use of a fluorescent cotton dust tracer for an …
TRANSCRIPT
USE OF A FLUORESCENT COTTON DUST TRACER FOR AN ENGINEERING
ANALYSIS OF DUST EMISSIONS IN EARLY STAGES
OF COTTON TEXTILE MANUFACTURING
by
LAWRENCE GILBERT DANIEL, B.S., B.A.
A THESIS
IN
CHEMICAL ENGINEERING
Submitted to the Graduate Faculty of Texas Tech University in
Partial Fulfillment of the Requirements for
the Degree of
MASTER OF SCIENCE
IN
CHEMICAL ENGINEERING
Approved
Accepted
May 1981
ACKNOWLEDGMENTS
This thesis is dedicated to the memory of Professor Jack D. Towery
who contributed significantly to my understanding of cotton textile pro
cessing.
Major credit for this research effort is ascribed to my trusted
counselor and guide. Dr. Robert M. Bethea, whose direction and advice is
sincerely appreciated. I am deeply grateful to Drs. Philip R. Morey and
Steven R. Beck for their generous help and for the many improvements due
to their suggestions. I also wish, to express my appreciation tc Mr.
Edwin R. Foster and the Textile Research Center at Texas Tech University
for their invaluable aid in process research. I acknowledge with grati
tude the Natural Fibers and Food Protein Commission of Texas for provid
ing the Zeiss Photomicroscope III which played a vital role in this re
search. A special thanks is extended to Mark Drosche for his superb
drawings and to Sue Willis who typed the manuscript with great care and
patience.
Finally my fondest thanks go to my wife Gay; she cheerfully proof
read the manuscript and its many revisions. I was always blessed with
her support and encouragement.
n
TABLE OF CONTENTS
PAGE
ACKNOWLEDGMENTS ii
LIST OF TABLES v
LIST OF FIGURES vi
CHAPTER I INTRODUCTION 1
CHAPTER II LITERATURE REVIEW 3
CHAPTER III METHODOLOGY 9
Determination of Label in Airborne Dust 9
Sieving of Macro Samples 10
Determination of Label in Macro Samples 11
CHAPTER IV ENGINEERING ANALYSIS !4
Problem Definition 14 Engineering Studies 14
Description of the Process 16
CHAPTER V RESULTS AND DISCUSSION 31
CHAPTER VI CONCLUSIONS AND RECOMMENDATIONS 42
REFERENCES 43
APPENDIX 46
CALCULATIONS 47
Feeders and Feed Hoppers 47
Roller 47
Superior Cleaner 48
Impact Cleaner 49
CMG* Cleaner 50
Blade Beater 51
Kirshner Beater 55
Calender Rolls 59
m
TABLE OF CONTENTS
PAGE
ACKNOWLEDGMENTS ii
LIST OF TABLES v
LIST OF FIGURES vi
CHAPTER I INTRODUCTION 1
CHAPTER II LITERATURE REVIEW 3
CHAPTER III METHODOLOGY 9
Determination of Label in Airborne Dust 9
Sieving of Macro Samples 10
Determination of Label in Macro Samples 1!
CHAPTER IV ENGINEERING ANALYSIS 14
Problem Definition 14 Engineering Studies 14
Description of the Process 16
CHAPTER V RESULTS AND DISCUSSION 31
CHAPTER VI CONCLUSIONS AND RECOMMENDATIONS 42
REFERENCES 43
APPENDIX 46
CALCULATIONS 47
Feeders and Feed Hoppers 47
Roller 47
Superior Cleaner 48
Impact Cleaner 49
CMG^ Cleaner 50
Blade Beater 51
Kirshner Beater 55
Calender Rolls 59
m
PAGE
L icker - in 63
Flats and Main Cylinder 63
Doffer and Main Cylinder 65
S l iver 65
TV
LIST OF TABLES
PAGE
Table 1. Forces Exerted and Percentage of Labeled Particles by Size Class in Opening and Cleaning 33
Table 2. Forces Exerted and Percentage of Labeled Particles by Size Class in Picking 34
Table 3. Percentage of Labeled Particles in Respirable Airborne Dust 36
Table 4. Percentage of Labeled Particles in Total Airborne Dust 39
Table 5. Forces Exerted and Percentage of Labeled Particles by Size Class in Carding 40
LIST OF. FIGURES
PAGE
Figure 1. Feeder Section 17
Figure 2. Superior Cleaner 19
Figure 3. Impact Cleaner 20
Figure 4. CMG'^ Cleaner 22
Figure 5. Feed Hopper 23
Figure 6. Blade Beater 25
Figure 7. Kirshner Beater 27
Figure 8. Calender Roll Section 28
Figure 9. Carding 29
Figure 10. Process Flow Sheet 32
VI
CHAPTER I
INTRODUCTION
Cotton dust is defined as "dust present during the handling or pro
cessing of cotton which may contain a mixture of substances including
ground-up plant matter, fiber, bacteria, fungi, soil, pesticides, non-
cotton plant matter and other contaminants which may have accumulated
during the growing, harvesting and subsequent processing or storage
periods" (28). The action of this dust on the human respiratory pas
sages results in the development of byssinosis. The permissible expo
sure limit for cotton dust in textile manufacturing is 0.20 milligram '^
of lint-free, respirable dust per cubic meter of air sampled by the
vertical elutriator.
Although the specific causative agents have not been identified,
toxicological evidence points to the bract of the cotton plant as the
source of the bioactive material (4). In order to verify that bract
and leaf-like materials are major ingredients in respirable cotton dust,
a technique for tracing plant part friability into the respirable range
was needed. It was proposed (17) that fluorescent labeling techniques
be developed for following the breakup of botanical trash components
into respirable cotton dust. The evaluation of that technique in cot
ton ginning (2) and carding (2) has demonstrated the feasibility of
tracing labeled botanical constituents through those cotton processing
operations.
The objective of this research is the evaluation of the feasibi
lity of tracing labeled botanical constituents through the early stages
1
of cotton textile manufacturing. For this purpose, raw cotton produced
as a result of ginning bulk seed cotton incorporating 0.1 weight per
cent cotton leaves labeled with color index basic yellow 37 (BY 37) dye
in the course of previous research (2) was processed through the Textile
Research Center at Texas Tech University. If labeled material, added
to bulk seed cotton before ginning, can be accurately traced through
ginning, opening, cleaning, picking and carding, then this will have
demonstrated the ability to trace labeled botanical constituents through
succeedingly finer micronizations (10). The successful conclusion of
this research will provide a basis for ascertaining the extent of the
presence of leaf-like botanical components, such as bract, in the res
pirable range and thus aid in an engineering analysis of cotton dust
emissions in opening, cleaning, picking, and carding. Separation of the
cotton dust into discrete particle size fractions was accomplished
using a set of U.S. standard testing sieves. Epifluorescence micro
scopy was employed to follow the dispersion of labeled material into
the trash and product streams and monitor airborne particulate matter.
CHAPTER II
LITERATURE REVIEW
The harmful effects of hemp, flax and cotton dust have been observ
ed since the early eighteenth century in French and English textile mills
Evidence that these harmful effects were associated with a progressive
respiratory disease eventually led to English recognition of byssinosis
as a compensable illness (25). McKerrow and Schilling found evidence
in 1960, that byssinosis also existed in the cotton industry in the
United States (14). In 1976, it was estimated by George Perkel that the
prevalence of byssinosis in yarn preparation departments of the U.S.
cotton textile industry effected 20 to 30 percent of the work force (26).
The diagnostic identification of byssinosis is based upon subjec
tive complaints of chest tightness and cough, alone or in cor.::jination
with dyspnea. These symptoms occur most severely upon return to work
after some absence (hence the term "Monday fever syndrome") with sub
sequent reduction in symptoms on repeated exposures (8).
These complaints are frequently accompanied by a decrease in the
forced vita! capacity as measured by FEV,, the forced expiratory volume
in one second. It is believed that these observed symptoms are attri
butable to the action of the dust on the mucous membranes of the respira
tory passages (13).
Although neither the mechanism of action of the dust nor the speci
fic causative agent(s) are known, certain hypotheses have been ad
vanced in an attempt to determine the pathogenesis of byssinosis.
Rylander and Snella attributed the disease to a microbial component,
3
most probably endotoxins. They found that endotoxins, which are a com
ponent of the cell wall of gram-negative bacteria, v/ere responsible for
eliciting a reaction pattern which was similar to that obtained after
exposure to water extracts of micronized bract samples (24). Fischer,
et al. determined that bracts are the source of large numbers of gram-
negative bacteria (7). Bouhuys and co-workers ascribed byssinosis to
cotton dust histamine-!iberating action. They found that the inhalation
of an aerosolized aqueous extract from bracts contained chemical agents
that would release histamine and produce acute symptoms of byssinosis
(4).
While no study has yielded definitive results concerning the path
ogenesis of byssinosis, all implicate cotton bract as a major source of
cotton dust. As convincing as the evidence appears, it may be mislead
ing because of the noticeable lack of control studies on other cotton
plant parts. Apparently bract is preferentially tested because the
evidence presented by Bouhuys and his collaborators, that the bract of
the cotton plant contains an active material causing byssinosis, is
presumed impressive (13). Nevertheless, it has been established that
the prevalence of byssinosis is related to the concentration of lint-
free respirable cotton dust. This dust is composed of particles 15 um
or less aerodynamic equivalent diameter as measured by a vertical elutri
ator or equivalent method (12, 15).
As bract is a major component of botanical trash (6, 17) which in
turn is believed to be micronized into cotton dust during the process
ing of cotton (19), it has been suggested that cotton bract is the likely
carrier of most of the causative agent(s) responsible for byssinosis '13).
In order to verify this supposition, evidence must be presented to
show that bract is indeed micronized into respirable cotton dust during
cotton processing at the textile mill. Unfortunately, bract is not the
only component of botanical trash. Morey and Bethea (17) showed that
leaf material is also present in major proportions in size classes less
than 420 ym in diameter. They also found that bract and leaf are
morphologically indistinguishable in the respirable range and suggested
that fluorescent tracer techniques be used to determine the botanical
origin of particles present in respirable cotton dust (17). Rowlett
was able to show that leaf material, its friability uneffected by dyeing,
was micronized into respirable cotton dust during pilot-scale ginning
by developing techniques to fluorescently label cotton leaves, mix them
in controlled proportions into raw seed cotton, take representative
airborne and spot samples during ginning and evaluate the amount of
labeled material present in those samples (2).
The Occupational Safety and Health Administration (OSHA) has pro-
mu'
lint-free respirable cotton dust for textile manufacturing. At the
time of this writing, the proposed standard for occupational exposure
to cotton dust has been upheld by the U.S. Court of Appeals and is cur
rently under review by the U.S. Supreme Court. Until the causative
agent(s) is identified permitting specific action to be taken, compli
ance will necessitate the development of adequate engineering controls
to reduce cotton dust levels in the working environment. The economic
burden of compliance will be severe. OSHA estimated, in 1978, that
ilgated a standard of 0.2 mg/m permissable exposure limit (PEL) of
the compliance cost for the entire cotton processing industry would be
$656 million in capital and $206 million annually (28). Industry esti
mates are higher (26).
In order to be successful, engineering controls must permit the
capture of cotton dust at the source of generation and the removal of
cotton dust from the air before it is recycled. Recycling conditioned
air is necessary industrial practice in American textile mills for humi
dity and temperature control (11). The principles of engineering anal
ysis (1) lend themselves readily to the preparation of recommended tecn-
nical guidelines for control technology implementation. This involves
technological and economic considerations as to selecting and designing
devices which will meet the control requirements at the lowest annual
ized cost but with maximum reliability expressed over the operating
life of the equipment.
Since it is believed that cotton dust consists largely of the micro
nized portions of botanical trash initially incorporated into the bulk
seed cotton during harvesting (19), then the total trash (or non-lint)
content of the cotton being processed must be of concern to any analysis
of the problem. The amount, distribution and type of botanical trash
depends on the harvesting method, ginning method, variety growing sea
son, soil type, geographic location and cultural practices acting on
plant growth (5, 18, 22). It is reasonable to expect that cotton dusts
in textile manufacturing mills using different sources of baled cotton
will contain different concentrations of trash and thus different con
centrations of the causative agent(s) (21). Therefore the cleaner the
cotton reaching the mill, the greater the chance of reducing dust
concentrations below the hazardous level. Indeed, it has been shown
that steaming a continuous bat of cotton after ginning decreases the
concentration of airborne dust while carding; however this may result
in increased dust levels in spinning (27). This approach to dust pre
vention has also been applied to genetic research (31) and to ginning
(29, 30). Ginning research has shown that the weight percent bract in
creases with decreasing trash particle size (18) and that successive
numbers of lint cleanings generate smaller particle sizes (23). The
visible Shirley trash content in baled cotton varies from less than
1 percent to more than 8 percent with a mean value of 1.6 percent (9)
and steadily decreases as the cotton is processed.
Unfortunately, little is known about the trash levels in each
stage of cotton textile manufacturing. This information, especially as
it relates to respirable dust composition and concentration, would be
an important adjunct to the engineering analysis of cotton dust emis
sions in textile mills.
It has been strongly suggested that hazard at the workplace would
be most accurately measured by concentration of causative agent(s) in
the dust rather than by mass concentration of the dust (3). This is
supported by findings that high concentrations of dust are associated
with a low prevalence of byssinosis in certain non-textile segments of
the cotton industry where raw materials have a low content of leaflike
trash (16).
Bract is thought to be the probable carrier of most of the causa
tive agent(s) responsible for byssinosis (13) and is botanically similar
to dyed cotton leaves added to bulk seed cotton prior to ginning (2).
8
Therefore it should be possible to more accurately predict the byssino-
tic risk, based on the probable carrier of most of the causative
agent(s), by following the micronization of dyed leaf material into
respirable cotton dust during opening, cleaning, picking and carding.
The amount of labeled particulate matter in airborne and spot samples
can be determined using epifluorescence microscopy (2, 20). In turn
this should lead to an improved engineering analysis of dust emissions
in the early stages of cotton textile manufacturing.
CHAPTER III
METHODOLOGY
The fol lowing procedure allows the determination of the percentage
of labeled part ic les in each sample by comparing BY 37-dyed part ic les
to non-dyed par t ic les. This is made possible by thei r difference in
fluorescence. BY 37-dyed part ic les emit a yery bright yellow f luore-
sence when viewed under u l t rav io le t l i gh t whereas the undyed part icles
do not.
Determination of Label in Airborne Dust
Determining the amount of labeled part iculate in airborne samples
is accomplished by using a Zeiss Photomicroscope I I I equipped with both
white l i g h t and long-wave u l t rav io le t i l lumination systems. Vertical
e l u t r i a to r f i l t e r s are placed dust side up on a clean glass sl ide and
a No. 1-1/2 covers!ip is placed on top of the f i l t e r . A 50 gram lead
weight is placed on top of the covers!ip for 30 to 60 seconds and then
removed. With the aid of tweezers, the covers!ip with adherent dust
part ic les on i t s lower surface is transfered to a second clean glass
s l ide for epifluorescence microscopic examination. This procedure is
repeated twice more giving three subsamples per f i l t e r . Total p a r t i
culate (high volume) f i l t e r s are placed dust side up and three No. 1-1/2
covers!ips placed on top of d i f fe ren t , randomly selected areas of the
f i l t e r . The three subsamples are prepared as before. Particles of dust
trapped between the glass sl ide and covers!ip are exposed to ref lected
long-wave u l t rav io le t l i gh t (334 and 365 nm peaks) and fluorescent
10
observations of BY 37-dyed vs. nondyed part ic les are made using a numer
ical aperture 0.75 Zeiss neofluar 40X object ive. F i f ty random f ie lds
are viewed on each subsample. Fields that do not contain BY 37-dyed
part ic les are not counted. The counting procedure for f ie lds contain
ing one or more BY 37-dyed part ic les is as fol lows. Because of the large
number of part ic les per f i e l d , a diameter of the c i rcular f i e l d is ex
tended through each BY 37-dyed part ic le present and the tota l number of
part ic les along each diameter is counted. After a l l f i f t y f ie lds have
been viewed, the ra t io of the sum of a l l labeled part ic les observed to
the sum of a l l part ic les along diameters is recorded. This ra t io is
then mul t ip l ied by the f ract ion of f ie lds containing BY 37-dyed pa r t i
cles to obtain an estimate of the re lat ive amount of labeled part iculate
per subsample. This value is then converted to a pe r - f i l t e r basis.
Sieving of Macro Samples
Part ic le size separations of macro samples are accomplished by the D
use of a Tyler standard sieve series and a Ro-Tap shaker. The series
consists of 10, 14, 20, 40, 60 and 100 mesh sieves corresponding to
1.651, 1.168, 0.833, 0.420, 0.246 and 0.147 mm square openings, respec
t i ve l y . The sieves are arranged in order of decreasing part ic le size.
A catch pan is included under the 100 mesh sieve. Each sample is de
posited on top of the clean 10 mesh sieve. The mass of f iber is care
f u l l y pulled apart for three minutes to dislodge entangled trash mate
r i a l . The l i d is then placed on top of the 10 mesh sieve and the stack
of sieves placed on the Ro-Tap shaker for three minutes. This proce
dure is repeated twice more to give a tota l of three shakings. The
11
contents from the surface of each sieve and the catch pan are then
placed in sample containers. The series of sieves is thoroughly clean
ed by tapping with a soft bristled brush between samples. Each sample
is separated into the sizes shown below:
U.S. Standard Sieves mm
+10 X > 1.651
10/14 1.168 < X ± 1.651
14/20 0.833 < X < 1.168
20/40 0.420 < X £ 0.833
40/60 0.246 < X £ 0.420
60/100 0.147 < X £ 0.246
-100 X < 0.147
The +10 size fraction is that sample retained on the 10 mesh sieve; the
-100 size fraction is that portion of the sample which passed the 100
mesh sieve and is caught in the pan.
Determination of Label in Macro Samples
Because no single viewing method is applicable to the entire size
range of macro samples, it is necessary to divide the size range in
order to accommodate the most efficient viewing method. Particles in
the +10, 10/14 and 14/20 size fractions are viewed against a black back-p
ground under a Blak-ray model B-IOOA mercury vapor, lOOW, long-wave
ultraviolet light source fitted with a Kodak Wratten #18A exciter fil
ter. This ultraviolet source is positioned approximately 20 cm from
the sample to be viewed and illuminates from the side. All extraneous
12
light is eliminated and a visual count made of BY 37-dyed particles;
then all the particles are viewed and counted under incandescent light.
Subsamples are prepared for viewing depending on the number of particles
and amount of lint present. Samples containing less than 300 particles
are viewed in toto. Samples which contain larger numbers of particles
are quartered and opposite-diagonal quarters retained. These two quar
ters are in turn combined and quartered again. This time the other
pair of opposite-diagonal quarters are retained. This continues until
approximately 100 particles remain. The procedure is repeated twice
more to give a total of three subsamples for viewing. Samples which
contain a large amount of lint are spread out on a black background and
a 5.7 X 11.4 cm (2-1/4 x 4-1/2 in.) field layed out at random to provide
a grid for viewing. All particles within this area are viewed. This
procedure is repeated twice more in different, randomly selected areas
of the sample to give a total of three subsamples.
Particles in the 20/40, 40/60, 60/100 and -100 size fractions are
viewed under appropriate magnification, utilizing the same Zeiss Photo
microscope employed in the evaluation of airborne dust samples. Sub-
samples are prepared for viewing in the following manner: if the sample
consists of less than 300 particles, all particles are viewed. If the
sample consists of a larger number of particles, the quartering proce
dure mentioned previously is employed. Samples which contain only lint,
are scanned to determine whether or not trash particles are agglomerated
on the fibers. In addition, lint fibers from every sample are routinely
scanned for the same purpose. All subsamples are placed on a clean
glass slide and a No. 1-1/2 clean glass coverslip placed on top. The
13
subsamples are exposed to ref lected long-wave u l t rav io le t l i gh t and ob
servations made using a numerical aperture 0.20 Zeiss neofluar 6.3X
object ive. Part ic le counts are made by viewing f i f t y random f i e lds .
The number of BY 37-dyed part ic les re lat ive to the tota l number of
part ic les in a f i e l d is recorded, and this ra t io is mult ip l ied by the
f ract ion of a l l f ie lds containing BY 37-dyed par t ic les. This value is
then converted to a p e r - f i l t e r basis in order to obtain an estimate of
the re la t ive amount of labeled part iculate matter per sample.
CHAPTER IV
ENGINEERING ANALYSIS
The techniques of engineering analysis can provide valuable infor
mation in the definition of needed control technology for cotton textile
manufacturing. This engineering analysis is directed toward defining
the problem of fugitive cotton dust emissions in the early stages of
cotton textile manufacturing in terms of relative severity rather than
total dust emissions. This analysis also includes engineering studies
undertaken to determine the characteristics of each emission source.
Problem Definition
An estimation of the relative severity of cotton dust emissions in
the early stages of textile manufacturing can be made by determining
the percentage of labeled particles in airborne samples. Since these
estimates are based on the probability of finding labeled particles
in random samples, the nature of the data and results are relative
rather than absolute.
Engineering Studies
If labeled plant material is broken up by processing machinery,
then it should be possible to identify the sources of harmful emissions
by following the micronization of such material through opening, clean
ing, picking and carding into the respirable range. Toward this end,
the forces exerted on the cotton during each process step have been
evaluated qualitatively as to type and a relative force (F) calculated.
The classification of each force is based upon its primary application.
14
15
In this respect compression, impact and tensile forces correspond to
the respective applications of compressing, beating or pulling the cot
ton bat. Force calculations are based on the following equations:
w = fx (1)
f = ma/gc (2)
Ep = ngh/gc (3)
E, = 1/2 mv^/gc (4)
m = pV (5)
V = cor (6)
where a = acceleration (ft/s )
E, = kinetic work (ft Ib^)
E = potential work (ft Ib^)
f = force (Ib^)
g = acceleration due to gravity (ft/s ) 2
gc = conversion factor (32.2 Ib^ ft/lb^ s )
h = height (ft)
m = mass (lb„) m
r = radial arm (ft)
V = volume (ft )
V = linear velocity (ft/s) X = distance (ft) p = density (Ib^/^t^)
oj = angular veloci ty (rad/s)
The calculated force represents a re lat ive estimation of the work
done on the labeled part ic les in specif ic stages of manufacturing.
16
Apparently, much of the applied force is absorbed by the cotton bat
rather than the particles. Because of this, the force applied per area
of particle cannot be calculated. In addition, the masses and sizes of
the machinery have been used to estimate the forces exerted by the equip
ment. For these reasons, relative rather than quantitative estimates of
energy expenditure were used in the engineering analysis calculations.
Description of the Process
Opening, cleaning and picking consist of several steps to transform
a tightly formed bale of raw cotton, trash and other foreign material
into a lap or a rolled sheet of partially cleaned cotton ready for card
ing. These steps include such operations as blending, feeding, reduc
tion in particle size, waste remove!, material handling, evening, lap
formation and packaging.
The opening section of the Textile Research Center consists of four
feeders, as shown in Figure 1, each designed to receive the layers of
raw cotton by hand. The cotton is deposited on a slowly moving feed
apron (A) and carried to a faster moving inclined apron (B) which is
equipped with spikes to lift and carry the cotton up to the weigh pan
(C). As the cotton is carried up the inclined apron, the flow is regu
lated by the comb (D) which pulls the excess cotton back into the hopper
space. The cotton which is brushed off by the brush roller (E) into
the weigh pan is automatically weighed and dropped on a conveyor belt
(F). The forces applied in the feeders are predominantly tensile forces
used for opening and blending the large hand-fed masses of cotton.
17
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Before the cotton is fed into the Superior Cleaner, Figure 2, a
small compression force under a fifty pound roller (A) is applied.
This facilitates feeding into the Superior Cleaner. The Superior Cleaner
opens the cotton by a series of six horizontal beaters (B) arranged at
an angle of 60° upward. The entering cotton is picked up by the first
and lowest beater and progressively raised and beaten by each of the
succeeding beaters until it reaches the top. Each beater is fabricated
around a cylindrical drum fitted with metal studs mounted spirally
around the surface. Beneath each beater is a series of grid bars (C).
Opening is accomplished by the action of the beaters raking the cotton
over the grid bars. Impact forces are exerted on the cotton in this
process. Cleaning is accomplished as the heavier particles pass over
and fall through the grid bars into the collection bin (D).
From the Superior Cleaner, the cotton bat is pneumatically conveyed
to the impact cleaner. Figure 3. By using a fan to blow the cotton from
the Superior Cleaner to the impact cleaner, handling is reduced to a
minimum. At the inlet duct (A) to the impact cleaner, the cotton is col
lected on a revolving condenser screen (B). The air containing dust,
short fibers and trash passes through the perforated screen and into a
vacuum bag filter where the larger suspended particles are captured.
The cotton is removed from the screen by a doffer roll (C) and dropped
into the impact cleaner. The impact cleaner consists of seven spiked
beaters (D), similar to those in the Superior Cleaner, and seven grind
ers (E) covered with 0.5 inch long ceramic teeth. In the impact cleaner,
the cotton is further opened and cleaned by the action of the beaters
and grinders arranged at an angle of 60° upward. After being picked up
19
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21
by the first beater, the cotton is ground, beaten and raised by succeed
ing beaters and grinders until it reaches the top of the impact cleaner.
The action of beating and grinding the cotton is due primarily to im
pact forces. The heavier particles liberated during the process fall
out of the cotton bat, due to gravity, and into the collection bin (F)
in the bottom of the impact cleaner.
Following the impact cleaner, the cotton is dropped into the CMG'^
cleaner. Figure 4, where it is picked up on the licker-in cylinder (A).
The licker-in cylinder is covered with short metallic wire and acts by
tearing away tufts of cotton and carrying them to the worker cylinder
(B). The worker cylinder revolves at a higher rate than the licker-in
so that complete fiber transfer from licker-in to worker is affected
by a stripping action. The cotton is then combed onto the stripper
cylinder (C) and subsequently transfered back to the lick:r-in by the
same stripping action as before. The forces involved in these opera
tions are basically tensile in nature since the cleaning action is ac
complished by pulling fibers apart and allowing entrained particulate
matter to fall out. Once the cotton is transfered back to the licker-
in, impact forces are exerted in raking the cotton across a short sec
tion of grid bars (D) freeing the heavier material to fall out into
the collection bin (E). Lastly the cotton is brushed off the licker-in
by the brush roll (F) and discharged into a duct (G).
The cotton is now pneumatically conveyed to the feed hopper,
Figure 5, where it is collected on a revolving condenser screen (A).
Suspended particulate matter passes through the perforated screen and
into a second bag filter. The cotton is removed from the screen by a
22
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24
doffer roll (B) and dropped onto the feed apron (C). The primary func
tion of the feed hopper is to regulate the flow of cotton to the blade
beater. Cotton is lifted by a spiked inclined apron (D) and carried
up to the comb (E) which exerts tensile force to pull excess cotton back
into the feed hopper. The cotton passing over the top of the feed hop
per is brushed off by a brush roll (F) and onto a short horizontal
apron leading to the blade beater. This represents the first step in
picking, where the cotton is formed into an even, flat sheet to be roll
ed into a lap. In addition, final cleaning is performed.
At the blade beater. Figure 6, the cotton is gripped by a pair of
spring-loaded feed rollers (A) while the two-bladed beater (B) strikes
the cotton and drags it across the grid bars (C) to the double conden
ser screens (D) where the cotton is again formed into a flat sheet.
Trash particles and some short fibers fall out between the grid bars
into the waste as a result of impact forces exerted by the blade beater.
The fan (E) draws room air through the perforations in the top and bot
tom condenser screens and through the beater box (F). This air, con
taining entrained dust and cotton, passes down the dust flue and out of
the fan discharge (G) through the duct (H) and into the filter housing
(J). Then it passes through a perforated filter screen (K) and is re
circulated. This filter uses a mat of fibers as the filter medium.
The mat is continually stripped off and deposited into a waste recep
tacle as the filter screen revolves. The particulate matter removed
from the cotton on the double condenser screens, which is too large to
remain suspended in the air stream falls out and is collected under the
double condenser screens.
25
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26
The cotton passes from the blade beater to the Kirshner beater.
Figure 7. Here the cotton is deposited into a blending reserve (A).
The purpose of the blending reserve is to maintain a uniform flow of
cotton to the Kirshner beater (B) where the final picker cleaning takes
place. The Kirshner beater is a three-leg steel beater fitted with
small spikes on the base of each leg. As the cotton is fed to and held
by the evener roller pedal (C), the Kirshner beater strikes the cotton
downward and across the grid bars (D) dislodging much of the remaining
trash which falls out through the grid bars. The forces exerted by the
Kirshner beater in striking the cotton are predominantly impact in
nature. The cotton is thrown up onto the double condenser screens (E)
and reformed into the final sheet. As in the blade beater section,
the Kirshner section fan (F) draws room air through the double conden
ser screens, picking up small trash particles and short fibers. The
dirty air stream is routed through the duct (G) to a perforated filter
screen (H). The cleaned air is then recirculated. Larger trash parti
cles fall out of the air stream and into the waste under the double con
denser screens. The final compression of the loose sheet of cotton into
the picker lap occurs in the calender roll section. Figure 8. The sheet
of cotton is subjected to compression forces to bind the bunches of
cotton together so that they remain in sheet form for rolling. This
is accomplished by a stack of four calender rolls (A) one above the
other. Next, the lap is fed to the lap arbor (B) where it is rolled
into the picker lap for carding.
The process of cotton spinning actually begins in carding. Fig
ure 9. The purpose of carding is to separate the fibers into their
27
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30
individual elements and align them in parallel fashion. During carding,
most of the remaining dust and foreign matter as well as many short
fibers are removed. The picker lap (A) is fed beneath a feed roll (B),
resting against the feed plate (C), which regulates the flow of cotton
being worked on by the licker-in (D). The licker-in is a hollow cylin
der covered with metallic wire. It acts to open the cotton lap by tear
ing away tufts of fiber (tensile forces exerted) and carrying them to
the main cylinder (E). Mote knives (F) are set below the licker-in and
serve to catch and pull out foreign matter. The main cylinder, covered
with fine wire clothing, revolves faster than the licker-in, permitting
complete fiber transfer through a stripping action involving tensile
forces. The cotton fibers are carried up to the flats (G) where card
ing occurs. The flats consist of approximately one hundred and ten
narrow flat surfaces covered with fine wire clothing to match the main
cylinder. The flats move slowly in the same direction as the main
cylinder. The wire points on the flats are inclined backwards or op
posite to the direction of the wire points on the main cylinder. The
action between the two sets of points permits the fine separation of
fibers through the application of tensile forces. The transfer of
cotton fiber from the main cylinder to the slower doffer roll (H) is
also due to carding action. Following this, the thin film of cotton is
stripped from the doffer roll as a web by the action of the doffer comb
(J) and the wide sheet of card web is then drawn and gathered into a
round sliver by the action of the two doffer calender rolls (K). Last
ly, the sliver is fed to the coiler (L).
CHAPTER V
RESULTS AND DISCUSSION
The flow scheme covering the early stages of textile manufacturing
in the Textile Research Center is shown in Figure 10. All sampling
points are indicated.
Tables 1 and 2 show the relative forces exerted on the cotton at
specific locations in opening and cleaning and picking, respectively.
It also shows the corresponding percentage of labeled particles by size
class found in samples at these and other various locations.
Referring to Table 1, the small tensile and compression forces ex
erted in the feeders and under the roller preceding the superior clean
er may be neglected. As a result of the impact forces accompanying the
p
Superior, impact and CMG cleaners, labeled material in the lint is dis
lodged and falls into the waste streams. As the impact force increases
more than two-fold from the Superior cleaner to the impact cleaner,
the percentage of labeled particles tends to decrease in the 14/20 and
20/40 size ranges and increase in the 40/60 and -100 size ranges. This
is apparently the result of mechanical disintegration or micronization
brought about by impact forces. Consequently, the percentage of labeled
particles in smaller size ranges is expected to increase as the larger
particles disintegrate. It is observed that the percentage of labeled
particles in the large and middle size ranges in the waste sample from
the CMG^ cleaner remains essentially constant while the percentage of
labeled particles in the smaller size ranges decreases. This indicates p
that the significant tensile force exerted in the CMG cleaner does not
31
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34
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result in as great a disintegration of particulate matter as does the
impact force. Comparing lint before and after cleaning, the percentage
of labeled particles in the large size ranges has decreased due to the
cleaning operations noted with a corresponding increase in percentage
of labeled particles in the 14/20 size range. This is most likely also
due to micronization. Referring to Tables 1 and 2, it is evident that
a further decrease in the percentage of labeled particles in the lint
occurs as a result of filtering action at the second condenser.
It is observed (Table 2) that the tensile force exerted in the
feed hopper is negligible. Referring to Table 2, as a result of the
impact force accompanying the blade beater, labeled material is trans
fered from the lint to the waste stream. Compared to the preceding D
waste stream at the CMG cleaner (Table 1), the blade beater waste
stream shows that the percentage of labeled particles decreases in the
largest (+10) size fraction with a corresponding increase in all but
one of the smaller size ranges. This further indicates that the impact
force creates smaller particles by disintegrating the larger ones.
Additional evidence is found by following labeled material into the
respirable range (Table 3). The percentage of labeled particles in
the respirable sample collected nearest the blade beater (VE2) is
twice as large as in the respirable sample collected next to the feed
hopper (VEl). A significant decrease was observed in the percentage
of labeled particles in the larger and smaller size ranges in the
waste stream from the Kirshner beater. A three-fold increase was also
noted in the percentage of labeled particles in the respirable dust
sample collected at the Kirshner beater (VE3 vs. VE2, Table 3). This
36
Table 3
Percentage of Labeled Particles in Respirable Airborne Dust
Dust Percentage Sampler Location Labled Particles
VEl East of feed hopper 0.27
VE2 East of blade beater and blade beater condenser
VE5 In front of doffer and between cards
VE6 In front of doffer and next to coiler
0.54
VE3 East of Kirshner beater and i ^2 Kirshner beater condenser
VE4 East of calender rolls 0.80
0.97
0.37
37
corresponds to a three-fold increase in impact forces (Table 2) from
the blade beater to the Kirshner beater, further indicating a relation
between impact force and harmful dust emissions. Since undyed leaf
like material behaves like BY 37-dyed leaf (19), these results indicate
that the percentage of all light, friable particles, such as leaf and
bract, are micronized into the respirable range in direct proportion
to the magnitude of the impact forces exerted.
Comparing the lint samples before and after the blade beater, it
is found that the percentage of labeled particles has increased in both
size ranges containing labeled particles. This apparent de novo gen-
eration may be explained by considering the disintegration of the parti
cles. Due to the greater surface area of the larger particles, one
large particle can be broken up into numerous smaller particles. Thus
one large particle in the lint sample before the blade beater could have
been missed in counting and have been broken up into the high percentage
of labeled particles after the blade beater. This is also the case
with the sample of lint at the calender rolls and the picker lap, which
also indicates de novo generation of smaller particles. It should be
noted that in both cases only one labeled particle was found in each
sample. The reason larger particles may have eluded counting is un
doubtedly due to sampling error. In any case, the results indicate
that friable particles are broken up and that the percentage of labeled
particles increases in the lint as it follows the flow path through
picking (Table 2). Referring to Table 3, it can be seen that the per
centage of labeled particles in the respirable range decreased at the
calender rolls (VE 4). This is expected since compressive forces are
38
applied which act to entangle the fibers and trap the particulate
matter.
Finally the data in Table 4 indicate that the percentage of label
ed particles in the total dust samples collected by the stationary high
volume samplers (SHV) increases down the flow path. It should be noted
that the roving high volume samplers (RHV) were placed on movable mounts
in order to assist in locating the dust emission points in opening,
cleaning and picking rather than accurately measuring those emission
levels. The equipment blower filter samples (EBFl and EBF2) represent
a better measure of the emissions as the cotton flows through the open
ing and cleaning sections. The stationary high volume results in
Table 5 also indicate, as do the results in Table 4, that friable,
leaf-like dust emissions increase as lint proceeds from opening through
picking.
Referring to Table 5, it is observed that the percentage of labeled
particles steadily decreases in the waste and lint as the lap moves
from the licker-in to the sliver end of the cards with the great major
ity of the waste falling out under the licker-in. In addition, the
data in Table 4 show that the percentage of labeled partioles, and thus
the percentage of leaf-like material, decreases in the total dust samples
as the picker lap moves from the licker-in toward the sliver end of
the cards. Apparently, this is the result of leaf (and by inference,
bract) disintegration not being as great in carding as in opening,
cleaning and picking due to the lack of impact forces. More trash, in
cluding labeled particles, is removed at the inlet to the card and less
emitted as airborne particulate matter. As evidence. Table 5 shows
39
Table 4
Percentage of Labeled Particles in Total Airborne Dust
Dust Sampler
SHVl
SHV2
SHV3
RHVl
RHV2
RHV 3
RHV4
RHV5
RHV6
RHV7
RHV8
RHV9
RHVIO
RHVll
EBF2
EBFl
Location
North of feeders
East of superior cleaner
Southeast of calender rolls
East of feeders
Underneath superior cleaner
Northwest of impact cleaner
North of CMG* cleaner
East of feed hopper and superior cleaner
East of blade beater and feed hopper
East of blade beater condenser
Behind and to the side of licker-in
Beside main cylinder
In front and to the side of
During clean-up
doffer
South of impact and CMG cleaner
East of feed hopper
Percentage Labeled Particles
0.44
1.78
3.07
1.44
0.28
0.56
1.06
0.87
0.0
0.0
1.70
0.70
0.33
3.33
0.56
0.23
40
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41
that the percentage of labeled particles in the waste sample collected
at the flats and main cylinder is much less than that in the waste
sample collected at the licker-in. The trash, including labeled parti
cles, is removed from the lint primarily on the inlet side of the card.
Thus, there is less opportunity for it to be disintegrated by the flats
and converted into airborne particles.
R
The Pneumafil samples (Table 5) represent a good measure of poten
tial airborne particulate matter captured at the card. Because most
particulate matter is removed at the card inlet, the percentage of
labeled particles (and thus, the percentage of light, friable particles)
is much less in the sample of sliver (Table 5) than in the sample of
picker lap (Table 2). The percentage of labeled particles is less in
the high volume sample collected at the doffer (RHVIO, Table 4) than in
the roving high volume sample collected at the licker-in (RHV8, Table 4)
It appears that the cards clean the picker lap without much of the ac
companying emission problem present in opening, cleaning and picking.
The vertical elutriator results at the end of carding (Table 3) differ
because one was situated between the two cards in use (VE5) while the
other (VE6) was opposite the end of card 4. These results also indi
cate that the percentage of labeled particles (and presumably all light,
friable particles) micronized into the respirable range is less in
carding than in picking.
Particles emitting a bright yellow fluorescence were found on all
vertical elutriator samples. This demonstrates the feasibility of
tracing the micronization of gross components of cotton trash into the
range of particle capture by the vertical elutriator (VE) cotton dust
sampler.
CHAPTER VI
CONCLUSIONS AND RECOMMENDATIONS
The ability to follow the micronization of fluorescently labeled
cotton leaf into fine trash and airborne particulate matter in the early
stages of cotton textile manufacturing, opening through carding, has
been demonstrated. Labeled particulate matter was found in all elutri
ated dust samples, clearly demonstrating the feasibility of easily and
accurately following labeled botanical constituents through successively
finer micronizations into the respirable range. Based on the engineer
ing analysis, it is concluded that the relative severity of fugitive
cotton dust emissions and the forces exerted on the cotton during the
early stages of cotton textile manufacturing are related.
This work should be repeated, starting with ginning, employing
bract as the labeled material in sufficient quantity (1 or 2 weight
percent) to allow tracing through weaving. To simplify the identifica
tion of de novo particle generation, a narrow size range of large parti
cles (2 mm - 12.5 mm) should be used. A single sampling procedure which
would yield a permanent record, applicable to the entire size range
of macro-samples, should be developed. A total material balance should
be made in all future work so that the amount of bract micronized in
any portion of cotton ginning or textile manufacturing can be quanti
tatively determined. The results from the present study should be used
to define the direction for process machinery improvement aimed at de
creasing dust emissions and improving the efficiency of existing occupa
tional dust control technology in textile mills.
42
REFERENCES
1. Bethea, R. M.: Air Pollution Control Technology, pp. 61-94. Van Nostrand Reinhold Company, New York, NY (1978).
2. Bethea, R. M., Rowlett, C. D., and Morey, P. R.: "Evaluation of a Fluorescent Dust Tracer Technique in Cotton Ginning." Am. Ind. Hyg. Assoc. J., 39.: 998-1008 (1978).
3. Bouhoys, A.: "Byssinosis in Textile Workers." Trans. N.Y. Acad. Sci., 28: 480 (1966).
4. Bouhoys, A. and Nicholls P. J.: "The Effect of Cotton Dust on Respiratory Mechanics in Man and in Guinea Pigs," pp. 75-85 in Inhaled Particles and Vapors II, Davies, C. N. (ed.) Pergamon Press, New York (1967).
5. Cocke, J. B., and Hatcher, J.D.: "Levels of Cotton Dust in Experimental Card Room As Influenced By Production and Processing Parameters," pp. 395-415 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygie-nists, Cincinnati, OH (1975).
6. Corley, T. E.: "Basic Factors Affecting Performance of Mechanical Cotton Pickers." Trans. Am. Soc. Agri. Eng., 9.: 326-332 (1966).
7. Fischer, J. J., Battigelli, M. C , and Foarde, K. K.: "Microbial Flora of Weeds Commonly Found in Cotton," pp. 110-113 in Proceedings of Beltwide Cotton Production - Mechanization Conference Special Session on Cotton Dust, Dallas, TX (1978).
8. Gamble, J. F., Fischer, J. J. and Battigelli, M. C : "Alternative Methods of Exposure in Provacative Tests in Byssinosis: Preliminary Observations," pp. 110-130 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
9. Graham, C. 0. Jr., Kingsberry, E. C , and Rusca, R. A.: "Factors Influencing Dust Levels During Cotton Processing." iransactions of the National Conference on Cotton Dust and Health, p. 45, School of Public Health, Charlotte, NC (1971).
10. Hatcher, J. D.: "Physical Characteristics of Cotton Dust Generated in Different Processing Areas of a Cotton Mill," pp. 271-283 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
43
44
11. Hocut, R. H.: "Engineering Controls For Cotton Dust in Yarn Manufacturing Plants," pp. 416-425 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
12. Imbus, H. R.: "Experience With Medical Surveillance Programs," pp. 17-26 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
13. Key, M. M.: "Criteria Document: Recommendations For an Occupational Exposure Standard For Cotton Dust," U.S. Department of Health, Education, and Welfare, PHS, CDC, NIOSH, HEW publication No. 75-118 (1974).
14. McKerrow, C. B., and Schilling, R. S. F.: "A Pilot Enquiry Into Byssinosis in Two Cotton Mills in the U.S." J. Am. Med. Assoc, 177: 850-853 (1961).
15. Merchant, J. A., O'Fallon, W. M., Lumsden, J. C , and Copeland, K. T.: "Determinants of Respiratory Disease Among Cotton Textile Workers," pp. 27-39 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
16. Morey, P. R.: "Botanical Trash Analysis of Raw Materials Used in the Cotton Garnetting Industry." Am. Ind. Hyg. Assoc. J., 4£: 264-269 (1979).
17. Morey, P. R., Bethea, R. M., Kirk, I. W., and Wakelyn, P. J.: "Identification of the Botanical Origin of Visible Wastes From the Shirley Analyzer," pp. 237-265 in Cotton Lust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
18. Morey, P. R., Bethea, R. M., Wakelyn, P. J., Kirk, I. W. and Kopetzky, M. T.: "Botanical Trash Present in Cotton Before and After Saw-Type Lint Cleaning." Am. Ind. Hyg. Assoc. J., 37_: 321-238 (1976).
19. Morey, P. R., and Raymer, P. L.: "Fragmentation of Cotton Bract and a Technique for Detecting Bract in Cotton Dust." Agronomy J., 70: 644-648 (1978).
20. Morey, P. R., Sasser, P. E., Bethea, R. M., and Hersh, S. P.: "Use of Dyed Leaf in Studies on The Origin of Cotton Dust," pp. 97-104 in Proceedings of Beltwide Cotton Production -Mechanization Conference Special Session on Cotton Dust, Dallas, TX (1978).
45
21. Morey, P. R., Sasser, P. E., Bethea, R. M., and Kopetzky, M. T.: "Variation in Trash Composition in Raw Cottons." Am. Ind. Hyg. Assoc. J., ^: 407-412 (1976).
22. Morey, P. R., Wanjura, D. F., and Baker, R. V.: "Comparative Anatomical and Ginning Characteristics of Two Upland Cotton Cultivators." Agronomy J., 66 : 820-822 (1974).
23. Parnell, C. B. Jr.: "Mass Concentrations and Particle Size Distribution of Dust in Cotton and Synthetic Fibers," Paper presented at the winter meeting of the American Society of Agricultural Engineers, Chicago, IL (1978).
24. Rylander, R. and Snella, M.: "Bacterial Contamination of Cotton As a Factor Determining Its Pulmonary Toxicity," pp. 101-109 in Cotton Dust, Proceedings of a Topical Symposium. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
25. Sinclair, S.: "The Cotton Dust Controversy," in Job Safety and Health. U.S. Department of Labor, Occupational Safety and Health Administration, ±1 4-12 (1976).
26. Sinclair, S.: "Views at Odds," in Job Safety and Health. U.S. Department of Labor, Occupational Safety and Health Administration, i: 13-17 (1976).
27. Taylor, W. E. and Sasser, P. E.: "Steaming Lint Cotton For Control of Byssinosis in Cotton Textile Mills," Paper presented at the winter meeting of the American Society of Agricultural Engineers, Chicago, IL (1976).
28. U.S. Department of Labor, Occupational Safety and Health Administration: Occupational Exposure to Cotton Dust, Federal Register, Vol. 43, No. 122, pp. 27350-27463, June (1978).
29. Vaughn, E. A. and Rhodes, J. A.: "The Effects of Fiber Properties and Preparation on Trash Removal and Properties of Open-End Cotton Yarns." Journal of Engineering for Industry, February: 71-76 (1977).
30. Wesley, R. A., Cocke, J. B., and McCaskill, 0. L.: "Effects of Condenser Drum Covering at Cotton Gins on Card Room Dust and Quality of Yarn Produced by Open-End Spinning," Paper presented at winter meeting of the American Society of Agricultural Engineers, Chicago, IL (1978).
31. Wessling, W. H.: "Genetic Plant Characteristics and Cultural Practices That Affect Trash Content in Cotton Fiber," pp. 199-200 in Cotton Dust, Proceedings of a Topical Symposium._ American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1975).
APPENDIX
46
CALCULATIONS
Feeders and Feed Hoppers
Fy = E. = 1/2 mvVgc (tensi le force)
where: v = 1.2 f t / s -> v^ = 1.44 f t ^ / s ^
gc = 32.2 Ib^ f t / l b ^ s^
m = pV
where: p = 34 lb /ft m
(wood)
V = (length)(width)(depth)
V = (12 f t ) ( 4 f t ) (0 .05 f t )
V = 2.4 f t ^
34 lb m = m
2.4 ft^ = 81.6 lb.
E, =
f t "
(0.5) 81.6 lb
m
m 1.44 f t ' I f ^ s'
32.2 lb f t m
F- = 1.8 f t Ib^ = 2 f t Ib^
Roller
F = Ep = mgh/gc (compression force)
where: m = 50 lb m
g = 32.2 f t / s '
h = 0.0208 f t
47
48
gc = 32.2 Ib^ f t / l b ^ s'
50 lb. E =
P m
32.2 f t 0.0208 f t
F =1 .04 f t l b . = 1 f t l b . c t f
Ib^ s'
32.2 Ib^ f t m
Superior Cleaner
Fj = E^ = (1/2 mvVgc)jjg^^g^ * 6 beaters (impact force)
where: gc = 32.2 Ib^ f t / l b ^ s
m = pV
p = 490.75 I b ^ / f t ^
V = V 1 + V ., ^ annulus spikes
(carbon steel)
V 1 = Tr[(outer radius)^ - (inner radius) Jlength annulus
circumference _ 2.67 f t where: outside radius =
and;
27T 2TT
outside radius = 0.43 ft
inside radius = 0.43 ft - 0.02 ft = 0.41 ft
length = 2.55 ft
V , = Tr[(0.43 ft)^ - 6.41 ft)^]2.55 ft annulus
annulus
spikes
V -I spikes
= 0.14 ft^
+o^ spikes = [(length)(width)(depth)]per spike *26 ^^^;^^^p[u<
= [(0.33 ft)(0.03 ft)(0.08 ft)]*26
and: spikes = 0.02 ft
therefore: V = 0.14 f t ^ + .02 f t ^
V = 0.16 ft"^
49
and: 490.75 lb m = m
ft^
0.16 fr
m = 78.52 lb m
V = 0) • r
where: oo = 360 rpm (0.1047) = 37.69 rad
and
0.43 f t
rad r
V = 37.69 0.43 f t
E,. = (0.5) 78.52 lb
m
= 16.21 f t / s
.2 262.76 f t ' Ib^ s'
32.2 lb „ f t m
Fj = 1922.23 f t Ib^ = 1900 f t Ib^
Impact Cleaner
h = h ^ (1/2 mv2gc)^g^^g^5 + (1/2 mv /9c)g,^„^^^^ (impact force)
where* m. ^ = (135 lb ). ^ *7 beaters wrier c. '"beaters ^ m'beater
m. ^ = 945 Ib^ beaters m
m gr i = (300 lb ) . J *7 grinders nders ^ "'m-'grinders ^
m . . = 2100 Ib^ grinders m
and: V = oj • r
where: cu^^g ters ^ ^^^ ''P'" (0.1047) = 33.92 rad
50
'•beaters = °- ^^ ^^
(jJ grinders = ^10 rpm (.1047) = 2 1 . 9 9 ^
V i n d e r s = °-^^ ^^
rad. ^beaters^ (33.92 i f )(0.38 f t )
V a t e r s = ^2.89 f t / s
rad. V i n d e r s = (21.99 ^ ) (0.46 f t )
^nv^-in/Hnv^c = ^0.^2 f t / S
grinders
E.. = (0.5) 945 Ibj^ 166.15 f t ^ Ib^ s'
(0.5) 2100 lb m
102.41 f t2
32.2 Ib^ f t m p
Ib^ s"
32.2 Ib^ f t m
Fj = 5777.53 ft Ib^ = 5800 ft Ib^
CMG^ Cleaner
T = kT = (/2 '''^^^'hic^er-in " ' ^ mv^/gc)^^^^^,
2 ) + (1/2 mv /gc^str ipper
Fj = E J = (1/2 mv / gc ) , i , | , e , . i n
(tensi le force)
(impact force)
where: m^. , • = 595 l b „ wiicic. " ' iTcker-in m
m , = 170 l b „ worker m
m ^ . = 170 Ib^ str ipper m
and: V = (jj • r
where: w l i c ke r - i n ^ ^^^ ^P" (0.1047) = 44.81 rad
^worker = ^^ ' P' (0.1047) = 57.59 ^ ^
'^stripper " "'^^ ''P" (0.1047) = 10.47 rad
' l i cke r - in " °-^^ ^^
"worker = ^'^^ ^^
S t r i p p e r = ^'^^ ^^
V = 44.81 rad l i c ke r - i n s ^-^^-^= 30.02 f t / s
V = ''Q'47 rad str ipper s
0.42 f t = 4.40 f t / s
595 l b „ E^^ = (0.5) ^
901.2 f t ' Ib^ s'
170 lb + (0.5) 21
585.16 f t '
32.2 lb „ f t m
Ib^ s'
32.2 lb „ f t m
170 Ib^ + (0.5) ^
19.36 f t ' Ib^ s'
32.2 lb f t m
F-j. = 9922.09 ft Ib^ = 9900 ft Ib^
and Ej j = (0.5) 595 lb
m 901.2 ft' Ib^ s'
32.2 lb ft m
Fj = 8326.30 ft Ib^ = 8300 ft Ib^
Blade Beater
Fj = E = 1/2 mvVgc (impact force)
51
where: V = w • r
CO = 940 rpm (0.1047) = 98.42 —
r = 0.67 ft
52
and V = 98.42 rad 0.67 ft = 65.94 ft/s
m = pV
where: p = 490.75 lb /fV m
and:
(carbon steel)
shaft " rings " ^studs " ^bars
^shaft " "•(shaft radius) length
shaft radius = ci'-cumference ^ 0^77_ft , 0 , 2 f t
length = 3.54 f t
and: ^shaft " "^(O-l^ f t ) ^ 3.54 f t
^shaft = 0-16 f r
V . = V . *5 rings rings r ing ^
2 2 V . = 7r[(outer radius) - (inner radius) ] length r i n g •• / j a
. . . ,. circumference 1.08 f t _ ry i-i ^^. outside radius = 2 —2T\
inner radius = shaft radius = 0.12 f t
and:
length = 0.17 f t
V . = 7r[(0.17 f t ) ^ - (0.12 f t )^ ]0 .17 f t r ing ^
Ving = °-°°8 '^'
53
Vings = °-°4 f t '
^studs = ^stud *10 '^^"^
stud ^ using top using bottom ^^ e l l i p t i c a l ares e l l i p t i c a l ares
^ s i n g top = ^ " ^^op * ^^"9^^ e l l i p t i c a l area
and: Area.^„ = TT a • b top
where: a-j. = 0.08 f t
b j = 0.05 f t
Area^Q = 7T(0.08 f t ) (0.05 f t ) = 0.01 f t ^
length = 0.47 f t
V . ^ = (0.01 f t^) (0.47 f t ) = 0.005 f t ^ using top e l l i p t i c a l area
V . . 4. = Area. ^^..^„ * length using bottom bottom e l l i p t i c a l area
and: Area. .^ = TT a • b dnu. ""=°bottom
where: ag = 0.09 f t
bo = 0.05 f t D
Area, , , = Tr(0.09 f t ) (0.05 f t ) = 0.014 f t ^ bottom
length = 0.47 f t
54
V . , ^ = (0.014 ft^)(0.47 ft) = 0.007 ft^ using bottom ^ e l l i p t i c a l area
and: V ^ • = (0.005 f t ^ + 0.007 f t ^ ) / 2 = 0.006 f t ^ stud ^
^"^^ ^3^^^^ = 0.006 f t ^ * 10
^ t u d s = 0-0^ ' ' '
Vbars = bar *2 bars
^bar = ^"^^of trapezoidal face * ^^"^th
and: Area^^ trapezoidal face = H " ^ ^
where: a = 0.14 ft
b = 0.17 ft
h = 0.04 ft
Area . = (Q-^^ f t ^ 0.17 ft^Q p^ ^^ '^^^^of trapezoidal face ' 2
Area . • ^ -, ^ = 0-006 f t ^ ^•^^^of trapezoidal face
length = 3.42 f t
V. = (0.006 f t^ ) (3 .42 f t ) = 0.02 f t ^ bar ^
V = 0.16 f t ^ + 0.04 f t ^ + 0.06 f t ^ + 0.04 f t
3
m = (490.75 l b ^ / f t ^ ) ( 0 .3 f t ^ )
so:
and: V = 0.3 f t
55
• • •
m = 147.23 Ib^ m
147.23 l b „
L^ - [0.:,)
4348.08 f t
s2
Fj = 9940.33 f t Ib^ = 9900 f t Ib^
Kirshner Beater
2 2 Ib^ s"
32.2 Ib^ f t m
Fj = E^ = 1/2 mv'^/gc (impact force)
where: V = 03 • r
03 = 880 rpm (0.1047) = 92.14 rad
and
r = 0.63 ft
V = 92.14 rad Q-^^ ^ = 58.05 ft/s
m = m _ _• + m. wood "'steel
m = P V wood ^wood wood
whe^^- Pwood = " ^^m^^^^
^wood " ^wood bar wood bars
^wood bar "- "'^of trapezoidal face * ^^"^th
= (lL±_b)h ^^^^of trapezoidal face ^ 2
where: a = 0.46 ft
b = 0.50 ft
h = 0.07 ft
56
Area . , ., , , = (0.46 ft H- O.50 ft.^ .^ .. of trapezoidal face ^ 2^ jU.UZ ft
Area of trapezoidal face " ^'^^^ ^^'
length = 3.42 f t
and: ^wood bar = (0-034 f t^) (3.42 f t )
^wood bar " 0 . 1 2 ft^
^wood = (0-12 f t ^ ) * 3
^wood = 0-36 ^ '
and: m . = 34 —? wood ,^3 ft^
0.36 f t '
m,, . = 12.24 lb wood m
m steel ^steel steel
"here: p^^^^, = 490.75 I b ^ / f f
Steel shaft rings bars studs
where
^shaft ~ '^(^'^^^^ radius) * length
ch.^+ v1=/ -;Mc - circumference _ 0.65 ft shaft radius - TT- TT-
shaft radius = 0.10 ft
length = 3.58 ft
and: V . . = 7T(0.10 ft)'^(3.58 ft) snatt
^shaft = 0 - " '"•'
57
. V ings = V i n g *^ "^"^s
2 9
^ring ^ "^[(outer radius) - (inner radius) ] length
where: outer radius = shaft radius + 0.073 f t
outer radius = 0.10 f t + 0.073 f t
outer radius = 0.173 f t
inner radius = shaft radius = 0.10 f t
length = 0.25 f t
^r ing " ^[(0-173 f t ) ^ - (0.10 f t )2]0.25 f t
^ i n g = 0-016 f t ^
and: V^.^^^ = (0.016 f t ^ ) *4 = 0.064 f t ^
^bars = bar ^ t)ars
where: V ^ ^ = Area^^ trapezoidal face * ^"^th
^"^^of trapezoidal face " (~-2~)'^
where: a = 0.46 ft
b = 0.38 ft
h = 0.19 ft
_ ,0.46 ft + 0.38 ft^n TO f^ Area ,- - ^ -^ ^ - ( o )0.19 ft
of trapezoidal face ^ 2 ' Area ^ . -^ ^ ^ = 0.08 ft^ of trapezoidal face
length = 3.42 ft
58
" - V. ^ = (0.08 ft2)(3.42 ft) bar
Vbar - 0-27 ft^
^bars = (0-27 ^ i ) * 3
^bars =0-81 ft^
^studs = V^tud *12 studs
where: V^^^^ = Area^^ trapezoidal face * l«"9th
' '" of trapezoidal face " ( ^ — ) h
where: a = 0.10 ft
b = 0.17 ft
h = 0.21 ft
Area , , ., , , - (0-10 ft ^ 0.17 ft^^^^ of trapezoidal face ^ 2 '
Area . ^ - i ^ = 0.028 ft^ of trapezoidal face
length = 0.25 ft
and: V^^^^ = (0.028 ft2)(0.25 ft)
V ^ . = 0.007 ft^ stud
V , . = (0.007 ft-^)*12 studs
V ^ . = 0.084 ft" studs
and: V^^^^^ = 0.11 ft^ + 0.064 ft^ + 0.81 ft^ + 0.084 ft^
and:
^steel =1.068 f t '
490.75 lb m m
steel f t '
1.068 f t '
m^,^^^ = 524.12 Ib^
so: m = 12.24 lb + 524.12 Ib^ m m
m = 536.36 lb m
E = (0.5) 536.36 lb
m 3369.80 f r Ib^ s'
32.2 Ib^ f t m
Fj = 28065.62 f t Ib^ = 28100 f t Ib^
Calender Rolls
^c = " k (compression force)
W = fx
where: f = ma/gc
m = m. + m, weights bars
m. . u.. = m ^.^UH- *2 weights "weights weight
m . u^ = 58 lb„ weight m
so: m .nnh+c = (58 lb^)*2 = 116 lb weights ^ m m
'"bars (^steel^^bars
59
where: p^^^^^ = 490.75 Ib^/ft'
Vu = V. *2 bars bars bar
60
^h;,y = Tr(average radius of bar) * length bar
average radius of bar = .125 f t
length = 1.75 f t
^bar = " " ( - l ^ ^ f t )2*1.75 f t )
^bar = 0-086 f t '
^bars = 0.086 f t ^ * 2
and
V. = 0.172 f t ' bars
490.75 lb m
m bars ft^
0.172 f t '
m = 84.41 Ib^ bars m
so m = 116 Ibj^ + 84.41 Ib^
m = 200.41 lb m
and: a = 32.2 f t / s '
gc = 32.2 lb f t / l b ^ s
so:
200.41 lb f = m
32.2 f t Ib^ s'
32.2 Ib^ f t
f = 200.41 lb.
and: X = 6.33 f t
61
so: W = (2-0.41 lb^)(6.33 f t )
W = 1268.60 f t Ib^
'^ -' i^-i ^^1 where i = compression steps
Ek = 1/2 m^V ' /gc
m.| = pV * 2
where: p = 490.75 Ib^/ f t^
V = TT(radius of r o l l ) * length
radius of r o l l = 0.21 f t
so:
and:
length = 3.33 f t
V = Tr(0.21 f t )2(3.33 f t )
V = 0.46 f t ^
lb m. = 490.75 — ^
' f f ^
0.46 f t ' (2)
m = 451.49 Ib^
so
V = 0.23 f t / s
451.49 lb
ki = (°-^'-m
0.053 f t Ib^ s
32.2 Ibj^ f t
E l , = 0.37 f t Ib^ kl
E 2 = 1/2 m2V2 /gc
m2 = pV * 3
62
where p = 490.75 Ibj /ft'
V = 0.46 fV
so:
so
lb_ m / i o n "7cr m.p - 490. /b -
^ fV
0.46 f f^ / I N
m^ = 677.24 Ib^
V2 = 0.23 f t / s
677.24 Ib^ r (n r\ ^
k2 ~ ( - ^
0.053 f t ^
s'
2 Ib^ s^
32.2 l b „ f t m
E 2 = 0.56 ft Ib^
hs - 1/2 V 3 /9C
m3 = pV * 4
where: p = 490.75 lb /ft m'
so
so:
V = 0.46 f t "
490.75 Ib^
'•'3 - f t 3
^3 = 903 Ib^
v , = 0.23 f t / s
0.46 ft'^ (4)
903 lb
Ek3 = (°-5) m
0.053 ft' Ib^ s
32.2 Ib^ ft
E,, = 0.75 ft lb,
E. = 0.37 ft lb, + 0.56 ft lb, + 0.74 ft lb,
E, = 1.67 f t l b .
F = 1268.60 f t l b , + 1.67 f t l b .
63
F = 1270.3 f t l b , = 1300 f t l b .
L icker- in
F = E, = 1/2 mvVsc (tensi le force)
wher •e:
and:
where:
so:
so.
• • •
Flat
^T =
s and
m = 175 lb m
V = 03 • r
03 = 730 rpm (0.1047) - 76.43 ^^^
r = 0.42 f t
\! - If, Ari ^^^ V / D . H-O •
S
V = 32.1 f t / s
0.42 f t
\
175 Ib^
k ~ ^ '
1030.41 ft"^
2 s
E| = 2800.03 f t l b .
2800.03 f t l b , = 2800 f t l b .
Main Cylinder
l b , s^
32.2 l b „ f t m
' T ^k f l a t s "*" k main cylinder (tensi le force)
64
where V = 0.005 f t / s
m = m,:, . * 110 f l a t s TI a t
and; " 4^1^+ - 7.5 l b „ f l a t m
so: m = 7.5 lb * 110 m
so:
m = 825 lb m
^k f l a t s = (0.5) 825 lb
m 0.000025 f t ' l b , s'
32.2 lb f t m
k flats = °-°0°3 f t Ibf
^k main cyl inder = 1/2 mv /gc
where m = 1800 l b m
where:
V = 03 • r
03 = 170 rpm (0.1047) = 17.8 rad
so:
r = 2.08 f t
V = 17.8 rad 2.08 f t
1800 lb m
V = 37.02 f t / s
E . T ^ = (0 .5 ) • k main cylinder
F n. ^ = 38305.35 f t l b . " k main cylinder T
1370.48 ft' lb, s'
32.2 lb ft m
F.. = 0.0003 ft lb, + 38305.34 ft lb.
F- = 38305.34 ft lb, = 38300 ft lb.
Doffer and Main Cylinder
F = E + E T k main cyl inder k doffer
^k main cyl inder = 38305.34 f t l b ,
^k doffer = 1/2 "iv^/gc
(tensi le force)
65
where: m = 900 lb m
V = 03 • r
where: 03 = 8.57 rpm (0.1047) = 0.9 —
r = 1.125 f t
so: V = 0.9 rad 1.125 f t
V = 1.01 f t / s
^°^ ^k doffer = (0.5) 900 lb.
m 1.02 f t ' l b , s'
32.2 Ib^ f t m
^k doffer = 1^-25 ^t l b .
F = 38305.34 f t l b , + 14.25 f t l b .
F = 38319.59 f t l b , = 38300 f t l b .
Sl iver
' T " 2 * ^k doffer calender r o l l ( tensi le force)
E . ^ n = V2 mv' /gc ' k doffer calender r o l l
66
where m = pV
so:
and:
P = 490.75 lb / f t ' m
V = Tr(radius of doffer calender r o l l ) ^ * length
radius of doffer calender r o l l = 0.125 f t
length = 0.42 f t
V = 77(0.125 f t ) 2 0.42 f t = 0.02 ft-^
lb m = 490.75 m
f t '
0.02 f t '
m = 9.82 lb m
where
V = 03 • r
03 = 40 rpm (0.1047) = 4.19 rad
so
so
r = 0.42 f t
V = 4.19 rad 0.42 f t
V = 1.76 f t / s
9.82 lb E, = (0.5) m
3.1 f t ' l b , s'
32.2 lb f t m
E, = 0.47 f t l b .
F = 2(0.47) f t l b .
F-p = 0.94 f t l b , = 1 f t l b .