Apparatus for drawing liquids into and expelling liquids from a pipet at variable flow rates

(19)

(11)

EP 0 904 840 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	19.01.2000 Bulletin 2000/03

(43)	Date of publication A2:
	31.03.1999 Bulletin 1999/13

(21)	Application number: 98307455.0

(22)	Date of filing: 15.09.1998

(51)	International Patent Classification (IPC)⁷: B01L 3/02

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

30.09.1997 US 60485 P

(71)	Applicant: Becton, Dickinson and Company
	Franklin Lakes, New Jersey 07417-1880 (US)

(72)	Inventors:
	Steele, Timothy Paul Maple Grove, MN 55311 (US) Kenney, James William Broomall, PA 19008 (US)

(74)	Representative: Ruffles, Graham Keith
	MARKS & CLERK, 57-60 Lincoln's Inn Fields London WC2A 3LS London WC2A 3LS (GB)

(54)	Apparatus for drawing liquids into and expelling liquids from a pipet at variable flow rates

(57) A pipet gun for drawing liquids into and dispensing liquids from a pipet which includes a variable flow valve assembly. The valve assembly includes a valve which is capable of accommodating a plurality of flow rates, and which is progressively adjustable during pipetting between a first air flow rate and a second air flow rate which is in excess of the first flow rate and which is non-progressively adjustable during pipetting to a third air flow rate which is substantially greater than the second air flow rate. The valve assembly further includes a threshold detector in the form of a spring detent, which provides an indication to the operator that the pipet gun is operating at the increased fluid rate, i.e., the "express mode" of operation.

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