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:
Apr. 14, 1981
Filed:
May. 15, 1979
Christopher D Shelton, London, GB;
Frenshore Ltd., London, GB;
Abstract
A liquid drop rate controller for controlling flow of fluid from an infusion fluid reservoir to an intravenous infusion site which includes a cam means in the form of a wheel mounted eccentrically on a shaft which varies the compression on a flexible tube carrying the liquid; the controller senses the actual drip rate optically and compares this to a preselected desired drip rate and varies the compression accordingly. The comparison is accomplished electronically by the generation of a time base whose frequency is controlled by the selected drip rate; this time base is compared to the actual drip rate observed by the optical sensing means, and the cam means is controlled in relation to an error signal obtained through the comparison. The controller includes a separate comparison circuit which comes into operation at low drip rates so as to increase accuracy of control.