WO2023092779A1 - Photoelectric chilled mirror type dew point sensor - Google Patents

Abstract

A photoelectric chilled mirror type dew point sensor, comprising a control system, a dew condensation system (14), and a photoelectric detection system which are sequentially connected. The control system comprises a housing, and a PCB main control board (6), a PCB adapter board (8), and welding pins (9) which are sequentially mounted in the housing. The bottom and top of the PCB main control board (6) are respectively provided with an aviation connector (6-1) and a connecting base (6-2), and the aviation connector (6-1) passes through the bottom of the housing and is configured to be connected to an external electrical device; the connecting base (6-2) is connected to the PCB adapter board (8), and is further connected to the welding pins (9), and is connected to the dew condensation system (14) and the photoelectric detection system by means of the welding pins (9). In the photoelectric chilled mirror type dew point sensor, by means of the mirror surface plated with platinum by means of a semiconductor process and coated with an oil-resistant hydrophobic material, and software control, the anti-fouling self-cleaning effect is obtained, and the long-term working precision of the instrument is ensured; the problems of large size, high power consumption, high cost and the like of existing dew point instruments are effectively solved; the beneficial effects of compact and small structure, reduced power consumption, reduced cost, improved efficiency and prolonged service life are realized.

Description

A Photoelectric Chilled Mirror Dew Point Sensor technical field

The present invention relates to the technical field of dew condensation measurement, in particular to a photoelectric cold mirror dew point sensor.

Background technique

The dew point meter is an instrument for measuring the water vapor content in the gas. With the measurement of the gas temperature, the temperature and humidity of the gas can be obtained. Due to its high measurement accuracy and long-term stability and reliability, the optical chilled mirror dew point meter is widely used internationally as the transfer standard for measuring dew point and temperature and humidity in the metrology and testing industry.

Although the dew point meter has the above characteristics of high precision, long-term stability and reliability, its high price, frequent use and maintenance are unavoidable problems, and factors such as narrow measurement range and large instrument volume also limit the use scenarios.

Secondly, to ensure the high precision of the dew point meter, the measuring gas must be clean and free from pollution, or the mirror surface pollutants should be cleaned regularly, otherwise it is easy to be affected by the mirror surface pollutants and cause the deviation of the measured dew point, which will affect the accuracy of the instrument.

Moreover, the mirror surface of the existing dew point meter is made of large-sized copper plated with gold. The large inertia of the copper block leads to slow response speed, and the surface of the copper gold-plated process is easy to be dirty; and the large-scale gold-plated copper consumes cooling power, resulting in a small cooling temperature difference and a small dew point measurement range. .

In addition, due to the large power consumption of the existing dew point meter, the control system of the dew point meter is generally the structure of an external body. The main reasons for the large power consumption of the dew point meter are as follows: First, the existing control system of the dew point meter uses MOS tubes to adjust the output power, but the MOS tubes are large in size, which is not conducive to miniaturization, and will generate a large number of heat sources, making heat dissipation difficult; The reason is that the existing dew point meter control system is equipped with a display with high power consumption, which makes it difficult to reduce the power consumption of the whole dew point meter; the third is that the existing dew point meter condensation system requires a large cooling power and a Fourth, the existing dew point meter is separated from the condensation system of the thermometer used to measure the external temperature, which also leads to complex circuits and high power consumption. Since the control system of the dew point meter is an external body structure, the whole dew point meter is bulky, high in cost, inconvenient to carry, and has limited application scenarios; due to the external connection of the control system, it also requires an external control system, and it is difficult to measure the external temperature with a thermometer. It is integrated with the dew point system in the same detection chamber, which leads to the inconvenience of measurement, and further leads to the large volume and high cost of the whole dew point meter.

technical problem

The present invention aims to overcome at least one defect (deficiency) of the above-mentioned prior art, and provides a photoelectric chilled mirror dew point sensor, which is used to solve the problems of large volume and limited application scenarios of the existing dew point meter control system.

technical solution

In order to solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a photoelectric cold mirror dew point sensor, including a control system, a dew condensation system and a photoelectric detection system connected in sequence; PCB main control board, PCB adapter board and welding pins in the housing, the bottom and top of the PCB main control board are respectively provided with aviation joints and connecting seats, and the aviation joints pass through the bottom of the housing for connecting with the outside The electrical device is connected; the connection seat is connected with the PCB adapter board, and then connected with the welding pin, and the dew condensation system and the photoelectric detection system are connected through the welding pin.

In this technical solution, through high integration, an integrated PCB main control board is used to replace the desktop controller, so that the volume of the whole set of equipment can be reduced, so that it is easy to carry and use; by adopting an integrated PCB main control board, the original The large power consumption display reduces the power consumption of the whole machine and makes the heat dissipation performance of the PCB main control board meet the requirements.

Specifically, by arranging the PCB main control board in the housing, the solution of separating the PCB main control board and the measurement unit in the prior art is abandoned, and the dew point sensor is small, highly integrated, and easy to embed into other systems. wider. At the same time, since the PCB main control board is arranged in the casing, the cost of the dew point sensor is also saved. In addition, the aviation connector passes through the bottom of the shell so that the external electrical components can be directly connected to the aviation connector during use, thereby reducing production difficulty and cost and improving production efficiency.

Furthermore, since the PCB main control board is integrated in the housing, the photoelectric detection system can be directly connected to the condensation system, and then connected to the control system to realize the integrated setting of the entire dew point sensor, simplify the structure of the dew point sensor, and facilitate portability and use .

In one of the embodiments, the housing includes a bottom cover and a heat sink connected to each other; the PCB main control board, PCB adapter board and welding pins are arranged in the heat sink, and the bottom cover is a hollow structure, The aviation joint passes through the bottom cover and is exposed outside the bottom cover; a sealing ring is provided at the connection position between the aviation joint and the bottom cover.

In this technical solution, the heat dissipation of the PCB main control board and the dew condensation system can be performed through the metal heat conduction function of the heat sink. Specifically, the heat dissipation base dissipates heat from the dew condensation system, mainly to dissipate heat from the hot end of the dew condensation system. By setting a sealing ring between the aviation connector and the bottom cover, the connection position between the aviation connector and the bottom cover is sealed to ensure the sealing effect of the bottom of the heat sink, and to prevent water vapor from penetrating from the bottom of the heat sink, which will affect the performance of the PCB main control board. Specifically, when the heat sink and the bottom cover are in a detachable connection, a sealing ring may also be provided between the heat sink and the bottom cover to further ensure the sealing effect at the bottom of the heat sink.

In one of the embodiments, the top of the heat sink is provided with an opening, and the opening is covered with a pin position fixing plate for fixing solder pins; and the outline of the opening coincides with the outline of the pin position fixing plate.

By designing the contour of the opening of the cooling seat to coincide with the contour of the needle position fixing plate, on the one hand, the needle position fixing plate can be fixed, and on the other hand, the top of the heat dissipation seat can be closed by the needle position fixing plate.

In one of the embodiments, a silicone gasket is provided between the pin position fixing plate and the PCB adapter plate, and the solder pins are sequentially arranged on the PCB adapter plate, the silicone gasket, and the pin position from bottom to top. between the mounting plates and together seal the top of the heat sink.

On the one hand, the pin position fixing plate separates the solder pin from the metal heat sink to form an insulating effect, which ensures the electrical insulation requirements, and can effectively fix the dew condensation system so that the dew condensation system is in the center of the surface of the shell Location.

On the other hand, the top of the heat sink is sealed by setting a silicone gasket, and then the pin position fixing plate is matched with the top opening of the heat sink to achieve sealing, so that the inside of the heat sink is sealed to better protect the PCB main control board, so that It is not easily damaged by external water vapor or gas corrosion.

In one of the implementations, the PCB main control board is provided with a filter circuit, a communication circuit, a main control circuit, an analog circuit, and a refrigeration circuit; the filter circuit is used to filter out interference, so that the external power supply can The main control circuit, analog circuit and refrigeration circuit provide stable current input; specifically, the external power supply passes through the filter circuit to filter out common-mode interference and ripple interference. Supply power to the main control circuit, communication circuit, refrigeration circuit and analog circuit. So as to ensure that each circuit has a stable power input, so that the work is stable and the measurement results are accurate. The communication circuit is connected with an external electrical device through an aviation connector to realize data transmission; specifically, the main control circuit can be connected with an external host computer or external equipment through a communication circuit to transmit data to an external host computer or external equipment; at the same time, the external The host computer or external equipment can also read the sensor data through the communication circuit, and upgrade the firmware of the sensor.

The main control circuit is respectively connected to the communication circuit, the analog circuit and the refrigeration circuit, and is used to realize signal transmission and work control; specifically, the main control circuit realizes the precise measurement of the platinum resistor electrical signal of the dew condensation system through a high-precision ADC on the one hand, In order to obtain the temperature value; on the other hand, the main control circuit obtains the measurement value of the photoelectric detection system through a high-precision ADC, and controls the dew condensation state of the dew condensation system in real time. Wherein, the ADC is an analog-to-digital converter; the condensation state may be a state of whether condensation occurs, or a state of condensation thickness when condensation occurs. Then adjust the PWM duty cycle to adjust the voltage of the refrigeration circuit by adjusting the condensation state such as whether or not there is condensation and the thickness of the condensation. Specifically, the refrigeration circuit increases or decreases the refrigeration voltage to make the condensation system The dew condensation state quickly reaches the dynamic equilibrium state, which is the state when the dew condensation system just appears condensation. Finally, the photoelectric detection system is used to obtain the dew point value and the actual temperature value of the dew condensation system to achieve dynamic equilibrium, so as to calculate the relative humidity and other data.

The analog circuit is respectively connected to the dew condensation system and the photoelectric detection system through the connection socket for detecting and controlling signals, and the analog circuit is provided with a temperature measurement circuit, a mirror dew point measurement circuit and a photoelectric detection system respectively connected to the main control circuit signal. Measuring circuit; the mirror surface dew point measuring circuit is electrically connected to the dew condensation system, and the main control circuit controls the operation of the dew condensation system through the mirror surface dew point measuring circuit and the refrigeration circuit; the temperature measuring circuit and the photoelectric measuring circuit are respectively connected with the photoelectric detection system Electrically connected, the main control circuit controls the work of the photoelectric detection system through the photoelectric measurement circuit.

Specifically, on the one hand, the analog circuit uses precision operational amplifier circuits such as voltage follower and constant current source to make the electrical signal of the connected platinum resistance system more stable, so that the main control circuit can perform accurate measurement. On the other hand, the signal output between the main control circuit and the photoelectric detection system is stabilized by the constant current source. In addition, the analog circuit also amplifies the electrical signal of the photoelectric detection system through a precision amplifier circuit, so that the electrical signal of the photoelectric detection system is more stable.

The refrigerating circuit is connected to the dew condensation system through the connecting seat for cooling or heating. Specifically, the main control circuit can adjust the PWM duty cycle to the refrigeration circuit according to the dew condensation state detected by the photoelectric detection system, so as to adjust the power of the refrigeration circuit, so that the mirror quickly reaches the dew condensation balance state.

In one of the implementations, the cooling circuit is provided with a switching power supply IC, and the main control circuit outputs PWM with different duty ratios to the feedback terminal of the switching power supply IC, so that the switching power supply IC outputs different voltages, realizing The power of the refrigeration circuit is adjusted, so that the condensation system can quickly reach the dynamic balance of condensation.

Through the above-mentioned PWM duty cycle adjustment, the regulated output power with high efficiency and low loss is obtained, and the heat generation is also greatly reduced, so that the PCB main control board meets the performance requirements of the dew point sensor.

Further, the analog circuit is provided with a shielding cover to resist interference; and the work division of the filter circuit, communication circuit, main control circuit and refrigeration circuit on the PCB main control board is clear and well-organized, which can respond to work more quickly. , improve work efficiency and reduce power consumption.

In one of the embodiments, the dew condensation system includes a refrigeration stack and a thermometer, and the refrigeration stack is formed by stacking at least one level of refrigeration structures, and the top of the top refrigeration structure is a cold end, and the bottommost refrigeration structure The bottom of the structure is the hot end, and the thermometer is embedded in the top refrigeration structure; the hot end is in contact with the housing of the control system and conducts heat transfer; the upper surface of the cold end is glued with a lens , the lens is coated with an oil-resistant and hydrophobic material layer; or, the upper surface of the cold end is coated with a metal material layer as a mirror layer, and the mirror layer is coated with an oil-resistant and hydrophobic material layer; when The refrigeration stack is formed by a primary refrigeration structure, the top of the refrigeration structure is the cold end, the bottom of the refrigeration structure is the hot end, and the thermometer is embedded below the cold end; above the hot end The refrigerating structure area cover of the refrigerating stack is provided with an encapsulation platform, and the bottom of the encapsulation platform is sealed and connected with the upper surface of the hot end; when the refrigerating stack is formed by stacking two or more refrigerating structures, the outer cover of the top refrigeration structure is provided There is an encapsulation table; the bottom of the encapsulation table is in sealing connection with the upper surface of the sub-top refrigeration structure; the top of the encapsulation table is in airtight connection with an oil-resistant and hydrophobic material layer to seal the cold end.

Existing lenses are generally gold-plated copper, and their volume is relatively large, which does not meet the needs of users. Moreover, in the prior art, in order to facilitate the placement of the thermometer, it is generally necessary to install a heat-conducting copper block between the lens and the refrigeration stack, but the heat-conducting copper block will take away part of the cooling capacity, resulting in low cooling efficiency, so it is often necessary to use Relatively large power for refrigeration, and the obtained dew point temperature is limited. This also results in a large volume and high power consumption of the required controller. In this technical solution, by directly setting the lens on the cold end to reduce the loss of cooling capacity, the lens can quickly obtain cooling capacity in a short time, so as to reduce the power consumption of the refrigeration stack, so that the PCB main control board can cool The heap performs job control.

By coating the surface of the lens with an oil-resistant and hydrophobic layer, the surface of the lens is smooth and not easy to be polluted, thereby realizing the self-cleaning function of the condensation system, reducing the operation and maintenance of the staff, realizing real-time long-term online measurement, and improving the performance of the condensation system service life.

Furthermore, when the metal material layer is directly coated on the cold end as a mirror layer, since the thickness of the mirror layer is much smaller than the thickness of the lens, the cooling efficiency of the mirror layer is higher, and the dew point measurement capability is better. The response speed is faster, and the dew point that can be measured is lower.

Preferably, the metal material is platinum metal.

In this technical solution, the packaging platform is used to reduce the loss of cooling power. The packaging platform is a hollow quadrangular truss structure. The hollow quadrangular truss structure is used to match the structure of the cold end and reduce the cooling power loss. , Improve the response speed of the condensation system. Further, the thermometer extends out of the packaging table.

Further, the refrigeration stack is formed by stacking at least one-stage refrigeration structure, and the refrigeration stack is divided according to the number of stages of the stacked refrigeration structure. When the refrigeration stack is formed by stacking two-stage refrigeration structures, it is divided into two-stage refrigeration stack, wherein the second-stage refrigeration structure of the two-stage refrigeration stack is located above the first-stage refrigeration structure; when the refrigeration stack is formed by stacking three-stage refrigeration structures, it is divided into a three-stage refrigeration stack, wherein the three-stage refrigeration stack The first, second, and third-stage refrigeration structures are arranged sequentially from bottom to top, and so on, which will not be repeated here.

The top of the formed refrigeration stack is the cold end, and the bottom is the hot end; the packaging platform is at least covered outside the cold end to prevent the cooling of the cold end from being lost. Preferably, the refrigerating stack cover is arranged outside the top-level refrigerating structure of the refrigerating stack to better seal the cold end. Specifically, when the refrigeration stack is a first-stage refrigeration stack, the packaging table cover is arranged above the hot end; when the refrigeration pile is a secondary refrigeration pile, the packaging table cover is arranged on the secondary refrigeration pile outside the second-stage refrigeration structure of the three-stage refrigeration stack; when the refrigeration stack is a three-stage refrigeration stack, the packaging table cover is arranged outside the third-stage refrigeration structure of the three-stage refrigeration stack; and so on, which will not be repeated here.

Preferably, the refrigeration stack is formed by stacking two-stage refrigeration structures, and the two-stage refrigeration structures are divided into a first-stage refrigeration structure and a second-stage refrigeration structure stacked from bottom to top; the second-stage refrigeration structure The top is the cold end, the bottom of the first-stage refrigeration structure is the hot end, the thermometer is embedded in the second-stage refrigeration structure; the packaging table cover is arranged outside the second refrigeration structure, and the packaging table The bottom is in sealing connection with the upper surface of the first refrigeration structure.

In the technical solution, the thermometer is embedded in the second-stage refrigeration structure, which can make the structure of the dew condensation system more compact, and can also improve the detection accuracy. In the technical solution, the size of the refrigeration stack increases sequentially from top to bottom, so that the design is more convenient for refrigeration and the volume is reduced.

In one of the embodiments, the dew condensation system is embedded in the photoelectric detection system, and a dew condensation port for communicating with the outside is provided in the photoelectric detection chamber; the dew condensation system includes a refrigeration stack and a thermometer, The top of the refrigeration stack is a cold end, and the bottom is a hot end, and the thermometer is closely attached to the lower surface of the cold end; the outer wall of the dew condensation port is covered with a thermal insulation film; the thermal insulation There is a gap on the film, the gap is located at the position of the dew condensation port, and a lens is placed on the gap, and the lens is sealed and connected with the dew condensation port, and the bottom surface of the lens is close to the upper surface of the cold end, and is connected with the cold end The upper surface of the part works together to press the heat insulation film at the edge of the notch to seal the cold end; the cold end directly contacts the lens through the notch to conduct cold, and the lens is coated with an oil-resistant and hydrophobic material layer.

In this technical solution, the heat insulation film is used to seal the cold end to avoid loss of cooling capacity, thereby improving the dew point measurement capability and achieving the effect of measuring a lower dew point under the same conditions. And the use of heat insulation film for sealing can greatly reduce the cooling space, further reduce the loss of cooling capacity, and reduce the volume of the dew condensation system.

Furthermore, as another embodiment solution, the dew condensation system is embedded in the photoelectric detection system, and a dew condensation port for communicating with the outside is provided in the photoelectric detection chamber; the dew condensation system includes a refrigeration stack and a measurement A thermometer, the top of the refrigeration stack is a cold end, and the bottom is a hot end, and the thermometer is attached to the lower surface of the cold end; the upper surface of the cold end is coated with a metal material layer, As a mirror layer, the mirror layer is coated with an oil-resistant and hydrophobic layer; the oil-resistant and hydrophobic layer is sealed and connected to the dew condensation port, and the cold end is covered with a heat-insulating film, and the heat-insulating film is removed from the cold The lower surface of the end is close to the periphery of the cold end and extends to the inner wall of the dew condensation port, and is sealed and connected with the inner wall of the dew condensation port, so as to seal the dew condensation port together with the oil-resistant and hydrophobic layer.

In this technical solution, a metal material layer is directly coated on the upper surface of the cold end as a mirror layer, and a thermal insulation film is pasted on the lower surface of the cold end to the part in the photoelectric detection system to avoid the loss of cold energy and ensure The emitted light in the photoelectric detection system can be reflected by the mirror to ensure the accuracy of detection. This solution reduces system components, such as heat-conducting copper body, lens and packaging platform, greatly reduces the volume of the dew condensation system, thereby improving the response rate, reducing cooling loss, and improving the dew point measurement capability. Under the same other conditions, it can Measure lower dew points.

Specifically, when pasting the heat insulation film, the lower surface of the cold end to the periphery of the cold end is sealed by the heat insulation film, and the upper surface of the cold end is sealed by the metal material layer and the oil-resistant and hydrophobic layer, thereby jointly sealing the dew condensation port, It can prevent the cold energy of the cold end from escaping from the connection position between the cold end and the photoelectric detection system; the lower surface of the cold end and the surrounding of the cold end are sealed by a heat-insulating film, which can also prevent the loss of cold, so that The cold energy is quickly transferred to the metal material layer.

Further, the heat insulation film is a PTFE film. The PTFE membrane is extremely thin and has good sealing properties.

Through the power control of the dew point system, the power of the whole machine is greatly reduced. Among them, the power of the dew point sensor can be reduced to 5w or even lower; while the power of the traditional dew point sensor generally reaches 100w or even higher.

In one of the embodiments, the photoelectric detection system includes a detection chamber, a detection cover, a photoelectric detection element and a temperature detection element, the detection cover is arranged above the detection chamber, and a horizontally open A detection channel; the detection cavity includes a first installation cavity and a second installation cavity respectively arranged below and above the detection channel, and the dew condensation system and the photoelectric detection element are respectively arranged in the first installation cavity and the second installation cavity Inside, the photoelectric detection element is used to emit detection light, and the detection light emitted by the photoelectric detection element passes through the second installation cavity and is projected onto the dew condensation system in the first installation cavity; the temperature detection element is equipped with a temperature tube , the temperature tube and the temperature detection element are arranged above the photoelectric detection element and are arranged through the detection cover for detecting the temperature of the external environment.

In the prior art, since the temperature detection element needs to be connected with an external controller, the temperature detection element and the photoelectric detection element are set separately, that is, the temperature detection element is set separately. This results in a relatively large volume of the dew point sensor and many lines. In this technical solution, the temperature detection element and the photoelectric detection element are set on the same detection cavity, that is, the temperature detection element and the dew condensation system are integrated on the same probe, which simplifies the structure of the whole dew point sensor and makes the dew point sensor smaller and more compact. Easier to carry.

Further, the dew condensation system is sealed and connected with the first installation chamber, so as to prevent moisture, corrosive gas, etc. from entering the inner space of the first installation chamber from the dew condensation port and damaging the internal circuit of the dew condensation system. Specifically, the first installation chamber squeezes the packaging table of the dew condensation system, so that the packaging table, the cold end and the first installation chamber form a sealing effect, thereby preventing external water vapor, corrosive gas, etc. from entering the first installation from the dew condensation port. The internal space of the first installation cavity will damage the circuit; or the first installation cavity is glued to the heat insulation film of the dew condensation system, and then the inner space of the first installation cavity is closed to prevent external water vapor and corrosive gas from entering the first installation cavity from the dew condensation port. space, damage the internal circuit of the condensation system.

In one of the embodiments, a sealing ring is provided between the detection chamber and the housing; and the detection cover is in a sealed connection with the temperature tube. Specifically, when the detection cavity and the detection cover are detachably connected, a sealing ring is also provided between the detection cavity and the detection cover.

The working principle of the photoelectric cold mirror dew point sensor in this technical solution is: the temperature of the lens/mirror surface layer is reduced to the point where condensation or frost occurs on the surface of the lens/lens layer through cooling of the refrigeration stack. The photodetection element emits light and monitors the intensity of the light reflected by the lens/mirror surface. Through the photoelectric detection element, the change of the dew condensation thickness on the mirror surface can be monitored. When the thickness of condensation or frost is stable, that is, the condensation system reaches a dynamic equilibrium state, the lens/mirror surface temperature can be regarded as the dew point temperature, and the thermometer is used to measure the lens/mirror surface temperature to obtain the dew point temperature. By measuring the gas temperature and dew point temperature, according to the relationship between water vapor saturation pressure and temperature, the relative humidity of the gas can be calculated according to the definition of relative humidity.

Beneficial effect

Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention effectively solves the problem of large volume, high power consumption and high cost of the existing dew point instrument through the innovative condensation system, heat dissipation system and highly integrated main control system. , poor continuous working accuracy and other problems, it has the beneficial effects of compact structure, reduced power consumption, reduced cost, improved efficiency, and extended service life. The invention also adopts semiconductor technology to plate platinum and coat the mirror surface of oil-resistant and hydrophobic materials, and software control to obtain the effect of anti-fouling and self-cleaning, and ensure the long-term working accuracy of the instrument.

Description of drawings

Fig. 1 is a disassembled structure diagram of the present invention.

Fig. 2 is a sectional view of the present invention along B-B direction.

Fig. 3 is a schematic diagram of the structure of the welding pin of the present invention when it is fixed.

Fig. 4 is a three-dimensional structure diagram of the dew condensation system according to Embodiment 1 of the present invention.

Fig. 5 is a disassembled structure diagram of the dew condensation system according to Embodiment 1 of the present invention.

Fig. 6 is a disassembled structure diagram of the photoelectric detection system of the present invention.

FIG. 7 is a circuit structure diagram of the PCB main control board of the present invention.

FIG. 8 is a schematic structural diagram of the dew condensation system in Embodiment 2. FIG.

FIG. 9 is a schematic perspective view of the three-dimensional structure of the dew condensation system in Embodiment 3. FIG.

Fig. 10 is a schematic diagram of the disassembled structure of the dew condensation system in Embodiment 3.

FIG. 11 is a cross-sectional view of the detection chamber of the third embodiment.

FIG. 12 is an enlarged view of part A in FIG. 11 .

FIG. 13 is a cross-sectional view of the detection chamber in Embodiment 4.

FIG. 14 is an enlarged view of part B in FIG. 13 .

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1

As shown in FIG. 1 and FIG. 2 , this embodiment discloses a photoelectric cold mirror dew point sensor, which includes a control system, a dew condensation system 14 and a photoelectric detection system connected in sequence.

Among them, the control system includes a housing and a PCB main control board 6, a PCB adapter board 8 and solder pins 9 installed in the housing in sequence; the bottom and top of the PCB main control board 6 are respectively provided with an aviation connector 6-1 and a connecting seat 6-2, the aviation connector 6-1 passes through the bottom of the shell, and is used to connect with external electrical components; the connection seat 6-2 is connected to the PCB adapter board 8, and then connected to the welding pin 9, and connected through the welding pin 9 Condensation system 14 and photoelectric detection system.

Further, the housing includes a bottom cover 3 and a heat sink 11 connected to each other, and the PCB main control board 6 , the PCB adapter board 8 and the welding pins 9 are arranged in the heat sink 11 .

Wherein, the bottom cover 3 is a hollow structure, the aviation connector 6-1 passes through the bottom cover 3, and is exposed outside the bottom cover 3, so as to be connected with external electrical devices; in order to prevent external water vapor from entering the heat sink 11, the bottom cover 3 are respectively provided with a first sealing ring 4 and a second sealing ring 5, and the aviation connector 6-1 and the cooling seat 11 are sealed and connected to the bottom cover 3 through the first sealing ring 4 and the second sealing ring 5 respectively.

Specifically, the aviation joint 6-1 is fixedly connected to the bottom cover 3 through the nut 1, and the first sealing ring 4 is arranged between the outer wall of the aviation joint 6-1 and the inner wall of the bottom cover 3, and is used to prevent external water vapor from the aviation joint 6. The gap between -1 and the bottom cover 3 enters into the heat sink 11; the second sealing ring 5 is arranged between the heat sink 11 and the bottom cover 3 to prevent external water vapor from the gap between the heat sink 11 and the bottom cover 3 Enter the heat sink 11 inside.

Specifically, the bottom of the aviation joint 6-1 connected to the bottom cover 3 is also provided with a nut 1, and the first sealing ring 4 is further compressed by the nut 1; the bottom of the bottom cover 3 is pierced with a first The set of screws 2, the bottom cover 3 and the heat sink 11 are fixedly connected by the first set of screws 2, and then the second sealing ring 5 is further compressed to ensure the sealing.

Preferably, through the setting of the PCB main control board 6, the existing scheme of separating control and detection is abandoned, high integration is realized, the volume is smaller, it is easy to carry, it is convenient to embed into other systems, and the application scenarios are wider.

Further, the photoelectric detection system includes a detection cavity 15, a detection cover 18, a photoelectric detection element 16 and a temperature detection element 19, the detection cover 18 is arranged above the detection cavity 15, and the bottom of the detection cavity 15 and the heat dissipation seat of the PCB main control board 6 11 is connected at the top, and a third sealing ring 13 is provided at the connection position, so that the detection chamber 15 is connected with the heat sink 11 in a sealed manner.

Further, a fourth sealing ring 17 is provided between the top of the detection chamber 15 and the detection cover 18, so as to make the sealing connection between the detection chamber 15 and the detection cover 18, better protect the photoelectric detection element 16, and prevent it from being corroded by moisture. .

Further, the temperature detection element 19 is installed through the detection cover 18, and the bottom of the temperature detection element 19 is connected to the detection cavity 15, and the temperature detection element 19 is covered with a temperature tube 20, and the temperature tube 20 passes through the detection cover 18 and is exposed to the detection chamber. Cover 18 above.

Specifically, a third set of screws 21 is provided between the detection cover 18 and the detection cavity 15 , and the set of screws passes through the detection cover 18 and the detection cavity 15 sequentially from the top of the detection cover 18 .

As shown in Figure 1 and Figure 3, the top of the welding needle 9 is provided with a needle position fixing plate 12 for fixing the welding needle 9; the third sealing ring 13 is sleeved outside the needle position fixing plate 12; the PCB adapter plate 8 The upper surface is provided with a silicone gasket 10 , the welding needle 9 passes through the silicone gasket 10 , and the two ends of the welding needle 9 are respectively connected to the PCB adapter board 8 and the pin position fixing board 12 . The silicone gasket 10 is used to prevent water vapor from the condensation system from penetrating into the PCB adapter board 8 and the PCB main control board 6 below the silicone gasket 10 . Specifically, a second set of screws 7 is provided between the PCB adapter plate 8 , soldering pins 9 , the silicone gasket 10 and the pin position fixing plate 12 , and is fixed by the second set of screws 7 in sequence.

Specifically, the connection seat 6-2 above the PCB main control board 6 is plugged and connected to the PCB adapter board 8, the solder pin 9 is inserted on the PCB adapter board 8, and the PCB adapter board 8 is provided with a 9 one-to-one corresponding insertion holes. The silicone gasket 10 is arranged on the upper surface of the PCB adapter plate 8, and the silicone gasket 10 is also provided with insertion holes corresponding to the welding pins 9 one by one; the needle position fixing plate 12 is arranged above the silicone gasket 10, and the welding needles 9 passes through the silicone gasket 10 and is fixed on the needle position fixing plate 12. The contour of the pin position fixing plate 12 matches the contour of the top opening of the heat sink 11 to seal the heat sink 11. The pin position fixing plate 12 is also used to fix the solder pin 9, and then connect the solder pin 9 to the metal heat sink 11 Separated to form the effect of insulation, to ensure the requirements of electrical insulation, and can effectively fix the dew condensation system 14, so that the dew condensation system 14 is located at the center of the surface of the heat sink 11 .

Among them, the PCB adapter board 8 and the silicone gasket 10 are provided with holes for screws to pass through, and the needle position fixing plate 12 is provided with an installation port for screws to pass through, and the screws can also restrict the needle position fixing plate in the installation port. 12 moves to avoid deflection of the pin position fixing plate 12, thereby fixing the welding pin 9.

As shown in Figures 4 and 5, further, the dew condensation system 14 includes a refrigeration stack 22, a thermometer 23, and a lens 24, wherein the top of the refrigeration stack 22 is a cold end 222, and the bottom is a hot end 221. The thermometer 23 is embedded in the lower surface of the cold end portion 222 of the refrigeration stack 22, and the lens 24 is close to the upper surface of the refrigeration stack 22; and the lens 24 is a silicon chip, and the silicon chip is smaller in size and thinner in thickness; the lens 24 The surface of the lens 24 is coated with an oil-resistant and hydrophobic layer, so that the surface of the lens 24 is smooth and not easy to be polluted, and the self-cleaning function of the dew condensation system 14 is realized.

Preferably, the dimensions of the bottom of the refrigeration stack 22 are greater than the dimensions of the top of the refrigeration stack 22 .

Further, the refrigeration stack 22 of this embodiment is a two-stage refrigeration stack, and the two-stage refrigeration stack includes a first-stage refrigeration structure and a second-stage refrigeration structure stacked from bottom to top, wherein the outer cover of the second-stage refrigeration structure is provided with The packaging station 25 is used to reduce the cooling power loss of the cold end portion 222 . Specifically, the bottom of the packaging platform 25 is sealed and connected to the upper surface of the first-stage refrigeration structure, and the thermometer 23 extends out of the packaging platform 25; The size of the refrigeration structure matches, the top of the packaging platform 25 is sealed and connected with the lens 24, and the size of the lens 24 matches the size of the hollow structure at the top of the packaging platform 25.

As shown in Figure 6, the middle part of detection cavity 15 is provided with the detection channel 151 of transverse opening; The dew system 14 is respectively arranged in the second installation chamber and the first installation chamber of the detection chamber 15, and the top of the first installation chamber is provided with a dew condensation port 152 for communicating with the outside world, and the dew condensation port 152 communicates with the detection channel 151 for Condensation test. And the lens 24 fits on the dew condensation port 152, and is sealed and connected with the dew condensation port 152, thereby sealing the inside of the packaging table 25, and avoiding the loss of cold energy at the cold end. Specifically, the packaging platform 25 is made of silica gel, and when the dew condensation system 14 is fitted in the first installation cavity of the detection cavity 15, the lens 24 seals the dew condensation opening 152; and the first installation cavity squeezes the packaging platform 25, so that the refrigeration stack 22 The cold end 222 of the cold end 222, the packaging table 25 and the first installation cavity form a sealing effect among the three, preventing external water vapor, corrosive gas, etc. from entering the inner space of the first installation cavity from the dew condensation port, and damaging the circuit.

Specifically, the dew condensation system 14 is installed on the pin position fixing plate 12, and the hot end 221 of the refrigeration stack 22 is in contact with the pin position fixing plate 12, and conducts heat through the pin position fixing plate 12; 11 is sealed and connected, and the heat sink 11 is sealed and connected with the detection chamber 15 through the third sealing ring 13 to seal the dew condensation system 14, so that the refrigeration stack 22 and the thermometer 23 of the dew condensation system 14 are isolated from the outside world, effectively protecting the element Devices to prevent components from being corroded by moisture.

In this embodiment, the working principle of the optical chilled mirror dew point sensor is as follows: the temperature of the lens 24 is lowered to the point where condensation or frost occurs on the surface of the lens 24 through cooling by the refrigeration stack 22 . The photoelectric detection element 16 emits light, and monitors the light intensity of the light reflected by the surface of the lens 24 . Through the photoelectric detection element 16, the change of the dew condensation thickness on the mirror surface can be monitored. When the thickness of condensation or frost is stable, that is, the condensation system reaches a dynamic equilibrium state, the temperature of the lens 24 can be regarded as the dew point temperature, and the thermometer 23 is used to measure the temperature of the lens 24 to obtain the dew point temperature. By measuring the gas temperature and dew point temperature, according to the relationship between water vapor saturation pressure and temperature, the relative humidity of the gas can be calculated according to the definition of relative humidity.

As shown in Figure 7, specifically, the PCB main control board 6 is provided with a filter circuit 61, a communication circuit 62, a main control circuit 63, an analog circuit 64 and a refrigeration circuit 65; the filter circuit 61 is used to filter out interference, so that the external power supply Provide stable current input to the communication circuit 62, the main control circuit 63, the analog circuit 64 and the refrigeration circuit 65; specifically, the external power supply passes through the filter circuit 61 to filter out common-mode interference and ripple interference. Supply power to the main control circuit 63 , the communication circuit 62 , the cooling circuit 65 and the analog circuit 64 . So as to ensure that each circuit has a stable power input, so that the work is stable and the measurement results are accurate.

The communication circuit 62 is connected with an external electrical device through the aviation connector 6-1 to realize data transmission; specifically, the main control circuit 63 can be connected with an external host computer or external equipment through the communication circuit 62 to transmit data to the external host computer or external equipment. Data; at the same time, the external host computer or external equipment can also read the sensor data through the communication circuit 62, and upgrade the firmware of the sensor.

The main control circuit 63 is connected to the communication circuit 62, the analog circuit 64 and the refrigeration circuit 65 respectively, and is used to realize signal transmission and work control; The signal is accurately measured to obtain the temperature value; on the other hand, the main control circuit 63 obtains the measured value of the photoelectric detection system through a high-precision ADC, and controls the dew condensation state of the lens 24 of the dew condensation system 14 in real time. Then adjust the PWM duty cycle to realize the voltage adjustment of the refrigeration circuit 65 according to the condensation state such as whether condensation is formed or the thickness of the condensation, and the refrigeration circuit 65 increases the refrigeration voltage or reduces the refrigeration voltage, so that the condensation system 14 The dew condensation state of the lens 24 quickly reaches a dynamic balance. Finally, the photoelectric detection system is used to obtain the dew point value and the actual temperature value of the lens 24 to achieve dynamic balance, so as to calculate data such as relative humidity. Among them, the ADC is an analog-to-digital converter.

The analog circuit 64 is respectively connected to the dew condensation system 14 and the photoelectric detection system through the connection seat 6-2 for detection and control signals, and the analog circuit 64 is provided with a temperature measurement circuit 641, a mirror surface measurement circuit, and a mirror surface measurement circuit respectively connected to the main control circuit 63 signal. The dew point circuit 642 and the photoelectric measurement circuit 643; the mirror surface dew point measurement circuit 642 is electrically connected with the dew condensation system, and the main control circuit 63 controls the work of the dew condensation system 14 through the mirror surface dew point measurement circuit 642; the temperature measurement circuit 641 and the photoelectric measurement circuit 643 are connected with the dew condensation system respectively The photoelectric detection system is electrically connected, and the main control circuit 63 controls the operation of the photoelectric detection system through the temperature measurement circuit 641 and the photoelectric measurement circuit 643 . Specifically, on the one hand, the analog circuit 64 makes the electric signal of the connected platinum resistor of the dew condensation system 14 more stable through precision operational amplifier circuits such as voltage follower and constant current source, so that the main control circuit 63 can perform accurate measurement. On the other hand, the signal output between the main control circuit 63 and the photoelectric detection system is stabilized by the constant current source. In addition, the analog circuit 64 also amplifies the electrical signal of the photoelectric detection system through a precision amplifier circuit, so as to make the electrical signal of the photoelectric detection system more stable.

The refrigeration circuit 65 is connected to the dew condensation system 14 through the connection socket for cooling or heating. Specifically, the main control circuit 63 can adjust the PWM duty ratio to the refrigeration circuit 65 according to the dew condensation state detected by the photoelectric detection system, so as to adjust the power of the refrigeration circuit 65, so that the mirror quickly reaches the dew condensation balance state, The dynamic equilibrium state is the state when the dew condensation system has just condensed.

Further, the cooling circuit 65 is provided with a switching power supply IC, and the main control circuit 63 outputs PWMs with different duty ratios to the feedback terminal of the switching power supply IC, so that the switching power supply IC outputs different voltages to realize power regulation of the cooling circuit 65, Therefore, the dew condensation system 14 quickly reaches the dynamic balance of dew condensation.

Through the above PWM duty ratio adjustment, the regulated output power with high efficiency and low loss is obtained, and the calorific value is also greatly reduced, so that the PCB main control board 6 meets the performance requirements of the dew point sensor.

Embodiments of the present invention

Example 2

As shown in Figure 8, the difference between this embodiment and Embodiment 1 is that no lens is provided on the refrigeration stack 22, but a mirror layer is formed by coating the upper surface of the cold end portion 222 with a metal material layer, Then coat the oil-resistant and hydrophobic material layer on the mirror surface layer to avoid the adhesion of external oil stains. Wherein, the oil-repellent and hydrophobic material layer is in the first installation cavity, is sealed and connected with the packaging platform 25, and cooperates with the packaging platform 25 to cling to the lower surface of the dew condensation opening. Such an arrangement not only ensures the requirement of dew condensation and the requirement of sealing the internal space of the refrigeration stack 22, but also makes the volume of the entire dew condensation system smaller and the cooling efficiency higher. Specifically, the metal material layer is a metal platinum layer.

Example 3

As shown in Figures 9-12, the difference between this embodiment and Embodiment 1 is that the cold end portion 222 of the refrigeration stack 22 is not covered with an encapsulation platform, but the outer wall surface of the dew condensation port is covered with heat insulation Membrane 26 to avoid cooling loss. Wherein, a gap is provided on the heat insulating film 26, and the gap is located on the upper surface of the cold end portion 222. The lens 24 is placed on the gap, and the lens 24 is sealed and connected to the dew condensation port, and the bottom surface of the lens 24 is close to the upper surface of the cold end portion 222. surface, and cooperate with the upper surface of the cold end 222 to press the insulation film on the edge of the gap to seal the cold end 222; meanwhile, the cold end 222 directly contacts the lens 24 through the gap and conducts cold.

Specifically, the dew condensation system 14 is installed in the first installation cavity of the detection chamber 15, and the heat insulation film 26 is placed on the outer wall of the dew condensation opening, and is close to the dew condensation opening; the lens 24 is placed on the heat insulation film 26, and the lens 24 and the The dew condensation port in the first installation cavity is sealed and connected, and the lens 24 presses the heat insulation film 26 on the dew condensation port, and the edge of the heat insulation film 26 is closely connected with the cold end 222 to seal the cold end 222, so that the lens 24 , the thermal insulation film 26 and the cold end portion 222 are sealed and connected, which not only ensures the cooling effect, but also prevents external water vapor and corrosive gas from entering the inner space of the first installation cavity from the dew condensation port and damaging the circuit. Wherein, the heat insulating film 26 is a PTFE film.

Example 4

As shown in Figures 13-14, the difference between this embodiment and Embodiment 1 is that the cold end portion 222 is not covered with a packaging platform, but the cold end portion 222 is covered with a heat insulating film 26, In order to avoid the loss of cold; moreover, no eyeglass is provided on the cold end 222, but a mirror layer is formed by coating the upper surface of the cold end 222 with a metal material layer, and then the oil-resistant and hydrophobic material layer is coated on the mirror layer , to avoid the adhesion of external oil.

Specifically, after the metal material layer and the oil-repellent and hydrophobic material layer are coated on the upper surface of the cold end portion 222, the dew condensation system 14 is installed in the first installation cavity of the detection cavity 15, and the metal material layer and the oil-resistant and hydrophobic layer The upper surface of the cold end portion 222 can be effectively sealed; the heat insulation film 26 is in sealing connection with the lower surface of the cold end portion 222 . Specifically, the heat insulation film 26 extends from the lower surface of the cold end portion 222 close to the periphery of the cold end portion 222 into the first installation cavity of the detection chamber 15, and the heat insulation film 26 is close to the dew condensation port in the first installation cavity. wall, and the wall surface of the cold end 222 and the oil-resistant hydrophobic material layer are adhesively connected and act together to seal and compress the cold end 222, effectively preventing external water vapor and corrosive gas from entering the first installation cavity from the dew condensation port internal space, damage to circuits. The heat insulation film 26 seals the lower surface and surroundings of the cold end portion 222, and seals with the surroundings of the dew condensation port, so as to avoid the loss of cooling capacity of the cold end portion 222 and ensure the cooling effect. Such setting not only ensures the requirement of condensation, but also makes the volume of the entire condensation system 14 smaller and the refrigeration efficiency is higher. Wherein, the thermal insulation film 26 is a PTFE film, and the metal material layer is a metal platinum layer.

Claims (10)

1. A photoelectric cold mirror dew point sensor, including a control system, a dew condensation system and a photoelectric detection system connected in sequence; it is characterized in that the control system includes a housing and a PCB main control board and a PCB transfer board installed in the housing in sequence board and welding pins, the bottom and top of the PCB main control board are respectively provided with aviation joints and connection seats, and the aviation joints pass through the bottom of the housing for connecting with external electrical devices; the connection seats are connected to the PCB The adapter board is connected, and then the welding pin is connected, and the dew condensation system and the photoelectric detection system are connected through the welding pin.
2. The photoelectric cold mirror type dew point sensor according to claim 1, wherein the housing includes a bottom cover and a heat sink connected to each other;

   The PCB main control board, PCB adapter board and welding pins are arranged in the heat sink, the bottom cover is a hollow structure, the aviation connector passes through the bottom cover, and is exposed outside the bottom cover; the aviation connector and A sealing ring is provided at the connecting position of the bottom cover.
3. A kind of photoelectric cold mirror type dew point sensor according to claim 2, it is characterized in that, the top of described cooling seat is provided with opening, and described opening is covered with needle position fixing plate, is used for fixing welding needle; And described The outline of the opening coincides with the outline of the needle position fixing plate;

   A silicone gasket is provided between the pin position fixing plate and the PCB adapter plate, and the welding pins are sequentially inserted between the PCB adapter plate, the silicone gasket and the pin position fixing plate from bottom to top, and are jointly sealed top of heat sink.
4. A kind of photoelectric cold mirror type dew point sensor according to claim 1, is characterized in that, described PCB main control board is provided with filter circuit, communication circuit, main control circuit, analog circuit and refrigeration circuit;

   The filter circuit is used to filter out interference, so that the external power supply provides stable current input to the communication circuit, main control circuit, analog circuit and refrigeration circuit;

   The communication circuit is connected to an external electrical device through an aviation connector to realize data transmission;

   The main control circuit is respectively connected to the communication circuit, the analog circuit and the refrigeration circuit for realizing signal transmission and work control;

   The analog circuit is respectively connected to the dew condensation system and the photoelectric detection system through the connection socket for detecting and controlling signals, and the analog circuit is provided with a temperature measurement circuit, a mirror dew point measurement circuit and a photoelectric detection system respectively connected to the main control circuit signal. Measuring circuit; the mirror surface dew point measuring circuit is electrically connected to the dew condensation system, and the main control circuit controls the operation of the dew condensation system through the mirror surface dew point measuring circuit and the refrigeration circuit; the temperature measuring circuit and the photoelectric measuring circuit are respectively connected with the photoelectric detection system Electrically connected, the main control circuit controls the work of the photoelectric detection system through the photoelectric measurement circuit;

   The refrigerating circuit is connected to the dew condensation system through the connecting seat for cooling or heating.
5. The photoelectric cold mirror dew point sensor according to claim 4, wherein a switching power supply IC is arranged on the refrigeration circuit, and the main control circuit outputs PWMs with different duty ratios to the feedback terminal of the switching power supply IC , so that the switching power supply IC outputs different voltages to realize the power regulation of the refrigeration circuit, so that the condensation system can quickly reach the dynamic balance of condensation.
6. The photoelectric cold mirror dew point sensor according to claim 1, wherein the dew condensation system includes a refrigeration stack and a thermometer, the refrigeration stack is formed by stacking at least one refrigeration structure, and the top cooling The top of the structure is the cold end, the bottom of the bottommost refrigeration structure is the hot end, and the thermometer is embedded in the topmost refrigeration structure; the hot end is in contact with the housing of the control system and conducts heat transfer;

   A lens is adhered to the upper surface of the cold end, and the lens is coated with an oil-resistant and hydrophobic material layer;

   Or, the upper surface of the cold end is coated with a metal material layer as a mirror layer, and the mirror layer is coated with an oil-resistant and hydrophobic material layer;

   When the refrigeration stack is formed by a primary refrigeration structure, the top of the refrigeration structure is the cold end, the bottom of the refrigeration structure is the hot end, and the thermometer is embedded below the cold end; the hot end The cooling structure area cover above is provided with an encapsulation platform, and the bottom of the encapsulation platform is in sealing connection with the upper surface of the hot end;

   When the refrigeration stack is formed by stacking two or more refrigeration structures, the outer cover of the topmost refrigeration structure is provided with an encapsulation platform; the bottom of the encapsulation platform is sealed and connected to the upper surface of the second-level refrigeration structure;

   The top of the encapsulation platform is hermetically connected with the oil-resistant and hydrophobic material layer to seal the cold end.
7. The photoelectric cold mirror dew point sensor according to claim 1, wherein the dew condensation system is embedded in the photoelectric detection system, and the photoelectric detection cavity is provided with a dew condensation port for communicating with the outside world; The dew condensation system includes a refrigeration stack and a thermometer, the top of the refrigeration stack is a cold end, and the bottom is a hot end, and the thermometer is closely attached to the lower surface of the cold end;

   The outer wall surface of the dew condensation port is covered with a thermal insulation film; the thermal insulation film is provided with a gap, the gap is located at the position of the dew condensation port, and a lens is placed on the gap, and the lens is sealed and connected to the dew condensation port , and the bottom surface of the lens is close to the upper surface of the cold end, and works together with the upper surface of the cold end to press the heat insulation film on the edge of the gap to seal the cold end; the cold end directly contacts the lens through the gap To conduct cold, the lens is coated with an oil-resistant and hydrophobic material layer.
8. The photoelectric cold mirror dew point sensor according to claim 1, wherein the dew condensation system is embedded in the photoelectric detection system, and the photoelectric detection cavity is provided with a dew condensation port for communicating with the outside world; The dew condensation system includes a refrigeration stack and a thermometer, the top of the refrigeration stack is a cold end, and the bottom is a hot end, and the thermometer is closely attached to the lower surface of the cold end;

   The upper surface of the cold end is coated with a metal material layer as a mirror layer, and the mirror layer is coated with an oil-resistant and hydrophobic layer; the oil-resistant and hydrophobic layer is sealed and connected to the dew condensation port, and the cold end The outside is covered with a thermal insulation film, and the thermal insulation film extends from the lower surface of the cold end close to the periphery of the cold end to the inner wall surface of the dew condensation port, and is sealed and connected with the inner wall surface of the dew condensation port to resist oil and water. The layers work together to seal the condensation opening.
9. A photoelectric cold mirror dew point sensor according to claim 1, wherein the photoelectric detection system includes a detection cavity, a detection cover, a photoelectric detection element and a temperature detection element, and the detection cover is arranged above the detection cavity , the middle part of the detection chamber is provided with a laterally open detection channel;

   The detection cavity includes a first installation cavity and a second installation cavity respectively arranged below and above the detection channel, the dew condensation system and the photoelectric detection element are respectively arranged in the first installation cavity and the second installation cavity, so The photoelectric detection element is used to emit detection light, and the detection light emitted by the photoelectric detection element passes through the second installation cavity and is projected onto the dew condensation system in the first installation cavity; the temperature detection element is equipped with a temperature tube, the The temperature tube and the temperature detection element are arranged above the photoelectric detection element and are arranged through the detection cover for detecting the temperature of the external environment.
10. The photoelectric cold mirror dew point sensor according to claim 9, wherein a sealing ring is provided between the detection cavity and the housing; the detection cover is sealed and connected to the temperature tube.