Summary of the invention
The purpose of this utility model is exactly the defects that will overcome prior art, the composite liquid optical fiber concentration meter of a kind of fibre-optical probe and this fibre-optical probe of employing is provided, its error is little, reliability is high, be not subjected to the impact of electromagnetic field, large electric current and high temperature, probe size is little, and easily installation and maintenance can realize Distance Test.
For reaching above-mentioned purpose, the fibre-optical probe that the utility model provides comprises measuring staff, the front end of described measuring staff is equipped with Fibre Optical Sensor, guiding fiber bundle, fiber distribution box are installed in the inner chamber of described measuring staff, have single-core fiber bundle, detector and the light source of protective sleeve, described Fibre Optical Sensor comprises input optical fibre, output optical fibre and 45° angle prism, described 45° angle prism is positioned at the outside of described measuring staff, inserts in the fluid to be measured 20; Described input optical fibre links to each other with described light source, described output optical fibre links to each other with described detector through described guiding fiber bundle, fiber distribution box, single-core fiber bundle with protective sleeve successively, described input optical fibre imports light into described 45° angle prism, and the refract light that described output optical fibre is accepted from described 45° angle prism is measured electric signal through described detector output; Described Fibre Optical Sensor is 2, comprise concentration sensor and temperature sensor, described detector comprises concentration detector and hygrosensor, described light source comprises LASER Light Source and led light source, described LASER Light Source is used for described concentration sensor, described led light source is used for described temperature sensor, and the output optical fibre of described hygrosensor receives end face and is provided with the ASGA semiconductor material layer.
The utility model fibre-optical probe, wherein said LASER Light Source is connected with the first bright detecting device through optical fiber, described led light source is connected with the second bright detecting device through another optical fiber, and the described first bright detecting device and the second bright detecting device are exported respectively bright detection signal separately.
The utility model fibre-optical probe, wherein said LASER Light Source adopts semiconductor laser, and its wavelength is 650nm, and described Laser Power Devices are provided with the luminous energy control circuit, and the wavelength of described led light source is 910nm.
The utility model fibre-optical probe, wherein said detector adopts silicon photocell.
The utility model fibre-optical probe, wherein in described concentration sensor, described 45° angle prism replaces with circular arc optical fiber, described circular arc optical fiber is positioned at the outside of described measuring staff, insert in the fluid to be measured, input optical fibre imports light into described circular arc optical fiber, and the reflected light that output optical fibre is accepted from described circular arc optical fiber is measured electric signal through described concentration detector output.
The utility model fibre-optical probe, wherein in described concentration sensor, described 45° angle prism replaces with bare fibre, described bare fibre is positioned at the outside of described measuring staff, insert in the fluid to be measured, input optical fibre imports light into described bare fibre, and the light that output optical fibre is accepted from described bare fibre is measured electric signal through described concentration detector output.
For reaching above-mentioned purpose, the composite liquid optical fiber concentration meter of the described fibre-optical probe of employing that the utility model provides, also comprise the test macro that links to each other with this fibre-optical probe, described test macro comprises the first amplifier that links to each other with described concentration detector and the second amplifier that links to each other with described hygrosensor, the the first bright detecting device that links to each other with described LASER Light Source and the second bright detecting device that links to each other with described led light source, an and dsp processor, described the first amplifier, the second amplifier, the output signal of the first bright detecting device and the second bright detecting device is connected to respectively described dsp processor, and described dsp processor is connected with display and output port.
The composite liquid optical fiber concentration meter that the utility model provides, wherein said the first amplifier is connected with the first sensitivity controller and first zero regulator, and described the second amplifier is connected with the second sensitivity controller and the second zero adjuster.
The advantage of the composite liquid optical fiber concentration meter of the utility model fibre-optical probe and this fibre-optical probe of employing is: because optical fiber is to be made by glass or plastics, thereby be not afraid of the corrosion of liquid or gas.Probe size is little, and because optical fiber is flexible, very little to the flow resistance of fluid to be measured or gas, and Optical Fiber Transmission is not subjected to the impact of electromagnetic field, large electric current and high temperature, therefore safety and good reliability, error is little, installation and maintenance is easy, distribution mustn't special consideration.Because the test side separates with main frame, the test side is directly inserted sample and just can be measured, and does not need special reconstitute device, can be directly brought into technological process production line, realized remote in real time measurement.Therefore, take liquid in the process for making of main various industries, do not need to select special place, in the abominable place of test environment, such as high temperature, high humidity, run into the outdoor of wind and rain and need and can both use in the pipeline of explosion-proof technological process.
Embodiment
The principle of work of fibre optic concentration sensor is as follows:
Light beam incides the second medium (refractive index n 2) from a kind of medium (refractive index n 1), and according to the Snell law, incidence angle θ 1 satisfies following relational expression with refraction angle θ 2
n1Sinθ1=n2Sinθ2----------(1)
The reflection coefficient parallel with vertical with the plane of incidence is by Fresnel formula expression (1)
rp=-tg(θ1-θ2)/tg(θ1+θ2)------------(2)
rs=-Sin(θ1-θ2)/Sin(θ1+θ2)----------(3)
The reflection of light rate is
R=(rp2+rs2)1/2---------(4)
Reflection of light intensity is
IR=rp2Iop+rs2Ios------------(5)
Io=Iop+Ios is incident intensity, and footnote p s represents respectively plane of polarization and parallels with the plane of incidence and vertical component.
For selected optical fiber, its n1 is that definite value, θ 1 also are definite value, when it touches the liquid of different refractivity, by formula (1) formula n2=n1Sin θ 1/ θ 2, for the θ 2 decision what n2 of formula (2) (3).Therefore n2 gets different values, has directly determined the value of IR.Mini optical fibre refractive index concentration sensor utilizes this principle and designs.
Describe the embodiment of the composite liquid optical fiber concentration meter of a kind of fibre-optical probe of the utility model and this fibre-optical probe of employing in detail below in conjunction with accompanying drawing.
With reference to Fig. 1, the fibre-optical probe that the utility model provides is equipped with Fibre Optical Sensor 1 at the front end of measuring staff, guiding fiber bundle 2, fiber distribution box 3 is installed in the inner chamber of measuring staff, has single-core fiber bundle 4, detector and the light source of protective sleeve.In conjunction with reference to Fig. 2 or Fig. 6, Fibre Optical Sensor 1 comprises input optical fibre 31, output optical fibre 33 and 45° angle prism 32, and 45° angle prism 32 is positioned at the outside of measuring staff, and Fibre Optical Sensor length is no more than 50mm, inserts and gathers concentration and temperature signal in the fluid to be measured 20.Input optical fibre 31 links to each other with light source, and output optical fibre 33 links to each other with detector through guiding fiber bundle 2, fiber distribution box 3, single-core fiber bundle 4 with protective sleeve successively.
Input optical fibre 31 imports light into 45° angle prism 32, and the refract light that output optical fibre 33 is accepted by 45° angle prism 32 is measured electric signal through detector output.The length of measuring staff signal hop is decided according to user's needs, and design length is 2 meters, generally is no more than 4 meters.
Because the production scene of chemical combination liquid exists temperature and concentration state variation simultaneously, so, in the embodiment of the fibre-optical probe that the utility model provides, utilize large core diameter silica fibre to consist of the compound sensor of concentration and temperature, two optical fiber form concentration sensor, two optical fiber form temperature sensor, are installed in the same probe.So Fibre Optical Sensor 1 is 2, comprises concentration sensor and temperature sensor, adopt such as Fig. 2 and structure shown in Figure 6 respectively.
Detector comprises concentration detector 5 and hygrosensor 6, and light source comprises LASER Light Source 7 and led light source 8.LASER Light Source 7 is used for concentration sensor, adopts semiconductor laser, and its wavelength is 650nm.Led light source 8 is used for temperature sensor, and wavelength is 910nm.Detector adopts silicon photocell.The output of fiber distribution box 3 is divided into three beams single-core fiber bundle 4; all has the protective casing protection; a branch of single-core fiber bundle 4 links to each other with LASER Light Source 7, and other two bundle single-core fiber bundles 4 are used for linking to each other with 6 two detectors of concentration detector 5 and hygrosensor, and two detectors convert light signal to electric signal.
In the embodiment of the fibre-optical probe that the utility model provides, utilize the 45° angle prism to change the direction of propagation of light, when prism was present in the air (the refractive index n 0=1 of air), light produced total reflection.When prism was present in the different liquid, because its refractive index is different, light will produce refraction, its refract light brightness size and the refractive index of liquid and the proportional relation of concentration of liquid, thus realize the concentration of liquid is measured fast, accurately.With reference to Fig. 6, the output optical fibre 33 of hygrosensor 6 receives end face and is provided with ASGA semiconductor material layer 34.ASGA semiconductor material layer 34 is the material to the temperature variation sensitivity.
In another embodiment of the fibre-optical probe that the utility model provides, with reference to Fig. 3, the 45° angle prism of concentration sensor replaces with circular arc optical fiber 12, and circular arc optical fiber 12 is positioned at the outside of measuring staff, inserts in the fluid to be measured 20.Circular arc optical fiber 12 is abutted against together by two smooth bare fibres of end face processing, through special process end face is processed into a smooth arc surface.Input optical fibre 11 imports light into circular arc optical fiber 12, during light process circular arc optical fiber 12, is divided into reflected light and refract light by its inherent characteristic.Refract light enters fluid to be measured 20, and output optical fibre 13 is accepted reflected light from circular arc optical fiber 12 and measured electric signal through 5 outputs of concentration detector.
In the another embodiment of the fibre-optical probe that the utility model provides, with reference to Fig. 4,450 angle prisms of concentration sensor replace with bare fibre 22, and bare fibre 22 is positioned at the outside of measuring staff, insert in the fluid to be measured 20.Input optical fibre 21 imports light into bare fibre 22, owing to will leak by emergence pattern when bare fibre 22 immerses in the fluid to be measured 20, namely optical fiber and fluid to be measured 20 produce mutually coupling, light characteristic is different because of the light quantity of the different outside scattering of refractive index of liquid, also be that the light loss vector is different, because the optical index of fluid to be measured 20 is higher than air, optical fiber light leakage rate different in liquid and air, the light of transmission will die down, this variable quantity is relevant with the concentration value of liquid, and the light that output optical fibre 23 is accepted from bare fibre 22 is measured electric signal through 5 outputs of concentration detector.
The embodiment of the composite liquid optical fiber concentration meter of this fibre-optical probe of employing that the utility model provides has installed two independently fibre-optical probes of becoming one of Fibre Optical Sensor 1 and consist of test macro.
With reference to Fig. 6, test macro comprises the first amplifier 15 that links to each other with concentration detector 5 and the second amplifier 18 that links to each other with hygrosensor 6, the first bright detecting device 9 that links to each other with LASER Light Source 7 and the second bright detecting device 10 that links to each other with led light source 8, and a dsp processor 19.The output signal of the first amplifier 5, the second amplifier 15, the first bright detecting device 9 and the second bright detecting device 10 is connected to respectively dsp processor 19, and dsp processor 19 is connected with display 26 and output port 27.The first amplifier 5 is connected with the first sensitivity controller 16 and first zero regulator 17, the second amplifiers 15 are connected with the second sensitivity controller 24 and the second zero adjuster 25.Two light signals that concentration detector 5 and hygrosensor 6 are accepted convert electric signal to, are input to respectively dsp processor 19 through the signal of exporting after regulating at amplifier amplification, Adjustment of sensitivity, zero point and carry out the data processing.Dsp processor 19 comprises A/D conversion and DSP data processing module.
Laser Power Devices 7 are provided with luminous energy control circuit 28, with reference to Fig. 7, be the semiconductor laser with luminous energy control, when the luminous power of semiconductor laser improves, be detected device PIN and accept, the light intensity that it is accepted is stronger, then the lower voltage on triode 2SA1015 the electric current of triode 2SC1545 is descended, so the photocurrent of semiconductor laser also descends, the luminous power of semiconductor laser also descends, otherwise same.
In order to improve measuring accuracy, directly from light source, be guided out light beam and carry out the light detection.LASER Light Source 7 is connected with the first bright detecting device 9 through optical fiber, and led light source 8 is connected with the second bright detecting device 10, the first bright detecting devices 9 and the second bright detecting device 10 through another optical fiber and exports respectively separately bright detection signal.With reference to Fig. 8, the first bright detecting device 9 is made of chip circuit TLO72 and AD620, and acceptance is input to dsp processor 19 and carries out the data processing, in order to improve measuring accuracy by the light that light guide bundles returns.For carrying out temperature detection, the second bright detecting device 10 that also has a route TLO72 and AD620 to form.Foregoing circuit is known technology, so be not described further.
The composite liquid optical fiber concentration meter advantage of the utility model fibre-optical probe and this fibre-optical probe of employing is as follows:
1 because the test side of contact liq is fibre-optical probe, and separates between the main frame, thereby can realize Distance Test, carries out the real time measure on the to be directly brought into technological process production line.
2 owing to be optical quantities, so explosion-proof, anti-electromagnetic interference (EMI) is in the abominable place of test environment and need can both use in the explosion-proof technological process.
3 because the test side is directly inserted sample and just can be measured, and does not need special reconstitute device.Probe size is little, and because optical fiber is flexible, does not need to select special place, and height is installed easily.
4 Optical Fiber Transmission are not subjected to the impact of electromagnetic field, large electric current and high temperature, so distribution mustn't special consideration, and safe reliability is high.
Embodiment recited above is described preferred implementation of the present utility model, is not that design of the present utility model and scope are limited.Under the prerequisite that does not break away from the utility model design concept; various modification and improvement that this area ordinary person makes the technical solution of the utility model; all should drop into protection domain of the present utility model; the technology contents that the utility model is asked for protection all is documented in claims.