Inventors:
Bikash K. Chatterjee - Fremont CA
Steven N. Buhl - Cupertino CA
Thuy N. Tang - San Jose CA
Gary L. Smith - Walnut Creek CA
Bhaskar Bhayani - Fremont CA
Anthony Alvarado - San Jose CA
Swee Wong - San Jose CA
Assignee:
Abaxis, Inc. - Sunnyvale CA
International Classification:
F25D 2502
Abstract:
The present invention provides methods and devices for freezing drops of liquid reagent solution in a cryogenic liquid. In one embodiment, the apparatus of the present invention comprises means for dispensing uniform, precisely measured drops of a liquid reagent and a rotatable carousel positioned below the dispensing means. The upper surface of the carousel has a plurality of trays each containing a cryogenic liquid, typically liquid nitrogen, for receiving the drops of liquid reagent. An alternative embodiment of the present invention comprises a tank comprising a cryogenic liquid for receiving the drops of liquid reagent. The tank has a heat source for slightly heating a portion of the cryogenic liquid such that a convection current in the cryogenic liquid is created. The convection currents in the cryogenic liquid provide mild agitation of the liquid and prevent aggregation of the frozen drops.