Improvements in Pneumatic Apparatus for Elevating or Conveying Tobacco Leaf, Tea Leaf, Wood or other Chips or Cuttings, or other Materials.
Year: 1897

page_text: Date of Application, 8th June, 1897
Complete Specification Left, 7th Mar., 1898-Accepted, 8th June, 1898
Improvements in Pneumatic Apparatus for Elevating or Conveying
Tobacco Leaf, Tea Leaf, Wood or other Chips or Cuttings, or other
Materials.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland,
Merchant, do hereby declare the nature of this invention to be as follows:-
My invention has reference to pneumatic apparatus for elevating or conveying
tobacco leaf, tea leaf, wood or other chips or cuttings or other materials. The
improved apparatus has been more particularly designed for elevating tobacco
leaf.
The chief features of the invention, apart from the general construction or
arrangement of the apparatus are an automatically opening and closing flap door or
valve between a feed hopper and the blast pipe for the purpose hereinafter set forth;
a special arrangement of truck or receptacle at the delivery end of the blast pipe;
and a return pipe leading from the receiving room back to the fan or air propeller,
so that the same air is used over and over again in the elevator and in the delivery
room, which is of importance when dealing with some materials, tobacco leaf for
example.
Having stated the chief features of the invention I will describe an apparatus in
which the improvements are embodied.
The apparatus consists of a duct or pipe through which a strong blast of air is
driven from a fan or other form of air propeller, a hopper being attached to the
duct at the fan end, and so constructed that when a basketful of tobacco leaf or
other material to be elevated or conveyed through the duct is thrown into same,
the leaf drops into an eddy space in the duct formed by enlarging the upper side
of the duct, the enlargement gradually converging again to the normal size of the
duct in the direction that the blast is moving. There is an inlet port or opening
from the hopper to the said eddy space, fitted with a flap door or valve, which
after a basketful of leaf or other material has fallen through the hopper doorway
or port and right into the blast current is at once automatically blown back so as
to close the inlet port by the temporary back pressure of the air blast against the
back of the flap door due to partial obstruction momentarily caused by the
material falling into the air blast and until same imparts momentum thereto.
This automatic closure of the hopper door so confines and prevents the escape of
any of the air blast, that its full pressure operates on the material thrown into the
luct until it has acquired the same velocity as the blast or been discharged at the
delivery end of the duct when the hopper door falls freely open again, and a further
supply of material may be thrown in.

page_text: In the case of some materials, tobacco leaf for example, it is in some instances
undesirable to deliver into the leaf receiving room such a large volume of fresh
air as would be continuously issuing from the delivery end of the conveyor duct
while working, if such air were drawn from another room or from the open air.
In order to obviate this I lead a return pipe from the said delivery room back to
the eye of the fan, so that the air used in the conveyor duct is practically the same
air circulating through it over and over again, owing to this air being withdrawn
from the same room or compartment as the material is being delivered into.
Hence the air in the receiving room is neither added to nor diminished, nor is the
degree of atmospheric moisture in the room altered while the conveyor is working,
which in some cases is of much practical importance.
In order to collect the leaf or other material in an open-topped box-shaped truck
or receptacle at the delivery end of the conveyor duct, I keep the delivery end at a
sufficient elevation above the ground or floor that when a downwardly directed
bend is applied thereon there is room for the truck or wagon to be placed under it,
and I apply on the top of the truck a cover of wire netting or other foraminous
material with a central hole in it of approximately the size of the mouth of the
conveyor duct, and I place the truck so that the mouth of the duct with or without
an elongation of flexible material such as canvas is fair over, and the flexible
elongation when used hanging into, the central hole in the wire netting cover.
This cover, while allowing the free escape of the air reverberating off the bottom
and sides of the truck, catches any of the leaf or material which blows upwards
along with it, and the same falls back again into the truck. The employment of
this device obviates any necessity, for what is known as a "stive" or collecting
room.
Dated this 8th day of June 1897.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.
Improvements in Pneumatic Apparatus for Elevating or Conveying
Tobacco Leaf, Tea Leaf, Wood or other Chips or Cuttings, or other
Materials.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland,
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 has reference to pneumatic apparatus for elevating or conveying
tobacco leaf, tea-leaf, wood or other chips or cuttings, or other materials.
The improved apparatus has been more particularly designed for elevating
tobacco-leaf.
The chief features of the invention, apart from the general construction or
arrangement of the apparatus, are an automatically opening and closing flap door or
valve between a feed-hopper and the blast pipe for the purpose hereinafter set forth,
a special arrangement of truck or receptacle at the delivery end of the blast-pipe,
and a return-pipe leading from the receiving room back to the fan or air propeller,
so that the same air is used over and over again in the elevator and in the delivery
room, which is of importance when dealing with some materials-tobacco leaf for
example.

page_text: Having stated the chief features of the invention, I will describe an apparatus in
which the improvements are embodied.
In the accompanying drawings, Figure 1 is a side elevation of a pneumatic
elevating apparatus constructed according to this invention. Figure 2 is a front
elevation. Figure 3 is a side elevation taken from the opposite side to that shown
in Figure 1. Figure 4 is a plan of the lower or receiving portion showing the
fan and the feed-hopper. Figure 5 is a plan of the upper or delivering portion,
illustrating the delivery into a truck. Figure 6 is a part vertical section on the
line 6-6 of Figure 4, on a larger scale than the other figures, to show the arrange-
ment of the feed-hopper door.
The apparatus consists of a duct or pipe B, through which a strong blast of air
is driven from an air-propeller, preferably in the form of a fan A, as shown, a
hopper C being attached to the duct B at the fan end and so constructed that when
a basketful of tobacco-leaf or other material to be elevated or conveyed through
the duct B is thrown into same the leaf drops into an eddy-space B₁ in the duct
formed by enlarging the upper side of the duct, the enlargement gradually con-
verging again to the normal size of the duct, as seen in Figure 6, in the direction
that the blast is moving. There is an inlet port or opening D from the hopper to
the said eddy-space B₁ fitted with a flap door or valve E, which after a basketful
or like quantity of leaf or other material has fallen through the hopper doorway or
port D and right into the blast-current is at once automatically blown back, so as
to close the inlet port, as seen in Figure 6 by the temporary back pressure of the
air-blast against the back of the flap-door E, due to partial obstruction momentarily
caused by the material falling into the air-blast and until same imparts momentum
thereto. This automatic closure of the hopper door E so confines and prevents the
escape of any of the air-blast that its full pressure operates on the material thrown
into the duct until it has acquired the same velocity as the blast or been discharged
at the delivery end of the duct, when the hopper-door freely opens again, and a
further supply of material may be thrown in.
N is a table upon which the material to be elevated may be laid, so as to be
more conveniently fed into the hopper C.
In the case of some materials-tobacco leaf for example it is in some instances
undesirable to deliver into the leaf-receiving room Q such a large volume of fresh
air as would be continuously issuing from the delivery end of the conveyer-duct B
while working if such air were drawn form another room or from the open air.
In order to obviate this, I lead a return pipe L, having an open mouth or inlet K,
from the said delivery room back to the eye of the fan A, so that the air used in the
conveyer duct B is practically the same air circulating through it over and over
again, owing to this air being withdrawn from the same room or compartment Q
as the material is being delivered into. Hence the air in the receiving room Qis
neither added to nor diminished, nor is the degree of atmospheric moisture in the
room altered while the apparatus is working, which in some cases is of much
practical importance.
In order to collect the leaf or other material in an open-topped box-shaped
ruck or receptacle at the delivery end of the conveyor duct B, I keep the delivery
end at a sufficient elevation above the ground or floor that when a downwardly
lirected bend F is applied thereon there is room for the truck or wagon H to be
placed under it, and I apply on the top of the truck a cover J, of wire-netting or
ther foraminous material, with a central hole in it of approximately the size of
he mouth of the conveyor-duct, and I place the truck so that the mouth of the
luct, with or without an elongation G, of flexible material, such as canvas, is fair
ver and the flexible elongation, when used, hanging into the central hole in the
vire-netting cover J. This cover, while allowing the free escape of the air rever-
erating off the bottom and sides of the truck, catches any of the leaf or material
which blows upward along with it, and the same falls back again into the truck.

page_text: $6
The employment of this device obviates any necessity for what is known as a
'stive" or collecting-room.
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. In pneumatic apparatus for elevating or conveying tobacco-leaf or other
material, the combination of a blast-pipe having an enlargement at the upper side
where the material is fed to it, a hopper through which the material is fed into
said blast-pipe, and a flap door or valve between the feed hopper and the blast-pipe
and normally more or less open toward the blast-pipe, whereby when a charge of the
material is fed through the hopper into the blast-pipe through the door temporary
back-pressure of the air-blast pipe is produced against the back of the door and the
door is therefore automatically closed until the said back pressure ceases, substan-
tially as and for the purpose herein before described.
2. The general arrangement or combination of parts substantially as herein-
before described and shown in the accompanying drawings, constituting an
improved apparatus for elevating or conveying tobacco-leaf or other material.
Dated this 7th day of March 1898.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.