CN113702149A - Infrared thermal imaging acid-removing constant volume method - Google Patents
Infrared thermal imaging acid-removing constant volume method Download PDFInfo
- Publication number
- CN113702149A CN113702149A CN202111015012.8A CN202111015012A CN113702149A CN 113702149 A CN113702149 A CN 113702149A CN 202111015012 A CN202111015012 A CN 202111015012A CN 113702149 A CN113702149 A CN 113702149A
- Authority
- CN
- China
- Prior art keywords
- volume
- acid
- reaction tank
- thermal imaging
- infrared thermal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001931 thermography Methods 0.000 title claims abstract description 69
- 238000000034 method Methods 0.000 title claims abstract description 61
- 239000007788 liquid Substances 0.000 claims abstract description 100
- 238000006243 chemical reaction Methods 0.000 claims abstract description 96
- 230000029087 digestion Effects 0.000 claims abstract description 84
- 239000002253 acid Substances 0.000 claims abstract description 47
- 238000004364 calculation method Methods 0.000 claims abstract description 15
- 238000010438 heat treatment Methods 0.000 claims description 91
- 239000000523 sample Substances 0.000 claims description 17
- 238000010926 purge Methods 0.000 claims description 10
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 7
- 229910052753 mercury Inorganic materials 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 5
- 229910052785 arsenic Inorganic materials 0.000 claims description 3
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 3
- 238000002474 experimental method Methods 0.000 claims description 3
- 238000000338 in vitro Methods 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000012360 testing method Methods 0.000 claims description 3
- 230000001788 irregular Effects 0.000 claims 1
- 238000001704 evaporation Methods 0.000 abstract description 7
- 230000008020 evaporation Effects 0.000 abstract description 7
- 238000010521 absorption reaction Methods 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 5
- 239000008267 milk Substances 0.000 description 4
- 210000004080 milk Anatomy 0.000 description 4
- 235000013336 milk Nutrition 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000003384 imaging method Methods 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000010408 sweeping Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000009616 inductively coupled plasma Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000120 microwave digestion Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
Abstract
According to the infrared image of the interior of the reaction tank shot by the infrared thermal imaging sensor and the liquid evaporation heat absorption principle, when liquid is heated and evaporated, the surface temperature of the liquid is lower than the ambient temperature, and the condition of the residual surface area of the digestion liquid in the reaction tank can be clearly known. Then, the residual volume of the digestion solution can be calculated according to the bottom shape of the specific reaction tank, so that the real-time constant volume of the acid removing process is realized. The infrared thermal imaging sensor is matched with the blower, so that the problems of strong acid and overhigh ambient temperature which are possibly encountered in the process of removing acid and fixing volume are solved, and the environmental adaptability of the sensor is greatly improved. The invention combines the specially designed bottom shape in the reaction tank, and can meet various constant volume precision calculation requirements through a simple algorithm.
Description
Technical Field
The invention belongs to the technical field of analytical chemistry, and particularly relates to an infrared thermal imaging acid-expelling constant volume method.
Background
In the microwave chemical sample pretreatment process, samples such as soil, food, medicines or cosmetics are completely digested. Reagents such as nitric acid, hydrofluoric acid, hydrochloric acid or hydrogen peroxide and the like in different proportions are usually added according to the national standard method. And adding the sample and the reagent into a reaction tank for closed microwave heating reaction to finally obtain a digestion solution which is completely digested.
Because the existing analytical instruments such as ICP-MARS (inductively coupled plasma mass spectrometry), ICP-OES (inductively coupled plasma emission spectrometer) or AAS (atomic absorption spectroscopy) have limited tolerance to acid, the detection result is easily influenced by high-concentration acid. Therefore, after a general sample is digested, an acid removing process is needed to be carried out, and acid in the digestion solution is heated and evaporated. Generally, the volume of digestion liquid is 5-8ml immediately after digestion, and the digestion liquid needs to be heated to drive acid to about 0.5 ml. And finally diluting the digestion liquid after acid dispelling to 25ml or 50ml, and detecting by using an analytical instrument.
People who have done sample pretreatment know that the volume of dispelling acid of sample is very troublesome thing because digestion liquid is heated the back, and the inside acid of liquid can constantly evaporate into sour gas, and a large amount of sour gas overflows from the retort, corrodes the not corrosion-resistant object around easily. And in order to judge whether the volume of the digestion solution is concentrated to about 0.5ml or not in the acid dispelling process, an operator needs to frequently take up to observe and manually fix the volume. Even if an operator wears gloves, goggles and experimental clothes, a large amount of acid gas around the operator can threaten the human body, and safety accidents are easy to happen if the operator cares little.
In order to solve the problems of evaporation and condensation of acid gas, improve the environment and accelerate the acid-removing speed, a plurality of manufacturers have provided various acid-removing constant volume methods:
vacuum negative pressure acid removing method: the acid removing method is only to add a sealing cover connected to a negative pressure collecting device on the reaction tank to collect acid gas, and simultaneously, the negative pressure can reduce the boiling point of liquid to play a role in accelerating the evaporation of digestion liquid. The volume fixing of the acid removing process still needs to be observed by manually opening the sealing cover from time to time, or the acid removing time is determined according to an empirical value. The acid-removing method has high operation strength, high process danger and high requirement on experience of operators, otherwise, the acid-removing method is easy to remove excessively, and the digestion solution is evaporated, so that the loss of volatile samples is caused.
An ultrasonic automatic constant volume acid removing method comprises the following steps: the ultrasonic automatic constant volume acid removing method generally comprises the steps of removing acid at normal pressure, arranging a mechanical arm on the top of a heating plate, additionally arranging an ultrasonic distance sensor on the mechanical arm, and finally additionally arranging an exhaust hood outside an instrument to extract evaporated acid gas. Although this kind of catch up with sour method can play automatic constant volume effect, the constant volume precision is not high, because ultrasonic sensor installs at the retort top, has about 150mm apart from the inside tank bottoms distance of retort, and this distance ultrasonic sensor measured surface probably needs about 20mm of diameter and requires the surfacing just can guarantee its distance measurement's accuracy. After the digestion solution is used for dispelling acid to less than 1ml, due to the molecular acting force and the bottom of the tank is generally in a circular arc shape or a conical shape, the shape of the digestion solution at the bottom of the reaction tank begins to gradually transit to a liquid drop shape, the surface of the liquid drop is reduced and uneven, and the specific numerical value cannot be measured by ultrasonic waves at the moment. Therefore, the ultrasonic automatic constant volume acid-removing method is generally only suitable for preliminary constant volume in the early stage or occasions with low requirement on constant volume precision.
Visual constant volume acid-removing method: the vision constant volume acid-removing method is to take a picture of a measured object by adopting a vision sensor and then calculate the area or volume of the picture according to the pixel ratio occupied by the measured object in the taken picture. Because the visual imaging principle is adopted, the requirement on background light is high on one hand, and the measured object and the surrounding background need to have obvious color difference on the other hand, otherwise, a picture with clear boundary is difficult to obtain. Because the requirements on background and light are high, and the digestion solution is almost colorless and transparent in many times, a picture with clear boundary is difficult to take, and the size of the liquid drop cannot be accurately calculated, so that no acid-dispelling volume-fixing product using the technology is found in the market.
Disclosure of Invention
In order to solve the problems, the invention provides an infrared thermal imaging acid-expelling constant volume method: according to the infrared image inside the reaction tank shot by the infrared thermal imaging sensor and the liquid evaporation heat absorption principle, when liquid is heated and evaporated, the surface temperature of the liquid is lower than the ambient temperature, and the condition of the residual surface area of the digestion liquid inside the reaction tank can be clearly known. Then, the residual volume of the digestion solution can be calculated according to the bottom shape of the specific reaction tank, so that the real-time constant volume of the acid removing process is realized. The infrared thermal imaging sensor has an imaging principle similar to that of a common camera, except that the camera uses visible light for imaging, the infrared thermal imaging sensor receives infrared rays radiated by an object, the infrared wavelengths and energies radiated by the object at different temperatures are different, the sensor receives different energy radiations radiated by various positions in a shooting range, and the different energy radiations are displayed on a display screen by using different color marks according to calculation and finally restored into an infrared image with certain resolution, which is also called a heat image. Each pixel point in the infrared image corresponds to a temperature value, the temperature distribution condition of a shot object can be visually seen from the infrared image, and the independent temperature value of each point can be known.
The technical scheme of the invention is as follows:
an infrared thermal imaging acid-expelling constant volume method comprises the following steps:
(1) placing a reaction tank filled with digestion solution in the infrared thermal imaging acid-removing and volume-fixing device into a heating body, and heating by the heating body; in the heating process, the infrared thermal imaging sensor is fixed right above the reaction tank or fixed on a peripheral mechanical arm, so that an infrared image detected by the infrared thermal imaging sensor can completely cover the liquid surface area of the digestion solution to be measured;
(2) collecting an infrared image detected by an infrared thermal imaging sensor when the acid is removed and the volume is fixed, wherein the temperature of a heating body area of the infrared image is T, and the temperature of a liquid level area is T2; defining the height of a digestion liquid level as h, the diameter D of the digestion liquid level, the radius of the circular arc at the bottom of the reaction tank as R, and the diameter of the reaction tank as D, wherein D is 2R;
when the liquid level height h of the reaction tank is less than R, the digestion solution is in a spherical segment shape, and the system calculates the liquid level diameter d at the moment according to pixel points or pixel proportions which are occupied by the liquid level area in the infrared image and correspond to the temperature T2;
knowing the liquid surface diameter d, the radius R of the sphere where the segment is located, according to the formula:
calculating the height h of the liquid level at the moment; then according to the formula:
calculating the volume V of the segment, namely the residual volume of the digestion solution; when the system judges that V is more than 0.5ml, the heating body keeps heating at the temperature T;
when the volume of the residual digestion solution is smaller and smaller, the shape of the liquid drop formed by the ellipse rotating around the minor axis in the in-vitro digestion solution is as follows:
the system calculates the liquid level diameter d according to the number of pixel points or the pixel proportion of the liquid level area in the infrared image, which correspond to the temperature T2; but the height h of the liquid drop can not be directly calculated, the height h of the liquid drop formed by 0.5ml of digestion solution at the bottom of the test tube with the radius R can be measured through an actual experiment, the proportion coefficient y between the height h and the liquid level diameter d is obtained through actual calculation, and the actual value of the y is 0.6-0.8;
suppose that
Then h is y d, and the final drop volume formula is:
after the system determines that the volume of the liquid drop meets the requirement that V is 0.5ml +/-0.2 ml, the heating is stopped, the reaction tank is taken out, or an external mechanical arm is utilized, the reaction tank is removed from a heating body, and the whole process of removing acid and fixing the volume is completed.
According to the infrared thermal imaging acid-expelling constant volume method, furthermore, when the actual constant volume requirement precision is not high, and the constant volume is calculated, the digestion liquid drop is regarded as a sphere for calculation, and the calculation formula can be simplified as follows:
after the system determines that the volume of the liquid drop meets the requirement that V is 0.5ml +/-0.2 ml, the heating is stopped, the reaction tank is taken out, or an external mechanical arm is utilized, the reaction tank is removed from a heating body, and the whole process of removing acid and fixing the volume is completed.
Further, when the infrared thermal imaging acid-removing constant volume method is used for measuring mercury and arsenic, the temperature of a heating body is set to be 130-140 ℃; when the element which is difficult to volatilize is measured, it can be set to 140 to 180 ℃.
According to the infrared thermal imaging acid-removing constant volume method, further, infrared images detected by an infrared thermal imaging sensor are collected by a system and can be divided into a heating body area, a tank body area and a liquid level area, the temperatures of the three areas are T, T1 and T2 respectively, and T > T1 > T2.
According to the infrared thermal imaging acid-removing constant volume method, when acid-removing is started, the liquid level height is not lower than the arc-shaped area at the bottom inside the reaction tank due to the large volume of the digestion solution, namely h is not less than R, and the liquid level diameter D is equal to the diameter D inside the reaction tank; at the moment, the volume of the digestion solution is far larger than 0.5ml required by constant volume, the system does not need to calculate the volume of the digestion solution, the constant volume process is judged to belong to the initial constant volume stage directly according to the value of the liquid surface diameter d, and the heating body is kept to be heated continuously.
The invention also provides an infrared thermal imaging acid-removing constant volume device applied to the infrared thermal imaging acid-removing constant volume method, which comprises a heating body 4, wherein the heating body 4 is provided with a heating hole for placing the reaction tank 3, the infrared thermal imaging sensor 1 is arranged above the reaction tank 3, the blow-down device 2 is arranged below the probe lens of the infrared thermal imaging sensor 1, and the air inlet of the blow-down device is connected with the air outlet of the electromagnetic valve for communicating clean compressed air or nitrogen.
Further, the infrared thermal imaging sensor 1 is fixed right above the reaction tank in a mechanical fixing mode, or is fixed on a peripheral mechanical arm, and is moved right above the reaction tank by the mechanical arm when in use.
Further, the reaction tank 3 is of a cup-shaped structure, and the bottom in the tank can be in an arc shape or a regular shape such as a conical bottom.
Detailed description of the invention:
the infrared thermal imaging acid-expelling constant volume method mainly structurally comprises the following parts (shown in detail in figure 1): an infrared thermal imaging sensor 1, a blower 2, a reaction tank 3, a heating body 4 and a digestion liquid 5
Infrared thermal imaging sensor 1: an infrared thermal imaging sensor with a spectral range of 8-14 microns is selected, infrared with a wavelength of 8-14 microns has extremely strong penetrability on atmospheric substances such as water vapor, smoke cloud, carbon dioxide and the like, and the infrared thermal imaging sensor is called as an atmospheric window of thermal infrared. The invention is exemplified by the German optris model PI640, the parameters of which are shown in Table 1 and FIG. 2. The resolution of the sensor is 640 х 480, that is, within the field of view, the detected surface will be divided into 640 х 480 pixel points, which are then marked with different colors and displayed on the display screen, and finally restored to a 640 х 480 resolution infrared image. Assuming that the size of the measured surface is 64mmx48mm, the size of the pixel point is only 0.1mmx0.1 mm. After the system receives the infrared image output by the infrared thermal imaging sensor, the system can know the temperature of each pixel point on the detected surface. The thermal imaging sensor can measure the extremely fine temperature deviation, and provides good data support for the subsequent calculation of the liquid volume of the system.
| Model number | Temperature range | Optical resolution | Angle of view |
| PI640 | 0-250℃ | 640х480 | 15°х11° |
TABLE 1
Purge 2 (fig. 3): the purging device is a conventional purging device in the market, the conventional purging device is an air curtain generating device sleeved below the probe lens, an air inlet of the purging device is connected with an air outlet of an electromagnetic valve communicated with clean compressed air or nitrogen through a pipeline, the electromagnetic valve is controlled by a system, and the system controls the working state of the purging device by controlling the opening and closing of the electromagnetic valve. The special air channel is arranged in the blower, air flow is uniformly blown out from the outlet of the air channel after passing through the air channel, an air curtain is formed, the air curtain is blown out from the blower, acid gas can be prevented from entering the interior of the blower, and therefore the probe lens arranged in the blower is effectively prevented from being corroded by the acid gas. Meanwhile, due to the sweeping function of the sweeping device, the temperature of blown gas is low, the infrared thermal imaging sensor 1 can be swept and cooled, and the using environment temperature of the infrared thermal imaging sensor is greatly improved. In the whole acid-removing constant-volume working process, the purging device is always in a working state, and the lens of the infrared thermal imaging sensor is protected from time to time.
Reaction tank 3 (see fig. 4): the material of the reaction tank is PFA or PTFE and the like, so long as the corrosion resistance, the temperature resistance, the strength and the microwave penetrability meet the use requirements. The retort is cup-shaped structure generally, and inside is used for holding digestion liquid 5, and the bottom can be for regular shape such as arc or awl end in the jar, and the digestion liquid gathers together in the process of being convenient for catch up with sour, makes things convenient for the volume to calculate. This patent is introduced as an example with the retort at the bottom of the arc, and retort inner wall comprises top column surface and bottom arc surface, can form the intersection line between two surfaces, defines this intersection line as the boundary line (the combination of column surface and arc surface can form an intersection line naturally, and this intersection line is exactly the boundary line). When acid is removed, the reaction tank is placed in a heating hole of the heating body 4, and the heating body can heat the reaction tank.
Heating body 4 (fig. 5): the heating body is a conventional graphite or aluminum alloy electric heating body, and only needs to have a heating function and realize the heating control of temperature under the control of a control system. The heating body is provided with a heating hole, and the reaction tank 3 is arranged in the heating hole. In the process of acid expelling and volume fixing, the heating body is controlled by the system, the temperature of the heating body is adjusted in real time, and temperature guarantee is provided for continuous evaporation of digestion liquid in the reaction tank.
The working principle and the method of the invention (as shown in figure 6, figure 7, figure 8 and figure 9):
the reaction tank 3 with the digestion solution 5 inside is put into the heating hole of the heating body 4. The system controls the heating body to heat, the heating temperature is T, and the heating temperature value is set by a user according to specific components of the digestion liquid, generally, the digestion liquid does not boil, so that element loss caused by boiling is avoided. If the mercury and arsenic elements are to be measured, the temperature of the heater is generally set at 130 to 140, and for the determination of the elements which are less volatile, it may be set at 140 to 180. In the heating process, the infrared thermal imaging sensor 1 can be fixed right above the reaction tank by using a common mechanical fixing mode, and also can be fixed on a peripheral mechanical arm, and is moved right above the reaction tank by the mechanical arm when in use. The fixed height is only required to be that the infrared image detected by the infrared thermal imaging sensor can completely cover the detected liquid surface area. (see fig. 7)
When the acid is driven to a constant volume, the system collects an infrared image detected by an infrared thermal imaging sensor, the infrared image can be divided into a heating body area, a tank area and a liquid level area, and the temperatures of the three areas are T, T1 and T2 respectively. Since the heating body is a heating part, the reaction tank is a heat-conducting part, and the digestion solution is evaporated and radiated, the temperature relationship among the heating body and the digestion solution is that the temperature of the heating body area is higher than that of the tank area, and the temperature of the tank area is higher than that of the liquid level area, namely T is more than T1 and more than T2. Defining the height of a liquid level as h, the diameter of the liquid level as D, the radius of the circular arc at the bottom of the reaction tank as R, and the diameter of the reaction tank as D, wherein D is 2R.
At the beginning of acid removal, because the volume of the digestion solution is large, the liquid level height is not lower than the arc-shaped area of the bottom in the reaction tank, i.e. h ≧ R (FIG. 6a), and the liquid level diameter D is the same as the diameter D in the reaction tank. At the moment, the volume of the digestion solution is far larger than 0.5ml required by constant volume, so the system can directly judge that the constant volume process belongs to the initial constant volume stage according to the value of the liquid surface diameter d without calculating the volume, and the heating body is kept to be heated continuously.
As the acid removal continues, the digestion solution is continuously evaporated, the digestion solution level slowly drops, and when the liquid level is lower than the boundary, the liquid level h is less than R, and the digestion solution takes the shape of a spherical segment (as shown in FIG. 6b and FIG. 8). The measured surface is known to have a size of 64mmx48mm and an infrared image resolution of 640 х 480. The size of one pixel point is only 0.1 mmx0.1mm. The system can calculate the liquid level diameter d at the moment according to the number of pixel points or the pixel proportion of the liquid level area in the infrared image, which correspond to the temperature T2.
Knowing the liquid surface diameter d, the radius R of the sphere where the segment is located, according to the formula:
the liquid level height h at this time was calculated. Then according to the formula:
the volume V of the spherical segment, that is, the residual volume of the digestion solution at that time, is calculated. When the system judges that V is more than 0.5ml, the heating body keeps heating at the temperature T continuously.
When the volume of the residual digestion solution is smaller and smaller, the final digestion solution in vitro does not take on the shape of a spherical segment, but rather resembles the shape of a droplet formed by one revolution of an ellipse around the minor axis (see fig. 6c and fig. 9), and the volume of the droplet is calculated according to the following formula:
at this time, the system can calculate the liquid level diameter d at this time according to the number of pixels or the pixel proportion of the liquid level region in the infrared image, which corresponds to the temperature T2. But the height h of the liquid drop can not be directly calculated, the height h of the liquid drop formed by 0.5ml of digestion solution at the bottom of the test tube with the radius R can be measured through an actual experiment, the proportion coefficient y between the height h and the liquid level diameter d is obtained through actual calculation, and the actual value of the y is about 0.6-0.8.
Suppose that
Then h is y d, and the final drop volume formula is:
when the volume is actually fixed, the use requirement is met when the common volume fixing precision requirement V is 0.5ml +/-0.2 ml:
assuming that the final diameter of the digestion droplet is 10mm, when y is 0.6, the volume is:
assuming that the droplet is regarded as a sphere, i.e. y is 1, the droplet volume is:
that is to say, if the precision required by the actual constant volume is not high, and the digestion liquid drop can be directly regarded as a sphere for calculation during constant volume calculation, the calculation formula can be simplified as follows:
after the system determines that the volume of the liquid drop meets the requirement that V is 0.5ml +/-0.2 ml, the heating can be stopped, an operator is informed to take out the reaction tank, or the reaction tank is removed from the heating body by utilizing an external mechanical arm, and the whole process of removing acid and fixing volume is completed.
The invention has the beneficial technical effects that:
1. according to the invention, an infrared thermal imaging sensor in a spectral range of 8-14 microns is selected, the thermal imaging technology is utilized to track the size of liquid drops in the acid dispelling process of the digestion solution, the penetrability of smog, acid gas and the like is strong, compared with a visual sensor, a backlight system does not need to be built, and the whole system is simple and strong in stability.
2. The infrared thermal imaging sensor is matched with the blower, so that the problems of strong acid and overhigh ambient temperature which are possibly encountered in the acid-removing and volume-fixing processes are solved, and the environmental adaptability of the sensor is greatly improved.
3. And the calculation requirements of various constant volume precision can be met by combining the specially designed bottom shape in the reaction tank through a simple algorithm.
4. According to the infrared image inside the reaction tank shot by the infrared thermal imaging sensor and the liquid evaporation heat absorption principle, when liquid is heated and evaporated, the surface temperature of the liquid is lower than the ambient temperature, the condition of the residual surface area of the digestion liquid inside the reaction tank can be clearly known, and the acid removing and volume fixing are safer and more accurate.
Description of the drawings:
FIG. 1 is a diagram of an infrared thermal imaging acid-removing volume-setting device.
Fig. 2 is a schematic diagram of an infrared thermal imaging sensor.
FIG. 3 is a schematic diagram of a purge unit.
FIG. 4 is a structural diagram of different types of reaction tanks, wherein the bottom of d is arc-shaped, and the bottom of e is conical.
Fig. 5 is a structural view of the heating body.
FIG. 6 is a schematic diagram of the liquid level of the digestion solution, wherein a, the liquid level is not lower than the arc-shaped area at the bottom in the reaction tank, i.e. h is not less than R; b, the height h of the liquid level is less than R, and the digestion solution is in a spherical segment shape; c the digestion solution takes the shape of a droplet.
FIG. 7 is a schematic view of infrared image partitions detected by an infrared thermal imaging sensor.
FIG. 8 shows a schematic view of the digestion solution in the form of spherical segment.
Fig. 9 shows a schematic view of the shape of a droplet of the digestion solution.
Wherein: 1-sensor, 2-purger, 3-reaction tank, 4-heating body, 5-digestion liquid, 6-view field, 7-pixel point, 8-measured surface, 9-air inlet, 10-air curtain, 11-boundary line, 12-arc bottom, 13-cone bottom, 14-heating hole, 15-heating body area, 16-tank body area and 17-liquid area.
The specific implementation mode is as follows:
various exemplary embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise.
Example 1: non-automated system embodiment:
this example requires the determination of lead content in milk powder.
And starting the system equipment, wherein after the equipment is started, the system control electromagnetic valve is connected with the gas circuit, the purger keeps a working state, and the equipment initialization is completed. The reaction pot with the constant volume digestion solution required to remove acid is put into a heating body, the digestion solution is obtained by adding 0.5g of milk powder and 7ml of nitric acid into the milk powder and performing microwave digestion, and about 6.5ml of digestion solution is obtained. The heating temperature was set to 160 ℃ and the volumetric volume was set to 0.5 ml.
And (3) starting clicking, controlling the heating body to heat to 160 ℃ by the system, keeping the temperature, analyzing the infrared image acquired by the infrared thermal imaging sensor in real time by the system in the whole heating process, analyzing and calculating the volume V of the residual digestion solution according to the infrared image, and judging that V is larger than 0.5 or V is smaller than or equal to 0.5. And when the V is more than 0.5, the heating system control body continues to heat, and the infrared thermal imaging sensor continues to collect infrared images, analyze and calculate the volume V and compare the volume V with 0.5. When the V calculated by the system is less than or equal to 0.5, the volume of the digestion solution is close to or less than 0.5ml, the heating body is controlled by the system to stop heating at the moment, and meanwhile, an interface gives a completion prompt to prompt an operator to complete volume fixing.
And taking out the reaction tank which finishes acid-expelling and volume-fixing, wherein the volume of the residual digestion solution in the reaction tank is 0.5ml required, adding pure water directly to supplement the volume to 50ml, and then directly sampling to analyze the lead content in the reaction tank.
Example 2: an automated system embodiment:
taking the measurement of lead and mercury content in milk powder as an example.
The system is provided with an automatic mechanical arm, an infrared thermal imaging sensor is arranged on the mechanical arm, the mechanical arm is provided with a gripper capable of clamping reaction tanks, and the system is provided with a sample rack capable of placing a plurality of reaction tanks and 2 or more heating bodies.
After a user starts the system equipment, the system controls the electromagnetic valve to be connected with the gas circuit, the blower keeps a working state, the system controls the mechanical arm to complete the original point reset work, and the equipment initialization is completed.
And placing a plurality of reaction tanks in which the acid-removing constant-volume digestion solution needs to be removed into a sample rack, and then placing the sample rack at a sample rack fixed position appointed by the system. The heating temperature and the constant volume of each reaction tank are set according to the position on the sample rack. The No. 1 reaction tank is used for measuring lead element, lead is not easy to volatilize, the heating temperature is 160 ℃, and the constant volume is set to be 0.5 ml. The No. 2 reaction tank is used for measuring mercury elements, the mercury is easy to volatilize, the heating temperature is 120 ℃, and the constant volume is set to be 0.5 ml.
And (3) starting clicking, clamping the reaction tank No. 1 by the system control mechanical arm, putting the reaction tank No. 1 into the heating body No. 1, and simultaneously controlling the heating temperature of No. 1 to be increased to 160 ℃ and preserving the heat. The system control mechanical arm clamps the reaction tank No. 2 and puts the heating body No. 2 in, and simultaneously controls the heating body No. 2 to heat up to 120 ℃ and preserve heat. After the reaction tank clamping is completed, the system can control the mechanical arm to move, and the infrared thermal imaging sensor arranged on the mechanical arm moves back and forth to the position above the reaction tank in 5 seconds and collects infrared external images in turn repeatedly. As the whole acid-removing volume-fixing process needs 1-2 hours to remove 5ml of acid to 0.5ml, the acid-removing rate is slow even if the acid-removing process only needs about 0.05ml in the next minute, the mode that the mechanical arm repeatedly collects the infrared images of each reaction tank one by one in 5 seconds does not affect the precision of the acid-removing volume-fixing.
The system analyzes and calculates the volume V of the residual digestion solution according to the infrared image of each reaction tank, and judges that V is more than 0.5 or V is less than or equal to 0.5. And when the V is more than 0.5, the heating system control body continues to heat, and the infrared thermal imaging sensor continues to collect infrared images, analyze and calculate the volume V and compare the volume V with 0.5. When the V calculated by the system is less than or equal to 0.5, the volume of the current digestion solution is close to or less than 0.5ml, and at the moment, the system controls the mechanical arm to take out the reaction tank from the heating body and return the reaction tank to the sample rack. And after the reaction tank finishes the constant volume and is placed back to the sample rack, the digestion solution in the reaction tank is used for dispelling acid and finishing the constant volume.
After the retort on the heating body is taken away, the system can judge whether still have the retort to heat, if have then press the temperature that a retort set for and carry out the temperature adjustment heating, the arm can be got the retort clamp simultaneously and put into the heating body, continues adding the sour constant volume of catching up of a retort, if do not, then this passageway heating body stops to heat.
When the system judges that all the reaction tanks set by the user are acid-dispelling and volume-fixing completed, all the reaction tanks are taken out and put back to the sample rack, all the heating bodies are closed by the system, the mechanical arm is reset, the interface displays that the states of all the tanks are the completion states, and at the moment, the work of the whole system is finished.
After the system works, the reaction tank which finishes acid-removing and volume-fixing is taken out, the volume of the remaining digestion solution in the reaction tank is 0.5ml required, the volume is supplemented to 50ml, and then the solution is directly loaded to a back-end analysis social security, so that the lead content in the reaction tank No. 1 and the mercury content in the reaction tank No. 2 can be analyzed.
The working principle and the calculation method and the embodiment described above are only exemplified and calculated by taking the main process status related to the acid-expelling volumetric method. The invention mainly comprises the following steps: the method is a method which utilizes the thermal imaging function of a high-resolution infrared thermal imaging sensor on each pixel point, simultaneously utilizes the temperature difference phenomenon formed by the evaporation and heat absorption of digestion solution and a reaction tank, and the shape of the bottom in the reaction tank with unique design, accurately tracks and calculates the volume change of the digestion solution drop in the acid dispelling process, and finally fixes the volume of the digestion solution drop to a set volume. The actual volume-fixing calculation process and the size and shape of the reaction tank can be adjusted according to the actual volume-fixing requirement, as long as the method principle is the same as that of the method, and the characteristics of the method are not violated.
Claims (8)
1. An infrared thermal imaging acid-dispelling constant volume method is characterized by comprising the following steps:
(1) placing a reaction tank filled with digestion solution in the infrared thermal imaging acid-removing and volume-fixing device into a heating body, and heating by the heating body; in the heating process, the infrared thermal imaging sensor is fixed right above the reaction tank or fixed on a peripheral mechanical arm, so that an infrared image detected by the infrared thermal imaging sensor can completely cover the liquid surface area of the digestion solution to be measured;
(2) collecting an infrared image detected by an infrared thermal imaging sensor when the acid is removed and the volume is fixed, wherein the temperature of a heating body area of the infrared image is T, and the temperature of a liquid level area is T2; defining the height of a digestion liquid level as h, the diameter D of the digestion liquid level, the radius of the circular arc at the bottom of the reaction tank as R, and the diameter of the reaction tank as D, wherein D is 2R;
when the liquid level height h of the reaction tank is less than R, the digestion solution is in a spherical segment shape, and the system calculates the liquid level diameter d at the moment according to pixel points or pixel proportions which are occupied by the liquid level area in the infrared image and correspond to the temperature T2;
knowing the liquid surface diameter d, the radius R of the sphere where the segment is located, according to the formula:
calculating the height h of the liquid level at the moment; then according to the formula:
calculating the volume V of the segment, namely the residual volume of the digestion solution; when the system judges that V is more than 0.5ml, the heating body keeps heating at the temperature T;
when the volume of the residual digestion solution is smaller and smaller, the shape of the liquid drop formed by the ellipse rotating around the minor axis in the in-vitro digestion solution is as follows:
the system calculates the liquid level diameter d according to the number of pixel points or the pixel proportion of the liquid level area in the infrared image, which correspond to the temperature T2; but the height h of the liquid drop can not be directly calculated, the height h of the liquid drop formed by 0.5ml of digestion solution at the bottom of the test tube with the radius R can be measured through an actual experiment, the proportion coefficient y between the height h and the liquid level diameter d is obtained through actual calculation, and the actual value of the y is 0.6-0.8;
suppose that
Then h is y d, and the final drop volume formula is:
after the system determines that the volume of the liquid drop meets the requirement that V is 0.5ml +/-0.2 ml, the heating is stopped, the reaction tank is taken out, or an external mechanical arm is utilized, the reaction tank is removed from a heating body, and the whole process of removing acid and fixing the volume is completed.
2. The infrared thermal imaging acid-expelling volume-fixing method as claimed in claim 1,
when the precision required by actual constant volume is not high, and the constant volume is calculated, the digestion liquid drop is regarded as a sphere, and the calculation formula can be simplified as follows:
after the system determines that the volume of the liquid drop meets the requirement that V is 0.5ml +/-0.2 ml, the heating is stopped, the reaction tank is taken out, or an external mechanical arm is utilized, the reaction tank is removed from a heating body, and the whole process of removing acid and fixing the volume is completed.
3. The infrared thermal imaging acid-removing volume-fixing method as claimed in claim 1, wherein the temperature of the heating body is set to 130-140 ℃ when measuring the mercury and arsenic; when the element which is difficult to volatilize is measured, it can be set to 140 to 180 ℃.
4. The infrared thermal imaging acid-expelling volume-fixing method as claimed in claim 1,
the system collects infrared images detected by the infrared thermal imaging sensor, the infrared images can be divided into a heating body area, a tank body area and a liquid level area, the temperatures of the three areas are T, T1 and T2 respectively, and T > T1 > T2.
5. The infrared thermal imaging acid-removing volume-constant method as claimed in claim 1, wherein, at the beginning of acid-removing, the height of the liquid level is not lower than the arc-shaped area at the bottom of the reaction tank due to the large volume of the digestion solution, i.e. h ≧ R, and the diameter D of the liquid level is equal to the diameter D of the reaction tank; at the moment, the volume of the digestion solution is far larger than 0.5ml required by constant volume, the system does not need to calculate the volume of the digestion solution, the constant volume process is judged to belong to the initial constant volume stage directly according to the value of the liquid surface diameter d, and the heating body is kept to be heated continuously.
6. The infrared thermal imaging acid-dispelling constant volume device applied to the infrared thermal imaging acid-dispelling constant volume method comprises a heating body (4), wherein the heating body (4) is provided with a heating hole capable of placing a reaction tank (3), the infrared thermal imaging acid-dispelling constant volume device is characterized in that an infrared thermal imaging sensor (1) is arranged above the reaction tank (3), a purging device (2) is arranged below a probe lens of the infrared thermal imaging sensor (1), and an air inlet of the purging device is connected with an air outlet of an electromagnetic valve which is communicated with clean compressed air or nitrogen.
7. The infrared thermal imaging acid-dispelling and volume-fixing device as claimed in claim 6, wherein the infrared thermal imaging sensor (1) is fixed directly above the reaction tank by a mechanical fixing manner, or fixed on a peripheral mechanical arm, and is moved directly above the reaction tank by the mechanical arm when in use.
8. The infrared thermal imaging acid-driving volume-fixing device as claimed in claim 6, wherein the reaction tank (3) is a cup-shaped structure, and the bottom of the tank can be in an arc shape or an irregular shape such as a cone bottom.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111015012.8A CN113702149B (en) | 2021-08-31 | 2021-08-31 | Infrared thermal imaging acid-removing constant volume method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111015012.8A CN113702149B (en) | 2021-08-31 | 2021-08-31 | Infrared thermal imaging acid-removing constant volume method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113702149A true CN113702149A (en) | 2021-11-26 |
| CN113702149B CN113702149B (en) | 2024-02-02 |
Family
ID=78658226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111015012.8A Active CN113702149B (en) | 2021-08-31 | 2021-08-31 | Infrared thermal imaging acid-removing constant volume method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113702149B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114778265A (en) * | 2022-04-28 | 2022-07-22 | 中国第一重型机械股份公司 | Heating-free digestion method and device for chemical analysis sample |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204789083U (en) * | 2015-07-13 | 2015-11-18 | 广东出入境检验检疫局检验检疫技术中心 | Food heavy metal detects super microwave digestion solution and catches up with acid mist and direct constant volume device fast |
| CN106769389A (en) * | 2017-02-08 | 2017-05-31 | 朱山 | One kind quickly catches up with sour instrument |
| CN206656911U (en) * | 2017-04-28 | 2017-11-21 | 山东百纳瑞分析仪器科技有限公司 | Fully automatic high temperature high pressure constant volume clears up instrument |
| CN111781054A (en) * | 2020-06-19 | 2020-10-16 | 广西壮族自治区亚热带作物研究所（广西亚热带农产品加工研究所） | Acid removing device and acid removing system |
-
2021
- 2021-08-31 CN CN202111015012.8A patent/CN113702149B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204789083U (en) * | 2015-07-13 | 2015-11-18 | 广东出入境检验检疫局检验检疫技术中心 | Food heavy metal detects super microwave digestion solution and catches up with acid mist and direct constant volume device fast |
| CN106769389A (en) * | 2017-02-08 | 2017-05-31 | 朱山 | One kind quickly catches up with sour instrument |
| CN206656911U (en) * | 2017-04-28 | 2017-11-21 | 山东百纳瑞分析仪器科技有限公司 | Fully automatic high temperature high pressure constant volume clears up instrument |
| CN111781054A (en) * | 2020-06-19 | 2020-10-16 | 广西壮族自治区亚热带作物研究所（广西亚热带农产品加工研究所） | Acid removing device and acid removing system |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114778265A (en) * | 2022-04-28 | 2022-07-22 | 中国第一重型机械股份公司 | Heating-free digestion method and device for chemical analysis sample |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113702149B (en) | 2024-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20120002192A1 (en) | Automated Soil Measurement Device | |
| US20240027481A1 (en) | Automated specimen deposition systems and associated methods | |
| EP2799836B1 (en) | Mist-containing gas analysis device | |
| CN113702149A (en) | Infrared thermal imaging acid-removing constant volume method | |
| CN104215598B (en) | Spacecraft Material outgassing constituent online infrared absorption spectroscopy detecting system | |
| US6620620B1 (en) | Micro liquid evaporator | |
| CN112858106B (en) | System and method for measuring liquid drop contact angle | |
| CN108398428A (en) | The optical detecting method of residual liquid in a kind of Rotary Evaporators | |
| Unger et al. | Variable-temperature Fourier transform near-infrared (FT-NIR) imaging spectroscopy of the diffusion process of butanol (OD) into polyamide 11 | |
| CN113916865B (en) | Online Raman measurement method for air retention performance of hollow microspheres | |
| RU160148U1 (en) | IR-SPECTROMETRIC CELL FOR DETERMINING EASY VOLATILE ORGANIC LIQUIDS IN MIXTURES WITH WATER | |
| CN207894844U (en) | A kind of bearing device inside non-destructive testing imaging device | |
| CN114624150A (en) | Contact angle measuring method for micro and macro simultaneous measurement and mutual verification | |
| Imhof et al. | New developments in skin barrier measurements | |
| US7556716B2 (en) | Method for recording the boiling curve of liquids and device for carrying out the method | |
| CN101738410A (en) | Multi-unit inspection full-automatic solidification point analyser | |
| Braue et al. | Imprecision in Circle cell FT-IR analysis of aqueous solutions | |
| CN104965048A (en) | Liquid ammonia content rapid measurement method | |
| CN106524957A (en) | Method for measuring dimension of pearlite colony | |
| CN212008312U (en) | Gas-liquid heterogeneous reaction in-situ infrared spectrum testing system | |
| CN110763672A (en) | Method for measuring total sulfur in soil or water system sediment | |
| Flowers et al. | Infrared spectroscopic determination of oxide in molten chloroaluminates | |
| CN116858729B (en) | Portable miniature contact angle tester | |
| Kitagawa et al. | A quantitative detector-tube method for breath-alcohol estimation | |
| CN113588491B (en) | Dissolved gas liquid density measuring device and method based on image processing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |