Year: 1888

page_text: Date of Application, 16th Apr., 1888
Complete Specification Left, 14th Jan., 1889
Complete Specification Accepted, 2nd Mar:, 1889
1, JAMES MAXWELL of 4 Upper Coltbridge Terrace, Edinburgh, in the County of
Midlothian, North Britain, Saw Miller do hereby declare the nature of this invention
to be as follows:-
This Invention relates to improvements in steam engines and has reference to the
rendering more perfect those parts of such engines which have for their object to
relieve back pressure from the pistons, and the release of water which either condenses.
from the steam in the cylinders, or condenses in the steam pipes or comes over from
the boiler by priming..
The Invention consists in providing one or more specially constructed pairs of
relief valves in a passage or passages communicating with each end of the cylinder,
which passage or passages is or may be either cast on the cylinder itself or may be
added thereto externally so that the steam on being admitted into each end of the
cylinder alternately operates the valve or valves in the said passage or passages and
allows the escape of steam or water from the cylinder.
This improvement is of great importance in cases where the engine is situated at a
considerable distance from the sources of steam supply and when a long steam pipe,
When more than one
and a consequent excessive condensation of steam takes place.
valve is employed at each end of the cylinder, the improvements are especially.
important, in respect that they provide for a passage being always open in the event
of one pair of valves becoming stuck as may sometimes be the case from the various
causes which operate to jam or otherwise stop the free action of valves in steam
engines.
In the case of engines with vertical cylinders or inclined cylinders the valves and
their passages may be situated horizontally or at an angle as the circumstances of
each case may specially require.
The special feature in the construction of the said valves consists in forming them
with a projection or flange extending beyond the seat, that is to say, that the projec-
tion or flange is of larger diameter than the valve or scat..
'

page_text: A further feature of improvement consists in dispensing with the ordinary
D-slide valve and in using the valves herein before described as exhaust valves in
which case the said valves are made of larger diameter than when used for relief
valves as herein before described. In this case two admission valves are used for
admitting steam to the cylinder of a steam engine.
1 1300
ST. JOHN V. DAY,
115, St. Vincent Street, Glasgow,
Petitioner's Agent.
Improvements in Steam Engines.
I, JAMES MAXWELL of 4 Upper Coltbridge Terrace, Edinburgh; in the County of
Midlothian, North Britain, Saw Miller 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 :-
My Invention, which relates to improvements in stea n engines, has reference to the
rendering more perfect those parts of such engines which have for their object to
relieve back pressure from the pistons and the release of water which either
condenses from the steam in the cylinders or condenses in the steam pipes or
comes over from the boiler by priming.
The Invention consists in providing one or more specially constructed pairs of relief
valves in a passage or passages communicating with each end of the cylinder, which
passage or passages is or may be either cast. on the cylinder itself or may be added
thereto externally so that the steam, on being admitted into each end of the cylinder,
alternately operates the valve or valves in the said passage or passages and allows
the escape of steam or water from the cylinder.
This improvement is of great importance in cases where the engine is situated at a
considerable distance from the sources of steam supply and when a long steam pipe
and a consequent excessive condensation of steam takes place. When more than one
valve is employed at each end of the cylinder the improvements are especially
important in respect that they provide for being always open in the event of one pair
of valves becoming stuck as may sometimes be the case from the various causes
which operate to jamb or otherwise stop the free action of valves in steam engines.
In the case of engines with vertical cylinders or inclined cylinders the valves and
their passages may be situated horizontally or at an angle as the circumstances of
each case may specially require.

page_text: In order that my Invention may be properly understood and readily carried into
effect, I have hereunto appended one explanatory sheet of drawings on the several
Figures of which corresponding parts are marked with the same letters of reference.
Figure 1, is a longitudinal section of what I believe to be the best arrangement
of valves and their connections for carrying out my said improvements in steam
engines.
Figure 2, is a transverse section corresponding to Figure 1, and Figure 3, is a plan
of the same.
In the said drawings A, A, and B, B, are respectively flanges whereby the casing C,
containing the valves is connected to the opposite ends of a steam engine cylinder
either horizontal, vertical or inclined. The valves D, and E, respectively are formed
with inwardly projecting stems F, F, G, G, which stems abut against each other at
the centre, as shewn by the line a, a. The stems of the valves are formed with
three or other number of radially projecting feathers or ribs b. b, which fit easily so
as to allow the valves D, and E, to move freely backwards and forwards in the
cylindrical holes H, formed in the valve casing C, whilst additional bearing for the
valves D, and 'E, is effected by the wings W, working in the cylindrical holes W¹, in the
centre of the flanges A, and B. In the upper part of the valve casing C, there is a
through port I, and in which there is fitted the tapered plug J. When the plug J, is
turned in the direction shewn in Figures 1 and 2, the passage I, is stopped, that is to
say, there is no communication through it, but when the plug J, is turned in a
direction at right angles to that shewn at Figures 1, and 2, then the port K, in the
plug J, permits of free communication through the port L. The plug J, is kept in its
place in the casing (, by means of the screw gland L. The passage M, in the
casing C, is that through which any steam which would create "back pressure" in
the cylinder or any water which may have collected in the cylinder escapes, and the
passage M, is connected either to the exhaust pipe or to other discharge or in the
case of a high pressure engine, whilst in the case of a low pressure engine the
passage is connected to the condenser at a point above the admission for the injection
of water.
The action of the apparatus is as follows. When the piston in the cylinder of a
steam engine has arrived at the termination of its stroke, and steam is admitted for
the commencement of the return stroke of the piston, at the same instant that the
admission of steam thus takes place, it not only commences to press upon the piston.
but simultaneously therewith fills the passages leading to the valve casing C. At the
instant of reaching the valve casing and assuming it to come from that end of the
cylinder corresponding with the direction of the arrow a, in Figure 1, the steam
pushes the valve E, against its seat E', and by virtue of the two stems G, and F,
abutting against each other on the line a, a, it pushes the valve D, from off its
seat D. This opening of the valve D, gives instant and free discharge for any steam
causing back pressure or any water which may be in the cylinder on the opposite
side of the piston and such steam or water is at once discharged through the branch M,
either into the atmosphere or into a condenser, so that all loss of efficiency of the steam
acting on the piston is by means of my Invention got rid of by virtue of the instan-
taneous opening effected by either of the valves B, or E, according to the direction
of the stroke in which the piston is moving; it being here explained that when
the piston has arrived at the end of its stroke corresponding to the direction of
the arrow x, that the live steam admitted for the next stroke of the piston acts
simultaneously with the instant of its admission upon the valve D, thereby closing it
and opening the valve E.
As it is sometimes advantageous and more especially so when starting a steam engine
into operation to be enabled to permit the steam to blow freely through all parts
connected with the cylinders of such engines the plug J, is more especially provided
for this purpose, whereby, when turned in the direction so as to make a through
opening of the part I, it enables a clear blow through to be obtained from each end
of the cylinder to the other irrespective of the valves D, and E, thus enabling the
water which may have condensed in the cylinders to escape down through the hollow

page_text: in the plug J, into the branch M. So soon as such blow through has been effected
sufficiently to clear the cylinders of water then the plug J, is turned into the position
which closes the port I.
It is to be understood that although the fitting of the casing C, with the blow
through port I, and plug J, is in many cases of much importance and more especially
where the cylinders of the engines are situated at a distance from the boilers so that
along length of steam pipe is required and the condensation of steam is thereby
proportionately increased, yet such port I, and plug J, may in many cases be
dispensed with and in place of such port I, and plug J, a mechanical equivalent
thereof may be substituted.
A further feature of improvement consists in dispensing with the ordinary D-slide
valve and in using the valves herein before described as exhaust valves in which case
the said valves are made of larger diameter than when used as relief valves only.
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. The general arrangement or construction constituting the combination of valves
and valve casings communicating with each. end of the cylinders of steam engines
whereby the opening of free communication with the atmosphere or condenser from
the side of the piston opposite that at which steam is being admitted, is effected
instantaneously with and by the admission of such steam, substantially as herein-
before described and shewn upon the annexed drawings.
2. The construction of the valves D, and E, in two parts so that their stems
respectively lic in cylindrical holes in the valve casing and abut against each other at
the line a, a, substantially as hereinbefore described and shewn upon the annexed
drawings.
3. The construction of the valves D, and E, with the valve part constituting a
projection or flange of larger diameter than the valve seats D₁, and E, substantially
as hereinbefore described and shewn upon the annexed drawings.
4. The combination in or with the valvular apparatus constituting the " "improve-
ments in steam engines" of the through port I, and plug J, with its port K, or the
mechanical equivalent of such an arrangement, substantially as herein before described
and shewn upon the annexed drawings.
5. The dispensing with the ordinary D or equivalent slide valve, and adapting the
valves D, and E, as exhaust valves, substantially as hereinbefore described.
Dated this 12th day of January 1889
ST. JOHN V. DAY,
115, St. Vincent Street, Glasgow,
Applicant's Agent.