High-dew-point gas detection sensor

Abstract

The invention relates to the technical field of chilled mirror dew-point instruments, in particular to a high-dew-point gas detection sensor which comprises a probe body, a photoelectric detection unit and a mirror surface condensation unit, the probe body is provided with a test cavity used for circulation of gas to be detected, the mirror surface condensation unit is installed at the bottom of the test cavity, and the photoelectric detection unit is connected with the mirror surface condensation unit. The light detection unit is installed at the top of the test cavity, a heat conduction shell is installed on the probe body on the outer side of the test cavity, an air inlet and an air outlet which are used for being communicated with the test cavity are formed in the outer side of the heat conduction shell, and a first temperature control unit is installed in the heat conduction shell and used for heating the heat conduction shell; the temperature in the test cavity is raised to 10 DEG C or above of the dew point of the to-be-tested gas, it is guaranteed that the high-dew-point gas flows through the mirror surface in a gas state and is cooled and dewed only at the mirror surface, and verification of the sensor in the high-dew-point range is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of cold mirror dew point instruments, in particular to a high dew point gas detection sensor. Background Art

[0002] The detection of gas dew point plays a key role in environmental monitoring and process control, and the chilled mirror dew point meter is usually the first choice for detection equipment due to its high precision. The basic principle of the chilled mirror dew point meter is that gases with different water vapor content will condense on the mirror surface at different temperatures. A photoelectric detection system is used to detect the dew layer and measure the temperature at the time of condensation, which is the dew point temperature of the gas.

[0003] As the dew point increases, the water content in the gas increases geometrically. For example, when the dew point of the gas changes from 20°C to 25°C, the water content increases from 17g / m3 to 25g / m3. When the dew point temperature of the gas changes from 90℃ to 95℃, its water content changes from 407g / m3 to 491g / m3, and the increment is as high as 84g / m3. In the process of controlling the temperature of the mirror, the mirror temperature must be higher than the dew point and lower than the dew point. When the mirror temperature is lower than the dew point, the mirror quickly condenses water. When measuring low-humidity dew point gas, it is not easy to form aggregated liquid water due to the small absolute water content. However, when detecting high dew point gas, due to the high absolute humidity, aggregated water droplets are easily formed in the test cavity of the cold mirror dew point meter. The water droplets converge around the mirror, fill or even submerge the entire mirror, resulting in the inability of the photoelectric detection system to accurately identify the dew layer. This makes it impossible for the traditional cold mirror dew point meter to calibrate the high dew point range. Therefore, it is urgent to develop a cold mirror dew point meter sensor suitable for high dew point gas detection. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a high dew point gas detection sensor.

[0005] The technical solution of the present invention is: a high dew point gas detection sensor, comprising a probe body, a photoelectric detection unit and a mirror condensation unit, the probe body having a test cavity for circulating the gas to be detected, the mirror condensation unit installed at the bottom of the test cavity, the photodetection unit installed at the top of the test cavity, a heat-conducting shell installed on the probe body outside the test cavity, an air inlet and an air outlet for communicating with the test cavity are opened on the outside of the heat-conducting shell, and a first temperature control unit is installed in the heat-conducting shell to heat the heat-conducting shell. By installing a heat-conducting shell with a first temperature control unit on the outside of the probe body, the first temperature control unit heats the heat-conducting shell, and the temperature in the test cavity is raised to above the dew point of the gas to be detected. At the same time, the greater the difference between the temperature in the test cavity and the dew point value of the gas to be detected, the easier it is for the water to evaporate, and the less likely it is to form liquid condensed water in the test cavity, and then keep the environment around the mirror in a dry state, and the high dew point gas flows through the mirror in a gaseous state, and only cools and condenses at the mirror, completing the detection of the high dew point gas.

[0006] The probe body includes a detector and a heat-conducting seat connected in sequence from top to bottom. The test cavity is arranged in the detector in a transverse direction. A first installation cavity for installing a photoelectric detection unit is provided on the top of the detector. A second installation cavity connected to the test cavity and used to install a mirror condensation unit is provided on the top of the heat-conducting seat. A second temperature control unit is installed in the heat-conducting seat to heat the heat-conducting seat. A second temperature control unit is added below the probe body. Through the thermal conductivity of the heat-conducting seat, the heat of the second temperature control unit is transferred to the cooler to neutralize the heat loss caused by the heat dissipation of the heat-conducting shell due to the environment, thereby further maintaining the high temperature environment in the test cavity.

[0007] The heat-conducting shell is a cover structure with an opening at the lower end. The opening of the heat-conducting shell is provided with an internal threaded portion, and the upper end of the heat-conducting seat is provided with an external threaded portion matched with the internal threaded portion.

[0008] A lower cavity is provided in the thermal seat, and a control adapter board is provided in the lower cavity, which is electrically connected to the photoelectric detection unit, the mirror condensation unit and the second temperature control unit in sequence. The control adapter board is communicatively connected to the control system of the dew point meter via a main connector installed at the bottom of the thermal seat.

[0009] An upper cavity is provided in the heat-conducting housing, a temperature-control circuit board electrically connected to the first temperature-control unit is provided in the upper cavity, a first auxiliary connector electrically connected to the temperature-control circuit board is installed on the heat-conducting housing, a second auxiliary connector electrically connected to the control adapter board is installed at the bottom of the heat-conducting seat, and the first auxiliary connector and the second auxiliary connector are communicatively connected via a plug connector. The control signals of the first temperature-control unit and the second temperature-control unit are integrated on a control adapter board through the communication connection between the first auxiliary connector and the second auxiliary connector, thereby improving the integration of the sensor.

[0010] One end of the gas inlet is connected to a sample feeding pipeline, and the outside of the sample feeding pipeline is wrapped with a heating belt, and the temperature of the heating belt is not lower than the temperature of the sample gas. Wrapping the heating belt on the sample feeding pipeline can prevent the gas to be measured from condensing in advance, thereby reducing the water content and affecting the measurement result.

[0011] The beneficial effects of the present invention are as follows: the device installs a heat-conducting shell with a first temperature control unit on the outside of the probe body, and the first temperature control unit heats the heat-conducting shell to raise the temperature in the test cavity to above the dew point of the gas to be tested, thereby keeping the environment around the mirror in a dry state, thereby ensuring that the high dew-point gas flows through the mirror in a gaseous state and cools and condenses only at the mirror surface, thereby completing the detection of the high dew-point gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a cross-sectional schematic diagram of the present invention; Figure 3 It is a disassembly schematic diagram of the present invention; Figure 4 It is a new working principle diagram of the present utility model.

[0013] Figure numerals: 1. Probe body; 101. Detector; 102. Thermal seat; 103. External threaded portion; 104. Test cavity; 105. First installation cavity; 106. Second installation cavity; 107. Lower cavity; 108. Circuit channel; 2. Thermal shell; 201. Air inlet; 202. Air outlet; 203. Internal threaded portion; 204. Upper cavity; 3. Photoelectric detection unit; 4. Mirror condensation unit; 5. First temperature control unit; 6. Second temperature control unit; 7. Control adapter board; 8. Temperature control circuit board; 9. Main connector; 10. First auxiliary connector; 11. Second auxiliary connector; 12. Heating belt; 13. Temperature control equipment; 14. Control system. DETAILED DESCRIPTION

[0014] In order to enable those skilled in the art to better understand the technical solution in the present invention, the technical solution in the present invention is clearly and completely described below in conjunction with the accompanying drawings. Other embodiments obtained by those skilled in the art without making any creative work should all fall within the scope of protection of the present invention.

[0015] like Figure 1 and Figure 2As shown, the present invention provides a high dew point gas detection sensor, including a probe body 1, a photoelectric detection unit 3 and a mirror condensation unit 4, the probe body 1 is provided with a test cavity 104 for circulating the gas to be detected, the mirror condensation unit 4 is installed at the bottom of the test cavity 104, and the light detection unit is installed at the top of the test cavity 104. The detection light emitted by the photoelectric detection unit 3 passes through the test cavity 104 and is projected onto the mirror surface of the mirror condensation unit 4, and receives the electrical signal generated by the light reflected by the mirror, so as to detect the condensation state of the mirror condensation unit 4.

[0016] A heat-conducting shell 2 is installed on the probe body 1 outside the test cavity 104, and an air inlet 201 and an air outlet 202 for communicating with the test cavity 104 are provided on the outside of the heat-conducting shell 2. A first temperature control unit 5 is installed in the heat-conducting shell 2 to heat the heat-conducting shell 2. By installing the heat-conducting shell 2 with the first temperature control unit 5 on the outside of the probe body 1, the first temperature control unit 5 heats the heat-conducting shell 2, thereby raising the temperature in the test cavity 104 to above the dew point of the gas to be tested. At the same time, the greater the difference between the temperature in the test cavity 104 and the dew point value of the gas to be tested, the easier it is for the water to evaporate, and the less likely it is to form liquid condensed water in the test cavity 104. Specifically in this embodiment, the temperature difference is generally maintained at about 10°C, and then the environment around the mirror surface is kept in a dry state, and the high dew point gas flows through the mirror surface in a gaseous state, and only cools and condenses at the mirror surface, completing the detection of the high dew point gas.

[0017] like Figure 2 As shown, the probe body 1 includes a detector 101 and a thermal seat 102 which are connected in sequence from top to bottom, the test cavity 104 is arranged in the detector 101 in a transverse direction, and a first installation cavity 105 for installing a photoelectric detection unit 3 is provided on the top of the detector 101, and a second installation cavity 106 which is connected to the test cavity 104 and is used to install a mirror condensation unit 4 is provided on the top of the thermal seat 102. In this embodiment, the photoelectric detection unit 3 and the mirror condensation unit 4 are prior arts, wherein the photoelectric detection unit includes an emitting end for emitting detection light and a receiving end for receiving reflected light, and the mirror condensation unit 4 includes a lens and a refrigeration stack which are fixed in the second installation cavity 106 in sequence from top to bottom, and a platinum resistance temperature sensor for detecting the lens temperature is embedded in the cold end of the refrigeration stack, and in order to ensure the sealing of the second installation cavity 106, the second installation cavity 106 is filled by a glue sealing method.

[0018] Further preferably, in order to neutralize the heat loss of the heat-conducting housing 2 caused by the heat dissipation of the environment, thereby further maintaining the high temperature difference environment between the test cavity 104 and the dew point value of the measured gas, a second temperature control unit 6 is installed in the heat-conducting seat 102 to heat the heat-conducting seat 102. In this embodiment, the first temperature control unit 5 and the second temperature control unit 6 are each composed of at least two heating tubes and a thermocouple, and the heating tube and the thermocouple are respectively embedded and sealed in the heat-conducting housing 2 / heat-conducting seat 102, and the temperature value fed back by the thermocouple is used to control the on and off of the corresponding heating tube, thereby completing the temperature control operation.

[0019] Further preferably, the heat-conducting shell 2 and the probe body 1 in this embodiment are made of aluminum alloy to ensure the thermal conductivity of the entire shell part, which is beneficial to the heating control of the test cavity 104 environment. In other embodiments, stainless steel can also be used.

[0020] like Figure 3 As shown, in this embodiment, the heat-conducting shell 2 is a cover structure with an opening at the lower end, and the heat-conducting shell 2 has an internal threaded portion 203 at the opening, and the upper end of the heat-conducting seat 102 has an external threaded portion 103 that matches the internal threaded portion 203. The threads of the external threaded portion 103 and the internal threaded portion 203 match to achieve the detachable separation of the heat-conducting shell 2 and the heat-conducting seat 102. The probe body 1 separated from the heat-conducting shell 2 can be used in the detection of normal gas, thereby ensuring the adaptability of the sensor.

[0021] like Figure 2 As shown, the thermal seat 102 is provided with a lower cavity 107, and the lower cavity 107 is provided with a control adapter plate 7 which is electrically connected to the photoelectric detection unit 3, the mirror condensation unit 4 and the second temperature control unit 6 in sequence. Preferably, the detector 101 and the thermal seat 102 are provided with a circuit channel 108 for the corresponding leads of the photoelectric detection unit 3 and the mirror condensation unit 4 to pass through, and the circuit channel 108 is sealed by glue filling; a lower cover for sealing the lower cavity 107 is installed at the bottom of the thermal seat 102, and a direct connector is installed on the lower cover, such as Figure 4 As shown, the control adapter board 7 is communicatively connected to the control system 14 of the dew point meter via the main connector 9; an upper cavity 204 is provided in the heat-conducting housing 2, and a temperature control circuit board 8 electrically connected to the first temperature control unit 5 is provided in the upper cavity 204; an upper cover for sealing the upper cavity 204 is installed on the top of the heat-conducting housing 2, and a first auxiliary connector 10 is installed on the upper cover, and the temperature control circuit board 8 is electrically connected to the first auxiliary connector 10 via a needle electrode. In order to improve the integration of the sensor, a second auxiliary connector 11 is installed on the lower cover, and the second auxiliary connector 11 is electrically connected to the control adapter board 7 via a needle electrode, as shown in FIG. Figure 4As shown, the first auxiliary connector 10 and the second auxiliary connector 11 are communicatively connected via a plug connector, so that the control signals of the first temperature control unit 5 and the second temperature control unit 6 are integrated on a control adapter board 7 .

[0022] like Figure 1 and Figure 4 As shown, in order to avoid premature condensation of the gas to be measured, thereby reducing the water content and affecting the accuracy of the measurement result, one end of the gas inlet 201 is connected to a sampling pipeline, and the outside of the sampling pipeline is wrapped with a heating belt 12. Preferably, the heating belt 12 is electrically connected to the temperature control device 13 so that the temperature of the heating belt 12 is not lower than the temperature of the sampled gas.

[0023] When implementing the above technical solution, the sensor is connected to the control system 14 of the dew point meter through the communication connector, the heating belt 12 is connected to the temperature control device 13, the dew point prediction range of the gas to be measured is 80-90°C, the heating belt 12, the heat-conducting shell 2 and the heat-conducting seat 102 are all heated to 100°C, so that the temperature in the sampling pipeline and the test cavity 104 is higher than the dew point temperature of the gas to be measured by more than 10°C, and the gas to be measured enters the sensor from the air inlet 201 and passes over the mirror surface. At the same time, the temperature of the refrigeration stack of the mirror condensation unit 4 is controlled. When the temperature of the mirror surface is When the temperature is lower than the dew point, condensed water is easily formed due to the very high water content of the high dew point gas, and the test chamber 104 has a temperature difference environment higher than 10°C, so that the formed condensed water evaporates quickly, effectively preventing the condensed water from condensing in the test chamber 104, so that dew is cooled and condensed only on the mirror surface to form a stable dew layer. The control system 14 receives the stable voltage signal fed back from the photoelectric detection unit 3 to determine the equilibrium state of the detection. At this time, the dew point value of the high dew point gas is obtained by the mirror temperature fed back by the platinum resistance temperature sensor, so as to realize the calibration of the sensor in the high dew point range.

Claims

1. A high dew point gas detection sensor, comprising a probe body, a photoelectric detection unit and a mirror condensation unit, wherein the probe body has a test cavity for circulating the gas to be detected, the mirror condensation unit is installed at the bottom of the test cavity, and the photodetection unit is installed at the top of the test cavity, characterized in that: A heat-conducting shell is installed on the probe body outside the test cavity. An air inlet and an air outlet for communicating with the test cavity are opened outside the heat-conducting shell. A first temperature control unit is installed in the heat-conducting shell to heat the heat-conducting shell.

2. A high dew point gas detection sensor according to claim 1, characterized in that: The probe body includes a detector and a thermal conductive seat connected in sequence from top to bottom, the test cavity is arranged in the detector along the horizontal direction, a first installation cavity for installing a photoelectric detection unit is provided on the top of the detector, a second installation cavity connected to the test cavity and for installing a mirror condensation unit is provided on the top of the thermal conductive seat, and a second temperature control unit is installed in the thermal conductive seat to heat the thermal conductive seat.

3. A high dew point gas detection sensor according to claim 1, characterized in that: The heat-conducting shell is a cover structure with an opening at the lower end. The opening of the heat-conducting shell is provided with an internal threaded portion, and the upper end of the heat-conducting seat is provided with an external threaded portion matched with the internal threaded portion.

4. A high dew point gas detection sensor according to claim 2, characterized in that: A lower cavity is provided in the thermal seat, and a control adapter board is provided in the lower cavity, which is electrically connected to the photoelectric detection unit, the mirror condensation unit and the second temperature control unit in sequence. The control adapter board is communicatively connected to the control system of the dew point meter via a main connector installed at the bottom of the thermal seat.

5. A high dew point gas detection sensor according to claim 4, characterized in that: An upper cavity is provided in the heat-conductive shell, a temperature control circuit board electrically connected to the first temperature control unit is provided in the upper cavity, a first auxiliary connector electrically connected to the temperature control circuit board is installed on the heat-conductive shell, a second auxiliary connector electrically connected to the control adapter board is installed at the bottom of the heat-conductive seat, and the first auxiliary connector and the second auxiliary connector are communicatively connected via a plug connector.

6. A high dew point gas detection sensor according to any one of claims 1 to 5, characterized in that: One end of the air inlet is connected to a sample injection pipeline, and the outer side of the sample injection pipeline is wrapped with a heating belt, and the temperature of the heating belt is not lower than the temperature of the injection gas.

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