Valves and Valve Gear of Steam Engines.
Year: 1888

page_text: Date of Application, 20th Sept., 1888
Complete Specification Left, 20th June, 1889-Accepted, 20:h July, 1889
PROVISIONAL SPECIFICATION.
Valves and Valve Gear of Steam Engines.
I, TOM WILLIAM BAKER of 2 Drysdale Street Kingsland Road London Engineer
do hereby declare the nature of this invention to bo as follows:-
My invention consists of the application of a partially rotative equilibrium valve
or valves for controlling steam or other fluid Engines and to be automatically
controlled by the Governors.
I construct the cylinder of a Steam Engine with a cylindrical valve seating—either
parrallel or taper similar to what is known as a Corliss Valve-and situated at each
end of the cylinder, transversely to the bore or one seating only in the centre; into
these seatings the ports open from the cylinder, and to them I fit a circular annular
valve, having slots or ports and exhaust chambers to correspond, and in partially
rotating to have precisely the same control of the passage of the steam to and from
the cylinder as in the ordinary slide valve, to set up the reciprocating motion of the
piston.
To the centre of this annular cylindrical valve I affix-slightly taper by preference-
another annular valve having suitable slots or ports which shall be called the expansion
valve also partially rotating within the main valve, the spindle of the main valve
being hollow and the spindle of the expansion valve passing through it; to suitable
bell crank levers on these spindles I affix pawls and tappets which being partially
rotated by the eccentric on the main or other shaft come in contact with each other
and with them the expansion valve, so admitting the steam at the same time the main
valve opens.
To these spindles also or to suitable journals I attach controlling sleeves or
eccentrics which are connected to the aforesaid pawls and levers in such a manner
that when the governors pull the sleeves round the spindle the pawls are drawn from
the tappets so disengaging them and suitable springs being affixed to the levers of
the expansion valve on its release, it is pulled to its normal position so cutting off tho
steam instantaneously.
It will be seen that these valves being both annular the steam pressure being
admitted inside them they are always in equilibrium.
In some cases to obtain less clearance I prefer two sets of valves and placed one at
each end of the cylinder but having one admission port only and the exhaust chamber
the tappets and pawls in this case by preference may be controlled by the governors
through suitable rods and sliding studs affixed to the cylinder to shorten or lengthen
their period of contact so controlling the cut off, this arrangement may be also used
to the single centre valve.
These valves and automatic trip gear may be applied to existing Engines and
may be affixed to the end covers of the cylinder if preferred, and the main valve may
be used without the expansion valve at any time.
COMPLETE SPECIFICATION.
Valves and Valve Gear of Steam Engines.
I, TOM WILLIAM BAKER of 2 Drysdale Street Kingsland Road London in the
County of Middlesex Engineer 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 consists of the application of a partially rotative equilibrium valve.

page_text: or valves for controlling steam or other fluid Engines and to be automatically
controlled by the governors.
1 construct the cylinder of a steam Engine with a circular valve seating either
parallel or taper similar to what is known as a Corliss Valve-and situated at each
end of the cylinder transversely to the bore or one seating only in the centre; into
these seatings the ports open from the cylinder and to them 1 fit a circular valve
having passages and exhaust chambers to correspond and in partially rotating to have
precisely the same control of the passage of the steam to and from the cylinder as
in the ordinary slide valve to set up the reciprocating motion of the piston. To the
centre of this annular valve I affix (slightly taper by preference) another annular
valve having suitable slots or ports which shall be called the expansion valve also
partially rotating within the main valve, the spindle of the main valve being hollow
and the spindle of the expansion valve passing through it, to suitable bell crank
levers on these spindles, I affix pawls and tappets which being partially rotated by
the eccentre on the main or other shaft come in contact with each other and with
them the expansion valve so admitting the steam at the same time the main valve
opens. To these spindles also or to suitable journals, 1 attach controlling sleeves or
eccentrics which are connected to the aforesaid pawls and levers in such a manner
that when the governers pull the sleeves round the spindle the pawls are drawn from
the tappets so disengaging them and suitable springs being affixed to the levers of
the expansion valve on its release it is pulled to its normal position so cutting off the
steam instantaneously.
It will be seen that these valves being both annular the steam pressure being
admitted inside them they are always in equilibrium.
In some cases to obtain less clearance I prefer two sets of valves and placed one at
each end of cylinder but having one admission port only and the exhaust chamber,
the tappets and pawls in this case by preference may be controlled by governers
through suitable rods and sliding studs affixed to the cylinder to shorten or lengthen
their period of contact, so controlling the point of cut off, this arrangement may also
be used to the single centre valve.
These valves and automatic trip gear may be applied to existing Engines and may
he affixed to the end covers of the cylinders, if prefered and the main valve may be
used without the expansion valve at any time.
To more fully describe this invention I append descriptive drawings. Fig. I is the
section of an Engine cylinder with ports A and B communicating to a circular valve
chamber in which is the main valve C which partially rotates on trunnions K K
having suitable passages through it communicating to the ports also with the
cylindrical expansion valve D fitted inside; it will be seen that the steam being
admitted to one end of the valve chamber H Fig. II and passing through suitable
openings at the end of the main and expansion valves, on the rotating motion of
those valves bringing the ports or passages in a line with each other the steam is
admitted to the cylinder at one end and then by a similar movement to the other
end so acting alternately on the piston it will be also seen both the main valve C and
expansion valve D are cylindrical consequently contain the working pressure so that
no friction is set up and a perfect equilibrium obtained. The exhaust chamber I on
the main valve being partially rotated opens a communication between the ports and
the exhaust outlet J, both the admission and exhaust being controlled similar to the
ordinary slide valve the surface being Circular instead of flat. The dotted lines in
Fig. I shew the application of the valves to either end of the cylinder with single
steam passages in each. Fig. III is an elevation of the Trip Gear. Fig. IIII is an
end view of same. A A are the main valve levers which receive their reciprocating
motion from an eccentric on the main or other shaft causing the main valves to
partially rotate B B are the levers actuating the expansion valves having tuppets on
their ends F, G G are pawls having catches H H at their ends which engage with
the tappets FF so that the main valves being drawn over by the levers the pawls
being attached to them engage with the tappets and both valves are opened together
at either end of the cylinder alternately. The levers CC being controlled through

page_text: the Governor rod G R have affixed to them controlling sleeves working on the
expansion valve spindles E E and on these sleeves are studs II which come in
contact with the pawls G G drawing them outwards as they are pulled towards them
so that to get an early cut off the studs II being depressed by the governors throw
outwards the pawls so disengaging them from the tappets the spring pistons D D
bringing the levers B B instantaneously to their rests so cutting off the steam
admission. This arrangment may be used to a single valve with double Ports as in
Fig. I.
Having now described and ascertained the nature of my said invention and in
what manner the same is to be performed, I declare what I claim is :-
First. The use and employment of partially rotating cylindrical valves having
steain passages through their sides and exhaust chambers on their outsides working in
circular seatings and substantially as described in the accompanying Drawings.
Second. The use and employment of partially rotating cylindrical expansion valves
fitted inside the main valves substantially as described in. the accompanying
Drawings.
Third. The combination of parts forming an automatic trip valve gear substantially
as described in the accompanying Drawings.
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