Improvements in Apparatus for Softening, Limping, or Humidifying Tobacco Leaf or other analogous Substances.
Year: 1899

page_text: Date of Application, 20th Feb., 1899
Complete Specification Left, 17th Nov., 1899-Accepted, 27th Jan.,
1900
Improvements in Apparatus for Softening, Limping, or Humidifying
Tobacco Leaf or other analogous Substances.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ire-
land, Merchant, do hereby declare the nature of this invention to be as follows:
My invention has reference to apparatus for softening, limping or humidify-
ing tobacco leaf or ether analogous substances by the application thereto of
steam, aqueous vapour, or moist air (hereinafter referred to as
the aqueous
vapour) or of a mixture of steam, air, and water, in the form of a hot mist-
like spray (hereinafter referred to as the spray); and it relates more particu-
larly to the apparatus shown and described in the Specification of previous
Letters Patent granted to me and dated 23rd June 1897 No. 15,107.
The objects of my present invention are to provide in said apparatus, improved
appliances for the application of said aqueous vapour, and also for the regula-
tion of the amount of additional water incorporated therewith in said spray, to
increase the proportion of moisture to be added to dried tobacco leaf or other
analogous substances (hereinafter referred to as the leaf) which are being treated
therein.
In the apparatus described in my previous specification the leaf just as it was
entering the feed end, was first subjected to said hot mist-like spray of steam
and water, which was produced by projecting jets of steam through correspond-
ing jets of water passing accurately in front of said steam jets, and subse-
quently in order to keep up the heat of the layer of leaf while travelling through
said apparatus, it was further subjected to additional jets of steam, and the
vapour produced thereby was guided in an alternating downward and upward
current, by suitably arranged partitions above and below the layer of leaf, and
drawn through same by a fan operating partly by suction draft at the discharge
end of the apparatus, and partly by returning a portion of the current under
pressure at the feed end: but in practice I have ascertained that better
results can be obtained by firstly subjecting the leaf to a current of
aqueous vapour consisting of steam and air only, in order to slightly humidify
and warm it throughout, whereby its tendency to absorb further moisture
rapidly is greatly increased, and then subsequently to apply the further mois--
ture required by means of the spray: and that as it is important to get the
leaf heated up as rapidly as possible. immediately on its entering the apparatus,
and as the introduction of any of the return current from the fan as a pressure
blast at the feed end, reduces the initiatory heat communicated to the leaf by
the steam jets, I now accordingly employ the fan to produce only a suction
current of the aqueous vapour from the feed to the discharge ends of the appa-
ratus, and no part of the return or pressure current from the fan is now intro-
duced at the feed end. I have further found that in the arrangement shown and
described in my previous specification for producing the spray, it was difficult to

page_text: regulate and adjust the proportion of water added thereto, and also to ensure
that each water jet was entirely absorbed and atomised by cach steam jet, for
when the water jet was stronger or weaker, according as the spray was required
to be more or less charged with water, and if it did not pass quite accurately
in front of the steam jet, some of the water was liable to fall past it, and not
be absorbed into the spray, which thus caused inequality in the distribution of
the additional water being added to the leaf. Then again a difficulty which
attended the introduction of said sprays, excepting at where the leaf was just
entering the apparatus, was the necessity that the water jets should be visible
to the attendant, and therefore outside the apparatus, to enable him to judge of
the quantity of water being added to the spray, and that the spray jets, when
so placed as to operate on the leaf after it had been carried inside the body of
the apparatus, should enter the apparatus from outside through as small orifices
in the casing as practicable, so that the induced current of air carried in with
them should be as small as possible, in order to minimize the cooling effects of
the air on the leaf, whereby its tendency to absorb the moist spray into the thick
parts of its tied up bunches and into the hearts of its stems, would be diminished.
Now, my present invention consists firstly in applying to the leaf just as it
is entering the apparatus, a series of steam jets at the opening through which
the leaf is admitted, and which is made just sufficiently large to allow of said
sprays passing freely over the leaf and into the apparatus, together with a suit-
able volume of air current to act as a carrier and distributor of the steam vapour
through the leaf, and which current is produced by the combined operation of
induction by said steam jets and the suction of the fan from the opposite end
of the apparatus; and after the leaf has passed inside the apparatus, in applying
other series of steam jets to operate thereon, alternately on the top and bottom
of the layer of leaf travelling through, whereby it is heated to the heart, and
also to a certain extent humidified, in which condition it will then absorb with
avidity the sprays of steam, in combination with the required amount of addi-
tional water which are then applied as follows:-
On the top and outside of the apparatus, and in the position where it has
been ascertained that the leaf is usually sufficiently heated and humidified to
rapidly and advantageously absorb said sprays, a trough-shaped appliance is
mounted, transversely to the travel of the layer of leaf, over which trough the
requisite number of steam jets are adjusted, with their points downwards, and in
front of each jet said trough has hopper-shaped sub-divisions, with an orifice
in the bottom of each hopper and of suitable size to freely allow the jet of
steam to pass through same into a downward continuation pipe therefrom pass-
ing through the top cover of the apparatus into the space within same and
above the layer of leaf. Alongside each of said steam jets there is a water nozzle
from which a regulated stream of water falls into each hopper and flows down
into said continuation pipe, and the steam in passing through said pipe
thoroughly combines with the water, which is also flowing down through same,
and produces therewith a mist-like spray from the down end of the pipe over
the leaf, in a perfectly even manner.
The water jets are arranged to fall from a few inches above the trough, so as
to be clearly visible to the attendant, in order that he can see that all the
nozzles are acting, which is of importance owing to their being of very small
diameter, and consequently liable to get choked with small obstructions which
may be carried in the water. In order that the amount of water passing
through the jets may be accurately regulated, so as to ensure equality in the
amount of moisture added to the leaf when discharged from the apparatus, with-
out depending on the judgment of the attendant in regard to the quantity of
water flowing out of the nozzles, which heretofore in practice has been a
matter of guesswork, based on the visible force and strength of the jets I
employ on the reservoir pipe from which said water nozzles are led, and which
I make of larger diameter than the supply, pipe thereto, a vertical gauge glass,

page_text: open at the top to the atmosphere, and marked with a scale, so that when the
pressure within the reservoir pipe rises to any particular mark on said gauge
glass, the quantity of water passing through each nozzle will always be the
same. A few trial experiments will enable the attendant to ascertain exactly
what head of water in said gauge glass gives the requisite amount of additional
moisture which it may be necessary to incorporate with the steam, in order to
have the leaf moistened to just the extent that is required by the Excise autho-
rities who supervise such work in tobacco factories; and by having said vertical
gauge glass open at the top, it allows of the escape of any confined air there
may be in the reservoir pipe from which the jets are taken, so that any in-
equality of flow from the nozzles, due to confined air, is thus obviated.
11:00T
1. of Wahmom. 1900
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents.
Improvements in Apparatus for Softening, Limping, or Humidifying
Tobacco Leaf or other analogous Substances.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ire-
land, Merchant, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :—
My invention has reference to apparatus for softening, limping or humidify-
ing tobacco leaf or other analogous substances by the application thereto of
steam, aqueous vapour, or moist air (hereinafter referred to as
the aqueous
vapour) or of a mixture of steam, air, and water, in the form of a hot mist-
like spray (hereinafter referred to as the spray); and it relates more particu-
larly to the apparatus shown and described in the Specification of previous
Letters Patent granted to me and dated 23rd June 1897 No. 15,107.
The objects of my present invention are to provide in said apparatus, improved
appliances for the application of said aqueous vapour, and also for the regula-
tion of the amount of additional water incorporated therewith in said spray, to
increase the proportion of moisture to be added to dried tobacco leaf or other
analogous substances (hereinafter referred to as the leaf) which are being treated
therein.
In the apparatus described in my previous specification the leaf just as it was
entering the feed end, was first subjected to said hot mist-like spray of steam
and water, which was produced by projecting jets of steam through correspond-
ing jets of water passing accurately in front of said steam jets, and subɛe-
quently in order to keep up the heat of the layer of leaf while travelling through
said apparatus, it was further subjected to additional jets of steam, and the
vapour produced thereby was guided in an alternating downward and upward
current, by suitably arranged partitions above and below the layer of leaf, and
drawn through same by a fan operating partly by suction draft at the discharge
end of the apparatus, and partly by returning a portion of the current under
pressure at the feed end but in practice I have ascertained that better
results can be obtained by firstly subjecting the leaf to a current of
aqueous vapour consisting of steam and air only, in order to slightly humidify

page_text: and warm it throughout, whereby its tendency to absorb further moisture
rapidly is greatly increased, and then subsequently to apply the further mois-
ture required by means of the spray; and that as it is important to get the
leaf heated up as rapidly as possible, immediately on its entering the apparatus,
and as the introduction of any of the return current from the fan as a pressure
blast at the feed end, reduces the initiatory heat communicated to the leaf by
the steam jets, I now accordingly employ the fan to produce only a suction
current of the aqueous vapour from the feed to the discharge ends of the appa-
ratus, and no part of the return or pressure current from the fan, is now intro-
duced at the feed end. I have further found that in the arrangement shown and
described in my previous specification for producing the spray, it was difficult to
regulate and adjust the proportion of water added thereto, and also to ensure
that each water jet was entirely absorbed and atomised by each steam jet, for
when the water jet was stronger or weaker, according as the spray was required
to be more or less charged with water, and if it did not pass quite accurately
in front of the steam jet, some of the water was liable to fall past it, and not
be absorbed into the spray, which thus caused inequality in the distribution of
the additional water being added to the leaf. Then again a difficulty which
attended the introduction of said sprays, excepting at where the leaf was just
entering the apparatus, was the necessity that the water jets should be visible
to the attendant, and therefore outside the apparatus, to enable him to judge of
the quantity of water being added to the spray, and that the spray jets, when
so placed as to operate on the leaf after it had been carried inside the body of
the apparatus, should enter the apparatus from outside through as small orifices
in the casing as practicable, so that the induced current of air carried in with
them should be as small as possible, in order to minimize the cooling effects of
the air on the leaf, whereby its tendency to absorb the moist spray into the thick
parts of its tied up bunches and into the hearts of its stems, would be diminished
Now, my present invention consists firstly in applying to the leaf just as it
is entering the apparatus, a series of steam jets at the opening through which
the leaf is admitted, and which is made just sufficiently large to allow of said
sprays passing freely over the leaf and into the apparatus, together with a suit-
able volume of air current to act as a carrier and distributor of the steam vapour
through the leaf, and which current is produced by the combined operation of
induction by said steam jets and the suction of the fan from the opposite end
of the apparatus; and after the leaf has passed inside the apparatus, in applying
other series of steam jets to operate thereon, alternately on the top and bottom
of the layer of leaf travelling through, whereby it is heated to the heart, and
also to a certain extent humidified, in which condition it will then absorb with
avidity the sprays of steam, in combination with the required amount of addi-
tional water which are then applied as follows:-
On the top and outside of the apparatus, and in the position where it has
been ascertained that the leaf is usually sufficiently heated and humidified to
rapidly and advantageously absorb said sprays, a trough-shaped appliance is
mounted, transversely to the travel of the layer of leaf, over which trough the
requisite number of steam jets are adjusted, with their points downwards, and in
front of each jet said trough has hopper-shaped sub-divisions, with an orifice
in the bottom of each hopper and of suitable size to freely allow the jet of
steam to pass through saame into a downward continuation pipe therefrom pass-
ing through the top cover of the apparatus into the space within same and
above the layer of leaf. Alongside each of said steam jets there is a water nozzle
from which a regulated stream of water falls into each hopper and flows down
into said continuation pipe, and the steam in passing through said pipe
thoroughly combines with the water, which is also flowing down through same,
and produces therewith a mist-like spray from the down end of the pipe over
the leaf, in a perfectly even manner.
The water jets are arranged to fall from a few inches above the trough, so as

page_text: to be clearly visible to the attendant, in order that he can see that all the
nozzles are acting, which is of importance owing to their being of very small
diameter; and consequently liable to get choked with small obstructions which
may be carried in the water. In order that the amount of water passing
through the jets may be accurately regulated, so as to ensure equality in the
amount of moisture added to the leaf when discharged from the apparatus, with-
out depending on the judgment of the attendant in regard to the quantity of
water Howing out of the nozzles, which heretofore in practice has been a
matter of guesswork, based on the visible force and strength of the jets I
employ on the reservoir pipe from which said water nozzles are led, and which
I make of larger diameter than the supply pipe thereto, a vertical gauge glass,
open at the top to the atmosphere, and marked with a scale, so that when the
pressure within the reservoir pipe rises to any particular mark on said gauge
glass, the quantity of water passing through each nozzle will always be the
same. A few trial experiments will enable the attendant to ascertain exactly
what head of water in said gauge glass gives the requisite amount of additional
moisture which it may be necessary to incorporate with the steam, in order to
have the leaf moistened to just the extent that is required by the Excise autho-
rities who supervise such work in tobacco factories; and by having said vertical
gauge glass open at the top, it allows of the escape of any confined air there
may be in the reservoir pipe from which the jets are taken, so that any in-
equality of flow from the nozzles, due to confined air, is thus óbviated.
Figure 1 of the accompanying drawings is a side elevation of an apparatus
in which my present invention is embodied.
Figure 2 is an end elevation of the feed end of the apparatus.
Figure 3 is a plan of the apparatus.
A represents the woven wire endless web carried upon the two revolving
drums B B, and supported between same by rollers C, D is the moistening or
softening chamber through which the upper portion of the wire web-A travels
in the direction indicated by the arrow. The said chamber is divided into upper
and lower compartments by the web A, and these are further divided into sub-
compartments DEFGHJK and L by the cross partitions D'E' FIGH¹
and J respectively.
M and M are the openings into the ends of the chamber for the entrance
and exit respectively of the wire web.
Upon the chamber is mounted the fan N producing a suction current of the
aqueous vapour from the feed to the discharge ends of the apparatus, the air is
drawn from the machine up through the air ducts 00' to the fan N. The ducts
are shown as close to the delivery end but they may in some instances be located
at or near the centre of the machine in which latter case the steam jets s may
also be placed above and below the webs near to the delivery end when it is
desired that the material delivered from the machine should come out hot. In
this latter case an induced current of air is drawn through the opening, at the
discharge end as well as at the feed end, and mixing with steam is caused to
pass up and down through the material on the web in the opposite direction to
the movement of the material, till it eventually reaches the exhaust duct to
the fan, which as already mentioned in this case would be near the centre of
the apparatus and simultaneously exhaust from both ends thereof, the exhaust
air being discharged into the atmosphere through the exhaust pipe P.
The bearings Q of the shaft carrying the drum B at the feed end of the
machine, are fitted with adjusting screws Q so that the web may be kept just
sufficiently tightly strained for satisfactory working.
The working of the apparatus is as follows:-
As the material spread upon the web A enters the upper sub-compartment D
by the entrance port M, it is moistened and heated by jets of steam from the
pipe R (supplied from any convenient source) the steam being carried and dis-
tributed by a suitable volume of air current, which is produced by the com-

page_text: bined inductive action of the steam jets, and the suction of the fan N. When
the material has passed inside the apparatus, it is further operated on by the
jets of steam from the pipes S, S1, S2 and S³, placed alternately above and
below the layer of leaf passing through. On the top and outside of the appa-
ratus, a trough-shaped appliance T is mounted transversely to the travel of the
leaf. The trough T is divided into hopper-shaped sub-divisions T with an
orifice at the bottom of each, and over each sub-division are steam jets and
water nozzles supplied from steam and water pipes UV respectively. The
water falls by gravitation into the trough, and descends into the pipe W, while
the jets of steam are also directed through same, and cause an induced current
of air therewith through the pipe W, from which the combination of water,
steam and air is projected in the form of a mist-like spray on to the surface of
the material passing below it on the web. A vertical gauge glass X is placed
on the main water pipe V, in order to indicate the quantity of water passing
through the nozzles, which quantity will be constant for a given height of water
in the gauge glass.
The material is discharged from the apparatus by the exit port M', and falls
from the web A into the truck Y placed in position to receive it. 7 is the
rotary brush for removing any material clinging to the wire web A. 22 are
inspection and cleaning doors. The web A can be driven by ineans of the
drum B at the delivery end, by any suitable gear; that shown is an arrange-
ment of worm gearing 3, 4, 5 and 6 operated by the driving pulley 7.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In apparatus of the type herein before referred to, for moistening, limp-
ing, or humidifying tobacco leaf or other analogous substances, the employment
of a series of hopper-shaped troughs with an orifice in the bottom of each, and
a downwardly directed continuation pipe or nozzle therefrom into each of which
troughs a jet of steam and also a jet of water are directed so as to pass together
down through said continuation pipe or nozzle, in order to ensure a perfectly
complete absorption of the water by the steam, whereby a finely atomised or
mist-like spray is formed and projected from said continuation pipe over the
layer of leaf or substance passing through said apparatus all substantially as
herein before described.
2. In apparatus of the type hereinbefore referred to, for moistening, limping,
or humidifying tobacco leaf or other analogous substances, in which steam and
water jets are employed as set forth in Claim 1, the combination with the reser-
voir pipe from which said water jets are supplied of a transparent stand pipe,
or gauge glass, communicating at its lower end with said reservoir pipe, and
at its other end with the atmosphere and provided or marked with a suitably
graduated scale, whereby the head of water operating as pressure on the said
water jets is visible, so that by adjustment of said head or pressure, the quan-
tity of water flowing through said jets can be accurately regulated, all sub-
stantially as herein before described.
3. The combination of parts substantially as herein before described with
reference to the accompanying drawings constituting an improved apparatus
for softening, limping, or humidifying tobacco leaf or other analogous sub-
stances.
Dated this 17th 1 of Nawahan 1800
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents.