Deep well water level sensor based on tdr principle and its water level measurement method

Abstract

The invention discloses a deep well water level sensor based on the TDR principle and a water level measuring method thereof.According to the method, a two-core wire is arranged from a water pump to the ground in the axial direction of a pump head pipe, the whole two-core wire is sleeved with an anti-interference sheath, a TDR measuring instrument is connected with the upper end of the two-core wire, the lower end of the two-core wire stretches out of the lower end of the anti-interference sheath, the TDR measuring instrument is vertically installed in a deep well, the lower endpoint of the two-core wire and a TDR data point which is in front of the lower endpoint and smaller than a frequency conversion interference threshold value and has a minimum value are found out, TDR data between the lower endpoint of the two-core wire and the TDR data point is multiplied by the unit length, obtained through calibration, of the two-core wire at intervals, the total length of the two-core wire is subtracted by the length in water, and then the distance from the water surface to a well mouth is obtained.The deep well water level sensor is high in frequency converter interference resistance, high-precision dynamic water level measurement can be realized, maintenance and replacement are both convenient, and the deep well water level sensor is particularly suitable for the deep well where the variable frequency water pump works.

Description

technical field [0001] The invention belongs to the technical field of detection, and in particular relates to a deep well water level sensor based on the TDR principle and a water level measurement method thereof, which can be used for water level measurement in deep wells. Background technique [0002] In the current water level measurement, the float type water level sensor can only measure the presence or absence of water through the switch value. Although the graded float water level sensor can measure the water level at multiple depths, each level of float switch requires two lead wires. The more the leads, the more lead wires; although the existing ultrasonic water level transmitter is easy to use and has high precision, it cannot be used at all in deep wells with variable frequency pumps, dense cables, and variable diameters, and the transmitted signal will be blocked. The cable wrapped around the head tube is blocked. [0003] Although the submersible pressure tran...

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Problems solved by technology

[0002] In the current water level measurement, the float type water level sensor can only measure the presence or absence of water through the switch value. Although the graded float water level sensor can measure the water level at multiple depths, each level of float switch requires two lead wires. The more the leads, the more lead wires; although the existing ultrasonic water level transmitter is easy to use and has high precision, it cannot be used at all in deep wells with variable frequency pumps, dense cables, and variable diameters, and the transmitted signal will be blocked. Cables wrapped around head tubes are blocked

[0003] Although the submersible pressure transmitter can be used for water level measurement in deep wells with frequency conversion pumps with high precision, as the water level deepens, the pressure sensitive part of the pressure transmitter has high packaging requirements. In deep water above 500 meters , sensitive components are easily crushed and water enters, and once the input pressure transmitter is damaged, it needs to be lifted together with the head pipe of the water pump for repair, and then installed back after repairing, but the water pump with a head pipe of more than 500 meters is lifted and reinstalled once The labor cost is far greater than that of an input liquid level transmitter

[0004] The existing water level sensor based on the TDR principle and the water level sensor based on the capacitance principle can be used for water level measurement in an empty well without frequency conversion pumps, but when there is a frequency conversion water pump working, the TDR transmission line or the plate of the capacitance sensor needs to be connected with the frequency conversion water pump. The cables are installed in parallel. When the depth of the well is several hundred meters, the parallel part is also hundreds of meters. When the frequency converter is working, the frequency conversion interference radiated by the water pump cable is far greater than the useful signal, causing the transmission line of the TDR or the capacitance sensor. not working at all

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