The Hawaiian gazette., 1885-06-10

| extract rs much juice from them III proportion as
would the same pressure applied TO thinner body
| OF canes.
| To make the matter more explicit and to use
| figures that about apply to scores of mills in use
| III our own State, will say that mill with toI
roller shaft Of eight inches diameter has housing
| and mill gearing to correspond, and will readily
exert pressure of 100 tons with entire safely to
the mills and gearing. This mill will grind feed
| of cane inches thick, inches thick or inches
thick If II be 70 inch mill turning three revOlu-
! tons per minute, the surface movement will be
about 20l feet per minute. At this speed 100 tons
pressure viii do but poor work on feed six inches
thick. 1t will do fair work on feed four inches
thick. il will do excellent work on feed two in
| ches thick. Experience has thus led us toward a
regular thin feed for the best results with given
pressure, and this conclusion has perhaps led to
another, and that is, that thin feed with rapid
speed Will give better extraction than thick feed
with slow speed the pressure in each case being
the same. Those planters who got good extrac-
ton only when they carried heavy feed, find that
their mills are not so adjusted rs to allow them to
exert the same pressure on thin feed and herein
lies the cause Of many mistakes concerning juice
extraction.
If we start then, with the proposition that we
should IN no case tax the strength of our cane mills
beyond their probable capacity, and, to continue
our illustration, If that be limited to 100 tons, we
should then determine how thick feed the mill
| will successfully crush under this strain.
Without claiming to be exact, / should estimate
such mill, with surface speed of, say twenty
feet per minute, with even feed three inches
thick, TO grind 80 tons of cane per day of twenty
four hours, extracting about sixty per cent, of
juice "a single mill, or seventy per cent, if dou-
bic mill, with 100 tons pressure on each mill.
If this 100 tons pressure could be applied TO each
single cane, OF course much higher extraction
would be reached, but as we want working data |
have assumed the three-inch feed, and speed of
twenty feet per minute To properly grind feed
of cane thin this il is usual to have the rollers
screwed up iron TO iron, the spring of the mill
| bolts then allowing space enough for the passage
of the bagasse.
Under these conditions irst-cass work is done,
but experience has shown the practical impOssi-
blllty of maintaining Il uniform feed. With less
feed than the standard the spring of the mill bolts
allows too much space and bad work is done.
With more feed than the standard the engine
statS, or the gearing or the mill breaks, or the
works. done under peTiOus conditions that we are
all striving 10 avoid.
For the poor results of toe thin a feed there has
heretofore been no remedy, excepting the use of
heavier and more rigid mills, in which there could
! be but little If any spring of the bolts. This
seemed an expensive remedy to apply whore but
little work was to be done, and where economy in
the outfit was essential.
For the disasters resulting from too thick feed
there has heretofore been remedy, except to in
crease the strength of each part when broken.
This increased strength gives increased confidence
and usually the feed Is increased and the chapter
OF disasters Is again repeated; and this has gone
on from year to year until now we feel we can no
longer endure il.
tAI rev persons dppIeCldle the enormous strain
upon cane mill by an excessive feed. 1t must be
crushed, ground to powder and go through, or the
mill must stop or break. Even for ordinary work
our cane mills must have double the strength
ordinarily used, and they frequently have three or
four times the strength ordinarily used, and yet
give way when suddenly halted by an excess of feed
II all this strength, unused except in the emer-
gency OF excessive feeding could be constantly ap
pied to the extraction of cane Juice. we should
enormously increase that extraction; and herein
develops the merit of the Mcdonald hydraulic
pressure regulator. Having determined Just what
pressure you think your gearing and mill will
safely stand. your top roller is loaded with that
weight, and there it remains constantly. Ii there
be no feed in the mill the one hundred tons or
moro hang on to the bolts all the time and main
tam the tension, taking up all of the spring in the
bolts and the less the feed the better the bagasse
If but one cane goes through, the one hundred or
more tons Of pressure are concentrated on it. The
larger the feed the less good is the bagasse, be-
cause You are exerting thereon your standard pres
sure Of, say 100 tons, and now you begin to insist
on no excess of feed, but to cOuntenauce Occasio-
nal deficiencies IN feed, the thin spots give the
highest extraction.
Surely this is q revolution in our industry
Heretofore TO apply one hundred tons pressure we
had to have strength up to three hundred or four
h1ndred tons; and fearing breakage, we applied
not over sixty or seyenty-tiye tons pressure most
of the time; thinner feed, through a rigid open
ing, of course, developing less pressure. Now,
when we want to apply one hundred tons pressure
1t Is there all the timeneyer less be the feed ever
SO thin, and never greater, matter how thick the
feed may be, for the device works easily and the
thicker feed simply opens the rolls and passes
through with no more strain than with the thin
feed.
believe there is not a cane mill in Louisiana,
except those now using the hydraulic device, that
does not at some time every day in the grinding
season, stand double its ordinary strain. IL thew
have, then, this double strength lying ready for
emergencies, why not do away with the emergen-
cies and use the double strength all the timer You
can thus double the average pressure exerted by
every cane mlu II Louisiana. An old cane mill
with the hydraulic device, is better than some
what larger new one without it. II will give 4
higher percentage of extraction. Whatever capa-
city or strength the cane mill has is utilized ell the
time. There ere no periods of light pressure, of
light work. and>One of the noticeable results Is the
increased consumption of fuel at the mill builers
required by the increased work of the mill
Tor some ten years past have used a double
mill, and IN previous years never exceeded sixty
eight per cent, average extraction for an entire
campaign During the season recently ended
ground over 1000 tons Of cane, and obtained an
average extraction shade above seEenty-two per
raut Tins a frrfr of ol,o