NEW AND IMPROVED PROCESSES AND MACHINERY FOR MAKING AND REFINING SUGAR
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
JOHNSTON, of Willow Park, Greenock, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Thirty-first day of January, in the eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the."
said James Johnston, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said James Johnston, my
exors, adñiors, or assigns, or such others as I, the said James Johnston, iny.
exors, adiñiors, 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, and in the Isles of Guernsey,
Jersey, Alderney, Sark, and Man, and in all Her said Majesty's Colonies.
and Plantations abroad, my Invention of "NEW AND IMPROVED PROCESSES AND
MACHINERY FOR MAKING AND REFINING SUGAR;" in which said Letters Patent is:
contained a proviso, that I, the said James Johnston, shall cause a particular
description of the nature of my said Invention, and in what manner the samo..
is to be performed, to be inrolled in Her 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, I, the said
James Johnston, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, that is to say:-
A syrup made from double refined loaf sugar is perfectly free from colouring
matter, yet if it be for a short time exposed to excessive heat it becomes dark,
and will not again crystallize, or if it be long exposed to gentle heat, the same
result occurs. Now, in either case the colouring matter produced was not a
substance foreign to the sugar; it was a part of the sugar that was actually
converted into colouring matter. Sugar refiners, in making use of large sized
vacuum pans, overlook the fact that they become colour manufacturers when
they keep their saccharine fluids long exposed to the action of gentle heat. In
these large pans the saccharine fluids are kept longer under the influence of
heat than they are when boiled in small pans.
The sum and substance of the Inventions which I am about to describe in
detail is, that I have invented an apparatus by which saccharine fluids may be
evaporated sufliciently for crystallization with only a few minutes' exposuro to
heat. In my vacuum pan there need not be inserted at one time more than
fifty pounds weight of saccharine fluid, and yet a large business in sugars may
be done with this small apparatus, as there is no time lost in filling or emptying
it, as the vacuum is never injured either by the letting in or withdrawal of the
charge from the pan.
The first part of my Invention I shall describe is an apparatus by which
vacuum pans may be emptied without the vacuum being destroyed. I attach
a pipe to the bottom of a vacuum pan, so that the saccharine fluids within the
pan can freely enter the pipe, and the pan may be emptied thereby; I call
this the barometer pipe, it must be made of such length that the weight of the
saccharine fluid within it shall counterbalance or rather exceed the weight of
the atmosphere, so that when a stop-cock at the bottom of the pipe is opened,
the saccharine fluid within the pan will of its own weight rush out by the pipe
till the pan is emptied, but the pipe will remain filled with saccharine fluid, in the
same manner as a common barometer tube remains full of mercury. The pipe
for this purpose will be upwards of twenty-five feet long; the length of pipe
required depends on the specific gravity of the saccharine fluids after they are
boiled, the heavier the fluids the shorter the pipe may be made. The preceding
is the least expensive method of emptying a vacuum pan without destroying
the vacuum; but as it may not always be convenient, instead of the barometer
pipe, a pump may be attached to the pan for the purpose of removing the

page_text: saccharine fluids without destroying the vacuum, but I prefer the barometer
pipe when it can be conveniently used.
I claim the making and using of vacuum pans with apparatus attached, so
that the contents of the pans may be withdrawn without the vacuum within
the pans being destroyed.
Second part of my Invention. All liquids, but especially thick saccharine
fluids are most easily evaporated when distributed in thin strata. For the
purpose of carrying out this system of evaporation several machines have been
contrived, the earliest invented was Mr. Cleland's, described in his Patent of
> Seventeenth of August One thousand eight liundred and twenty-two, and Sixth
of May One thousand eight hundred and twenty-four; also Mr. Aitchison's
Inventions, patented Fifteenth September One thousand eight hundred and
twenty-nine, and Twenty-fourth June One thousand eight hundred and
forty...
As I have invented an apparatus for the same purpose, I shall describe the
difference between it and those that have already been made public.
Mr. Aitchison's apparatus consists of a hollow cylinder of copper heated
internally by steam. It is made to revolve in a trough containing a quantity
of saccharine fluid; the lower half of the cylinder being immersed in the flui
when the cylinder is set in motion, a thin layer of fluid goes round with it. It
is this distribution of. the fluid on the surface of the heated cylinder which
causes the rapid evaporation.
Mr. Cleland in his Invention used a spiral heated coil of pipe instead of the
cylinder employed by Mr. Aitchison..
The sugar made by Mr: Aitchison's apparatus is superior in color, size, aud
firmness of crystal to that produced by the vacuum pans, but the misfortune
with the Inventions of Messrs. Cleland and Aitchison is, that a large business
in sugars cannot be done with them, owing to the loss of time cccasioned by
the necessity of frequently filling and emptying the troughs.
:
I obtain a thin strata of fluid on a heated metallic surface by causing a
stream of the fluid to run down an inclined plane heated by steam. For the
sake of explanation, suppose a flat table of twenty feet in length and two feet
broad, made of two thicknesses of metal, so that steam may be made to pass
through internally from end to end and heat the table; also that the pipes:
which convey the steam to the interior of the table be flexible or jointed, so:
that one end of the table may be elevated at pleasure. When one end is
raised this tablo. will serve as an inclined plane on which to cause a thin
stream of saccharine fluid to run from the upper to the lower end, and in so
doing, the fluid will be evaporated, owing to its being made to run over the

page_text: heated surface. The long sides of the table or plane must be provided with
raised edgings to prevent the fluid running off at the sides. The thickness of
the strata or quantity of fluid made to pass along the inclined plane is adjusted
by a stop-cock on the pipe (connected with a cistern), which lets on the fluid
at the top of the plane; at the lower end of the plane the concentrated fluid
runs into the coolers without interruption; when one cooler is filled the con-
centrated fluid may be directed into another without any stoppage of the
evaporating process, and consequently there is no loss of time in working the
inclined plane. The degree of concentration of the fluid is obtained according
to the degree of inclination at which the plane is set; when the plane is set
with very little inclination the fluid will take longer time to go from the high
to the low end, and consequently it will be denser as it is longer exposed to
the heat. After these inclined planes have been used for some time on the
large scale the sugar refiners will find out by experience the angle of inclination
which answers best, and will be able to do away with the flexible pipes.and
the necessity for altering the angle of inclination of the plane; they will then
regulate the degree of concentration.of the saccharine fluids by the quantity of
fluid let on to the plane in a given time, and by the degree of heat applied to
the plane during that time. I do not confine.niyself to any particular dimen-
sions or kind of material used in the construction of the inclined planes, but
cast iron or copper are the most suitable. Steam, l'ot air, or any other heating
medium may be employed to heat the planes.
- ?
I claim the evaporating of saccharine fluids by distributing them in their
strata, when the said thin strata is obtained by causing the saccharine fluids to
run by their own weight from the high to the lowe end of heated inclined
surfaces, whether curved or plane.
The third part of my Invention which I claim is a combination of the first
and second parts of my Invention; described as follows:-The second part of
my Invention consists of an apparatus for the evaporation of saccharine fluids
whilst exposed to the pressure of the atmosphere. Now, it is quite evident
that the thin strata of fluid, whilst flowing along the inclined plane, would be
still more quickly evaporated if the pressure of the atmosphere could be kept
off it. For this purpose I propose to cover the inclined plane with a strong
metallic arched covering that will be able to resist the pressure of the atmo-
sphere. Suppose this to be done, and a communication by means of pipes be
made between the covering on the inclined plane and the vacuum pump of a
sigar house a vacuum may now be formed in the space between the inclined
plane and the covering; the thin strata of saccharine fluid running along the
inclined plane will now be in a vacuum, and its evaporation accelerated thereby:

page_text: But the working of an apparatus like this could not be carried on any length
of time without interruption, for the stream of saccharine fluid let on to the
inclined plane would very soon fill up all the space between the covering and
the plane, and the apparatus would be rendered useless for the time being;
it is therefore necessary that some provision be made by which the concentrated
fluid may be withdrawn from the plane without the vacuum being destroyed.
This I propose to do by attaching to the lower end of the plane a pump, or
the barometer pipe already described. With an apparatus constructed like
this, the process, of concentrating saccharine fluids may be carried on without
interruption for any length of time, as the supplying of the fluid through a pipe
and stop-cock at the high end of the plane, or the withdrawal of the concentrated
fluid by the barometer pipe at the lower end of the plane, will cause no inter-
ruption to the vacuum or process of evaporation, and the saccharine fluid.is
only a short time exposed to the action of heat, for the whole of it on its
passage along the plane is exposed in thin strata; whereas in
any other appa-
ratus that has yet been invented for the evaporating of saccharine fluids there is
always a large mass of the fluid kept in a heated state, which is not in contact
with the vacuum, where the most rapid evaporation takes place. For instance,
in the vacuum pans the whole contents are kept heated, whereas only one part
out of a thousand of the heated fluid is actually in contact with the vacuum.
Evaporation in vacuum pans is produced by two causes: first, the evaporation
by vacuum; second, the evaporation by heat. To increase the heat-evaporating
power of a pan it is necessary to increase the amount of surface of heated
metal in contact with the fluid to be evaporated. To increase the vacuum-
evaporating power of a pan it is necessary to increase the amount of surface
of the liquid that is exposed to the vacuum. The two causes of evaporation
are quite distinct; but in order to prevent any misunderstanding, be it under-
stood that when a sugar refiner inserts a number of steam pipes through the
mass of saccharine fluid laying in a vacuum pan he is subdividing the fluid for
the purpose of bringing it more intimately in contact with the heating surface,
but he does not thereby bring it more intimately in contact with the vacuum
surface.
I claim the Invention of exposing to the influence of a vacuum, saccharino
fluids in a state of minute division or thin strata, for the purpose of bringing
a large amount of the surface of the fluid in contact with the vacuum.
The fourth part of my Invention.-When filtering saccharine fluids, sugar
refiners pass them through cotton or woollen bags, in order to remove the
particles of extraneous matters that are mechanically suspended in them; they
thien pass the fluids through beds of animal charcoal, in order to remove the

page_text: colouring matters chemically incorporated with them. Instead of the bags
for removing the mechanically suspended colouring matter, I claim the passing
of saccharine fluids through beds of mineral substances unprepared, such as
sand or earths, or through prepared minerals, such as potters' refuse, unglazed
earthenware, or pounded bricks.
In witness whereof, I, the said James Johnston, have hereunto set my
hand and seal, this Twenty-fourth day of July, in the year of our Lord
One thousand eight hundred and forty-five.
AND BE IT REMEMBERED, that on the Twenty-fourth day of July, in
the year of our Lord 1845, the aforesaid James Johnston came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form abovo
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Thirty-first day of July, in the year of our Lord One
thousand eight hundred and forty-five.

page_text: En the Matter of a Patent granted to JAMES JOHNSTON, of Willow
Park, Greenock, Engineer, for his Invention of "NEW AND IMPROVED
PROCESSES AND MACHINERY FOR MAKING AND REFINING SUGAR," bearing
date at Westminster, the Thirty-first day of January, One thousand
eight hundred and forty-five, and to which a Specification has been
duly inrolled.
DISCLAIMER proposed to be entered by James Johnston with the Clerk
of the latents of England, pursuant to an Act passed in the fifth and
sixth years of the reign of IIis late Majesty King William the Fourth,
intituled "An Act to amend the Law touching Letters Patent for
Inventions."
I, the said James Johnston, do declare that since the inrolling of my said
Specification I have discovered that the second, third, and fourth parts of my
Invention are not new, for which reason I wish to disclaim, and I hereby do
disclaim all parts of my said Specification which relate to or in any way
describe such second, third, and fourth parts of the Invention; and as the title
originally given to the Invention will be too large for the Invention which will
then remain, I for that reason alter the title by striking out the words "new
and," and also the words "processes and" from the title, so that the title which
will then remain will be "Improved Machinery for Making and Refining
Sugar."
In witness whereof, I, the said James Johnston, have hereunto set my
hand and seal, this Tenth day of January, in the year of our Lord One
thousand eight hundred and forty-eight.
To the Clerk of the Patents of England.
This is to certify, That James Johnston, of Willow Park, Greenock,
Engineer, has applied to me for leave to enter with you the above-written
Disclaimer of a certain Invention, for which Letters Patent were granted to
him on the 31t day of Jan 1815, and to which a Specification was duly
enrolled. And having considered of the said application, and no objection
Laving been made to the same, I have accordingly granted leave to the said

page_text: James Johnston to file with you his Disclaimer, pursuant to the Statute passed
in the 5th and 6th years of the reign of His late Majesty, entitled "An Act to
amend the Law touching Letters Patent for Inventions.
Enrolled the Seventeenth day of January, in the year of our Lord One
thousand eight hundred and forty-eight.