Method and device for detecting humidity of tail gas of fabric setting machine

文档序号：1919758 发布日期：2021-12-03 浏览：31次中文

阅读说明：本技术 一种织物定形机尾气湿度检测方法及装置 (Method and device for detecting humidity of tail gas of fabric setting machine ) 是由申雪韵张建新刘岳李消晋于 2021-07-21 设计创作，主要内容包括：本发明提供的一种针织物定形机尾气湿度检测装置及方法,包括：将改性的含氟聚酰亚胺涂覆到光纤Bragg光栅栅区,制成湿度传感器；使用饱和盐溶液湿度标定法对湿度传感器进行标定,将光纤Bragg光栅中心波长值与湿度值对应；对光纤Bragg光栅湿度传感器进行温度补偿,通过分段标定方法得到温度补偿系数,得出传感器中心波长变化量与外界环境温度变化量之间的关系；通过线性插值法得出温度变化造成的光纤Bragg光栅中心波长漂移量并对光纤Bragg光栅中心波长进行补偿并对湿度进行反演计算；解决了现有技术中基于二氧化锆作传感探头需要定期更换,维护难度大且成本高,采用光纤Bragg光栅湿度传感器又有温湿度交叉敏感的问题。(The invention provides a device and a method for detecting tail gas humidity of a knitted fabric setting machine, comprising the following steps: coating the modified fluorine-containing polyimide on a fiber Bragg grating area to prepare a humidity sensor; calibrating the humidity sensor by using a saturated saline solution humidity calibration method, and enabling the central wavelength value of the optical fiber Bragg grating to correspond to the humidity value; carrying out temperature compensation on the optical fiber Bragg grating humidity sensor, and obtaining a temperature compensation coefficient by a sectional calibration method to obtain the relation between the variation of the central wavelength of the sensor and the variation of the external environment temperature; obtaining the fiber Bragg grating central wavelength drift amount caused by temperature change through a linear interpolation method, compensating the fiber Bragg grating central wavelength and performing inversion calculation on humidity; the problem of among the prior art need regularly change based on zirconium dioxide as sensing probe, maintain the degree of difficulty big and with high costs, adopt optic fibre Bragg grating humidity transducer again have temperature and humidity cross sensitive is solved.)

1. A method of detecting moisture in exhaust from a fabric setting machine, the method comprising:

coating the modified fluorine-containing polyimide on a fiber Bragg grating area to prepare a humidity sensor;

calibrating the humidity sensor by using a saturated saline solution humidity calibration method, and enabling the central wavelength value of the optical fiber Bragg grating to correspond to the humidity value;

carrying out temperature compensation on the optical fiber Bragg grating humidity sensor, and obtaining a temperature compensation coefficient by a sectional calibration method to obtain the relation between the variation of the central wavelength of the sensor and the variation of the external environment temperature;

and obtaining the fiber Bragg grating central wavelength drift caused by temperature change by a linear interpolation method, compensating the fiber Bragg grating central wavelength and performing inversion calculation on humidity.

2. The method of claim 1, wherein the humidity sensor is formed by applying a modified polyimide to the fiber Bragg grating grid area; the preparation method comprises the following steps:

3. The method of claim 1, wherein the reflected light from the fiber Bragg grating moisture sensor is split into two equal intensity beams, one of which is used as a reference beam and the other is used as a measuring beam filtered by the edge filter, and the difference between the two is used to obtain the intensity difference between the measuring beam and the reference beam.

4. The method of claim 1, wherein the moisture content of the exhaust from the fabric setting machine,

the relationship between the variation of the central wavelength of the sensor and the variation of the external environment temperature is as follows:

Δλ＝0.0099ΔT+0.04

wherein, Δ λ represents the variation of the central wavelength of the fiber Bragg grating humidity sensor, and Δ T represents the variation of temperature.

5. The method for detecting the humidity of the tail gas of the fabric setting machine according to claim 4, wherein the temperature compensation coefficient is determined according to the ambient temperature in the setting machine, and the central wavelength of the fiber Bragg grating is compensated, specifically: the temperature is divided into two sections by using a sectional compensation method, and the humidity measurement in the range of 30-70 ℃ is subjected to temperature compensation according to the following rules:

when the temperature range is in the range of 30-40 ℃, performing temperature compensation by taking 30 ℃ as a reference according to the formula:wherein T is more than or equal to 30 DEG c<40°c；

When the temperature range is in the range of 40-50 ℃, the temperature compensation is carried out by taking 40 ℃ as a reference according to the formula:wherein T is more than or equal to 40 DEG c<50°c；

When the temperature range is within 50-60 ℃, performing temperature compensation by taking 50 ℃ as a reference according to the formula:wherein T is more than or equal to 50 DEG c<60°c；

When the temperature range is in the range of 60-70 ℃, performing temperature compensation by taking 60 ℃ as a reference according to the formula:wherein T is more than or equal to 60 DEG c<70°c；

When the temperature is higher than 70 ℃, performing temperature compensation at 70 ℃, according to the formula:wherein, T is less than or equal to 70 ℃, and lambda is in the formula_PRepresenting the predicted value of the center wavelength of the fiber Bragg grating,representing the humidity value.

6. An apparatus for detecting moisture in exhaust gas from a fabric setting machine, the apparatus comprising:

the temperature detection module (1), the signal processing module (2) and the data processing module (3);

the temperature detection module (1) comprises: the ASE broadband optical fiber humidity sensor comprises an ASE broadband light source (1-1), a three-port optical fiber circulator (1-2) and an optical fiber Bragg grating humidity sensor (1-3);

the ASE broadband light source (1-1) is connected with the three-port optical fiber circulator (1-2);

the three-port optical fiber circulator (1-2) is connected with the optical fiber Bragg grating humidity sensor (1-3);

the signal processing module (2) comprises: an edge filter (2-1), a photoelectric conversion circuit (2-2), a linear amplification circuit (2-3), a low-pass filter (2-4) and a dark current compensation circuit (2-5);

the edge filter (2-1) is connected with the three-port optical fiber circulator (1-2);

the edge filter (2-1) is sequentially connected with the photoelectric conversion circuit (2-2), the linear amplification circuit (2-3), the low-pass filter (2-4) and the dark current compensation circuit (2-5);

the data processing module (3) comprising: an upper computer (3-1);

the upper computer (3-1) is connected with the dark current compensation circuit (2-5).

7. The fabric setting machine exhaust gas moisture detection device of claim 6, wherein the ASE broadband light source (1-1) is specifically: and the C-band ASE light source is used for providing near infrared light with constant power for the humidity detection device.

8. The fabric setter tail gas humidity detection device of claim 6, wherein the fiber Bragg grating humidity sensor (1-3) has a fluorine-containing polyimide humidity sensitive coating.

9. The fabric setting machine exhaust gas moisture detection device of claim 6, wherein the photoelectric conversion circuit (2-2) comprises: PIN photodiode and current-voltage conversion circuit.

10. The device for detecting the humidity of the tail gas of the fabric setting machine according to claim 6, wherein the photoelectric conversion circuit (2-2) converts the light intensity of the measuring light into a voltage signal, the voltage signal needs to be amplified by the linear amplification circuit (2-3) and then passes through the low-pass filter (2-4) to be filtered to remove the high-frequency noise interference, finally, the measuring error caused by the dark current of the PIN photodiode is compensated by the dark current compensation circuit (2-5), and the electric signal is transmitted to the data processing module (3) to be A/D sampled.

Technical Field

The invention relates to the field of parameter detection of a setting machine, in particular to a method and a device for detecting the humidity of tail gas of a fabric setting machine.

Background

The fabric setting machine is a device for drying and finishing fabrics by utilizing hot air and setting the fabrics, the requirement on humidity is very high in the drying process, and the humidity is an important factor influencing the fabric setting effect. The exhaust temperature of the knitted fabric setting machine can reach about 90 ℃, and a common resistance type humidity detection device in common life is difficult to work normally in the temperature area, so that the humidity is difficult to detect accurately in the industrial environment.

At present, the drying process is estimated mainly by the experience of skilled workers in industrial production, but the method has strong subjectivity and can also generate the phenomenon of 'over-drying' or 'under-drying' in the actual production process. Not only influences the quality of products, but also causes the waste of resources, increases the cost of enterprises and reduces the economic benefit.

At present, in the aspect of automatic detection, zirconium dioxide is mainly used as a sensing probe of sensing equipment for detecting the tail gas humidity of a knitted fabric setting machine, water molecules in an environment to be detected can be combined with hydrogen ions in an adsorption layer of the zirconium dioxide sensor, when the humidity rises, the current of the adsorption layer of the sensor easily flows, the impedance of the adsorption layer of the sensor is smaller, and the tail gas humidity is calculated according to the change of the impedance. However, the method has certain disadvantages, the zirconium dioxide sensor probe is consumed to a certain extent in the working process, needs to be replaced every three years, is low in detection precision, high in maintenance difficulty and high in maintenance cost, and increases the enterprise cost.

Although the measurement environment temperature of the optical fiber Bragg grating humidity sensor can reach 90 ℃, the optical fiber Bragg grating humidity sensor is sensitive to not only humidity but also temperature, and has the problem of cross sensitivity.

Disclosure of Invention

In order to solve the technical problems, the invention discloses a method and a device for detecting the tail gas humidity of a fabric setting machine, and solves the problems that in the prior art, the subjectivity of manual estimation is strong, the product quality is unstable, a sensing probe based on zirconium dioxide needs to be replaced every three years, the detection precision is low, the maintenance difficulty is high, the maintenance cost is high, and a fiber Bragg grating humidity sensor is adopted to be sensitive to the temperature and the humidity in a crossed manner.

In order to achieve the purpose, the invention provides a method for detecting the humidity of the tail gas of a fabric setting machine, which comprises the following steps:

coating the modified polyimide on a grating region of the fiber Bragg grating to prepare a humidity sensor;

In one embodiment, the polyimide is coated on the grating area of the fiber Bragg grating to form the humidity sensor; the preparation method comprises the following steps:

In one embodiment, the reflected light of the fiber Bragg grating humidity sensor is divided into two paths of light with equal intensity, one path of light is used as a reference beam, the other path of light is used as a measuring beam and is filtered by an edge filter, and the two paths of light are subtracted to obtain the light intensity difference between the measuring beam and the reference beam.

In one embodiment, the relationship between the variation of the center wavelength of the sensor and the variation of the external environment temperature is as follows: Δ λ 0.0099 Δ T +0.04

Wherein, Δ λ represents the variation of the central wavelength of the fiber Bragg grating humidity sensor, and Δ T represents the variation of temperature.

In an embodiment, the determining a temperature compensation coefficient according to an ambient temperature in a setting machine to compensate for a central wavelength of the optical fiber Bragg grating specifically includes: the temperature is divided into two sections by using a sectional compensation method, and the humidity measurement in the range of 30-70 ℃ is subjected to temperature compensation according to the following rules:

When the temperature range is within 50-60 ℃, performing temperature compensation by taking 50 ℃ as a reference according to the formula:wherein T is more than or equal to 50 DEG c<60°c；

When the temperature is higher than 70 ℃, performing temperature compensation at 70 ℃, according to the formula:wherein, T is less than or equal to 70 ℃, in the formula, lambdap represents the predicted value of the central wavelength of the fiber Bragg grating,representing the humidity value.

The embodiment of the invention also provides a device for detecting the humidity of the tail gas of the fabric setting machine, which comprises:

the temperature detection module 1, the signal processing module 2 and the data processing module 3;

the temperature detection module 1 includes: the system comprises an ASE broadband light source 1-1, a three-port optical fiber circulator 1-2 and an optical fiber Bragg grating humidity sensor 1-3;

the ASE broadband light source 1-1 is electrically connected with the three-port optical fiber circulator 1-2;

the three-port optical fiber circulator 1-2 is in bidirectional electrical connection with the optical fiber Bragg grating humidity sensor 1-3;

the signal processing module 2 includes: an edge filter 2-1, a photoelectric conversion circuit 2-2, a linear amplification circuit 2-3, a low-pass filter 2-4 and a dark current compensation circuit 2-5;

the edge filter 2-1 is electrically connected with the three-port optical fiber circulator 1-2;

the edge filter 2-1 is electrically connected with the photoelectric conversion circuit 2-2, the linear amplification circuit 2-3, the low-pass filter 2-4 and the dark current compensation circuit 2-5 in sequence;

the data processing module 3 includes: an upper computer 3-1;

the upper computer 3-1 is electrically connected with the dark current compensation circuit 2-5.

In one embodiment, the ASE broadband light source 1-1 specifically includes: and the C-band ASE light source is used for providing near infrared light with constant power for the humidity detection device.

In one embodiment, the fiber Bragg grating humidity sensors 1-3 have a fluorine-containing polyimide humidity sensitive coating.

In one embodiment, the photoelectric conversion circuit 2-2 includes: PIN photodiode and current-voltage conversion circuit.

In one embodiment, the photoelectric conversion circuit 2-2 converts the light intensity of the measurement light into a voltage signal, the voltage signal needs to be amplified by the linear amplification circuit 2-3 and then passes through the low-pass filter 2-4 for filtering processing to remove high-frequency noise interference, finally, a dark current compensation circuit (2-5) compensates the measurement error caused by the dark current of the PIN photodiode, and the electric signal is transmitted to the data processing module 3 for a/D sampling.

The embodiment of the invention has the following beneficial effects:

according to the method and the device for detecting the tail gas humidity of the fabric setting machine, the external humidity changes to cause the modified polyimide humidity sensitive film to deform, so that the grid spacing of the optical fiber Bragg grating is changed, the central wavelength of the optical fiber Bragg grating is shifted, the quantity relation between the shift quantity of the central wavelength and the external humidity changes is obtained by establishing a sensing model, an optical signal is converted into a digital signal through a signal processing module and is transmitted into an upper computer, the upper computer performs temperature compensation on the digital signal according to the environmental temperature, the problem of cross sensitivity is solved, the environmental humidity in the setting machine is obtained by humidity inversion calculation, the air exhaust rate of the setting machine can be controlled according to the humidity, the production efficiency is improved, the energy is saved, the emission is reduced, and the product quality is guaranteed.

Drawings

In order to more clearly illustrate the invention described in the present application and disclose a method and a device for detecting humidity of exhaust gas from a fabric setting machine, the drawings required for the embodiments will be briefly described below, it should be apparent that the drawings in the following description are only some embodiments of the invention, and that other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a method for detecting the moisture level of the exhaust gas of a fabric setting machine according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a hardware structure of an exhaust gas humidity detection device of a fabric setting machine according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating the calibration results of the humidity calibration of the fiber Bragg grating humidity sensor according to the embodiment of the present invention;

FIG. 4 is a graph of temperature compensated error analysis of a fiber Bragg grating according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or server that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1, in order to achieve the above object, the present invention provides a method for detecting moisture in tail gas of a fabric setting machine, comprising:

s11, coating the modified polyimide on a fiber Bragg grating area to manufacture a humidity sensor;

s12, calibrating the humidity sensor by using a saturated salt solution humidity calibration method, and enabling the central wavelength value of the optical fiber Bragg grating to correspond to the humidity value;

s13, temperature compensation is carried out on the optical fiber Bragg grating humidity sensor, a temperature compensation coefficient is obtained through a sectional calibration method, and the relation between the variation of the central wavelength of the sensor and the variation of the external environment temperature is obtained;

s14, obtaining the fiber Bragg grating central wavelength drift caused by temperature change through a linear interpolation method, compensating the fiber Bragg grating central wavelength and performing inversion calculation on humidity.

In one illustrative embodiment, the fiber Bragg grating itself is not sensitive to humidity, and a humidity sensitization technology is required to enable the fiber Bragg grating to change along with the change of humidity; at present, there are many materials that can be used to fabricate humidity sensitive films of humidity sensors: for example, there are some materials with strong hydrophilicity such as polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), Polyimide (PI), hydrogel, etc.

The industrial high-temperature environment can reach 90 ℃, the designed humidity sensor has the capacity of normally working in the environment of 90 ℃, and polyimide is used as a humidity sensitive material for manufacturing the humidity sensor.

In one illustrative embodiment, the modified polyimide is coated on the grating region of the fiber Bragg grating to form a humidity sensor; the preparation method comprises the following steps:

firstly, partially immersing a grating region of the optical fiber Bragg grating in a prepared polyimide solution which is dehydrated and cyclized by a chemical method for 10 seconds for many times; then, the immersed and dipped fiber Bragg grating is placed in a flat glass mold, the fiber Bragg grating is required to be flatly placed in a groove of the flat glass mold in the step, and the dipped polyimide solution is required to be carefully confirmed whether bubbles are formed on the surface of a grating area of the fiber Bragg grating or not, if bubbles are formed, the bubbles are required to be picked out, so that the surface of a coating layer is uniform and flat, otherwise, the fiber Bragg grating is deformed in the heating process, and the initial central wavelength of the sensor is influenced; then putting the flat glass mold into a vacuum drying oven for thermosetting molding;

the greater the thickness of the coating, the greater the sensitivity of the fiber grating, but the greater the susceptibility to interference from other external parameters, and therefore in the embodiments of the present description, a coating thickness of between 10 and 15 times is preferred.

In an embodiment of the specification, the reflected light of the fiber Bragg grating humidity sensor is divided into two paths of light with equal intensity, one path of light is used as a reference beam, the other path of light is used as a measuring beam and is filtered by an edge filter, and the two paths of light are subtracted to obtain the light intensity difference between the measuring beam and the reference beam; because the filtering edge is linear, after being filtered by the edge filter, the light intensity and the wavelength are direct proportional functions related to the slope of the filtering edge, and therefore the variation of the central wavelength of the optical fiber Bragg grating can be obtained.

In one illustrative embodiment, the temperature compensation principle of the fiber Bragg grating humidity sensor is as follows:

the temperature and the humidity are in linear relation to the deformation of the grating region of the optical fiber Bragg grating, so that the superposition principle is satisfied. The axial strain ε z can be expressed by the following formula (1-1):

ε φ, ε T in equation (1-1) represents the humidity-induced axial strain and the temperature-induced axial strain, respectively, where ε T can be described by equation (1-2):

wherein α P and α F represent the coefficient of thermal expansion of the humidity sensitive material and the coefficient of thermal expansion of the fiber Bragg grating, respectively.

Therefore, the amount of shift of the center wavelength of the fiber Bragg grating humidity sensor under the simultaneous action of temperature and humidity can be expressed as:

wherein S is_TThe temperature sensitivity coefficient of the fiber Bragg grating can be expressed by the following formula:

wherein, S phi represents the humidity sensitive coefficient of the fiber Bragg grating, which can be expressed by the following formula:

according to the formula, the central wavelength change caused by the environmental temperature change can be calibrated through the functional relation between the linear interpolation temperature change and the fiber Bragg grating central wavelength drift amount, and the cross sensitivity problem under the high-temperature environment can be solved if the central wavelength drift amount caused by the environmental temperature change can be obtained.

In an embodiment of the specification, the humidity sensor is calibrated by using a saturated salt solution humidity calibration method, a central wavelength value of the fiber Bragg grating corresponds to a humidity value, humidity calibration is performed on the fiber Bragg grating humidity sensor by using humidity conditions corresponding to five saturated salt solutions of lithium chloride, magnesium chloride, potassium iodide, sodium chloride and potassium chloride according to a saturated salt solution and humidity comparison table described in standard ISOR483-1966, and a calibration result is shown in fig. 3.

In one illustrative embodiment, the relationship between the variation of the center wavelength of the sensor and the variation of the external environment temperature is as follows: Δ λ 0.0099 Δ T +0.04

Wherein, Δ λ represents the variation of the central wavelength of the fiber Bragg grating humidity sensor, and Δ T represents the variation of temperature. In the above formula, the Pearson's R distribution index of the fitting result is 0.99, R²The distribution index is 0.98, which shows that the linear fitting effect of the central wavelength variation and the temperature variation of the fiber Bragg grating humidity sensor is good.

In one embodiment, the temperature compensation method is mainly realized by obtaining each section of thermo-optic coefficient through section calibration, and humidity measurement in the range of 30-70 ℃ is carried out at intervals of 10 ℃ and temperature compensation is carried out on the basis of 30 ℃.

In an embodiment of the specification, the determining a temperature compensation coefficient according to an ambient temperature in a setting machine to compensate the central wavelength of the optical fiber Bragg grating specifically includes: the temperature is divided into two sections by using a sectional compensation method, and the humidity measurement in the range of 30-70 ℃ is subjected to temperature compensation according to the following rules:

When the temperature range is within 50-60 ℃, performing temperature compensation by taking 50 ℃ as a reference according to the formula:wherein T is more than or equal to 50 DEG c<60°c；

The central wavelength deviation value of the fiber Bragg grating humidity sensor predicted by the temperature compensation method is very close to the actual value measured by experiments, the average absolute error of the predicted wavelength deviation amount is 5.2%, and the maximum absolute error of the experimental value and the predicted value is less than 10%, which indicates that the compensation method has higher precision.

As shown in fig. 2, an embodiment of the present invention further provides a device for detecting humidity of exhaust gas of a fabric setting machine, including:

the temperature detection module 1, the signal processing module 2 and the data processing module 3;

the temperature detection module 1 includes: the system comprises an ASE broadband light source 1-1, a three-port optical fiber circulator 1-2 and an optical fiber Bragg grating humidity sensor 1-3;

the ASE broadband light source 1-1 is electrically connected with the three-port optical fiber circulator 1-2;

the three-port optical fiber circulator 1-2 is in bidirectional electrical connection with the optical fiber Bragg grating humidity sensor 1-3;

the edge filter 2-1 is electrically connected with the three-port optical fiber circulator 1-2;

the data processing module 3 includes: an upper computer 3-1;

the upper computer 3-1 is electrically connected with the dark current compensation circuit 2-5.

In one illustrative embodiment, the fiber Bragg grating humidity sensor 1-3 is provided with a fluorine-containing polyimide humidity-sensitive coating, the polyimide coating on the fiber Bragg grating humidity sensor is made of a polyimide material, the modified polyimide coating has a wet expansion coefficient of (6-9) multiplied by 10 < -5 >%, and when the humidity changes, the fiber Bragg grating is strained due to the deformation of the coating, so that the fiber Bragg grating can sense the humidity.

The polyimide humidity sensitive film is deformed due to external humidity change, so that the grid spacing of the optical fiber Bragg grating is changed, the central wavelength of the optical fiber Bragg grating is shifted, the quantity relation between the shift quantity of the central wavelength and the external humidity change is obtained by establishing a sensing model, an optical signal is converted into a digital signal through a signal processing module and is transmitted into an upper computer, the upper computer performs temperature compensation on the digital signal according to the environmental temperature, the problem of cross sensitivity is solved, the environmental humidity in the setting machine is obtained by performing humidity inversion calculation, the air exhaust rate of the setting machine can be controlled according to the humidity, the production efficiency is improved, the energy is saved, the emission is reduced, and the product quality is guaranteed.

In an embodiment of the specification, the reflected light of the fiber Bragg grating humidity sensor 1-3 is divided into two paths of light with equal intensity, one path of light is used as a reference beam, the other path of light is used as a measuring beam and is filtered by the edge filter 2-1, and the difference between the two paths of light is obtained by subtracting the two paths of light to obtain the light intensity difference between the measuring beam and the reference beam.

In one illustrative embodiment, the photoelectric conversion circuit 2-2 includes: PIN photodiode and current-voltage conversion circuit.

In an embodiment of the specification, the photoelectric conversion circuit 2-2 converts the light intensity of the measurement light into a voltage signal, the voltage signal needs to be amplified by the linear amplification circuit 2-3 and then passes through the low pass filter 2-4 to be filtered to remove high frequency noise interference, finally, a dark current compensation circuit 2-5 compensates the measurement error caused by the dark current of the PIN photodiode, and the electric signal is transmitted to the data processing module 3 to be subjected to a/D sampling.

In an embodiment in the specification, the optical fiber Bragg grating 1-3 reflects an optical signal with a specific wavelength according to the ambient humidity and then reaches the signal processing module 3 through the three-port optical fiber circulator 1-2, and comprises an edge filter 2-1, a photoelectric conversion circuit 2-2, a linear amplification circuit 2-3, a low-pass filter circuit 2-4 and a dark current compensation circuit 2-5.

The edge filter adopted in the embodiment is a transmission type filtering fiber chirped grating provided by Shenzhen Zhongke sensing technology Limited, and the shift amount of the center wavelength of the fiber Bragg grating is corresponding to the light intensity variation after filtering.

In an embodiment of the specification, a photoelectric conversion circuit 2-2 is formed by an LSIPD-UL0.3-PIN InGaAs photodiode provided by Beijing photosensitive technology, Inc. and an AD825 current-voltage conversion circuit chip, an optical signal emitted by an edge filter 2-1 is converted into a weak voltage value, and an NE5532 chip is adopted to design a linear amplification circuit 2-3 to amplify the voltage signal, so that the subsequent A/D sampling is facilitated. And then, a MAX275ACWP is adopted to design a second-order Butterworth low-pass filter 2-4 to process the amplified signal, so that the interference of high-frequency noise is eliminated. Finally, NE5532 is adopted to design a dark current compensation circuit 2-5, and errors generated by dark current are offset.

In an embodiment of the specification, the upper computer 3-1 of the data processing module selects a JZ2440 core board, mainly realizes compensation and humidity inversion calculation of the central wavelength of the fiber Bragg grating on a JZ2440 embedded development board, and realizes humidity inversion by using data obtained by humidity calibration to the maximum extent.

The embodiment of the invention has the following beneficial effects:

according to the method for detecting the humidity of the tail gas of the fabric setting machine, the external humidity changes to cause the modified polyimide humidity sensitive film to deform, so that the grid spacing of the optical fiber Bragg grating is changed, the central wavelength of the optical fiber Bragg grating is shifted, the quantity relation between the shift quantity of the central wavelength and the external humidity changes is obtained by establishing a sensing model, an optical signal is converted into a digital signal through a signal processing module and is transmitted into an upper computer, the upper computer performs temperature compensation on the digital signal according to the environmental temperature, the problem of cross sensitivity is solved, the environmental humidity in the setting machine is obtained by humidity inversion calculation, the air exhaust rate of the setting machine can be controlled according to the humidity, the production efficiency is improved, the energy is saved, the emission is reduced, and the product quality is guaranteed.

According to the device for detecting the humidity of the tail gas of the fabric setting machine, provided by the embodiment of the invention, the external humidity changes to cause the polyimide humidity sensitive film on the optical fiber Bragg grating to deform, so that the grid spacing of the optical fiber Bragg grating is changed, the central wavelength of the optical fiber Bragg grating drifts, an optical signal is converted into a digital signal through the signal processing module and is transmitted into the upper computer, the upper computer performs temperature compensation on the digital signal according to the environmental temperature, the problem of cross sensitivity is solved, the humidity inversion calculation is realized to obtain the environmental humidity in the setting machine, the air exhaust rate of the setting machine can be controlled according to the humidity, the production efficiency is improved, the energy is saved, the emission is reduced, and the product quality is ensured.

It should be noted that: the precedence order of the above embodiments of the present invention is only for description, and does not represent the merits of the embodiments. And specific embodiments thereof have been described above. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the device and server embodiments, since they are substantially similar to the method embodiments, the description is simple, and the relevant points can be referred to the partial description of the method embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

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Method and device for detecting humidity of tail gas of fabric setting machine

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