AN IMPROVED PROCESS OR METHOD OF DRYING STARCH AND OTHER AMYLACEOUS SUBSTANCES
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine Lake
& Co, Patent Agents, Southampton Buildings London for an Invention of
<E
'AN IMPROVED PROCESS OR METHOD OF DRYING STARCH AND OTHER
AMYLACEOUS SUBSTANCES
Maiche, of Paris, France.
"
Communicated to him from abroad by Louis
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 28th December 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine Lake and Co. Patent Agents,
Southampton Buildings, London, "AN IMPROVED PROCESS OR METHOD OF
DRYING STARCH AND OTHER AMYLACEOUS SUBSTANCES." [A communication to
him from abroad by Louis Maiche, of Paris, France.]
This invention relates to an improved process of rapidly drying starch and other
amylaceous substances in vacuo by which process I am enabled to effect this
operation in a very short time and at a temperature lower than twenty-five
degrees; as evaporation takes place at a very low pressure, heating surfaces of
considerable extent can be employed, the heat from which accelerates, in a large
degree, the drying of the starch without the temperature being at any time raised
above that corresponding to the point of ebullition of water under this low pressure;
the crystallization of the starch can also be effected in about twelve hours in very
favourable condition from the double point of view of the uniformity and the
quality of the product obtained.
The advantages resulting from the employment of this process are as follow, that
is to say-It avoids the loss of material arising from fermentation and rot or
mildew which frequently take place in the centre of blocks of starch during the
long period of drying in the ordinary stoves; moreover inferior qualities of starch
which will not keep during the twenty days which the ordinary drying process
requires, may be treated without any inconvenience by the said improved process ;i

page_text: and the short duration of the operation enables me to effect great economy in the
use of the material actually necessary for this operation, as well as in regard to the
capital employed and rendered inactive by the necessity for keeping the daily
production of the manufactory for a period of about twenty days; and further-
more, as above stated, the quality of the starch obtained is (other things being
equal) superior to that produced by the ordinary method of drying by means of a
stove; the crystals being of great uniformity and any injury arising from mildew
or from lactic, alcoholic, or other fermentation, not being liable to occur during the
short period required for the operation.
L
This process of rapid drying in vacuo can be applied with equal advantages not
only to starch obtained from wheat, rice, maize and other cereals, but also to all
amylaceous substances, especially those the drying of which should be effected at a
low temperature and with many precautions.
The improved process is carried into practice in the following simple manner,
that is to say-The blocks of drained starch or raw starch are first dried by a
stove, in the usual manner, for a sufficient length of time to form a thin yellow
layer upon their surface, which layer must then be detached from them; the
duration of this operation is about twenty four hours; this layer being removed
the blocks which still contain a proportion of about eighteen per cent of water are
wrapped in paper and subjected to the double action of a vacuum and heat in a
closed apparatus.
This apparatus is so arranged as to be capable on the one hand, of being heated
by steam by means of a double casing or of an internal serpentine pipe, and on the
other hand, of being subjected to a very energetic exhaust obtained by means of
powerful air pumps or other apparatus capable of maintaining a good vacuum,.such
as a water blowing engine or an ejector.
I can dispense with placing the starch in a stove for twenty-four hours by
directly placing the blocks of raw starch (having twenty five per cent. of water
and previously wrapped in paper) in receptacles subjected to the combined action
of a vacuum and heat; this process necessitates a greater expenditure of fuel for
effecting the drying but it prevents the waste resulting from the formation of the
yellow layer which covers the starch when it is subjected in a drying stove to an
active evaporation determined only by the action of heat.
In all cases it is important that the temperature and pressure should be as
constant as possible in the apparatus, and for this purpose the latter should be
provided with means for easily regulating and controlling the temperature and
pressure.
I attain this result by fitting to the apparatus a manometer or vacuum gauge,
and a thermometer arranged in such a manner that the indications of temperature
may be easily seen from the exterior; morever valves or cocks should be provided
for regulating the quantity of steam introduced into the double casing or serpentine
pipe for heating purposes; this result is attained in the most favourable form and
independently of the care of the operatives, by the employment of a pressure
regulator acting automatically upon the cock for the admission of steam to the
beating surfaces.
In order that the external air may not accidentally enter the apparatus, in cases
where the air pumps or other apparatus for creating a vacuum should from any
cause cease to operate, their communication pipe is furnished with a retaining valve
arranged for this purpose.
According to one arrangement the apparatus consists of a vertical cylindrical
receptacle of strong sheet metal provided with shelves upon which the blocks of
starch are deposited, the said blocks being introduced through a manhole at the
top; the heating of the apparatus is effected by means of a serpentine pipe provided
at its extremities with regulating cocks; a suitable pipe is provided communicating
with the air pump and having a regulating cock and an internal valve for
preventing the entrance of air into the apparatus through the said pipe. The

page_text: said serpentine pipe may, if desired, be replaced by a simple vertical pipe beut one
or more times.
According to another arrangement the apparatus consists of a vertical cylindrical
vessel closed at its upper part by a cover of the same diameter permitting the
introduction of a series of shelves upon which the starch to be dried is deposited
and which are operated by means of a crane or pulleys. The apparatus is provided
with interior serpentine or bent pipes and has the above described pipes, valves,
and cocks for putting it in communication with the apparatus for creating a
vacuum.
It is obvious, however, that the form and arrangement of the apparatus designed
to receive the blocks of starch to be dried can be modified in many ways.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
23rd June 1883.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, London, AN IMPROVED PROCESS OR METHOD OF
DRYING STARCH AND OTHER AMYLACEOUS SUBSTANCES A communication to
me from abroad by Louis Maiche, of Paris, France.
"
This invention relates to an improved process or method of rapidly drying starch
and other amylaceous substances in vacuo, by which process I am enabled to effect
this operation in a very short period of time and at a temperature below twenty-
five degrees Centigrade; as evaporation takes place at a low pressure, heating
surfaces of considerable extent can be employed, the heat from which greatly
accelerates the drying of the starch, without the temperature being at any time
raised above that corresponding to the boiling point of water under this low
pressure; the crystallization of the starch can thus be effected in about twelve hours
under very favorable conditions from the double point of view of the uniformity
and the quality of the product obtained.
The advantages resulting from the employment of this process are as follow, that
is to say; It avoids the loss of material arising from fermentation and rot or
mildew which frequently take place in the centre of blocks of starch during the
long period of drying in the ordinary stoves; moreover inferior qualities of starch,
which will not keep during the twenty days which the ordinary drying process
requires, may be treated without any inconvenience by the said improved process;
and the short duration of the operation enables me to effect great economy in the
use of the material actually necessary for this operation, as well as in regard to the
capital employed and rendered inactive by the necessity for keeping the daily
production of the manufactory for a period of about twenty days; and furthermore,
as above stated, the quality of the starch obtained is (other things being equal)
superior to that produced by the ordinary method of drying by means of a stove,
the crystals being of great uniformity, and any injury arising from mildew or from
lactic, alcoholic or other fermentation, not being liable to occur during the short
period required for the operation.
This process of rapid drying in vacuo can be applied with equal advantages not
only to starch obtained from wheat, rice, maize and other cereals, but also to all
amylaceous substances, the drying of which should be effected at a low temperature
and with great care.
The improved process is carried into practice in the following simple manner,
that is to say-The blocks of drained starch or raw starch are first dried in a
stove in the usual manner, for a sufficient length of time to allow a thin yellow
layer to form upon their surface, which layer must then be detached from them!; the
duration of this operation is about twenty-four hours; this layer being removed,
the blocks, which still contain a proportion of about eighteen per cent of water, are
wrapped in paper and subjected to the double action of a vacuum and heat in a
closed apparatus.
This apparatus is so arranged as to be capable, on the one hand, of being heated
by steam by means of a double casing or of an internal serpentine pipe, and, on the
other hand, of being subjected to a very energetic exhaust obtained by means of

page_text: powerful air pumps or other apparatus capable of maintaining a good vacuum, such
as a water blowing engine or an ejector.
I can dispense with placing the starch in a stove for twenty-four hours by
directly placing the blocks of raw starch (having twenty-five per cent of water
and previously wrapped, in paper) in receptacles subjected to the combined action
of a vacuum and heat; this process necessitates a greater expenditure of fuel for
effecting the drying, but it prevents the waste resulting from the formation of the
yellow layer which covers the starch when it is subjected in a drying stove to an
active evaporation caused by the action of heat alone.
In all cases, it is important that the temperature and pressure should be as
constant as possible in the apparatus, and for this purpose the latter should be
provided with means for easily regulating and controlling the temperature and
pressure.
I attain this result by fitting to the apparatus a manometer or vacuum-gauge,
and a thermometer arranged in such a manner that the indications of temperature
may be easily seen from the exterior; moreover, valves or cocks should be provided
for regulating the quantity of steam introduced into the double casing or serpentine
pipe for heating purposes; this result is attained in the most favorable form and
independently of the care of the operatives, by the employment of a pressure
regulator acting automatically upon the cock for the admission of steam to the
heating surfaces.
In order that the external air may not accidentally enter the apparatus, in cases
where the air-pumps or other apparatus for creating a vacuum should, from any
cause, cease to operate, their communication pipe is furnished with a retaining valve
suitably arranged for this purpose.
I bave shown in the accompanying drawing, by way of example, two arrange-
ments of apparatus which I can employ with advantage in carrying on the said
process.
According to the arrangement shown in Figure 1, the apparatus consists of a
vertical cylindrical receptacle A of strong sheet-metal, provided with shelves B upon
which the blocks of starch are deposited, the said blocks being introduced through
a man-hole C; the heating of the apparatus is effected by means of a serpentine
pipe D provided at its extremities E with regulating cocks; a pipe F communicates
with the air-pump and is provided with a regulating cock and an internal valve for
preventing the entrance of air into the apparatus through the said pipe. The said
serpentine pipe D may, if desired, be replaced by a simple vertical pipe G bent one
or more times as shown in dotted lines in the drawing.
According to another arrangement, shown in Figure 2, the apparatus consists of
a vertical cylindrical vessel H, closed at its upper part by a cover I of the same
diameter, permitting the introduction of a series of shelves K placed one above
another upon which the blocks of starch to be dried are deposited and which are
operated by means of a crane or pulleys. The apparatus is provided with interior
serpentine steam pipes L and has the pipes, valves and cocks designed for putting
it in communication with the apparatus for creating a vacuum.
It is obvious, however, that the form and arrangement of the apparatus designed
to receive the block of starch to be dried can be modified in many ways.
The above described process necessitates the employment of as perfect a vacuum
as can be obtained in order to prevent the temperature within the apparatus from
rising above about twenty or twenty five degrees centigrade, and the employment
for the same purpose of means for ensuring the uniformity of the temperature
during the whole of the drying operation.
Having thus fully described the said Invention as communicated to me by my
foreign Correspondent, and the manner of performing the same, I wish it understood
that I claim
The process of rapidly drying starch and other amylaceous substances in vacuo,
which process is based upon the combination, under the peculiar conditions above

page_text: described, of the action of a vacuum and that of heat in order to effect an active
evaporation, at a low pressure, of the liquid contained in the said substances and
thus obtain in a few hours a regular crystallization, substantially as above
Bet forth.
In witness whereof, I the said William Robert Lake, have hereunto set my
hand and seal this twenty third day of June, in the year of our Lord One
thousand eight hundred and eighty three.