Improvements in and connected with Steam Engines.
Year: 1891

page_text: Date of Application, 5th May, 1891
Complete Specification Left, 7th Mar., 1892-Accepted, 26th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in and connected with Steam Engines.
1, GABRIEL DAVIS, of S. Helen's Works, Abingdon, in the County of Berks,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to an improved construction and arrangement of piston
valve, for use in steam engines of all kinds ;. its objects being to reduce the steam
space, or clearance between the parts of the engine involved in the working thereof,
and to effect a considerable saving in the consumption of steam.
In engines, as hitherto constructed, the valves are defective in many respects.
It has been the practice to place valves at a distance from the point of entry of
the steam to the cylinder, the steam, in its passage thereto, being apt to become
cooled; while these constructions have been, more or less, expensive and compli-
cated, by reason of the number of ports, and parts, necessary for the effective
working thereof.
In an engine constructed according to my, invention the valve casing or chamber
is connected to the ends of the cylinders; this casing or chamber is formed with an
inlet port, and an exhaust port, which latter, in the case of a compound engine may
lead directly to the low-pressure valve chamber. The upper part of the casing
projects a short distance into the cylinder, the said upper part being provided with
the necessary ports for the admission and exhaustion of the steam to and from the
cylinder; and a sleeve, through which the; piston rod passes, thus the steam .is
brought into immediate contact with the piston.
The valve is constructed in the form of a hollow cylinder, having an annular
space cast in its circumference. This space always covers the live steam inlet, and
affords the necessary communication with the main steamport and the cylinder.
The exhaust steam from the cylinder is controlled by the edge of the valve, which
by its movement admits, and cuts off, the steam, as required; the exhaust steam
passes through the interior of the valve to the exhaust port on the opposite side of
the casing, and, as this steam never passes again. to the inlet ports, the cooling of
those ports and the parts in close proximity. thereto is entirely obviated. The
friction incidental to the travel of the piston rod through the sleeve or bearing may
be diminished by grooving the face of the said sleeve which bears against the
piston rod. A gland with packing is fitted to the cover of the casing, through the
former of which the piston rod works. Ordinary linings may be employed as will
be readily understood.
The valve may be actuated by any suitable valve gear, by levers, or connecting
rods and eccentrics from the crank shaft, or other devices.
By my improved arrangement the cylinder becomes steam jacketed at a minimum
of cost.
1 A 1901
COMPLETE SPECIFICATION.
Improvements in and connected with Steam Engines.
I, GABRIEL DAVIS, of St. Helen's Works, Abingdon, in the County of Berks,
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 :-
This invention relates to an improved .construction and arrangement of piston-

page_text: valve applicable for use in steam-engines of all types, and has for its object to
reduce the steam space or clearance between the parts of the engine involved in
the working of the valve, whereby a considerable saving in the consumption of
steam is effected.
In engines as at present constructed the disposition of the valves renders them
unfavourable to the above object and defective in various ways-the valves being
placed at a distance from the point of entry of the steam to the cylinder, the
steam in its passage thereto becomes cooled. These constructions are also of a
more or less expensive and complicated nature, by reason of the number of ports
and parts necessary to their effective working.
In the accompanying drawings, Fig. 1 is a section shewing the mode of applying
my improved valve to the end of a steam cylinder; Fig. 2 being a plan view in
section of the valve.
A is the valve casing or chamber connected to the end of the cylinder B. C is
the piston-rod and D the piston. The valve casing projects a short distance into
the cylinder as shewn at a, and is provided with a steam admission port a', and an
exhaust port a². The latter may, in the case of a compound engine, lead directly
to the low-pressure valve chamber. From the part a of the casing is extended a
sleeve a³ through which the piston-rod C works.
The valve is constructed in the form of a hollow cylinder b, having an annular
space ', cast or otherwise formed in its circumference. This space b' is in constant
communication with the steam admission port a', and through the port a' com-
municates with the cylinder B.
In the drawing the valve is shewn in the act of admitting steam to the cylinder.
By the time the live steam has performed its work, the valve, which moves
longitudinally, will have closed the admission port a; the live steam then having
access only to the space b'. The exhaust steam is thereby compelled to pass
through the port a' and over the edge of the valve, through the interior thereof,
to the exhaust port a².
It will be seen that the exhaust steam passes directly to the exhaust port and is
conveyed away, or, as previously stated, it may be utilised in the low-pressure valve
chamber. The live steam port a' being in direct communication with the cylinder,
the cooling of the admission ports and the parts in close proximity thereto by the
exhaust is thereby obviated.
The friction incidental to the working of the piston-rod C through the sleeve a³
may be diminished by any known means, or by forming grooves in the bearing face
of the sleeve. A gland E and packing is fitted to the cover F of the valve casing,
through the former of which the piston-rod works steam-tight. Ordinary linings
may be employed where necessary as will be readily understood.
The valve may be actuated, and its movements controlled, by any suitable gear.
The valves being situate at the end of the cylinder they can be worked in harmony
or separately as occasion may require. Metal packing-rings may be provided for
preventing leakage of steam, and, if desired, the valve may be constructed with
more admission ports than one.
The improved construction and arrangement of valve and valve chamber, as will
be readily seen forms a steam-jacket to the cylinder.
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 a steam-engine, a piston-valve arranged at the top and bottom or at the
ends of the cylinder, the port for admitting the live steam being in direct com-
munication with the cylinder, while the exhaust steam passes away through a separate
exit, whereby loss of steam in working by the steam having to travel through various
passages or ports, or by radiation is diminished, and the effective power of the
engine is materially enhanced, substantially as described.
2. For use in steam-engines, the improved construction and arrangement of

page_text: piston-valve, substantially as described with reference to the accompanying
drawings.
3. In a steam-engine, the combination, with the steam cylinder, of the improved
piston-valve, constructed and arranged substantially in the manner and for the
purposes specified.
Dated thin 1th In of Mauck 1000
GABRIEL DAVIS.