IMPROVEMENTS IN STEAM ENGINES
Year: 1879

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the
City of London, Patent Agent and Consulting Engineer, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES." A cominunication from abroad by
Theodore Waag, of Lille, France.
aled the 1st July 1879, and dated the 10th January 1879.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 10th January 1879.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN STEAM ENGINES." [A com-
munication from abroad by Theodore Waag, of Lille, France.]
This Invention consists of improvements in steam engines, and its object is a
mode of varying or regulating the working or expansion by means of the engine
governor.
At each end of the engine cylinder is a steam chest or valve box; these two
boxos are in communication by a pipe, in the middle of which is the steain supply
cock. The faces or beds in which the inlet ports are formed are cast with or fixed
to the cylinder. These ports lead to collecting channels, which communicate with
the two ends of the cylinder. Below the said faces or beds and in the said channels
are the exhaust slide valves, which allow the steam to exhaust into pipes. The
faces of the exhaust slide valves are situated a little below the lower line of the
cylinder, which ensures the constant discharge of the water resulting from conden-
sation, and avoids the risks of having water in the engine without requiring any
blow-off pipe. Injurious spaces are by this arrangement reduced to their
minimum.
The four slide valves are plane, with single or multiple ports.
The distribution is produced by means of an excentric, the rod of which gives
oscillating motion to a lever on an axis at one end thereof. To this lever are jointed
an upper and a lower T piece. Through the lower T piece pass two rods, which
open and close the exhaust valves, these valves being capable of regulation by means
of nuts on the said rods. The rod of the back exhaust valve passes through the
front valve box without being in communication with the steam, and it is only
upon its entering the rear valve box that a stuffing box is useful. The rod of the
frout exhaust valve passes through a stuffing box on entering the front valve box,
and does not go beyond this box.

page_text: To the upper T piece are fixed two rods; one of these rods commands the
opening of the front inlet valve in the one direction, and the other rod the opening
of the back inlet valve in the other direction. These rods are sometimes inde-
pendent of the rods of the inlet valves, and sometimes connected to them by means
of an engaging apparatus, the release of which is varied by the variation of the
actions produced by the engine governor.
The apparatus just referred to works as follows:-To the frame of the engine is
fixed a support, in the upper part of which slides a block whose acting face is
inclined or curved, and whose height varies with the governor. In the lower part
of the said support slides a shoe, to which is fixed the rod of the back inlet valve,
and to this shoe are jointed an engaging lever and a catch lever. In its normal
position the catch lever, being acted upon by a spring, prevents the engaging lever
rising. On the rod, which is fixed to the upper T piece as before mentioned, is
fixed a tappet with an inclined face. If this rod moves in one direction the inclined
face of the tappet meets a tappet attached to the engaging lever and tends to raise
this lever, which is however prevented by the catch lever. The said rod therefore
draws into its movement the shoe and all the parts which it carries until a projec-
tion on the catch lever comes against tho block before mentioned, which causing it
to move on its axis will release the engaging lever; this will rise and break the
connection between the rod attached to the T piece and the valve rod, so that if a
spring then acts on this valve rod to return it to its point of departure, nothing will
provent it, and the introduction of the steam will be at once stopped. A steam
spring or a metallic spring can be employed to effect this shutting off of the steam.
The block before mentioned carries a finger whose object is to prevent the admission
of steam in case the working by means of the governor should be accidentally
interrupted; in fact the fall of the governor balls would bring the block to its
highest position, which would place the finger opposite a spur situated behind the
projection on the catch lever, and in this case the shoo would never be moved, and
consequently the inlet valve which is closed would never be displaced, and therefore
the steam would not enter the cylinder.
To avoid the concussion of the shoe against the support when it is freed by the
catch lever and pulled back by the spring, leather or caoutchouc is placed between
the two parts.
I have described the engaging apparatus of the back inlet valve. For the front
valve an exactly similar apparatus works in the same manner in the opposite direc-
tion. In this way the single excentric which operates the distribution opens the
one valve in the forward movement and the other in the backward movement. This
excentric can be fitted with an apparatus for throwing in and out of gear, so that
the direction of rotation can be altered while the engine is going; any ordinary or
suitable arrangement can be fitted for this purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the 5th
July 1879.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN STEAM ENGINES." (A com-
munication from abroad by Theodore Wang, of Lille, France)
This Invention consists of improvements in steam engines, and its object is a
modo of varying or regulating the working or expansion by means of the engine
governor.
Figure 1, of the annexed Drawings represents an elevation partly in section of
the improved engine, and Figure 2 is a section through the line 1, 2, 3, 4, of
Figure 1.
At each end of the engine cylinder C is a steam chest or valve box. These two
boxes, marked in the Drawing B and B' respectively, are in communication by a
pipe D, in the middle of which is the steam supply cock E. The faces or beds F
and F, in which the inlet ports G, G, G, G', G₁, G', are formed, are cast with or
fixed to the cylinder. These ports lead to collecting channels H and H, which
communicato with the two ends of the cylinder. Below the faces or beds F, F,
and in the said channels H, H', are the exhaust slide valves I and I', which allow
the steam to exhaust into pipes K and K. The faces J and J¹ of the exhaust
slide valves are situated a little below the lower line of the cylinder, which ensures
the constant discharge of the water resulting from condensation, and avoids the
risks of having water in the engine, without requiring any blow off pipe. Injurious
spaces are by this arrangement reduced to their minimum.
The four slide valves are plane, with single or multiple ports.
The distribution is produced by means of an excentric, the rod L of which gives
oscillating motion to a lever M on an axis at O. To this lever are jointed two T
pieces N and P. Through the lower T piece P pass two rods R and R', which
open and close the exhaust valves I, 1', these valves being capable of regulation by
means of nuts a, a'. The rod R¹ of the back exhaust valve passes through the
front valve box without being in communication with the steam, and it is only
upon its entering the rear valve box that a stuffing box is useful. The rod R of
the front exhaust valve passes through a stuffing box on entering the front valve
box, and does not go beyond this box.
To the upper T piece N are fixed two rods Q and Q' One of these rods Q
commands the opening of the front inlet valve in the direction of the arrow f, and
the other rod Q1, the opening of the back inlet valve in the direction of the arrow f.
These rods are sometimes independent of the rods S and S¹ of the inlet valves, and
sometimes connected to them by means of an engaging apparatus, the release of
which is varied by the variation of the actions produced by the engine governor.
The apparatus just referred to is represented on a larger scale in the detail views,
Figures 3 to 6, and works as follows:-To the frame of the engine is fixed a
support T, in the upper part of which slides a block U' whose acting face is inclined
or curved, and whose height varies with the governor. In the lower part of the
support T slides a shoo V₁, to which is fixed the rod S' of the back inlet valve, and
to this shoe are jointed an engaging lever el and a catch lever g'. In its normal
position (represented in full lines) the catch lever g₁ being acted upon by a spring
P', prevents the engaging lever e rising. On the rod Q is fixed a tappet b', with
an inclined face c¹. If this rod Q' moves in the direction of the arrow f¹, the
inclined face of the tappet b' meets a tappet d' attached to the engaging lever and
tends to raise this lever, which is however prevented by the catch lever gl. The
rod Q, therefore draws into its movement the shoe V and all the parts, which it
carries until a projection A¹ on the catch lever g¹ comes against the block U₁, which
causing it to move into the position indicated in dotted lines will release the lover

page_text: e; this will rise and break the connection between the rod Q₁and the valve rod
S', so that if a spring then acts on this rod S¹ to return it to its point of departure,
nothing will prevent it, and the introduction of the steam will be at onco stopped.
A steam spring or a metallic spring can be employed to effect this shutting off of
the steam. The block U carries a finger i, whose object is to prevent the
admission of steam in case the working by means of the governor should be
accidentally interrupted; in fact the fall of the governor balls would bring the
block U' to its highest position, which would place the finger i opposite a spur k¹
situated behind the projection ' on the catch lever; and in this case the shoe V¹
would never be moved, and consequently the inlet valve which is closed would
nover be displaced, and therefore the steam would not enter the cylinder.
To avoid the concussion of the shoe V₁ against the support T when it is freed by
the catch lever and pulled back by the spring, leather or caoutchouc is placed
between the two parts.
I have described the engaging apparatus of the back inlet valve, as represented
in Figure 3. For the front valve an exactly similar apparatus, represented in
Figuro 5, works in the same manner in the opposite direction. In this way the
single excentric which operates the distribution opens the one valve in the forward
movement and the other in the backward movement. This eccentric can be fitted
with an apparatus for throwing in and out of gear, so that the direction of rotation
can be altered while the engine is going; any ordinary or suitable arrangement
can be fitted for this purpose.
And having now described the nature of the said Invention, and in what manner
the same is to be performed, I declare that I claim.
The mode or mechanism, substantially as herein before described and represented
in the annexed Drawings for varying or regulating the working or expansion in
steam engines.
In witness whereof, I the said John Clayton Mewburn, have hereunto set
my hand and scal, this Second day of July, One thousand eight hundred
and seventy nine.