Patent ID: 7310046

Claim:
Apparatus to eliminate back scatter pick up by a flow meter from a cloud of particulate dust at the delivery end of an output duct comprising: a first hollow conduit forming a flow path along which solid particulate matter moves and having a delivery end; a second hollow conduit joined to the first conduit at an angle; at least one sensor apparatus associated with said second hollow conduit, said at least one sensor apparatus including: a transmitter of electromagnetic energy for radiating the entire particulate matter flow path formed by said first conduit such that the flowing particulate matter generates back scattered energy; and a receiver for receiving such backscattered energy and generating an electrical signal that is proportional to the amount of solid particulate matter flowing in said first hollow conduit; a processor coupled to said at least one sensor for generating an output signal representative of the flow rate of said solid particulate matter; and a sheath surrounding the delivery end of the first hollow conduit that reflects said back scattered energy to reduce sensing back scatter energy from particulate dust outside of said first hollow conduit at said delivery end.