Improvements in and connected with Corliss and similar Valves.
Year: 1897

page_text: Date of Application, 2nd Oct., 1897
Complete Specification Left. 25th June, 1898-- Accepted. 13th Aug.. 1898
PROVISIONAL SPECIFICATION.
Improvements in and connected with Corliss and similar Valves.
We, NORMAN MACBETH and HENRY WOOD, both of the Victoria Foundry,
Bolton, in the County of Lancaster, Engineers, do hereby declare the nature of
this invention to be as follows:-
Our said invention relates to improvements in, and connected with Corliss, and
other valves, which are actuated by a trip or release gear, as is well understood.
In this type of valve motion, when the valve is released by the trip gear it is
rapidly closed by means of a weight or spring.
The method now generally in use for effecting this when springs are used, is
to connect the valve with a piston working in a cylinder or dash pot. In or con-
nected with the dash pot is a coiled or other form of spring which is partly com-
pressed when the valve is closed and at rest, and is more fully compressed as the
valve is opened. The function of this spring is to effect a rapid closing of the
valve when it is released by the trip motion.
When simple falling weights are used the closing of the valve is too slow to
give the desired sharpness of cut-off.
The method of utilising the compressed spring to effect the closing of the
valve in the old manner is subject to certain disadvantages, for instance, if an
early cut off is required, the spring will not be so much compressed as is the case
with a late cut off, and would therefore not be as strong, although a greater
strength of spring is desirable for the earlier points of cut off than for the later
ones. This is desirable in order to compensate for the inertia of the parts set
in motion in closing the valve, and also as in the case of Corliss valves to overcome
the greater friction caused by working the valve over the lap when the port is
covered.
The object of our invention is to overcome this defect which we do by provid-
ing means whereby the spring may be subjected to a greater amount of com-
pression when required to close the valve at the early points of cut off and to a
less amount of compression at the later points of cut off.
By these means no matter whether the cut off be early or late the spring may
be made always equally effective in causing a rapid and perfect closing of the
valve at the required times.
In carrying our invention into effect we provide a suitable dash pot, secured to
the floor or any suitable part of the engine. Within the dash pot works a piston
to which is secured the rod connecting to the valve.
The dash pot is provided with air relief valves or other means to allow for the
gradual escape of air on the descent of the piston as is well known.
The pendent rod is connected to the piston of the dash pot by links or other suit-
able means, and upon this rod we mount a sliding weight or load. This load
preferably consists of a number of removable discs of metal mounted upon a
hollow cylindrical carrier. A coiled or other form of spring is disposed around
or in connection with the pendent rod below the load and abutting against an
adjustable stop upon the pendent rod. The sliding load compresses the spring,

page_text: the amount of such compression being varied at will by increasing or diminish-
ing the number of weights, and by operating the adjustable stop according to
the weight of the load." When the valve is opened the piston is moved in the
dash pot thereby raising the pendent rod with its sliding load and compressed
spring.
On the release of the valve the compressed spring in expanding effects the
rapid closing of the valve. The sliding weight falls and again compresses the
spring previous to the succeeding opening of the valve.
In performing the work done in compressing the spring the inertia of the
weight or load plays an important part in effecting the desired result, thus when
the valve commences to open the inertia of the load holds it back to some extent
and causes an increased compression of the spring for the early points of cut off.
In a contrary manner the inertia of the load causes it at the later points of
cut off to make a greater length of stroke in rising than the stroke of the adjust-
able stop on the pendent rod, thus relieving the spring of its load and consequent
compression to some extent when the valve is released at a point of late cut off.
This effect is peculiarly marked in cases where the valve is as usual opened by
the motion of a revolving excentric, as the motion of the valve and the pendent
rod becomes slower towards the end of the stroke or throw of the excentric, while
at the same time the motion of the weight or load on the spring is increased by
its inertia, thus relieving partially the compression of the spring.
To prevent the too abrupt descent of the sliding load upon the spring we may
provide the pendent rod with a piston working within the cylindrical carrier of
the load, and with an air cushion between the piston and the descending carrier,
tending to bring the load quictly to rest in a position somewhat above or clear
of the internal piston on the pendent rod, the amount of such clearance being
regulated by the adjustable stop.
.
Small holes or air valves or other means are provided for the gradual escape of
air. If desired, however the piston upon the pendent rod and its cylinder may
be dispensed with. It will be noted that no matter when the cut off is effected
the spring is under a constant degree of compression except so far as it is effected
by the inertia of the load, and is therefore always equally effective in closing the
valve with the necessary force which is required for the very early points of cut
off, or for instance when the disengagement of the trip gear takes place before
the valve opens, while at the same time the spring is not excessively compressed
for the later points of cut off thus avoiding excessive noise or concussion in the
dash pot.
The gist of our invention consists in the co-operation of a sliding or rising
weight or load with the spring used to effect the closing of the valve so as to main-
tain the spring under a compressive strain equal to its requirements under vary-
ing points of cut off and so render the same more effective in properly closing the
valve. We do not therefore confine ourselves to the exact arrangement described
as the same may be varied without departing from the spirit of our invention.
Dated this 1at do n
100%
CONT LEIE SPECIFICATION.
Improvements in and connected with Corliss and similar Valves.
We, NORMAN MACBETH and HENRY WOOD, both of the Victoria Foundry,
Bolton, in the County of Lancaster, Engineers, do hereby declare the nature of

page_text: this invention, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement and accompanying
drawings:-
Our said invention relates to improvements in, and connected with Corliss, and
other valves which are actuated by a trip or release gear, as is well understood.
In this type of valve motion, when the valve is released by the trip gear it is
rapidly closed by means of a weight or spring.
The method now generally in use for effecting this when springs are used, is
to connect the valve with a piston working in a cylinder or dash pot. In or con-
nected with the dash pot is à coiled or other form of spring which is partly com-
pressed when the valve is closed and at rest, and is more fully compressed as the
valve is opened. The function of this spring is to effect a rapid closing of the
valve when it is released by the trip motion.
When simple falling weights are used the closing of the valve is too slow to
give the desired sharpness of cut-off.
The method of utilising the compressed spring to effect the closing of the
valve in the old manner is subject to certain disadvantages, for instance, if an
early cut off is required, the spring will not be so much compressed as is the case
with a late cut off, and would therefore not be as strong, although a greater
strength of spring is desirable for the earlier points of cut off than for the later
ones. This is desirable in order to compensate for the inertia of the parts set
in motion in closing the valve, and also as in the case of Corliss valves to overcome
the greater friction caused by working the valve over the lap when the port is
covered.
The object of our invention is to overcome this defect which we do by provid-
ing means whereby the spring may be subjected to a greater amount of com-
pression when required to close the valve at the early points of cut off and to a
less amount of compression at the later points of cut off.
By these means no matter whether the cut off be early or late the spring may
be made always equally effective in causing a rapid and perfect closing of the
valve at the required times.
And in order that our invention may be fully understood we have attached
hereto two sheets of explanatory drawings to which we will now refer.
On Sheet 1,,
Fig. 1 is a side elevation partly in section showing our invention applied to
Corliss valves.
Fig. 2 is an end elevation of Fig. 1 also partly in section.
On Sheet 2,
Fig. 3 shows a modification of our invention.
Referring to Figs. 1 and 2 our invention is shown applied to the inside
valves A A which valves are alternately opened by a detent gear operated by a
reciprocating bar a worked from an excentric in the usual manner. The out-
side valves B B are operated by a separate excentric as usual.
In carrying our invention into effect we provide a dash pot 6 for each inside
valve A which dash pot is secured to the floor or any suitable part of the engine.
Within the dash pot b works a piston c which is provided with a cross pin d
capable of sliding in vertical slots 6' formed in the dash pot b. To the pin d is
secured the rod e connected to the inside valve A. The dash pot 6 is provided
with an air relief valve f of suitable construction to allow for the gradual escape of
air on the descent of the piston as is well known. A washer f¹ of leather or other
resilient material may be secured to the bottom of the piston c to absorb shock
and render the piston noiseless on its contact with the bottom of the dash pot b.
To the pin d are secured links g g the lower ends of which are screwed and
carry adjustably thereon a cross head has more clearly shown in Fig. 2. Mounted
on a pin h secured to the cross head h is a pendent rod i and upon this rod wę
mount a sliding weight or load j.

page_text: The load preferably consists of a number of removable discs of metal mounted
upon a hollow cylindrical carrier k, as shown in the sectional view Fig. 1.
The bottom of the cylinder k, is closed by a removable cover k¹. The pendent
rod i is provided with a piston 7 working within the cylindrical carrier k (Fig. 1).
The rod of the piston is bored out for the reception of the pendent rod i and
works loosely in the cover ¹ of the cylinder k. The lower end of the rod of
the piston is formed with an internal screw thread by which it is secured to the
screwed end of the pendent rod i the piston abutting against a shoulder formed by
the enlarged portion on the pendent rod i and a lock nut m secures the piston in
position. Around the piston rod is disposed a coiled spring n below the load j
and abutting against an adjustable stop o. The sliding load j compresses the
spring, the amount of such compression being varied at will by increasing or
diminishing the number of weights and by operating the adjustable stop o which
is screwed on the rod i and secured by means of the nut p according to the
weight of the load.
As shown in the drawings the rod e is in its lowest position and the valve closed
and at rest. When the valve is opened the piston c is moved in the dash pot b
thus raising the pendent rod i with its sliding load j and compressed spring n.
On
the release of the valve the compressed spring in expanding effects the rapid
closing of the valve. The sliding weight falls down and again compresses the
spring n previous to the succeeding opening of the valve. The piston 7 prevents
the too abrupt descent of the sliding load upon the spring, an air space or cushion q
being provided between the piston and the descending cylindrical carrier k,
tending to bring the load quietly to rest in a position somewhat above or clear of
the internal piston the amount of such clearance being regulated by the adjust-
able stop o. Air valves are provided for the gradual escape of air.
If desired however the piston upon the pendent rod i, and its cylinder k may
be dispensed with as shown in Fig. 3. In this case the load is disposed around
and capable of sliding upon the pendent rod i. We prefer however the arrange-
ment shown in Figs. 1 and 2.
In performing the work done in compressing the spring, the inertia of the
weight or load plays an important part in effecting the desired result, thus when
the valve commences to open the inertia of the load holds it back to some extent
and causes an increased compression of the spring for the early points of cut off.
In a contrary manner the inertia of the load causes it at the later points of cut
off to make a greater length of stroke in rising than the stroke of the adjustable
stop on the pendent rod i thus relieving the spring of its load and consequent
compression to some extent when the valve is released at a point of late cut off.
This effect is peculiarly marked in cases where the valve is as usual opened by
the motion of a revolving excentric, as the motion of the valve and the pendent
rod becomes slower towards the end of the stroke or throw of the excentric, while
at the same time the motion of the weight or load on the spring is increased by
its inertia, thus relieving partially the compression of the spring.
It will be noted that no matter when the cut off is effected the spring is under
a constant degree of compression, except so far as it is effected by the inertia of
the load, and is therefore always equally effective in closing the valve with the
necessary force which is required. for the very early points of cut off, or for
instance when the disengagement of the trip gear takes place before the valve
opens, while at the same time the spring is not excessively compressed for the
later points of cut off, thus avoiding excessive noise or concussion in the dash
pot.
The gist of our invention consists in the co-operation of a sliding or rising
weight or load with the spring used to effect the closing of the valve so as to main-
tain the spring under a compressive strain equal to its requirements under vary-
ing points of cut off and so render the same more effective in properly closing the
valve. We do not therefore confine ourselves to the exact arrangement described
as the same may be varied without departing from the spirit of our invention.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1) As means for closing Corliss and similar valves actuated by trip or release
gear, the employment of a sliding weight or load in conjunction with the spring
used to effect the closing of the valve, whereby the spring is subjected to a greater
amount of compression for closing the valve at the early points of cut off and to
a less amount for the later points of cut off, thus rendering the spring more
effective and responsive to the varying requirements substantially as described
and shown.
2) The general arrangement construction and combination of parts comprising
the improvements in Corliss and other valves actuated by trip or release gear,
substantially as described and illustrated in the drawings.
Dated this 24th day of June 1898.
For the Applicants,
E. K. DUTTON & Co.,
Chartered Patent Agents, 5, John Dalton Street, Manchester.