, as well as the condition of doors of structures and premises, the position sensors of gully gangways, signaling the state of walls on the presence of cracks, fractures and breaks, liquid level sensors, ultimate pressure sensors, etc. without the use of electrical energy at a distance of 100 to 50,000 meters, in t including the use of CFI in explosive atmospheres, in conditions of 100% humidity, increased gas contamination and dust, when working in water, including fecal effluents, in conditions of increased radiation, in conditions that exclude the possibility of using electrical devices, in conditions of high-power electromagnetic interference.

State of the art

The prior art design of devices using optical fiber to record the status of various systems (see, for example, RU 2467397, 11/20/2012).

The disadvantages of this design are the inability to collect information distributed over considerable distances about the state of the moving parts of structures on which fiber-optic sensors are installed, based on the principle of changing the reflection signal level (return) depending on the position of the sensor’s working body.

Utility Model Disclosure

The technical result, the achievement of which the proposed technical solution is aimed at, is that it is possible to guaranteedly obtain clear information about the reflection signal, depending on the position of the working body of the CFI.

This problem is solved by creating an end fiber optic detector (CFI), comprising a housing with a working body that provides a change in the position of the optical fibers of the sensitive part of the CFI, a sensitive part that is installed in the frame of the CFI and connected to the transport part, which provides the connection of the CFI to the branched optical network and transportation laser pulses in the forward and reverse directions, the sensitive part of the CFI is made of optical fibers and a splitter, the outputs of which are optically closed m fiber and form a closed loop to form a reflection signal change the geometrical position of the fiber in the sensitive part of the koi in the elastic deformation range due to changes in the position of working body such that lead to changes in the possibility of forming the reflection and transmission signals.

In one embodiment of the claimed solution, the sensitive part of the CFI is a closed loop in the form of rings with a bending radius in the elastic range of deformations, allowing free passage of the reflection signal of the probe pulse in one of the positions of the working body and the bending radius of the rings in the elastic range of deformations in the second position of the working body to the form in which the signal of the probe pulse is absorbed in parts in the optical fiber cladding of the sensitive part of the CFI in places with the smallest radii to the required direct minimum values of the reflection signal.

In another embodiment of the claimed solution, the sensitive part of the CFI is a closed loop in the form of optical fibers rolled into rings and installed in the frame of the CFI in such a way that in one of the positions of the working body, some rings are in a state that allows the free passage of the signal of the probe pulse, and others rings in a state in which the signal of the probe pulse is absorbed in parts in the optical fiber cladding of the sensitive part of the CFI in places with the smallest radii to the required minimum th reflection signal values, and in the second position the working member ring positions reversed, providing inverted state signal reflections.

In another embodiment of the claimed solution, the sensitive part of the CFI is a closed loop in the form of optical fibers, rolled into rings and installed in the frame of the CFI so that two groups of rings are fixed on one side on the fixed part of the body, and the second sides of the rings are connected to each other and with a freely hanging movable working body, while the planes of the groups of rings are located in mutually perpendicular planes, which enable automatic retention of the rings in elastic deformation in the meeting the effort without taking aside the position of the moving load, compressed to the extent of the average level of energy absorption of the probe pulse in each groups of rings, providing a dynamic change in the reflection signals depending on the magnitude of the acceleration transmitted to the casing.

In another embodiment of the claimed solution, the spatial shape of the optical fiber of the sensitive part of the CFI is changed through the grips located on opposite sides of the rings of the sensitive element, some of the grips are connected to the movable part of the working body of the CFI, others to the base of the CFI body.

In another of the variants of the claimed solution, the grips are made in the form of segments of heat-shrink tubes of different diameters inserted into each other, some are designed to hold optical fibers rolled into rings, an optical bay, others are used to capture the first ones and form a mounting hole for attaching an optical bays to the moving and motionless parts of the CFI.

Thus, the claimed technical solution with all its essential features makes it possible to guarantee the receipt of clear information about the reflection signal, depending on the position of the working body of the CFI.

Brief Description of the Drawings

In FIG. Figure 1 shows the position of the sensitive part of the sensor — the bending radius of the fiber is more than the minimum critical value, the probe pulse and the reflected signal move freely in the fiber core in both directions.

In FIG. Figure 2 shows the position of the sensitive part of the sensor — the fiber bending radius is less than the critical value at which the probe pulse, reaching the fiber bending point, penetrates the fiber sheath and is absorbed in it, as a result of which a reflection signal is not formed.

In FIG. 3 shows the sensitive part of the sensor, made in the form of an optical fiber bay with grips attached to the sensor housing and to the movable part of the working body.

In FIG. 4 shows the sensitive part of the sensor, made in the form of two bays of optical fiber with grips attached to the housing of the sensor and to the movable part of the working body.

In FIG. 5 shows an example of a sensor operation in which the sensor element is made in the form of two bays of optical fiber with two common grips at the edges.

In FIG. 6 shows a general view of the COI sensor.

Utility Model Implementation

Reflection signals are generated at the input of the premix device as a result of the passage of the probe pulse in the opposite direction through a branched optical network, on the branches of which there are KOI.

The required value of the branch power to the COI, as a rule, should be significantly less than the initial value of the power at the OTDR output and depends on the characteristics of the emitter, the sensitivity of the OTDR receiving device, and the distance of the COI from the measuring device, which allows you to place many branches to the COI on one transport cable.

The magnitude of the branch power for each CFI according to the principle of operation of the device can differ by several times without deteriorating the operation of the device, which allows the use of taps with a wide range of branching. The power of the returned signal at the input of the receiving device, as a rule, should not exceed the saturation limits for the used receiving device and should not be lower than the permissible level comparable to the noise level. Exceeding the power of the reflected signal of the saturation limits of the receiving device does not interfere with the operation of the device.

The main result of collecting information from the CFI is the ratio of the magnitude of the power of the returned signal in one of the positions of the sensor to the magnitude of the power of the returned signal in another position. The ratio of the magnitude of the power of the returned signal in different states of the CFI can reach tens or more times and is considered by the measurement system as a discrete signal - “there is a signal” or “there is no signal”.

This problem is solved, and the technical result is achieved due to the fact that the CFI contains a housing (1) with a lever mechanism (4) that provides the movement of optical fibers of the sensitive part of the CFI, a segment of the optical fiber transport cable for connecting to a branched optical network and transporting laser pulses in direct and the opposite direction and the sensitive part, changes in the position of which lead to a change in its bandwidth and reflectivity.

KOI are optical-mechanical constructions in which, due to a change in the position of the working body of the sensor, a change in the magnitude of the power of the returned signals occurs. Changing the position of the working body is made when exposed to the elements of the working body.

The ability of the sensor to change the magnitude of the return pulse is made by changing the value of the bending radius and orientation of the optical fiber of the sensitive part of the sensor less than the value at which the integrity and elastic properties of the optical fiber are preserved, and the optical beam of the probe pulse penetrates the fiber sheath and is absorbed in the bend (see Fig. 1, 2).

The construction of a multi-point optical scheme for returning signals from sensors makes it possible to ensure the most efficient with low energy loss signals return to the receiving device, providing the maximum number of sensors on one line of the device.

When constructing the system, the duration of the probe pulse, the linear dimensions of the sensitive elements and the transport cable should be taken into account in order to prevent competition (overlapping) of the returned signals in time. Competition of the return signals is regulated by correcting coils consisting of the same type of optical fiber of the required length.

Work CFI using reflectometry method of measurement.

The basis of the device is the principle:

- receiving a reflection signal from the end of the line to the sensor (s) of sufficient power to confidently identify its location and magnitude of reflection;

- the ability to change the magnitude of the power of the reflection signal by changing the geometric dimensions of the optical fiber:

- the ratio of the power of the reflection signal in the state of maximum throughput of the sensor and the line to the value of the power of the reflection signal in the state of minimum throughput of the sensor and the line should provide an unambiguous determination of the state of the sensor for any indicated values of the interference factors affecting the line and the sensor (temperature, pressure, humidity, gas contamination, immersion in water, etc.).

In order to ensure the operation of the sensor (COI sensor) in the range of large bending radii in FIG. Figure 3 shows an example of the operation of the sensor, in which the sensor element is made in the form of a bay (2) of an optical fiber with two grippers (3) located at the edges of the bay. One of the grips is fixed on the fixed part of the sensor housing, and the second on the movable part, moved by the working body of the sensor.

In this design, the energy of the probe pulse is absorbed during compression of the bay twice in each turn of the ellipsoid deformation of the optical fiber of the SE of the sensor, which can significantly increase the minimum value of the bend radius of the ellipse, at which the probe pulse energy is completely absorbed. The grips are made in the form of two heat-shrink tubes of different diameters inserted into each other, which are designed: one to hold the bay, the second to capture the first and form the mounting hole designed to attach the bay to the movable and fixed parts of the sensor.

In FIG. Figure 4 shows an example of the operation of the sensor, in which the sensor element is made in the form of two bays (2) of optical fiber with three grippers (3) - two at the edges on each and one common in the middle. The general grip is fixed on the fixed part of the sensor housing, and the other two on the moving part, moved by the working body of the sensor. The distance between the extreme grips should ensure the complete release of one ring to the size of the circle and compression of the second ring to an ellipse of the desired shape and vice versa in a different position of the sensor. The operation of the sensor is similar to the operation of the sensor of the previous version, except that the reflection signals from different rings of the sensor are inverse to each other, which provides continuous diagnosis of the health of the sensor by two reflection signals. Additionally, the state of the sensor can be read by two independent reflectometers taking into account the inversion of the signals. According to FIG. 4. the sensitive part of the sensor is made in the form of two bays of optical fiber with grips attached to the body of the sensor and to the movable part of the working body to obtain dynamic information about the oscillations of the inertial working body.

In FIG. 5 shows an example of a sensor operation in which the sensor element is made in the form of two bays of optical fiber with two common grips at the edges. One grip is fixed on the fixed part of the sensor housing, and the other on the movable part, moved by the working body of the sensor. The distance between the extreme positions of the grips should ensure complete release of the rings to the size of the circle and the compression of both rings to the size of the ellipse of the desired shape. The operation of the sensor is similar to the operation of the sensor with one ring, but with two independent rings, which provides continuous diagnosis of the health of the sensor by two reflection signals. Additionally, the state of the sensor can be read by two independent reflectometers. According to FIG. 5, the sensitive part of the sensor is made in the form of two bays of optical fiber with grips attached to the body of the sensor and to the movable part of the working body with independent terminals of the optical fiber for parallel operation with one sensor.

The construction of several CFI in a serial chain allows you to use a small part of the power of the probe pulse and deliver the energy of the return signals to the receiving device as efficiently as possible, providing the ability to connect the maximum number of sensors on one line of the device.

Description of the operation of the sensitive part of the CFI.

Optical cores of a cable, pigtails or patch cords serve as a sensitive part of CFI with a variable radius of bending of the fiber. Cable fibers and return movements of the working body provide the required long-term elasticity necessary when restoring the original shape of the core of the sensitive part of the optical sensor.

The principle of operation of the sensor is illustrated in FIG. 1 and 2.

Description of the operating principle of the CFI.

The probe pulse from the OTDR passes through the transport part of the fiber optic circuit to the sensitive part of the CFI. In one of the provisions of the working organ of the CFI, with the values of the bending radii of the fiber of the sensitive part being more critical, at which the energy of the laser pulse begins to partially penetrate into the fiber sheath, the laser pulse propagates in the fiber with practically no additional losses (without taking into account the natural attenuation in the fiber medium).

With any method of generating a reflection or return signal described in the drawings in this position of the working element of the CFI, the reflection signal will be fed to the input of the receiving device, signaling the presence of a reflection signal from a specific sensor with a certain time delay. When the position of the working organ of the CFI is changed and the bending radius of the fiber in the elastic range is less than the critical value, at which the probe pulse, reaching the point of bending of the fiber, begins to penetrate into the fiber sheath and is absorbed in it, as a result of which the signal does not pass through a closed loop and does not reflect formed.

Claims (6)

1. The end fiber optic detector (CFI), comprising a housing with a working body, providing a change in the position of the optical fibers of the sensitive part of the CFI, the sensitive part, which is installed in the frame of the CFI and connected to the transport part, providing the connection of the CFI to the branched optical network and the transportation of laser pulses in forward and reverse direction, characterized in that the sensitive part is made of optical fibers and a splitter, the outputs of which are closed between themselves by an optical fiber and an image by a closed loop to form a reflection signal, wherein the change in the geometrical position of the fiber in the sensitive part of the koi in the elastic deformation range due to changes in the position of working body such that lead to changes in the possibility of forming the reflection and transmission signals. 2. The terminal fiber-optic detector according to claim 1, characterized in that the sensitive part of the COI is a closed loop in the form of rings with a bending radius in the elastic range of deformations, allowing free passage of the reflection signal of the probe pulse in one of the positions of the working body and the bending radius of the rings in the elastic range of deformations in the second position of the working body to the form in which the signal of the probe pulse is absorbed in parts in the sheath of the optical fiber of the sensitive part of the CFI in places with the smallest their radii to the required minimum value of the reflection signal. 3. The terminal fiber-optic detector according to claim 1, characterized in that the sensitive part of the CFI is a closed loop in the form of optical fibers, rolled into rings and installed in the frame of the CFI so that in one of the positions of the working body one ring is in a state, allowing free passage of the probe pulse signal, and other rings in a state in which the probe pulse signal is partially absorbed in the optical fiber cladding of the sensitive part of the CFI in places with the smallest radii d about the required minimum value of the reflection signal, and in the second position of the working body, the positions of the rings are reversed, providing an inverse state of the reflection signals. 4. The terminal fiber-optic detector according to claim 1, characterized in that the sensitive part of the CFI is a closed loop in the form of optical fibers, rolled into rings and installed in the frame of the CFI so that two groups of rings are fixed on one side on the fixed part of the housing, and the second sides of the rings are connected with each other and with a freely hanging movable working body, while the planes of the groups of rings are located in mutually perpendicular planes, providing the possibility of automatic retention of the rings in control goy deformation in a counter force without retraction in the side of the movable load position, compressed to a degree of the average level of energy absorption of the probe pulse in each group of rings, providing dynamic change in reflection signals depending on the magnitude of the acceleration transmitted to the housing koi. 5. The terminal fiber optic detector according to any one of paragraphs. 2-4, characterized in that the spatial shape of the optical fiber of the sensitive part of the CFI is changed through the grips located on opposite sides of the rings of the sensitive element, some of the grips are connected to the moving part of the working body of the CFI, others to the base of the CFI body. 6. The terminal fiber optic detector according to claim 5, characterized in that the grippers are made in the form of segments of heat shrink tubes of different diameters inserted into each other, some are designed to hold optical fibers rolled into rings, an optical bay, others to capture the first and forming a mounting hole for attaching an optical bay to the movable and fixed parts of the CFI.

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