Wastewater from households and industrial plants contains particles and fibers that cannot be completely retained by the upstream screen filters. These impurities in the water are deposited on the impellers of the pumps, resulting in a reduction in performance and excessive wear of the pump due to so-called clogging. This usually results in time-consuming, costly and labor-intensive maintenance and repair work. This must be avoided.

Intelligent frequency inverters, such as the Danfoss VLT® AQUA Drive, have a backwash (de-ragging) function. This can be triggered in various ways. On the one hand, at fixed times. Of course, it is even better if the function only comes into play when the pump impeller is really dirty. This can be checked by evaluating the current and voltage curves. The VLT® AQUA Drive monitors the power consumption of the connected pump and activates the deragging function when the load envelope curve is exited due to contamination of the pump impeller. It turns the impeller in the opposite direction to loosen any clogging or deposits on the blades. This ensures maximum pump performance, reduces deposits on the impeller and significantly reduces maintenance costs. At the same time, this also reduces maintenance and service costs and significantly increases system availability.

With the deragging function in the VLT® AQUA Drive, users can carry out proactive cleaning. During the commissioning process, you can define when the system should react, e.g. on start command, on stop command, timer-controlled by means of a digital input, by means of serial communication via the control system or using a series of programmable logic rules. All parameters are combined in a group for easier programming.

The deragging function of the VLT® AQUA Drive offers effective protection and maximum operating time.

Deragging. Copyright: Danfoss GmbH