CN203981303U - The superhigh precision digit thermometer that replaces accurate mercury thermometer - Google Patents
The superhigh precision digit thermometer that replaces accurate mercury thermometer Download PDFInfo
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- CN203981303U CN203981303U CN201420253240.8U CN201420253240U CN203981303U CN 203981303 U CN203981303 U CN 203981303U CN 201420253240 U CN201420253240 U CN 201420253240U CN 203981303 U CN203981303 U CN 203981303U
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Abstract
The utility model discloses a kind of superhigh precision digit thermometer that replaces accurate mercury thermometer, it has supporting body, printed circuit board (PCB), temperature detection device, display device, temperature detection device selects two pearl series compensation structures or two pearl is complementary and series compensation structure, two pearl series compensation structures: with the second thermistor series connection the 3rd thermistor, form complementary type temperature detection device; The complementary also series compensation structure of two pearls: form the first series compensation structure with the 4th thermistor series connection the 5th thermistor, then this first series compensation structure the 3rd compensating resistance in parallel and form the second parallel-connection structure again, then connects the 4th compensating resistance again and forms temperature detection device at the second parallel-connection structure.It is high that this temperature measurer has precision, the advantage that stability is strong.
Description
Technical field
The utility model relates to temperature measuring tool, especially relates to a kind of superhigh precision digit thermometer that replaces accurate mercury thermometer.
Background technology
In temperature survey field, can make the instrument of high-precision temperature measurement nothing more than electronic instrument and the large class of mercury thermometer two.At present, the electronic instrument that can be used for doing high-acruracy survey is also confined to take the instrument that platinum resistance is made as temperature-sensing element, but due to platinum resistance, to vary with temperature the resistance variation changing very little, forms circuitry comparatively complicated, to such an extent as to machine volume is large, cost is high, and be difficult to penetration and promotion.
At present everyly need to carry out high-precision temperature survey, as departments such as meteorology, oil, temperature standard and scientific researches, be nearly all to select mercury thermometer as unique survey instrument, although mercury thermometer all can cause in production and use procedure, environment for human survival brought to trouble evil difficult to the appraisal.But can replace so that allow this phenomenon continue into the present and have upper one-hundred-year history without desirable product.
Mercury is commonly called as mercury, under normal temperature condition, can be evaporated to mercury vapour, very easily makes air, water quality and soil be polluted.1 milligram of mercury can pollute 360 tons of water, and 20 grams of mercury can make Huangpu River 100 years without fishes and shrimps.As far back as between nineteen fifty-three to 1973 year two decades, " minamata disease " of Japan is once because dead 86 people of mercury poisoning and people up to ten thousand obtain disease, as can be seen here, how serious the threat that mercury brings for environment for human survival has, rise last century, and just take the lead in expressly the forbidding use of all mercury thermometers of Switzerland, Sweden, Denmark, Norway four countries, in the beginning of this century, France also completely forbids use mercury thermometer, and carries out centralized recovery processing.Within 2012, EU countries also completely forbids, and the U.S. rose in 2013 also and completely forbids.
Sweden also expressly provides while even burning corpse and must pull up artificial tooth to prevent mercury diffusion, and compare China, not only generally use various mercury thermometers, not only do not forbidden, and become all kinds of mercury thermometer of unique production big country in the world, at present, except producing per year 200,000,000 branched mercury clinical thermometers, also produce all kinds of mercury thermometers as meteorology, oil, 13 large classes such as standard temperature, 853 kinds of temperature specification, year is consumed 300 tons of mercury, situation in the face of this sternness, the high accuracy number temperature measurer that application the utility model is made, not only can in measuring accuracy and function, surmount to some extent, and accomplishing also will be lower than accurate mercury thermometer in price.Because only in this way just can force mercury thermometer to step down from the stage of history.From source, stop the trouble evil that Mercury In Environment pollutes in temperature field, strive fulfiling ahead of schedule limit mercury index within the international Minamata pact prescribed timelimit.
Utility model content
The purpose of this utility model is exactly in order to address the above problem, and the superhigh precision digit thermometer of the accurate mercury thermometer of replacement that a kind of stability is high, discreteness is little is provided.
To achieve these goals, the utility model adopts following technical scheme:
The superhigh precision digit thermometer that replaces accurate mercury thermometer, it has:
Supporting body;
Be installed on the printed circuit board (PCB) of supporting body;
Be installed on the temperature detection device of supporting body, itself and printed circuit board (PCB) are electrically connected;
Be connected to the display device of printed circuit board (PCB);
Described temperature detection device selects two pearl series compensation structures or two pearl is complementary and series compensation structure, wherein,
Described pair of pearl series compensation structure: form complementary type temperature detection device with the second thermistor series connection the 3rd thermistor;
The described pair of complementary also series compensation structure of pearl: form the first series compensation structure with the 4th thermistor series connection the 5th thermistor, then this first series compensation structure the 3rd compensating resistance in parallel and form the second parallel-connection structure again, then connects the 4th compensating resistance again and forms temperature detection device at the second parallel-connection structure.
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, in the low-temperature range of-60-+60 ℃, the second~five thermistor can be selected the thermistor of corresponding temperature range, such as the 103AP-2 thermistor of Japanese stoneman company;
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, in between the middle warm area of-40-+100 ℃, the second~five thermistor can be selected the thermistor of corresponding temperature range, such as the 503ET thermistor of Japanese stoneman company;
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, in between the high-temperature region of 0-300 ℃, the second~five thermistor can be selected the thermistor of corresponding temperature range, such as the 504GT thermistor of Japanese stoneman company;
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, in the superhigh temperature interval of 0-400 ℃, the second~five thermistor can be selected the thermistor of corresponding temperature range, such as the F1-R thermistor of Japanese stoneman company.
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, described supporting body is shell structure.
Wherein, the pass between the second thermistor and the 3rd thermistor, the 4th thermistor and the 5th thermistor is:
The central value R of the second thermistor and the 3rd thermistor is multiplied by 2 for standardizing standard value, as get temperature while being T degree Celsius, central value R*2 is standardizing standard value 2R, the second thermistor is the thermistor of discreteness in-3% scope, the 3rd thermistor is the thermistor of discreteness in+3% scope, and resistance like this second thermistor and the 3rd thermistor is added and equals 2R;
The central value R of the 4th thermistor and the 5th thermistor is multiplied by 2 for standardizing standard value, as get temperature while being T degree Celsius, central value R*2 is standardizing standard value 2R, the 4th thermistor is the thermistor of discreteness in-3% scope, the 5th thermistor is the thermistor of discreteness in+3% scope, and resistance like this 4th thermistor and the 5th thermistor is added and equals 2R;
As replacing in the superhigh precision digit thermometer of accurate mercury thermometer, comparatively it is desirable to, the resistance of the 3rd compensating resistance is M Ω level;
The 4th compensating resistance is that 1000 Ω are with interior resistance.
The utlity model has following beneficial effect:
Its with easy and resistance in series and with the thermistor of same model through batch thermometric necessarily after resistance stepping, therefrom optional all 2 branch center points or the some set point resistances got is added the value that is a certain setting and matches, carry out complementary series connection, can effectively overcome like this thermistor because of the large problem of discreteness, with this, overcome the obstacle that high-precision temperature is measured.Two pearl series complementaries can make the central point resistance of measuring temperature reach in full accord, then with and resistance in series compensation, can make again temperature end to end resistance reach unanimously, realize the consistance exchange of the superhigh precision in whole temperature range.The standardization NTC thermistor of obtaining through linearization reforming processing like this, just be particularly suitable for replacing and thisly can only improve to shorten range the instrument of measuring accuracy, as bar type mercury thermometer total length 540mm, scale is always apart from 450mm, just can only carve 500 reticules, if 5 ℃ of ranges are 0.01 ℃ of scale precision, 0.1 ℃ of 50 ℃ of range accuracy.Like this only rely on shortening range to make High-precision Thermometers, this exactly just in time can give full play to, and the existing volume of thermistor is little, variation is large, brief miniaturization and the cheap advantage of can realizing again of circuitry, thereby cracked nearly half a century electronics temperature instrumentation, be difficult to replace the difficult problem of accurate mercury thermometer, from source, remove the mercury pollution in thermometric field.
Accompanying drawing explanation
Fig. 1 is two pearl series complementary structural representations in the superhigh precision digit thermometer of the accurate mercury thermometer of replacement.
Fig. 2 is for two pearls in the superhigh precision digit thermometer of the accurate mercury thermometer of replacement are complementary and series compensation structural representation.
Embodiment
For technological means, creation characteristic that the utility model is realized, reach object and effect is easy to understand, below in conjunction with concrete diagram, further set forth the utility model.
The superhigh precision digit thermometer that replaces accurate mercury thermometer, it has: with the supporting body forming such as shell structure, the printed circuit board (PCB) that is installed on supporting body; Be installed on the temperature detection device of supporting body, itself and printed circuit board (PCB) are electrically connected; Be connected to the display device of printed circuit board (PCB), such as liquid crystal display.
Under the quite ripe condition of current electronic technology, realize high-precision thermometric and measure, most critical be the selection to sensor temperature-sensing element (being previously described temperature detection device).From numerous electronic temperature sensing elements, the three advantages that NTC thermistor can have is that other electronic temperature sensing element is incomparable.
One of NTC thermistor advantage is: volume is little, Φ 1.4*4mm.
Two of NTC thermistor advantage is: highly sensitive, 503ET temperature resistance variation of every 1 ℃ in the time of 0 ℃ is 8000 Ω, is more than 20,000 times of platinum resistance 0.39 Ω.
Three of NTC thermistor advantage is: price is low, and mono-price of 503ET is 0.5 yuan.
But its large this two large defect of the poor and discreteness of existence and stability all of general thermistor, can only rest at present in the narrower occasion of low precision and warm area and apply.If thermistor will be applied in high-acruracy survey thermometric, its first certainly condition is to possess good stability and repeatability.Thermistor came out as far back as the sixties in last century, but the poor disadvantage of existence and stability really, until the nineties, along with the extensive application of electronic thermometer, the improvement on technique and material has had stability to increase substantially.Japan stoneman company is the company of largest production thermistor in the world.In product quality, account for and have great advantage, therefore the 503ET thermistor that the first-selected the said firm of the utility model produces, and require it that product that is all better than platinum resistance index at stability and repeatability index is provided, in the actual test of going through two months, the Surveillance structure that stoneman company provides show its error only for platinum resistance 1/7th less than (referring to table one).
Table one interchanged type standardization thermistor and platinum resistance performance comparison sheet
Note: 503ET R
0=161.9K Ω R
0± 0.1%=161.9 Ω
R
11 ℃ of difference=8000 Ω 161.9 Ω=0.02 ℃ of=153.9K Ω
Having had stability and repeated Reliable guarantee, is that the utility model needs emphasis to solve the large problem of thermistor resistance discreteness with that.With following two kinds, making its resistance realize normalized compensation technique now effectively realizes and surmounts the accuracy requirement of various mercury thermometers to different temperatures range.
Table two 503ET thermistor ± 3% resistance discreteness temperature error table
? | 0℃ | 25℃ | 50℃ | 75℃ | 100℃ |
503ET central value | 161900Ω | 50000Ω | 17930Ω | 7198Ω | 3142Ω |
+ 3% resistance | 168700Ω | 51500Ω | 18660Ω | 7559Ω | 3327Ω |
-3% resistance | 155100Ω | 48500Ω | 17210Ω | 6848Ω | 2964Ω |
+ 3% departs from central value | 6800Ω | 1500Ω | 730Ω | 361Ω | 185Ω |
+ 3% causes temperature error | 0.85℃ | 0.7℃ | 1.07℃ | 1.47℃ | 1.83℃ |
-3% departs from central value | 6800Ω | 1500Ω | 720Ω | 350Ω | 178Ω |
-3% causes temperature error | 0.85℃ | 0.7℃ | 1.06℃ | 1.43℃ | 1.76℃ |
Note: ± 3% causes 0.7 ℃-1.83 ℃ of temperature error scopes
1 ℃ of warm area difference: 0-1 ℃=8000 Ω between 0-100 ℃, 25-26 ℃=2150 Ω, 50-51 ℃=680 Ω
75-76℃=245Ω,99-100℃=101Ω
1, two pearl series complementary methods
Referring to Fig. 1, described pair of pearl series compensation structure: with the second thermistor R
t1the 3rd thermistor R connects
t2form complementary type temperature detection device.
This pair of pearl series compensation structure is applicable to the wider and higher instrument of precision of range.
Two pearl series complementary methods are to get central value to be multiplied by 2 for standardizing standard value, as while getting 25 ℃, 50K Ω * 2=100K Ω, the thermistor that is ± 3% by a certain amount of discreteness again fixes a point to number stepping in 25 ℃ of calibration cells, after resistance stepping, as long as two thermistors of size are added and equal 100K Ω and can realize two pearl series complementaries while being chosen at 25 ℃, as 48.5K Ω+51.5K Ω=100K Ω, 49K Ω+51K Ω=100K Ω, 49.555K Ω+50.445K Ω=100K Ω etc., in the time of 25 ℃, obtain after in full accord with normalized standard value and can check each point tolerance within the scope of 0-100 ℃, can narrow down to 0-0.035 ℃ (referring to resistance discreteness temperature error table the two pearl series complementaries of table three 0-100 ℃ 503ET) from single 0.7-1.83 ℃
Resistance discreteness temperature error table after the two pearl series complementaries of table three 0-100 ℃ 503ET
Substantially can reach the precision index of bar type mercury thermometer.
2, the complementary also series compensation method of two pearls
Referring to Fig. 2, the described pair of complementary also series compensation structure of pearl: with the 4th thermistor R
t1the 5th thermistor R connects
t2form the first series compensation structure, then this first series compensation structure the 3rd compensating resistance R in parallel again
andand form the second parallel-connection structure, then at the second parallel-connection structure the 4th compensating resistance R that connects again
stringand composition temperature detection device.
This pair of complementary also series compensation structure of pearl is applicable to replace various high precision mercury thermometers.
Although two pearl series complementaries can make range central point resistance reach unanimously, while considering batch production, the inconsistent meeting of B constant of thermistor causes departing from of initial point and terminal resistance.Certainly can in addition complementaryly support punching in when pairing, but it is in full accord really will to reach starting point, mid point, terminal, also must rely on also series compensation resistance to complete, finally make 0-100 ℃ of gamut error be controlled at (referring to temperature error table after the complementary also series compensation of the two pearls of table four 0-100 ℃ 503ET) below 0.006
Temperature error table after the complementary also series compensation of the two pearls of table four 0-100 ℃ 503ET
If match series connection with the thermistor that shortens range and select to be less than 1% discreteness more on this basis, can realize theoretically " zero " error.
The utlity model has stronger specific aim, target is to replace various high precision mercury thermometers, on abundant investigation basis, summarize the large class, 853 of mercury thermometer 13 in temperature specification take respectively basic, normal, high, four temperature provinces of superhigh precision and design four complete machines and 12 conventional temperature specification sensors as representative.Can cover so more than 95% conventional mercury thermometer (referring to table five high accuracy number temperature measurer permissible error).
Table five high accuracy number temperature measurer permissible error
The concrete implementation step of the utility model, that develop in advance is the 0-50 ℃ making with single pearl series compensation method, the digit thermometer that resolving power is 0.01 ℃, examines and determine each point tolerance through Shanghai metrological testing technology research institute and is less than 0.04 ℃.To with two pearl series compensation methods, develop on this basis the complete machine of-40 ℃-+100 ℃ now, can apportion-30-+20 ℃, 0-50 ℃, first three resolving power that 50-100 ℃ of three kinds of sensor replace in seven groups of second-class standards of mercury is 0.001 ℃, the high accuracy number temperature measurer of error ± 0.02 ℃.Continue after the various electronic instrument for measuring temperature that complete again high-temperature region and low-temperature space and make by specific standard, progressively accomplish all standing.
With thermistor, make high precision measuring temperature instrument, also must comparing with respect to the cost performance with product of the same type in specific embodiment, as platinum resistance oil Special temperature measurement instrument, import price is more than 20,000 yuan, but make and at 2000 yuan, with interior, can complete with thermistor, as in measuring accuracy with platinum resistance comparison, also there is clear superiority.As again it compared with second-class standard mercury thermometer, mercury thermometer minimum scale value is 0.1 ℃, its hundred figure place will adopt to be estimated read mode and completes, not only there is interpolation in mercury thermometer, more have other five reading error of not knowing for people's door (referring to table six mercury thermometer temperature measurement error) in practical operation
Table six mercury thermometer temperature measurement error
Note: the 1. temperature-sensing element of above instrument all adopts interchanged type standardization thermistor
2. interchanged type standardization thermistor is more suitable for serving as and is wiredly connected with Internet of Things with wireless telemetering and production standard module
If be the minimum scale value considerably beyond it certainly by every error stack.In price, three second-class standard mercury thermometer prices are 600 yuan, in-30-+100 ℃ warm area, high accuracy number temperature measurer is designed to 3 different warm area specification sensors of 1 complete machine configuration, 300 yuan of complete machines, 80 yuan every of sensors, add up to 540 yuan, also can be lower than mercury thermometer.
The foregoing is only preferred implementation of the present utility model, protection domain of the present utility model is not limited in above-mentioned embodiment, and every technical scheme that belongs to the utility model principle all belongs to protection domain of the present utility model.For a person skilled in the art, some improvement of carrying out under the prerequisite that does not depart from principle of the present utility model, these improvement also should be considered as protection domain of the present utility model.
Claims (1)
1. replace the superhigh precision digit thermometer of accurate mercury thermometer, it has:
Supporting body;
Be installed on the printed circuit board (PCB) of supporting body;
Be installed on the temperature detection device of supporting body, itself and printed circuit board (PCB) are electrically connected;
Be connected to the display device of printed circuit board (PCB);
It is characterized in that, described temperature detection device selects two pearl series compensation structures or two pearl is complementary and series compensation structure, wherein,
Described pair of pearl series compensation structure: form complementary type temperature detection device with the second thermistor series connection the 3rd thermistor;
The described pair of complementary also series compensation structure of pearl: form the first series compensation structure with the 4th thermistor series connection the 5th thermistor, then this first series compensation structure the 3rd compensating resistance in parallel and form the second parallel-connection structure again, then connects the 4th compensating resistance again and forms temperature detection device at the second parallel-connection structure;
Wherein, the pass between the second thermistor and the 3rd thermistor, the 4th thermistor and the 5th thermistor is:
The central value R of the second thermistor and the 3rd thermistor is multiplied by 2 for standardizing standard value, as get temperature while being T degree Celsius, central value R*2 is standardizing standard value 2R, the second thermistor is the thermistor of discreteness in-3% scope, and the 3rd thermistor is the thermistor of discreteness in+3% scope;
The central value R of the 4th thermistor and the 5th thermistor is multiplied by 2 for standardizing standard value, as get temperature while being T degree Celsius, central value R*2 is standardizing standard value 2R, the 4th thermistor is the thermistor of discreteness in-3% scope, and the 5th thermistor is the thermistor of discreteness in+3% scope;
Wherein, the resistance of the 3rd compensating resistance is M Ω level;
The 4th compensating resistance is that 1000 Ω are with interior resistance.
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CN105092076A (en) * | 2014-05-17 | 2015-11-25 | 张金水 | Ultrahigh precision digital thermometric indicator replacing precise mercury thermometer |
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CN105092076A (en) * | 2014-05-17 | 2015-11-25 | 张金水 | Ultrahigh precision digital thermometric indicator replacing precise mercury thermometer |
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