AN EXPANSION VALVE WITH SELF-ACTING VALVE MOTION
Year: 1871

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes
and Son, Patent Agents, 123, Chancery Lane, London, for the
Invention of "AN EXPANSION VALVE WITH SELF-ACTING VALVE MOTION."
-A communication from abroad by François Windhausen, of
Brunswick, North Germany.
Sealed the 5th March 1872, and dated the 6th September 1871.
PROVISIONAL SPECIFICATION left by the said Edward Thomas
Hughes at the Office of the Commissioners of Patents, with his
Petition, on the 6th September 1871.
I, EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent
Agents, 123, Chancery Lane, London, do hereby declare the nature
of the said Invention for "AN EXPANSION VALVE WITH SELF-ACTING VALVE
MOTION," a communication to me from abroad by François Windhausen,
of Brunswick, North Germany, to be as follows :—
In one arrangement in which the expansion valve is worked by a
direct valve motion the valve is cast or connected to a tube which

page_text: passes through the valve box, and in this tube there is a rod having its
lower end reaching into the cylinder where the expansion is to take
place. The upper end of the rod is connected to a small piston in a
cylinder cast to the cover of the valve box, and the inside of this
cylinder communicates by a passage having two entrances, one being
shut as required by a small spherical valve and the other more or less
closed by a cone worked by a screw, and the required position of the
piston is determined by a regulating nut at the upper end of the piston
rod. In the interior of the valve box there is a short cylinder, also cast
to the cover of the valve box, and in this cylinder is placed the
expansion valve, the interior of the cylinder communicating with the
interior of the valve box by means of an opening having a clack and
another opening having a cone and screw, the first opening being closed
periodically by the clack and the second more or less by the cone.
When this apparatus is connected to one end of the cylinder of an air
expansion engine the main piston in the cylinder as it advances towards
the apparatus pushes the rod and small piston backwards, and thereby
the pressure of the small piston on the expansion valve is taken off, and
as the main piston is arriving nearly at the end of its stroke it meets a
projecting end of the valve tube and opens the valve, whereby the space
between the piston and the cylinder cover is filled with air of the same
pressure as that delivered to the valve box. The valve now opens self-
actingly with an over pressure corresponding with the area of the valve
tube, whilst the air in the valve cylinder escapes by the opening of
the clack into the valve box. At the return stroke of the main
piston the small piston acts upon the valve tube and closes the
valve as soon as the main piston is clear of the rod of the small
piston, and thus the main cylinder is filled with air of full pressure,
at least as far as the rod reaches into the, cylinder, and by turning
the screws and cones before mentioned the speed of the small piston
may be increased or retarded, and the air supplied to the main cylinder
more or less quickly.
:
When this apparatus is applied to each end of the cylinder of a steam
engine the steam passes from the steam chest through the ports and
passages into the valve boxes containing the expansion valves, which
work for the admission of steam to the required extent in the same
manner as described for the air engine. The regulating cones may
be made without the screws and be worked by the governor of the steam.

page_text: engine, so that an expansion of steam may be obtained corresponding to
the work required, and for greater security the slide valve has such a lap
that the inlet passages are closed before the eduction or outlet passages
are opened. In non-condensing engines I use a small valve adjusted by
a screw to allow a temporary supply or expansion of steam in case the
regulating nut on the rod of the small piston should not be in its proper
working position.
In any other arrangement I use an expansion valve adapted for double
seatings, and through the valve there is a central rod having its lower
end entering the cylinder of the engine the required distance for the
main piston to act upon it at nearly the end of its stroke. The top of
the rod is in contact with a lever in connection with the rod of the small
piston before described, and the bottom of this rod extends into the main
cylinder the depth that the air or steam is to be supplied at the same
pressure as in the valve box. In some cases it may be desirable to move
the small piston by a lever and weight, and then it is necessary that the
regulating cone and clack of the valve box can be adjusted from the
outside.
1
For extremely low temperatures I prefer to make that part of the
expansion valve where it rests on its seating of soft copper with a sharp
edge, but with moderate temperature and high pressure I employ
a valve which before it meets the seat strikes on a ring of india-rubber
cemented to the side or body of the seat, by which arrangement the
heavy striking or hammering of the valve is prevented.
5 SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Thomas Hughes in the Great Seal Patent
Office on the 5th March 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents,
0 123, Chancery Lanc, London, send greeting.
-
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of September, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give

page_text: a screw. In the interior of the valve chest there is a short cylinder E.,
also cast to the cover E,, the under side of the cylinder being opened and
closed by the piston-like valve A. The interior of this cylinder E, com--
municates with the valve chest through two passages H₁,
T₁, the passage
T, being closed periodically by the clack T, and the passage H₁ closed
more or less by the cone H worked by a screw.
The way in which the valve is applied to air and steam expansion
engines is shewn in Figs. 6 and 8b., Fig. 6 being a section of an air
engine, and Fig. 8b. a steam engine. In Fig. 6, if the piston B travels in.
the direction of the arrow 1 it pushes the rod B and small piston.
backwards, and the pressure of the small piston C on the valve A is
taken off, and as the piston B arrives near the end of its stroke it meets-
the projecting end A, of the valve tube A whereby the space between.
the piston B and the cylinder cover is filled with air of the same
pressure as that delivered to the valve chest. The valve A now opens
self-actingly with an over pressure corresponding with the area of the
valve tube A, whilst the air in the cylinder E, above the valve A
escapes into the valve chest E by the opening of the clack T..
At the return stroke of the piston B in the direction of the arrow 2.
the small piston C follows onwards until the bottom of the nut.
D acts upon the valve tube A₁, and the still further movement of
the piston shuts the valve A as soon as the piston B is clear of the rod B,
and thus the main cylinder is filled with air at the full pressure, at least
as far as the rod B reaches into the cylinder, and by moving the cones F
and H backwards or forwards by means of the screws the motion of the
piston C and the valve A. may be increased or retarded, and more or less
air supplied to the main cylinder as may be required, and the supply of
air can also be regulated by screwing the nut D up or down, and the
expanded air is exhausted as usual through the valve P, which is opened
and shut by a suitable valve motion.
In Fig. 8b., representing the application of this apparatus to a steam
engine, the steam passes from the valve chest through the passage D in
the chest of the expansion valve, which works for the admission of steam.
at full pressure in the same manner as before described for the air
engine, whilst the steam is exhausted through a slide valve C worked
by an ordinary valve motion, the latter bringing the passages Q and
Q₁ alternately in connection with the exhaust passage O.
The
'

page_text: screw F, which effects a retarded movement of the small piston
C, may be a pivot passing through a stuffing box and moved by
the governor, so that an expansion of the steam may be obtained
corresponding with the amount of force required. This arrangement
is clearly seen in Fig. 8b., in which the pivots F are moved by the
governor R, and the levers S, S₁, are so moved that if the engine works
too slow the pivots more or less descend, if the engine works too
fast the pivots are more or less raised, and by these means the valves A,
there being a similar apparatus at each end, are more or less quickly
closed according to the amount of power required. For greater
security the slide valve C has such a lap or cover that the passages
D and D₁ are shut before the passages Q and Q are opened, so
that the entrance of steam is prevented in case either of the valves A
should not be completely shut.
In non-condensing steam engines, in order to expand the steam to
below the pressure of the atmosphere, I use the valve L, Fig. 8a., which
can be opened at any time by the screw M, this arrangement being
suitable in case the position of the regulating nut D, Figs. 1 and 8b., only
allowing so small a supply of steam that the latter cannot be expanded
below the atmospheric pressure, but for condensing engines the valve L
can be dispensed with.
Figs. 3 and 4 are cross sections, representing a modification of the
valve shewn in Fig. 1. In this case the valve A has double seats with a
central rod A, which passes through a stuffing box and has its lower end
in the cylinder in which the expansion is to take place, so that when the
piston meets the lower end of the rod the valve may be raised to the end
of its stroke in consequence of the over pressure in the interior. To
shut the valve there is a lever D₁, upon one end of which the small
piston C presses, the piston rod reaching more or less into the cylinder
according to the position in which the regulating nut D is placed. 3
The steam or compressed air enters the cylinder through the pipe E₁, and
the cylinder E in which the small piston C works can be constructed as
in Fig. 1 for retarding or increasing the speed of the piston.
In many cases it may be desirable to move the small piston C by
weights or by a lever worked by hand, instead of by the steam or 3
compressed air, and in this case the arrangement for retarding the speed
of the main piston is shown in Fig. 5. The cover has two openings

page_text: or passages, one of which is periodically closed by a valve M and the
other by the cone L, and at the raising of the piston C the atmospheric
air escapes through the valve M which is shut when the small piston
descends, and thus the air can only enter by the passage L; the opening
of which is regulated by the cone L, and by turning the screw of the
cone as required any retarded or accelerated movement of the small
piston C can be produced.
+
.
For extremely low temperatures it is preferable to make that part of
the expansion valve where it rests on its seating of soft copper with a
sharp edge, but with moderate temperature and high pressure I employ
a valve A, shewn in Fig. 9, which strikes before it meets its seat B upon
a ring of india-rubber, leather, or gutta percha cemented to the side
or body of the seat, by which arrangement the heavy striking or
hammering of the valve is prevented.
Having now described the nature and particulars of the said
Invention, and the manner in which the same is to be performed,
I desire it to be understood that I claim,-
First. The improved arrangements and combinations of apparatus for
producing different pressures of air or steam in a cylinder by the striking
of the piston on parts of the apparatus, the apparatus being worked
not only by hand but also in a self-acting manner by the governor
during the working of the engine.
And Secondly. The packing or leathering of the valve seating, as
all such improvements are herein described and illustrated in the
accompanying Sheet of Drawings.
In witness whereof, I, the said Edward Thomas Hughes, have
hereunto set my hand and seal, this Fifth day of March, in the
year of our Lord One thousand eight hundred and seventy-two.
E. T. HUGHES. (L.S.)