IMPROVEMENTS IN IMISSION AND EMISSION VALVES FOR STEAM AND OTHER MOTIVE ENGINES
Year: 1876

page_text: LETTERS PATENT to Henry Holford, of Newton Iron Works, Hyde, in the
County of Chester, Engineer, and John Slee, of the same place, Manager, for
the Invention of "IMPROVEMENTS IN IMISSION AND EMISSION VALVES FOR
STEAM AND OTHER MOTIVE ENGINES."
Scaled the 18th May 1877, and dated the 1st December 1876.
PROVISIONAL SPECIFICATION left by the said Henry Holford and John
Slee at the Office of the Commissioners of Patents on the 1st December 1876.
HENRY HOLFORD, of Newton Iron Works, Hyde, in the County of Chester,
Engineer, and John Slee, of the same place, Manager. "IMPROVEMENTS IN IMMISSION
AND EMISSION VALVES FOR STEAM AND OTHER MOTIVE ENGINES."
Our Invention is intended more particularly for direct acting engines, such as
steam and other motive pumps without cranks and fly wheel shafts, where the valves
are to he worked from the direct reciprocation of the piston rod, though our im-
proved valves are applicable when brought into action by connection with excentrics
or tappets in the case of rotary engines.
Our Invention consists in an improved combination and arrangement of two
cylindrical reciprocating valves. The main valve fits as a piston, as nearly steam-
tight as possible, into a cylindrical steam chest, which has steam and exhaust ports
and passages leading to each end of the steam cylinder in the ordinary manner.
The main valve receives its steam from what may be termed the top side of the
valve chest, from which the steam passes through passages to ports in the valve
which supply steam to the ports in the cylinder. The parts of the main valve,
which regulate the immission and emission of the motive power to and from the
cylinder, are similar to those of the ordinary slide valve.
Working in a cylinder in the centre of the main cylindrical slide valve, and fitting
like a piston, there is a small cylindrical slide valve which is hollow, and is closed.
at its two ends, but it is provided with ports and passages. There is a passage in
the main valve at each end which communicates between the end of the main valve
and a port in the interior cylindrical face of the main valve, and there are corre-
sponding ports and passages in the central valve which may be termed steam
and exhaust ports and passages, the steam passages passing across the central
valve.

page_text: When the main valve is at one end of its stroke, say at the commencement of a
stroke of the piston of the engine, the steam is exhausting from that end of the
steam cylinder and is entering at the other end of the cylinder, and as the central
valve is actuated by a lever in connection with the piston rod of the engine, so as to
move in the same direction as the piston, it will be at the commencement of that
stroke of the piston above referred to, at the opposite end of its stroke in relation
to the main valve, in which position the passages in the central valve will allow the
space at end, to which the main valve has moved, to be in communication with
the exhaust hollow of the central valve, which hollow is in communication by ports
in the central and main valve with the exhaust cavity of the main valve, and one
of the steam passages in the central valve will be in communication with a port in
the main valve, communicating with the steam passage, and also with the port and
passage in the main valve leading to that end of the main valve from which it
has moved; but when the piston has arrived at the end of its stroke, the central valve
has also arrived at the same end of its shorter stroke; and the ports and passages
which were open or uncovered are now closed, and those which were closed or covered
are now open, consequently the steam is admitted and exhausted from the opposite
end of the main valve to that first referred to, and thus it is reversed in position.
The central valve has only a small part of the motion of the piston rod, and the
residue of steam left in the valve chest at each end of the main valve forms a
cushion, so that it reverses at each end of the stroke without shock. The central
valve is connected with the lever actuating it by a rod passing a stuffing box in
one of the end covers of the valve chest.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Holford and John Slee in the Great Seal Patent Office on
the 24th May 1877.
HENRY HOLFORD, of Newton Iron Works, Hyde, in the County of Chester,
Engineer, and John Slee, of the same place, Manager. "IMPROVEMENTS IN IMMISSION
AND EMISSION VALVES FOR STEAM AND OTHER MOTIVE ENGINES.”
Our Invention is intended more particularly for direct acting engines, such as
steam and other motive pumps without cranks and fly wheel shafts, where the valves
are to be worked from the direct reciprocation of the piston rod, though our im-
proved valves are applicable when brought into action by connection with excentrics
or tappets in the case of rotary engines.
Our Invention consists in an improved combination and arrangement of two
cylindrical reciprocating valves. The main valve fits as a piston, as nearly steam-
tight as possible, into a cylindrical steam chest, which has steam and exhaust ports
and passages leading to each end of the steam cylinder in the ordinary manner.
The main valve receives its steam from what may be termed the top side of the
valve chest, from which the steam passes through passage to ports in the valve
which supply steam to the ports in the cylinder. The parts of the main valve,
which regulate the immission and emission of the motive power to and from the
cylinder, are similar to those of the ordinary slide valve.
Working in a cylindrical hole in the axis of the main cylindrical slide valve, and
fitting like a piston, there is a small cylindrical slide valve which is hollow, and is
closed at its two ends, but it is provided with ports and passages. There is a
passage in the main valve at each end which communicates between the end of the
main valve and a port in the interior cylindrical face of the main valve, and there
are corresponding ports and passages in the central valve, which may be termed
steam and exhaust ports and passages; the steam passages passing along the
exterior of the central valve.
When the main valve is at one end of its stroke, say at the commencement of

page_text: a stroke of the piston of the engine, the steam is exhausting from that end of the
steam cylinder and is entering at the other end of the cylinder, and as the central
valve is actuated by a lever in connection with the piston rod of the engine, so as
to move in the sanie direction as the piston, it will be at the commencement of that
stroke of the piston, above referred to, at the opposite end of its stroke in relation
to the main valve, in which position the passages in the central valve will allow the
space at the end to which the main valve has moved to be in communication with
the exhaust hollow of the central valve, which hollow is in communication by ports
in the central and main valve with the exhaust cavity of the main valve, and one
of the steam passages in the central valve will be in communication with a port in
the main valve, communicating with its steam passage, and also with the port and
passage in the main valve leading to that end of the main valve from which it has
moved; but when the piston has arrived at the end of its stroke, the central valve
has also arrived at the same end of its shorter stroke, and the ports and passages
which were open or uncovered are now closed, and those which were closed or
covered are now opened, consequently the steam is admitted and exhausted from
the opposite end of the main valve to that first referred to, and thus it is reversed
in position.
The central valve has only a small part of the motion of the piston rod, and the
residue of steam left in the valve chest at each end of the main valve forms a
cushion, so that it reverses at each end of the stroke without shock. The central
valve is connected with the lever actuating it by a rod passing through a stuffing
box in one of the end covers of the valve chest.
Fig. 1 is a longitudinal section of part of a cylinder, and the valve chest, and
valves; and Fig. 2 is a cross section of the same taken in the line A, B; Fig. 1 and
Fig. 3 is a side elevation of an engine and pump combined, having our Invention
applied, and showing the manner in which the valves are actuated.
A is the steam or other motive cylinder; a¹, the passages in it leading from each
end of the cylinder in the ordinary manner to the cylindrical valve chest, A2, hav-
ing its two ends closed by covers a³; a is the exhaust port of the main cylinder;
and a, the exhaust outlet; is the inlet for steam or motive power to the valvo
chest; is the main cylindrical valve fitting the cylindrical steam' chest like a
piston. In its upper side it has a passage which keeps opposite or in com-
inunication with the inlet a for the motive power in every position of the main
valve (b), and this passage b¹ passes on each side of the central part of the valve (sec
Fig. 2) to the ports be in the valve for supplying steam or other motive power to
the ports a¹ of the main cylinder. The under side of the main valve has an exhaust
cavity b³ which communicates in the ordinary manner between the exhaust port a
and the ports a' of the main cylinder. The exhaust cavity 63 has an opening b
which communicates with the central valve.
The main valve is prevented from rotating or getting out of position by a screw b³,
the point of which enters a longitudinal groove in the side of the main valve. At
each end of the main valve there is a passage 60 which communicates with the in-
terior cylindrical face of the main valve for the central valve and the space in the main
valve chest at its end of the main valve. There is also a small hole 67 which com-
municates between the steam or other motive passage band a channel e¹ on the
exterior of the central valve c which is hollow, but closed at the two ends, having
ports in it to come opposite when working to the ports be in the main valve.
There is also a port c³ in the central valve c which is always in communication with
the exhaust cavity b³.
The central valve is connected with one end of a rod which passes through a
gland in the cover for the end of the valve chest; the outer end of this spindle or
rod being jointed with a rod that connects it with a lever d having its fulcrum d
on a bracket sccured to the framing, the end of this lever being arranged to slide
in a socket jointed on the pin de on a collar secured on the piston rod e.
In Fig. 1 the main valve b is shown at one end of its stroke, namely, to the
right (looking at the Drawing) and the piston of the main cylinder is supposed to

page_text: be moving towards the same end of the cylinder, as the steam or motive power is
supposed to be exhausting from that end of the cylinder and entering at the
opposite end. The central valve c is also supposed to be moving in the same
direction as the main piston (to the right), and is supposed to have nearly arrived
at the end of its stroke, its remaining movement allowing the motive power to enter
the right-hand passage b from that channel c', and the motive power to escape
from the left-hand passage through the exhaust port c; this causes the main
valve b to move from the right to the left (looking at the Drawing, Fig. 1). This
movement of the main valve closes the exhaust port on the left, but the motive
power port on the right keeps in communication with the right hand end of the
valve chest.
As the central valve travels with the main piston, its left exhaust port again
comes in communication with the left passage, and passes over it until the channel c¹
communicates with the left-hand passage b, and the right-hand exhaust port c with
the right hand passage 66, and the main valve is reversed, moving from left to right,
and so on in the order described.
We have now particularly described the nature of our Ivention, and the mode of
carrying the same into effect, and claim as our Invention the combination and ar-
rangement of two valves for working steam or other motive engines, and also the
mode of actuating the same, substantially as herein-before described and illustrated
by the Drawings.
In witness whereof, we, the said Henry Holford and John Slee, have here-
unto set our hands and seals, this Sixteenth day of May A.D. 1877.