The pipes 19 contain pressurized water, e.g. at 2 4 bar, and the sprayers 21 have respective nozzles 21A directed {TAIL ~ downwards}, i.e. in the opposite direction to {HEAD ~ the flow F1} 
The pipes 19 contain pressurized water , e.g. at 2 4 bar , and the sprayers 21 have respective nozzles 21A directed { TAIL ~ downwards } , i.e. in the opposite direction to { HEAD ~ the flow F1 }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD