Improvements in the Valve Gear of Semi-rotary Engines and Pumps.
Year: 1895

page_text: Date of Application, 20th Feb., 1895-Accepted, 27th Apr., 1895
Improvements in the Valve Gear of Semi-rotary Engines
and Pumps.
I, SYDNEY AUGUSTUS HUGH NOEL, of Castle Farm, Caerphilly, in the County
of Glamorgan, Master Brewer, do hereby declare the nature of this invention to be
as follows:
My invention relates to improvements in the valve gear of semi-rotary engines
and pumps and the object of it is to provide improved means for imparting the
necessary reciprocating motion to a double piston valve or to the oscillating rotary
valve of an engine, pump, or other similar mechanism.
In carrying it into effect, I provide a chamber outside each end of a double
piston valve, into which live steam can flow. As the working piston reaches the
end of its stroke, a wiper which is carried by the axle of the said piston, engages a
valve whose face forms part of the internal face of the chamber on that side of the
engine and pushes it inwards off its seat whereby the chamber is exhausted and
the piston valve, pushed over to that side of the engine by the pressure of the live
steam. The reciprocating linear motion of the double piston valve above mentioned
is communicated to a rotary oscillating valve by means of a slot in the stem of
the former into which is entered a finger fast to and projecting radially from the
latter.
Referring to the accompanying figures which are to be taken as part of this
Specification and read therewith,
Figure 1 is a perspective view of a steam engine and pump, the former being
fitted with my improved valve gear.
Figure 2 is a section through the engine only in the plane of the axis of its
working cylinder.
Figure 3 is a plan of the wiper and the valve spindle; and Fig. 4, one of both
wipers and spindles.
A is the working cylinder; B, B, the working pistons of the well known
oscillating or vibrating type and C, their axle. The pistons are shewn as packed
to the sides and ends of the working cylinder by means of strips b kept up to their
respective surfaces by springs b'.
D is the steam supply. E is a steam chest in which there is adapted to work
with a reciprocating linear motion, a double piston valve consisting of two
pistons F, F, held together by a rod fat a sufficient distance apart to prevent either
passing the mouth of the supply D.
It is evident that when steam is fed through the supply D into the steam chest E,
the valve will not be moved in either. direction because the pressures towards
either end of the chest E are equal. According to the present invention, there are
established equal pressures inside the steam chest, but outside the pistons F, F ;
provision being made at the same time for suddenly exhausting that one of the two
outside pressures which happens to be in the direction in which it is required that
the valve shall move next. Such provision consists of a clearance space g com-
municating with a port 9 delivering into a chamber g² from which there is
communication controlled by a spindle valve g³, with a port g leading into the
main exhaust, while the spindle of the valve g³ projects through the block 9 which
carries the valve g³ and provides its seating, into the path of a wiper 9 held by an
adjustable arm 97 to the engine axle C. The provision just described is repeated
at the other end of the engine. The action of it is as follows. The supply of

page_text: steam through the pipe D being constant, there is an equally constant leakage past
the pistons F, F, into the chambers 92, 92, and one which suffices to keep the
valves on their seats. As one of the working pistons B approaches the end of
its stroke, the respective wiper g engages the projecting end 98 of the spindle of
the valve g³ and pushes the latter off its seat. The pressure in the chamber g³,
port gl and clearance space g, at once drops and the valve is moved through its
next stroke accordingly.
The above described combination of oscillating working piston axle, valve gear,
and piston valve having a reciprocating linear motion, is complete in itself for
controlling a set of ports from any steam chest to the working cylinder, when the
valve is a slide valve. When it is a semi-rotary or vibrating one, there is combined
with it, the above described combination, and in the following way.
I is a second steam chest of circular, cross section; and J, the semi-rotary or
vibrating valve, adapted to work therein. ¿, are the ports to the working cylinders
respectively, and 2 is the exhaust port. The steam chest I is open at the top to
the steam chest E and through this opening there projects a finger or stud *.
This latter is fast to the valve J and is radial to it. It enters a slot j³ having the
contour of an inverted V, cut vertically up through the axis of the rod and longi-
tudinally thereof. It will be observed that the portsjj and 2 open out of the
bottom of the steam chest I so that the valve J straddles them and can also be
easily kept down on its seat by the pressure of the steam upon it. The desired
motion is given to the valve J by the engagement of the rod with the finger *,
the linear motion of the former and the arcual motion of the latter being equal to
each other, and the mouths of the ports j, j¹ and being set out accordingly.
"
I have spoken of "steam and "steam engine" in describing the present
invention, but it is to be understood that the nature of the motor fluid does not limit
the scope of the invention and that the latter is applicable to all semi-rotary engines,
pumps, and the like.
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 combination of oscillating working piston axle, valve gear, and piston
valve having a reciprocating linear motion, as set forth.
2. The combination with a linearly reciprocating piston valve, of equal external
pressures outside each end thereof and means for exhausting one of them immediately
previous to the desired travel of the said valve towards the exhausted pressure, as
set forth.
3. The combination of oscillating working piston axle, valve gear, piston valve
having a reciprocating linear motion, semi-rotary or vibrating valve, and connection
between the two valves whereby the linear motion of the one produces an arcual
motion in the other, as set forth.
Dated this 20th day of February 1895.
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.