CN2715126Y - Optical fiber inclination sensor - Google Patents

Abstract

The utility model relates to an optical fiber inclination sensor. The body of the sensor is a container which contains liquid inside, and the surface of the liquid has high reflectivity or floats a floater which is plated with a reflectance coating. The container is sealed by a cover plate. A couple of fiber optic probe fixing seats are arranged on the cover plate, and a couple of fiber optic probes which are arranged in the same direction with the measurand are positioned on the cover plate. The end surface of the fiber optic probes and the surface of the liquid with high reflectivity or the surface of the floater form two Fabry-Perot cavities. The fiber Fabry-Perot interference technique is used to measure the changes of the liquid level. The utility model obtains the slope angle of the measurand, enhances the measuring accuracy and avoids the electromagnetic interference. The signal demodulation dispenses with the special secondary instrument for the long transmission distance, which reduces the measuring cost. It has simple structure.

Description

The slant optical fiber sensor

Technical field

The utility model relates to a kind of Fibre Optical Sensor that is used for the building structure health monitoring.

Background technology

In monitoring to heavy construction installation security situation, angle of inclination to bridge pier, girder etc. is measured, can be by calculating the displacement that obtains bridge pier, the important informations such as amount of deflection of beam, therefore the structure of heavy construction facility being carried out angle of bank measurement, is one of main method of bridge structural state monitoring.And a large amount of what use is inclinator to angle of bank measurement, and it is to be purpose with the characteristic curve of measuring deformation point on the deformable body with respect to the angular deflection of basic vertical line (or basic levelling line).Existing inclinator mainly contains mechanical type or electrical type, in product in the market, classify by principle of work, mainly contain electrolyte type, type vibration wire and force balance type, they contain electronic sensor device and remote control device more, have easy for installationly, use and to establish benchmark flexibly, easily, can be fit under the rugged surroundings advantages such as for a long time automatic work.But also there are some shortcomings separately simultaneously, mainly show as the following aspects:

(1) complex structure, the ratio of performance to price is low

(2) electric class surveying instrument, measuring accuracy and long-time stability are vulnerable to the influence of power-supply fluctuation

(3) anti-electromagnetic interference (EMI), corrosion-resistant, moisture resistance ability

(4) can not merge with fibre-optic transmission system (FOTS), signal transmission distance is short

(5) need special secondary instrument, be unfavorable for merging with the fibre optic strain sensor system

Above-mentioned shortcoming causes existing inclinator to be not suitable for using in the long-term on-line monitoring of building structure.

Summary of the invention

The purpose of this utility model just is the shortcoming at the inclinator existence of using in the long-term on-line monitoring of existing building structure, and provide a kind of slant optical fiber sensor, utilize Fabry-perot optical fiber interference technique measuring liquid level to change, improve measuring accuracy, avoid electromagnetic interference (EMI), transmission range is long, and is simple in structure.

This slant optical fiber sensor is mainly based on the principle of optical fiber F-P sensor, its main body is a container, dress liquid in the container, liquid surface has highly reflective or the floating float that a plating reflectance coating is arranged, container top seals with metal cover board, cover plate is provided with two fibre-optical probe holders, and two fibre-optical probes have been installed, and it is consistent that two fibre-optical probe orientations and measurand are tilted to direction.Its principle constitutes two Fa-Po cavities respectively with the end face and the float surface of two fibre-optical probes shown in Fig. 1 (a), when container is in horizontality, and the initial cavity appearance in two FP chambeies etc., i.e. h ₁=h ₂=h ₀The small angle θ if container tilts along clockwise direction, shown in Fig. 1 (b), h ₁' ≠ h ₂', chamber, two FP chambeies is long does not wait.Utilize general optical fiber Fabry-Perot sensor demodulating equipment to measure h by instrumentation ₁' and h ₂', under the very little situation in angle of inclination (usually less than 1 °), and can calculate according to geometric relationship:

$\mathrm{tg\θ}=\frac{h_2^{\′}-h_1^{\′}}{d}------------------\left(1\right)$

Thereby try to achieve

$\mathrm{\θ}=\mathrm{arctg}\frac{h_2^{\′}-h_1^{\′}}{d}---------------------\left(2\right)$

When θ is very little, can be similar to and obtains

$\mathrm{\θ}\≈\mathrm{tg\θ}=\frac{h_2^{\′}-h_1^{\′}}{d}--------------------\left(3\right)$

Vergence direction depends on the positive and negative of θ value, and θ is timing, and the inclination angle is a clockwise direction; When θ was negative, the inclination angle was counterclockwise.

This slant optical fiber sensor on the cover board also is provided with the liquid feeding aperture, can add liquid by aperture, adjusts the initial long h in chamber ₁=h ₂=h ₀, make initial cavity cover with the requirement of sufficient optical fiber Fabry-Perot sensor demodulating equipment; After adjustment finished, aperture can seal.Container bottom also is provided with to install adjusts screw, is used for installing level-off.

Further, on the cover board with respect to last to establishing another on the other direction of fibre-optical probe holder to the fibre-optical probe holder, and another is installed to fibre-optical probe, and constitute two Fa-Po cavities in addition with highly reflective liquid level or float surface, can realize two-dimentional inclination measurement thus.

The major advantage of this slant optical fiber sensor:

(1) utilize Fabry-perot optical fiber interference technique measuring liquid level to change, adopt the float of optical fiber and high reflection to constitute Fa-Po cavity, both guaranteed the signal quality of sensor, the interference of having avoided the liquid surface fluctuation to bring again, the measuring accuracy height, good stability, simple in structure;

(2) adopt optical fiber technology, be not subjected to electromagnetic interference (EMI), corrosion-resistant, moisture resistance;

(3) can with the seamless fusion of fibre-optic transmission system (FOTS), transmission range is long, is fit to the long-term on-line monitoring of building structure more;

(4) the signal demodulation of this sensor only need be adopted general optical fiber Fabry-Perot sensor demodulating equipment, need not special secondary instrument, helps constituting the large-scale optical fiber test network with Fabry-perot optical fiber strain sensor, fiber optic fabry perot temperature sensor etc.;

(5) increase by two fibre-optical probes at other direction, also can easily realize two-dimentional inclination measurement, do not changing sensor construction, do not increase under the prerequisite of measuring cost, expand the application space of sensor greatly.

Description of drawings

Fig. 1 is the structural representation of this slant optical fiber sensor; Wherein a is the structure of heeling condition not; The structure of b heeling condition;

Fig. 2 is a slant optical fiber sensor top view of realizing two-dimentional inclination measurement.

Embodiment

Referring to Fig. 1, the main body of slant optical fiber sensor is a container 5, dress liquid 7 in the container, and liquid surface has the float 6 of a plating reflectance coating, and container top seals with metal cover board 4, and cover plate is provided with two fibre-optical probe holders 2, and two fibre-optical probes 1 have been installed.End face and float 6 surfaces with two fibre-optical probes 1 constitute two Fa-Po cavities respectively.Container 5 bottoms also are provided with to install adjusts screw 8, is used for installing level-off.

Referring to Fig. 2, the slant optical fiber sensor also can be used to realize two-dimentional inclination measurement, what need change is on the basis of Fig. 1 structure, at cover plate 4 upper edge directions Xs and Y direction fibre-optical probe 1-X and the 1-Y that pair of angled is measured is set respectively respectively, the end face of such two groups of fibre-optical probes and float 6 surfaces constitute two groups of i.e. four Fa-Po cavities respectively on directions X and Y direction, record the inclination situation of directions X and Y direction respectively, realize two-dimentional inclination measurement.

Although the foregoing description has adopted the float 6 and the fibre-optical probe that are coated with reflectance coating to constitute Fa-Po cavity, but still can utilize liquid level (as mercury) of other high reflection to constitute Fa-Po cavity, thereby realize the utility model and do not deviate from claims defined and use novel essence and scope in fibre-optical probe.

Claims (4)

1, slant optical fiber sensor, it is characterized in that: the main body of sensor is a container (5), dress liquid (7) in the container, liquid surface has highly reflective or the floating float (6) that a plating reflectance coating is arranged, container seals with metal cover board (4), cover plate is provided with a pair of fibre-optical probe holder (2), and a pair of orientation and the consistent fibre-optical probe (1) of measurand tendency direction are installed, and the end face of fibre-optical probe (1) and highly reflective liquid level or float (6) surface constitute two Fa-Po cavities respectively.

2, slant optical fiber sensor according to claim 1, it is characterized in that: on the cover board with respect to last to also being provided with another on the other direction of fibre-optical probe holder to the fibre-optical probe holder, and another is installed to fibre-optical probe, constitute two Fa-Po cavities in addition with highly reflective liquid level or float (6) surface.

3, slant optical fiber sensor according to claim 1 and 2 is characterized in that: cover plate is provided with liquid filling hole (3).

4, slant optical fiber sensor according to claim 1 and 2 is characterized in that: container (5) bottom is provided with to install adjusts screw (8).