CN204314220U - For the device of optical dissolved oxygen sensor high-precision calibrating - Google Patents
For the device of optical dissolved oxygen sensor high-precision calibrating Download PDFInfo
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- CN204314220U CN204314220U CN201420818735.0U CN201420818735U CN204314220U CN 204314220 U CN204314220 U CN 204314220U CN 201420818735 U CN201420818735 U CN 201420818735U CN 204314220 U CN204314220 U CN 204314220U
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Abstract
The utility model relates to dissolved gas transducer calibration technical field in water, aims to provide a kind of device for optical dissolved oxygen sensor high-precision calibrating.This device comprises welding bottle, carrier gas bottle, water-gas mixer; Stirrer and air-blowing sandspit are established in water-gas mixer inside, and are placed in water-bath; Filled with water in water-gas mixer, reference dissolved oxygen sensor and dissolved oxygen sensor to be calibrated immerse in water from its top drilling; Welding bottle and carrier gas bottle are connected to air-blowing sandspit through reduction valve, gas meter, gas access successively respectively by pipeline.The utility model uses the device of minute quantity to provide unlimited demarcation concentration and selects, and can arrange more calibration point more neatly; Reference value precision has great lifting, can guarantee that calibration result has wider temperature applicable range than existing method.
Description
Technical field
The utility model relates to dissolved gas transducer calibration technical field in water, especially relates to a kind of device for optical dissolved oxygen sensor high-precision calibrating.
Background technology
The existence of Dissolved Oxygen in Water on organism in water has vital impact, and in rapid and accurate determination water body, the content of dissolved oxygen DO is significant.In recent years along with scientific-technical progress, dissolved oxygen DO home position sensing determination techniques obtains fast development.Optical dissolved oxygen sensor based on principle of fluorescent quenching has higher stability, the undisturbed long-time continuous in-situ monitoring that classic method cannot complete can be realized, greatly improve the mensuration means of dissolved oxygen DO in the water bodys such as rivers, lake, ocean, be widely applied in fields such as aquatic products, mining industry, ocean research.
Although optical dissolved oxygen sensor has better stability than other dissolved oxygen sensors, also can there is data wander in Long-Time Service process in the wild in it, therefore need regularly to carry out transducer calibration.Current dissolved oxygen sensor takes two-point method to demarcate more.The method is by the reading of determination sensor under sodium sulfite solution (oxygen-free water) and a certain temperature in the aqueous solution (saturated dissolved oxygen solution) of long-time air aeration, oxygen in water theoretical value at itself and this temperature is carried out two point Linear contrasts, thus demarcates dissolved oxygen sensor.There is the shortcomings such as nominal data point is few, demarcation temperature accuracy is low, reference value accuracy is low in the method.
From the principle of work of Fluorimetric Quenching Method dissolved oxygen sensor, the type sensor mensuration temperature influence remarkable, to the type sensor demarcate must ensure to demarcate environment temperature accurately and stable.Therefore, set up a kind of based on sensor signal value, the optical dissolved oxygen sensor scaling method of internal relation between temperature value and reference value, contribute to the multiple spot high-precision calibrating realizing optical dissolved oxygen sensor, guarantee that sensor provides quality data for scientific research investigative action.
Utility model content
The technical problems to be solved in the utility model is, overcome the shortcomings such as existing dissolved oxygen sensor scaling method calibration point is few, standard value is accurate not, calibration result restricted application, a kind of caliberating device based on temperature and dissolved oxygen control device is provided, utilizes this device that calibrated sensor result can be enable in larger dissolved oxygen concentration with ambient temperature range to keep highly consistent with standard value.
In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is:
Provide a kind of device for optical dissolved oxygen sensor high-precision calibrating, comprise dissolved oxygen sensor to be calibrated; This device also comprises: the water-bath of welding bottle, carrier gas bottle, water-gas mixer, band water temperature control device, water-gas mixer, two gas meters, reference dissolved oxygen sensor and stirrers; Water-gas mixer is airtight container shape, and stirrer and air-blowing sandspit are established in its inside, and water-gas mixer entirety is placed in water-bath; Filled with water in water-gas mixer, reference dissolved oxygen sensor and dissolved oxygen sensor to be calibrated immerse in water from its top drilling; Water-gas mixer is provided with gas access and gas vent, and gas access is simultaneously as iodimetric titration sample tap; Welding bottle and carrier gas bottle are connected to air-blowing sandspit through reduction valve, gas meter, gas access successively respectively by pipeline.
Improve as one, the cylindrical staving of described water-gas mixer.
Device described in the utility model is used for optical dissolved oxygen sensor high precision timestamp, specifically comprises the following steps:
(1) water-gas mixer is placed in water-bath, the setting value of the water temperature control device of water-bath is the some numerical value in 10 DEG C, 15 DEG C, 20 DEG C, 25 DEG C, 30 DEG C;
(2) regulate the gas flow ratio of welding bottle and carrier gas bottle, successively the mixed gas of different oxygen is passed into water-gas mixer, make the water body in airtight container obtain 10 dissolved oxygen concentration gradients successively;
(3) each dissolved oxygen concentration gradient reach stable after, record the signal value of dissolved oxygen sensor to be calibrated and the temperature value of water body respectively, and water sampling is with iodometric determination dissolved oxygen DO standard value;
(4) setting value of water temperature control device is changed to other four temperature values successively, repeat step (2), (3);
(5) according to the signal value of dissolved oxygen sensor to be calibrated of calibration process record, the temperature value of water body and dissolved oxygen DO standard value, the calibration coefficient of dissolved oxygen sensor to be calibrated is calculated; Concrete grammar is:
<1>, according to the temperature value of the sensor signal value obtained under different dissolved oxygen gradient during each desired temperature, water body and dissolved oxygen DO standard value, obtains fitting formula:
In formula, DO is dissolved oxygen DO standard value in water body, and unit is μM; A is temperature coefficient, and X is sensor signal value, label when i is different set temperature;
Temperature coefficient A corresponding under obtaining five temperature by this fitting formula
0, A
1, A
2, A
3, A
4, A
5;
Temperature coefficient A in <2> formula 1 and meet following relation between the temperature value t of water body, calibration coefficient B:
In formula, the unit of temperature t is DEG C, sets up six linear simultaneous equations according to this formula;
<3> solves the calibration coefficient B that six linear simultaneous equations can obtain sensor
00, B
01, B
02, B
03... B
51, B
52, B
53, B
54.
In described step (2), 10 dissolved oxygen concentration gradients of water body refer to, in water body, saturation dissolved oxygen is by 10 dissolved oxygen concentration gradients of 0 to 120% average decile.
In described step (2), be use reference sensor reading to monitor Dissolved Oxygen in Water concentration, stop passing into mixed gas after reaching default dissolved oxygen concentration gradient, and make water-gas mixer remain on sealing state.
The scope of five set temperature value of step (1) should be able to covering sensor practical service environment temperature, is usually set within the scope of 10 ~ 30 DEG C.As comparatively special in sensor environment for use temperature, also adjustable five temperature value setting ranges are to ensure stated accuracy.
In step (2), 10 dissolved oxygen concentration gradients should be evenly distributed within the scope of 0 ~ 120% saturation dissolved oxygen as far as possible, by regulating the oxygen content in oxygen and carrier gas input ratio control mixed gas, make the interval that dissolved oxygen concentration in water body reaches default, without the need to precisely controlling the flow ratio of oxygen and carrier gas, but this Ratio invariableness should be kept in the venting process of same gradient.
Water-gas mixer is cylindrical body, and the material good by heat conductivility is made; Reserved gas access and gas vent at bucket wall, the former is simultaneously as iodimetric titration sample tap, and the latter is when air-blowing as gas vent, and air-blowing terminates rear closedown; In container, settle stirrer to be used for water body stir; Top cover is installed reference dissolved oxygen sensor and dissolved oxygen sensor to be calibrated simultaneously, and the former is for monitoring Dissolved Oxygen in Water fluctuation situation, and measured value need not be accurate; As far as possible by container content full water during test.Water temperature in water-gas mixer is accurately controlled by the water temperature control device of water-bath, and water-bath possesses heating and refrigerating function simultaneously.
Compared with prior art, the beneficial effects of the utility model are:
The utility model controls the dissolved oxygen concentration in caliberating device by adjustment oxygen and carrier gas flux ratio, only need two gas cylinders can build the water body environment of any saturation dissolved oxygen, compared with adopting oxygen generator, mixing the existing methods such as gas cylinder, the utility model uses the device of minute quantity to provide unlimited demarcation concentration and selects, and can arrange more calibration point more neatly; The utility model adopts the iodimetric titration measured value after synchronized sampling as standard value, compared with the existing method such as Calculation of Solubility Dissolved Oxygen in Water concentration, reference value precision has had great lifting with according to mixed gas oxygen concentration in water; The utility model uses five temperature to carry out transducer calibration, can guarantee calibration result than generally adopting the existing method of single temperature spot to have wider temperature applicable range.
Accompanying drawing explanation
Fig. 1 is that dissolved oxygen sensor calibration result and two-point method calibration result contrast.
Fig. 2 is the utility model caliberating device overall schematic.
Fig. 3 is the schematic diagram of water-gas mixer in Fig. 2.
Embodiment
Below in conjunction with Figure of description and instantiation, the utility model is described in further detail.
As shown in Figures 2 and 3, the caliberating device of optical dissolved oxygen sensor in the utility model, comprises water-gas mixer 1, the water-bath 2 of band water temperature control device, gas meter 3, gas meter 4, welding bottle 5, carrier gas bottle 6 (carrier gas of in-built inertia), reference dissolved oxygen sensor a, dissolved oxygen sensor b to be calibrated and stirrer c.
Wherein, water-gas mixer 1 is cylindrical body, and the material good by heat conductivility is made; Reserved gas access e and gas vent g at bucket wall, the former connects air-blowing sandspit d and improves gas-vapor mix efficiency for increasing bubble, and the latter is when air-blowing as gas vent, and air-blowing terminates rear closedown, and gas access e is simultaneously as iodimetric titration sample tap f; In container, settle stirrer c to stir for water body; Top cover is installed reference dissolved oxygen sensor a and dissolved oxygen sensor b to be calibrated simultaneously, and the former is for monitoring Dissolved Oxygen in Water concentration; As far as possible by container content full water during test, and water-gas mixer entirety is placed in water temperature control device 2, is controlled the water temperature in container by water temperature control device 2.
Use Norway AADI 4330F dissolved oxygen sensor (sequence number 795 below, dispatch from the factory in January, 2012 nominal time, accuracy 8 μm of ol/L or 5%) be example, the scaling method of the optical dissolved oxygen sensor in the utility model is described further, specifically comprises the following steps:
Step (1), is set in first temperature value 10 DEG C by water temperature control device, wait for that in water-gas mixer, temperature reaches stable;
Step (2), control to pass into two kinds of gas flow ratios of water-gas mixer by the gas meter 3,4 being connected to welding bottle and carrier gas bottle, make water body wherein form saturation dissolved oxygen successively and be about 10 dissolved oxygen concentration gradients such as 0,10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 100%, 120%;
Step (3), under each dissolved oxygen concentration gradient, the continuous-reading of reference dissolved oxygen sensor a is used to monitor dissolved oxygen concentration in water body, stop passing into mixed gas when its measured value reaches stable and confining gas outlet g, average after the signal value of continuous record 5 groups dissolved oxygen sensor b to be calibrated and temperature value, use iodimetric titration Accurate Measurement dissolved oxygen concentration by water sampling mouth f water sampling, and be defined as standard value;
Step (4), the temperature value setting gradually water temperature control device is 15 DEG C, 20 DEG C, 25 DEG C and 30 DEG C, repeats step (2) and step (3);
Step (5), according to the dissolved oxygen sensor signal value to be calibrated recorded, temperature value and dissolved oxygen DO standard value, calculates the calibration coefficient of dissolved oxygen sensor to be calibrated.The step of calculating sensor calibration coefficient is as follows:
(1) according to sensor signal value, temperature value and standard value that different dissolved oxygen gradient at each temperature obtains, fitting formula is obtained:
In formula, DO is dissolved oxygen concentration in water body, and unit is μM; X is instrument signal value, temperature coefficient A corresponding under obtaining five temperature by this fitting formula
0, A
1, A
2, A
3, A
4, A
5, in table 1;
(2) following relation is met between the temperature coefficient A in formula 1 and temperature t, calibration coefficient B:
In formula, temperature t unit is DEG C, can set up six linear simultaneous equations according to this formula;
(3) the calibration coefficient B that six linear simultaneous equations can obtain sensor is solved
00, B
01, B
02, B
03... B
51, B
52, B
53, B
54, in table 2.
Table 1 dissolved oxygen sensor temperature coefficient
| Temperature | A 0 | A 1 | A 2 | A 3 | A 4 | A 5 |
| 10℃ | 8.15782E+03 | -7.86166E+02 | 3.23201E+01 | -6.83173E-01 | 7.29021E-03 | -3.11692E-05 |
| 15℃ | 5.97060E+03 | -5.79483E+02 | 2.43052E+01 | -5.26269E-01 | 5.74941E-03 | -2.51090E-05 |
| 20℃ | 4.07272E+03 | -3.70333E+02 | 1.48105E+01 | -3.10952E-01 | 3.33854E-03 | -1.44853E-05 |
| 25℃ | 3.47317E+03 | -3.18008E+02 | 1.28153E+01 | -2.71585E-01 | 2.95110E-03 | -1.29960E-05 |
| 30℃ | 3.03179E+03 | -2.74508E+02 | 1.07871E+01 | -2.20342E-01 | 2.28969E-03 | -9.61035E-06 |
Table 2 dissolved oxygen sensor calibration coefficient
| B i0 | B i1 | B i2 | B i3 | B i4 | |
| B 0i | -1.62634E+03 | 3.10234E+03 | -3.12626E+02 | 1.14731E+01 | -1.44216E-01 |
| B 1i | 1.01264E+03 | -4.98669E+02 | 4.63941E+01 | -1.65781E+00 | 2.05903E-02 |
| B 2i | -7.61221E+01 | 2.84187E+01 | -2.54248E+00 | 8.95572E-02 | -1.10545E-03 |
| B 3i | 2.26449E+00 | -7.50136E-01 | 6.56642E-02 | -2.29489E-03 | -2.29489E-03 |
| B 4i | -3.02145E-02 | 9.38246E-03 | -8.10749E-04 | 2.82206E-05 | -3.47205E-07 |
| B 5i | 1.50902E-04 | -4.50707E-05 | 3.86422E-06 | -1.34284E-07 | 1.65357E-09 |
When calibrated optical dissolved oxygen sensor measures under arbitrary temp and dissolved oxygen concentration in calibration range, only need signal value and temperature value that calibration coefficient can be used to calculate the DO determination value of sensor by formula 2 and formula 1, itself and iodimetric titration measured value are carried out contrasting the error that can draw calibration result.As can be seen from temperature and dissolved oxygen concentration accidental validation result (table 3), significantly improve through the accuracy of this method calibrated dissolved oxygen sensor measured value; Carry out contrasting rear discovery with 20 DEG C of two points correction results, this method is significantly better than 2 calibrated measurement results (Fig. 1).
Table 3 dissolved oxygen sensor calibration result accidental validation
| Sequence number | Water temperature | Measured value before transducer calibration | Measured value after transducer calibration | Iodimetric titration measured value | Error after demarcating |
| 1 | 20.71 | 110.06 | 129.37 | 131.69 | -2.32 |
| 2 | 18.06 | 257.82 | 278.47 | 278.05 | 0.42 |
| 3 | 16.84 | 205.59 | 229.43 | 226.95 | 2.48 |
| 4 | 15.84 | 282.86 | 303.46 | 304.36 | -0.90 |
| 5 | 15.52 | 118.32 | 142.31 | 144.17 | -1.86 |
| 6 | 14.36 | 180.68 | 205.55 | 202.84 | 2.71 |
| 7 | 10.41 | 101.27 | 121.81 | 122.34 | -0.53 |
| 8 | 10.11 | 318.39 | 343.04 | 344.63 | -1.59 |
| 9 | 6.02 | 67.21 | 80.85 | 79.61 | 1.24 |
| 10 | 5.90 | 9.64 | 15.02 | 17.07 | -2.05 |
Remarks: Biao Zhong water temperature unit is DEG C, dissolved oxygen DO unit is μM.
With application number for compared with trace quantity dissolved oxygen instrument assay calibration system described in the Chinese patent of CN200710301409 and calibration steps (hereinafter referred to as existing trace quantity dissolved oxygen instrument calibration system) thereof, the utility model has mainly had remarkable improvement in device simplification: existing trace quantity dissolved oxygen instrument calibration system includes water replanishing device (containing small pump, fabric filter, granular activated carbon filter, sintering activity carbon filter and reverse osmosis membrane assembly), gas and water separator (gassy water separation vessel and tertiary effluent envelope device), micro amount of oxygen water disposal facility is (containing water tank, ebullator, current regulator, deoxygenation filtrator, ion exchange resin, faraday's electrolytic cell, Inlet and outlet water ball valve, short circuit pipe and flowmeter) etc., package unit is extremely complicated.The utility model equipment therefor only comprises a water-gas mixer, a water temperature control device, two gas meters, a welding bottle, a carrier gas bottle and a reference dissolved oxygen sensor, dissolved oxygen sensor to be calibrated, a stirrer, use easy device to achieve the functions such as water temperature maintenance, Dissolved Oxygen in Water concentration gradient structure, the acquisition of Dissolved Oxygen in Water standard value, significantly improve the work efficiency that dissolved oxygen sensor is demarcated.
With application number for compared with dissolved oxygen sensor scaling method described in the Chinese patent of CN201310637434 and device (hereinafter referred to as existing dissolved oxygen sensor scaling method), the utility model is mainly optimized in the following aspects, thus improves optical dissolved oxygen sensor calibration result accuracy and the scope of application:
Calibration point is arranged: existing dissolved oxygen sensor scaling method uses 6 groups of nitrogen preparing in advance and oxygen mixed gas to carry out transducer calibration, calibration point is limited to 6, and due to mixed gas need accurate formulation in advance, calibration point change cannot be carried out in calibration process.The utility model adopts a welding bottle and a carrier gas bottle, blending ratio is controlled by gas meter, only need two gas cylinders can build the water body environment of any saturation dissolved oxygen, therefore in the quantity and concentration selection of calibration point, all there is significant advantage.
Temperature applicable range: existing dissolved oxygen sensor scaling method only uses a temperature spot to carry out transducer calibration, and the mensuration of optical dissolved oxygen sensor and temperature have extremely close relation, the utility model adopts five temperature spots to carry out transducer calibration, and temperature spot change can be carried out according to sensor environment for use temperature, significantly can improve the applicability of calibration result when reality uses.
Standard value accuracy: sensor is placed in composition gas (N by existing dissolved oxygen sensor scaling method
2and O
2mixed gas) in demarcate, the solubleness of composition gas in a certain temperature water body according to specific oxygen content calculates Dissolved Oxygen in Water concentration.The solubleness audient multifactor impact of gas in water, although the impact that the process employs that temperature compensation reduces temperature as far as possible, calculated value and measured value still have certain difference.In addition, in the measurement result of sensor in gas and water body, there is some difference, even if still can there is certain error through the sensor of Accurate Calibration when actual water body environment uses in gas.The utility model adopts iodimetric titration measured value as demarcation standard value, has higher accuracy, directly can be traceable to national standard.
In sum, the utility model is all superior than existing method in device simplification, calibration point quantity, temperature applicable range, standard value accuracy, has good application value.
Claims (2)
1., for the device of optical dissolved oxygen sensor high-precision calibrating, comprise dissolved oxygen sensor to be calibrated; It is characterized in that, this device also comprises: the water-bath of welding bottle, carrier gas bottle, water-gas mixer, band water temperature control device, water-gas mixer, two gas meters, reference dissolved oxygen sensor and stirrers; Water-gas mixer is airtight container shape, and stirrer and air-blowing sandspit are established in its inside, and water-gas mixer entirety is placed in water-bath; Filled with water in water-gas mixer, reference dissolved oxygen sensor and dissolved oxygen sensor to be calibrated immerse in water from its top drilling; Water-gas mixer is provided with gas access and gas vent, and gas access is simultaneously as iodimetric titration sample tap; Welding bottle and carrier gas bottle are connected to air-blowing sandspit through reduction valve, gas meter, gas access successively respectively by pipeline.
2. device according to claim 1, is characterized in that, the cylindrical staving of described water-gas mixer.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104515761A (en) * | 2014-12-20 | 2015-04-15 | 国家***第二海洋研究所 | High-precision optical dissolved oxygen sensor calibration method and device |
| CN107515208A (en) * | 2017-09-14 | 2017-12-26 | 浙江省城乡规划设计研究院 | Dissolved oxygen detection method and its special calibrating device and measure device inside a kind of aerobic biologic membrane based on fluorescent quenching |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104515761A (en) * | 2014-12-20 | 2015-04-15 | 国家***第二海洋研究所 | High-precision optical dissolved oxygen sensor calibration method and device |
| CN104515761B (en) * | 2014-12-20 | 2017-05-17 | 国家***第二海洋研究所 | High-precision optical dissolved oxygen sensor calibration method and device |
| CN107515208A (en) * | 2017-09-14 | 2017-12-26 | 浙江省城乡规划设计研究院 | Dissolved oxygen detection method and its special calibrating device and measure device inside a kind of aerobic biologic membrane based on fluorescent quenching |
| CN107515208B (en) * | 2017-09-14 | 2023-08-04 | 浙江省城乡规划设计研究院 | Method for detecting dissolved oxygen in aerobic biomembrane based on fluorescence quenching, and special calibration device and measuring device |
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Granted publication date: 20150506 Termination date: 20201220 |