KHCOD-12ZType standardCODDissolving device

countryHJ828-2017The standard analytical method has standardized the development of chemical oxygen demand for water qualityCOD_（Cr）The measurement steps strictly specify the conditions and indicators of the method, such as heating and digestion time, solution acidity, oxidant and catalyst dosage. It is obvious that the water qualityCOD_（Cr）There are strict conditions for the measurement, and any operation that violates these conditions will affect the accuracy of the measurement.

KHCOD-12ZType standardCODThe digestion device follows international standards（ISO）In accordance with the new national standardsHJ828-2017The basic principle ensures reflux heating with slight boiling2The digestion operation for hours, the preparation and addition of reagent solution are all in accordance withHJConsistent environmental standards ensure reliable and accurate analysis results.

The instrument adopts microcomputer technology for timed control of the heating electric furnace, which can12individual250Simultaneously heat the milliliter triangular flask. To achieve the goals of energy conservation, reducing power load, and improving efficiency.

The instrument adopts a glass burr reflux tube instead of a spherical reflux tube, and uses air cooling technology instead of tap water cooling, which can save water and standardize the instrument.

Preparation and operation of chemical solutions for instrumentsCODThe calculation follows the new standardHJ828-2017, lower than50mg/LofCODThe accuracy of water samples can be improved by diluting titrants and oxidants, which is higher than700mg/LofCODWater samples can be measured by diluting them proportionally.

technical specifications

KHCOD-12ZCOD-12Z: Do it12A sample(Triangle bottle with adjustable pressure)

Compliant with national standard: New standardHJ828-2017

Measurement range:5～700mg/L；700mg/L～10000 mg/LDetermination after dilution of water sample

Dissolving time:1Minutes~2hour30Minutes (Users can choose their own heating time)

Measurement error: Potassium hydrogen phthalate standard solution（500mg/L）The relative standard deviation is not greater than5%；

Industrial organic wastewater（500mg/L）The relative standard deviation is not greater than8%

Environmental temperature: ≤ 40℃

Cooling method: The upper inserted burr condenser tube is water-cooled with dual fans for dual cooling.

Number of Dissolved Samples:12individual250mlCone shaped bottle, heated and digested in three rows simultaneously

Heating power: ＜2400W（AC 220V，50HZ）

Heating table: Microcrystalline glass heating table, overall structure of heating plate, overhead heating, easy to remove for replacement and maintenance.

Instructions for using the instrument panel buttons

Instructions for using the instrument panel buttons:

Hair dryer:

Control the opening and closing of the fan.

Set time (timed):

Dissolve time control setting key. The instrument's startup setting time is2hour30minute. Automatically subtract with each press of the setting key10Minutes, measured by standard reflux methodCODIt should be set as2Hour.

start(heating)：

Start control button for digestion, press the 'Start' button to heat and digest the instrument, and start from the set value (such as2At the hour mark, the timer automatically counts down and the heating indicator light is on. When the set time is reached, the instrument automatically stops heating and the heating indicator light goes out. The instrument fan continues to work, assisting in sample cooling, and can be left unattended.

Instrument usage instructions:

Before powering on the instrument, as much distilled water as possible should be added from the water inlet of the reflux pipe(Add from the slanted mouth and soak in undercooled solution)To ensure optimal cooling effect.

Turn on the power switch on the right side panel of the instrument

At this moment, the instrument displays“000 '“111'“222'…“999Finally, the maximum set value of the digestion time is displayed2hour30At the same time, the fan is turned on and the blowing indicator light is on.

Change the digestion time setting value

Press the 'Set Time' button to decrease the resolution time until the final set value is2Hour. Of course, the digestion time value can also be set arbitrarily as needed.

Start reflux digestion

Press the 'Heat (Start)' button, and the instrument will start heating, digestion, and reflux. The heating indicator light will turn on.

End of digestion

After digestion, the instrument displays“000And it flashes, the heating indicator light goes out, and the digestion is complete.

Instructions for using the buttons on the right side of the instrument:

There is a power switch and voltage regulating knob on the right side

1Power switch:

Turn on the power switch, display the number, the instrument enters the preparation state, and the fan starts working.

2Pressure regulating knob:

The voltage regulating knob is mainly used to adjust the heating voltage on the heating plate. The knob runs from left to right0Resistance to150K，0The resistance heating plate heats up at maximum power. When the sample is over boiling, turn the knob clockwise slowly and slightly to reduce the pressure and lower the heating power, allowing the instrument to operate at the optimal boiling state. (Normal knob on)40Location).

Instrument usage instructions:

Before powering on the instrument, as much distilled water as possible should be added from the water inlet of the reflux pipe(Add from the slanted mouth and soak in undercooled solution)To ensure optimal cooling effect. At the same time, ensure that the bottom of the conical bottle contacts smoothly.

The temperature set at the factory is the optimal temperature for testing, and the temperature setting is different for each unit. The constant temperature set is higher than the actual digestion temperature. This is to ensure safety during instrument digestion, and users can use it with confidence. If the boiling situation is too large or poor during actual operation, the pressure reduction knob can be adjusted until it reaches the optimal boiling effect.

KHCOD-12ZType standardCODPacking list of digester