[54] FLUID DISPENSING SYSTEM WITH OPTICAL LOCATOR
[75] Inventors: Fareed Kureshy, Westwood; Ernest W. Long, Concord; Shailendra Singh, Sharon, all of Mass.
[73] Assignee: PB Diagnostic Systems, Inc^ Westwood, Mass.
[21] Appl. No.: 521,364
[22] Filed: May 10,1990
[51] Int. a.' COIN 35/02; G01N 35/06
[52] US. CI 436/47; 436/49;
436/180; 422/64; 422/67; 356/375; 73/864.21;
73/864.211; 73/864.25
[58] Field of Search 73/864.21, 864.24, 864.25;
356/375; 422/63-67, 100,, 68.1, 82.05, 82.08, 82.09; 436/44-49, 179-180
[56] References Cited
U.S. PATENT DOCUMENTS
3,699,348 10/1972 Hocherl 250/218
4,322,216 3/1982 LUlig 23/230 R
4,344,768 8/1982 Parker 23/230 R
4,420,254 12/1983 Smeaton 356/246
4,452,899 6/1984 Alston 436/46
4,478,094 10/1984 Salomaa 73/863.32
4,574,850 3/1986 Davis 141/9
4,586,546 5/1986 Merci et al 141/2
4,846,003 7/1989 Marquiss 73/864
5,008,082 4/1991 Shaw 422/65
FOREIGN PATENT DOCUMENTS
0311440 4/1989 European Pat. Off. .
0341438 11/1989 European Pat. Off. .
58-095262 6/1983 Japan .
61-26867 6/1986 Japan .
Primary Examiner—James C. Housel
Assistant Examiner—David Redding
Attorney, Agent, or Firm—Gaetano D. Maccarone
[57] ABSTRACT
There is described an analytical isntrument for the analysis of fluids such as biological fluids. The instrument includes a fluid dispensing system having a pipette for dispensing fluid test samples and test reagents to assay cartridges. An optical detection system provides a light beam which intercepts a downward travel path of the pipette prior to its reaching the dispense position. Measurement of the intensity of the light beam in conjunction with the position of the pipette enables a controller to indicate the presence or absence of a pipette tip. In addition, interception of the light beam by the pipette initiates a final approach sequence for the pipette to the dispense position above an assay cartridge by a predetermined increment of travel.
7 Claims, 5 Drawing Sheets
160
