Introduction to CA80COD Instrument

Previously, we introduced some information about the instrument, such as application scenarios, advantages, etc. This article will introduce the internal workings of the instrument. Next, let's introduce its internal components and their functions.

Firstly, there is the blue wheel on the left, named Peristaltic Pump. The function of this component is to precisely and contactless transport process samples and reagents by squeezing the hose with a roller. This method can avoid direct contact between the pump body and the liquid, prevent pollution and corrosion, and ensure measurement accuracy. Next to it is the large black module, which is the Liquid Manager/Valve Manifold, the "heart" of the analyzer and integrates multiple solenoid valves inside. It is responsible for precise control of the flow direction, mixing ratio, and timing of water samples, various reagents (such as RB, RN, RK), and standard solutions, and is the core component for achieving complex chemical reactions and measurements. The upper part of the black module is a plunger pump, which provides power for the entire flow system and accurately delivers the liquid to the digestion colorimetric integrated chamber. Responsible for extracting and transporting key reagents such as water samples, potassium dichromate, sulfuric acid, etc. with extremely high precision (microliter level).
The part that connects multiple pipes below is the distribution valve, which has the functions of flow path distribution, precise measurement, and system cleaning. It is the "transportation hub" of the entire analyzer, which precisely controls the flow and on-off of different liquids (water samples, digestion solutions, standard solutions, cleaning solutions, etc.) through internal valve switching. Combined with a plunger pump, it can accurately deliver water samples and various reagents in proportion to the digestion colorimetric integrated chamber, ensuring the accuracy of COD measurement. After each measurement is completed, it will switch the flow path and rinse the entire system with cleaning solution to prevent residual contamination in the next measurement. The top is a syringe, also known as a metering pump. In the analysis process, it is responsible for accurately mixing water samples and reagents in proportion, or accurately diluting high concentration samples, avoiding errors caused by manual operation. Mainly a quantitative function. The right part consists of a digestion tank and two solenoid valves. The upper solenoid valve is responsible for measuring the pump, while the lower one is responsible for pumping the liquid after the reaction is completed to the distribution valve. The middle part is the digestion tank, which is a place for high-temperature digestion reaction of water samples with potassium dichromate, sulfuric acid and other reagents, used to oxidize organic matter in the water. The internal heating element will heat the reaction solution to around 170 ℃ to ensure complete COD digestion. After digestion, the solution will be directly subjected to photometric detection in this chamber without the need for transfer. Its optical window is part of the colorimetric dish, and the light source and detector directly measure its absorbance to calculate COD concentration. Different pipes are connected to different solutions and pumped in.

The upper part of the instrument is the power interface, the real part, and the slot

Unscrew the screws on the upper part to see the power connection part

The above is an introduction to the interior of the instrument