JP2001093074A - Condition monitoring sensor and optical remote monitoring system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable a single sensor using an optical fiber to grasp the operation state of an object to be monitored in detail. SOLUTION: A plurality of sensor units 7 for providing a fixed amount of light transmission loss to an optical fiber 6 by a pressurizer 7a are provided in one sensor. Also, the input shaft 1 that moves according to the movement of the monitoring target 10
The cam 2 for operating the pressurizing element 7a is provided in
Is switched by the displacement of the input shaft (rotation in the figure).
When the optical transmission loss distribution measuring device detects which sensor section is operating in this way, the operating state of the monitoring target can be determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a condition monitoring sensor used for remotely monitoring the operating state of various objects using an optical fiber, and an optical remote monitoring system using the sensor.

[0002]

2. Description of the Related Art For example, when remotely monitoring the opening / closing status of a floodgate, a valve, and the like at a plurality of points, an electric sensor is conventionally used.
A point 1 sensor and information conversion and transmission equipment are required, and a power source is required on site, which complicates the construction of a monitoring system and is subject to installation regulations.

On the other hand, a system for performing multipoint monitoring using an optical fiber sensor has an advantage that a system can be constructed even without a power supply at a site (monitoring point), and information conversion and transmission devices are not required. . The monitoring system using this optical fiber sensor is a relatively new technology, which uses the displacement of the monitored object to distort the optical fiber and measures the distortion with an optical strain distribution measuring device to determine the state of occurrence of displacement, etc. And the place of occurrence.

[0004]

A conventional monitoring system using an optical fiber sensor detects a specific state based on ON / OFF signals of the sensor. For example, if the sensor is ON, it is determined that the valve is closed, and if it is OFF, it is determined that the valve is open. However, only the ON and OFF signals do not allow a detailed grasp of how much the valve is open.

Further, if a plurality of sensors are installed at one point in order to grasp the detailed situation, the number of fusion points for connecting the sensors increases, the transmission loss of the optical fiber increases, and the distance of the optical fiber of one system increases. And the number of points that can be monitored by the same system decreases.

An object of the present invention is to provide a state monitoring sensor using an optical fiber which has solved the above-mentioned problem and an optical remote monitoring system using the sensor.

[0007]

In order to solve the above problems, according to the present invention, optical transmission loss is forcibly given to a part of an optical fiber in accordance with the movement of an object to be monitored.
The state and position of occurrence of the transmission loss are monitored using an optical transmission loss distribution measuring device (OTDR: a device for measuring the transmission loss distribution of each part in the length direction of the optical fiber).

In order to provide an optical fiber with an optical transmission loss in accordance with the movement of the object to be monitored, a sensor unit for applying a quantitative optical transmission loss to the optical fiber by pressing the optical fiber with a pressurizer; An input shaft provided with a cam for operating the pressurizer, and a transmission mechanism for transmitting the movement of the monitored object to the input shaft as rotation or linear movement, wherein the sensor unit is provided with one sensor in the longitudinal direction of the optical fiber. A plurality of sensors are provided at different positions, and a state monitoring sensor is used in which the state of imparting optical transmission loss to the same optical fiber by the plurality of sensor units is switched by the displacement of the input shaft.

In this sensor, it is preferable that a second transmission mechanism, such as a lever, capable of transmitting the momentum by changing the momentum at a predetermined ratio is interposed between the cam and the pressurizing element. When the second transmission mechanism is a lever, it is preferable that the lever is formed of a material having spring elasticity.

Further, although the input shaft may be a slide shaft,
The input shaft is used as a rotation shaft, and a plurality of cams corresponding to the number of sensor units are provided on the outer periphery of the shaft, and latches are latched in grooves provided on the outer periphery of the input shaft so that the input shaft can be switched at each state switching point. It is preferable to provide a positioning means for positioning, since it is easy to adjust the positions of the components, and it is easy to unitize the sensor.

When this condition monitoring sensor is serially connected to an optical fiber laid through a plurality of monitoring points and installed at each monitoring point, and further, an optical transmission loss distribution measuring device is connected to the optical fiber. The optical remote monitoring system of the invention can be realized.

[0012]

According to the present invention, a single sensor is provided with a plurality of sensor sections for providing optical transmission loss quantitatively at different positions with respect to the same optical fiber, and the displacement of an input shaft that moves in accordance with the movement of the monitored object is provided. Since the state of the transmission loss in each sensor unit is switched, the operating state of the monitoring target can be grasped in detail depending on which sensor unit is operating.

Further, since a plurality of sensor units each of which is comparable to a conventional optical fiber sensor are provided in one sensor,
The number of fusion spliced portions of the optical fiber at the monitoring point is reduced, and optical transmission loss due to fusion is reduced. Therefore, the monitoring distance of a series of systems can be increased, and the number of monitoring points can be increased.

Further, the input shaft and the plurality of sensor sections can be integrated, and the integration (unitization) can simplify the installation work on site and reduce the part depending on the skill of the operator.

In addition, a method of measuring the distribution of the strain by giving a fixed amount of strain to the optical fiber makes it possible to monitor the state in detail by providing a plurality of sensor units in one sensor. Measurement takes time. Further, an expensive optical strain distribution measuring device is required, and the sensor becomes complicated and large. On the other hand, the sensor and system of the present invention apply a transmission loss to the optical fiber and measure the loss distribution, so that the complex described here is also eliminated.

The operation and effect of the preferred sensor structure will be described in the next section.

[0017]

FIG. 1 shows an embodiment of a state monitoring sensor according to the present invention. In the drawing, reference numeral 1 denotes an input shaft supported by a bearing (not shown) so as to be rotatable at a fixed position. This input shaft 1
Are provided with a plurality of cams 2 and positioning grooves 3. Further, a pin 4 extending radially is attached to the outer periphery of one end.

Reference numeral 5 denotes a lever provided corresponding to each of the cams 2, reference numeral 6 denotes a single-core optical fiber, and reference numeral 7 denotes a pressure unit 7a which is a sensor unit for causing a quantitative optical transmission loss in the optical fiber 6. The sensor units 7 are provided in the same number as the cams 2.

FIG. 2 shows the internal structure of the exemplary sensor unit 7. The illustrated sensor unit 7 draws an optical fiber 6 into a housing 7c having a fiber support point 7b, and presses and deforms the optical fiber 6 between two fiber support points by a pressurizer 7a. As shown in FIG. 7, it is preferable that the number of pressure points by the fiber support points 7b and the pressure elements 7a be increased and the optical fiber 6 be deformed under pressure at a plurality of locations. When the required optical transmission loss is generated at multiple points, the strain applied to the optical fiber may be smaller than when the required optical transmission loss is generated at one point, and unnecessary force is not applied to the optical fiber. The lever 5 swings while being held down by the cam 2, and pushes and moves the pressurizing element 7a. The pressing element 7a pressed by the lever 5 is shown in FIG.
As shown in (b), the optical fiber 6 in contact with the tip is deformed, and the deformation causes a light transmission loss in the optical fiber 6.

Incidentally, the cams 2 may be arranged without an interval. Further, the numbers of the cams 2 and the sensor portions 7 can be freely increased as needed.

The pressurizing element 7a is formed by deforming a part of the housing 7c and integrally forming the housing 7c.
Either one of which has a hole in c and is slidably inserted into the hole may be used. If the pressurizing element 7a is restored by the elastic restoring force of the optical fiber 6 or the elastic restoring force of the housing 7c, a return spring is not required, which is advantageous in terms of assembling the strain applying section 7 and cost.

FIG. 3 shows a mechanism for positioning the input shaft 1 at each point of state switching. In this positioning mechanism, a latch 8 formed of a leaf spring is locked in a groove 3 provided on the outer periphery of the input shaft 1 at a constant pitch, and the input shaft 1 is positioned at that position. When a rotational force equal to or more than a predetermined value is applied, the input shaft 1 rotates by bending the leaf spring 8.

Reference numeral 10 in FIG. 1 denotes an object to be monitored that moves in the direction of the arrow. Here, two pins 9 are attached to this monitoring target 10.
And the pin 9 and the pin 4 on the outer periphery of the input shaft convert the linear motion of the monitored object 10 into a rotary motion and transmit it to the input shaft 1, but the transmission mechanism employed is not limited to this.

As shown in FIG. 4, the input shaft 1 is a non-rotating slide shaft, and the shaft is slid by a force transmitted from a monitored object via a link mechanism or the like to provide a cam provided on the outer periphery of the shaft. The same object can be achieved even with a sensor structure that presses the pressurizing element 7a of the sensor unit 7 with 2. According to this structure, when the slide stroke of the input shaft 1 can be increased, the pressurizers of the respective sensor units can be sequentially operated by one cam 2. The state monitoring sensor of FIG. 4 also preferably has a second transmission mechanism such as a lever interposed between the cam 2 and the mover 7a.

As the mechanism, the effects when a lever is interposed are listed below. When the cam is brought into direct contact with the pressure member of the sensor section, sliding wear of the pressure member occurs, and the amount of distortion varies. Therefore, it is necessary to take measures to prevent the wear of the pressurizer, but such a device is not required if a lever is used. Since the direction in which the force is applied to the pressure element is substantially the same as the direction in which the pressure element advances and retreats due to the presence of the lever, no excessive force is applied to the pressure element, and the operability of the pressure element does not deteriorate. By adjusting the leverage, small movements of the input shaft can be amplified and given to the pressurizer, and excessive movements can be reduced and transmitted, and conversely, sensor sensitivity improvement, protection, miniaturization, etc. The degree of freedom of correspondence increases. When the lever is formed of a leaf spring or the like, an excessive force is not applied to the sensor unit even when the operation amount fluctuates due to a buffering effect due to the elastic deformation of the lever. Since an appropriate space can be maintained between the input shaft and the sensor unit by leverage, watertight sealing on the sensor unit side can be easily performed.

Next, an embodiment of an optical remote monitoring system according to the present invention using the above-described state monitoring sensor will be described.

FIG. 5 shows an outline of the gutter monitoring system. Reference numeral 11 in the figure denotes a gutter gate, and the opening of the gutter gate 12 is adjusted to control the flow rate of the gutter pipe. In order to monitor the opening state of the gate, a state monitoring sensor S is provided at each gutter gate position. Further, a series of optical fibers 13 are laid through each monitoring point, and an optical transmission loss distribution measuring device (OTDR) 14 is connected to one end of the optical fiber 13 drawn into a monitoring station or a relay station. Measuring device 14
A processing device 15 for processing the measured data and grasping the opening state of the gate is connected.

In the condition monitoring sensor S, the optical fiber (6 in FIG. 6) of the sensor is serially connected to the optical fiber 13. Although a part of the optical fiber 13 can be used as an optical fiber of the sensor, since this structure requires a sensor assembly on site, if the optical fiber of the sensor is fusion-spliced using a unitized sensor, Good.

FIG. 6 shows the operating state of the state monitoring sensor in the system of FIG. In the sensor S used here, two sensor units 7 _-1 and 7 _-2 are operated by two cams 2 _-1 and 2 _-2 provided on the input shaft 1 (the rotating shaft in the figure).

[0030] in FIG. 6 (I) is when you fully open the gates 12, pressurizer 7a of the sensor unit _7-1 is operating by being pushed by the cam 2 _-1. (II) is when the gate 12 is half-open, and both the sensor units 7 _-1 and 7 _-2 are in the inactive state. or,
(III) is when the gate 12 is fully opened, and the sensor unit _7-1 is operating. Therefore, the open state of the gate 12 can be determined from the operating states of the two sensor units 7 _-1 and 7 _-2 .

Here, since the number of sensor units of one sensor is set to 2, the half-open state is determined based on the fact that both sensor units are in the inactive state. If it is set, the half-opening can be grasped more accurately. Further, if the number of sensors is further increased, the gate 12
The opening state of the door can be grasped in more detail, and the opening degree of the door can be managed.

[0032]

As described above, when the state monitoring sensor of the present invention is used, the operating state of the monitored object can be grasped finely by one sensor.

Further, since a plurality of sensor units are provided in one sensor, the number of optical fiber fusion splicing parts at the monitoring points is reduced to extend the monitoring extension, and the number of monitoring points by one system is increased. Can be.

Furthermore, since the components can be integrated into one unit and the sensor can be unitized, installation on site is also facilitated, the part depending on the skill of the operator is reduced, and the reliability of the monitoring system is increased. It becomes possible.

In addition, the one in which a lever or the like is interposed between the cam and the pressurizing element of the sensor unit can prevent the pressurizing element from being worn or malfunction due to the direct contact of the cam. In addition, the movement of the input shaft can be amplified or reduced to be transmitted to the pressurizer, and the degree of freedom in setting the sensitivity of the sensor can be increased. Further, it is advantageous in terms of protection of the sensor unit and prevention of watertightness.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of a condition monitoring sensor of the present invention.

2A is a cross-sectional view showing the sensor unit of the sensor of FIG. 1 in a non-operating state; FIG. 2B is a cross-sectional view showing the sensor unit of the sensor of FIG. 1 in an operating state;

FIG. 3 is a diagram showing an example of an input shaft positioning mechanism.

FIG. 4 is a diagram showing a main part of another embodiment of a state monitoring sensor.

FIG. 5 is a diagram showing an outline of an example of an optical remote monitoring system according to the present invention.

FIG. 6 is a diagram showing an operation state of a state monitoring sensor in the system of FIG. 5;

FIG. 7 is a perspective view showing a preferred example of a pressure element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Cam 3 Groove 4 Pin 5 Lever 6 Optical fiber 7 Sensor part 7a Pressurizer 8 Leaf spring 9 Pin 10 Object to be monitored 11 Gutter 12 Gate 13 Optical fiber 14 Optical transmission loss distribution measuring device 15 Processing device S State monitoring Sensor

Claims (5)

[Claims] 1. A sensor unit for applying a pressure to an optical fiber with a pressurizer to provide a quantitative optical transmission loss, an input shaft provided with a cam for operating the pressurizer, and a monitoring target on the input shaft. A transmission mechanism for transmitting the movement of an object as rotation or linear movement, wherein a plurality of the sensor units are provided in one sensor at different positions in the longitudinal direction of the optical fiber, and the plurality of sensor units are connected to the same optical fiber. A state monitoring sensor in which the optical transmission loss applying state is switched by the displacement of the input shaft. 2. The condition monitoring sensor according to claim 1, further comprising a second transmission mechanism interposed between the cam and the pressurizer, the second transmission mechanism being capable of changing and transmitting the momentum at a predetermined ratio. 3. The condition monitoring sensor according to claim 2, wherein a lever is employed as the second transmission mechanism, and the lever is formed of a material having spring elasticity. 4. The input shaft is a rotating shaft, a plurality of cams corresponding to the number of sensor units are provided on the outer periphery of the shaft, and a latch is locked in a groove provided on the outer periphery of the input shaft to keep the input shaft in a state. 4. The state monitoring sensor according to claim 1, further comprising positioning means for positioning at each switching point. 5. The state monitoring sensor according to claim 1, which is serially connected to an optical fiber laid through a plurality of monitoring points and installed at each monitoring point.
An optical transmission loss distribution measuring device is connected to the optical fiber, and the presence / absence of optical transmission loss of the optical fiber at each monitoring point and the fluctuation state of the transmission loss occurrence position are monitored to grasp the operation state of the monitored object at each monitoring point. Optical remote monitoring system.