USTER HVI SPECTRUM, Instruction Manual, Page: 22 / 230

USTER
® HVI SPECTRUM
Instruction Manual
Uster Technologies, Inc. Chapter 1
Overview • Page 1-8
7.2 Length/Strength Module
The Length/Strength module optically determines fiber lengths and their
associated uniformity. The elongation is calculated by averaging the
length of distance the fibers will extend before breaking. The strength is
determined by measuring the force that is required to break a sample of
a known mass.
The Length/Strength module of the
HVI SPECTRUM
consists of a
brushing mechanism, an optical system for measuring length and
uniformity, and a clamping jaw system for measuring strength and
elongation.
7.3 Color/Trash Module
The Color/Trash instrument for measuring cotton color (reflectiveness
and yellowness) and trash is located in the Length/Strength cabinet that
also houses the Micronaire Module. A pneumatic-powered automatic
pressure plate that applies a consistent amount of pressure during
testing is located directly above the tray.
When testing is initiated by pressing the two buttons that are mounted
on the tabletop, the pressure plate descends to the test tray. The color
and trash of the sample on top of the color glass are measured.
The
HVI SPECTRUM
system uses two Xenon Lamps to illuminate the
sample during testing. The color components of cotton (reflectiveness
and yellowness) are measured when the light reflected passes through
the filters and is deflected by photo diodes. This reflectiveness is ex-
pressed as a percent reflectance (%Rd). The yellowness is expressed in
Hunter's scale (+b) values. These values are converted into the
equivalent USDA color grade codes that are based on the universal
standards for grading American Upland and/or Pima cottons.
The Trash module is an automated video image processor that measures
the amount of visible leaf or trash in a sample of cotton. The digitized
image produces results for two measurements:
Trash area —the percent of the sample viewing area occupied by
trash.
Trash count —an indication of the number of trash particles
≈
0.01
inch in diameter or larger.