CN212871538U

CN212871538U - Small-size optic fibre fluorescence temperature measuring device

Info

Publication number: CN212871538U
Application number: CN202022134840.0U
Authority: CN
Inventors: 白智宏
Original assignee: Xi'an Mingtu Electronic Technology Co ltd
Current assignee: Xi'an Mingtu Electronic Technology Co ltd
Priority date: 2020-09-25
Filing date: 2020-09-25
Publication date: 2021-04-02
Anticipated expiration: 2030-09-25

Abstract

The utility model provides a small optical fiber fluorescence temperature measuring device, which comprises a probe, a light path part and a circuit part; the temperature measuring probe is connected with an input port of the light path part through an optical fiber, and the light path part is connected with the circuit part; the circuit part comprises an amplifying and conditioning circuit, an MCU singlechip control and processing circuit, a light source regulating and controlling circuit and a communication circuit; the light path part is connected with the input end of the amplifying and conditioning circuit, the output end of the amplifying and conditioning circuit is connected with the input end of the MCU singlechip control and processing circuit, the output end of the MCU singlechip control and processing circuit is connected with the input end of the light source regulating and controlling circuit, the output end of the light source regulating and controlling circuit is connected with the light path part, and the MCU singlechip control and processing circuit is connected with a communication circuit for sending out data. The utility model discloses a small optical fiber fluorescence temperature measuring device, which has high temperature measuring precision and high data refreshing rate; miniaturization, simple structure and lower cost.

Description

Small-size optic fibre fluorescence temperature measuring device

Technical Field

The utility model belongs to temperature measurement sensing technology, concretely relates to small-size optic fibre fluorescence temperature measuring device.

Background

Domestic temperature sensors also occupy the dominant position of thermal resistors and thermocouples. The electric sensor has the defects of poor long-term stability and low reliability, and can not meet the long-term temperature monitoring occasions. Metal sensors such as thermal resistors are easily interfered in the occasions of strong magnetic fields and strong electric fields, so that inaccurate temperature measurement is caused.

The optical fiber fluorescence temperature measurement sensing technology is a technology with a great development prospect, is not widely applied in some fields, and is particularly applied to some special industries, such as monitoring of medical treatment and high-voltage electrical equipment, petroleum exploitation and online detection in aviation aerospace.

At present, the domestic optical fiber fluorescence temperature measurement related products have the advantages of low temperature measurement precision, low data refresh rate, relatively complex structure and circuit (inconvenient integration) and higher cost.

It is noted that this section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

SUMMERY OF THE UTILITY MODEL

The utility model aims to the not enough of above-mentioned prior art, the utility model aims to provide a small-size optic fibre fluorescence temperature measuring device has realized the optic fibre fluorescence real-time temperature measurement of low cost, high accuracy.

In order to realize the purpose, the utility model adopts the following technical scheme:

the small optical fiber fluorescence temperature measuring device comprises an input port, a light path part and a circuit part, wherein the light path part is connected with the circuit part;

the circuit part comprises an amplifying and conditioning circuit, an MCU singlechip control and processing circuit, a light source regulating and controlling circuit and a communication circuit; the light path part is connected with the input end of the amplifying and conditioning circuit, the output end of the amplifying and conditioning circuit is connected with the input end of the MCU singlechip control and processing circuit, the output end of the MCU singlechip control and processing circuit is connected with the input end of the light source regulating and controlling circuit, the output end of the light source regulating and controlling circuit is connected with the light path part, and the MCU singlechip control and processing circuit is connected with a communication circuit for sending out data.

Furthermore, the temperature measuring probe adopts a fluorescent powder probe.

Furthermore, the optical fiber adopts a multimode optical fiber.

Furthermore, the light path part adopts a light splitting module.

Further, the light splitting module comprises a focusing lens, a first optical filter and a second optical filter; the first optical filter and the focusing lens are sequentially positioned on the light path, and a preset included angle is formed between the first optical filter and the light path; the second optical filter is arranged above the first optical filter and is parallel to the light path.

Further, the communication circuit adopts an RS485 communication circuit.

Furthermore, the temperature measuring probe comprises a fluorescent powder probe connected with the optical fiber, a probe protective layer for protecting the fluorescent powder probe, a heat-conducting filler for filling the gap and a sheath for protecting the temperature measuring probe and the optical fiber.

Further, the material of the sheath is polytetrafluoroethylene.

The utility model has the advantages that:

1. the utility model discloses a small optical fiber fluorescence temperature measuring device, which has high temperature measuring precision and high data refreshing rate; the device is miniaturized, simple in structure and low in cost;

2. the utility model discloses a small-size optic fibre fluorescence temperature measuring device realizes the real-time temperature measurement of-40 ℃ to 200 ℃ and precision +/-0.5 ℃.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of the amplification and conditioning circuit of the present invention;

FIG. 3 is a schematic diagram of the MCU single chip control and processing circuit of the present invention;

fig. 4 is a schematic diagram of a light source regulation circuit according to the present invention;

fig. 5 is a schematic structural diagram of the light splitting module of the present invention;

fig. 6 is a schematic structural view of the temperature probe of the present invention.

In the figure: 1-a temperature measuring probe; 2-a light path section; 3-a circuit part; 4-an amplifying and conditioning circuit; 5-MCU singlechip control and processing circuit; 6-light source regulation and control circuit; 7-a communication circuit; 8-a light splitting module; 9-an optical fiber; 10-a focusing lens; 11-a first optical filter; 12-a second optical filter; 13-a phosphor probe; 14-probe protection layer; 15-thermally conductive filler; 16-sheath.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The utility model discloses a principle of optic fibre fluorescence temperature measurement is: after being excited by light with certain wavelength, the fluorescent powder is excited to emit fluorescent energy. After the excitation disappears, the phosphor still emits light for a period of time (fluorescence afterglow), and the duration of the period of time depends on the characteristics of the phosphor and the ambient temperature. The fluorescence afterglow decays exponentially, the fluorescence lifetime is different at different environmental temperatures, and the temperature of the environment where the temperature measuring probe is located can be obtained by measuring the fluorescence lifetime, so that the temperature measurement is realized.

The invention provides a miniaturized small optical fiber fluorescence temperature measuring device.

The small optical fiber fluorescence temperature measuring device shown in fig. 1 comprises three blocks, namely a temperature measuring probe 1, an optical path part 2 and a circuit part 3. The temperature measuring probe 1 is connected to the input port of the optical path part 2 through an optical fiber 9, the optical signal is received through a photosensitive diode of the circuit part 3 after being conditioned, and the fluorescent signal is digitized after being processed by the circuit, so that temperature measurement is realized.

The circuit part 3 comprises an amplifying and conditioning circuit 4, an MCU singlechip control and processing circuit 5, a light source regulating and controlling circuit 6 and a communication circuit 7.

As shown in the amplifying and conditioning circuit 4 of fig. 2, the photodiode D1 in the amplifying and conditioning circuit 4 receives the fluorescent signal, and amplifies and conditions the fluorescent signal by the transconductance amplifier U3. The scheme optimizes an amplifying and conditioning circuit from two aspects; firstly, an operational amplifier with small input offset voltage, large gain and small input leakage current is selected, a resistor in a photoelectric detection circuit is a high-precision metal film resistor, and a capacitor is a ceramic capacitor with small temperature drift and relatively high precision. The photodiode amplifying circuit keeps a low input offset voltage, and the stability and reliability of the photodiode detection circuit are further improved; secondly, the design circuit is reasonably arranged, the operational amplifier and a photosensitive diode D1 node are protected by a protective ring, and cross wiring of input and output of the operational amplifier is avoided in order to reduce system noise.

The MCU singlechip control and processing circuit 5U1 shown in FIG. 3 takes the operation speed of the processor into full consideration in design, reduces the performance requirement on the processor, and improves the anti-interference capability of the circuit. Therefore, a singlechip with ultrahigh cost performance can be selected, and the singlechip is used for acquiring fluorescence waveform data by using an A/D acquisition module of the singlechip. Therefore, a 16-bit 5V single chip microcomputer with PWM, DMA, operational amplifier and advanced analog functions of a Microchip is selected. When the fluorescent waveform is collected, DMA (direct memory access) and A/D (analog/digital) collection are directly used for data interaction, so that the single chip microcomputer has more time to perform data operation, and the data refresh rate is further improved, and the current data refresh rate of the device is 50HZ (the data refresh rate of similar products is 2HZ-3 HZ). In order to reduce the fluctuation of accidental errors of temperature measurement values, the original data of the fluorescence signals are subjected to combined filtering treatment, namely, a median filtering method is adopted firstly to limit the fluctuation range of output data and remove larger or smaller accidental errors. And then, a sliding filtering method is carried out, so that accidental errors are further reduced, and the data are smoothed, so that the measurement result approaches to a real temperature measurement value.

The light source regulating circuit 6 shown in fig. 4 controls and adjusts the driving current of the LED1 to change the light emitting intensity of the LED 1. In order to simplify the circuit and improve the temperature measurement precision. The light source regulating and controlling circuit 6 adopts a singlechip with an operational amplifier (usually, a light source driving circuit needs an external operational amplifier) to drive the LED transmitting tube, and realizes closed-loop automatic regulation according to the intensity of a fluorescent signal. The intensity of the light source influences the intensity of the fluorescent signal, i.e. the stronger the light source intensity, the stronger the light intensity of the fluorescent signal. If the light intensity of the light source is too weak, the extraction of the fluorescent signal in the circuit is influenced, and the demodulation temperature value is influenced. If the light intensity of the light source is too strong, the fluorescent signal is severely distorted (peak clipping phenomenon), thereby affecting the demodulation temperature value.

The light path part 2 adopts a light splitting module 8, which comprises a focusing lens 10, a first filter 11 and a second filter 12, as shown in fig. 5.

Step 1: a light source regulating and controlling circuit 6 of the circuit part drives an LED emission tube, and the LED emits light beams with certain wavelengths.

Step 2: the light beam in step 1 is completely transmitted through the first optical filter 11.

And step 3: the transmitted beam in step 2 is collimated by the focusing lens 10.

And 4, step 4: and (3) allowing the collimated light beam in the step (3) to enter the optical fiber connector, irradiating the collimated light beam on the fluorescent powder on the end face of the optical fiber, exciting the fluorescent powder, and generating a fluorescent signal by the fluorescent powder after the LED emission tube is extinguished.

And 5: the fluorescence signal in step 4 is collimated by the optical fiber, the joint and the focusing lens, and then irradiates on the first optical filter 11, because the first optical filter 11 only reflects the fluorescence signal, the fluorescence signal is reflected to the second optical filter 12 through the first optical filter 11, and the fluorescence signal is transmitted to the LD receiving tube through the second optical filter 12. The LD receiving tube converts the optical signal into an electrical signal for circuit processing. The second filter 12 only transmits the fluorescence signal and reflects signals of other wavelengths, so as to remove interference of other wavelengths.

As shown in FIG. 6, the temperature measuring probe 1 adopts a single optical fiber design, i.e. excitation light and fluorescence are transmitted in the same optical fiber at the same time. The design scheme has the advantages that the overall dimension of the temperature measuring probe can be effectively reduced, and the temperature measuring probe can extend into a narrow temperature measuring part more conveniently, so that the most real temperature can be monitored. The temperature measuring probe comprises a fluorescent powder probe 12, a probe protective layer 14, a heat-conducting filler 15 and a sheath 16, and the manufacturing steps are as follows:

step 1: the fluorescent powder and the optical cement are uniformly mixed according to a certain proportion, and then are coated on the end face of the optical fiber 9, and after complete curing, the fluorescent powder probe 13 is formed.

Step 2: and then a layer of high-strength glue is coated outside the fluorescent powder probe 13, and after the high-strength glue is completely cured, a probe protection layer 14 is formed and has the strength for protecting the fluorescent powder probe.

And step 3: the sheath 16 is tightly fastened to the optical fiber 9 and the fluorescent powder probe 13, and the sheath 16 is made of polytetrafluoroethylene.

And 4, step 4: and then a layer of high-temperature heat-shrinkable tube is sleeved outside the fluorescent powder probe 13 and the sheath 16, and the gap is filled with a heat-conducting filler 15.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. A small-size optic fibre fluorescence temperature measuring device which characterized in that: comprises a temperature measuring probe (1), a light path part (2) and a circuit part (3); the temperature measuring probe (1) is connected to an input port of the light path part (2) through an optical fiber (9), and the light path part (2) is connected with the circuit part (3);

the circuit part (3) comprises an amplifying and conditioning circuit (4), an MCU singlechip control and processing circuit (5), a light source regulating and controlling circuit (6) and a communication circuit (7); light path part (2) with amplify and condition circuit (4) input and be connected, amplify and condition circuit (4) output with MCU single chip microcomputer control is connected with processing circuit (5) input, MCU single chip microcomputer control and processing circuit (5) output with light source regulation and control circuit (6) input is connected, light source regulation and control circuit (6) output with light path part (2) are connected, MCU single chip microcomputer control and processing circuit (5) are connected with communication circuit (7) that are used for sending data outward.

2. The miniature optical fiber fluorescence temperature measuring device of claim 1, wherein: the temperature measuring probe (1) adopts a fluorescent powder probe.

3. The miniature optical fiber fluorescence temperature measuring device of claim 2, wherein: the optical fiber (9) adopts a multimode optical fiber.

4. The miniature optical fiber fluorescence temperature measuring device of claim 3, wherein: the light path part adopts a light splitting module (8).

5. The miniature optical fiber fluorescence temperature measuring device of claim 4, wherein: the light splitting module (8) comprises a focusing lens (10), a first optical filter (11) and a second optical filter (12); the first optical filter (11) and the focusing lens (10) are sequentially positioned on the light path, and the first optical filter (11) and the light path form a preset included angle; the second optical filter (12) is arranged above the first optical filter (11), and the second optical filter (12) is parallel to the optical path.

6. The miniature optical fiber fluorescence temperature measuring device of claim 5, wherein: and the communication circuit (7) adopts an RS485 communication circuit.

7. The miniature optical fiber fluorescence temperature measuring device of claim 6, wherein: the temperature measuring probe (1) comprises a fluorescent powder probe (13) connected with the optical fiber (9), a probe protective layer (14) used for protecting the fluorescent powder probe (13), a heat-conducting filler (15) used for filling a gap and a sheath (16) used for protecting the temperature measuring probe (1) and the optical fiber (9).

8. The miniature optical fiber fluorescence temperature measuring device of claim 7, wherein: the material of the sheath (16) is polytetrafluoroethylene.