{HEAD ~ The present invention} relates to {TAIL ~ a valve} for providing an adjustable loss of head by means of a mobile perforated plate which slides over a stationary perforated plate 
relates to
{ HEAD ~ The present invention } relates to { TAIL ~ a valve } for providing an adjustable loss of head by means of a mobile perforated plate which slides over a stationary perforated plate
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH