Method and device for detecting flow injection type dissolved oxygen meter

Abstract

Disclosed are a flowing injection type oxygen dissolving meter testing method and a device thereof. Said device comprises a pipeline which has a valve and is connected to a water sample and to the intake terminal of a flowmeter, a flowmeter having its outlet terminal being connected to a standard oxygen dissolving meter through a pipeline, a trace flowmeter and a liquid delivery mechanism as well as an oxygen saturation water tank are connected to each other and connected in parallel to the pipeline between the flowmeter and the standard oxygen dissolving meter, wherein the oxygen saturation water tank is also connected to output terminal of a gas source. According to the present invention, a water sample saturated with gas is continuously injected to a water flow having a low oxygen dissolving concentration, then the oxygen dissolving concentration of the water sample saturated with gas is capable of being ascertained by measuring oxygen partial pressure of the gas and temperature of the water sample, with improved veracity of the measured values of an oxygen dissolving meter. The standard water sample generated has a more correct dissolved oxygen concentration, then some disadvantages such as system leakage and system complexity are avoided, and then said standard water sample is more suitable for a site inspection and an online calibration of a oxygen dissolving meter.

Description

technical field [0001] The invention relates to a dissolved oxygen meter inspection method and device, in particular to a flow injection dissolved oxygen meter inspection method and device. Background technique [0002] At present, the existing domestic and foreign dissolved oxygen meter inspection and calibration methods include air calibration method, electrolysis method and standard gas method. [0003] The saturated dissolved oxygen concentration in water corresponding to the air calibration method is about 8000 μg / L, but in the water vapor system of a power plant, the dissolved oxygen concentration during actual measurement is 2 to 3 orders of magnitude lower than that during air calibration. When measuring high-concentration dissolved oxygen, the electrochemical reaction of the sensor will change, causing the response curve of the electrode to bend downward, resulting in a large error when measuring low-concentration dissolved oxygen. That is to say, the accuracy of t...

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Problems solved by technology

[0004] The electrolysis method is affected by factors such as the change of electrolysis efficiency and the by-product hydrogen of the electrolysis reaction, which causes large errors and uncertainties in the electrolysis method

[0005] The device of the standard gas method is too complicated, and the standard gas used for calibration also has a large error, and the standard gas is difficult to purchase and transport, and it is easy to cause system leakage and other factors during the calibration operation, so it is more difficult to use on site. Difficult, big error

[0006] To sum up, there is currently no inspection and calibration method for dissolved oxygen meters that is suitable for on-site use and has good accuracy and reliability.

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