Multistage pitot pump with means for feeding clean fluid to seals

Claim 1

In a multistage pitot pump, the combination of: a generally cylindrical rotary casing rotatable about its central axis, including first and second annular pump chambers longitudinally spaced along said casing; an outer housing surrounding said rotary casing, said outer housing having an inlet port and a discharge port; drive shaft means extending into one end of said housing and rigidly connected to said casing for rotating the same; generally tubular means extending longitudinally in said housing and upon which said casing is mounted for rotation, such tubular means being fixedly mounted on said housing and having an inlet passage therein communicating between said inlet port and said first pump chamber for supplying a fluid to be pumped to said first chamber, said tubular means having a first pitot tube fixedly mounted thereon and extending radially in said first chamber, said first pitot tube having adjacent its outer end a first pitot inlet facing in a direction opposite to the direction of rotation of said casing, and a passage therein communicating between inlet and first pitot inletnd a longitudinal annular passage, said tubular means having a second pitot tube fixedly mounted thereon longitudinally spaced from said first pitot tube and extending radially in said second chamber, said second pitot tube having adjacent its outer end a second pitot inlet facing in a direction opposite to the direction of rotation of said casing, and a passage in said second pitot tube communicating between said second pitot inlet and a longitudinal discharge duct in said tubular means and communicating with said outlet; and fluid seal means in said longitudinal annular passage, including an annular collar fixed to an inner well of said first chamber for rotation with said casing, an annular sealing ring within said collar with a longitudinal clearance therebetween, said sealing ring being supported on said tubular means, said collar having port means communicating between the inner portion of said second chamber and said clearance intermediate its ends.