a face plate 24 having an outwardly extending fluid inlet 26 and an associated inlet chamber 28 the inlet chamber 28 communicates with a plurality of inlets 29 to the interior of the casing 10 which are typically formed in the inner portions of an end plate 30 secured to the peripheral edges of the casing 10 by peripherally spaced threaded fasteners 32 the casing 10 and plate 30 thus define a rotating fluid chamber a pair of spaced apart annular flat plates 34 and 36 are secured in parallel spaced relation to the inner surface of the end plate 30 by appropriately disposed threaded spacer elements 38 the plates 34 and 36 are positioned in coaxial relation about the shaft 12 a rotary seal element 40 is disposed between the outer surface of the internal shaft 12 and the inner annular edge of the annular flat plate 34 to insure that the incoming fluid moves radially outwardly to enter the chamber 11 within the internal chamber 11 of the rotatable casing 10 there is disposed a pitot tube or pick up element 42 which includes a radially extending arm portion 44 and a generally circumferentially extending head portion 46 on the outer end of the arm 44 the pickup element 42 is integral with or stationarily mounted with respect to the discharge tube 12 and has an internal passageway 48 in communication with the interior of the hollow tube 12 the.