An Improved Process and. Apparatus for the Treatment of Tea...
Year: 1892

page_text: Date of Application, 10th Sept., 1892.
Complete Specification Left, 10th June, 1993-Accepted, 2nd Sept:, 1893
PROVISIONAL DIEUTICALOA.
An Improved Process and. Apparatus for the Treatment of Tea...
I, HENRY CARUS-WILSON of 22 Fenchurch Street in the City of London,
Merchant, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved process and apparatus for the treatment
of tea.
It is well-known that bi-carbonate of soda has been frequently employed in the
course of the preparation of infusions of tea for use as a beverage with. the object
of iinproving the character of the infusion. The treatment of tea in this manner
is crude and unsatisfactory, inasmuch as although it is directed, to the obtainment
of increased colour, in the infusion it inevitably results in spoiling the flavour
thereof, for the reason that a mere mechanical admixture of the bicarbonate of soda
with the tea takes place, and, further, the quantity of bi-carbonate of soda used on
such occasions is seldom exactly proportioned to the quantity of the beverage desired,
and moreover is not brought properly and uniformly into contact with the whole of
the contents of the vessel in which the infusion is prepared. The necessity for the
impregnation of tea at the time the infusion is prepared is avoided by the prior
treatment of the tea by a process hereinafter described as a part of my invention
and which effects the treatment of tea leaves in such a manner that body and colour
are developed in the infusion without injury to the flavour thereof. The said
process includes carefully-regulated chemical treatment of the leaf with a mixture,
in solution, of bi-carbonate of soda and phosphate of soda, in such a manner that in
a quantity of the leaf the, action of the said solution is uniform and the quantity
thereof exactly regulated, and the proper completion of the oxidation of the tannin
is ensured.
I, perform the said treatment without subjecting the leaf to the operation of
boiling, the result being that inferior qualities of the leaf treated by the said
process are rendered as marketable as superior qualities of tea which are not so
treated. Moreover the use of bi-carbonate of soda and phosphate of soda in'
conjunction, which is a very important feature of my invention, enables the said
treatment of the tea to be effected without any such injurious discolouration of the
leaf as would occur if bi-carbonate of soda were alone employed.
.1
My said improved process comprises the impregnation of the tea, which advan-
tageously is warmed beforehand to a temperature of say 150° to 175° Fahrenheit,
with a solution of bi-carbonate of soda and phosphate of soda mixed together in the
proportion of two parts or thereabouts by weight, of the former to one part, by
weight, of the latter, the said proportions being the relative weights of the said two
substances before solution, and includes other treatment of the tea 'as hereinafter
set forth. A quantity of the said solution containing a quantity of the aforesaid
alkalies corresponding in weight to 1 to 2 per centum of the weight of the tea
treated is raised to its boiling point, and is applied to the tea in the form of fine
spray. The exact proportion of the alkalies in the said solution to the weight of
the tea depends upon the nature of the tea and the extent to which the treatment
thereof is to proceed.
5.
The tea to be treated is evenly spread by hand or otherwise, upon a band or
traveller which is caused to travel at a suitable speed beneath a series of jets
arranged to deliver the hot solution upon the tea in the form of a fine spray. The
tea thus moistened is delivered into a steam-jacketed stationary cylinder, the
temperature of which must be maintained at about 150° Fahrenheit; the tea is kept
in the said cylinder, for a period of from 15 to 30 minutes. In the said cylinder is

page_text: a rotary stirrer-shaft fitted with stirrers so arranged that as the said stirrer-shaft is
rotated, the tea in the cylinder is stirred and turned over so as to be thoroughly
mixed, and so that the whole of the contents of the cylinder may be uniformly
saturated with the solution, and at the same time the tea is steadily propelled
through the cylinder by the stirrers and finally discharged therefrom on to trays
with perforated bottoms, upon which it is spread from one to two inches deep and
allowed to remain for about twelve hours, in order that the air may have free
access thereto. I have discovered, by careful research, that it is very important
the periods occupied by the performance of the several operations as hereinbefore
set forth should not be diminished to any considerable extent, or inferior results
would be obtained.
The damp leaf is then removed from the said trays and is dried in a suitable tea-
kiln by means of a steady current of hot air passed through the tea at a temperature
of say 120° to 130° Fahrenheit; if a rotary drying-machine be employed instead of
a tea-kiln a temperature about twenty to thirty degrees higher may be employed,
without injury to the tea.
The apparatus which I employ for carrying out the aforesaid process is preferably
arranged as follows ;-
A suitable hopper is provided into which the tea for treatment previously warmed
or otherwise, is delivered. An endless elevator is arranged to take the tea from
the hopper and deliver it to a "shaker" or distributor which consists of a plate to
which a suitable movement is imparted by toggles operated by a connecting-rod.
The said "shaker" or distributor delivers the tea on to an endless band, above
which a series of nozzles or a perforated pipe is provided through which the hot
solution is pumped or otherwise delivered on to discs or plates which break it up
into a very fine spray, in which condition it falls upon the tea on the band. The
band delivers the tea to a jacketed cylinder in which stirrers rotate as aforesaid.
The said cylinder is lined with earthenware segments secured in place by counter-
sunk bolts, or other suitable means, and arrangements are made whereby when
countersunk bolts are employed the heads of the said bolts may be easily got at
when necessary. The elevator the "shaker," the pump when a pump is. employed,
the endless band, and the stirrers, are all geared together by gearing so arranged
that the speed of any of the said moving parts may be varied as may be
necessary. I wish it to be clearly understood that I do not limit myself to
the employment of the particular mechanism herein before set forth by way of
example.
By the present invention I provide a process which taking place subsequent to
the ordinary treatment to which the tea is now subjected in tea-growing countries.
completes its manufacture and enhances its value to the consumer by enabling the
body and richness of the tea to be more completely utilized, and its colour to be
better developed, and by preventing the presence in an infusion, of any undesirable
percentage of free tannin, which in excess is most injurious to the digestive organs
and the nervous system.
I may also use instead of the above named mixture of alkalies, borax, in which
case about 2 per centum by weight of borax is the best proportion to apply to the
tea, and with this the most successful results are obtained with tea of China
growth.
Dated Th 1
"

page_text: COMPLETE SPECIFICATION.
:
An Improved Process and Apparatus for the Treatment of Tea..
1, HENRY CARUS-WILSON, of 22 Fenchurch Street, in the City and County of
London, Merchant, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
My invention relates to an improved process and improved apparatus for the
treatment of tea.
:
It is well-known that in the course of the preparation of infusions of tea for use
as a beverage, bicarbonate of soda has been frequently employed with the object of
improving the character of the infusion. The treatment of tea in this manner is
crude and unsatisfactory, inasmuch as although the said treatment is directed to the
obtainment of increased colour in the infusion, it inevitably results in spoiling the
flavour thereof, for the reason among others that the bi-carbonate of soda is merely
mixed mechanically with the tea and the soda imparts to it its own characteristic
and objectionable flavour; further, the quantity of bi-carbonate of soda used on
such occasions is seldom exactly proportioned to the quantity of the beverage
desired, and, moreover, is not brought properly and uniformly into contact with the
whole of the contents of the vessel in which the infusion is prepared. The necessity
for such impregnation of tea at the time when the infusion is prepared is avoided
by the prior treatment of the tea by an improved process which is hereinafter
described as a part of my invention and which includes carefully-regulated chemical
treatment of the tea with a solution of bicarbonate of soda and phosphate of soda,
in such a manner that body and colour can afterwards be developed in an infusion
without injury to the flavour thereof.
The said treatment is effected in such a manner that in a quantity of the leaf the
action of the said solution is uniform and the quantity thereet proportioned to the
result desired; consequently the proper completion of the oxidation of the tannin is
ensured, and the complete utilization of the valuable volatile oils and essences of
the tea is rendered possible.
The said process is carried into effect subsequently to the ordinary operations to
which the tea is now usually subjected in tea-growing countries, or it may be
effected during the said operations; it enables the manufacture of the tea to be
properly completed, so that the beverage can be prepared therefrom merely by
infusion in hot water without the addition of any other agent or ingredient by the
consumer. Thus the value of the tea to the consumer is enhanced, for the body
and richness of tea subjected to the said process can be more completely utilized,
and the colour of the tea can be better developed, than when leaf is employed which
has not been so treated. Moreover the said process prevents the presence in an
infusion, of any undesirable percentage of free tannin, which, in excess, is most
injurious to the digestive organs and the nervous system, and, by ensuring the
proper incorporation of the treating agents with the leaf prevents the presence of
free soda, the disagreeable flavour of which is greatly increased in any re-drying
operation.
I carry out my process without subjecting the leaf to the operation of boiling,
the result being that inferior qualities of the leaf treated by the said process are
rendered as marketable as superior qualities of tea which are not so treated.
Moreover the use of bi-carbonate of soda and phosphate of soda in conjunction,
which is a very important feature of my invention, enables the said process to be
effected without any such injurious discolouration of the leaf, as would occur if
bi-carbonate of soda were alone employed.
My said improved process comprises the impregnation of tea with a solution of
bi-carbonate of soda and phosphate of soda mixed together in the proportion of
two parts or thereabouts by weight, of the former to one part, by weight, of the

page_text: latter, the said proportions being the relative weights of the said two substances
before solution, and it includes other treatment of the tea as hereinafter set forth.
A suitable quantity of the said solution containing an amount of the aforesaid
mixture corresponding in weight to 1 to 21 per centum of the weight of the tea
proposed to be treated, is raised to its boiling point, and is applied to the tea in the
form of fine spray or otherwise. The tea, prior to the application of the said
solution thereto is, advantageously, but not necessarily, warmed to a temperature
of about 150° Fahrenheit. The exact proportion of the alkalies in the said
solution to the weight of the tea will depend upon the origin and nature of the tea
and the extent to which the treatment thereof is intended to proceed. The tea
thus moistened should be kept moist at a temperature of not less than
150° Fahrenheit or thereabouts for a period of about 30 minutes, more or less, and
afterwards allowed to remain at rest on trays of perforated metal or the like for a
period of about 12 hours, more or less, according to the porous nature of the
original tea, the object being to enable the air to have access thereto and also to
enable the solution taken up by the leaf to completely penetrate thereinto. The tea
is finally dried in a tea-kiln by means of a steady current of hot air at a temperature
of say 120° to 130° Fahrenheit, or it may be dried in a rotatory drying-machine at
a temperature about 20° or 30° lower.
I have ascertained that it is very important that the conditions of time and
temperature as hereinbefore set forth should not be materially varied or inferior
results would be obtained.
Advantageous means whereby the aforesaid improved process can be carried
into practice will now be described, by way of example. When I employ them I
proceed as follows:-
-
The tea to be treated is evenly spread by hand or otherwise, upon a band or
traveller which is caused to travel at a suitable speed beneath a series of jets
arranged to deliver the hot solution of the mixture above-mentioned upon the tea in
the form of a fine spray.
The tea thus moistened is delivered into a steam-heated cylinder, the temperature
of which should be maintained at not less than 150° Fahrenheit; the tea is kept in
the said cylinder, for a period of 30 minutes, more or less. In the said cylinder is
a rotary stirrer-shaft fitted with stirrers so arranged that as the said stirrer-shaft is
rotated, the tea in the cylinder is stirred and turned over so as to be thoroughly
mixed, and so that the whole of the contents of the cylinder may be uniformly
saturated with the solution, and, at the same time, the tea is steadily propelled
through the cylinder by the stirrers or other suitable means arranged to act as
conveyors, and is discharged therefrom on to trays and finally dried as aforesaid.
I do not however limit myself to the employment of the particular apparatus
herein before set forth by way of example.
F
The aforesaid mixture of bicarbonate of soda and phosphate of soda in the
specified proportions can be used, if desired, in the form of a mixed powder; in
such a case the said powder is sprinkled upon the leaf by any suitable means and
the tea thus sprinkled is subjected to a hot-water spray while being turned or
stirred by suitable stirrers. The said spray effects the incorporation of the alkalies
with the leaf. The use of a solution of alkalies as aforesaid, is however a more
satisfactory way of obtaining the desired result.
If in certain cases some discolouration of the infused leaf be not objected to, 'I1
use in the aforesaid solution a larger proportion of the aforesaid alkaline mixture
than is herein before set forth and I thus obtain a super-saturated product which
may be subsequently mixed, in suitable proportions, with untreated quantities of
the same or other tea.
Borax, without the addition of phosphate of soda may be used in the treatment of
tea, to obtain results analogous to those obtained by the process herein before set
forth an exact description of the said treatment of the tea with borax is set forth
in the Specification of prior Letters Patent No. 8651 granted to me and
dated 6th May, 1892.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The impregnation of tea with bicarbonate of soda and phosphate of soda,
substantially as herein before described, for the purposes specified.
2. The process of treating tea so as to effect its proper impregnation with
bicarbonate of soda and phosphate of soda, and its subsequent treatment, all
substantially as herein before described, for the purpose specified.
3. The improved product consisting of tea of an improved character produced by
the treatment of the leaf with bicarbonate of soda and phosphate of soda,
substantially as herein before described.
Dated this 10th day of June 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.