Abstract: An apparatus and method are provided for determining the position of an elongate member such as a shaft in relation to a vessel in which the elongate member operates. The apparatus includes a mounting component adapted for placement over the open end of the vessel, one or more movable plungers, and one or more transducers that interact with the respective plungers. The plungers and transducers are supported by the mounting component and disposed below the mounting component. Thus, upon placement of the mounting component over the vessel, the plungers and transducers reside within the vessel while permitting the elongate member to be disposed at its normal operating position within the vessel. If the position of the elongate member is offset from a predetermined desired position within the vessel, the plunger is displaced by a certain magnitude that is detected by the transducer.

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.