Weedscreen cleaners are essential for rural pumping stations pumping water out of dykes. Without them, the pumps would get choked with weeds and pumping performance would fall with the risk of local flooding. It is important that these weedscreen cleaners are kept in efficient operation. The alternative to a weed screen cleaner is an expensive manual intervention to rake out the weeds.
These weedscreen cleaners are usually PLC controlled. It consists of a grab on a travelling bogie. This bogie travels to a pre-determined position, a winch lowers the grab which closes on the weeds and lifts them out. The winch raises, the bogie travels to an unloading dock, the grab opens and dumps the weeds for collection later. We have found that there have been problems with the plc control and its support. When the plc fails, the whole process is dead. The mechanical and electrical equipment remains in good condition, but the process fails.
IDS have a solution for this. We have developed a system where we control both the hoist and bogie travel motors with ABB inverters. We use the plc functionality within the inverters to control the whole system. The inverters communicate with each other and thus removes the need for the external plc. The inverters add a smooth programmable control to the complete system. The weedscreen cleaner works again!
Weedscreen Cleaner Inverter Control Upgrade
Working with the MEICA team at Yorkshire and Humber Drainage Boards we successfully implemented this weedscreen cleaner solution. Here is what Andrew Rawnsley had to say about the project:
“We had a real problem when we lost a programme in the weed screen cleaner PLC. It wasn’t operational which was proving very costly to us. In addition to this a major problem also occurs in flood events. The weedscreen cleaners are sited on the inlet channel of the water course which in flood events are inundated. The water levels rise to such an extent that control and power cables that go through a junction box are submerged, causing problems with plc comms. As the water levels reduce the weedscreen more often than not is choked with debris and since the weedscreen cleaner is unable to operate it reduces the pump station’s ability to disperse the flood water efficiently. This problem has been resolved by removing the junction box and having cables connected directly from the VSD drives in the pump house to the weedscreen cleaner’s motors. The inverter upgrade also offers the facility to operate the weedscreen cleaner manually from a radio-controlled system that has been incorporated into the control circuit. Previously this was achieved by an operating pendant that had to be plugged in at the weedscreen cleaner which was a health and safety issue as the operator would be standing in flood water. The advantage of using a modern VSD over the original, unsupported PLC is in the event of a failure, the inverter can be easily replaced and re-programmed. Between the Yorkshire and Humber Drainage Boards’ MEICA team and Blaise Ford at IDS we devised a method of controlling the weed screeners motion using ABB’s inverter technology. This proved very successful, we worked closely with IDS on this project and I look forward to working with them again.”
In summary, the advantages of inverter control are:
- Failed weedscreen cleaners work again.
- Re-siting of junction boxes above flood levels – allows vital operation in flood events.
- Manual radio control of weedscreen cleaner – allows operation from a safe distance in flood events.
- No reliance on third party software – the control is within the inverters and easily replaced.
- Simple upgrade and quick to install using standard components.
- Smooth control using inverter ramps.
- Electrical equipment housed in the switch room and not exposed.
- Cost effective solution.
Working with IDS
We are keen to repeat the success of this project with other failed weedscreen cleaners. If you would like to discuss our method of Weedscreen Cleaner Control, please contact us on 0115 944 1036 or email [email protected]