CN202049124U - Dew point measuring instrument for low-humidity gas - Google Patents
Dew point measuring instrument for low-humidity gas Download PDFInfo
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- CN202049124U CN202049124U CN2011200372097U CN201120037209U CN202049124U CN 202049124 U CN202049124 U CN 202049124U CN 2011200372097 U CN2011200372097 U CN 2011200372097U CN 201120037209 U CN201120037209 U CN 201120037209U CN 202049124 U CN202049124 U CN 202049124U
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- dew point
- temperature
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Abstract
The utility model provides a dew point measuring instrument for low-humidity gas, comprising a chilled mirror chamber, a refrigerating circuit, a photoelectric measuring circuit, a temperature measuring circuit, a controller and an input/output unit, wherein the controller judges a dew point in advance by the time when the change of the energy of reflected/dispersed light of a mirror surface exceeds a set value; the temperature of the mirror surface can quickly approach to the temperature by adjusting the refrigerating voltage; when the adjusting amplitude of the temperature is less than the preset value, the energy of the reflected/dispersed light can achieve the preset value and the change quantity trends to be zero, so that the mirror surface temperature at the moment is judged as the dew point of the detected gas. The dew point measuring instrument can quickly and exactly measure the dew point of the low-humidity gas.
Description
Technical field
The utility model relates to a kind of device that utilizes the minute surface principle to measure gas dew point, is particularly suitable for the rapid and accurate determination to the low humidity gas dew point.
Background technology
The principle that chilled-mirror type dew point instrument is measured dew point is: a branch of illumination is mapped on the polishing minute surface of temperature controllable, accepts its reflected light by the photoelectric sensor receiving tube.When minute surface was dry, its reflected light maximum was promptly launched light and is stood up fully and received by the photoelectric sensor receiving tube.The sample air-flow is through the condensation mirror of dew point Cold Mirrors chamber, by the equipressure refrigeration, makes the sample gas dewfall state that reaches capacity.When condensate water on the minute surface was divided into the frost layer, emission light was scattered, thereby the intensity of reflected light of accepting weakens.This received signal is relatively amplified after processor is sent in the A/D conversion, the refrigeration electric current of refrigeration pump is controlled in the back as calculated, thereby control mirror temperature and make minute surface remain on uniform temperature, this moment, minute surface frost layer kept certain thickness, when keeping this thickness frost layer, the energy of reflection light that the photoelectric sensor receiving tube receives loses to desired value, be that water vapor in the gas is condensed into frost and reaches relative balance state on minute surface, keeping frost layer is a specific thicknesses, this moment minute surface temperature by temperature sensor measurement and be recorded as the dew point of tested gas.
The major advantage that the chilled-mirror type dew point is measured is the precision height, especially after adopting semiconductor refrigerating and photoelectric detecting technology, and uncertainty even can reach 0.1 ℃; Maximum shortcoming is that response speed is slower, especially when detecting the dew point of low humidity gas, equilibration time even reach several hrs, and the method requires also higherly to the spatter property of sample gas and corrosivity, otherwise can influence the Photoelectric Detection effect or generation ' pseudo-dewfall ' causes measuring error.
At the slow problem of low humidity gas dew point finding speed, United States Patent (USP) (US5139344) shortens equilibration time by the auxiliary humidification device to low humid gas auxiliary humidification, and minute can foreshorten to 10-15 minute like this.Yet for unknown gas since humidification amount and add wet point and be difficult to accurate control cause system oscillation easily, thereby prolong stabilization time.Chinese invention patent (CN101236166B) shortens equilibration time by the improvement of control method.Promptly in the dew process that disappears, the corresponding electric current of different interval setting according to luminous energy deviation and luminous energy deviation variation rate is adjusted step-length, and the current value that equals this step-length by adding deduct on current refrigeration electric current is adjusted the size of refrigeration electric current, the control mirror temperature is with the control frost thickness, make it to approach gradually specific thicknesses, thereby eliminate unbalance of system and the vibration that occurs.
Existing chilled-mirror type dew point instrument is controlled mirror temperature after all being the abundant frosting of the moisture in making gas to be measured, eliminates too much frosting and makes frost thickness reach setting value, measures dew point.Yet the formation of minute surface frost layer has certain hysteresis quality with respect to cold pump cold junction temperature.When frost layer is blocked up, can cause cold pump outage, cold junction temperature raises fast, and is very dry by the gas of minute surface, and the speed that hydrone condenses at minute surface is less than the speed of escaping, and the frost layer is with attenuation; Recover rapidly though be about to reach specific frost thickness electric current,, cause frost thickness to become thin even disappearance because of mirror temperature can not reduce rapidly.The rapid pressure of cold pump startup this moment is cold, and minute surface condenses into frost rapidly, causes the frosting layer blocked up, goes round and begins again.Therefore, minute surface reach specific frost thickness often need be through the dynamic adjustment process of long period.For under hot environment, because cold pump hot junction thermal accumlation, the heat radiation difficulty descends between the cold pump refrigerating capacity, sometimes even be difficult to make cold junction to freeze once more to the temperature that is lower than dew point, causes dew point to be difficult to maybe can't finish measurement.
Therefore how to realize rapidly and accurately that the mensuration of the dew point of different moisture levels gas becomes the difficult problem that industry needs to be resolved hurrily.
The utility model content
The utility model provides a kind of low humidity gas dew point measuring instrument, and the control system of existing dew point hygrometer has been done very big improvement, has improved speed and accuracy that the low humidity gas dew point is measured.
The utility model provides low humidity gas dew point measuring instrument, comprises Cold Mirrors chamber, refrigeration circuit, photoelectric measurement circuit, temperature measuring circuit, controller and input-output unit; Wherein Cold Mirrors is indoor light emitting diode, photodiode, refrigeration unit, mirror surface and a platinum resistance temperature sensor; The indoor light emitting diode of photoelectric measurement circuit and Cold Mirrors is connected with photodiode, the indoor refrigeration unit of refrigeration circuit and Cold Mirrors is connected, temperature measuring circuit is connected with platinum resistance temperature sensor, the co-ordination of controller control refrigeration circuit, photoelectric measurement circuit, temperature measuring circuit.In the dew point measuring process, controller is regulated the refrigeration voltage of refrigeration circuit, by refrigeration unit mirror surface is carried out fast-refrigerating, monitors the anti-/ scattered energy of minute surface simultaneously in real time by the photoelectric measurement circuit, calculates the poor Δ R with initial value; When Δ R surpassed a certain setting value, temperature measuring circuit was measured the mirror temperature T of this moment
1, as the anticipation dew point, the photoelectric measurement circuit measuring is anti-/ scattered energy R at this moment with it for controller
1, controller is setting value of anti-/ scattered energy during as dew point with it; Controller is according to formula K1 * (R
1-R
x)+K2 * (T
1-T
x) calculate and the voltage of adjustment refrigeration rapidly, make variation of temperature amount Δ T less than setting value; Suitably adjust the refrigerating capacity of cooling piece then, the anti-/ scattered energy variable quantity before and after control is adjusted levels off to zero, and anti-/ scattered energy reaches setting value R
1, the mirror temperature that this moment, temperature measuring circuit was measured is exactly the dewpoint temperature of gas to be measured.
The low humidity gas dew point measuring instrument that the utility model provides, owing to adopted the judgement of in the process of dewfall, carrying out dew point, when having solved other dew point hygrometer and having measured low humidity gas because hypohydration, frost thickness can not reach the difficult problem that specific thicknesses causes measurement not finish, and has avoided the system oscillation in the auxiliary humidification method mensuration process.Even more important the utility model is to measure dew point in the dewfall process, but not measures in the dew process that disappears after abundant dewfall.So just can shorten the time greatly, and not have the auxiliary humidification device, reduce the complexity of system, help improving the stability and the degree of accuracy of control.
Description of drawings
The mirror surface type dew point hygrometer structural representation block diagram that Fig. 1 provides for the utility model
Fig. 2 is the utility model control flow chart
Fig. 3 for the utility model with common and have a waveform synoptic diagram in dew point hygrometer when mensuration of auxiliary humidification function
Fig. 4 is the improper ground damped oscillation waveform synoptic diagram that caused of humidification
Embodiment
Further specify embodiment of the present utility model below in conjunction with accompanying drawing and instantiation.Those skilled in the art can understand feature and advantage of the present utility model by the content that this explanation disclosed.The utility model also can be implemented and used by other different instantiation.
The utility model provides a kind of chilled-mirror type dew point instrument of fast measuring low humidity gas dew point, and its structural representation as shown in Figure 1.It comprises Cold Mirrors chamber, refrigeration circuit, photoelectric measurement circuit, temperature measuring circuit, controller and input-output unit.Wherein the Cold Mirrors chamber comprises photoelectric monitor unit, platinum resistance 4 and the refrigeration unit of being made up of light emitting diode 1, photodiode 2 and minute surface 35; Metering circuit is made up of photoelectric detective circuit 6, temperature measurement circuit 7 and refrigeration circuit 8, is connected with photoelectric monitor unit, platinum resistance 4 and the refrigeration unit 5 of Cold Mirrors chamber respectively; Controller 9 is connected with photoelectric detective circuit 6, temperature measurement circuit 7 and refrigeration circuit 8, coordinates their work; Input-output unit comprises operation push-button 10, LCDs 11 and usb 12.In the measuring process, light emitting diode emission light, photodiode receives the light of direct reflection or scattering, and refrigeration unit freezes to minute surface.When detected gas is skimmed over cold minute surface, on minute surface, form the frost layer.Controller is by the real-time catoptrical energy of monitoring of observation circuit, when catoptrical energy difference surpasses a certain setting value, thinks to have begun dewfall on the minute surface, and the mirror temperature of record this moment is with its dew point as anticipation; Control system is in time adjusted refrigeration voltage, makes mirror temperature near the anticipation dewpoint temperature.When the fluctuation of temperature is spent less than 0.2, can be defined as the dew point of tested gas.
Fig. 2 illustrates the schematic flow sheet that the utility model is measured the low humidity gas dew point.After beginning to measure, refrigeration system is to the quick forced refrigeration of minute surface, and controller writes down the initial value R of anti-/ scattered energy by photoelectric monitoring system
0, and monitor anti-/ scattered energy R of minute surface in real time
x, calculate their difference DELTA R, as Δ R during, proceed forced refrigeration less than setting value; And when Δ R surpasses a certain setting value, can judge rapid dewfall on the minute surface, this moment, mirror temperature was suitable with actual dew point value to be measured, can judge that also gas humidity to be measured is lower than the temperature of this point, control system record mirror temperature T at this moment
1Instead/scattered energy R
1In the tradition dew-point measuring method, reduce mirror temperature, reach setting value up to the cut-layer thickness of minute surface, when the humidity of gas was low, the content * time of thickness increment ≈ moisture was so the classic method timing is longer.
Enter the accurate mensuration stage of dew point subsequently.According to the dewpoint temperature of anticipation, adjust refrigeration voltage, adjusting range is by K1 * (R
1-R
x)+K2 * (T
1-T
x) calculate, wherein K1 and K2 are constant.When Δ T (is T
1-T
x) when spending, can judge the true dew point of the approaching tested gas of measured value this moment less than 0.2.Suitably adjust the refrigerating capacity (mirror temperature) of cooling piece then, the anti-/ scattered energy changes delta R before and after control is adjusted levels off to zero, and anti-/ scattered energy reaches setting value R
1, this moment, the dewfall speed of minute surface was basic identical with the dew speed that disappears, and the temperature of minute surface is the dew point of tested gas.
Horizontal ordinate is the time among Fig. 3 and Fig. 4, and ordinate is a mirror temperature, and the difference of the utility model and other dew point hygrometer mirror temperature change curve when measuring the low humidity gas dew point is shown.Other dew point hygrometer mirror temperature all needs a plurality of vibration adjustment processes just can reach the actual dew point of tested gas.When measuring the low humidity gas dew point, utilize auxiliary humidification can shorten the cycle that vibration is adjusted, yet, improper if humidification amount and humidification time point are grasped, damped oscillation as shown in Figure 4 can be caused again, and measuring process can not be finished.And the low humidity gas dew point measuring instrument that utilizes the utility model to provide is measured the vibration adjustment process that does not have temperature in the dew point process basically.Therefore minute can be shortened greatly, also measurement result exactly can be obtained fast for low humidity gas.
Claims (1)
1. a low humidity gas dew point measuring instrument comprises Cold Mirrors chamber, refrigeration circuit, photoelectric measurement circuit, temperature measuring circuit, controller and input-output unit; It is characterized in that described Cold Mirrors is indoor has light emitting diode, photodiode, refrigeration unit, mirror surface and a platinum resistance temperature sensor; The indoor light emitting diode of described photoelectric measurement circuit and Cold Mirrors is connected with photodiode, and the indoor refrigeration unit of described refrigeration circuit and Cold Mirrors is connected, and described temperature measuring circuit is connected with platinum resistance temperature sensor; The co-ordination of described controller control refrigeration circuit, photoelectric measurement circuit and temperature measuring circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200372097U CN202049124U (en) | 2011-02-12 | 2011-02-12 | Dew point measuring instrument for low-humidity gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200372097U CN202049124U (en) | 2011-02-12 | 2011-02-12 | Dew point measuring instrument for low-humidity gas |
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| Publication Number | Publication Date |
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| CN202049124U true CN202049124U (en) | 2011-11-23 |
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| CN2011200372097U Expired - Fee Related CN202049124U (en) | 2011-02-12 | 2011-02-12 | Dew point measuring instrument for low-humidity gas |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103018207A (en) * | 2012-10-18 | 2013-04-03 | 常州鸿源动力科技有限公司 | Chilled-mirror dew-point hygrometer based on Stirling low temperature refrigerator |
| CN105987930A (en) * | 2016-07-06 | 2016-10-05 | 中国人民解放军空军勤务学院 | Self-cooling type dew-point instrument |
| CN109073578A (en) * | 2016-02-25 | 2018-12-21 | ams有限公司 | Cmos compatible dew point transducer device and the method for determining dew point |
| CN109085201A (en) * | 2018-09-12 | 2018-12-25 | 南京信息工程大学 | A kind of ultra-low humidity dew point hygrometer and its temprature control method |
| CN110596189A (en) * | 2019-09-10 | 2019-12-20 | 深圳国技仪器有限公司 | Humidity detection method and device under high-temperature, high-humidity, high-dust and high-corrosion environment |
-
2011
- 2011-02-12 CN CN2011200372097U patent/CN202049124U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103018207A (en) * | 2012-10-18 | 2013-04-03 | 常州鸿源动力科技有限公司 | Chilled-mirror dew-point hygrometer based on Stirling low temperature refrigerator |
| CN109073578A (en) * | 2016-02-25 | 2018-12-21 | ams有限公司 | Cmos compatible dew point transducer device and the method for determining dew point |
| US11002696B2 (en) | 2016-02-25 | 2021-05-11 | Sciosense B.V. | CMOS-compatible dew point sensor device and method of determining a dew point |
| US11525793B2 (en) | 2016-02-25 | 2022-12-13 | Sciosense B.V. | CMOS compatible dew point sensor device and method of determining a dew point |
| CN105987930A (en) * | 2016-07-06 | 2016-10-05 | 中国人民解放军空军勤务学院 | Self-cooling type dew-point instrument |
| CN109085201A (en) * | 2018-09-12 | 2018-12-25 | 南京信息工程大学 | A kind of ultra-low humidity dew point hygrometer and its temprature control method |
| CN109085201B (en) * | 2018-09-12 | 2023-09-15 | 南京信息工程大学 | Ultralow humidity dew point meter and temperature control method thereof |
| CN110596189A (en) * | 2019-09-10 | 2019-12-20 | 深圳国技仪器有限公司 | Humidity detection method and device under high-temperature, high-humidity, high-dust and high-corrosion environment |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP02 | Change in the address of a patent holder |
Address after: 101102, Tongzhou District Jinqiao technology industry base, Beijing, 13 South four street, 2DF3A Patentee after: Beijing Sintai Xuecheng Instruments Co., Ltd. Address before: 100016, 501, Chaoyang District Road, Jiuxianqiao, Beijing, Kim Tae Lida, room four Patentee before: Beijing Sintai Xuecheng Instruments Co., Ltd. |
|
| DD01 | Delivery of document by public notice |
Addressee: Beijing Sintai Xuecheng Instruments Co., Ltd. Zhang Xiao Document name: Notification of Passing Examination on Formalities |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20111123 Termination date: 20180212 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |