IMPROVEMENTS IN APPARATUS FOR EVAPORATING AND BOILING SACCHARINE LIQUORS
Year: 1867

page_text: LETTERS PATENT to Walter Knaggs, of No. 5, Euston Grove, Euston
Square, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN APPARATUS FOR EVAPORATING AND BOILING SACCHARINE LIQUORS."
Sealed the 25th June 1867, and dated the 3rd January 1867.
PROVISIONAL SPECIFICATION left by the said Walter Knaggs at the
Office of the Commissioners of Patents, with his Petition, on the
3rd January 1867.
I, WALTER KNAGGS, of No. 5, Euston Grove, Euston Square, in the
County of Middlesex, do hereby declare the nature of the said Invention
for IMPROVEMENTS IN APPARATUS FOR EVAPORATING AND BOILING SACCHARINE
LIQUORS," to be as follows:-
My new mode of evaporating cane juice or sugar solutions consists in
allowing it to boil in a tray or in a succession of trays so that it may pass
over its or their surfaces in a shallow stream, and being admitted continuously
at one end of the tray or series of trays it will gradually flow on during
ebullition and make its escape at the opposite extremity in a concentrated
state of a greater or less density according to the length of the tray and the
heat applied. The depth of the liquor in the tray is regulated by adjustable
rims placed at the ends of the tray or trays. The surface of the tray or trays

page_text: will by this means always be covered with an even depth of liquor. I prefer
to make this boil by fire or by steam applied to the bottom of the tray or
trays; in the latter case by means of a suitable space below it, and to
increase the heating surface acting upon the juice by the insertion of a row
of steam tubes placed along the bottom of the tray, such tubes communicating
with the steam space below. This apparatus may be made to boil by means
of steam from a separate boiler, but I prefer making it generate its own
steam by placing it over a fire and filling the space below the tray to a
suitable height with water; it then becomes a steam boiler, the heating
surface of which may be increased by any of the known arrangements for
that purpose. By this means, owing to the small depth of liquor exposed to
its action, very rapid ebullition will take place, and as the tray will always be
covered to a sufficient depth burning or charring of the sugar will be
impossible, while the shortness of the time during which the sugar will make
its passage through the tray in a state of ebullition will effectually obviate
the occurrence of any chemical decomposition and consequent deterioration.
This apparatus is to be fitted with a double cover, by means of which the heat
contained in the vapour generated by its action may be utilized.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Walter Knaggs in the Great Seal Patent Office on the
3rd July 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
KNAGGS, of No. 5, Euston Grove, Euston Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of January, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Walter Knaggs, Her special licence that I, the said Walter Knaggs, my
executors, administrators, and assigns, or such others as I, the said Walter
Knaggs, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term berein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR

page_text: EVAPORATING AND BOLLING SACCHARINE LIQUORS," upon the condition (amongst
others) that I, the said Walter Knaggs, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Walter Knaggs, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
Heretofore from time to time various endeavours have been made having
for their object the rapid evaporation of solutions by running them in thin
continuous films over beated surfaces either in the form of plates or trays, but
the objection to this is that there is great risk of deterioration by the liquors
becoming dry and carbonized. My object is to construct such an evaporator
as will secure the juice or liquor operated upon from such risks by ensuring
at all times such a covering of the heated surfaces over which the liquor is
passed that while the depth of liquor will not offer any impediments to the
boiling process, as would be the case if it was too deep, a covering of all the
heated surfaces shall still at all times be secured.
In the Drawing hereunto annexed is shewn a longitudinal and transverse
section of an apparatus suitable for thus evaporating and boiling saccharine-
liquids. The evaporating tray is in the arrangement shewn heated by steam,.
but it might be otherwise beated.
a is the evaporating tray, which is by preference of copper, and is formed
with an even flat surface; this tray is fixed at a slight inclination so as to
slope downward from one of its ends towards the opposite end; I prefer that
the tray should be set with a fall of about 1 inch in 18 feet, but this may be
varied; the dimensions may also be greatly varied; a convenient size is
about 18 feet in length by 6 feet in width. b is a steam boiler below the
tray a; projecting downwards from the bottom of this boiler are a number
of small tubes b¹ to increase the surface exposed to the action of the fire by
which the boiler is heated; each of these tubes communicates at its upper
end with the boiler, and dipping down into each of them is a smaller tube to
facilitate the circulation of the water, as is well understood; by this means a
very free supply of steam is generated for heating the evaporating tray a.

page_text: c, c, are a number of tubes placed transversely across the evaporating tray a;
these tubes at their ends open into the steam space of the boiler below; I
prefer that these tubes should be of about 1 to 2 inches in diameter, and
they should be placed about half an inch above the surface of the tray, so
that if a stream of about 1 inch in depth more or less is supplied on to the
surface of the tray it may as it bubbles up cover.over the tubes, or the tubes
may at some times be covered by the liquor. By thus applying a number of
heated tubes above the surface of the tray the evaporating power of the
apparatus will be considerably increased. The saccharine liquor to be boiled
or evaporated is supplied to the upper end of the tray by a pipe d furnished
with a suitable cock or valve for regulating the flow of liquor, and the liquor
flows in a straight course down the tray, and ultimately passes off from its
lower end in a concentrated state of more or less density according to the
speed of flow, the length of the tray, and the heat applied. A saccharometer
is fitted in the channel into which the liquor is received as it passes from the
evaporating tray, so that its density may be seen and the flow of liquor over
the tray may be regulated accordingly. In place of heating the tray by
steam as above described it may be heated by means of steam from a separate
boiler or heated directly by a fire; in this latter case the transverse tubes
will be of course omitted, and knobs or projections, solid or hollow, may be
formed to project downwards from the under side of the tray so as to offer a
greater heating surface to the action of the fire, and communicate the heat so
taken up to the boiling liquor; rims projecting up from the tray are also
placed along its sides and ends to prevent the liquor escaping, and the lower
end is furnished with a shifting sluice by which the depth of the liquor may
be regulated. I prefer that the tray should be covered over with a double
cover as shewn at e, e; but this is not essential..
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that what I claim is,
the combining apparatus for evaporating and boiling saccharine liquors in the
manner herein described, whereby the liquor is passed in a continuous stream
and in a straight course over the surface of a plate or tray heated either by
steam from a boiler below, as described, or otherwise, or by a fire on its under
side, the stream being of such a depth as not to offer any impediment to the
boiling process, and yet being sufficient to ensure a covering of all the heated
surfaces.
I also claim when employing steam for heating the evaporating tray or
plate of the apparatus the applying a number of tubes placed above the surface

page_text: of the tray, and communicating with the steam space below it as herein
described.
In witness whereof, I, the said Walter Knaggs, have hereunto set my
hand and seal, this Twenty-eighth day of June, in the year of our
Lord One thousand eight hundred and sixty-seven.
WALTER KNAGGS. (L.S.)