Improvements in Pneumatic-tube Conveying Apparatus.
Year: 1890

page_text: Date of Application, 16th July, 1890
Complete Specification Left, 15th Apr., 1891-Accepted, 6th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Pneumatic-tube Conveying Apparatus.
I, WILLIAM HAMILTON BLAKENEY, of 181 North Street, Glasgow, in the
County of Lanark, North Britain, Mechanical and Electrical Engineer, do hereby
declare the nature of this invention to be as follows, that is to say :-
This invention comprises various improvements in pneumatic-tube conveying
apparatus, including improved arrangements for despatching and receiving the
carriers, improved controlling, indicating, and other details, and improved air-
pumping apparatus.
In carrying out the invention according to one modification there is arranged a
central station at or near which the motor apparatus may be conveniently situated,
and from which there radiate a number of pneumatic conveying tubes, each extending
to one end station, or any one or more of them having branches extending to two or
more end stations.
At each central terminus and at each end terminus of a tube the tube is provided
with a lateral despatch branch into which a carrier may be inserted even whilst
another carrier is traversing the main tube and from which the freshly inserted
carrier is started automatically as soon as the main tube is clear. With this
arrangement the operator does not require to watch and wait until a main tube is
clear before inserting a fresh carrier; and a great saving of time is thereby effected
especially at a central station where an operator may have a large number of tubes
to attend to. At each terminus of a tube the discharge of a carrier takes place
through a pair of hinged flaps, which meet at an angle when closed, and the
movement of which is availed of to automatically start a fresh carrier if there is
one in the despatch branch.
The despatch branch at an end station is provided with a close-fitting door which
is opened for inserting a carrier, and when a carrier is thus inserted it moves a
spring or other piece within the branch tube in a manner to complete an electric
circuit which transmits an indicating or controlling action or both to the central
station. Or the inserting of a carrier into an end despatch branch may cause the
transmission of an action through indicating and controlling apparatus of other
kinds hereinafter indicated.
At the central station the end of the despatch branch of a conveying tube is
formed with a segmental cylindrical surface in close contact with which there is
fitted to work on a concentric axis a metal sector formed with a cavity to receive
a carrier. This cavity in the inner position of the sector coincides with and
forms a short continuation of the branch tube; and the sector is turned to expose
the cavity when a carrier is to be inserted, another part of the sector then closing
the branch tube. When the sector is in its inner position its bottom communicates
with a concentrically placed stopcock the plug of which is at the proper time
turned by a lever so as to admit compressed air from a reservoir into the sector
cavity to propel the carrier therefrom and along the conveying tube.
When a
carrier is inserted in the cavity and the sector turned in by means of a handle, the
sector is held by a catch which then drops into the holding position; and on the
carrier reaching the end station the electric current releases the catch and the
sector is by springs turned out again ready for a fresh carrier.. The releasing
of the catch is insured by means of a hammer acted on by a spring, the hammer
itself being held by a delicate catch which is released by an electro magnet
actuated by the current. The hammer is returned to its position by a cam plate

page_text: оц
the stopcock lever which acts on a pin on the hammer when the lever is
turned in.
Whilst a carrier is being propelled from the central station along a conveying
tube the central discharge part of that tube is closed by a slide connected to the
plug lever of the stopcock supplying compressed air to the despatch branch of
the same tube; and when the despatch sector is moved outwards the slide is
withdrawn so as to open the discharge passage. On the sector being next turned
in the plug lever is not moved inwards and the slide is not closed unless the
conveying tube is clear but is retained by a catch which is released on the discharge
of the carrier which is on its way to the central station. The slide is held in its
open position by a rod which extends through a cylinder of small area and also
through a cylinder of larger area these cylinders communicating with each other
only by a very small passage. The rod has two pistons on it, one in each cylinder,
the smaller one acting as a piston valve to put the discharge end of the conveying
tube in communication with a pipe connected to a vessel in which a vacuum is
maintained, in order that the carrier may be propelled towards the central station
by atmospheric pressure operating against a vacuum. The end of the larger
cylinder which communicates with the smaller one by the small passage is connected
to the pressure reservoir by a pipe fitted with a stopcock, and the other end is open
to the atmosphere. This pressure stopcock is opened by means of a connection
with the discharge flaps when a carrier is discharged through them; and the
compressed air then moves the large piston in a manner to cause the small piston to
close the vacuum port into the conveying tube. The same action withdraws the
rod from the slide which then moves to its closed position the plug lever of the
despatch stopcock at the same time moving to its open position. The large piston
is retained in the position into which it has been moved, by a catch engaging with
a notch on an extension of the rod ; and preparatory to the next movement the air
gradually passes from the cylinder by the small passage hereinbefore mentioned,
the supply cock being then closed. The catch retaining the rod is released by a
hammer which is itself released by an electro magnet; and the atmospheric pressure
then moves the larger piston so as to retain the slide in the open position and so as
to open the vacuum port; and the rod also moves back the hammer ready for its
next stroke.
When a carrier is being propelled by compressed air, the air in front of it escapes
from the conveying tube through the discharge flaps which may be delicately
balanced to allow of their opening easily to a sufficient extent; or light flexible
valves may be applied to openings in one or both of the discharge valves; or the
escape of the air may be provided for in any other convenient way. Or the end of
the conveying tube towards which a carrier is moving may be put in communication
with a vessel in which a vacuum is maintained, whilst compressed air is admitted to
the other end. At the discharge end at the central station, or in any case in which
the carrier is propelled against a vacuum, the discharge flaps are arranged so as to
avoid as much as possible the resistance of atmospheric pressure in opening them.
For this purpose the flaps are made with segmental cylindrical parts at their outer
ends concentric with their hinges, and the casing at the end of the tube is made to
completely enclose the flaps so that the pressure on both sides of them is equal, the
segmental parts closing the bottom of the casing when the flaps are closed.
For controlling and indicating I may employ air, water, or other fluid acting in
small pipes with plus or minus pressure; or I may employ electricity.
The
For indicating I place at the central station near each conveying tube, a cylinder
having a loosely fitting piston, or any equivalent device such as a bellows; and I
connect the same by a small pipe to the conveying tube near the end station.
piston or equivalent part is arranged to move a disk or indicator, and on a carrier
being conveyed along the tube the consequent change of pressure causes the
indicator to move into view or into a position indicating that a carrier is in the
particular tube. On the carrier reaching the end station the indicator returns
to its normal position. To insure the working of the indicator piston, I, in some

page_text: cases, apply a spring valve in it so that pressure may pass to the further side of it,
and to cause it to move back quickly as soon as the pressure on the side communi-
cating with the conveying tube becomes normal.
With the fluid indicating apparatus described there may be combined a connection
with an electric bell, to give an audible indication and save the attendant's time
in watching.
According to another modification the indicating apparatus is a Utube of glass
partly filled with a suitable liquid and having one leg connected to the conveying
tube, the liquid rising in the other leg with an increase of pressure and vice versa.
If mercury is the liquid used, it may be arranged to complete an electric circuit and
cause the ringing of a bell.
When applying electrical controlling and indicating apparatus to pneumatic
conveying tubes in a manner to obtain automatic action, I employ an improved
double-action reversing key or device comprising a slide or movable piece carrying
two metallic contact pieces insulated from each other, and two pairs of stationary
contact pieces, any or all of which may be spring blades or be held by springs.
The line wire is connected to a binding screw to which are secured wires connected
to two of the stationary contact pieces which are diagonally opposite to each other:
and the earth wire is connected to a binding screw to which are secured wires
connected to the other two diagonally opposite stationary contact pieces.
the stationary contact pieces are connected one to each pole of the battery; and the
slide causes the electric current to pass along the line wire in one direction or
the opposite accordingly as it is put into contact with one or the other pair of
stationary contact pieces.
Two of
I employ special arrangements of valves and apparatus for working pneumatic
indicators, and for working the valves by which the fluid pressure is controlled at
the central station. In one modification a small pipe extends from each end station
to the central station at which latter it is connected to an indicator cylinder or
At the end station the small pipe
equivalent arranged as hereinbefore described.
has in connection with it a small valve of a conical or other form acted on by a
spring, or the valve may be a spring blade; and this valve or a part on it protrudes
into the conveying tube and it is in consequence opened by contact of a carrier
when inserted in the tube. The opening of the valve by allowing air to escape
from the indicator cylinder allows the piston to be moved by pressure from the
pressure reservoir and thereby causes the indicator to show that a carrier has
entered the conveying tube; or the piston nay cause the ringing of an electric bell.
Besides or instead of simply moving an indicator, the piston may move a valve
putting the particular conveying tube into communication with the
reservoir, and thereby causing the carrier to be drawn along the tube.
when a carrier reaches an end station it may by the same or similar apparatus cause
the closing of the valve admitting the pressure by which it was propelled from the
central station.
vacuum
Similarly
When one conveying tube branches into two I fit at the junction or fork a flap
valve with an external lever to shift or switch it, the lever being connected to the
piston rod of a small cylinder actuated by means of fluid in a small pipe extending
to the central station, where a suitable valve allows of pressure or suction being
applied as required to move the switch flap into either of its two positions. At the
junction and connected preferably, to the piston rod of the cylinder there, I arrange
an electric switch and two wires connected to the central station and two other
When it is wished to
wires connected to the end stations of the two branches.
send a carrier from an end station which happens to be shut off at the junction the
electric switch causes a bell at the central station to continue to ring until the
attendant there can arrange for the transmission of the carrier.
indication given for the same purpose may be varied in different cases; or similar
indications may be obtained by means of suitable adaptations of my arrangements
of small pipes with fluid under plus or minus pressure. In some cases where a small
The kind of

page_text: pipe is used as hereinbefore described it may be availed of also as an electric
conductor.
In using electrical controlling appliances I in some cases employ an electro
magnet to act directly on a valve for opening a communication with a vacuum or
pressure pipe. The valve is a light disk or flap valve of soft iron or provided with
a thin plate or strip of soft iron; and the electro magnet is adjustable above it,
whilst to prevent the valve from sticking to the magnet when the current is
switched off complete contact is prevented by a thin piece of non-magnetic
material.
In order to simplify the motor apparatus I employ the same cylinder or cylinders
to compress the air and to produce vacuum, but to insure a full supply of air for
each compressing stroke I arrange inlet valves to admit air freely at the com-
mencement of that stroke or just before it, and appliances to insure the closing of
the communications with the vacuum reservoir before the opening of such inlet
valves.
Dated this Fifteenth day of Tule 1900
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Pneumatic Tube Conveying Apparatus.
I, WILLIAM HAMILTON BLAKENEY, sometime of 181 North Street, but now
of 33 Bath Street, Glasgow, in the County of Lanark, North Britain, Mechanical
and Electrical Engineer, 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, that is to say:―
My said invention comprises various improvements in pneumatic tube conveying
apparatus, including improved arrangements for despatching and receiving the
carriers, improved controlling, indicating and other details, and improved air-
pumping apparatus.
The description of my improvements is assisted by five sheets of explanatory
drawings hereunto appended and hereinafter referred to.
Figures 1, and 2, on Sheet 1, of the drawings are vertical sections as at right
angles to each other of the sending apparatus at a central station.
Figure 3, Sheet 2, is a vertical section of the receiving apparatus at a central
station.
Figures 4, 5, and 6, Sheet 3, show sending and receiving apparatus at an end
station, Figure 4, being a side elevation, Figure 5, a vertical section as at right
angles to Figure 4, and Figure 6, a sectional view of a modification of the receiving
apparatus.
Figures 7 to 16, Sheets 4, and 5, comprise views of details and diagrams herein-
after described.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
In carrying out my invention according to one modification there is arranged a
central station at or near which the motor apparatus may be conveniently situated,
and from which there radiate a number of pneumatic conveying tubes, T, each
extending to one end station, or any one or more of them having branches extending
to two or more end stations.
At each central terminus and at each end terminus of a tube, T, the tube is
provided with a lateral despatch branch, DI, D2, into which a carrier may be
inserted even whilst another carrier is traversing the main tube, T, and from which
the freshly inserted carrier is started automatically as soon as the main tube is
clear. With this arrangement the operator does not require to watch and wait

page_text: until a main tube is clear before inserting a fresh carrier; and a great saving of
time is thereby effected especially at a central station where an operator may have
a large number of tubes to attend to.
At each terminus of a tube T, the discharge of a carrier takes place through a
pair of hinged flaps, F, (Figures 3 to 6) which meet at an angle when closed, and
the movement of which is availed of to automatically start a fresh carrier if there
is one in the despatch branch D 1 or D 2.
The despatch branch, D2, at an end station is provided with a close-fitting
door, D3, which is opened for inserting a carrier, and when a carrier is thus
inserted it moves a spring, or other piece or key, C, within the branch tube D 2, in
a manner to complete an electric circuit which transmits an indicating or controlling
action or both to the central station. Or the inserting of a carrier into an end
despatch tube, D2, may cause the transmission of an action through indicating and
controlling apparatus of other kinds hereinafter indicated. In the arrangement
shown in Figure 5, the normal position of the spring contact piece, C, is to
electrically connect a conducting-wire terminal, C1, (to which the piece, C, is
permanently fixed) with a terminal, C 2, the wire of which goes to earth, but when
the piece, C, is pressed outwards by an inserted carrier it makes contact with a
third terminal, C3, to which the line wire is fixed.
At the central station the end of the despatch branch, D 1, of a conveying tube, T,
is formed with a segmental cylindrical surface, D 4, in close contact with which there
is fitted on a concentric axis a metal sector, S, formed with a cavity, S 1, to receive
a carrier. This cavity, S 1, in the inner position (Figure 1,) coincides with and
forms a short continuation of the branch tube, D 1, and the sector, S, is turned to
expose the cavity, S1, when a carrier is to be inserted another part, S 2, of the
sector then closing the branch tube, D 1. When the sector, S, is in its inner
position its bottom communicates with a concentrically placed stopcock, S3, the
plug, S4, of which is at the proper time turned so as to admit compressed air from
a pressure pipe, P, connected to a reservoir, into the sector cavity, S 1, to propel
the carrier therefrom and from the branch tube, D 1, into and along the main
conveying tube, T. When a carrier is inserted in the cavity, S 1, and the sector, S,
turned in, the sector remains in that position until the carrier reaches the end
station, and then an electric current by releasing a catch causes the sector to be
turned out again ready for a fresh carrier. A pair of levers, L, fixed on the stop-
cock plug, S4, are held in the open position by a weighted catch, L 1, indicated by
dotted lines in Figure 1, and which is made with a horn, L 2, to be acted on by a
hammer, L 3. The hammer, L3, which might be actuated by a spring, but which
is shown as arranged to act by its own weight, is held up by a catch, A, acting as
an armature of an electro-magnet, M. The levers, L, are connected by a pair of
links, L 4, and a crosshead to the rod of a piston, L 5, in a cylinder, L 6, the inner
end of which is connected by a small pipe, V, fitted with a regulating screw, to a
reservoir in which a vacuum is maintained. Atmospheric pressure acting on the
outside of the piston, L 5, operates (instead of a spring as provisionally proposed)
for moving back the levers, L, and the stopcock plug, S4; and a projection, L 8,
on the crosshead of the links, L4, acts like a cam on an arm, L9, of the
hammer L 3, to return the last into its elevated position. The sector, S, may be
pushed in by hand after inserting a carrier. I now however prefer to push in by
hand a rod, S 5, and to leave the sector to be moved in automatically as soon as
the main tube, T, is clear for the passage of the carrier. The rod, S 5, is connected
to a lever, S6, connected by a spring, S7, to the framing, and formed with a
catch, S 8, which catch on the lever, S6, being first pushed over engages with a
spring catch, S9, so as to be held in the pushed over position. On the sector, S,
being subsequently moved into the inner position an arm, 1 S, on it depresses the
spring catch, S 9, and allows the lever, S6, to be moved back by its spring, S 7.
The lever, S6, is fixed on the plug of a stopcock, I, which, when open, admits air
from the pressure pipe, P, into a small pipe, I 1, connected to the cylinder, L 6, to

page_text: more outwards the piston, L 5, and thereby move the levers, L, into the position
in which they are indicated in Figure, 1. This action opens the valve plug, S4,
and by the links, T 2, moves the slide, B, into the closing position, a cross bar, T 3,
at the ends of the links also moving the sector S, inwards if not already so moved.
Whilst a carrier is. being propelled from the central station along a conveying
tube, T, the central discharge part, T 1, of that tube is closed by a slide, B,
connected by links, T 2, to the plug levers, L, of the stopcock, S4, supplying
compressed air to the despatch branch, D 1, of the same tube, and when the
despatch sector, S, is moved outwards the slide, B, is withdrawn so as to open the
discharge passage, T 1. The plug levers, L, are not again moved and the slide, B,
is not closed unless the conveying tube, T, is clear, the slide being retained by a
catch, B1, which is released on the discharge of the carrier which is on its way to
the central station. The catch for holding the slide, B, in its open position is a
rod, B1, which passes up beyond a part, 12, in the slide when the slide is open the
part, B2, having an antifriction roller fitted to it to prevent sticking. This
rod, B1, extends through a cylinder, B3, of small area, and also through a
cylinder, B4, of larger area, these cylinders communicating with each other only
by a very small passage, B 5. The rod B 1, has on it two pistons, B6, B7, one in
each cylinder, the smaller one B 6, acting as a piston valve to put the discharge
end, T 1, of the conveying tube in communication with a pipe, V 1, connected to a
vessel or reservoir in which a vacuum is maintained, in order that the carrier may
be propelled towards the central station by atmospheric pressure operating against
a vacuum, (the atmosphere having access through a light check valve, D 5, to the
extreme end of the end-station despatch branch-pipe, D 2). The end of the larger
cylinder, B4, which communicates with the smaller one by the small passage, B 5,
is connected to the pressure reservoir by the pipe, P 1, fitted with a stopcock, P 2,
and the other end is open to the atmosphere. This pressure stopcock, P2, is
opened by means of a link, P 3, connecting a lever on it to a lever on one of the
discharge flaps, F, when a carrier is discharged through those flaps; and the com-
pressed air then moves the large piston, B7, in a manner to cause the small piston
to close the vacuum port, V 2, into the conveying tube, T 1, T. The same action
withdraws the rod, B1, from the slide, B, and the rod, B1, is retained in the
position into which it has been lowered by the large piston, B 7, by a catch lever, E,
engaging in a notch formed in a lower extension of the rod; and preparatory to the
next movement the air gradually passes from the cylinder, B4, by the small
passage, B5, the pressure supply cock, P2, being then closed. The catch lever, E,
is released by a hammer, E 1, which is itself released by a catch, A 1, arranged as
the armature of an electro magnet, M 1, and the atmospheric pressure then moves
up the larger piston, B 7, and the rod, B 1, so as to retain the slide, B, in the open
position, and so as to open the vacuum port, V 2, and the rod B 1, by means of an
arm, E2, fixed to it, moves back the hainmer, E 1, ready for its next stroke.
With the view of insuring the proper action of various parts, the piston rod, B 1,
has fixed to its lower end a cross bar, F 1, which at one side is connected to levers
on the discharge flaps, F, by links, F 2, attached to a tube, F 3, containing a
spring, F4, acting between the bottom annular end of the tube, and a head on the
upper end of a rod, F 5, fixed to the cross bar, F 1, a second spring, F 6, being
placed on the rod, F 5, between the tube, F 3, and the cross bar F1. When the
cross bar, F 1, descends it, through the connections described, insures the closing of
the flaps, F, so that the internal vacuum may be effective when the vacuum
port, V 2, is next opened. The lower spring, F 6, which is of moderate strength is
compressed by the opening of the flaps, F, prior to the opening of the pressure
cock, P2, and when the crossbar, FI, descends the other spring, F 4, which is
stronger overcomes the lower spring and closes the flaps. A. second arm, F 7, on
the crossbar is connected by a cord or wire, F 8, to a spring catch, P 4, and when
the rod, B 1, reaches its lowest position, pulls down the catch clear of an arm, P 5,
on the pressure cock plug, P 2, and allows that plug to return to its closed position.

page_text: When the rod, B 1, reaches its lowest position it, also moves an electric switch or
key, C4, into a position to cause the transmission of a signal indicating that the
parts are in the position for despatching a carrier from the central station.
When a carrier is being propelled by compressed air, the air in front of it escapes
from the conveying tube, T, through the discharge flaps, F, which may be
delicately balanced to allow of their opening easily to a sufficient extent; or light
flexible valves may be applied to openings in one or both of the discharge valves;
or the escape of air may be provided for in any other convenient way. Or the end
of a conveying tube, T, towards which a carrier is moving may be put into com-
munication with a vacuum vessel or reservoir, whilst compressed air is admitted to
the other end. At the discharge end (T 1) at the central station, or in any case in
which the carrier is propelled against a vacuum, the discharge flaps, F, may be
arranged as shown in Figure 6, so as to avoid as much as possible the resistance of
atmospheric pressure in opening them. For this purpose the flaps F, Figure 6, are
made with segmental cylindrical parts, 1 F, at their outer ends concentric with their
hinges, and the casing, 2 F, at the end of the tube, T, is made to completely enclose
the flaps, so that the pressure on both sides of them is equal, the segmental parts, 1 F,
closing the bottom of the casing when the flaps are closed. The flaps, F, have
holes made in them, and the connection with the vacuum pipe, V 3, may be at the
outer side of either of them.
For controlling and indicating I may employ air, water, or other fluid acting in
small pipes, G, with plus or minus pressure; or I may employ electricity.
For indicating, according to one modification, I place at the central station near
each conveying tube, T, a cylinder, G 1, such as is shown in Figures 7, 8, and 10,
having a loosely fitting piston, G 2, or any equivalent device such as a bellows;
and I connect the same by a small pipe, G, to the conveying tube, T, near the end
station. The piston, G2, or equivalent part, is arranged to move a disk or
indicator, 12, and on a carrier being conveyed along the tube the consequent
change of pressure causes the indicator, I2, to move into view, or into a position
indicating that a carrier is in the particular tube. On the carrier reaching the end
station, the indicator, I 2, returns to its normal position. To insure the working of
the indicator piston, G2, I, in some cases, employ a small passage, G3, through it
as shown in Figure 7, or a valve, G4, as shown in Figure 10, so that pressure
entering by the pipe, G, may pass to the further side of it, and cause it to move
back quickly as soon as the pressure in the pipe, G, becomes normal.
With the fluid indicating apparatus described there may be combined a connec-
tion with an electric bell, to give an audible indication and save the attendants time
in watching.
According to another modification the indicating apparatus is a U tube of glass
partly filled with a suitable liquid and having one leg connected to the conveying
tube, T, the liquid rising in the other leg with an increase of pressure and vice versa.
If mercury is the liquid used, it may be arranged to complete an electric circuit
and cause the ringing of a bell.
When applying electrical controlling and indicating apparatus to pneumatic
conveying tubes, T, in a manner to obtain automatic action, I employ an improved
double-action reversing key or device, one modification of which is shown in
Figure 12. The device comprises a slide or movable piece, K, carrying two
metallic contact pieces, K1, K2, insulated from each other, and two pairs of
stationary contact pieces, K 3, K4, K 5, K 6, any or all of which may be spring
blades or be held by springs. The line wire, W, is connected to a binding
screw, W 1, to which are secured wires, W 2, W 3, connected to two, K 3, K 6, of
the stationary contact pieces which are diagonally opposite to each other; and the
earth wire, Y, is connected to a binding screw, Y 1, to which are secured wires, Y 2,
Y3, to the other two diagonally opposite stationary contact pieces, K4, K5. The
movable contact pieces K1, K2, are connected one to each pole of a battery, Z;
and the slide or movable piece, K, causes the electric current to pass along the line
wire, W, in one direction or the other accordingly as it is put into contact with one

page_text: or the other pair of stationary contact pieces, K 3, K 4, or K 5, K 6. A modifica-
tion of the double-action reversing key is shown in Figures 4, and 5, as applied in
connection with the discharge flaps, F, at an end station, the movable piece, K,
being in the form of a lever, which is acted on by a cam projection on one of the
flaps F. The same device is also shown in the diagram Figure 13, which also
shows (at the left-hand side) the electric arrangements at the central station.
At C 4, is the key worked by the piston, B7, and rod, Bl. At C, is the key or
contact piece worked by inserting a carrier at an end station.
I employ special arrangements of valves and apparatus for working pneumatic
indicators, and for working the valves by which the fluid pressure is controlled at
the central station. In one modification a small pipe, G, extends from each end
station at which latter it is connected to an indicator cylinder, G 1, or equivalent
arranged as herein before described. At the end station the small pipe, G, has in
connection with it as shown in Figure 9, a small valve, (+ 5, of a conical or other
form acted on by a spring (or the valve may be a spring blade); and this
valve G5, or a part on it protrudes into the despatch branch, D2, of the conveying
tube, and it is in consequence opened by a spring piece, C, moved by a carrier when
inserted in the tube. The opening of the valve, G5, by allowing air to escape
from the indicator cylinder, G 1, causes the piston, G2, acted on by compressed air
to move the indicator, 12, so as to show that a carrier has entered the conveying
tube, T or the piston, G 2, may cause the ringing of an electric bell. Besides, or
instead of simply moving an indicator, the piston, G2, may move a valve putting
the particular conveying tube into communication with the vacuum reservoir, and
thereby causing the carrier to be drawn along the tube. Similarly when a carrier
reaches an end station it may by the same or similar apparatus cause the closing of
the valve, S4, admitting the pressure by which it was propelled from the central
station. An arrangement for this purpose is shown in Figure 11, the valve, G 5,
for admitting air to the small pipe, G, being connected to one of the discharge
flaps, F, so as to be opened when a carrier passes out.
When one conveying tube, T, branches into two or more as shown in Figure 14,
Sheet 5, I fit at each junction or fork a flap valve, T 3, with an external lever, T 4,
to shift or switch it, the lever being connected to the piston rod of a small
cylinder, G7, actuated by means of fluid in a small pipe, G 8, extending to the
central station, where a suitable valve, G 9, allows of pressure or suction being
applied as required to move the switch flap, T3, into either of its two positions.
At each junction, and connected, preferably, to the piston rod of the cylinder, G 7,
there, I arrange an electric switch, Q and two wires connected to the central station
and two other wires connected to the end stations of the two branches from each
junction. When it is wished to send a carrier from an end station which happens
to be shut off at the junction the electric switch, Q, causes a bell at the central
station to continue to ring until the attendant there can arrange for the transmission
of the carrier. The kind of indication given for the same purpose may be varied in
different cases;
or similar indications may be obtained by means of suitable
adaptations of my arrangements of small pipes with fluid under plus or minus
pressure. In some cases where a small pipe is used as hereinbefore described it may
be availed of also as an electric conductor. Figure 14, shows in diagram
venient arrangement of electrical connections between the branch junctions and the
central station, and end stations, the parts appertaining to the central station being
at the lower left hand part of the diagram.
a con-
In using electrical controlling appliances I in some cases employ an arrangement
such as is shown in section in Figure 15, in which an electro magnet, M 3, is applied
to act directly on a valve, G5, for opening a communication with a vacuum or
pressure pipe, G. The valve, G 5, is in this case a light disk, or it might be a flap
valve, of soft iron or provided with a thin plate or strip of soft iron to act as an
armature; and the electro magnet, M 3, is adjustable above it, whilst to prevent
the valve from sticking to the magnet when the current is switched off complete
contact is prevented by a thin piece of non-magnetic material.

page_text: In order to simplify the motor apparatus I employ the same cylinder or cylinders
to compress the air and to produce a vacuum, but to insure a full supply of air for
each compressing stroke I arrange special inlet valves to admit air freely from the
atmosphere at the commencement of the compressing stroke or just before it. This
may be done in various ways but a simple arrangement is shown in section in
Figure 16. The piston, X, in the cylinder, X 1, on approaching each end of its
stroke comes in contact with the stem of a valve, X2, controlling a passage, X 3,
by which air can enter the other end of the cylinder, the air entering each
passage, X3, through a check valve, X4, which prevents return outwards when
the air becomes compressed. The ends of the cylinder are also provided with the
usual inlet and outlet check valves and passages communicating with the pressure
and vacuum reservoirs.
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 combination of parts constituting my improved pneumatic-tube conveying
apparatus substantially as hereinbefore described with reference to Figures 1 to 5
of the accompanying drawings.
2. The improved central-station despatch apparatus substantially as hereinbefore
described with reference to Figures 1 and 2 of the accompanying drawings.
3. The improved central-station receiving apparatus substantially as hereinbefore
described with reference to Figure 3, of the accompanying drawings.
4. The improved end-station despatch and receiving apparatus substantially as
hereinbefore described with reference to Figures 4, and 5, of the accompanying
drawings.
5. The modification of the receiving apparatus hereinbefore described with
reference to Figure 6, of the accompanying drawings.
6. In connection with pneumatic-tube conveying apparatus the providing of small
pipes for the passage of air or other fluid under plus or minus pressure for indicating
or controlling or both purposes between stations substantially in any of the modes
hereinbefore described.
7. In connection with pneumatic-tube conveying apparatus and electrical indicating
or controlling connections between stations, the improved double-action reversing
key or device substantially as hercin before described more particularly with reference
to Figure 12, of the accompanying drawings.
8. In connection with pneumatic tube conveying apparatus and electrical con-
nections for indicating or controlling or both purposes between stations, providing
for the certain release of holding catches by arranging hammers held and released
by electro magnets substantially as hereinbefore described with reference to
Figures 1 and 3, of the accompanying drawings.
9. The improved arrangements in connection with the junctions of branch
pneumatic conveying tubes for moving the switch flaps by means of fluid plus or
minus pressure in small pipes, and for electrical indicating or controlling or both
purposes in connection with the switch flaps substantially as hereinbefore described.
10. The producing of plus and minus pressure for pneumatic-tube conveying
apparatus by means of the same cylinder and piston, the said cylinder being fitted
with special valves for admitting a full supply of air at the commencement of each
compressing stroke substantially as hereinbefore described with reference to
Figure 16, of the accompanying drawings.
Dated this Fourteenth day of April 1891.
EDMUND HUNT,
Applicant's Agent.