New and Useful Improvement in Air Locks.
Year: 1894

page_text: Date of Application, 27th Jan., 1894-Accepted, 9th June, 1894
COMPLETE SPECIFICATION.
New and Useful Improvement in Air Locks.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a communi-
cation to me from abroad by Daniel Edward Moran, of the City of New York,
State of New York, United States of America, Mechanical Engineer,) 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 :-
Figure 1 is a vertical section through the lock showing both valves closed, the
open position of lower valve being shown in dotted lines.
Figure 2 is a vertical section through the centre of the lock at right angles to
section shown in Figure 1 showing both valves closed, the open position of the
upper valve being shown in dotted lines.
Figure 3 is a vertical section of the outer shell showing the inner shell lower
valve-seat, valve and link motion in detail.
Figure 4 is a vertical section through half the upper valve shown in connection
with a stuffing-box on the hoisting rope.
Figure 5 is a side view of half the upper valve with its connections and moving
parts, the position when open being shown in dotted lines.
Figure 6 is a top view of the valve when closed, the valve seat being removed to
show the valve.
Figure 7 is a vertical section of valve on line S S showing manner of attaching
gasket at joint.
Figure 8 is a vertical section through centre of upper valve showing method of
using packing around the hoisting rope.
Figure 9 is a vertical section of a modification of the upper valve, where the
sections of valve roll to and from the seat.
Figure 10 is a vertical section of a modification of air lock in which all the
valves are hinged so as to be turned to or away from the valve seats.
Figure 11 is a top view of the upper valve shown in Figure 10 closed.
Figure 12 is a top view of another form of upper valve.
Figure 13 is a section through the same.
This my invention relates to air-locks for use in work carried on under air
pressure greater than that of the atmosphere, or what is known as the pneumatic
method, and consists in the combination in an air-lock of a valve adapted to close
around and open from a rope at or near the centre of the valve while the rope
is bearing a load, and the variations and modifications hereinafter specified and
claimed.
In the constructions of tunnels, piers and other underground or under water
works, it is usual to connect the working chamber with the outer air by a tube or
shaft having one end opening in the working chamber and the other end reaching
to the outer air, through which access is had to and from the working chamber
tunnel heading or caisson.
In order to give access to and from the working chamber an air-lock is provided
consisting usually of two doors one on the inner and the other on the outer side of
an air chamber, connecting pipes and valves being arranged to equalize the
pressure in the air chamber with the working chamber or outer air in accordance
with which one the lock is to be opened into.
In the use of such devices it is necessary in passing material from the working

page_text: chamber to the outer air to close the outer door, open the inner door and move the
material into the air chamber or lock, and rest it there, close the inner door,
equalize the pressure with the outer air and again move the material to the
outer air.
Where tackle is used in moving the material as is usually the case one tackle is
used to bring the material in the air chamber or lock and a different tackle in
moving it from the air chamber, making two handlings necessary in passing from
the working chamber to the outer air.
The purpose of this my invention is to move the material from or to the working
chamber in one continuous journey without the necessity of handling it or
changing tackle in the air chamber or lock or of having special appliances on the
bucket or carriage.
I usually place my air-lock at the top of the shaft or end of the tunnel away
from the working chamber, but it may be placed at any part of the shaft or tunnel
without departing from my invention.
I will now proceed to describe my invention as applied at the outer or upper end
of a shaft in connection with an ordinary dump bucket but it is manifest that it
may be applied to tunnels, or other places where air locks are used or for locking
through otner objects than a bucket.
The upper part of the lock is in the form of a rectangular box C1, C2, C3, C4,
Figures 1 and 2 having circular openings in the top and bottom affording a passage
way through the box. The opening in the top can be closed by the upper
valve K K Figures 1, 2, 4, 5 and 6. This valve K K is in two halves and when
not in use hangs in the space M Figures 1 and 2 enclosed by the rectangular box
but it is then so disposed as not to interfere with the passage way. The cylindrical
shell Q Figures 1 and 2 is attached to the bottom of the box C3, C4, so as to
correspond with the opening through the bottom of the box. This shell Q is open
at both ends but the lower end is reinforced so as to form a seat V Figures 1 and 2
for the lower valve W Figures 1 and 2. The space L within the shell Q is always
open to the space M, and forms an extension of the passage way through the
box C. The space so formed will hereafter be referred to as the bucket space.
The box C, C2, C3, C4, is carried by an outer jacket O which connects at its
lower end with the shaft proper P and makes a continuous airtight connection
between the two. The annular space R between the cylindrical shell Q and the
jacket O, accommodates the lower valve W and its moving parts when it is open.
This space always has direct air communication with the shaft proper.
The openings in the rectangular box and the cylindrical shell Q are all
preferably approximately of the same diameter as the diameter of the shaft so that
if both valves be opened a continuous passage way will be formed through the lock
and in line with and equal in diameter to the shaft.
The upper valve K K' fits against a continuous circular valve seat B arranged
on the under side of the top plate, of the rectangular box C¹, C².
The valve is in two equal or nearly equal halves so that each half is
approximately a semi-circle. Each half or leaf of the valve is actuated as
follows:-
The shafts e and e Figures 1, 2, 5 and 6, each are held in bearings in the
shell C³, C², one end of each shaft projects through the shell which is provided.
with a packing box at the place the shafts e, e, pass through. On the outer or
projecting end of each shaft is a lever or other handle by which the shaft is to be
turned, and a counterweight m to keep the valve in its place against the
valve seat.
Rigidly keyed to each shaft e e, within the shell are two arms ff which carry in
bearings made for that purpose trunnions gg on the side of the half valve. The
trunnions should be about midway of the side of the half valve, and turn treely in
the arms ff.
Rigidly attached to the under side of the half-valve, in line with the trunnions
are two arms hh, projecting at right angles to the plane of the half valves.
At a

page_text: point in each of the arms hh distant from the trunnions 9 g equal to the distance
of the bearing for the trunnion in the arm f from the shaft e is a pin or projection i
which rides in a groove ; made in a plate provided for that purpose within
the shell.
The slot is made at an angle of 45° from the valve seat and is sufficiently long
to permit the pin i to move without being stopped by the length of the slot.
I have shown two arms h h for each half-valve, but one for each is sufficient.
I will now describe the operation of one of the half valves:
The valve being closed against the seat as shown in Figures 1 and 2, the shaft e
is turned so as to throw the arms ff through the dotted quarter-circle shown in
Figure 4 to the position shown in dotted lines in that same figure; as the arms ƒƒ
pass around the pin i in the slot is forced through the slot to its extreme lower
end, the shaft e, trunnion 9 and pin i are in one straight line when the half valve is
midway between the closed position shown in solid lines, and the open position
shown in dotted lines in Figure 4. As the shaft e turns the half valve moves
toward the position shown in dotted lines, the pin travels up through the slot j to
its upper end as shown in dotted lines. Thus the half valve is made to revolve a
quarter-circle so that what is the upper face when closed against the valve seat is
turned against the shell when the valve is open.
The other half valve is operated in the like manner. By this arrangement the
valve is pressed against the valve-seat more uniformly than if hinged, when it is
removed it is stowed away out of the clear passage of the bucket space, and does
not interfere with any bucket or other thing that may be in the bucket chamber.
Where the edges of the two parts K K' come together lips or flanges are made to
give a more perfect joint and one part may be provided with dowel pius and the
other with holes through the flange to receive the dowel pins and these flanges are
made so that a gasket or rubber or other material may be carried by one of them
as is shown in Figure 7.
The valve K, K' Figure 2 has at its centre an opening or hole N shown in
Figure 6 one half the opening or hole being in one part K and the other half in K'.
The lip or flange p. Figure 7 on the edges of the parts K K' may follow around
the opening N. The opening N is made to conform to the rope or cable which is
to pass through it.
About the hole NI may arrange a stuffing box in two halves as shown in
Figures 4, 5 and 6 or flexible packing arranged in some other way, so as to make
a close joint with the cable, such device is shown in Figure 8 where a circular
groove is cut in the face of the top of the hole N, and in each portion of the groove
packing is secured, so that when the parts K K are brought together there will be
a continuous packing about the cable between it and the half valves K K¹.
To make the joint about the cable more secure a stuffing box T Figures 4 and 5
is placed on the cable and properly adjusted to make a close joint with it as shown
in Figures 4, 5 and 6. To the stuffing box is attached a thimble U preferably
screwed into the stuffing box, but it may be formed as part of the stuffing box.
The thimble has on the other end a projecting flange 1, to the thimble is fitted a
piece of hose or other packing 2 and about the thimble and lying on the projecting
flange 1 is a gasket or packing 3. The hose or packing 2 may be omitted and the
gasket used alone, or the gasket may be omitted and the hose used, but I have
found it advantageous to use both.
The valve K K' closes against the thimble and hose 2 and makes a close joint
with it, and the gasket forms a seal about the hole N when the air pressure is
turned in the chamber of the air lock.
I will now proceed to describe the lower valve of my air-lock.
On the lower end of the body Q at V, I form a seat for the lower valve W to
close against, Figures 1 and 2. This seat is preferably circular and flat. The
valve W is preferably circular and spherical, but. has a flat circular edge which
bears on the seat V when the valve is closed.

page_text: Making the valve W spherical not only increases the strength, but makes it
much easier to swing it in and out of position in its seat.
The valve W is hung from the two axles or shafts 4, 4', one on either side of the
shell Q by means of the slotted links 5, 5. The shafts 4, 4', each passes through a
stuffing box in the outer shell O each has one end supported in a step on the inner
shell Q. These links are loose on the shafts 4, 4' but are securely and rigidly
attached to the valve W. To the shaft 4 is securely attached the arm 6, at one
end and to the shaft 4', is securely attached one end of the arm 6'. The extremities
of these arms 6, 6' are connected by floating links 7, 7', with the slotted links 5, 5¹.
All these parts are accommodated in the annular space R R between the inner and
outer shells. The axles or shafts 4, 41 pass through stuffing boxes 8, 8' attached
to the outer jacket O and are connected outside of the lock by a yoke lever 9. By
means of this arrangement of links the lower valve may be opened or closed by
moving the yoke lever 9, as follows: Moving the yoke from the position shown in
Figure 1 where the valve is shown closed to the position shown in Figure 3 permits
the valve to fall by its own weight through a vertical distance sufficient to insure
clearance between the valve and the valve seat V, during the motion next following.
This vertical motion is permitted and limited by the slots in the links, 51.
Continuing the motion of the yoke and with it, of the shafts 4 and 4' and fixed
arms 6 and 6, it is evident that the connecting links 7, 7' will cause the slotted
links 5, 5 and the attached valve W to revolve with them using the axes 4 and 4¹
as an axis. This is continued until the valve is swung completely out the passage
way into the annular space R as shown in Figure 1 by dotted lines. In closing
the valve the operation is reversed and the valve is rotated on the axles 4 and 4*
until in the position shown in Figure 3 when the links engage with a roller stop
at 10, Figure 3. Further motion of the slotted links and valve around the
axles 4, 4¹ being thereby prevented; continuing the motion of the yoke 9 and the
arms 6 and 6' causes the floating levers 7, 7' to act with a toggle joint motion and
lift the valve until it comes to a bearing on its seat V. On the upper surface of
the valve W, between it and the seat V, I may arrange a gasket of rubber or other
material.
I will now proceed to describe the operation of my lock.
The lower valve W being closed and the upper valve K K' open as shown in
dotted lines in Figure 2, the bucket is lowered into the air lock and the upper
valve K K closed so as to encircle the rope or cable and make a close joint at the
meeting edges. The cock 21 which opens between the air chamber or lock and the
outer air is closed and the cock 22 opening between the shaft and the air chamber
or lock is opened thereby admitting air pressure under the valve K K' which acts
to keep it firmly on its seat B. When the air pressure in the air chamber and
shaft have become equal, the valve W is lowered from its seat and swung to one
side as shown in dotted lines in Figure 1, the bucket is now lowered into shaft by
the cable passing through the closed valve K K'. The bucket may now be lowered
to the caisson, emptied of its contents or filled and raised again until the bucket is
again in the bucket chamber, when the valve W is closed; the cock 22 closed and
cock 21 opened thus relieving the air pressure in the air lock and freeing the
valve K K when it may readily be opened and the bucket raised by the cable and
emptied or filled ready for another descent. Thus the bucket is borne by the cable
continuously in its passage into, through and out of the air lock.
It is manifest that when the packing box shown in Figures 4 and 5 is used the
flange on the thimble is pressed by the air pressure in the air lock against the
valve K K and by means of the interposed gasket a close joint made. When
the bucket is raised away from the air chamber the packing box remains on the
cable near the hook and swings with it until the packing box is again brought to
its position in the valve K, K¹; where it is held during the descent of the cable
through the air lock to the shaft.
I have described my invention as applied to a vertical shaft but it is manifest

page_text: that I may apply it to tunnel or side hill operations or other places without-
departing from the nature of my invention.
When the air lock is applied to tunnels it should be outside the tunnel so that
the lever 9 may be operated over the air-lock on a horizontal axis. It would be
easier to operate the valves K K¹ or upper valves with the shafts e e¹ also vertical,.
so that in their operation the valves K K' would be turned rather than raised and
lowered.
Figure 9 shows a modification of the upper valve wherein the half valves K K
are borne on rollers on tracks below the valve seat, so arranged that the valves.
will fall upon the tracks when the air pressure is removed from the bucket.
space M, when the half valves K K' may be moved by admitting steam or air
pressure to the cylinders Z, Z, so that the piston is pushed to the other extremity
of the cylinder thereby opening the valves, leaving a free passage through the-
opening in the air lock." When the cable is again in position steam is admitted to-
the other end of the cylinders and the half valves are pushed together, the air
pressure turned on to the space M, and the valves K K' thereby raised against the
valve seat making a close connection.
It is manifest that the form of the valves with the steam operating attachment.
shown in Figure 9 may be duplicated in the air lock, and one used as an upper and
another as a lower valve making both valves operated by steam.
Figure 10 shows a section of a modification of which Figure 11 is a top view..
In this modification the upper shell I and the lower shell H are each made of
square cross-section and are higher than in the form last described. The upper-
valve is made in two parts 30, 31, each being hinged within the shell I at 33, 34,.
to eyes provided for that purpose. The valves each have an eye or ring in the
face by which they may be raised up against the seat L as 31 is shown in
Figure 10. The meeting edges of the valves 30 and 31 are provided with a flange
and with the hole or perforation N, as in the before described valve. The air
cocks 21 and 22 are arranged to equalize the pressure in the air lock. The lower
valve may be made as an ordinary hinged valve if preferred, and shown in
Figures 10 and 11, where the valve 35 is hinged on the shaft 36 one end of which
passes through the side of the shell H, the passage being sealed by a stuffing. box..
The valve 35 is keyed to the shaft 36 as is the lever 37, so that the movement of.
the lever will move the valve to or away from the seat provided for it.
The valve 35 is so hung that it will swing clear of the opening in the air lock
when open. The shell for the valve is much larger in this form of construction.
than in that first described.
Another form of valve is shown in Figure 12, where one continuous upper valve.
is used, through which from the edge further from the hinge a slot is cut to the :
hole N in the centre, the slot is provided with a slide 24 to close the slot, so as to
leave passage only for the rope or cable. The slide rests in grooves on the under
side of the valve and has a ring at or near the edge by which it may be moved in
and out over the slot, each side of the slot is provided with a seat for the slide to
make a close joint when in position to close the slot. Figure 13 is a cross section
of the valve.
. The valve shown in Figure 12 is intended to be hinged at one side below the
valve seat of the upper valve, so that when open it will swing in the bucket.
chamber. M which should be made sufficiently large to accommodate it.
The bucket having been lowered into the bucket chamber M the valve is swung
up against the valve seat the rope passing through the slot in the valve until it
reaches the centre of the valve. The slide 24 is then inserted through an opening.
in the wall of the air chamber below the valve seat into the grooves on either side
of the slot made to receive it, until the slot is closed excepting the hole N at the-
centre.
There are other forms in which I may make the valves without departing from.
my invention, in which the valve will close around the rope and open from it while-
the rope is bearing a load.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination in an air lock of a two part valve opening from and closing
toward the centre, with a seat on the inner side of the air lock, substantially as
specified.
2. The combination in an air lock of a two part valve opening from and closing
toward the centre, with steam cylinders for operating the same, substantially as
specified and set forth.
3. The combination in an air lock of a two part valve with a rope opening at the
centre with a seat on the inner side of the air lock and the rope at the centre
against which the valve closes, substantially as specified.
4. The combination in an air lock of a two part valve opening in the air lock,
closing against a seat on the inner side of the air lock, a central opening in the
valve and stuffing box to close the same, substantially as specified.
5. The combination in an air lock of a two part valve, the trunnions of each part
held in arms ff on a shaft and each part provided with an arm h having a pin i and
the groove to adjust the surface of the valve part to the valve seat when closed,
and to turn it away when open, substantially as specified.
6. The combination in an air lock of a two part valve each part held in arms ff
on a shaft passing through the shell of the air lock, and each part free to turn in
the arms to adjust itself to the valve seat and the valve seat on the inner side of
the air lock, substantially as specified.
7. The combination in an air lock of two valves, one provided with a rope
opening at the centre, and each closing against a valve seat on the side against
which the air pressure is, so as to be pressed to its seat by the air pressure
substantially as specified.
8. The combination in an air lock of an outer valve made in two parts to close
around and open from a central cable and an inner valve, substantially as
specified.
9. The combination in an air lock of a valve seat and concave valve, having
hangers attached by which it is suspended on studs, distant from the valve seat
about one-half the width of the valve, and levers attached to the hangers by
floating links, substantially as specified.
10. The combination in an air lock of a valve seat and concave valve attached
by hangers to the seat at a point above the seat nearly equal to one half the width
of the seat, by studs and slots, with levers and floating links, substantially as
specified.
11. The combination in an air lock of an outer shell and inner shell provided
with a valve seat and concave valve attached by hangers to the seat at a point
above the seat nearly equal to one half the width of the valve, with levers attached
to them by floating links, substantially as specified.
Dated this 27th day of January 1894.
SYDNEY PITT.