Method and apparatus for ultrasonic characterization through the thickness direction of a moving web

Patent · Mon Jan 01 00:00:00 EST 2001

OSTI ID:874083

Jackson, Theodore ^[1]; Hall, Maclin S ^[2]

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1. Atlanta, GA
2. Marietta, GA

A method and apparatus for determining the caliper and/or the ultrasonic transit time through the thickness direction of a moving web of material using ultrasonic pulses generated by a rotatable wheel ultrasound apparatus. The apparatus includes a first liquid-filled tire and either a second liquid-filled tire forming a nip or a rotatable cylinder that supports a thin moving web of material such as a moving web of paper and forms a nip with the first liquid-filled tire. The components of ultrasonic transit time through the tires and fluid held within the tires may be resolved and separately employed to determine the separate contributions of the two tire thicknesses and the two fluid paths to the total path length that lies between two ultrasonic transducer surfaces contained within the tires in support of caliper measurements. The present invention provides the benefit of obtaining a transit time and caliper measurement at any point in time as a specimen passes through the nip of rotating tires and eliminates inaccuracies arising from nonuniform tire circumferential thickness by accurately retaining point-to-point specimen transit time and caliper variation information, rather than an average obtained through one or more tire rotations. Morever, ultrasonic transit time through the thickness direction of a moving web may be determined independent of small variations in the wheel axle spacing, tire thickness, and liquid and tire temperatures.

• Research Organization: Institute of Paper Science and Technology, Inc. (Atlanta, GA)
• DOE Contract Number: FC02-95CE41156
• Assignee: Institute of Paper Science and Technology, Inc. (Atlanta, GA)
• Patent Number(s): US 6308570
• OSTI ID: 874083
• Country of Publication: United States
• Language: English

Related Subjects

method
apparatus
ultrasonic
characterization
thickness
direction
moving
web
determining
caliper
andor
transit
time
material
pulses
generated
rotatable
wheel
ultrasound
liquid-filled
tire
forming
nip
cylinder
supports
paper
forms
components
tires
fluid
held
resolved
separately
employed
determine
separate
contributions
thicknesses
paths
total
path
length
lies
transducer
surfaces
contained
support
measurements
provides
benefit
obtaining
measurement
specimen
passes
rotating
eliminates
inaccuracies
arising
nonuniform
circumferential
accurately
retaining
point-to-point
variation
information
average
obtained
rotations
morever
determined
independent
variations
axle
spacing
liquid
temperatures
ultrasonic pulse
moving web
/73/