Dew point temperature measuring device and method

Abstract

The invention discloses a dew-point temperature measuring device and method.The device comprises an electron microscope, an upper computer and a cold mirror type precise dew-point meter, the electron microscope is used for shooting and collecting mirror images of the dew-point meter, and the upper computer is connected with the dew-point meter and the electron microscope; and the control module is used for monitoring the photoelectric signal voltage value and the mirror surface temperature of the dew-point instrument, controlling the electron microscope to shoot and collect the mirror surface image of the dew-point instrument in real time when the photoelectric signal voltage value changes, analyzing the collected mirror surface image, calculating the number of condensates or the density value of the condensates on the mirror surface of the dew-point instrument at the moment, and calculating the temperature of the mirror surface of the dew-point instrument. And if the number of the condensates or the density value of the condensates is greater than a preset value, controlling the dew-point instrument to increase the temperature of the mirror surface, otherwise, controlling the temperature of the mirror surface to be stable and unchanged, and taking the final stable temperature as the dew-point temperature. According to the invention, the state of the mirror surface can be monitored in real time, the fine control of the voltage change value of the photoelectric signal is realized, and the growth state of the condensate on the mirror surface is controlled at the initial growth stage.

Description

Technical Field

[0001] The invention belongs to the technical field of measurement and testing, and in particular relates to a dew point measuring device and method. Background Art

[0002] Dew point temperature is the temperature at which the air reaches saturation through cooling when the amount of water vapor in the air is constant. It is an important physical quantity that reflects the water vapor content in the gas to be measured and is also an important representation of humidity. The chilled mirror precision dew point meter is a widely used measuring device for verifying and calibrating gas humidity measuring instruments.

[0003] Traditional cold mirror precision dew point meters rely on the voltage change of the photoelectric signal to determine when dew is generated on the mirror surface when measuring the dew point. According to the concept of dew point, the dew point temperature can be considered to be the mirror surface temperature when the first dew drops appear near the dew nucleus on the mirror surface. However, since the voltage value of the photoelectric signal is not sensitive to the change of the mirror surface temperature, when the voltage value of the photoelectric signal changes significantly, the dew point temperature measured by the dew point meter through the voltage change is usually lower than the actual dew point temperature, and the dew point temperature cannot be accurately measured. Summary of the invention

[0004] The purpose of the present invention is to address the problem that the photoelectric signal of the existing cold mirror precision dew point meter is insensitive to the change of mirror temperature, and to provide a dew point temperature measurement device and method, which can monitor the mirror state in real time, realize fine control of the voltage change value of the photoelectric signal, and control the growth state of condensation on the mirror surface at the early stage of growth.

[0005] One aspect of the present invention provides a dew point temperature measuring device, comprising an electron microscope, a host computer and a cold mirror type precision dew point meter, the dew point meter is used to measure the dew point temperature of a gas to be measured, and comprises a semiconductor refrigeration piece, a platinum resistor, a gas circuit, a cold mirror, a light source and a detector, the semiconductor refrigeration piece is used to adjust the mirror temperature by heating or cooling, the platinum resistor is used to measure the mirror temperature, the gas circuit is used to pass the gas to be measured, the light source is used to emit light to illuminate the mirror; the detector is used to receive the light reflected by the mirror to obtain a photoelectric signal voltage value;

[0006] The electron microscope is used to shoot and collect the mirror image of the dew point meter. The host computer is connected to the dew point meter and the electron microscope, and is used to monitor the photoelectric signal voltage value and the mirror temperature of the dew point meter. When the photoelectric signal voltage value changes, the electron microscope is controlled to shoot and collect the mirror image of the dew point meter in real time, and the collected mirror image is analyzed to calculate the number of condensates or the condensate density value on the mirror surface of the dew point meter at this time. If the number of condensates or the condensate density value is greater than a predetermined value, the dew point meter is controlled to increase the mirror temperature. If the number of condensates or the condensate density value is not greater than the predetermined value, the mirror temperature is controlled to remain stable, and the final stable temperature is used as the dew point temperature.

[0007] Another aspect of the present invention provides a method for measuring dew point temperature, using the above-mentioned device to measure dew point temperature, the method comprising:

[0008] The gas to be tested is passed into the cold mirror precision dew point meter to start the dew point measurement, and the photoelectric signal voltage value and mirror temperature of the dew point meter are monitored by the host computer;

[0009] When the voltage value of the photoelectric signal changes, the host computer controls the electron microscope to take and collect the mirror image of the dew point meter in real time;

[0010] The host computer analyzes the collected mirror image and calculates the number or density of condensation on the dew point meter mirror at this time. If the number or density of condensation is greater than a preset value, the dew point meter is controlled to increase the mirror temperature. If the number or density of condensation is not greater than a preset value, the mirror temperature is controlled to remain stable and the final stable temperature is used as the dew point temperature.

[0011] Preferably, the host computer analyzes the collected images as follows:

[0012] The collected image is grayed to obtain a grayscale image, and the mirror temperature T when the photoelectric signal changes is recorded. If the mirror temperature T is less than 0°C, the condensation on the mirror is judged to be frost, and then the condensation density is obtained by calculating the ratio of the number of black pixels to the total number of pixels in the grayscale image; if the mirror temperature T is greater than 0°C, the condensation in the image is judged to be dew, and then the obtained grayscale image is binarized and inverted, and then morphological processing is performed after inversion, and then distance transformation and watershed transformation are performed. The transformed images are composited and superimposed to remove adhesion in the image, and finally the number of condensations is counted.

[0013] Preferably, if the number of condensates is greater than a first predetermined value, the dew point meter is controlled to increase the mirror temperature; if the number of condensates is less than or equal to the first predetermined value, the mirror temperature is controlled to remain stable; or, if the density of condensates is greater than a second predetermined value, the dew point meter is controlled to increase the mirror temperature; if the density of condensates is less than or equal to the second predetermined value, the mirror temperature is controlled to remain stable.

[0014] Preferably, the first predetermined value is 100, and the second predetermined value is 0.15.

[0015] According to the dew point temperature measurement device and method of the above aspects of the present invention, the mirror state can be monitored in real time, the photoelectric signal voltage change value can be finely controlled, and the growth state of condensation on the mirror surface can be controlled at the initial growth stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0017] Figure 1 It is a structural schematic diagram of a dew point temperature measuring device according to an embodiment of the present invention;

[0018] Figure 2 is a flow chart of a dew point temperature measurement method according to an embodiment of the present invention;

[0019] Figure 3 It is a flow chart of a mirror image analysis process according to one embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] An embodiment of the present invention provides a dew point temperature measuring device, such as Figure 1 As shown, the dew point temperature measuring device of the embodiment of the present invention includes an electron microscope, a host computer and a cold mirror type precision dew point meter. The electron microscope is used to capture and collect mirror images; the host computer is used to receive the mirror images collected by the electron microscope for analysis and to transmit data with the cold mirror type precision dew point meter; the cold mirror type dew point meter is used for dew point measurement. Figure 1 In the embodiment of the cold mirror type precision dew point meter, an observation window is arranged above the cold mirror surface, and the objective lens of the electron microscope is placed above the observation window for real-time acquisition of the mirror surface image. The cold mirror type precision dew point meter includes a semiconductor refrigeration plate, a platinum resistor, a gas circuit, a cold mirror surface, a light source and a detector. The semiconductor refrigeration plate is used to adjust the mirror surface temperature by heating or cooling; the platinum resistor is used to measure the mirror surface temperature; the gas circuit is a channel through which the gas passes, and is used to pass the gas to be measured; the mirror surface is a platform for dew droplet generation; the light source is used to emit light to illuminate the mirror surface; the detector is used to receive the light reflected by the mirror surface to obtain the voltage value of the photoelectric signal.

[0022] The host computer is connected to the dew point meter and the electron microscope, and is used to monitor the photoelectric signal voltage value and the mirror temperature of the dew point meter. When the photoelectric signal voltage value changes, the electron microscope is controlled to capture and collect the mirror image of the dew point meter in real time, and the collected mirror image is analyzed to calculate the number of condensates or the condensate density value on the mirror of the dew point meter at this time. If the number of condensates or the condensate density value is greater than a predetermined value, the dew point meter is controlled to increase the mirror temperature. If the number of condensates or the condensate density value is not greater than the predetermined value, the mirror temperature is controlled to remain stable, and the final stable temperature is used as the dew point temperature.

[0023] The working process of the dew point temperature measurement device of the embodiment of the present invention is: first, saturated moisture under normal pressure is introduced into the cold mirror precision dew point meter as the measured gas, the temperature of the mirror is controlled by a semiconductor refrigeration plate, and the electron microscope is turned on to collect the mirror image after the voltage value of the photoelectric signal changes in real time. At the same time, the host computer analyzes the collected image, calculates the number or density value of condensation on the mirror, and controls the dew point meter to change the mirror temperature according to the calculated data, controls the change of the photoelectric signal, and controls the growth of the condensation in the early stage.

[0024] The embodiment of the present invention also provides a dew point temperature measurement method, which uses the above-mentioned device to measure the dew point temperature. Figure 2 As shown, the specific steps of the method are: passing the normal pressure saturated gas to be measured into the cold mirror type precision dew point meter, starting the dew point measurement, the host computer monitors the voltage value of the photoelectric signal and the mirror temperature, and when the voltage value of the photoelectric signal changes, the electron microscope is turned on to shoot and collect the mirror image in real time, and the collected image is transmitted to the host computer, and the host computer analyzes the mirror image, calculates the number of condensates or the density of condensates on the mirror surface of the dew point meter at this time, if the number of condensates or the density of condensates is greater than a predetermined value, the dew point meter is controlled to increase the mirror temperature, if the number of condensates or the density of condensates is not greater than the predetermined value, the mirror temperature is controlled to remain stable, and the final stable temperature is used as the dew point temperature.

[0025] In one embodiment, Figure 3 As shown in the figure, the specific process of the upper computer analyzing the mirror image is as follows: first, the collected image is grayed to obtain a gray image, and the mirror temperature T when the photoelectric signal changes is recorded. If the mirror temperature T is less than 0°C, the condensation on the mirror is judged to be frost, and then the condensation density of the image is calculated; if the mirror temperature T is greater than 0°C, the condensation in the image is judged to be dew, and then the obtained gray image is binarized and inverted, and then morphological processing is performed after inversion, and then distance transformation and watershed transformation are performed, the transformed images are composited and superimposed, and the adhesion in the image is removed, and finally the number of condensation is counted and the final result is output.

[0026] The image condensation density is the ratio of the condensation area on the mirror to the total mirror area. In the image processing process, the original image is first converted into a grayscale image. In the grayscale image, condensation such as dew drops or ice crystals appear black, while the part without condensation is white. By calculating the ratio of the number of black pixels to the total number of pixels in the grayscale image, the density of condensation on the mirror can be obtained. The calculation formula is:

[0027]

[0028] In one embodiment, the mirror temperature is controlled by judging whether the number of condensates or the density of condensates is greater than a predetermined value as follows: if the number of condensates is greater than a first predetermined value, the dew point meter is controlled to increase the mirror temperature; if the number of condensates is less than or equal to the first predetermined value, the mirror temperature is controlled to remain stable; or, if the density of condensates is greater than a second predetermined value, the dew point meter is controlled to increase the mirror temperature; if the density of condensates is less than or equal to the second predetermined value, the mirror temperature is controlled to remain stable. Taking the standard gas with a dew point temperature of -20°C as an example, the first predetermined value is 100 and the second predetermined value is 0.15.

[0029] In summary, the dew point temperature measurement device and method of the embodiment of the present invention utilizes an electron microscope to take real-time photographs of the mirror surface of a traditional cold mirror precision dew point meter, records the mirror image from the change in the voltage value of the photoelectric signal to the end of the dew point measurement, and transmits the photographed image to a host computer. The host computer analyzes the image using a mirror image analysis method, clarifies the state of the mirror surface at this time and returns it to the dew point meter. The dew point meter controls the temperature of the mirror surface according to the returned data to avoid the problem that the photoelectric signal is insensitive to changes in the mirror temperature. With the assistance of the image, the voltage change of the photoelectric signal is controlled, and the growth state of the condensate on the mirror surface is controlled at the early stage of growth, thereby improving the accuracy of the dew point temperature measurement.

[0030] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A dew point temperature measuring device, characterized in that: It includes an electron microscope, a host computer and a cold mirror type precision dew point meter. The dew point meter is used to measure the dew point temperature of the gas to be measured, and includes a semiconductor refrigeration piece, a platinum resistor, a gas circuit, a cold mirror, a light source and a detector. The semiconductor refrigeration piece is used to adjust the mirror temperature by heating or cooling. The platinum resistor is used to measure the mirror temperature. The gas circuit is used to pass the gas to be measured. The light source is used to emit light to illuminate the mirror. The detector is used to receive the light reflected by the mirror to obtain the voltage value of the photoelectric signal. The electron microscope is used to shoot and collect the mirror image of the dew point meter. The host computer is connected to the dew point meter and the electron microscope, and is used to monitor the photoelectric signal voltage value and the mirror temperature of the dew point meter. When the photoelectric signal voltage value changes, the electron microscope is controlled to shoot and collect the mirror image of the dew point meter in real time, and the collected mirror image is analyzed to calculate the number of condensates or the condensate density value on the mirror surface of the dew point meter at this time. If the number of condensates or the condensate density value is greater than a predetermined value, the dew point meter is controlled to increase the mirror temperature. If the number of condensates or the condensate density value is not greater than the predetermined value, the mirror temperature is controlled to remain stable, and the final stable temperature is used as the dew point temperature.

2. A dew point temperature measurement method, characterized in that: Dew point temperature measurement is performed using the device according to claim 1, the method comprising: The gas to be tested is passed into the cold mirror precision dew point meter to start the dew point measurement, and the photoelectric signal voltage value and mirror temperature of the dew point meter are monitored by the host computer; When the voltage value of the photoelectric signal changes, the host computer controls the electron microscope to take and collect the mirror image of the dew point meter in real time; The host computer analyzes the collected mirror image and calculates the number or density of condensation on the dew point meter mirror at this time. If the number or density of condensation is greater than a preset value, the dew point meter is controlled to increase the mirror temperature. If the number or density of condensation is not greater than a preset value, the mirror temperature is controlled to remain stable and the final stable temperature is used as the dew point temperature.

3. The method according to claim 2, characterized in that The host computer analyzes the collected images as follows: The collected image is grayed to obtain a grayscale image, and the mirror temperature T when the photoelectric signal changes is recorded. If the mirror temperature T<0℃, the condensation on the mirror is judged to be frost, and then the condensation density is obtained by calculating the ratio of the number of black pixels to the total number of pixels in the grayscale image; if the mirror temperature T>0℃, the condensation in the image is judged to be dew, and then the obtained grayscale image is binarized and inverted, and then morphological processing is performed after inversion, and then distance transformation and watershed transformation are performed. The transformed images are composited and superimposed to remove adhesion in the image, and finally the number of condensations is counted.

4. The method according to claim 3, characterized in that If the number of condensates is greater than the first predetermined value, the dew point meter is controlled to increase the mirror temperature; if the number of condensates is less than or equal to the first predetermined value, the mirror temperature is controlled to remain stable; or, if the density of condensates is greater than the second predetermined value, the dew point meter is controlled to increase the mirror temperature; if the density of condensates is less than or equal to the second predetermined value, the mirror temperature is controlled to remain stable.

5. The method according to claim 4, characterized in that The first predetermined value is 100, and the second predetermined value is 0.15.

Images