- Aug 08, 2017 -
(1) the measurement of objects, such as the physical and chemical properties of the measured medium, as well as the working pressure and temperature, installation conditions, the level of change in speed;
(2) measurement and control requirements, such as measuring range, measurement (or control) accuracy, display mode, on-site instructions, remote indication, interface with the computer, security, corrosion, reliability and ease of construction.
Water level commonly used in the water level and selection points are as follows:
A. The float level gauge puts a hollow float in the liquid. When the level changes, the float will produce the same displacement as the level change. The displacement of the float can be measured by mechanical or electrical methods with an accuracy of ± (1 to 2)%. This level gauge is not suitable for high viscosity liquids and has output control and continuous output at its output. In the design of the water purification plant, this level gauge will be used for the level of the collection wells to control the automatic opening and closing of the drainage pump.
B. Static pressure (or differential pressure) level gauge As the liquid column of the static pressure is proportional to the liquid level, so the use of pressure gauge on the reference surface of the liquid column can be measured on the static pressure level. According to the density of the measured medium and liquid measurement range to calculate the pressure or pressure range, and then select the range, accuracy and other performance of the appropriate pressure gauge or differential pressure table. The accuracy of this level gauge is ± (0.5 ~ 2)%.
C. Capacitive level gauge in the container into the electrode, when the liquid level changes, the electrode internal media changes, between the electrodes (or between the electrode and the container wall) capacitance also changes, the capacitance changes and then converted into Standardized DC electrical signals. The accuracy is ± (0.5 ~ 1.5)%.