Constant-volume liquid feeding metering method and device for COD detection

Abstract

The invention discloses a constant-volume liquid feeding metering method and device for COD detection; the upper end of a metering tube is connected with a piston pump, and the lower end of the metering tube is connected with a multi-way solenoid valve; the tube wall of the metering tube is externally provided with a photometer fixing ring, the photometer fixing ring emptily sleeves the metering tube and can move up and down along the metering tube, the photometer fixing ring is fixedly connected with a liquid level photometer light source emitting module and a liquid level photometer light source accepting module which are symmetric relative to a metering tube center shaft, the photometer fixing ring is horizontally fixedly connected with one end of a horizontal rod, the other end of the horizontal rod is vertically fixedly connected with a laser distance measurement sensor located below the horizontal rod, and the middle section part of the horizontal rod is fixedly connected with a linear stepping motor located below the horizontal rod through a linear stepping motor shaft; a sample valve and a plurality of reagent values of the multi-way solenoid valve are connected with corresponding reagent bottles respectively; the solution volume is arbitrarily given in a metering pipe measuring range, addition of one part of water sample or a reagent can be completed through one-time extraction, and accumulated error of many times of constant-volume liquid taking can be avoided.

Description

technical field [0001] The invention belongs to the field of water quality analysis and environmental monitoring, and relates to water quality detection technology, in particular to COD (chemical oxygen demand) detection technology reflecting water quality, in particular to a constant volume liquid inlet device for COD detection. Background technique [0002] COD is an important indicator to reflect the quality of water quality. It refers to the amount of oxidant consumed by reducing substances in water that are easily oxidized by strong oxidants, and the result is converted into the amount of oxygen (in mg / L). COD reflects the degree of pollution of the water body by reducing substances. The greater the COD value measured in the water sample, the more serious the pollution of the water body by organic matter. The reducing substances in the water include organic matter, nitrite, ferrous salt, sulfide, etc. , COD is also used as one of the indicators of the relative content o...

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Problems solved by technology

[0004] Aiming at the problem of the current accuracy of COD detection for constant-volume sampling and adding reagents, which affects the measurement accuracy of the measured COD value, and the disadvantages of the COD automatic liquid-taking device according to a certain proportion of fixed-capacity mechanical liquid feeding, the present invention A high-precision, dynamic, flexible, and random liquid-feeding measurement method and device for COD detection are proposed. The structure and method are simple and easy to ensure the accuracy of the measured COD value

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