Improvements in Apparatus for Controlling Pressure, Applicable to Transmitting and Indicating Orders or Directions, and also to Indicating the Speed of Rotating Shafts.
Year: 1887

page_text: Date of Application, 18th Mar., 1887
Complete Left, 17th Dec., 1887
Complete Accepted, 3rd Feb., 1888
Improvements in Apparatus for Controlling Pressure, Applicable
to Transmitting and Indicating Orders or Directions, and also
to Indicating the Speed of Rotating Shafts.
I, JOHN ISAAC THORNYCROFT, of Church Wharf, Chiswick, in the County of
Middlesex, a member of the firm of J. I. Thornycroft & Coy., Steam Yacht and
Launch Builders, do hereby declare the nature of this invention to be as follows:-
--
This invention has for object improvements in apparatus for controlling pressure,
applicable to transmitting and indicating orders or directions and also to indicating
the speed of rotating shafts. When the pressure to be controlled is less than that of
the atmosphere a cylinder or valve case is connected at one part to an apparatus
capable of exercising a constant exhausting action, at another part to the pipe or
vessel in which the pressure is to be controlled, and at a third part to the atmosphere.
The first and third connexions are each provided with a valve, the two valves being
on one spindle, and moving together. The third inlet or opening to the cylinder or
valve case is located in a piston or diaphragm subject to the control of a spring or
other force that can be adjusted. It is the power of this spring or force that
determines the pressure maintained in the cylinder or valve case, and in the pipe or
vessel connected with it; by adjustment of the spring or force the pressure can be
varied.
Assuming this spring or force (hereinafter called a spring) to have an initial tension
or compression and the exhausting apparatus to be set in action the air will he exhausted
from the valve case and its connexions until the atmospheric pressure on the piston or
diaphragm exceeds the power of the spring, when the piston or diaphragm (hereinafter
called the piston) will move forward carrying both valves with it, and will close the
opening leading to the exhausting apparatus. The cylinder or valve case is thus
sealed. If the power of the spring be then increased the piston will be drawn back
opening the valve to the exhausting apparatus which will increase the vacuum until
the valve closes again. On the other hand, if the power of the spring be decreased
the atmospheric pressure will force the piston further forward past its valve, and air
D

page_text: will flow into the cylinder or valve case until the pressure is raised to a point
corresponding to the power of the spring.
It will be evident that apparatus according to this invention can be readily
modified for pressures higher than that of the atmosphere, and fluids other than air.
In the specification of a former patent granted to me the 5th November 1885
No. 13412 I described a system of signalling on board ship by reducing or increasing
the air pressure in a pipe provided with one or more indicators or gauges. That
system may be very efficiently carried out by aid of controlling apparatus according
to this invention. The spring is then used in connexion with a finger or pointer
operated by the officer or person giving the orders. When the pointer is set to a
mark representing a given order, such as "full speed ahead," the pressure in the
cylinder or valve case and its connexions is brought to a point at which the hands of
the connected gauges or indicators will point to a corresponding indication. By a
duplicate apparatus the engineer or steersman can signify his comprehension of and
obedience to the order.
To arrest the attention of the person to whom the order is sent an audible signal
may be employed. An arrangement for this purpose comprises a piston or diaphragm
subject on one side to the pressure in the officer's tube, and on the other side to the
pressure in the repeating or return tube. The movement of this piston or diaphragm
is caused to operate a bell or make an electric contact in a bell circuit. In this
latter case the bell will continue to ring until the engineer or steersman-has repeated
the order. If there be no return or repeating tube one side of the diaphragm may
be connected to an air vessel coupled to the main tube through a fine leak hole.
Light springs are used to keep the diaphragm in the central position when the air
pressures are equal.
For indicating the speed of a rotating shaft the power of the spring is adjusted by
a body driven from the shaft and subjected to centrifugal force, or the spring may
be dispensed with and the centrifugal force be made to act directly on the piston.
This force will vary as the square of the number of rotations, and the receiving dials
must be marked in accordance with this law.
101
11007
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: Improvements in Apparatus for Controlling Pressure, Applicable
to Transmitting and Indicating Orders or Directions, and also to
Indicating the Speed of Rotating Shafts.
I, JOHN ISAAC THORNYCROFT, of Church Wharf, Chiswick, in the County of
Middlesex, a member of the firm of J. I. Thornycroft & Coy., Steam Yacht and
Launch Builders, 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 :-
This Invention has for object improvements in apparatus for controlling pressure,
applicable to transmitting and indicating orders or directions and also to indicating
the speed of rotating shafts. When the pressure to be controlled is less than that of
the atmosphere a cylinder or valve case is connected at one part to an apparatus
capable of exercising a constant exhausting action, at another part to the pipe or
vessel in which the pressure is to be controlled, and at a third part to the atmosphere.
The first and third connections are each provided with a valve, the two valves being
on one spindle, and moving together. The third inlet or opening to the cylinder
or valve case is located in a piston or diaphragm subject to the control of a spring or
other force that can be adjusted. It is the power of this spring or force that
determines the pressure maintained in the cylinder or valve case, and in the pipe or
vessel connected with it; by adjustment of the spring or force the pressure can be
varied.
Assuming this spring or force (hereinafter called a spring) to have an initial
tension or compression and the exhausting apparatus to be set in action the air will be
exhausted from the valve case and its connections until the atmospheric pressure on
the piston or diaphragm exceeds the power of the spring, when the piston or diaphragm
(bereainfter called the piston) will move forward carrying both valves with it, and
will close the opening leading to the exhausting apparatus. The cylinder or valve case
is thus sealed. If the power of the spring be then increased the piston will be
drawn back opening the valve to the exhausting apparatus which will increase the
vacuum until the valve closes again. On the other hand, if the power of the spring be
decreased the atmospheric pressure will force the piston further forward past its valve,
and air will flow into the cylinder or valve case until the pressure is raised to a point
corresponding to the power of the spring..
It will be evident that apparatus according to this invention can be readily modified
for pressures higher than that of the atmosphere, and fluids other than air.
In the Specification of a former patent granted to me the 5th November 1885
No. 13412 described a system of signalling on board ship by reducing or increasing
the air pressure in a pipe provided with one or more indicators or guages. That
system may be very efficiently carried out by aid of controlling apparatus according
to this invention. The spring is then used in connection with a finger or pointer
operated by the officer or person giving the orders. When the pointer is set to a
mark representing a given order, such as "full speed ahead," the pressure in the
cylinder or valve case and its connections is brought to a point at which the
hands of the connected gauges or indicators will point to a corresponding indication.

page_text: By a duplicate apparatus the engineer or steersman can signify his comprehension of
and obedience to the order.
To arrest the attention of the person to whom the order is sent an audible signal
may be employed. An arrangement for this purpose comprises a piston, a diaphragm
subject on one side to the pressure in the officer's tube, and on the other side to the
pressure in the repeating or return tube. The movement of this piston or diaphragm
is caused to operate a bell or make an electric contact in a bell circuit. In this latter
case the hell will continue to ring until the engineer or steersman has repeated the
order. If there be no return or repeating tube one side of the diaphragm may be
connected to an air vessel coupled to the main tube through a fine leak hole. Light
springs are used to keep the diaphragm in the central position when the air pressures
are equal.
For indicating the speed of a rotating shaft the power of the spring is adjusted by
a hody driven from the shaft and subjected to centrifugal force, or the spring may
be dispensed with and the centrifugal force be made to act directly on the piston.
This force will vary as the square of the number of rotations, and the receiving dials
must be marked in accordance with this law.
Referring to the accompanying illustrative drawings-
Fig. 1 is a front elevation of an apparatus for controlling pressure for the purpose
of transmitting signals according to this invention.
as
Fig. 2 is a vertical section of the same parallel to Fig. 1.
Fig. 3 is a horizontal section.
Figs. 4 and 5 shew details.
Within the frame of the apparatus there is a bored cylinder 1 within which there
works a valve case 2 which can he moved up and down in the cylinder by means of
a pinion 11 which gears with teeth or rings turned on the surface of the cylinder.
The pinion is rotated by an external handle 12 furnished with a pointer 13 and a stop
screw 14 (Fig. 4). The pointer moves over the dial of the instrument, which may be
divided or graduated according to the purpose to which the indicating apparatus is to
be put. In the case of an engine room telegraph the dial will bear such indications
stop," "ahead," "astern." The valve case 2 moves practically air tight in the
cylinder 1, and communicates at its upper end with the atmosphere through holes in
a cap or cover 3. At the lower end of the valve case is a stuffing box working
over a fixed tube 4 which communicates by means of a passage in the frame and a
pipe with one or more indicating dials. Within the pipe 4 is another pipe 5
communicating through the pipe 6 with an exhausting apparatus such as an air pump.
The entrance to the pipe 5 is commanded by a valve 7 which is mounted on the
same spindle as another valve 8. Before air can pass from the external atmosphere to
the air pump by the pipe 6 it must pass both the valves 7 and 8 which are never
opened together. The latter valve has its seat in a piston or hollow plunger 9, which
is connected with the valve case 2 by a spring 10. It is evident that if the valve
case were moved downwards by the pinion, the parts being in the position shewn in
Fig. 2, the valve 8 would leave its seat, or rather the seat would leave the valve, unless
the spring kept the plunger 9 stationary. On the other hand if the valve case were
moved upwards the valve 7 would be lifted off its seat unless the spring kept the
plunger stationary.
To explain the operation of the apparatus let it be assumed that with the parts in
the position shewn in Fig. 2 there exists a partial vacuum in the pipes 6 and 5, and
under the piston 9. The upper side of this piston is exposed to the pressure of the
atmosphere and the excess of pressure on that side is balanced by the spring 10 which
is in compression.
"
Now let the pinion 11 be turned until the pointer 13 is opposite the word "ahead
The valve case 2 will rise carrying with it the piston 9 and the two valves 7 and 8.
The lifting of the valve 7 will put the pipes 4 and 5 into communication, and air will
be drawn out of the former and out of the pipe and gauges with which it is connected,
and will pass away by the tube to the exhausting apparatus. As this process
proceeds the pressure under the piston 9 will be reduced, and the piston will gradually

page_text: wescend compressing the spring 10, and lowering the valve 7 until it again comes to
its seat. When this happens the exhaustion of the pipe ceases and there exists a
constant partial vacuum in the pipe and in its connections. This partial vacuum
may be employed to operate indicating dials which when exhausted to this amount
will have their pointers opposite the same indication as the pointer 13; in the case
above assumed the indication is "ahead."
If the valve case be depressed, instead of being raised as just explained, the
valve 8 will leave its seat. The atmosphere will rush through the valve seat impairing
the partial vacuum below the piston and the pipe 4 and its connections.
piston will then rise, owing to the increase of pressure below it, and the valve 8 will
The
close.
It is therefore evident that for each position of the valve case there is a corresponding
degree of vacuum at which both the valves 7 and 8 will be shut.
In the arrangement shewn in these views the adjustment of the spring takes place
as the result of the motion of the piston, but it is evident that it might be effected
directly from the pinion 1.1. If the cylinder 2 were divided into two parts, the upper
part being fixed in the case 1, and the lower part being moveable, then the pinion 11
would act directly on the spring 10, and the piston 9 would move within its cylinder,
and not be moved with the cylinder. In lieu of using a piston, a diaphragm secured
at its circumference may be used.
To call the attention of the person to whom the signal or indication is sent the
apparatus shewn in Fig. 6 may be employed. This consists of a case 14 A divided
into two portions by a flexible diaphragm 15, which is normally kept in its mid
position by two springs 16. 16. Two tubes 17. 18. enter the case 14 A one at each
side of the diaphragm. One of these tubes is in connection with the tube 4* (Fig. 2),
while the other is in connection with the corresponding tube of a similar apparatus
to that shewn in Figs. 1 and 2, and which is designed to be used as a repeating
apparatus by the person receiving the order.
Should a change of pressure occur in the tube 17, the diaphragm will be moved
one way or the other, and the spindle attached to it will make contact with one of
the brass springs 20, 20, and will complete an electric circuit in which is a signalling
device, such as a bell. This device will continue to sound until the pressure in the
pipe 18 is made, by the action of giving the return signal, to correspond with the
pressure in the pipe 17.
If apparatus according to this invention be applied as an engine room telegraph it
may happen that when the engine is stationary there will be no exhausting appliance
in operation. For such a case there are provided (Figs. 2 & 5) two electric bell
calls 21, 21, each provided with a push or key, the one serving to convey the signal
"Go ahead slowly" and the other "Go astern slowly "As soon as the engine starts
the exhausting device comes into operation, and any required signal within the range
of the apparatus may be sent.
Figs. 7 to 10 shew apparatus according to this invention arranged as a ship's
telegraph, and applicable for transmitting orders to the engine room, the steering
house, or other part of the vessel. The parts corresponding to those in Figs. 1 to 5
are correspondingly numbered. The apparatus for controlling pressure is mounted
on the top of a pillar 22, and on the capital of this pillar there are three dials, the
one of which indicates to the officer the signal he has sent, the second receives and
shows the return or reply signal while the third is a speed indicator as will be
explained later.
In the arrangement herein shewn the valve case 2 is inoved end wise by a modified
arrangement in which a screw thread performs the office of the rack and pinion 11
described with reference to Fig. 2. The handle 12 is connected to a ring 23
surrounding the valve case 2. A groove 24 is cut lengthwise in the valve case and
in this groove there works a key in the ring 23. Consequently when the ring is
rotated by its handle the valve case is rotated also, but it is free to rise or descend by
reason of the screw thread 25 which engages with a corresponding thread in the
cylinder surrounding it. There need be no pointer to the dial, (though one is

page_text: shown) the officer watching the tell tale gauge to know how far he should move the
handle.
Between the pipe and the pipe 4* leading to the various indicating apparatus
there is interposed a cock 25^, provided with an elongated stem or spindle which
rises through the top plate of the pillar and carries a handle 26. On the valve spindle
there is a flange 27 and between it and the handle is a collar 28. The collar 28
works in a groove in the ring 23. The flange 27 is cut away where it bears against
the ring which has two circular recesses 29, 29, formed in it. With the parts in the
positions shown the handle 12 can be moved, while the handle 26 is locked. When
either of the recesses 29, 29, are opposite the valve spindle the handle 26 can be
turned to cut off the connection between the indicating dial and the pipe 4. The
action of turning the tap or cock locks the handle 12, and the apparatus is so arranged
that under these circumstances the indicators point, in the case of an engine room
telegraph, to "Stand by ahead" or "Stand by astern." The officer can then leave
this instrument and use any other which may be fitted in a different position in the
ship. The pedestal or pillar may contain a light to illumine the dials at night.
Fig. 10 shows the connection of the electric conductors to the pedestal or pillar.
If the pressure to be controlled is greater than that which has access to the upper
side of the piston the arrangement of the valves 7 and 8 will need to be reversed the
valve 7 opening when the piston or diaphragm descends and the valve 8 opening
when the piston or diaphragmn rises. The combined valves will then need to have
their weight supported by a spring or equivalent contrivance when the apparatus is
arranged vertically as in Fig. 2, and the spring 10 will be in tension.
Figs. 11 and 12 show in section and elevation apparatus for controlling pressure
applied to indicate the speed of rotating shafts. Parts corresponding to those
appearing on sheet I are similarly numbered.
Within a fixed bearing 30 there rotates a vertical spindle 31 driven by a band
which partly encircles the pulley 32. At the top of the spindle is a cup or dish 33
in which lies a body 2* which corresponds to the cylinder 2 described with reference
16 Fig. 2, but which is unprovided with means for varying its position. Within this
body there is a bored cavity in which there works the plunger 9, capable of endwise
motion. A valve seat is formed in this plunger for the valve 8 which is connected
by a stem or spindle to the valve 7.
The apparatus has three connections; the opening 3 admits the atmosphere to the
interior of the plunger 9; the pipe 4 is connected to the external tube on which the
indicators are fixed, while the outlet 6 is connected to exhausting apparatus. Owing
to the fact that the piston and valves are carried in a rotating body, while the con-
nections to the external pipes are stationary the passages are not quite as direct as
those shewn in Fig. 2. They can, however, be easily followed on the drawings, and
will be most readily understood by tracing the movements of the air within them.
Let it be assumed that the spindle is rotating with a uniform velocity, and thai the
exhausting apparatus is in operation. The plunger 9 will be urged outwards by
centrifugal force and this force will be balanced by the excess of pressure on its outer
end over that on its inner end. Any outwardly acting centrifugal force in the
coupled valves 7 and 8 is resisted by the spring 34. Now should the speed of
rotation of the spindle increase, the piston will move outwards and the valve 7 will
leave its seat. Air will then be drawn from the external indicator tube, through the
tubes 4 and 4, past the valve 7 into the tube 5 and down the annular passage in the
spindle to the chamber at the bottom of it, and thence by the outlet 6 to the exhausting
apparatus. When the pressure has been reduced sufficiently to balance the centri
fugal force of the plunger the latter returns to its former position and the valve 7
closes the tube 5.
Should the speed of the shaft be decreased the plunger will move inwards, and the
external air will pass the valve 8 until the partial vacuum existing below the plunger
and in the indicator pipe is so far reduced that the plunger moves back to its norinal
position, and closes the valve 8.
Leather packing rings form a convenient means of rendering the various joints

page_text: air-tight. Such rings are shown on the piston, at the top of the tube 4, also at the
bottom of it and of the spindle 31. This latter ring is held in place by a stuffing
box 35 held up by a spring 36. The stuffing box is kept from rotating by a pin
which engages in a vertical groove in the bracket 30. The body 2* is not fixed in
the cup 33; it is made to fit air-tight around the passagos in the spindle by the
packing ring 37.
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 for controlling pressure a piston or diaphragm subject on one
side to a constant fluid pressure (such as the atmosphere) and on the other side
to the pressure to be controlled, and normally held in equilibrium by means of an
adjustable spring, in combination with two valves one of those being seated in
the said piston or diaphragm and the other arranged so that it can be caused to
open or close communication with a source of pressure (or vacuum) substantially
as described.
2. In apparatus for controlling pressure a moveable valve case containing a piston
or diaphragm in which is seated a valve, the said piston or diaphragm being subject
on one side to a constant fluid pressure and on the other side to a pressure that
is to be controlled, in combination with an adjustable spring by which the piston
or diaphragm is brought into equilibrium substantially as described.
3. In apparatas for controlling pressure the combination with a moveable valve
case containing a piston or diaphragm subject to a constant fluid pressure, to a
pressure to be controlled and to the pressure of an adjustable spring, of two
valves and a handle, or lever by which the valve case is moved substantially as
described.
4. In apparatus for controlling pressure two valves connected together, the one
taking into a fixed seat and the other into a seat in a piston or diaphragm that
can be moved by hand, the arrangement being such that when the piston or
diaphragm is moved in one direction the one valve will open communication between
a source of pressure or vacuum and the vessel or pipe in which the pressure is to be
controlled, and when the piston or diaphragm is moved in the opposite direction
the other valve will open communication between a source of constant pressure
(such as the atmosphere) and the said vessel or pipe in which pressure is to be
controlled.
5. My improved apparatus for controlling pressure substantially as described
with reference respectively to Figs. 1 to 4 and to Figs. 7 to 9 of the drawings.
6. In apparatus for indicating the speed of rotating shafts a piston or diaphragm
subject to a constant fluid pressure, to a fluid pressure that can be controlled or
varied, and to a pressure or force due to centrifugal action, the arrangement being
such that the variable fluid pressure will automatically adjust itself to variation in the
centrifugal force substantially as described.
7. My improved apparatus for indicating the speed of rotating shafts substantially
as described with reference to Figs. 11 and 12 of the drawings annexed.
8. In combination with apparatus for transmitting signals by variations in pressure
the electric contact-making device substantially as hereinabove described with reference
to and shown in Fig. 6 of the drawings annexed.
Jated the 17th day of Lacomben 1007
17th of December 1997
JOHN I. THORNYCROFT.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C.,
Applicant's Agent.