Polynesian., 1853-02-12

nous constituents and feculent matters wi
have been coagulated and chemically sepa
rated, but will, of course, still remain me
chanically mixed, and, in the form Of ligt
flock, pervade the entire bulk Of the fluid
These substances are then effectualIy re
moved by a process similar to that employe
in the manufacture of paper. A drum Q
about two feet in diameter, and from four t.
five feet in length, is made to revolve slowl
in small sem-circular tray, or vessel. Thi
drum is covered with fine wire cloth, ihrougl
which the water forces its way. leaving
muddy coating Of extraneous matters OH th'
outer side, which, coming in contact, as
revolves, with fixed scraper, similar in prin
ciple to the doctor " employed in calico
printing, is made to fall off, in a state some.
thing like dry mud, into a receptacle prepa
red for it. The process is self-acting Il
takes in its own supply of foul liquor from ar
elevated cistern, delivers the clear juice into
the evaporating pan, and discharges the re-
fuse as we have already stated.
Up to this stage the advantages obtained
must be evident to all who are acquainted
with this interesting branch of manufacture.
The liquor being received direct from the
press, avoids the necessity of the use of
liquor pumps; the clarifers, not being used
as subsidlng vessels, are not required to be
large; the loss of juice in the removal of the
scum and in the sediment is prevented; the
use of the I" montjus % is rendered unneces-
sary; the coagulation of the abuminous mat
ter is more rapidly obtained the evaporating
process may follow Immediately after the
pressing of the canes; and finally, the self
cleansing filter performs its work much bet
ter than any continuous process of skimming,
and renders unnec ssary that watehful at
tendance which is now so imperatively ne
cessary in order to obtain the required bright
ness and color Of the sugar. The saving of
manual labor by these improvements is self
evident.
On the various modes of boiling and con-
centrating the juice at present in use, whe-
ther by series Of semi-glObular pans, the
vacuum pan, Gadsden's pan, or the appara-
tus of MIR. Crossley or MIR. Schroeder, it is
not necessary now to speak, the principle
involved in one and all of them being the
sane-that of evaporating the fluid from the
saccharine matter. The inventor of the pro-
cess now under consideration, contends that,
IN all the existing arrangements for the sepa-
ration Of the water from the sugar, boiling
under any form, or the use of surfaces or
pipes heated by steam, must be totally excIu-
ded if the formation of molassses is to be
prevented. 1t is a well established fact, that
a thermometer placed in solution heated by
steam or the direct action of fire, furnishes
no indication of temperature to which the
liquid IS exposed, as vast amount of latent
heat is absorbed by fluids in their formation
into steam. To the forgetfulness of this sim
pie fact are TO be traced many of the fatal
mistakes at present connected with the man
nfacture of sugar.
Thus, while the temperature of the syrup, |
Turing ebulition in avaccuumpan, indicates
Is low perhaps as $50 degrees Fahrenheit
he copper worm, against which portions
he sugar are constantly brought into contact
5 equal to, and often above 22O degrees
the consequence of which is the
destruction of the color, and an injury to the
;rystallizing powers of the sugar By an
which Mr.. Bessemer terms a
lot air evaporator, the concentration of sac
harine fluids may now, however, be effected
without the slightest injury to color or quail
y, and in an increased quantity.
The apparatus consists of tank of thin
late IRON, oe about ten feet by eight feet,
md D feet in depth. which has false bottom,
severed so as to form two parallel segments
# cylinder. Above these and coincident
With them is hollow drum, Of eighteen in
hes in diameter, mounted on an axis, and
pon which is formed a broad spiral blade, in
he shape of a screw, or creeper," the
bread Of which is about fifteen inches in
ep::ihi, and the convolutions three quarters of
n inch apart; and between each of the Z
ladies' or threads of the screw, holes are t
ormed spirally from one end Of the drum to I
he other At one end of the hollow drum,
r. supplied by blowing fan, and heated to {
so degrees by passing along iue, is made s
0 enter, which escapes through the holes in
he drum in a radial direction, and sweeps {
Ike the hot breath of the simeon over the
vet surfaces OF the various revolving blades, L
bsorbs the moisture thus exposed to its ac-
ion, and passes off in an invisible vapor.-ls
Upwards Of six thousand square feet of evap- /
rating surface is thus obtained in the small
pace Of ten feet by eight. The screws make
bout eight revolutions per minute as they Il
evolve, the more concentrated portions Of
he fluid are washed off as they descend in il
D the fluid, and fresh portions are being con-
tantly brought up on the surface ofthe screw
D be in like manner subjected to the hot air
last Finally after three or four hours, the
,hole OF the surplus liquor is carried off;
he remaining fluid is sufficiently concentra-
ed, and assumes a thick gellatnous appear
nee; and the screw made to revolve in the
pposite direction, expels the solution from
ne tank ready for the process of crystallza- b
on By this process, the sugar is not at il
ny time exposed to hotter surface than lao s
egrees No boiling consequently takes 4
lace, no slea is formed, and not one grain h
f crystallizable sugar is converted into mo- b
,sses. The entire cost Of fuel for evapora- o
on is saved, the waste heat of the chimney Ic
nd waste steam Of the engine being alone d
mpIoyed, and the apparatus costs less than C
ne ordinary vapor pans; it can be worked v