Improvements in Steam and other Expansion Engines.
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
Improvements in Steam and other Expansion Engines.
I, ARTHUR EASTWOOD of 26 Brownlow Street in the City of Liverpool,
Contractor, do hereby declare the nature of this invention to be as follows:-
This invention has for its object an arrangement of steam engine whereby there
shall be much less back pressure than there is at present, and yet the steam ports
can remain of only sufficient size to supply the steam.
The invention consists in having two sets of ports, say one at each side of the
cylinder, or they may be at right angles to each other. One set are the ordinary
steam and exhaust ports, but made only of the size requisite for the steam. The
other set of ports are for exhaust only and are subsidiary ports, they can if
desired he in the form of a D valve, exactly similar to the ordinary steam ports,
but with sufficient lap so that the valves shall never leave the ports bare beyond its
end, though of course if the chamber containing the valve were hermetically
sealed it would not be a very greatly injury to have shorter valves and leave the
ports at each end of the stroke.
Another plan is to have short exits from the cylinder at each end and an
exhaust close to it, and have two valves arranged on the same, or different spindles,
in this case all loss through steam in the exhaust port is avoided. In its very
simplest form namely that for high pressure non-condensing engines the exhaust
ports can be omitted, and a simple pair of valves placed on a couple of ports
opening from the cylinder. These valves then at once exhaust the steam into
the air.
Dated the 5th day of November 1901
I, ARTHUR EASTWOOD of 26 Brownlow Street, in the City of Liverpool,
Contractor, 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 :-
This invention has for its object an arrangement of steam engine whereby there
shall be much less back pressure than there is at present, and yet the steam ports
can reinain of only sufficient size to supply the steam.
The invention consists in having two sets of ports, say one at each side of the
cylinder, or they may be at right angles to each other. One set are the ordinary
steam and exhaust ports, but made only of the size requisite for the steam. The.
other set of ports are for exhaust only and are subsidiary ports, they can if desired
be in the form of a D valve, exactly similar to the ordinary steam ports, but with
sufficient lap so that the valves shall never leave the ports bare beyond its end,
[Price 8d]

page_text: though of course if the chamber containing the valve were hermetically sealed it
would not be a very great injury to have shorter valves and leave the ports at each
end of the stroke.
Another plan is to have short exits from the cylinder at each end and an
exhaust close to it, and have two valves arranged on the same, or different
spindles, in this case all loss through steam in the exhaust port is avoided. In
its very simplest form, namely that for thigh pressure non-condensing engines, the
exhaust ports,can be omitted, and a simple pair of valves placed on a couple of
ports opening from the cylinder. These valves then at once exhaust the steam
into the air.
The accompanying drawings set forth an apparatus in which revolving instead
of D valves are used, and illustrate my latest type.
In these,
Figure 1 is an elevation of a cylinder with this form of valve gear attached.
Figure 2 is.a plan of the same.
Figure 3 is an enlarged fragmentary section through the cylinder valves and
ports.
Figure 4 is a sectional elevation through the cylinder and valves.
Figures 5 and 6 are elevation and plan of the valve showing the means by which
the cut.off and admission may be regulated.
Figure 7 is a sectional projection of Figure 5.
Figure 8 is an enlarged fragmentary section of the valve.
Referring to Figures 1, 2, 4-
A is part of the bed plate to which the cylinder B is attached; C the piston
rod, D the steam pipe. E is the stuffing box of the valves, F the valve spindles.
RR' are steam and exhaust valves respectively. Secured to the head of the valve
spindles F are cranks G having crank pins H to which the connecting rods L are
attached. To the crank pins Hare attached smaller cranks I, also having pins J.
The pins J are linked together by the connecting rod N.
In Figure 3, R R¹ are the steam and exhaust valves respectively. P and P¹ the
steam and exhaust ports. O is the piston. S is the cylinder casing.
Figures 5, 6, 7, 8 are views of the valve showing the means for regulating the
cut-off and admission of steam. U are the strips of metal fixed to the valve by
bolts V. T are the parts of the valve to which the strips U are boited.
I will now describe the action of this form of valve.-Steam enters through the
pipe D into the valve R, which is operated by an eccentric on the main shaft by
means of the connecting rod L and crank G. This valve continues to rotate and
admits steam alternately to each end of the cylinder. The exhaust valve R' is
operated in a similar manner, opening to exhaust each end of the cylinder at the
correct period of the stroke. Now it is clear that there are two dead points during
each revolution of the cranks G and valves R and R', but it will also be seen in
Figure 2 that these cranks G are placed upon the valves R and R' in such a
position that when one crank is on the dead centre the other crank will be in
the best position for doing work. Now on the crank pins H, as before described,
there are placed other cranks I having crank pins J. These pins J are connected
by a rod N, so when one of the cranks G is on the dead centre, the other is
in the best position for doing work and being connected as above described, the
one crank will assist the other during the period that it is in the vicinity of the
dead centres.
The steam entering the cylinder may be regulated by placing strips of metal on
the admission or cut-off edges of the valve as shown by Figures 5, 6, 7, 8. The
exhaust may be regulated in a similar manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improvement in steam and other expansion engines which consists in

page_text: having two valves, a steam or combined steam and exhaust valve of sufficient size
to admit the requisite amount of steam and an exhaust valve for freely allowing
the exhaust steam to escape, substantially as described.
2. The arrangement of the valves substantially as described and illustrated.
Dated this 17th day of June 1895.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.