HI97725 อุปกรณ์วัดคลอรีน กรดไซยานูริกและ pHในน้ำ จาก Hanna

The HI97725 meter measures four important parameters in the treatment and disinfection of swimming pools, spas and cooling towers. HI97725 measures free and total chlorine, pH and cyanuric acid. Each plays a very important role in the treatment of water.

Chlorine is a commonly used for its disinfection properties. The effectiveness of the free chlorine is pH dependent. As pH decreases less than 7.4 the chlorine is found as hypochlorous acid and when pH increases above 7.4, chlorine is predominantly in the hypochlorite ion form.

Hypochlorous acid is 100X more effective at killing bacteria than hypochlorite. The chlorine method is an adaptation of the US EPA Method 330.5, DPD Colorimetric Method while the pH is an adaptation of the Phenol Red Method. For chlorine and pH, when the appropriate reagent is added to the sample, is a color change will occur. The greater the concentration, the deeper the color.

Up to 90% of the chlorine can be broken down by sunlight in a matter of hours. Adding cyanuric acid to the water stabilizes the chlorine which will slow down the breakdown process. The cyanuric acid is measured by a turbidimetric method.

For cyanuric acid the cloudiness of the sample is dependent on the concentration. The associated color/turbidity change is colorimetrically analyzed according to the Beer-Lambert Law. This principle states that light is absorbed by a complementary color, and the emitted radiation is dependent upon concentration.

For determination of all four parameters, a narrow band interference filter at 525 nm allows only green light to be detected by the silicon photodetector and omits all other visible light emitted from the LED lamp.

As the change in color/turbidity of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases.

 

Specification HI97725

⦁ pH Range 6.5 to 8.5 pH
⦁ pH Resolution 0.1 pH
⦁ pH Accuracy ±0.1 pH of reading at 25°C
⦁ pH Method adaptation of the Phenol Red Method
⦁ Free Chlorine Range 0.00 to 5.00 mg/L (as Cl2)
⦁ Free Chlorine Resolution 0.01 mg/L
⦁ Free Chlorine Accuracy ±0.03 mg/L ±3% of reading at 25°C
⦁ Total Chlorine Range 0.00 to 5.00 mg/L (as Cl2)
⦁ Total Chlorine Resolution 0.01 mg/L
⦁ Total Chlorine Accuracy ±0.03 mg/L ±3% of reading at 25°C
⦁ Chlorine Method adaptation of US EPA Method 330.5, DPD Colorimetric Method
⦁ Cyanuric Acid Range 0 to 80 mg/L (as CYA)
⦁ Cyanuric Acid Resolution 1 mg/L
⦁ Cyanuric Acid Accuracy ±1 mg/L ±15% of reading at 25°C
⦁ Cyanuric Acid Method adaptation of the Turbidimetric Method
⦁ Photometer/Colorimeter Light Source LED with 525 nm bandpass filter
⦁ Photometer/Colorimeter Light Detector silicon photocell
⦁ Bandpass Filter Bandwidth 8 nm
⦁ Bandpass Filter Wavelength Accuracy ±1.0 nm
⦁ Cuvette Type round 24.6 mm diameter (22 mm inside)
⦁ Function GLP
⦁ Display 128 x 64 pixel B/W LCD with backlight
⦁ Logging Memory 50 readings
⦁ Battery Type/Life 1.5 V AA Alkaline (3 pcs.) / > 800 measurements (without backlight)
⦁ Automatic Shut-Off after 15 minutes of inactivity (30 minutes before a READ measurement)
⦁ Environment 0 to 50°C (32 to 122°F); 0 to 100% RH (IP67)
⦁ Weight 380 g (13.4 oz.)
⦁ Dimensions 142.5 x 102.5 x 50.5 mm (5.6 x 4.0 x 2.0″)