Patent ID: 7518720

Claim:
A flow cell to monitor particles in a fluid comprising: a body having a body aperture therethough forming a wall surface; an inlet slit and an outlet slit integral with opposing sides of said wall surface, a flat transition flow area in fluid communication with each said slit, each said flat transition flow area maintaining an at least partial conical nozzle transition disposed therein, said flat transition flow area and said at least partial conical nozzle transition integral with said body; a pair of spaced transparent plates disposed within said aperture, the space between said plates defining a flow channel substantially aligned with each of said slits allowing the fluid to pass therethrough in a laminar manner; and a retainer attached to said body to retain said plates in place, said retainer having a retainer aperture, wherein said body aperture, said flow channel, and said retainer aperture are substantially aligned to allow light to pass therethrough, wherein incoming fluid is received by said flat transition flow area and said at least partial conical nozzle transition before entering said inlet slit to form a laminar flow of fluid that passes through said flow channel to said outlet slit.