IMPROVEMENTS IN THE MANUFACTURE OF SUGARS
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
GWYNNE, of Holborn, in the County of Middlesex, Gentleman, and JAMES
YOUNG, of Brick Lane, in the County of Middlesex, Brewer, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-second day of November, in the seventh year of
His reign, did, for Himself, His heirs and successors, give and grant unto us,
the said George Gwynne and James Young, His especial licence, full power,
sole privilege and authority, that we, the said George Gwynne and James
Young, our exors, admors, and assigns, or such others as we, the said George
Gwynne and James Young, our exors, adñors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
our Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SUGARS;" in which
said Letters Patent is contained a proviso that we, the said George Gwynne
and James Young, or one of us, shall cause a particular description of the
nature of our said Invention, and in what manner the same is to be performed,
to be inrolled in His said Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
George Gwynne and James Young, do hereby declare that the nature of
our Invention, and the manner in which the same is to be performed, is
described and ascertained as follows, that is to say :-
Processes, the use of which will make unrefined sugars, whether in a fluid
or solid state, more profitable or valuable than they are at present, and parti-
cularly when such sugars are refined or exhibited in the form of chrystallized
pure loaf sugar. Our Invention is performed partly by the employment of
chemical agents (one of which agents is well known and has been repeatedly
tried in sugar refining, but unsuccessfully) and partly by an improved filtering
apparatus. The juices of the cane, the beetroot, the sugar maple, and
other saccharine vegetable matters contain, besides sugar, several vegetable
principles, as tannic acid (tannin), mucilage, gluten, acetic acid, and other
matters. The presence of these foreign bodies greatly diminishes the quantity
and deteriorates the quality of the sugar produced from such juices. Raw
sugars are also contaminated by very nearly the same impurities as the
juices from which they were produced, with the addition of lime and oxide
of iron, both of which bodies are highly injurious to the color and grain of
sugar. Now the nature of our Invention is,―
First, to render insoluble most of the before-mentioned impurities, and to
neutralize the remainder without the employment of lime potassa (potash)
or soda as a temper."
<
Secondly, to remove the excess of the chemical agent which produces these
effects, along with any lime or oxide of iron, which may be in solution.
Thirdly, an improved filtering apparatus for separating insoluble bodies
from the "clear liquor," (syrup), or juices. We have found by experience that
triacetate of protoxide of lead (subacetate of lead) is the best agent that can
be employed to render insoluble the tannic acid, mucilage, and gluten of
unrefined sugars; it also, from its alkalinity, answers very well to neutralize
any acid or acids which may exist in unrefined sugars.
We now proceed to state the manner in which we would recommend it to
be prepared, and the mode of using it.
Triacetate of Protoxide of Lead.-In a suitable part of the sugar house or
other manufactory, say the floor above where the "blow-ups" or "clarifiers
are situated, let two vessels be placed. These vessels should be of such a
size as each of them to be capable of containing so much triacetate as will
serve for one day's work of the manufactory. The vessels may be made of
copper or wood, lined in the inside with stout sheet lead. The bottom is to be
so shaped as to allow of facility in stirring the protoxide of lead. A steam

page_text: pipe of adequate bore to heat the vessels should be introduced in such a
manner as not to interfere with the stirring. A mouth simply entering them
answers the purpose very well. There should also be a means of guaging the
quantity contained at any time in each vessel. A dipping rod indicating, by a
mark, the number of imperial gallons, will suit the purpose. Say that each
vessel has a capacity of six hundred and fifty imperial gallons, put into each
vessel two hundred pounds of acetate of protoxide of lead (sugar of lead),
eight hundred pounds of protoxide of lead (litharge) in fine powder, and as
much water as will (with the water from the condensed steam) amount to five
hundred gallons. Let the steam be turned on, causing a laborer to stir
constantly until ebullition fairly takes place. After ebullition the vessel should
be allowed to repose until the next day. The solution of triacetate, prepared
as above, should be used as a substitute for lime water or fair water in the
refinery. After the clear solution of the triacetate is drawn from each vessel
the greater portion of the protoxide will be found unacted on. The reason for
recommending this excess of protoxide is in order to procure quickly a saturated
solution. This excess of protoxide is not to be thrown away, but must be used
again. The next operation should be as follows:-Two hundred pounds of
acetate of protoxide of lead, two hundred and fifty pounds of protoxide of lead,
and the same quantity of water as in the first operation, along with the residue of
the first experiment, are to be treated as in the first experiment. This latter
process should be repeated again and again until there is either a troublesome
quantity of carbonate of protoxide of lead (white lead) accumulated in the bot-
tom of the vessel or the triacetate is imperfectly formed. When either of these
two circumstances occur acetic acid should be added until the insoluble matter
is completely dissolved. This solution should now be employed instead of the
acetate in making triacetate. When the triacetaté is properly made it turns the
alkali paper as strongly as lime water. Although we prefer using the triacc-
tate in this diluted state (as a substitute for either the lime water or fair water
required in the refinery to dissolve the raw sugars), it can be prepared in
a very concentrated state if it is desirable to have it so. The following
arrangement will answer the purpose:-A copper vessel of a suitable capacity,
of a globular or oval form, and strong enough to resist the atmospheric
pressure, should be employed. Heat can be applied either from a furnace or a
jacket, into which high-pressure steam can be admitted. The vessel should
have a "man-hole" to allow it to be cleaned when requisite, and a safety valve
large enough to allow the escape of any steam the vessel. is capable of gene-
rating. This valve is to be loaded with a weight which will barely keep it
tight. Some of the diluted triacetate is to be let into the concentrator, and

page_text: heat is then to be applied. The valve keeps out the air by remaining in its
place; as soon as the steam gets some pressure the valve rises and allows it to
escape. When the steam ceases to be produced the valve falls into its place
and cuts off any communication with the atmosphere. As the evaporation
proceeds more triacetate is to be admitted until the desired degree of concen-
tration has been obtained. We would recommend that evaporation should
never proceed so far as to cause precipitation in the fluid. By having a small
stopcock in the vessel the solution can be examined from time to time in order
to guard against this effect. When duly concentrated the solution may be
drawn off into ground-stoppered bottles, and a fresh charge let in. The greater
portion of the impurities of "raw" sugar lie on the outside of the "grain,"
and will therefore be soonest dissolved when water is added to the sugar. We
have found by experience that a thin solution of sugar allows chemical action
to take place in a more energetic manner than a solution of greater specific
gravity. We have also found that if two equal portions of the same "raw" sugar
liquor" be taken, and an equal quantity of triacetate be added to each
"liquor," with this difference, that one portion of "liquor" is first brought to
the boiling point, and its triacetate at once added, and then stirred whilst the
other portion has its triacetate gradually added (in the cold), stirring being
kept up whilst this is doing, and that it is then brought to the boiling point,
the latter liquor" after filtration will prove much freeer from impurities than
the former liquor. Hence, in using the triacetate with "raw sugars, we
would recommend its being let into the "blow-ups" or "clarifiers" in a cold
state, and the sugar to be well stirred in before any heat is applied, or the
sugar put in first, and the triacetate then added and well stirred before heat is
applied. When the sugar is partly dissolved more fair water (in no case
should lime water be used) is to be added until the "liquor" is of the
required specific gravity or "thickness." The "liquor" is to be brought to
a boiling point in the usual manner, and then filtered, in order to separate
the insoluble bodies. In operating on cane juice, beetroot juice, &c., the
necessary quantity of triacetate is to be applied to the juice as it issues from
the mill or press, and is to be gradually poured in, stirring well, until the
whole is added. Heat should not be employed until the triacetate is all in.
When this is performed the juice should be brought to the boiling point, and
then filtered, instead of allowing the impurities to subside by repose. In no
case should lime or any other "temper" be used, as their effects are most
injurious to the sugar. In applying the triacetate to West-Indian molasses
or other impure syrups the directions given as to cane juice should be strictly
followed. It is, perhaps, unnecessary for us to observe that the quantity of
"

page_text: triacetate to be employed will be entirely governed by the amount of impurities
existing in the raw sugar, cane juice, &c., but in no case should more be
added when precipitation ceases to take place in the liquor or juice, which
will be judged of. We have found two and an half imperial gallons of the
diluted triacetate generally sufficient to render insoluble the impurities con-
tained in one hundred and twelve pounds of Muscovado sugar of ordinary
quality; sometimes less has been sufficient. We would advise that a first
trial should be made at the rate of two gallons for each one hundred and
twelve pounds of "raw" sugar. When the liquor is filtered a small portion
should be put into a test tube, and a few drops of triacetate added to the
same, and then well shaken. If after two or three minutes repose no opacity
appears in the glass tube enough has been added, perhaps too much. If
opacity, however, shews itself, it proves that the requisite quantity of triacetate
has not been added. A few trials in this way will soon shew the operator the
proper quantity to be used. Two and an half imperial gallons of the triacetate
will by no means precipitate the entire vegetable impurities from one hundred
and twelve pounds of West-Indian molasses; but we would not advise a
greater quantity than the above to be employed. In applying the triacetate
to cane juice, beetroot juice, &c., we would advise it to be employed so long
as any precipitate is formed. After the requisite quantity of triacetate has
been applied to either raw sugar, West-Indian molasses, cane juice, &c.,
filtration should take place, and the insoluble matters, composed principally of
gummate of oxide of lead, should be preserved, and which, when heated to
redness, will yield protoxide of lead, to be employed instead of litharge in
the making of triacetate. The "clear liquor" or juice now contains such a
quantity of a salt or salts of protoxide of lead that if these salts be not
removed the sugar of such "liquor" or juice will be more injured than if the
triacetate had not been used. In other words, the " grain" suffers more
injury from the presence of these salts of protoxide of lead than the mucilage,
tannic acid, and gluten would have occasioned had the triacetate not been
employed. It is therefore absolutely necessary to remove these salts from tho
liquor" or juice, otherwise the separation of tannic acid mucilage and
gluten from unrefined sugars by the use of the triacetate o protoxide of lead,
instead of being an improvement in the manufacture of sugars, would be a
positive injury. There are several acids, as the sulphuric, oxalic, hydro-
sulphuric (sulphuretted hydrogen) acids, &c., which form insoluble compounds
with protoxide of lead; these agents will therefore get rid of the protoxide of
lead from the "liquor;" but their employment is even more injurious to the
grain than the salts of protoxide of lead which they were intended to remove

page_text: Other chemical agents (as the ferro-cyanuret of hydrogen (ferro-cyanic
acid), phosphate of lime (superphosphate of lime), hydro-sulphate of am-
monia (hydro-sulphuret of ammonia), animal charcoal in fine powder, &c.)
will remove the protoxide of lead, but we have found that there are objections
to their employment, unnecessary here to state. We prefer the diphosphate
of lime (neutral phosphate of lime) or a neutral solution of phosphoric
acid and soda. To any quantity of animal charcoal in fine powder, and
burned to whiteness, add half its weight of sulphuric acid (oil of vitrol),
specific gravity 1.80. The bone ash (phosphate of lime) should have two and
a half times its weight of boiling water well diffused through it, and the sul-
phuric acid should have five times its weight of cold water added to it. When
this is done the bone ash and its water should be added to the diluted acid, and
they should be well stirred together for eight or ten minutes. Stirring should
also occasionally be performed during twenty-four hours, after which there
should be five times the weight of the bone ash of boiling water added to the
mixture, well incorporated, and the whole thrown on a filter, and the clear acid
liquor is to be retained. The insoluble matter left on the filter is to be washed
All
with hot water, and again filtered until the entire acid liquor is obtained.
the different acid solutions are to be mixed together, and from them the diphos-
phate or neutral solution is to be made. To form the diphosphate, a very thin
cream of newly-slacked lime is to added to the acid solution, until the acid test
paper barely ceases to indicate acidity. More lime should not be employed
than will just produce this effect, as otherwise the diphosphate will be seriously
injured. During the time the lime is being added constant agitation should
be employed. The precipitate should be thrown on a filter to drain, and
afterwards should be submitted to hydraulic or other pressure, in order to force
out as much water as possible. Heat should never be used for this purpose.
The neutral solution may be made as follows:-Dissolve a quantity of the
common carbonate of soda in fifteen or twenty times its weight of boiling
water, and add it gradually to the above acid solution from bone ash (stirring
well) until the fluid is exactly neutral.. The whole is to be thrown upon a
filter; the clear fluid is the neutral solution. What is retained on the filter is
to be employed along with bone ash in preparing a fresh acid solution. This
diluted neutral solution should be evaporated almost to the chrystallizing point.
Having detailed the directions required to make the agents which will
deprive the liquor or juice of the salts of protoxide, we will proceed to state a
few observations concerning their employments. Either of these agents will
remove every trace of the salts of protoxide of lead from the sugar, together
with any lime or oxide of iron which might be present. We hardly know

page_text: which of them to recommend as preferable. The operator can choose which
he likes, after being informed of the difference between them. The diphos-
phate is an insoluble body, and more of it must therefore be used than of the
neutral solution. The neutral solution, although itself perfectly neutral to test
paper, sets free a little acetic acid from the tendency of phosphoric acid to
form a triphosphate of protoxide of lead. Now the diphosphate produces no
effect of this kind. Should the operator object to a very simple method of
neutralizing the acetic acid produced in using the neutral solution the
diphosphate should be employed. We have mentioned that this latter body
should be submitted to pressure in order to force out the water. When it is
intended to be used, a quantity of it should be well worked up with some of
the "liquor" or juice containing the salts of protoxide of lead and passed
through a very fine wire sievė, in order to separate any lumps which may have
escaped the working up. It is then to be added to the cistern containing the
clear liquor or juice in sufficient quantity to remove any trace of the protoxide
of lead (after its addition the liquor should be well agitated for a few minutes).
This is easily known by filtering the liquor or juice through blotting paper, or a
little cotton in a funnel, taking a small portion of it in a test tube, and adding
a few drops of the hydro-sulphate of ammonia (sulph. amm. of the apothecary);
on shaking the tube, if there is the slightest portion of protoxide of lead
present, the liquor becomes quite dark in color. A quantity so minute as one
quarter of an ounce in one hundred and twelve pounds of raw sugar turns the
liquor of an inky hue. As the bulk of the diphosphate is diminished in
proportion to the pressure to which it has been subjected, and as perhaps some
persons might not press it at all, it may be as well to state that three quarts
of diphosphate simply drained on a blanket, and not pressed, will generally be
found sufficient to deprive the liquor produced from one hundred and twelve
pounds of Muscovado sugar of all traces of protoxide of lead. The hydro-
sulphate of ammonia is however alone to be relied on. Any excess of
diphosphate is perfectly harmless to the liquor or juice. About a quart of the
neutral solution of phosphoric acid and soda of such gravity as almost to
chrystallize in the cold will generally be sufficient to remove the protoxide of
lead from as much liquor as one hundred and twelve pounds of Muscovado sugar
will make. It should however be treated in the manner directed in using the
diphosphate of lime; no more of the neutral solution should however be employed
than will answer the desired end of removing the protoxide of lead. When
the necessary quantity of either the neutral solution or the diphosphate has
been employed, the "liquor" or juice should be again filtered. It will bo
judicious to have a jacket round the cistern, into which the steam is let in

page_text: order to keep the "liquor" or juice as hot as possible; and if it has been the
diphospate which has been employed the clear liquor or juice is to be imme-
diately converted into sugar in the usual manner employed in the manufactory;
if the neutral solution has been employed it will be advisable to neutralize
the acetic acid which has been set free before boiling the "liquor" or juice
into sugar. The following method we recommend as the best that can be
employed for neutralizing any acid or acids in saccharine matter:-Let a
wooden box lined with lead be made of the following size,-eight feet long,
six feet wide, three feet and an half deep; a stopcock is to put in the bottom
to draw off the "liquor." The bottom is to be covered with a piece of basket-
work, over which a stout blanket is to placed. Fill this vessel to within
six inches of the top, with sand prepared as follows:-A quantity of sand,
about the size of coarse gunpowder, is to be washed quite clean and put into
a suitable vessel, to which heat can be applied (a "heater" or cooler, or of a
vacuum pan, sugar house, is an excellent model). Take a quantity of well
washed chalk (in powder) or carbonate of lime and mix it with a considerable
portion of water, and add the same to the sand. Heat is to be applied, and
occasional stirring. When the water is entirely evaporated away, the sand
will be found covered with a white coating. The clear "liquor" or juice in
which the acetic acid has been set free is to be allowed to percolate freely
through the sand prepared as above, and as soon as it becomes bright it is to be
boiled in the usual manner as practised in the manufactory. A box of the
above size will be found sufficient for a house working ten tons per diem, and
will only require a fresh white coating when the former is dissolved off by the
acetic acid. In applying the triacetate to any impure sugars (as Muscovado
sugar) in the manufacture of which lime or other "temper" has been employed,
there remains a small portion of the vegetable principles which no excess of
triacetate will remove so long as the sugar contains any lime. As long as the
sugar contains any trace whatever of these vegetable principles its chrystal-
lizing power is injured. It is not judicious to remove the lime in the first
instance, but we would recommend the " green syrups" of "raw" sugars
(treated as before directed) to be mixed every day in the "blow-up" or
"clarifier," with proper proportions of raw sugar subjected to the same treat-
ment, and this to be continued as long as refined sugar is produced. When this
latter event occurs the green syrups should then be got rid of in the usual
manner. By following this plan of working the "
green syrups" over again
with "raw" sugar daily used, a much greater weight of refined sugar will be
produced than by any other method. In applying the triacetate to cane
juice, beetroot juice, &c., the "green syrups" should never be mixed again
"

page_text: with triacetate, as there are no vegetable principles to be taken away. They
may be either worked away by themselves or have some fresh juice or sugar
added to them. We would, however, advise that if any time spontaneous
acidity has taken place in the syrups they should be passed through the same,
as before directed. Any refiner who is now using or wishes to use that
process known in London by the name of "Derosne's process," may apply it to
the clear liquor or juice (prepared as we have directed). By following our
directions he will find that one hundredweight of ground charcoal will do as
much duty as several hundredweight is capable of performing with "raw
liquor" so full of vegetable impurities, lime, and oxide of iron, as it would be
if clarified" in the usual manner.
What we claim as the first part of our Invention is the application of (the
different suitable bodies of which phosphoric, pyro-phosphoric, and meta-
phosphoric acids are component parts of these bodies, we give the pre-
ference to) diphosphate of lime and neutral solution of phosphoric acid
and soda, in the manufacture of sugars, where the salts of oxide of lead,
hydrated (precipitated) oxide of lead, or albumate of oxide of lead are
employed as above described. And further when other bodies, such as sul-
phate of soda, acidulated ferro-cyanuret of calcium (prussiate of lime), acidulated
oxalic acid, sulphuric acid, binoxalate of potash, bichromate of potash, &c., are
used for precipitating the oxide of lead, we claim the neutralizing the excess of
such bodies, together with the acid of the salts of lead set free by percolation
through suitable insoluble materials, such as carbonate of lime, carbonate of
magnesia, coarse grained charcoal, &c., as above described, or by binacetate or
triacetate of oxide of lead. Sugar refiners, though accustomed with filtration
on the large scale, appear to be unacquainted with the true principle of con-
structing filters suitable for manufacturing purposes. It is generally held by
them that the more extended the surface the greater is the filtering power,
and to this object all their attention has been directed in trying to improve the
filters (Howard's and Schroder's) now in general use in this country. The
construction of Howard's and Schroder's filters being well known, it is
unnecessary for us to notice them farther than observing, that they have no
way of either increasing or diminishing the surface, they are suited for one
kind of fluid alone, and even for that imperfectly.
Figure 1 represents a front view of our filter. The external parts had,
perhaps, better be made of cast iron, say half an inch thick; the front is
entirely open from top to bottom, except two inches at the bottom to serve for
a cistern; the opening is closed when at work partly by a door and partly by a
strong bar of metal X, with two screws and nuts at each end. This bar

page_text: is about seven inches deep, and extends quite across the box and half way
across the cistern; the door closes the remainder of the opening, and should.
have a packing round it, and some method by which it can be made tight.
when at work; five strong hinges on one side and corresponding thumb screws
on the other side suit well for this purpose.
A box of the underneath dimen-
It is double
sions will contain about one hundred and twenty-five bags, each bag six feet
long and three feet wide, being a surface of four thousand five hundred square
feet. More bags might be put into the space, but that extent of surface will
be found sufficient for any fluid which will admit of filtration.
the extent of a Schroder's filter of the same external size. By means of
small metal wedges the number of bags (and, therefore, the surface) can be
reduced at pleasure; but we would advise that they should not be reduced
below twenty-five bags, as the opposite extreme of diminished surface. Di-
mensions internally of a one hundred and twenty-five bag filter, six feet six
inches deep, three feet two inches wide, five feet long. Besides this size there
is a small cistern at one side (marked A). It is from this cistern the liquor
runs into the bags. The inside measurement of the cistern is five feet long,
six inches deep, and nine. inches wide. In constructing filters, we would
recommend that they should be made in pairs. By this means the cistern in
one box can be on the right side, in the other box on the left side, having only
one partition between them. Figure 2 shews the filter in section and cistern
more particularly. Fig. 3 is a plan of the same. Fig. 4 is a side view. C
is the groove or opening through which the wedges (these wedges and their
use will be described presently, are introduced. G is the aperture through
which the liquor flows off when too great a depth would be in the cistern.
K is a bar of metal which, by means of two screws, forces down the wedges in
the groove. N is a slide valve, by which the flow of liquor into the bags is
regulated. R is a pipe perforated as full as possible with holes about the ono
sixteenth of an inch in diameter. This pipe is for the purpose of stopping
any nails, pieces of hoop, &c., which may be in the sugar, and which in lodging
about the slide valve might prevent it acting properly. The groove or opening
C is made exactly of the same shape as the wedges, and extends from the
front to the back of the cistern. The lower side of the groove, which is firmly
screwed to the side of the box, must be filed or ground perfectly flat, and have an
angle corresponding to the wedges. It is sunk three eighths of an inch below
the bottom of the cistern, in order to carry off the liquor completely. It must
also extend four inches beyond the front of the cistern, in order to afford a
resting-place to the wedges when screwed up by the bar X. The bar of
metal K has its lower face filed or ground to an angle corresponding to the

page_text: wedges. It runs the entire length of the cistern, and is one inch in thick-
ness and four inches deep. A piece of metal at either end, three-eighths
of an inch square, covered with flannel, and screwed to the front and back of
the cistern, retains it in its place and makes it quite tight at the ends.
These pieces also serve as packings to one side of the slide valve. The
bar has an ascending and descending motion by means of two screws, of
say half an inch. The slide valve N runs the cistern lengthwise. It is, say one
inch thick and six inches deep, and has an ascending motion of two inches;
it must be perfectly flat and tight on the lower face when screwed down; it
is made tight at the ends by similar pieces of metal covered with flannel, as
mentioned above. The pipe R also runs lengthwise of the cistern; it is about
three inches and a quarter in diameter, open at both ends, and is kept in its.
place by means of side pieces; it is intended to be removed when required, in
order to be cleaned of any dirt which might choke up the holes. The cistern.
either at front or back has an opening cut in it corresponding to the diameter
of the pipe. This opening is connected with the cock or cocks of the blow-ups,
and through it the liquor enters the cistern. The pipe lies midway between.
the slide valve and the opposite side of the cistern. The aperture G is one
inch from the top of the cistern; it is connected by suitable means with the
"foul liquor" cistern in order to carry off an undue pressure of liquor. In the
box along the two sides, lengthwise, are two slips of metal T on each side,
forming two grooves. These grooves are to support the bags and separators.
The upper slips are an inch and an half from the top of the box, firmly
screwed to the sides, and run the exact length of the box, from front to back;
these slips are perforated right up the middle with one hundred and twenty-
five holes. Into each hole is rivetted a piece of brass or iron wire, one eighth
of an inch in diameter, and rising half an inch high; these pieces of wire are
for holding the loops of each bag. Half an inch below the above slips are
screwed the two lower ones; these lower ones extend four inches beyond the
front of the box in order to afford support to the separators when screwing up.
All these slips are seven eighths of an inch wide by half an inch deep. Two
inches and an half from the bottom of the box are placed two bars (one on
each side) of metal perforated with about one hundred and twenty-five
holes, each hole capable of taking a piece of wire one eighth of an inch in
diameter. These bars run the length of the box, and are seven eighths of an
inch at the back, six eighths at the front, and seven eighths wide, and firmly
screwed to the side, and have the difference in thickness on the upper side
alone. The outsides of the holes are an eighth of an inch from the front of the
bar. The pieces of wire are four inches long; these pieces of wire are slipped

page_text: in and out of the holes when required, and are for retaining the bags in their
places at the bottom. It is perhaps needless to observe that the box requires
cocks, air, and steam pipes in the usual manner. It will also be advisable
to have moveable covers for both the box and cistern, in order to prevent the
cooling of the liquor. It will presently be perceived that our filter has only
a pressure of a column of liquor of half an inch above the bags, any pressure
required, however, can be obtained having no aperture G, and a cover on
the cistern, capable of being made tight. Our opinion is however against any
pressure above the tops of the bags, as only tending to wear them out
prematurely.
Figure 5 represents a bag suspended. Figure 6 represents a separator
suspended. Figure 7 represents a front view of one of the hollow wedges
through which the liquor is admitted into the bags, and Figure 8 represents a
side view of the same (Figure 5). a, the hollow wedge; b, b, the loops at
top; c, c, the loops or chains at bottom. Each bag has a piece of stout
whipcord, say three thirty-second parts of an inch in diameter, run in round
its mouth, and of this cord is made a loop at each side. These loops are each
about three fourths of an inch long. The general mode of sewing bags,
(what is called "running and felling" up to the sides) should not be done
here quite to the top of the bag, but a space of an inch left, which is to be
strongly sewed in order to lie quite flat when pressed by the bars of the
separators, and the mouth of the bag is to be closed or sewed up for about two
inches at each side of the bag, and thus contract the length of the mouth.
The hollow wedge a is fastened to the bag by a tube formed out of a double
piece of the same cloth as the bags. This tube is made to fit the wedge
tightly. It extends three inches from the bag, and its upper side is one inch
and an half from the top of the bag. The seam of the tube should lie on the
upper side of the wedge, which should have a slight groove in it in order to
allow the seam to be quite flat.
Figure 4, a separator, which is simply a piece of very coarse hair cloth.
Very strong sampler canvas will answer the same purpose. Or, in place of
using separators, the bags may be made of a cloth with ribs projecting from
the outer surface, by making part of the warp of strong twine, three thirty-
second parts of an inch in diameter, each cord half an inch apart, and warping
with ordinary cotton between in the usual manner for making strong twilled
cotton. By this means a corded fabric will be obtained, the projecting
surfaces of which will act as separators, and then a plain bag and a corded
bag may be used alternately. A piece of cloth (same as the bags) is strongly
secured to the hair cloth such a depth from the top (say three inches) as will

page_text: not tear off in using. In this cloth, in a string case, into which a piece of
tinned iron thirty-seven inches and three quarters long, seven sixteenths of
an inch thick, and half an inch deep, is sewn. This piece of metal serves
two purposes, videlicet, it closes completely the mouth of the bag, against
which it presses, and also suspends the separator. The separator should be the
same width as the bag, say, three feet, and the "hem," which keeps it from
unravelling at the bottom, should be three quarters of an inch below the bag
when suspended; (that is to say,) the bag is six feet long, and the hem of the
separator is one inch deep. The entire length of the separator, including the
string case" at the top, may, therefore, be six feet two inches.
.
Figures 5 and 6, the hollow wedge. It is formed of brass or iron, and is
two inches long at top, one inch and thirteen sixteenth parts of an inch long
at bottom, one inch deep, and seven sixteenths of an inch thick. It has two
apertures right through. Each aperture is half an inch long and a quarter of
an inch wide. The remainder is solid. There are three small holes drilled
through the solid parts, by which it is sewn into the tube before mentioned..
There are also a number of small wedges, exactly the same size and shape as
the hollow ones, covered with a double piece of cloth. These are for the
purpose of diminishing the surface of the filter. There must also be a number
of pieces of tinned iron (covered with cloth also) of the same size as those
mentioned in describing the separator. These also are required when the
surface of the filter is to be diminished.
Having now described the different parts of the filter, we will briefly explain
the manner of setting it to work, and the method of either diminishing or
increasing the surface. We will suppose, in the first instance, it is to be set
to work with one hundred and twenty-five bags. The bar K, Figure 2, is to
be screwed up a little in order to allow the wedges to be entered into the
groove C. A separator is shoved right to the back of the box, its bar being
in the grooves formed by the slips of metal. A bag is now hung by the top
loops on the wire on either side, and fastened at the bottom by slipping in the
pins through the holes and loops, the wedge being at the same time entered
into the groove C quite to the back of it. Another separator is put as before,
bag as before, and so on till the box is quite full. When this is the
case the wedges and bars of the separators are firmly screwed together by
means of the strong piece of metal X. The bar K also is firmly screwed
down on the wedges. Now by this downward and lateral pressure the wedges
become quite impervious to the liquor in the cistern except through the hollow
parts. The slide valve N should be shut until the liquor in the cistern, which
enters through the pipe R, has risen and inch above it. When this is the
case the slide valve is raised just so much as to carry away the liquor from the
then a

page_text: cistern as fast as the cock of the "blow-up" can supply it. Care should be
observed to keep the pipe covered with liquor by regulating the valve, as it is
desirable that the same quantity of liquor should enter each bag in equal
times in order to prevent unequal depths of liquor in the bags. Second
case-When the surface is required to be diminished, a separator is to
be put in as before; a solid wedge placed in the groove; a bag placed as
before, and then a tinned bar covered with cloth (as the bars of the sepa-
rators), to which no separator is attached; then another solid wedge is put
into the groove, another separator is put in, and then a bag, and so on until
the box is full. These two cases will plainly shew the method of diminishing
the surface to any extent required. We would recommend that the cloth of
which the bags is fabricated should be well boiled in water, dried, and
'mangled" before being made in order to have shrunk as much as they will.
It will also be advisable to dip the material of which the separator is made in
boiling water before being cut to the proper lengths. It is essentially
necessary that the hollow wedges should be exactly of the same size, and have
their openings exactly in the same line, and lie exactly horizontal.
We only claim the application of flexible substances, as hair cloth and other
suitable flexible fabrics between filtering bags, or forming bags of corded cloth
which produces the necessary separation of one bag from its neighbour,
whereby very extensive filtering surface may be obtained in a small space for
the purpose or processes pursued in the manufacture of sugars.
In witness whereof, we, the said George Gwynne and James Young,
have hereunto set our hands and seals, this Twenty-second day of May,
in the year of our Lord One thousand eight hundred and thirty-seven.
GEORGE GWYNNE. (L.S.) JAMES YOUNG.
AND BE IT REMEMBERED, that on the Twenty-fifth day of May, in
the year of our Lord 1837, the aforesaid George Gwynne and James Young
came before our said Lord the King in His Chancery, and acknowledged
the Specification aforesaid, and all and every thing therein contained and
specified, in form above written. And also the Specification aforesaid was
stamped according to the tenor of the Statute made for that purpose.
Inrolled the Twenty-second day of May, in the year of our Lord One
thousand eight hundred and thirty-seven.