A. VALVE FOR THE ADMISSION DISTRIBUTION EXHAUST AND CUT OFF of Steam SUPPLIED TO THE CYLINDER OF A STEAM ENGINE
Year: 1884

page_text: BENJAMIN GREEN MARTIN Engineer 60 South Mall in the City of Cork Ireland
do hereby declare the nature of my Invention for A. VALVE FOR THE ADMISSION
DISTRIBUTION EXHAUST AND CUT OFF of Steam SUPPLIED TO THE CYLINDER
OF A STEAM ENGINE to be as follows:-
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This valve consists of two cylinders the outer one being bored to receive the
inner one which is turned up on the outside to fit the bore of the outer one
accurately.
Figure 1 is an external view of the outer cylinder with a steam case I containing
three steam chambers N° 1. 2 & 3. In this casing are ports A. A one or more at
cach end XX for the admission and exit of the steam to and from the steam engine
cylinder and an opening in the centre F for the exhaust steam.
This steam case and outer cylinder can be cast either together, or separately,
and can be attached to any steam engine cylinder. The two ends of this outer
cylinder are fitted with detachable heads one of which has a stuffing box and
gland and on one, or both, of these ends is a steam pipe connexion N.
Figure 4, is a sectional view of the inner cylinder and which inner cylinder
forms the valve proper, the outer cylinder being really the valve case.
This inner
cylinder has three steam chambers D D E of which D D are the live steam
chambers and the centre chamber E is for the exhaust steam.
When only one steam pipe is used, or connected, to the outer cylinder Fig. 1,
a steam pipe C passes from one live steam chamber to the other through the
exhaust steam chamber E, this pipe allows the steam to pass from one live steam
chamber to the other when the steam is only fed into one chamber as is the case
when only one steam pipe connexion is used on the outer cylinder Fig. 1 and
consequently the pressure of steam in each live steam chamber is the same as it
would be if both ends of the outer cylinder were in communication with the steam
pipe, or boiler. The two live steam chambers have sloping or straight ports, in
each, corresponding with two, or more, sloping or straight ports in the outer
cylinder. Fig. 1. and the centre or exhaust chamber has oblong or square ports BB
for the exhaust steam to pass away through from chambers 1 & 3, Fig. 1. into the
exhaust steam chamber E and thence through ports M M M & into the chamber
in the casing attached to outer cylinder marked N° 2 and then away by pipe D,
FA

page_text: Figures 1 & 2. This inner cylinder (Fig. 4) has partitions L in the shape of the
letter Zone between each live steam chamber and the exhaust chamber.
A crosshead K is cast in, or fitted to, one end of the inner cylinder to which a
rod J is attached and this rod passes through the stuffing box G Figures 5 & 6.
This inner cylinder (Fig. 4) may have a packing ring or rings, or V groove or
grooves between each live steam compartment and the exhaust compartment and
also between each live steam port and exhaust port to prevent steam leaking from
one to the other.
Figure 3 is a longitudinal section of the inner cylinder Figure 4.
Figure 6 is an arrangement of gearing communicating to the rod J and thereby
to the inner cylinder (Fig. 4) a rotary, or partial rotary, or oscillating movement,
whereby steam is admitted to and exhausted from the steam engine cylinder and
at the same time allows the rod J to move longitudinally through the stuffing box
and thereby giving the inner cylinder a movement transverse to the ports in the
outer cylinder for the purpose of altering the point of cut off of the steam and the
ratio of expansion. This longitudinal movement being actuated and controlled by
the governor. or by hand gear.
Figure 7 is an end section of the inner cylinder Fig. 4 D is the live steam
chamber, E is the exhaust steam chamber. O the steam pipe from one live steam
chamber to the other. A* A* are the two, or more, steam ports.
The steam chamber at one end of the inner cylinder being in open commu-
nication with the chamber at the other end. through the pipe C. the steam pressure
in each live steam chamber is equal and consequently the pressure on each of the
partitions which separate the live steam chambers from the exhaust chamber is
also equal and being in opposite directions the inner cylinder, or valve, is balanced.
Dated this Third day of March 1884.

page_text: I BENJAMIN GREEN MARTIN of 60 South Mall in the City of Cork, Ireland
Engineer do hereby declare the nature of my Invention for A VALVE FOR THE
ADMISSION, DISTRIBUTION, EXHAUST, AND CUT-OFF OF STEAM SUPPLIED TO THE
CYLINDER OF A STEAM ENGINE and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
The object of the Invention is to increase the efficiency of equilibrium valves of
steam engines by constructing the improved valve so that the steam may act with
equal pressure on opposite sides of that valve enabling that valve to float or move
on equal balance of steam pressure and thereby reduce frictional resistance.
The improved valve consists of two cylinders, an outer one and an inner one,
the outer one being bored to receive the inner one, the inner tube is turned up on
the outside so as to accurately fit the bore of the outer cylinder at those parts
where the steam and exhaust ports are situated and work.
Figure 1 is an underside view and
Figure 2 is an external view of the outer cylinder with ports A* A* one, or
more, at each end opening into two chambers N° 1 and 3 which are placed in
connection with the passages leading to the two ends of the cylinder of the steam
engine and also having an exhaust port F opening into a chamber N° 2 which is
connected with the passage leading to the exhaust pipe O. The case I containing
the three chambers N° 1, 2, & 3 may be cast together with the outer cylinder of
valve or with the steam engine cylinder; or separately from both, as may be
found most convenient for attaching the improved valve to old, or existing, steam
engines. The two ends of this outer cylinder shewn respectively by Figures 5
and 6 are fitted with detachable heads X X. On either, or both, of these heads is
provided a stuffing box and gland and also a steam pipe connection N. Figure 5.
Figure 4 is a sectional view of the inner cylinder (which forms the valve proper,)
and of the outer cylinder (which is really the valve case.)
Figure 4 shews by diagram the external surface of the inner valve laid out.
This inner cylinder bas three steam compartments D D E of which D D are the
live steam compartiments and the centre compartment E is for the exhaust steam.
These compartments or chambers for steam are separated by partitions L L of
suitable form which may be sloping, stepped, straight, or other suitable shape or
form according to the shape and position of the ports used.
The two live steam compartments D D have suitably shaped ports A A which
may be of a rectangular, rhomboidal or triangular figure for the admission and cut
off of steam to the steam engine cylinder through the ports A* in the outer
cylinder and chambers 1 and 3 in the case attached to it and the centre or exhaust
compartment E has suitably formed ports BB which may be oblong, square,
sloping or otherwise adapted to the parts they operate with for the exhaust steam
to pass away through from chambers 1 and 3 of the case or outer cylinder into the
exhaust steam chamber E, and thence through ports M. M into the chamber N° 2 in
the case or outer cylinder and then away to a condenser, or the atmosphere by
pipe o Figures 1 and 2.
A crosshead K is cast in, or fitted to, one or both ends of the inner cylinder to
which a rod J is attached and this rod passes through the stuffing box G.
When only one steam pipe is used or connected to the outer cylinder (Figure 1)
a steam pipe C passes from one live steam compartiment to the other through the
exhaust steam compartment E this pipe C allows the steam to pass from one live
steam compartment to the other where steam is fed into one compartment only, as

page_text: is the case when only one steam pipe connection is used on the outer cylinder
(Figure 1) and consequently the pressure of steam in each live steam compartment
is the same as it would be if both ends of the cylinders were in communication
with the steam pipe, or boiler, and consequently the pressure on each of the
partitions which separate the live steam compartments from the exhaust com-
partment is also equal and being in opposite directions the pressure of steam
upon the valve is balanced or the valve is in equilibrium.
The inner cylinder (Figure 4) may have a packing ring, or rings, a V groove,
or grooves, between each live steam compartment and the exhaust compartment
and also between each live steam port and exhaust port to prevent steam leaking
from one to the other.
Figure 3 is an external view and Figure 34 an end view of the inner cylinder
(Figure 4).
Figure 7 is an end section of the inner and outer cylinders (Figure 4) as already
stated. D is the live steam compartment. E is the exhaust steam compartment.
C the steam pipe from one live steam compartment to the other. A* A* are the
steam ports.
The motion to be communicated from the crank shaft of the steam engine to
the inner cylinder through the rod J may be a rotary, or an oscillatory or a
reciprocating movement according to the arrangement of the ports and the form of
ports adopted.
Gearing communicating to the rod J and thereby to the inner cylinder may give
a rotary movement whereby steam may be admitted to and be exhausted from
the steam engine cylinder and at the same time admit of the rod J moving
longitudinally through the stuffing box and thereby give the inner cylinder a
movement in a direction transverse to the ports in the outer cylinder for the
purpose of varying the point of cut off of the steam and the ratio of expansion.
This longitudinal movement being actuated and controlled by the governor, or by
hand gear.
Should an oscillating movement be perferred to a rotary one for the inner
cylinder, a like arrangement of cut off may be used the ports in the inner cylinder
being formed of a rhomboidal form instead of triangular such triangular form
being found well adapted when employing a rotary movement.
Having thus described and ascertained the nature of my said Invention and
in what manner the same is to be performed I hereby declare that what I claim is,
The construction or arrangement of ports forming a valve for the control or
regulation of the steam supplied to steam engine cylinders said valve consisting of
an inner cylindrical body or part divided into separate chambers or compartments
by dividing walls provided with suitably shaped apertures or ports for passage of
steam, and of an outer cylindrical case or cover also provided with suitable passages
or ports adapted to operate with those of the inner cylinder or valve proper
substantially as described and shown by the Drawings.
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