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