The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 08, 1981
Filed:
Jan. 21, 1980
Jukka Tervamaki, Helsinki, FI;
Kommandiittiyhtio Finnpipette Osmo A. Suovaniemi, Helsinki, FI;
Abstract
A multi-dose pipette which comprises a body constituting the handle portion, a cylinder portion or piston chamber with a tip tube, fitted at the bottom end of the said body, a main piston fitted into the cylinder portion or piston chamber. The main piston can be pressed down by means of a press knob and a piston rod against the spring force of a spring and is by a spring returned to the upper position. In addition to the main piston, the pipette also comprises a dose piston with its piston chamber. The maximum stroke volume of the main piston is essentially larger than the stroke volume of the dose piston. The piston chamber of the main piston and the dose piston are connected to each other by means of a channel. The end of the piston chamber of the dose piston facing towards the piston rod is provided with a valve which is fitted so that it opens itself and admits air through the valve into the piston chamber at the upper position of the dose piston. The other end of the piston chamber of the dose piston is provided with a counter-valve which is fitted so that it opens itself and admits air through the valve from the piston chamber of the dose valve into the piston chamber of the main piston at the lower position of the dose piston. By means of repeated movements of the dose piston it is possible to pump precise doses of air into the piston chamber of the main piston. Correspondingly, subsequent liquid quantities of equal relative magnitude escape from the tip vessel.