CN207636149U - A kind of liquid level sensor of modified double optical fiber grating encapsulation - Google Patents
A kind of liquid level sensor of modified double optical fiber grating encapsulation Download PDFInfo
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- CN207636149U CN207636149U CN201721805961.5U CN201721805961U CN207636149U CN 207636149 U CN207636149 U CN 207636149U CN 201721805961 U CN201721805961 U CN 201721805961U CN 207636149 U CN207636149 U CN 207636149U
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Abstract
The utility model discloses a kind of liquid level sensors of modified double optical fiber grating encapsulation, including：Double storehouse metal structure framves, double storehouse metal structure framves are internally provided with spaced walls, and double storehouse metal structure framves are divided into Pressure chamber and temperature storehouse by spaced walls；The one end of Pressure chamber far from spaced walls is equipped with metallic membrane, and pressure fiber grating is equipped in Pressure chamber, temperature compensation optical fiber grating is equipped in temperature storehouse；One end of pressure fiber grating connects metallic membrane, and the other end is by pre-stretching across spaced walls and the welding of temperature compensation optical fiber grating one end；The temperature compensation optical fiber grating other end passes through double storehouses metal structure frame to be connect with signal pickup assembly.The utility model advantageous effect：Temperature grating is only sensitive to the temperature of environment in appropriate free state, and temperature grating, which is in stress grating in same temperature field, plays the role of Liquid level compensator, effectively improves measurement accuracy.
Description
Technical field
The utility model belongs to fibre optical sensor preparing technical field, and the encapsulation especially band temperature for being related to fiber grating is mended
The offset-type grating packaged type repaid.
Background technology
Fiber grating due to small, corrosion-resistant, electromagnetism interference, be easy to networking multiplexing the features such as, in sensor field
Increasingly paid attention to.In water-depth measurement field, fiber bragg grating pressure sensor is with a wide range of applications, but due to naked grating
Pressure coefficient be only 3pm/MPa, so low pressure coefficient cannot meet the general measure requirement in practical application.Another party
Face, fiber grating pair strain and temperature are sensitive simultaneously, and cross sensitivity problem is easily caused in sensing process.Therefore, in order to reach
To the target of pressure measurement, pressure enhanced sensitivity need to be carried out to fiber grating, while also to carry out temperature-compensating.
Traditional pressure sensor generally uses double grating form, but there is no effectively solve temperature although configurations
The cross sensitivity problem of degree, this is because sensor is in the environment of a temperature real-time change, temperature-compensating grating is to temperature
The response speed of degree is less than presser sensor grating, leads to not obtain accurate real time water level information.
Utility model content
In order to solve traditional fiber grating pressure sensor in background technology can not real―time precision measurment liquid level depth lack
Point, the utility model discloses a kind of liquid level sensors of modified double optical fiber grating encapsulation, select linear response hydraulic pressure first
The flexible sheet of variation enables to be bonded in the wavelength change linear response variation in water pressure of the pressure grating on diaphragm.Then pressure
Grating is in temperature grating in identical temperature field, ensures two gratings to the same response of temperature.And use consistent ring
Oxygen resin glue encapsulates, and eliminates because different materials lead to the different influences to grating of temperature expansion coefficient.It is first passed through when measurement pair
The calibration of the calibration and temperature grating initial temperature wavelength of pressure grating initial wavelength, when calculating, disappear from the wavelength data of reading
Influence except temperature change to pressure grating wavelength, by the conversion of wavelength and hydraulic pressure to accurately obtain the letter of liquid level depth
Breath.Effectively solve the disadvantage that traditional fiber grating pressure sensor is unable to real―time precision measurment liquid level depth.
To achieve the goals above, the utility model adopts the following technical solution：
A kind of liquid level sensor of modified double optical fiber grating encapsulation, including：Double storehouse metal structure framves, double storehouse metals
Structure-steel framing is internally provided with spaced walls, and double storehouse metal structure framves are divided into Pressure chamber and temperature storehouse by the spaced walls；The Pressure chamber
One end far from spaced walls is equipped with metallic membrane, and pressure fiber grating is equipped in the Pressure chamber, temperature is equipped in the temperature storehouse
Spend compensated optical fiber grating；One end of the pressure fiber grating connects metallic membrane, and the other end is by pre-stretching across spaced walls
With the welding of temperature compensation optical fiber grating one end；The temperature compensation optical fiber grating other end passes through double storehouse metal structure framves and signal
Harvester connects.
Further, the metallic membrane is tightly fastened to form periphery clamping by laser welding with double storehouses metal structure frame
Structure, the metallic membrane center weld to form central hard-core with metal capillary, and one end of the pressure fiber grating is fixed
On the central hard-core.
Further, the pressure fiber grating and temperature compensation optical fiber grating are existed after divesting coat by fused fiber splice
Together.
Further, the spaced walls are equipped with the first fluting capillary, and the pressure fiber grating passes through the first fluting
Capillary is connect with double storehouses metal structure frame.
Further, the temperature compensation optical fiber grating is connect by the second fluting capillary with double storehouses metal structure frame.
Further, further include：Outer barrel, the outer barrel are connected with double storehouses metal structure frame by thread groove；Outer barrel with it is double
O-ring seal is set between the metal structure frame of storehouse.
The utility model discloses a kind of fiber grating liquid levels to monitor system, including：The above-mentioned any modified of right
Liquid level sensor, wavelength demodulation device and the host computer demodulating system of double optical fiber grating encapsulation；
The liquid level sensor, wavelength demodulation device and host computer demodulating system are sequentially connected.
The utility model advantageous effect：
1. metal flat diaphragm is the change of stress grating wavelength to hydraulic pressure linear response, and by the variation linear transfor of pressure
Change；
2. temperature grating is in, appropriate free state is only sensitive to the temperature of environment, and temperature grating is in same with stress grating
Play the role of Liquid level compensator in one temperature field, effectively improves measurement accuracy；
3. metal structure frame is connected with outer barrel by thread groove in liquid level gauge, O-shaped sealing is placed between interior metal frame and outer barrel
Circle has good sealing performance；
4. the naked fibre drawn from grating one end is by the protection of Loose tube and slotted metal capillary, and again by armouring conduct
External protection is fixed, and the mechanical performance of liquid level gauge entirety is promoted, and is readily adapted for complicated construction environment.
5. host computer demodulating system demarcates the initial wavelength of liquid level sensor and underwater initial temperature, in calculating
The cross sensitivity problem for eliminating temperature, keeps the liquid level information of acquisition accurate in real time.
Description of the drawings
Fig. 1 is fiber grating liquid level monitoring system structure diagram；
Fig. 2 is the encapsulating structure schematic diagram of double grating in internal structure frame；
Fig. 3 (a) is the clamping piece structure schematic diagram that grating connect clamp with armoured cable；
Fig. 3 (b) is the base construction schematic diagram that grating connect clamp with armoured cable；
Fig. 4 is the overall structure diagram of liquid level gauge after the completion of assembly；
Wherein, 1 metallic membrane, 2 metal capillaries, 3 pressure fiber gratings, 4 temperature compensation optical fiber gratings, 5 first flutings
Capillary, 6 second fluting capillaries, 7 pairs of storehouse metal structure framves, 8 fixtures, 9 heat-curable glues, 10 bronze medals sieve, 11 standard Glan connectors,
12 armoured cables, 13O types sealing ring, 14 outer barrels.
Specific implementation mode
The utility model is further described with specific implementation mode below in conjunction with the accompanying drawings.
The utility model discloses the level monitoring systems of complete set fiber grating liquid level meter, as shown in Figure 1, including：
Wavelength demodulation device (including laser), Fiber Grating Liquid Depth Sensor and host computer demodulating system.
Wavelength demodulation device provides light source for sensor and acquires the liquid level signal that sensor obtains.
Host computer demodulating system is calculated by the data to acquisition, is restored liquid level information and is shown.
Key of the fiber-optic grating sensor part as entire monitoring system, the metal flat diaphragm for selecting amount of deflection smaller first
Pressure fiber grating 3 is permanently fixed with diaphragm in the 1 small hard-core part in center of metallic membrane, makes by the variation of direct feeling hydraulic pressure
Variation in water pressure equal proportion is conducted in pressure fiber grating 3.And temperature compensation optical fiber grating 4 is not influenced by pressure conduction, and
And be in same temperature field with pressure fiber grating 3, realize in pressure fiber grating 3 because the sensitive generation strain of temperature disappears
It removes.
The utility model proposes a kind of liquid level sensors of modified double optical fiber grating encapsulation, as shown in Fig. 2, including：
Double storehouse metal structure framves 7, double storehouse metal structure framves 7 are internally provided with spaced walls, and double storehouse metal structure framves 7 are divided into pressure by spaced walls
Storehouse and temperature storehouse；The one end of Pressure chamber far from spaced walls is equipped with metallic membrane 1, and pressure fiber grating 3, temperature are equipped in Pressure chamber
Temperature compensation optical fiber grating 4 is equipped in storehouse；One end of pressure fiber grating 3 connects metallic membrane 1, and the other end is worn by pre-stretching
Super-interval wall and 4 one end welding of temperature compensation optical fiber grating；4 other end of temperature compensation optical fiber grating passes through double storehouses metal structure frame
7 connect with signal pickup assembly.
Metallic membrane 1 is tightly fastened to form periphery clamping structure by laser welding and double storehouses metal structure frame 7, in diaphragm
Centre forms central hard-core with the welding of metal capillary 2；After pressure fiber grating 3 and temperature compensation optical fiber grating 4 divest coat
By fused fiber splice together and be each passed through the first fluting capillary 5, second fluting capillary 6, by filler be bonded be connected；
The first fluting fluting capillary 6 of capillary 5 and second is at double 7 slotting positions of storehouse metal structure frame by filling heat-curable glue 9
The entire internal structure of liquid level gauge is set to constitute an entirety；Grating tail optical fiber is protected and is fixed on double storehouse gold by fixture 8 and armoured cable 12
Belong on structure-steel framing 7；Shown in 8 structure of fixture such as Fig. 3 (a) and Fig. 3 (b).Outer barrel 14 and double storehouses metal structure frame 7 are held in the mouth by thread groove
It connects, embeds waterproof grommet；Armoured cable 12 is closely connect with outer barrel 14 by standard Glan connector 11, and there is waterproof sealing
Property.
The pressure fiber grating 3 being connected with metallic membrane 1 by metal capillary 2 in the utility model is defined as stress light
Grid, it at the second 6 position of fluting capillary after pre-stretching with metal structure frame by connecting；Temperature compensation optical fiber grating 4 is fixed
Justice is temperature compensation grating, it is not acted on by pre-stretching and keeps appropriate free state, and metal knot is fixed on by the first fluting capillary 5
Framework top.When hydraulic pressure acts on metallic membrane 1, the deformation linear conduction that metallic membrane 1 generates causes to answer in stress grating
The wavelength of power grating drifts about, and drift value is linear with hydraulic pressure, and temperature compensation grating is in appropriate free state only to temperature
Variation is sensitive.Since stress grating and temperature compensation grating are in same temperature field, double grating is consistent to the sensitive variation of temperature, because
This temperature compensation grating can be used for offsetting stress grating to the variable quantity of temperature to the variable quantity of temperature, make the wave length shift of stress grating
The result of the only surplus hydraulic pressure effect of amount.The structure design solves the Temperature cross-over tender subject of stress grating, makes stress grating wave
Long variable quantity linearly reflects that the variation of water outlet pressure obtains liquid level information to accurate in real time.
There is real-time accuracy and permanent stability using the fiber grating liquid level meter that the utility model makes.In the structure
Heat-curable epoxy resin glue sticking is used between grating and metal structure, glue after adding silica flour by making grating and intermetallic heat
The coefficient of expansion is close.Metallic membrane 1 is closely welded with double storehouses metal structure frame 7 by laser, and entire internal structure forms one
It is effective whole.On the other hand double storehouse metal structure framves 7 as shown in Figure 2 are closely connected by screw thread with liquid level gauge outer barrel 14,
Add O-ring seal 13 between double storehouse metal structure framves 7 and outer barrel 14, the sealing performance of liquid level gauge is effectively ensured.Make on the whole
Raster liquid level sensor is in permanent steady-working state.Entire assembling process is simple and quick and cost is relatively low, and it is raw to be easy to batch
Production.
In order to liquid level information that this Fiber Grating Liquid Depth Sensor is obtained accurately calculate and the results show that according to
The wavelength information of (FBG) demodulator acquisition develops host computer demodulating system, and concrete implementation mode is as follows：
1) system is demarcated first before sensor is put under water, is principally obtaining the primary wave long number of stress grating
According to λ0。
2) sensor is stood to 5min into the water, reads mark of the wavelength of temperature grating as initial temperature grating wavelength
Determine λT0。
3) it is calculated as follows after obtaining the wavelength of double grating：
H=((λ-λ0)-(λT-λT0)*KT)/K
Wherein, wavelength X and λTThe real-time wavelength obtained after being immersed in the water for sensor, KTIt is to be handed over to eliminate grating temperature
The sensitive compensation factor influenced of fork, the coefficient are obtained by doing temperature sensitive experiment to sensor.K is hydraulic pressure sensitivity coefficient,
It is obtained by the hydraulic pressure sensitive experiment of liquid level sensor.It can be seen that the technical solution eliminates temperature drift pair well from formula
The real-time accurate monitoring to liquid level is realized in the influence of liquid level.
Metallic membrane 1 is small deflection flat diaphragm or convoluted diaphragm, and material is beryllium copper, Stainless steel 316 L or other performance phases
Similar elastic alloy material；Metal capillary 2 isStandard component；Pressure fiber grating 3 and temperature compensation optical fiber grating
4 be Bragg grating；Double 7 materials of storehouse metal structure frame are brass or stainless steel；Heat-curable glue 9 is epoxy resin 353ND；Mark
Quasi- 11 material of Glan connector is stainless steel；The material of outer barrel 14 is stainless steel.
Entire manufacturing process includes the following steps：
1) by the metal capillary of 15mm long 2 with metallic membrane 1 by being laser welded.Metallic membrane 1 and Shuan Cang
Metal structure frame 7 is by being laser welded.
2) two Bragg gratings are chosen, pass through the mutual welding of heat sealing machine one after the side close to grid region divests coat
Body, welding section length 20mm.
3) it is stayed in the other side of stress grating and divests coat at 40mm, and pass through epoxide-resin glue 353ND and metal kernel
Tubule 2 bonds together；It is bonded together by 353ND and the second fluting capillary 6 in the welding area of double grating；In temperature compensation light
The other end naked fibre of grid puts on Loose tube 20cm, will be close to grid region one end naked fibre reserved part divest coat after pass through
353ND bonds together with the first fluting capillary 5 (40mm), is put into 85 degree of insulating boxs together and takes out after cured.
4) pre-stretching of stress grating.Double storehouse metal structure framves 7 are fixed on optical bench adjusting bracket, the first fluting hair
Tubule 5 is for being clamped；Moving horizontally optical adjusting frame makes stress grating be stretched, and the length of stretching and the range of liquid level have
It closes；After process to be tensioned, the first fluting capillary 5 is fixed with fixture 8--.Double storehouses metal structure frame 7 is taken out first
353ND glue of the filling with silica flour, is then placed in 85 DEG C of insulating boxs, is taken out after adhesive curing at the position of fluting capillary 5.
5) unclamp fluting capillary at fixture 8, its in double storehouse metal structure framves 7 junction fill 353ND glue,
85 DEG C of insulating boxs are put into, are taken out after adhesive curing.
6) connection of grating and armoured cable 12.One core of tail optical fiber and armoured cable 12 with Loose tube is passed through into fused fiber splice
Machine links together, and stretches armouring part to the top of double storehouse metal structure framves 7 of mobile cable.Use fixture 88-armoured cable again
12 are screwed together with double storehouses metal structure frame 7.
7) it assembles.Copper sieve 10 is screwed with 14 bottom of outer barrel, silt is avoided to contact diaphragm；Armoured cable will be carried
12 double storehouse metal structure framves 7 are screwed with outer barrel 14 by thread groove, and metal structure frame pedestal embeds O-ring seal 13, plays
The effect of waterproof sealing.Armoured cable 12 is closely coupled with outer barrel 14 by standard Glan connector 11, ensures the waterproof of whole device
Sealing performance.So far the entire manufacturing process of liquid level sensor is completed.
It is above-mentioned although specific embodiments of the present invention are described with reference to the accompanying drawings, but not to this practicality newly
The limitation of type protection domain, those skilled in the art should understand that, based on the technical solution of the present invention, ability
Field technique personnel need not make the creative labor the various modifications or changes that can be made still in the protection model of the utility model
Within enclosing.
Claims (7)
1. a kind of liquid level sensor of modified double optical fiber grating encapsulation, which is characterized in that including：Double storehouse metal structure framves, institute
It states double storehouses metal structure frame and is internally provided with spaced walls, double storehouse metal structure framves are divided into Pressure chamber and temperature storehouse by the spaced walls；
The one end of the Pressure chamber far from spaced walls is equipped with metallic membrane, and pressure fiber grating, the temperature are equipped in the Pressure chamber
Temperature compensation optical fiber grating is equipped in storehouse；One end of the pressure fiber grating connects metallic membrane, and the other end is by pre-stretching
Across spaced walls and the welding of temperature compensation optical fiber grating one end；The temperature compensation optical fiber grating other end passes through double storehouses metal knot
Framework is connect with signal pickup assembly.
2. a kind of liquid level sensor of modified double optical fiber grating encapsulation as described in claim 1, which is characterized in that the gold
Belong to diaphragm to be tightly fastened to form periphery clamping structure by laser welding and double storehouses metal structure framves, the metallic membrane center with
Metal capillary welds to form central hard-core, and one end of the pressure fiber grating is fixed on the central hard-core.
3. a kind of liquid level sensor of modified double optical fiber grating encapsulation as described in claim 1, which is characterized in that the pressure
Power fiber grating divest coat with temperature compensation optical fiber grating after by together with fused fiber splice.
4. a kind of liquid level sensor of modified double optical fiber grating encapsulation as described in claim 1, which is characterized in that between described
Next door is equipped with the first fluting capillary, and the pressure fiber grating is connected by the first fluting capillary and double storehouses metal structure frame
It connects.
5. a kind of liquid level sensor of modified double optical fiber grating encapsulation as described in claim 1, which is characterized in that the temperature
Degree compensated optical fiber grating is connect by the second fluting capillary with double storehouses metal structure frame.
6. a kind of liquid level sensor of modified double optical fiber grating encapsulation as described in claim 1, which is characterized in that also wrap
It includes：Outer barrel, the outer barrel are connected with double storehouses metal structure frame by thread groove；O is set between outer barrel and double storehouse metal structure framves
Type sealing ring.
7. a kind of fiber grating liquid level monitors system, which is characterized in that including：Any modified described in claim 1-6
Liquid level sensor, wavelength demodulation device and the host computer demodulating system of double optical fiber grating encapsulation；
The liquid level sensor, wavelength demodulation device and host computer demodulating system are sequentially connected.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107941306A (en) * | 2017-12-21 | 2018-04-20 | 珠海任驰光电科技有限公司 | A kind of liquid level sensor and level measuring method of the encapsulation of modified double optical fiber grating |
-
2017
- 2017-12-21 CN CN201721805961.5U patent/CN207636149U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107941306A (en) * | 2017-12-21 | 2018-04-20 | 珠海任驰光电科技有限公司 | A kind of liquid level sensor and level measuring method of the encapsulation of modified double optical fiber grating |
| CN107941306B (en) * | 2017-12-21 | 2023-09-05 | 珠海任驰光电科技有限公司 | Improved double-fiber grating packaged liquid level sensor and liquid level measurement method |
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