CN1045183A - The accurate pen type pH meter of auto thermal compensation - Google Patents
The accurate pen type pH meter of auto thermal compensation Download PDFInfo
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- CN1045183A CN1045183A CN 89101111 CN89101111A CN1045183A CN 1045183 A CN1045183 A CN 1045183A CN 89101111 CN89101111 CN 89101111 CN 89101111 A CN89101111 A CN 89101111A CN 1045183 A CN1045183 A CN 1045183A
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- electrode
- thermal compensation
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- auto thermal
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Abstract
Integrated circuit of a kind of usefulness, and accurate pen type pH meter with auto thermal compensation function, it can be applicable to the micrometric measurement of various pH value of water solution, accuracy of instrument is better than 0.01pH ± 1 word.Owing to adopted novel structure design, glass pH electrode, contrast electrode and electronic circuit are combined into one, and have also adopted 3 (1/2) A/D converter ics, and make the digitizing of pH value with miniature LCD demonstration.The profile of this pH meter is lip pencil, can carry in pen hangs coat pocket, is suitable for environmental protection, field and on-the-spot precision measurement.
Description
The present invention relates to integrated circuit of a kind of usefulness, and accurate pen type PH meter with auto thermal compensation function, it can be applicable to the micrometric measurement of various aqueous ph values, especially be fit to environmental protection, field and on-the-spot precision measurement, give and to carry and use brings great convenience, accuracy of instrument is better than 0.01PH ± 1 word.
At home and abroad the kind of PH surveying instrument is a lot, from the total indicator reading to the numeral, show, to auto thermal compensation, but adopt the instrument of auto thermal compensation in higher laboratory, to use from temperature compensation manually, and the manufacturing cost height, cost an arm and a leg.Some countries have developed pocket and the pen type PH meter that several numerals show in recent years, but the former can only adopt temperature compensation manually, and operate miss is bigger, though latter's volume is very little, but can not carry out temperature compensation, error reaches 0.2PH, therefore can not do precision measurement and use.
The objective of the invention is to provide a kind of usefulness an integrated circuit, and possess the accurate pen type PH meter of auto thermal compensation device, its glass PH electrode, contrast electrode and electronic circuit are combined into one, and profile is lip pencil.It can carry in pen hangs coat pocket, can measure aqueous ph value exactly again, and precision can reach 0.01PH ± 1 word, and cost is extremely low, and stable performance is easy to operate.
Invention is achieved in that with glass PH electrode and Ag-AgCl contrast electrode makes the PH survey sensor, semiconductor diode is made temperature sensor, PH electrode and contrast electrode are formed primary element in solution, its electrode potential inputs to the analog input end of A/D integrated circuit, the signal of temperature sensor is delivered to the reference voltage of integrated circuit and is brought in the converting sensitivity of adjusting the A/D integrated circuit, to offset the influence of solution temperature, reach the purpose of accurate measurement pH value, and show pH value with 4 bit digital.
This instrument can guarantee that one of key of enough accuracy is correctly to select both to meet the requirement of Nai Site (Nernst) formula, the semiconductor diode that is fit to the integrated circuit operating characteristic is made sensor again, and apply a constant working current, utilize diode PN junction forward voltage drop to reach the purpose of fine compensation with the variation of temperature rule.
The invention will be further described below in conjunction with accompanying drawing:
Figure 1A and 1B are the outside drawings of accurate pen type PH meter.
Fig. 2 A, 2B and 2C are the structural drawing of accurate pen type PH meter.
Fig. 3 is the principle calcspar.
Fig. 4 is an electrical schematic diagram.
Accurate pen type PH meter of the present invention by electrode protection cover (1), pocket hook (2), " location " regulator (3), in fill solution replenisher (4), contrast electrode (5), handwriting (6), " slope " corrector (7), power supply (8), switch (9), display circuit (10), glass PH electrode (11), auto thermal compensation device (12), water-absorbing sponge (13) and form.The pocket hook is positioned at the back side of instrument, can hang in the coat pocket as pen, and display is positioned at the instrument front, so that open-air and on-the-spot precision measurement pH value.
Electronic circuit is by glass PH electrode IE, contrast electrode RE and detected solution are formed a primary element, its electrode potential Ux is as the simulation input signal of A/D converter, make the conversion performance of A/D converter meet the Nai Site formula by " slope " corrector R4 that regulates the instrument back side, and show corresponding pH value with numeral.The effect of " location " regulator R5 is to offset the intercept current potential of liquid junctionpotential, phase boundary potential of electrode or the like.The auto thermal compensation device is to provide a suitable continuous current to supply temperature sensor diode line sex work by field effect transistor V1, biasing resistor R7, the reference voltage of A/D integrated circuit is in time being controlled in the variation of diode PN junction forward voltage, the variation of reference point REFLO (being the variation of reference voltage) is adjusted the A/D converting sensitivity with temperature value, reaches the purpose of auto thermal compensation.
At glass PH contact conductor end one Miniature plug is installed, is convenient to this electrode and wears out afterwards or the dismounting and change after damaging.Leave an injection orifice in the lower end of contrast electrode, be convenient to instrument and use through long-term, in replenishing after filling solution and exhausting, to prolong instrument serviceable life.In protective sleeve, post a water-absorbing sponge, be beneficial to electrode activation, be convenient to quick measurement.
The integrated circuit that adopts among the present invention is 3 1/2 monolithic a/d converters of dual integration.After the numerical value of the basic peripheral cell of integrated circuit is determined, circuit just has a fixing sampling integral time (1000 pulse), by to electrode potential Ux forward integration (sampling integration) with to the quadratic integral of reference voltage Uab reverse integral (relatively integration), electrode potential Ux in the sampling time is converted to and the numerical value that relatively accurately is directly proportional integral time, and measure clock pulses number in comparison integral time with counter, just can obtain the digital value relevant with electrode potential (being pH value), the converting sensitivity of circuit changes simultaneously when changing reference voltage.
R1, R2, C2, C3, C4, C5 are the basic peripheral cell of integrated circuit in the electrical schematic diagram, and R1, C2 determine that circuit clock frequency C3 is a reference capacitance, and reference voltage is just remembered on this electric capacity when comparing integration.C4 is an automatic zero set (AZS) electric capacity, and before each work period, automatic zero set (AZS) is once drifted about with the work of eliminating each operational amplifier in the integrated circuit.R2 and C5 are integrating resistor and electric capacity.V2 is a temperature sensor, and V1, R7 provide a suitable constant working current.C1 is for eliminating the filter capacitor of high frequency interference.
Voltage about a stable 2.8V is provided in the integrated circuit chip.Three dividing points have been formed by R3, R4, R5, R6.The Ua point provides the reference voltage of converter, because the actual slope of electrode is not the Nai Site theoretical value, regulates R4 and can make electrode slope obtain proofreading and correct, and promptly determines A/D(mv/pH) converting sensitivity.The Uc point provides adjusts " location " voltage that the electrode zero potential needs.The Ub point is the reference voltage reference point, the reference point is being controlled in variation along with the forward voltage drop of diode V2 when solution temperature changes automatically, promptly adjusting A/D(mv/pH automatically) converting sensitivity, with of the influence of accurate compensation temperature to electrode slope, and with LCD demonstration pH value.
Claims (7)
1, a kind of accurate pen type PH meter of auto thermal compensation is characterized in that:
A, glass PH electrode, contrast electrode and electronic circuit are combined into one, and its profile is lip pencil.
B, adopted futuramic diode auto thermal compensation device.
C, adopt 3 1/2 A/D converter ics, and show with miniature LCD and to make the pH value digitizing.
Detachably change after d, the glass PH electrode damage, fill solution in the contrast electrode and can replenish.
2, according to the described accurate pen type PH meter of claim 1, it is characterized in that by electrode protection cover (1), pocket hook (2), " location " regulator (3), in fill solution replenisher (4), contrast electrode (5), handwriting (6), slope correction device (7), power supply (8), switch (9), display circuit (10), glass PH electrode (11), auto thermal compensation device (12), absorbent sponge (13) and form.
3, according to the described accurate pen type PH meter of claim 1, it is characterized in that linking up with the back side that is positioned at instrument and hang over coat pocket as pen, display is positioned at the instrument front, so that open-air and on-the-spot precision measurement pH value.
4, according to the described electronic circuit of claim 1, it is characterized in that by glass PH electrode IE, contrast electrode RE and detected solution are formed a primary element, its electrode potential U is as the analog input signal of A/D converter, make the conversion performance of A/D converter meet the Nai Site formula by " slope " corrector R4 that regulates the instrument back side, and show corresponding pH value with numeral.The effect of " location " regulator R5 is to offset the intercept current potential of liquid junctionpotential, phase boundary potential of electrode or the like.
5, according to the described auto thermal compensation device of claim 1, it is characterized in that causing and to manage V1, biasing resistor R7 and provide a suitable continuous current for temperature sensor diode line sex work by the field, the variation of diode PN junction forward voltage, in time controlling the reference voltage of A/D integrated circuit, the variation of reference point REFLO (being the variation of reference voltage) is adjusted the A/D converting sensitivity with temperature value, reaches the purpose of auto thermal compensation.
6, according to the PH glass electrode of the described detachable replacing of claim 1 with fill the contrast electrode of solution in can replenishing, it is characterized in that one Miniature plug being installed at glass PH contact conductor end, be convenient to the aging back of this electrode or damage after replacing and leave an injection orifice in the lower end of contrast electrode, being convenient to instrument uses through long-term, in replenishing after filling solution and exhausting, to prolong instrument serviceable life.
7, according to the described electrode protection cover of claim 1, it is characterized in that in protective sleeve, posting a water-absorbing sponge and be beneficial to electrode activation, be convenient to quick measurement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89101111 CN1017933B (en) | 1989-02-24 | 1989-02-24 | Pencil-type precise ph-meter with automatic temp. compensation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89101111 CN1017933B (en) | 1989-02-24 | 1989-02-24 | Pencil-type precise ph-meter with automatic temp. compensation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1045183A true CN1045183A (en) | 1990-09-05 |
| CN1017933B CN1017933B (en) | 1992-08-19 |
Family
ID=4854148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89101111 Expired CN1017933B (en) | 1989-02-24 | 1989-02-24 | Pencil-type precise ph-meter with automatic temp. compensation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1017933B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104380093A (en) * | 2012-01-25 | 2015-02-25 | 赛诺瓦系统股份有限公司 | Analyte sensor |
| CN104990970A (en) * | 2015-06-24 | 2015-10-21 | 中山欧麦克仪器设备有限公司 | Dissolved oxygen sensor with automatic temperature compensating |
| CN105092653A (en) * | 2014-05-23 | 2015-11-25 | 翰信科技股份有限公司 | Detector for detecting sodium hypochlorite concentration |
| CN109187704A (en) * | 2018-09-29 | 2019-01-11 | 嘉善县惠民小学 | A kind of written examination PH tester |
| US10436736B2 (en) * | 2015-12-08 | 2019-10-08 | Endress+Hauser Conducta Gmbh + Co. Kg | Measurement device for measuring a property of a fluid |
-
1989
- 1989-02-24 CN CN 89101111 patent/CN1017933B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104380093A (en) * | 2012-01-25 | 2015-02-25 | 赛诺瓦系统股份有限公司 | Analyte sensor |
| CN104380093B (en) * | 2012-01-25 | 2018-06-05 | 帕克-汉尼芬公司 | Analyte sensor |
| CN105092653A (en) * | 2014-05-23 | 2015-11-25 | 翰信科技股份有限公司 | Detector for detecting sodium hypochlorite concentration |
| CN104990970A (en) * | 2015-06-24 | 2015-10-21 | 中山欧麦克仪器设备有限公司 | Dissolved oxygen sensor with automatic temperature compensating |
| US10436736B2 (en) * | 2015-12-08 | 2019-10-08 | Endress+Hauser Conducta Gmbh + Co. Kg | Measurement device for measuring a property of a fluid |
| CN109187704A (en) * | 2018-09-29 | 2019-01-11 | 嘉善县惠民小学 | A kind of written examination PH tester |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1017933B (en) | 1992-08-19 |
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