IMPROVEMENTS IN VALVE GEAR FOR STEAM ENGINES
Year: 1885

page_text: I SAMUEL GRAHAM BROWNE of 11 Queen Victoria Street, London, E.C. Engineer,
do hereby declare the nature of my invention for "IMPROVEMENTS IN VALVE GEAR
FOR STEAM ENGINES" to be as follows:-
My invention relates to an improved valve gear and the distribution of the
steam and exhaust ports, such gear being specially adapted to direct acting
pumping Engines.
The main valve chest is divided into two chambers of convenient form, each
chamber being provided with a steam and exhaust port, the steam ports entering
the cylinder preferably some distance from its ends; the exhaust ports may be
connected with each other. These ports are controlled by suitable valves, connected
with each other, say a
valve, or they may be moved independently;
these valves providing for the admission of steam or exhaust to the respective sides
of the main piston by their movement or reciprocation as required. Secondary
steam passages, leading to the ends of the cylinder and uncovered by the valves
when respectively on their exhaust traverse, may be used, admitting steam behind
the piston. I provide an expansion valve chest through which steam is admitted
to the main valve chest, such chest having suitable ports or openings communicating
respectively with each chamber of the main chest; these ports being provided with
suitable valves so arranged that by their traverse or movement the communication
to the one chamber will be closed the other opened, the alternate movement of such
valves cutting off steam from the then driving valve chest, but admitting steam to
the other, awaiting the reversal of the main valve to reverse the main piston. The
expansion valves may be of the most suitable character to suit the general
construction of the engine, say of the flat, balance piston, or lifting type.
The main and expansion valves may be moved either directly from the engine
gear, or by steam moved pistons.
Provision however being made to admit steam directly to the main valve
chambers converting the gear into that of a non expansive type.

page_text: I SAMUEL GRAHAM BROWNE of N° 11 Queen Victoria Street London E.C.
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
VALVE GEAR FOR STEAM ENGINES and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to an improved valve gear and the distribution of ports
in Direct acting Steam Engines, and to describe my invention I refer to the
accompanying drawings. Figs. 1, 2, & 3 shew modifications of valve gear and
Fig. 4 shews a plan of a partially ballanced expansion valve. Referring to
Fig. 1-A A represent main valve chests, one end.being shewn in section,
B B main valves, C_C_expansion valve chest, D D communicating ports from
same, to main chest E E piston-expansion-valve, adjustable for different grades of
expansion by means of a right & left hand screw FF. The pipe H H, controlled
by cock G, admits steam to both chambers of main valve chest when desired;
converting the engine into a non-expansive engine at will. Fig. 2 shews a similar
arrangement, cylindrical valves being used instead of D valves and piston valves,
the grade of expansion being altered by varying the traverse of the expansion
valve rod J, the main valve being actuated by the valve rod K. In Fig. 3. the
main valves B B are shown reciprocated by the steam moved piston L working in
the cylinder M which is controlled by the valve N moved by valve rod W. The
main valve chest A A is cast or bolted to main cylinder and separated into two
chambers by diaphragm O, the ring P. P on valve rod K. K. sealing the chambers
and preventing the passage of steam either between the chambers or to the
cylinder M. I use the rod K of such diameter and strength that the valves B B
can be passed through side doors and slipped on the decreased sections of rod K. K
as shewn, thus enabling the rod K K to be inserted and withdrawn. Similar letters
in figures 1. 2 and 3 represent similar parts, any of which may be combined in one
arrangement to effect a similar purpose. Fig. 4 shews a plan of the expansion
valve a section of which is given in Fig. 3; the expansion valve E is fitted with
a loose bar R through which the holes S. S are drilled in such a position that when
either end of the expansion valve E comes in contact with the end of the bridle U,
one of the holes S will be brought over its corresponding hole T in the valve E,
thus admitting steam from chest C into the chamber A which has been cut off from
chamber C by the previous traverse of the expansion valve, and relieving the
valve E from the pressure due to the area of the port D, before the bridle
commences to move the expansion valve itself; lost motion being provided in the
bridle as shewn, to enable it to effect this purpose. In direct acting engines by
the arrangements shewn, steam will always be admitted to one chamber of the main
valve chest; thus when the expansion valve cuts off steam from the driving chest,
the opposite chest will be open to steam for reversing the movement of the
main piston on the reversal of the main valve, suitable provision being made for
admitting steam to both cheats when desirable in starting.

page_text: 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. In direct Acting Engines the use of an expansion valve gear constructed,
combined, and arranged to operate substantially as described and illustrated
Figs. 1. 2 and 3 of the drawings, and for the purpose specified.
2. The valve Chests A A with valves B, in combination with the Expansion
valve chest and valve E. and Connecting steam passage H H, substantially as
described for the purpose set forth.
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