COD reflux digestion instrument

The standard microcrystalline COD digester uses a glass burr reflux tube instead of a spherical reflux tube and air cooling technology instead of tap water cooling. The cooling part is mainly completed by a burr condenser tube and a fan. The upper part of the condenser tube is spherical, and the catalyst is added from here to prevent the instantaneous evaporation of light components in the sample. The lower part is "burr" shaped, with three opposing spherical condenser tubes extending from the condenser tube wall on a plane. In addition, the dual effect of cooling water and fan in the upper spherical reflux tube ensures the reflux cooling of the sample.

The COD reflux digestion instrument has formulated the measurement steps for the chemical oxygen demand COD (Cr) of water quality in accordance with the standard analysis method of the Ministry of Environmental Protection of China. The method strictly specifies the conditions and indicators such as heating digestion time, solution acidity, oxidant and catalyst dosage. It is obvious that the determination of COD (Cr) in water quality has strict conditions, and any operation that violates these conditions will affect the accuracy of the determination. It follows the basic principles of international standards (ISO) and national standards (GB), ensuring a digestion operation with reflux heating and micro boiling for 2 hours. The preparation and addition of reagent solutions are consistent with the dichromate method of the Ministry of Environmental Protection (HJ828-2017), ensuring reliable and accurate analysis results.

The COD reflux digestion instrument mainly consists of four parts: the body, reflux tube, fan, and microcrystalline heating plate. It uses microcomputer PID technology to control the heating of the electric furnace plate and fan in a timed manner, and can simultaneously heat eight conical flask reflux devices. The chemical solution preparation, operation, and COD calculation of the instrument follow the (HJ828-2017) dichromate method. For COD water samples below 50mg/L, the accuracy can be improved by diluting the titrant and oxidant. For COD water samples above 1000mg/L, the determination can be completed by diluting the water sample proportionally.

Characteristics of COD reflux digestion instrument:

1. Uniform heating: The heating element uses isostatic high-purity graphite with thermal conductivity * to ensure temperature uniformity between each digestion hole, with a temperature difference between holes of less than ± 3.0 ℃.

2. Energy saving and efficient: Adopting the * heating and insulation method, it saves more than 30% energy compared to similar products. Up to 20 samples can be processed simultaneously, greatly improving work efficiency.

3. Accurate temperature control: PID parameter self-test, adjustable heating rate, temperature control accuracy ± 0.1 ℃, single hole temperature fluctuation ± 2.0 ℃.

4. Program control: Large screen LCD intelligent program temperature control, realizing program heating and controlling heating holding time, automatically stopping heating after completing the heating program. Up to 100 heating programs can be set.

5. Anti corrosion design: Graphite thermal conductive material, using special high-temperature PTFE coating as the protective layer of graphite, the surface is not afraid of strong acid and alkali corrosion, and the temperature can reach 260 ℃. The connecting components are made of anti-corrosion materials, and the chassis is treated with anti-corrosion spray coating to resist harsh corrosive environments.

6. Temperature correction: Designed with temperature parameter correction, the temperature probe accurately detects temperature changes and can correct the displayed sample reaction temperature, achieving what you see is what you measure (the temperature displayed on the temperature control panel is the actual sample reaction temperature).