Dayu Electronics: 88K Single-Transducer Sludge Level Meter Performance in Coal Washing Ponds
During coal washing operations, monitoring the sludge layer height in settling or thickening tanks directly impacts washing efficiency, coal slime recovery rate, and water recycling efficiency. Improper sludge level control can not only cause turbid water overflow and coal slime loss, but also disrupt the stable operation of subsequent filter pressing and dewatering processes. Traditional manual rod measurement is both hazardous and discontinuous, while low-end ultrasonic instruments often suffer from severe signal attenuation and inaccurate readings due to the high solids content and dense suspended matter in coal slime water.
The 88K single-transducer ultrasonic sludge level meter, specially developed by Dayu Electronics for coal washing pond conditions, delivered a satisfactory performance through on-site testing.
The test was conducted in the thickening tank of a coal washing plant. The coal slime water in the tank had a high solids content, with a foam layer and slight oil film on the surface, and the tank depth was approximately 6 meters. We immersed the sensor of the 88K single-transducer ultrasonic sludge level meter to an appropriate depth below the liquid surface, while the remote transmitter was installed in the control cabinet beside the tank.
Upon power-up, the transducer emitted ultrasonic pulses toward the tank bottom. The signals penetrated the high-concentration suspended coal layer and generated a clear echo at the sludge layer interface. Unlike similar devices that exhibit chaotic waveforms and intermittent signals, the Dayu 88K sludge level meter maintained stable waveforms and sharp interfaces throughout the entire test period. The echo curves clearly distinguished the positions of the clear water layer, suspended layer, and compacted sludge layer, with no false echo interference.
Of particular note is the rationale behind selecting the 88K frequency. In high-solids media such as coal slime water, low-frequency ultrasonic waves offer stronger penetration but insufficient resolution; high-frequency waves provide better resolution but attenuate too quickly to reach the tank bottom. The 88K frequency serves as a reasonable compromise in the mid-frequency range, overcoming the signal attenuation bottleneck in turbid water environments while retaining sufficient layer discrimination capability to clearly capture the slowly rising sludge interface. Over a continuous 48-hour observation period, the sludge level meter achieved repeatability accuracy at the ±1 cm level, with measured data closely matching simultaneous manual comparison results, proving that this solution can fully replace manual measurement.
The sludge level meter transmitter features a remote-mount design, allowing parameter configuration and data display to be performed in a control room away from the tank, shielding operators from the harsh on-site environment. The transducer features an IP68 fully sealed structure, resistant to abrasion and corrosion, capable of withstanding prolonged immersion in coal washing ponds and mildly alkaline water. Built-in temperature compensation and intelligent echo algorithms filter out abnormal signals from foam and bubbles.
Overall test conclusion: The 88K single-transducer ultrasonic sludge level meter fully meets the daily sludge level monitoring requirements of coal washing ponds, providing stable and reliable measurements with easy maintenance. It can effectively guide automatic sludge discharge valve control or manual sludge removal operations, enhancing the operational precision of coal washing plants.
