CN211085513U - Humidity FBG probe, temperature and humidity FBG probe and measurement system - Google Patents
Humidity FBG probe, temperature and humidity FBG probe and measurement system Download PDFInfo
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- CN211085513U CN211085513U CN202020183483.4U CN202020183483U CN211085513U CN 211085513 U CN211085513 U CN 211085513U CN 202020183483 U CN202020183483 U CN 202020183483U CN 211085513 U CN211085513 U CN 211085513U
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Abstract
The utility model relates to a humidity FBG probe, humiture FBG probe and measurement system, including base, carbon fiber strip and the moisture sensitive metal hairspring who coils the ruler form from inside to outside in proper order, the base is used for realizing the support. The humidity-sensitive metal hairspring is characterized in that one end, located at the inner ring, of the humidity-sensitive metal hairspring is fixed with the base, one end, located at the outer ring, of the humidity-sensitive metal hairspring is a movable end, and the humidity-sensitive metal hairspring is different in stress under different humidity, so that the humidity-sensitive metal hairspring deforms along the winding direction. One end of the carbon fiber strip is fixed with the base, the other end of the carbon fiber strip is suspended relative to the base, a flexible FBG is fixedly arranged on the carbon fiber strip, and the flexible FBG can synchronously deform along with the carbon fiber strip; the expansion end of the moisture-sensitive metal balance spring is connected with one end of the carbon fiber strip in a suspension mode, so that the moisture-sensitive metal balance spring can transmit deformation generated by self due to humidity change to the carbon fiber strip, the flexible FBG can be synchronously deformed along with the carbon fiber strip, and the wavelength of laser in the flexible FBG is changed and input.
Description
Technical Field
The utility model belongs to the technical field of the sensor, concretely relates to humidity FBG probe, humiture FBG probe and measurement system.
Background
In the market today, the electronic temperature and humidity sensor is still dominant in the market due to its advantages of low cost, fast response speed, convenient signal processing, etc. However, the electronic sensor has the disadvantages of poor interchangeability, insufficient long-term stability and the like, and is difficult to be applied to the fields of electrical power, petrochemical industry and the like with flammable and explosive severe environments.
The fiber grating type temperature and humidity sensor is a novel temperature and humidity sensor developed along with an optical fiber communication technology, and compared with the traditional electrical temperature and humidity sensor, the temperature and humidity sensor has the advantages of electromagnetic interference resistance, good electrical insulation, large dynamic range and the like, and a sensing part is light in weight, small in size, diversified in structure and geometric shape, and easy to multiplex networking to realize real-time, online and distributed sensing.
The inventor knows that the optical fiber sensor is used as a temperature and humidity sensing element at present, and a temperature and relative humidity sensing probe is formed by a dry method and a wet method, so that the sensing element can be made into a full optical fiber, but the probe is complex to maintain in the later period, and a wet environment is produced by adding water. In some technical schemes, the exterior of the fiber bragg grating or the multimode fiber is coated with a humidity sensitive material, and the humidity can also be measured. But the process has strict requirements on the material and thickness of the coating layer. The production of the humidity-sensitive sensor can cause low product qualification rate and higher cost. The humidity sensor adopting the multimode optical fiber mode cannot measure humidity at a long distance.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a humidity FBG probe, humiture FBG probe and measurement system can solve the maintenance loaded down with trivial details, the low scheduling problem of qualification rate of current humidity sensor, temperature and humidity sensor.
In order to achieve the above object, a first aspect of the present invention provides a humidity FBG probe, which comprises a base, a carbon fiber strip and a moisture-sensitive metal balance spring wound in a coil ruler shape from inside to outside in sequence, wherein the base is used for supporting.
The humidity-sensitive metal hairspring is characterized in that one end, located at the inner ring, of the humidity-sensitive metal hairspring is fixed with the base, one end, located at the outer ring, of the humidity-sensitive metal hairspring is a movable end, and the humidity-sensitive metal hairspring is different in stress under different humidity, so that the humidity-sensitive metal hairspring deforms along the winding direction.
One end of the carbon fiber strip is fixed with the base, the other end of the carbon fiber strip is suspended relative to the base, a flexible FBG is fixedly arranged on the carbon fiber strip, and the flexible FBG can synchronously deform along with the carbon fiber strip; the expansion end of the moisture-sensitive metal balance spring is connected with one end of the carbon fiber strip in a suspension mode, so that the moisture-sensitive metal balance spring can transmit deformation generated by self due to humidity change to the carbon fiber strip, the flexible FBG can be synchronously deformed along with the carbon fiber strip, and the wavelength of laser in the flexible FBG is changed and input.
As a further limitation of the first aspect of the present invention, the region where the two ends of the flexible FBG do not have the grating is a connecting section, and the connecting section is used for connecting the carbon fiber strips.
As a further limitation of the first aspect of the present invention, the extending direction of the carbon fiber strip is the same as the extending direction of the flexible FBG, and the moisture-sensitive metal hairspring is disposed on one side of the carbon fiber strip which is suspended relative to the base.
A second aspect of the present invention provides a temperature and humidity FBG probe, comprising the humidity FBG probe and a temperature compensation FBG, wherein the temperature compensation FBG is supported by a base, and the temperature compensation FBG can generate deformation along the extending direction of the temperature compensation FBG when the temperature changes, so as to change the laser wavelength passing through the temperature compensation FBG;
the temperature compensation FBG and the flexible FBG are connected in series in the same optical fiber.
The third aspect of the utility model provides a temperature and humidity measurement system, include humiture FBG probe, the one end of optic fibre is connected with laser generating device, and the other end is connected with laser signal processing equipment, laser signal processing equipment can be according to the change of laser wavelength, reachs the information of base department temperature and humidity.
The beneficial effects of one or more technical schemes are as follows:
(1) the FBG for the temperature and the humidity of the fiber bragg grating which is etched on the fiber as a sensing element is utilized to form the sensing probe, so that a non-source and full-photochemical sensing terminal can be realized, and the FBG has the advantages of safety and reliability when being used in an electromagnetic sensing occasion.
(2) The wavelength division multiplexing function can be realized by utilizing the wavelength distinguishing characteristic of the fiber bragg grating temperature sensor, and the fiber bragg gratings used by a plurality of temperature and humidity sensing probes have different central wavelengths and can be connected in series on the same optical fiber to realize the wavelength division multiplexing.
(3) Two fiber bragg grating temperature sensors which are same in specification and packaged through temperature sensing are integrated in the probe, one fiber bragg grating temperature sensor is used as a dry end sensor and placed in the air for measuring an environment temperature value, the other fiber bragg grating sensor is placed on a flexible carbon fiber strip, a humidity-sensitive metal balance spring is used as a flexible force changing piece, when the environment relative humidity changes, the temperature value measured by the temperature sensor and the flexibility measured by the humidity sensor cause optical wavelength change, the value is in a proportional relation with the relative humidity in the air, and the relative humidity value in the environment can be obtained through conversion of the proportional relation.
(4) Temperature and humidity information sensed by the fiber grating temperature and humidity sensing probe is reflected by the change of the central wavelength of the fiber grating temperature and humidity information, the wavelength change can be converted into the wavelength change of laser input to the probe by a remote light source, and the laser carrying the temperature and humidity information can be remotely transmitted back to remote signal processing equipment through a transmission optical fiber to carry out temperature and humidity data calculation.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.
Fig. 1 is a schematic view of the overall structure in embodiment 2 of the present invention;
in the figure: 1. a base; 2. a moisture sensitive metal hairspring; 3. a flexible FBG; 4. temperature compensation FBG; 5. carbon fiber strips; 6. a dust-proof cover.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
For convenience of description, the words "up, down, left, right" in the present invention, if appearing, are intended to correspond only to the upper, lower, left, right directions of the drawings themselves, not to limit the structure, but merely to facilitate the description of the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the invention.
Example 1
As shown in fig. 1, the present embodiment provides a humidity FBG probe, which includes a base 1, a carbon fiber strip 5 and a humidity-sensitive metal balance spring 2 wound in a coil form from inside to outside, wherein the base 1 is used for realizing support. The humidity-sensitive metal hairspring 2 is fixed to the base 1 at one end of the inner ring, the humidity-sensitive metal hairspring 2 at one end of the outer ring is a movable end, and the humidity-sensitive metal hairspring 2 is different in stress under different humidity, so that the humidity-sensitive metal hairspring 2 deforms.
One end of the carbon fiber strip 5 is fixed with the base 1, the other end of the carbon fiber strip is suspended relative to the base 1, a flexible FBG3 is fixedly arranged on the carbon fiber strip 5, and the flexible FBG3 can synchronously deform along with the carbon fiber strip 5; the expansion end of moisture-sensitive metal balance spring 2 is connected with the unsettled one end of carbon fiber strip 5 to make moisture-sensitive metal balance spring 2 can transmit the deformation that self produced because of humidity changes for carbon fiber strip 5, it can take place synchronous deformation along with carbon fiber strip 5 to warp FBG3, with the wavelength of laser in the change input warp FBG 3.
The areas of the flexible FBG3 without gratings at both ends are connection segments for connecting the carbon fiber strips 5. The extension direction of the carbon fiber strip 5 is the same as that of the flexible FBG3, and the moisture-sensitive metal balance spring 2 is arranged on the side of the carbon fiber strip 5 which is suspended relative to the base 1.
The outside cover of base 1 is equipped with dirt proof boot 6, dirt proof boot 6 is used for realizing that humidity sensitive metal balance spring 2 and flexible FBG3 prevent dust. The both ends of base 1 are equipped with the through-hole that is used for optic fibre to pass through, flexible FBG3 establishes ties in optic fibre, the one end of optic fibre is used for connecting the distal end light source, and the other end is used for connecting laser signal processing equipment.
The moving direction of the movable end in the moisture-sensitive metal balance spring 2 is the same as the tangential direction of the movable end.
Specifically, the humidity-sensitive metal balance spring 2 is a balance spring of a mechanical hygrometer used in the market, and the humidity change causes the humidity-sensitive metal balance spring 2 to drive the pointer angle to change. The utility model discloses in adopt this kind of humidity sensitive metal balance spring 2, assume that the environment humidity value is RH, and the tangential force that humidity sensitive metal balance spring 2 produced is F, the unit stress of humidity sensitive metal balance spring 2 humidity change. The moisture-sensitive metal balance spring 2 is composed of beryllium-copper film and moisture-sensitive paper, and the elastic modulus of the metal beryllium-copper is E3Film thickness is h2Beryllium copper width b of the moisture-sensitive metal balance spring 22Wound into an Archimedes spiral with an inner diameter of 2r1Outer diameter of 2r2The number of turns is n. the inner diameter drives the hand to rotate α at full range.
Then
Let K be as follows:
the length, the width and the thickness of the carbon fiber strip 5 subjected to traction are respectively l1B, h; the elastic modulus of the carbon fiber is E1(ii) a The radius of the optical fiber is r, and the fixed length attached to the carbon fiber strip 5 is l2The elastic modulus of the optical fiber is E2；
The force F of the carbon fiber strip 51Is subjected to strain1As follows
The stress of the optical fiber is F2The fiber grating is strained2The length of the two fixed points of the fiber grating is l2；
Then can be obtained according to the mechanical balance
F·l1＝F1·l1+F2·l2
And the strain of the optical fiber and the strain of the carbon fiber should be the same1＝2As a result
Therefore, the humidity RH and the strain show a linear relationship as follows
The unit strain of the fiber grating is related to the return wavelength value lambda of the fiber grating and the drift quantity delta lambda thereof, and the elastic coefficient of the fiber is p, then
The linear relationship between the wavelength drift DeltaLambda measured by the fiber grating system and the humidity value is shown as the following formula
An example of the application is provided by specific data for a moisture sensitive metal balance spring 2 of 12mm external diameter, 2mm internal diameter, 4 turns, 0.05mm metal beryllium copper film thickness, 2mm width and 1.31 × 10 metal beryllium copper modulus of elasticity11N/m2The variation of the full scale pointer is 3 pi/2. Can be calculated
The K value is 0.133N/100%.
The carbon fiber strips 5 had a length of 50mm, a width of 3mm, a thickness of 0.1mm and an elastic modulus of 1.7 × 1011N/m2The whole is a cantilever beam stressed structure, so the force F borne by the carbon fiber strip 51The microstrain relationship generated by it is as followsThe following:
the fixed length of the fiber grating is 30mm, the diameter is 0.125mm, and the elastic modulus is 0.7 × 1011N/m2And thus the force F experienced by the fiber grating2The strain produced is related to the following:
the fiber grating adopts a grating with the center wavelength of 1550nm, the Poisson ratio of the fiber grating is 0.2, and the elasto-optical coefficient p11＝0.121,p12When the effective refractive index is 0.27 and 1.457, the effective elasto-optic coefficient is:
the wavelength drift of the fiber grating is
Δλ＝(1-p)·λ＝0.00127nm/μ
The humidity value RH and the dependent variable show a linear relationship as follows
The linear slope was 0.68%/pm.
Example 2
As shown in fig. 1, the present embodiment provides a temperature and humidity FBG probe, which comprises the humidity FBG probe of embodiment 1, and further comprises a temperature compensation FBG4, wherein the temperature compensation FBG4 is supported by the base 1, and the temperature compensation FBG4 can generate deformation along the extending direction of the temperature compensation FBG4 when the temperature changes, so as to change the laser wavelength passing through the temperature compensation FBG 4; the temperature compensated FBG4 is in series with the flexural FBG3 in the same fiber.
The relative position of the temperature compensated FBG4 to the base 1 is set as: the temperature compensated FBG4 does not affect the deformation of the moisture sensitive metal balance spring 2 and the carbon fiber strip 5. The base 1 is provided with a groove, and the temperature compensation FBG4 is arranged in the groove.
The manufacturing process comprises the following steps:
1) place on the carbon fiber strip after exerting certain pulling force earlier warping FBG (3), heat warping FBG and carbon fiber strip together through the heating plate, glue 343ND on warping FBG both ends point, make its heating solidification. The tension can be measured by a fiber grating demodulator, and the central wavelength of the flexible FBG is shifted by about 0.5nm by the tension. The glue is dispensed for a fixed distance of 30mm and the fiber grating is not to be glued.
2) And after the thermocuring is finished, the flexible FBG and the carbon fiber strip are taken down from the hot plate and fixed on the base, so that the length of the carbon fiber strip is 50mm, and the carbon fiber strip is in a cantilever state.
3) The temperature FBG was fixed in the groove of the base by gluing it through the spot 353ND and heating it on the hot plate. The temperature FBG is required not to affect the mechanical movement of the moisture sensitive metal balance spring and the carbon fiber strip.
4) Then the moisture-sensitive metal hairspring is fixed on the base and is closely adjacent to the movement of the carbon fiber strip. The movable end of the humidity-sensitive metal hairspring is connected with the movable end of the carbon fiber strip through the Kevlar soft rope. The center of the humidity-sensitive metal hairspring is fixed on the base, and the external movable end is connected with the Kevlar rope.
5) The parameters of the moisture-sensitive metal balance spring, the FBG and the carbon fiber strip are shown in the design of the above embodiment.
6) The dustproof cover is arranged on the device, and mainly prevents the moisture-sensitive metal hairspring from being polluted by dust to change the effect.
7) Two FBG fibers in the device are led out, and then the FBG is demodulated by a fiber bragg grating demodulator.
Example 3
This embodiment provides a temperature and humidity measurement system, has utilized the humiture FBG probe in embodiment 2, the one end of optic fibre is connected with laser generating device, and the other end is connected with laser signal processing equipment, laser signal processing equipment can be according to the change of laser wavelength, reachs the information of base department temperature and humidity.
Although the present invention has been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without inventive work are still within the scope of the present invention.
Claims (10)
1. A humidity FBG probe, characterized by comprising,
a base for enabling support;
the humidity-sensitive metal hairspring is sequentially wound into a coiled ruler shape from inside to outside, one end, positioned on the inner ring, of the humidity-sensitive metal hairspring is fixed with the base, the end, positioned on the outer ring, of the humidity-sensitive metal hairspring is a movable end, and the humidity-sensitive metal hairspring has different stresses under different humidity so as to deform the humidity-sensitive metal hairspring along the winding direction;
one end of the carbon fiber strip is fixed with the base, the other end of the carbon fiber strip is suspended relative to the base, a flexible FBG is fixedly arranged on the carbon fiber strip, and the flexible FBG can synchronously deform along with the carbon fiber strip;
the expansion end of the moisture-sensitive metal balance spring is connected with one end of the carbon fiber strip in a suspension mode, so that the moisture-sensitive metal balance spring can transmit deformation generated by self due to humidity change to the carbon fiber strip, the flexible FBG can be synchronously deformed along with the carbon fiber strip, and the wavelength of laser in the flexible FBG is changed and input.
2. The humidity FBG probe according to claim 1, characterized in that the areas of the flexible FBG without gratings at both ends are connection sections for connecting carbon fiber strips.
3. Humidity FBG probe according to claim 1, characterized in that the carbon fiber strip extends in the same direction as the flexible FBG, the humidity sensitive metal balance spring being arranged on the side of the carbon fiber strip which is suspended with respect to the base.
4. The humidity FBG probe according to claim 1, characterized in that the outer sleeve of the base is provided with a dust boot for dust prevention of the humidity sensitive metal balance spring and the flexible FBG.
5. The humidity FBG probe according to claim 1, wherein the base is provided with through holes at both ends for passing optical fibers, the flexible FBG is connected in series in the optical fibers, one end of the optical fibers is used for connecting a remote light source, and the other end of the optical fibers is used for connecting a laser signal processing device.
6. The humidity FBG probe according to claim 1, characterized in that the direction of movement of the active end in the moisture sensitive metal balance spring is the same as the tangential direction at the active end.
7. A temperature and humidity FBG probe, comprising the humidity FBG probe as claimed in any one of claims 1 to 6, further comprising a temperature compensated FBG, the temperature compensated FBG being supported by the base, the temperature compensated FBG being capable of generating a deformation along the direction of extension of the temperature compensated FBG upon a temperature change to change the laser wavelength passing through the temperature compensated FBG;
the temperature compensation FBG and the flexible FBG are connected in series in the same optical fiber.
8. The humiture FBG probe of claim 7, wherein the relative positions of the temperature compensated FBG and the base are set as follows: the temperature compensation FBG does not influence the deformation of the humidity-sensitive metal hairspring and the carbon fiber strip.
9. The humiture FBG probe of claim 7, wherein the base is provided with a groove, and the temperature compensated FBG is arranged in the groove.
10. A temperature and humidity measurement system utilizes the temperature and humidity FBG probe as claimed in any one of claims 7 to 9, wherein one end of the optical fiber is connected with a laser generating device, and the other end of the optical fiber is connected with a laser signal processing device, and the laser signal processing device can obtain the information of the temperature and the humidity at the base according to the change of the laser wavelength.
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| CN202020183483.4U CN211085513U (en) | 2020-02-18 | 2020-02-18 | Humidity FBG probe, temperature and humidity FBG probe and measurement system |
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| CN202020183483.4U CN211085513U (en) | 2020-02-18 | 2020-02-18 | Humidity FBG probe, temperature and humidity FBG probe and measurement system |
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