Method and apparatus for determining viscosity
AssigneeThe Research Foundation of State University of New York
InventorsBenjamin Chu, Harbans S. Dhadwal
Life of this patent
Estimating the term…
Abstract
A capillary viscometer is provided which includes a fiber-optic probe and a phototransistor which produces an output signal as a liquid meniscus falls through the field of view of a detecting fiber bundle. An analog circuit is employed for receiving the signal and starting or stopping a digital counter in response thereto. The circuit includes first and second differentiators and a zero detection portion for detecting zero value outputs from the second differentiator. The counter is started or stopped upon the generation of a triggering pulse at the time such zero value is detected.
Claims17
A capillary tube viscometer comprising:
- a tube;
- a light source for providing light within said tube;
- means for detecting light from said light source;
- means for producing a signal upon the detection of light by said light detecting means;
- first means for differentiating said signal;
- means for generating a triggering pulse when the
- derivative of said signal is substantially peaking;
- a timer;
- and
- means for actuating said timer upon the generation of said triggering pulse.
An apparatus for determining the flow time for a volume of liquid to pass between two points within a tube, comprising:
- a tube;
- a light source for providing light within said tube;
- first and second means positioned adjacent said tube for detecting light from said light source, said first and second light detecting means being positioned a selected distance from each other;
- means for providing a first signal upon the detection of light by said first light detecting means;
- means for providing a second signal upon the detection of light by said second light detecting means;
- means for providing the first derivative of said first and second signals;
- a timer for measuring said flow time;
- means for providing a triggering pulse to said timer when the first derivative of said first signal or said second signal is substantially peaking;
- and
- means for starting said timer when said derivative of said first signal is substantially peaking and stopping said timer when said derivative of said second signal is substantially peaking.
A method for determining the flow time of a liquid between two points within a capillary viscometer tube, comprising:
- introducing a liquid within said tube;
- causing said liquid to flow within said tube in a selected direction;
- introducing light within said tube;
- detecting said light at a first point within said tube;
- detecting said light at a second point within said tube, said second point being a selected distance from said first point;
- generating a first electric signal corresponding to the intensity of light detected as the meniscus of said liquid passes said first point;
- generating a second electric signal corresponding to the intensity of light detected as the meniscus of said liquid passes said second point;
- differentiating said first electric signal to obtain the first derivative thereof;
- starting a timer when said derivative of said first electric signal is at a peak;
- differentiating said second electric signal to obtain the first derivative thereof;
- and
- stopping said timer when said first derivative of said second electric signal is at a peak.
A capillary tube viscometer comprising:
- a tube;
- a light source for providing light within said tube;
- means for detecting light from said light source;
- means for producing a signal upon the detection of light by said light detecting means;
- first means for differentiating said signal;
- second differentiating means for providing the second derivative of said signal;
- means for detecting when said second derivative has a value of substantially zero;
- means for generating a triggering pulse upon the detection of a substantially zero value of said second derivative of said signal;
- a timer;
- means for actuating said timer upon the generation of said triggering pulse;
- and
- a saturation level indicator for indicating whether the output from said first differentiating means is saturated.
Dependencies are inferred from the claim text.