1. Technical data
1,Acceptance
Please check the following device in the instrument box:
portable pH meter 1 computers
The composite electrode 1
short-circuit plug (has been inserted in the instrument back electrode socket) 1
7 DC1.5V batteries (by express delivery is allowed) 4
standard buffer reagent: 1 sets of pH4, pH6.86, pH9.18
use manual 1
product warranty card 1
product certificate in 1 copies
2,Technical characteristics and application conditions of instrument
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Model
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PHB-1
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PHB-4
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Measuring range
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pH:0~14.00pH
mV:±1600mV,
Temperature:0~60℃
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pH:0~14.00pH
mV:±1999mV,
Temperature:0~60℃
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Resolution
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pH:0.01pH,
Temperature:±1℃
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pH:0.01pH,
Temperature:±1℃
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Precision
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pH:0.01pH,Temperature:±1℃
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pH:0.01pH,Temperature:±1℃
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Temperature compensation
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0-60℃Manual compensation
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0-60℃Manual / automatic compensation
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The basic configuration
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E201-C plastic PH composite electrode
The PH standard calibration sample
7 DC1.5V 4 batteries
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E201-C-W plastic PH temperature electrode
The PH standard calibration sample
7 DC1.5V 4 batteries
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Working conditions
environment temperature: 0 ~ 40 ℃ relative humidity: < 85%
for electric power: 1.5V battery /4 Festival
No significant vibration
except without external magnetic field of the earth magnetic field interference
The input impedance: ≥ 1 × 1012 Ω
drift: ≤ 0.01pH ± 1 words / 2 hours
solution temperature compensation range: 0 ~ 60 ℃
The size and weight: 180 * 80 * 30MM (length * width * height) 0.5Kg
power consumption: 2 W
3,The instrument work principle
The basic principle of pH measurement
Measurement of pH value in the water solution with glass electrode as indicator electrode, calomel electrode as reference electrode, when the hydrogen ion concentration in solution (strictly speaking is activity) that the pH value of the solution changes, electromotive force generated between the glass electrode and a calomel electrode with change, and the potential relationship with the following formula:
E pH = 58.16 * * (273+t ℃) /293 (mV)
E: indicates the potential change, the MV unit. (mV)
pH: the pH values of solution.
T: that of tested solution temperature (C).
Indicator electrode used a glass electrode, the electrode, fluoride electrode, silver electrode, the glass electrode is the most widely used. PH glass electrode head is made of sensitive film special, it is sensitive to hydrogen ions, when it is inserted into the test solution, the potential change with hydrogen ion concentration and temperature of the solution. In the solution temperature is 25 ℃, 1 per pH, the electrode potential changes 59.16mV. The theory of slope coefficient which is often said that the electrode.
The commonly used reference electrode for calomel electrode, the potential does not vary with the concentration of hydrogen ions in the solution was changed.
The measurement of pH value is the essence of the measured potential difference between two electrodes. When the potential of a pair of electrodes in the solution of the resulting difference is equal to zero, the measured pH value of the solution is zero potential value pH, it with the glass electrode in the solution of the relevant. The instrument used is composite electrode is composed of a glass electrode and Ag-Agcl electrode consisting of zero position, the pH value of 7 ± 0.25pH.
4,Method of use instrument
Preparation
• open the instrument back battery cover, install 1.5V 4 batteries (note the positive and negative class). Take short plug of instrument electrode socket, plug electrode. Note that the electrode plug should be kept clean and dry before use, should not be pollution.
· power press to open the key, preheat for 5 minutes.
Instrument calibration
Note: this instrument must use 4, 6.86, 9.18, three kinds of standard buffer solution calibration.
In the pH before the measurement, we need to instrument calibration. To obtain accurate measurement results, calibration with standard buffer solution should be accurate and reliable.
Switch on the power, press the "switch" boot.
Unscrew the short-circuit protection pH socket on the cover, access plastic pH composite electrode, the electrode in pure water and clean and dry.
By measuring the pH thermometer buffer solution temperature, pressing the button "∧" or reduce the key "∨" will display the temperature value accurate adjustment.
The location and calibration: pH electrodes immersed in pH6.86 buffer, stir it still be placed, measured value stability, hold down the "calibration" key and do not put, let go when the LCD screen display CAL symbol, to show flashes of 6.86, after a few seconds display End symbols, and then show the pH calibration (this pH is displayed value varies with temperature, such as 25 ℃ showed 6.86, 15 ℃ showed 7.04 of these are numerical, built-in chip set below). Said to complete the calibration and memory.
The slope of calibration of I: remove the PH electrode, pure water and clean and dry, then PH electrodes immersed in pH4.00 buffer, stir it still be placed, measured value stability, hold down the "calibration" key and do not put, let go when the LCD screen displays the CAL symbol, the first display flashing 4, a few seconds after the show End symbol, and then display the pH calibration values, indicating the completion of calibration and memory. After the calibration will automatically display electrode in the linear section of the slope percentage.
The slope of calibration of II: remove the pH electrode, pure water and clean and dry, then PH electrodes immersed in pH9.18 buffer, stir it still be placed, measured value stability, hold down the "calibration" key and do not put, let go when the LCD screen displays the CAL symbol, the first display flashing 9.18, a few seconds after the show End symbol, and then display the pH calibration values, indicating the completion of calibration and memory.
