IMPROVEMENTS IN MEANS FOR WORKING THE SLIDE VALVES OF STEAM AND SIMILAR MOTIVE POWER ENGINES
Year: 1881

page_text: LETTERS PATENT to Henry Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for an
Invention of "IMPROVEMENTS IN MEANS FOR WORKING THE SLIDE VALVES
OF STEAM AND SIMILAR MOTIVE POWER ENGINES." A communication from
PROVISIONAL SPECIFICATION left by the said Henry Edward Newton at
the Office of the Commissioners of Patents on the 30th May 1881.
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN MEANS FOR WORKING
THE SLIDE VALVES OF STEAM AND SIMILAR MOTIVE POWER ENGINES." [A com-
munication from abroad by Adolphus Nathan, of Milan, in the Kingdom of
Italy.]
This Invention is more especially intended to apply to direct acting steam pumps
in which a slide valve is used to open and close the inlet and exhaust ports, and
the Invention consists in novel means for working the slide valve.
In applying the Invention to a direct acting steam pump, a steam cylinder and a
pump cylinder are placed at opposite ends of a bed plate, as in other forms of
direct acting steam pumps, such as Tangye's and Blake's. The steam cylinder may
be similar to those of ordinary slide-valve engines, except that instead of one port
for the discharge placed between the two ports for the admission of the steam, the
discharge ports, of which there will be two, are placed outside the two admission
ports. The slide valve will be of the double D shape.
By this arrangement the steam will enter behind the piston which is necessitated
by the slide valve moving in the same direction as the piston is travelling. To
ensure the slide valve moving the whole distance required to open and close the
ports at the end of each stroke of the piston, a portion of the slide valve rod is
removed, and in its place a casting forming at its two extremities two air cylinders
is provided. These cylinders are closed by covers which are fixed in the remaining
parts of the rod. In each cylinder is placed a piston, which pistons are connected

page_text: by a small rod, so that when one piston is pushed forward to compress the air in
one cylinder, the other is drawn back in the other cylinder, and uncovers a small
opening through which air can pass, and make good any loss occasioned by the
compression which had previously taken place in the same. The air pistons are
moved by an arm fixed on the main piston rod, and guided on a stay. On the end
of the arm are two buffers, and above these two small discs so arranged as to lift
catches which are intended to hold the air cylinders in position until the required
amount of compression is obtained. The buffers and the discs can be made to
project more or less as may be required; the former so as to vary the pressure of
the air, according to the pressure of the steam, the latter so as to get the full stroke at
different speeds without fear of the piston striking against the covers.
To ensure the
slide valve stopping in the proper positions, two stops are fixed on a portion of the
valve rod. The whole of this arrangement constitutes two air springs, the elastic
force of which can always be kept constant and of any given power.
The mode of working is very simple; when steam is allowed to enter into the
steam chest, the inlet is open to one side of the piston, while the outlet or discharge
is open in the other. As soon as the piston gets towards the end of the stroke, the
buffer on the arm of the piston rod presses against one of the air pistons, and
compresses the air in its air-cylinder until the disc raises the catch, when the air-
spring, being set at liberty, causes the slide valve to assume its second position so
as to change the direction of the steam and the steamn piston to perform the return
journey.
If desired the catches may be dispensed with, though it is not advisable so to
work.
It will be evident that instead of compressed air a vacuum may be employed to
work the slide valve, and the Invention is applicable to other motive power
besides steam, such as compressed air or water motors.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Edward Newton in the Great Seal Patent Office ou
the 29th November 1881.
"
HENRY EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. IMPROVEMENTS IN MEANS FOR WORKING
THE SLIDE VALVES OF STEAM AND SIMILAR MOTIVE POWER ENGINES." A com-
munication from abroad by Adolphus Nathan, of Milan, in the Kingdom of Italy.
This Invention is more especially intended to apply to direct acting steam pumps
in which a slide valve is used to open and close the inlet and exhaust ports to the
steam cylinder, and the Invention consists in novel means for working the slide
valve.
In applying the Invention to a direct acting steam pump, a steam cylinder and
a pump cylinder are placed at opposite ends of a bed plate, as in other forms of
direct acting steam pumps, such as Tangye's and Blake's.
In the accompanying Drawing, Fig. 1 shews in side elevation a direct acting
steam pump of this class with the improvements added thereto. In this Figure
the cover of the steam chest and the slide valve are removed; Fig. 2 is a plan view
partly in section, and Fig. 3 is a cross section on the line 1, 2, of Figures 1 and 2
looking towards the steam cylinder.
A is the steam cylinder, and B the pump cylinder; C is the piston rod, and D
the piston of the steam cylinder. The cylinder A instead of having only one
discharge port placed between the two admission ports, as in the ordinary slide
valve engines, is formed with two discharge ports a, a¹, which are placed one
immediately outside of the two admission ports b, b'. In other respects the steam
cylinder is similar to those of engines of the same class.
The slide valve E which is a double D valve of the usual construction, is placed
in, the steam chest F. The slide valve E moves in the same direction as the
piston D, and therefore the above or a similar arrangement of valve is necessary to
permit of steam passing from the steam chest to the back of the piston previous to
and during the return stroke of the piston.
To provide for moving the slide valve the distance required to open and close
the several ports at the end of each stroke of the piston, the central portion of the
slide valve rod E' is removed and replaced by a casting G, having at each end a
small cylinder H, H'. The outer ends of these cylinders H, H', are closed by
covers to which are secured the remaining portions of the rod E'.
In each of the cylinders H, H¹, is placed a piston H2, H3, which pistons are
connected together by a light rod c at such distance apart, that when one piston is
pushed forward to compress the air in its cylinder, the other piston is drawn back
in its cylinder so as to uncover a small opening d made in the side of the cylinder
through which air can enter to make good any loss which may have in any way.
occurred during the act of compressing the air in that cylinder.
This
The pistons H2, H3, are moved by means of an arm e fixed on and projecting.
laterally from the piston rod C (see Fig. 3). This arm e is further supported by
and slides on a stay rod f suitably placed parallel with the piston rod C and the
casting G, and it terminates in a sleeve that embraces the piston rod c.
sleeve is provided with buffers g, g', which as the arm moves backwards and
forwards with the piston rod C strike alternately against one or other of the
pistons H, H. Above the buffers g, g', and attached to a vertical piece h forming
part of the arm e, are two bowles i, ', which are so arranged as to lift catches j, J²,
placed one at either end of the casting G, and intended to prevent the end way
motion of the casting G, while the air in one or other of the cylinders H, H¹, is
receiving the regulated amount of compression. These catches are pivotted, the
one j to a bracket secured to the casting of the steam pump, and the other 1 to
the jacket of the steam cylinder.

page_text: The buffers g, g¹, and the bowles i, i, are made adjustable, so that they may
project more or less as may be required, the buffers to vary the pressure of the air
according to the pressure of the steam, and the bowles to get the full stroke at
different speeds without fear of the piston D striking against the covers of the
cylinder A.
In order to prevent the slide valve moving further than is necessary to open and
close the ports, suitable stops are placed on the valve rod.
It will be seen that the compressed air in the cylinders H, H¹, will constitute
two air springs, the elastic force of which can always be kept constant and at any
given power.
The mode of working is extremely simple. The steam admitted to the steam
chest passes through the inlet b to the back of the piston D, at the same time the
port b¹ in front of the piston is through the slide valve placed in connection with
the discharge port a¹³. When the piston D gets towards the end of the stroke, the
buffer on the arm e of the piston rod C presses against and moves the air
piston H which compresses the air in the air cylinder H. When the air has
received the regulated amount of compression, the bowle i is in the position to
raise the catch. So soon as this is effected the slide rod E' being released, it will
be caused by the impulse of the compressed air in the cylinder H to move its slide
valve into the second position, and change the direction of the steam supply.
The direction of motion of the piston rod C being now reversed, the buffer g¹ and
the bowle will now be brought into action, the one to compress through the
piston H³ the air in the cylinder H¹, and the other to release the catch j¹ in order
that the slide valve rod may receive an impulse in the opposite direction.
Under some circumstances it may be desirable to dispense with the use of the
catches j, j', but it is advisable to employ them where possible, otherwise some
difficulty may arise in starting the engine or when working at slow speed.
Instead of compressed air a vacuum may be employed to work the slide valve.
In this case the openings d will be closed, and openings provided with a small
clack valve opening outwards will be formed in the covers of the cylinders H, H¹.
The action of the pistons H' and H³ will be alternately reversed, thus the
piston H2 when acted on by the buffer g instead of as before compressing the air,
will expel it from the cylinder H, and will cause the piston H³ to create a vacuum
in cylinder H'; and when the catch jis raised, the valve rod E¹ will be forced
forward by the pressure of the external air upon the head of the cylinder H³, and
vice versu, when the direction of motion of the buffers is reversed.
It will be evident that the Invention is equally applicable to compressed air or
water or other fluid motor.
Having now described the nature of the Invention for "Improvements in Means
for Working the Slide Valves of Steam and similar Motive Power Engines," as
communicated to me from abroad, and explained the manner of carrying the same
into effect, I wish it to be understood that under the above in part recited Letters
Patent I claim,―
Working the slide valves of steam engines and similar motive power engines by
the pressure of air obtained and applied in the manner herein described with
reference to the accompanying Drawing.
In witness whereof, I, the said Henry Edward Newton, have hereunto set
my hand and seal, the 29th day of November, in the year of our Lord
One thousand eight hundred and eighty one.