US 6,474,182 B2 · Methods and apparatus for determining the location of a shaft within a vessel

Abstract

Apparatus and methods for measuring the amount by which the centerline of a shaft disposed in a vessel is offset from the central vertical axis of the vessel, and for measuring the height of such shaft above the inside bottom of the vessel. Apparatus includes a shaft centerline offset measurement device, a shaft height measurement device, and a control/display console. Each measurement device includes a transducer or optical encoder for sensing a displaced position of a biased plunger to which a code strip is mounted. The devices may be combined into a single shaft offset and height measurement device. Improved methods include calculating shaft offset based on a plurality of readings from the transducer, and applying trigonometric relationships. The apparatus and methods are particularly useful in the verification of paddle or basket shafts utilized in dissolution testing stations, so that the dissolution testing protocol complies with government agency guidelines.

Claims28

Dependent claims

An apparatus mountable to a shaft having a paddle or basket disposed within a vessel, the vessel having a central axis and a hemispherical end region, the apparatus adapted for measuring the distance from a distal surface of the paddle or basket to a lowermost point on the inside surface of the hemispherical end region and comprising:

(a) the housing comprising a rear face, a top face, and a coupling component for coupling the housing to the shaft, the coupling component comprising a longitudinal recess and a clip, wherein the longitudinal recess is defined by a recess wall extending inwardly toward an interior of the housing from the rear face, the longitudinal recess comprises an upper section extending downwardly from the top face, the upper section has a width greater than a width of an adjacent section of the longitudinal recess, and the clip extends outwardly from the recess wall within the upper section and comprises a pair of resilient prongs;
(b) a plunger slidably mounted to the housing, the plunger having an outer section extending outwardly beyond a wall of the housing, means for biasing the plunger outwardly, and an end portion extending transversely from the plunger beneath the housing and substantially centered about a central portion of the housing;
(c) a transducer operatively mounted to the housing and adapted to encode positions of the plunger and to produce an electrical signal proportional to a change in position resulting from displacement of the plunger;
and
(d) means for transferring the signal away from the housing.

2 more elements

Dependencies are inferred from the claim text.

Methods and apparatus for determining the location of a shaft within a vessel

Life of this patent

Methods and apparatus for determining the location of a shaft within a vessel

Life of this patent

Abstract

Claims28