CN1042608A - PH value of solution mensuration and measuring instrument - Google Patents
PH value of solution mensuration and measuring instrument Download PDFInfo
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- CN1042608A CN1042608A CN 88107613 CN88107613A CN1042608A CN 1042608 A CN1042608 A CN 1042608A CN 88107613 CN88107613 CN 88107613 CN 88107613 A CN88107613 A CN 88107613A CN 1042608 A CN1042608 A CN 1042608A
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Abstract
A kind of pH value of solution measuring method and measuring instrument comprise that the circuit of electrical equipment compositions such as pH value of solution sensor, semiconductor PN temperature sensor, resistance, potentiometer and display is formed.By the potential electrode electric potential difference,, after excess temperature is proofreaied and correct automatically, provide its result, and intuitively show by display according to the relation between electric potential difference that Nernst equation is described and the pH value of solution.
Description
The present invention is specifically related to a kind of measuring method and measuring instrument that is used to measure pH value of solution (pH value).
The pH value of solution measuring technique is widely used in fields such as chemistry, chemical industry, environmental protection, teaching, scientific research, biology, medical science, geology and metallurgy, and its speed of development is also quite rapid.From prior art, the measuring method of pH value of solution and measuring instrument are existing multiple, and the measuring method of up-to-date release and measurement mechanism are Japan.It is the ion transducer that isolated gate FET is constituted for Jap.P. technology Jp60-7355, place electrolyte, by measure the film potential variation that ion activity takes place on dielectric film, measure and the proportional drain current of film potential again, after temperature correction, draw pH value of solution.Yet the used element of this measurement mechanism is more, and it is not too convenient to operate.The circuit that its measuring method is used comprises that division circuit constitutes by mimic channel, and particularly the temperature correction part is easily influenced by ambient temperature, brings measuring error easily.
The objective of the invention is to, overcome above-mentioned shortcoming, propose a kind ofly can carry out temperature correction automatically, again can the simplified measurement process, improve measuring accuracy, also the available digital display mode intuitively shows its measurement result.
Principle of the present invention is, with contrast electrode with to the potential electrode of hydrogen ion sensitivity, insert solution to be measured and constitute a primary element,, utilize again and describe the pH-value that this spy of energy (NernSt) equation that concerns between this electromotive force and the pH value of solution is obtained solution by measuring the electromotive force of primary element.Nernst equation is:
E＝E
O（T）+K·T·pH
E inserts the electromotive force between the potential electrode and contrast electrode in the solution in the equation: T is an absolute temperature, and K is a constant, and pH is the pH-value of solution, E
O(T) be the electrode normal potential relevant with absolute temperature.Find out by Nernst equation, the electromotive force between potential electrode and the contrast electrode, not only relevant with the pH-value of solution, and also also relevant with the temperature of solution.Want accurately to measure the pH-value of solution, just must proofread and correct because the influence that solution temperature produced.Concrete scheme of the present invention is, utilize glass electrode and contrast electrode or the two is formed by it combination electrode, sensor as measurement of ph value, utilize semiconductor pN knot to make temperature sensor, utilize again by resistance, potentiometer, current regulator diode, operational amplifier, double integrator pattern-number integrated package and display device and form the digital measurement of ph value instrument that can carry out temperature correction automatically.Its measuring method is, to by glass electroplax and reference electroplax, or by the two combination electrode of forming, the electric signal that places solution to produce, with by the electric signal that places same solution pN junction temperature sensor to be produced, carry out the algebraically summation operation by operational amplifier, carry out division and A/D conversion then simultaneously, the numeral that provides pH value of solution at last shows.With above-mentioned measuring instrument and measuring method, finish and realize purpose of the present invention.
The schematic diagram appended below in conjunction with the present invention elaborates.
(1) is for by glass electrode and contrast electrode or by the two ph value sensor of forming that combination electrode constituted among the figure, (2) be high input impedance operational amplifier, (3) be potentiometer, (4) be potentiometer, (5) be resistance, (6) are resistance, and (7) are operational amplifier, (8) be potentiometer, (9) be current regulator diode, (10) are semiconductor pN junction temperature sensor, and (11) are resistance, (12) be resistance, (13) be resistance, (14) are operational amplifier, and (15) (are used for instrument testing for switch, when formal the measurement, switch is in " closing " position), (16) are that (1) is display circuit by the A/D conversion circuit that the double integrator pattern-transformation of variables integrated package and Resistor-Capacitor Unit are constituted, (18) be resistance, (19) are resistance.
By Nernst equation and principle of the present invention and concrete technical scheme as can be seen, the variation of solution temperature directly influences the electric potential difference of ph value sensor output, thereby influences the measurement of pH-value.Want accurately to measure the pH-value of solution, just must proofread and correct, promptly to E in the equation detected solution temperature effect
O(T) Xiang correction, and be called the location compensation, to the correction of KTpH item in the equation, and be called temperature compensation.The combination electrode that the present invention is used has the not temperature variant characteristics of its electric potential difference, i.e. E in the solution of certain pH-value of determining
O(T) be the linear function of temperature, its mathematic(al) representation is:
E
O(T)+KTpH
O=constant
PH in the formula
OBe certain pH value of determining, general pH
O=7.The voltage signal of the output signal of ph value sensor (1) and potentiometer (4) carries out the algebraically summation operation at operational amplifier (2), then, the output signal of operational amplifier (2) is carried out the algebraically summation operation with the voltage signal of being exported by operational amplifier (14) relevant with solution temperature at operational amplifier (7), to eliminate E in the Nernst equation
O(T) component of voltage that is produced, thus the location compensation finished.In addition, the some of the voltage signal relevant of operational amplifier (14) output with the detected solution temperature, reference voltage as double integrator pattern-transformation of variables circuit (16), the voltage signal that operational amplifier (7) output is only relevant with the KTpH item is as the tested input voltage of double integrator pattern-transformation of variables circuit.So just can utilize the characteristics of double integrator pattern-transformation of variables circuit, when carrying out A/D conversion, finish tested input voltage and the reference voltage function of being divided by, thereby at cancellation E
O(T) on the basis of the voltage that is produced, cancellation is because solution temperature changes the influence that the KTpH item is caused again, the big error that is caused when avoiding mimic channel to make division arithmetic.Meanwhile, from the signal of double integrator pattern-transformation of variables integrated package output, be can directly drive liquid crystal display cells for the seven segment code signal of display device use, reach the purpose that shows pH value of solution.
The present invention has the successful implementation example, combination electrode is the 65-1 type among the embodiment, high input impedance operational amplifier is made of the operational amplifier of insulated-gate type field effect transistor as input stage, double integrator pattern-transformation of variables integrated package is ICL7106, display device LCD plate 3551, all resistance are metal film resistor in the circuit, and used potentiometer is WW POT.
Advantage that the present invention had and good effect
1, the used parts number of measuring instrument is few, is convenient to manipulate, and method therefor is simple and feasible;
2, the used combination electrode of the present invention has at certain and determines the not temperature variant characteristics of its electric potential difference in the pH-value solution, adds that the present invention carries out temperature from normal moveout correction to the temperature effect item, thereby has both improved the degree of accuracy of measuring, and also can save people's material resources;
3, the used A/D conversion circuit of measuring instrument replaces the mimic channel in the general measure instrument, when finishing A/D conversion, just can finish division arithmetic like this, thereby bring two advantages.Improved the influence of environment temperature on the one hand, also avoided on the other hand because the error that mimic channel is caused when carrying out division arithmetic to measured result;
4, measuring instrument adopts liquid crystal display device, can provide visualized result to measured result.
Claims (5)
1, a kind of pH value of solution measuring method, it is the electric potential difference that places the primary element of solution two electrodes composition by mensuration, according to describing the Nernst equation that concerns between this electric potential difference and the pH value of solution,, provide pH-value again through the correction of solution temperature to the pH-value influence; The invention is characterized in, primary element is made up of contrast electrode and potential electrode, by electrode electric signal that in solution, is produced and the electric signal that places same solution semiconductor PN temperature sensor to be produced, carry out the algebraically summation operation with operational amplifier, be divided by simultaneously then and A/D conversion, thereby provide the pH-value of solution, and be that numeral shows.
2, pH value of solution measuring method as claimed in claim 1, it is characterized in that, with double integrator pattern-transformation of variables circuit, finish simultaneously the A/D conversion of the output signal of operational amplifier, finish the function of being divided by of this signal and the relevant signal of detected solution temperature.
3, pH value of solution measuring method as claimed in claim 1 is characterized in that, before the pH value of solution sensor signal is carried out A/D conversion, and E in this special formula journey of first cancellation moral
O(T) Xiang voltage signal.
4, pH value of solution mensuration as claimed in claim 1 is characterized in that, the reference voltage input of its double integrator pattern-transformation of variables circuit is a voltage signal relevant with the detected solution temperature.
5, a kind of pH value of solution measuring instrument comprises ph value sensor, pN junction temperature sensor, operational amplifier, double integrator pattern-electric elements such as transformation of variables integrated package; It is characterized in that the signal of ph value sensor (1) and the voltage signal of potentiometer (4) carry out the algebraically summation operation at operational amplifier (2), the output signal of operational amplifier (2) is carried out the algebraically summation operation with the voltage signal relevant with solution temperature of operational amplifier (14) output at operational amplifier (7) then.The output signal of operational amplifier (7) is as the tested input voltage signal of biproduct pattern one number conversion circuit, and the part of operational amplifier (14) output signal is as the reference voltage signal of this change-over circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107613 CN1014461B (en) | 1988-11-02 | 1988-11-02 | Measuring method and its instrument for ph value of solution |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107613 CN1014461B (en) | 1988-11-02 | 1988-11-02 | Measuring method and its instrument for ph value of solution |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1042608A true CN1042608A (en) | 1990-05-30 |
| CN1014461B CN1014461B (en) | 1991-10-23 |
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ID=4834704
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88107613 Expired CN1014461B (en) | 1988-11-02 | 1988-11-02 | Measuring method and its instrument for ph value of solution |
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| Country | Link |
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| CN (1) | CN1014461B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565144A (en) * | 2011-01-04 | 2012-07-11 | 上海仪迈仪器科技有限公司 | Achievement device for concurrently measuring conductivity and pH value in the same solution |
| CN104937402A (en) * | 2013-01-25 | 2015-09-23 | 威立雅水务解决方案与技术支持公司 | Ph value measuring device comprising in situ calibration means |
| CN108344844A (en) * | 2017-01-24 | 2018-07-31 | 陈思嘉 | The detection method of solution basicity value |
-
1988
- 1988-11-02 CN CN 88107613 patent/CN1014461B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565144A (en) * | 2011-01-04 | 2012-07-11 | 上海仪迈仪器科技有限公司 | Achievement device for concurrently measuring conductivity and pH value in the same solution |
| CN102565144B (en) * | 2011-01-04 | 2014-11-19 | 上海仪迈仪器科技有限公司 | Achievement device and method for concurrently measuring conductivity and pH value in the same solution |
| CN104937402A (en) * | 2013-01-25 | 2015-09-23 | 威立雅水务解决方案与技术支持公司 | Ph value measuring device comprising in situ calibration means |
| CN104937402B (en) * | 2013-01-25 | 2019-08-06 | 威立雅水务解决方案与技术支持公司 | PH value measuring device including calibrated in situ device |
| CN108344844A (en) * | 2017-01-24 | 2018-07-31 | 陈思嘉 | The detection method of solution basicity value |
| CN108344844B (en) * | 2017-01-24 | 2021-04-02 | 陈思嘉 | Method for detecting alkalinity value of solution |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1014461B (en) | 1991-10-23 |
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