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. 09, 1986
Filed:
Nov. 28, 1984
Hubert A Wright, Cambridge, MA (US);
Cambridge Applied Systems, Inc., Cambridge, MA (US);
Abstract
A viscometer (10) employs a tube (12) with a check valve (30) at one end and a ferromagnetic bobbin (16) disposed inside and freely movable with respect to it. A pair of coils (38 and 40) are alternately energized, causing the bobbin (16) to move against fluid in the tube in one direction, in which the check valve (30) prevents fluid flow, and in the other direction, in which the check valve (30) permits fluid flow within the tube. When the bobbin (16) moves in the direction in which the check valve (30) permits flow, it draws a new sample of fluid into the tube, and the time required for the bobbin (16) to move in the other direction, in which fluid flow is prevented by the check valve (30), is measured as an indication of the viscosity of the fluid. The position of the bobbin is sensed by measuring the mutual inductance between the coils (38 and 40). Preferably, the bobbin (16) is of neutral buoyancy so that operation of the viscometer is substantially insensitive to vibration and to orientation with respect to gravity.