Sludge removal that starts and stops on its own
A HYKO® sludge level meter watches the sludge in the clarifier, so the discharge valve opens when needed and closes when done.
How it works
At the high level the PLC opens the discharge valve; at the low level it closes it. Illustrative only; confirm setpoints and valve logic at site.
The challenge
In a clarifier, sludge settles at the bottom and must be drawn off before it builds up and carries over into the clear water. Discharging on a fixed timer, or by an operator's judgement, can mean removing sludge too early, too late, or with too much water. The aim was to discharge based on the actual sludge level.
Level-based automation
A submerged HYKO® ultrasonic sensor sends a pulse down through the water and times the echo from the sludge boundary, measuring the interface continuously without sampling. The transmitter turns this into sludge level and passes it to the plant PLC by 4–20 mA, RS485 Modbus or relay. At the configured high level the PLC opens the discharge valve; at the low level it closes it.
Intended operating value
Sludge discharge driven by the real sludge level instead of a timer, with less manual intervention and less clear water lost with the sludge. Built-in data logging and trend curves show how the sludge layer behaves over time.
Why level-based discharge beats a fixed timer
A timer cannot see what is happening in the tank. Measuring the sludge–water interface directly lets the PLC start discharge when the sludge blanket reaches the high level and stop it at the low level, so the clarifier is emptied of sludge, not of clear water.
Key specifications
| Principle | Ultrasonic echo |
|---|---|
| Range | up to 10 m |
| Sensor accuracy | < 0.3% |
| Outputs | 4–20 mA, Modbus |
| Sensor rating | IP68, 304 SS / PTFE |
| Liquid temperature | 0 to 80 °C |
Related services
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