(1) Prevent the instrument from coming into contact with humid gas. The immersion of moisture reduces the insulation of the instrument, reducing its sensitivity, accuracy and stability.
(2) The glass film of the glass electrode pellet is extremely thin and easily broken. Avoid contact with hard objects.
(3) The glass film of the glass electrode should not be stained with oil. If it is accidentally contaminated with oil, it can be washed first with carbon tetrachloride or ether, then with alcohol, and finally with distilled water.
(4) No bubbles are allowed in the potassium chloride solution of the calomel electrode, and there is little crystallization to keep it saturated. If the crystals are too much and the pores are clogged, it is best to refill the new saturated potassium chloride solution.
(5) If the pointer of the acidity meter is severely shaken, the glass electrode should be replaced.
3. Standard buffer preparation
The reagents used in the standard buffers used in the acidity meter are also relatively easy to purify and stable. Commonly used preparation methods are as follows:
(1) Standard buffer of pH=4.00 Weigh 5.07 g of potassium hydrogen phthalate dried at 105 ° C for 1 hour, dissolved in distilled water, and made up to 500 ml.
(2) Standard buffer with pH = 6.88
Weigh 3.401g of potassium dihydrogen phosphate (KH2PO4) dried at 130 ° C for 2 hours, 8.95 g of disodium hydrogen phosphate (Na2HPO · 12H2O) or 3.549 g of anhydrous sodium hydrogen phosphate (Na2HPO4), dissolved in distilled water and dilute to volume. 500ml.
(3) Standard buffer with pH=9.18
Weigh 3.8144 g of sodium borate (Na2B4O7·10H2O) or 2.02 of anhydrous sodium borate (Na2B4O7) in distilled water and dilute to 100 ml.
2. Instructions
(1) Installation
1 The voltage and frequency of the power supply must conform to the data specified on the instrument nameplate and must be well grounded. Otherwise, the pointer may be unstable during measurement.
2 The instrument is equipped with a glass electrode and a calomel electrode. The bakelite cap of the glass electrode is clamped to the small clip of the electrode holder. The metal cap of the calomel electrode is clamped to the large clip of the electrode holder. The height of the two electrodes can be adjusted using the cap screws on the electrode holder.
3 The glass electrode must be immersed in distilled water for more than 24 hours before first use. It should also be soaked in distilled water when not in use.
4 The calomel electrode should be immersed in saturated potassium chloride solution before initial use, and not in the distilled water with the glass electrode. Soak in a saturated potassium chloride solution when not in use or cover the lower capillary of the calomel electrode with a rubber cap.
(2) Calibration
1 Turn the “pH—mv†switch to the pH position.
2 Turn on the power supply and the indicator light will be on and warm up for 30 minutes.
3 Remove the small beaker of distilled water and gently remove the excess water from the glass electrode with filter paper. A well-selected standard buffer solution of known pH is placed in a small beaker. Immerse the electrode. Note that the capillary ends of the glass electrode tip and the calomel electrode are immersed in the solution. Gently shake the small beaker to even out the solution that the electrode is in contact with.
4 Screw the range switch to 0~7 or 7~14 according to the pH of the standard buffer.
5 Adjust the temperature control button so that the temperature indicated by the knob is the same as the room temperature.
6 Adjust the zero point so that the pointer points at pH 7.
7 Press gently or turn the reading switch slightly to lock the switch. Adjust the positioning knob so that the pointer just points to the pH value of the standard buffer. Release the reading switch and repeat until the value is stable.
8 After the correction, do not turn the positioning knob again, otherwise it needs to be re-calibrated. Remove the standard small beaker and rinse the electrode with distilled water.
(3) Measurement
1 Drain the excess water droplets on the electrode or rinse it twice with the solution to be tested, then immerse the electrode in the solution to be tested, and gently rotate or shake the small beaker to make the solution evenly contact the electrode.
2 The temperature of the solution to be tested should be the same as the temperature of the standard buffer solution.
3 calibrate the zero position, press the reading switch, the value pointed by the pointer is the pH of the liquid to be tested. If the pointer reading exceeds the scale when measuring within the range of pH0~7, the range switch should be placed at pH 7~14 and then measured.
4 After the measurement is completed, after the reading switch is released, the pointer must be pointed at pH 7, otherwise it will be readjusted.
5 Turn off the power, rinse the electrode, and soak as described above.
Ø Sophisticated, stylish, modern streamlined design
Ø Inclined cutting and rotary hydraulic actuator technology ensures a stable cut, increasing force of cut, reliability and lengthening life
Ø High speed light guard
Ø Intelligent control LCD display, easily readable, be with 80 memories each containing 99 individual steps
Ø patented blade latch device prevents blade descent in case of emergency
Ø Blade depth adjustment available from outside the machine without the need to remove any cover
Ø Manual foot pedal for pre pressing of clamp to adjust position before clamping
Paper Cutters, Large Paper Cutters, Automatic Paper Cutter
Anhui Innovo Bochen Machinery Manufacturing Co., Ltd. , https://www.innovomachines.com