Silicon micromachined compound nozzle

A silicon compound nozzle for guiding fluid flow includes:

• a generally planar silicon flow plate having a plurality of supply orifices formed therethrough arranged generally symmetrically about the center of said flow plate, an annular trough formed on the underside of said flow plate intersecting said supply orifices, and a mesa at the center of said trough;
• a generally planar silicon orifice plate having an exhaust orifice formed therethrough, said orifice plate having a fixed relationship to said flow plate, the opening of said exhaust orifice at the upper side of said orifice plate being aligned with and smaller in lateral extent than said mesa, a raised perimeter wall around said orifice plate, and a reduced thickness shear gap area;
• and
• a portion of said mesa and said shear gap area being aligned, and the region adjacent said mesa and said shear gap area being in communication with said exhaust orifice and said supply orifices.

A silicon compound nozzle for guiding fluid flow includes:

• a generally planar first silicon plate having first, second, third and fourth openings formed therethrough and offset from each other;
• a generally planar second silicon plate having a fifth opening therethrough and offset from said first, second, third and fourth opening in said first silicon plate, said second plate having a fixed relationship to said first plate;
• said silicon compound nozzle having an area of reduced thickness between said fifth opening and each of said first, second, third and fourth openings so as to form a shear gap for fluid flow substantially parallel to the plane of said first and second plates, and so that fluid flow going through said shear gap from said first, second, third and fourth opening collides and exits through said fifth opening;
• said first, second, third and fourth openings being generally rectangular and positioned around a central mesa area, said central mesa area being aligned with said fifth opening in said second plate and said shear gap being defined by the surface of said mesa and the adjacent surface of said second silicon plate, the extent of the shear gap overlap between said mesa and said second silicon plate adjacent said fifth opening being relatively small compared to the size of said fifth opening;
• said first plate including an annular recess around said central mesa, said annular recess being aligned with each of said first, second, third and fourth openings in said first plate, said annular recess in said first plate tapering and decreasing in cross sectional area with increasing distance from said second plate;
• and
• each of said first, second, third and fourth openings in said first plate tapering and decreasing in cross sectional area with decreasing distance to said second plate.