Accurate liquid extracting and metering device and method

Abstract

The invention discloses an accurate liquid extracting and metering device and a method. The device comprises a pump, a valve unit, an electromagnetic stop valve, a liquid storing unit, a testing module, a liquid detector A and a liquid detector B, wherein the valve unit is provided with a liquid inlet passage, a testing passage, a liquid discharging passage and a common passage connected with theliquid storing unit; the liquid inlet passage of the valve unit is connected with liquid; the testing passage is connected with the testing module; the liquid discharging passage is connected with a waste liquid collecting device; the common passage is connected with one end of the liquid detector A by the electromagnetic stop valve, and the other end of the liquid detector A is connected with oneend of the liquid storing unit; the other end of the liquid storing unit is connected with one end of the liquid detector B, and the other end of the liquid detector B is connected with the pump.

Description

technical field [0001] The invention relates to a liquid sampling and measuring system in water quality monitoring instruments in the field of environmental protection, in particular to an accurate liquid taking and measuring device and method. Background technique [0002] The liquid sampling metering device is one of the core components of the water quality monitoring instrument. The accuracy and reliability of the metering device directly determine the accuracy of the test results and the reliability of the instrument. The dexterity of the device determines the reusability, development cycle and cost. At present, there are three main types of liquid sampling and measurement technologies applied to water quality online monitoring instruments: [0003] (1) Use the sensor to sense the momentary flow of the liquid in the conduit, and realize the measurement of the liquid volume by controlling the flow rate and switching time of the pump. The principle is as follows figure 1...

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Problems solved by technology

The device has high sampling accuracy. Various impurities in the sewage will affect the strength of the light signal, but the reliability of the device depends too much on the sensitivity of the light sensor. The volume of the syringe pump is limited, and the volume of the liquid that can be measured is inflexible. Each volume measurement needs a pair of photoelectric sensors, so the structure is complex and the cost is high

[0006] It can be seen that there are obvious shortcomings in the metering devices of the prior art: the simple structure of the device may not measure the liquid accurately; to ensure the accuracy, it is necessary to design a special liquid storage container and add a certain number of sensors, the system is relatively complicated and the reusability is poor

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