Jet adjustment means for fluid jet deflection type instruments

Claim 1

A fluid jet deflection type instrument comprising: a body having a jet chamber, nozzle means having a nozzle for directing a fluid jet endwise of said jet chamber, sensing means disposed in said jet chamber remote from said nozzle and symmetrically relative to the axis thereof and adapted to respond to deflection of a fluid jet from a centered condition relative thereto, said body having exhaust means beyond said sensing means from said nozzle for exhausting fluid from said jet chamber, means for supplying fluid under pressure to said nozzle including a plenum chamber having the intake end of said nozzle opening into the same and fluid inlet means for introducing fluid into said plenum chamber substantially symmetrically about the axis of said nozzle, and means for centering a fluid jet discharged by said nozzle onto said sensing means, said means comprising a plurality of elements extending into said plenum chamber between said nozzle and said inlets for obstructing the flow of fluid through said plenum chamber to said nozzle, and means for adjusting said elements individually for varying the obstruction provided by the same in the plenum chamber.