Leland Stanford Junior University

Eldex Laboratories, Inc.

Joseph G Carleton

Richard G Sweet

Reuben Yotam

A solvent delivery system (10) has first and second pistons (92, 94) and cylinders (58, 68) connected to first and second cams (110, 112). The cams (110, 112) each have a ramped portion (150, 162) and an abrupt step (152, 164). The first cylinder (58) is connected to solenoid valves (44, 46, 48) to fill the first cylinder with solvent components during movement of cam follower (104) along ramped portion (150) of the first cam (110). Spring (140) urges the first piston (92) forward into first cylinder (58). Movement of the cam follower (104) over the step (152) of the cam (110) moves the piston (92) forward abruptly to force the solvent components from cylinder (58) into second cylinder (68). Spring (178) urges piston (94) back in cylinder (68). The second cam (112) is reversed relative to first cam (110). Movement of cam follower (106) over abrupt step (164) of second cam (112) moves second piston (94) back abruptly in cylinder (68) to receive and mix the solvent components in the cylinder (68). Movement of cam follower (106) along ramped portion (162) of cam (112) moves piston (94) forward to force the solvent mixture from the second cylinder (68). A third piston (96) and cylinder (74) has a lesser volume than the first and second cylinders (58, 68). A third cam (114) and cam follower (108) move the third piston (96) back in cylinder (74) when second piston (94) moves forward in second cylinder (68). The second cylinder (68) delivers the solvent mixture to outlet (80) and fills third cylinder (74) while second piston (94) moves forward and third piston (96) moves back. The third cylinder (74) delivers the solvent mixture to outlet (80) while the third piston moves forward, the solvent component fills the first cylinder (58) and the first piston (92) and cylinder (58) fill the second cylinder (68). Check valves (60, 72, 78) prevent backflow in the system.

Programmable solvent delivery system and process

Particle analyzing method and apparatus are provided for measuring the intensity of light scattered from a particle as a function of angle. Particles such as biological cells are contained in a stream for travel along a path which includes a scatter line along which the particles pass successively. A beam of collimated monochromatic radiation is directed onto the flow path, and detector means are provided having a radiation acceptance geometry whose projection intercepts the beam along the scatter line. The projected acceptance geometry includes an aperture image located adjacent the scatter line and having a dimension in the direction of travel of the particles which is substantially less than the length of the scatter line such that the angle of scatter radiation detectable by the detector means varies according to the position of the particle along the scatter line. The output from the detector provides a measure of the scatter light intensity versus angle characteristic of the particle.

Growing community of inventors

Palo Alto, CA, United States of America

Joseph G Carleton