数字压力式水位仪观测误差与测试方法

Observation Error and Test Method of Digital Pressure Type Water Level Instrument

数字压力式水位仪误差来源于压力测量误差、水密度取值误差和重力加速度取值误差,其中后两者引起的误差与水柱高度有关。对我国地震井水位观测网的水密度和重力加速度取值误差进行分析,大部分观测井水密度和重力加速度取值误差引起的水位观测误差基本上可以忽略。为了减少仪器的观测误差,水位传感器投放深度不宜过深,水位观测井筒水温不宜过高。对于个别矿化度大、富气泡的观测井和水温较高的非自流井,密度影响不容忽视。最后,对近几年来招标采购的水位仪器的测试情况进行总结,认为采用压力输入法与模拟井孔法相结合来测试压力式水位仪器的观测误差更为科学和准确。

The observation error is derived from the pressure measurement, water density, and gravity acceleration error. The errors caused by the density and acceleration of gravity is related to the height of the water column. Error analysis results of the water density and gravity acceleration of the water level observation network in China show that the observation error caused by the error of water densi- ty and gravity acceleration can be ignored for most of the observation well. In order to reduce the measurement error of the instrument, the water level sensor should not be too deep, and water tem- perature in the observation well should not be too high. The influence of density cannot be ignored for observation wells with a high degree of mineralization and rich bubbles, and non-artesian wells with high water temperature. Finally, the testing situation of the water level instrument for many years is summarized. In the last few years the test method combining pressure input and simulation wells to test the observation error of net pressure type water level instrument is more scientific and precise.