Patent ID: 7628956

Claim:
A sheath flow forming device, comprising: a first container that stores sample fluid and has a supply port that supplies the sample fluid; a second container that stores sheath fluid and has a supply port that supplies the sheath fluid; a sheath flow cell with a sample fluid inlet that receives sample fluid supplied from the supply port of the first container and forms a flow of the received sample fluid, a sheath fluid inlet that receives the sheath fluid from the supply port of the second container and forms the sheath flow by forming a flow of the received sheath fluid around the sample fluid flow, where a body of the sheath flow cell is concentrically disposed around the sample fluid inlet, and an outlet that discharges the mixture of the sheath fluid and the sample fluid, such that the formed sheath flow flows in the sheath flow cell to the outlet; a first syringe pump that supplies a sheath fluid to the sheath fluid inlet and has a first piston and a first cylinder; a second syringe pump that suctions fluid within the flow cell through the outlet of the flow cell and has a second piston linked by a linkage to the first piston and a second cylinder such that the first and second pistons have the same axis and the first piston and the second piston have mutually equal diameters; a third pump that suctions fluid within the flow cell through the outlet of the flow cell; a first drive source that simultaneously drives the first pump and second pump by driving the coupled first piston and second piston, such that a first flow quantity of the sheath fluid supplied to the sheath fluid inlet by first pump and a second flow quantity of the mixture discharged from the outlet by the second pump are equal; and a second drive source that drives the third pump.