Improvements in Valve Gear for Duplex Engines for Pumping or other Purposes.
Year: 1894

page_text: Date of Application, 10th Apr., 1894
Complete Specification Left, 10th Jan., 1895-Accepted, 23rd Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Valve Gear for Duplex Engines for Pumping
or other Purposes.
I, AUGUSTUS BEVER, of Dewsbury Foundry, Northgate, Dewsbury in the
County of York, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention of improvements in the arrangement and construction of valve
gear for duplex engines cousists in coupling the two valve spindles belonging to the
two steam cylinders together by means of a vibrating beam or lever, or by means
of a combination of levers usually placed horizontally and in coupling this lever or
these levers to the two levers worked from the piston rod crossheads, as in ordinary
duplex pumping engines, thus obtaining a motion of the valve spindles which is a
combination of the motions of the two crossheads.
Under certain circumstances, which vary according to the lengths of stroke of
the piston rods and valve spindles and the distance of centres of cylinders, I find
it more convenient to have one lever for each valve spindle and couple each such
lever to the two piston rods to obtain the desired combined motion.
11001
Improvements in Valve Gear for Duplex Engines for Pumping
or other Purposes.
I, AUGUSTUS BEVER of Dewsbury Foundry, Northgate, Dewsbury, in the
County of York, 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 of improvements in the arrangement and construction of valve
gear for duplex engines consists in coupling the two valve spindles belonging to the
two steam cylinders together by means of a vibrating beam or lever, or by means
of a combination of levers usually placed horizontally and in coupling this lever or
these levers to the two levers worked from the piston rod crossheads, as in ordinary
duplex pumping engines, thus obtaining a motion of the valve spindles which is a
combination of the motions of the two crossheads.
Under certain circumstances, which vary according to the lengths of stroke of
the piston rods and valve spindles and the distance of centres of cylinders, I find
it more convenient to have one lever for each valve spindle and couple each such
lever to the two piston rods to obtain the desired combined motion.
In order to enable my invention to be thoroughly understood, I will describe the
same with reference to the accompanying drawings in which
are
Figure 1 is an elevation partly in section and Figure 2 is a plan of a duplex
pumping engine fitted with the improved valve gear, and Figures 3 and
diagrams to explain the motion and arrangement of this gear.

page_text: Similar letters of reference indicate similar or corresponding parts throughout
the several figures of the drawings.
Referring to Figures 1 and 2 A A are the steam cylinders, B is the casting
containing the two pumps, one being worked by a rod from each of the steam
cylinders, C C are the piston rods connecting the pistons of the steam cylinders
with those of the pumps; on these piston rods are two small crossbeads or
brackets D, D which are fixed on the rods and reciprocate with the rods, these
are connected by means of short links E, E to swinging levers F, F working on
the centres G G and on these centres are also keyed the short levers H H which
are connected by means of links II to the vibrating lever K K, this lever will
therefore have a compound motion which is a combination of the movement of
both piston rods. The lever K K is coupled to the two valve spindles as shewn.
By this arrangement the slide valve of each cylinder has its motion imparted to
it by the piston rod of the other cylinder, but the motion is controlled and regulated
by that of its own piston.
To describe further the motion of this valve gear I will refer to the diagrams
shewn on Sheet No. 2.
Figure 3 is a diagram of a similar gear to that shewn in Sheet No. 1, Figure 4
being a diagram of a gear in which two vibrating levers are used, one for each
valve spindle. In these diagrams the swinging levers F F are, for the sake of
simplicity, shewn in the same plane as the vibrating levers; L and R are the
centres of the two valve spindles. When the engine is working under normal
conditions, the piston of one cylinder is at the end of its stroke when the piston
of the other cylinder is at half stroke, so that if the piston on the side marked Lis
in position inarked 1 or at the inside end of its stroke the piston on the R side will
be also in position marked 1 or at half stroke and the corresponding position of
the vibrating lever is also marked 1 and it will be seen that the slide valve on the
side marked L is in its extreme forward position; as the piston L moves
from 1 to 2 or half stroke the valve spindle is pushed back to close the back
steam port, but although the piston travels through half the length of its stroke
the valve spindle only travels a short way on account of the motion being counter-
acted by the motion of the piston on the other side, afterwards in the second half
of the stroke the motion of the piston R assists the piston L in moving the valve
so that while the piston travels from 2 to 3 the valve is pushed from position 2 right
over to the full backward position marked 3; this-action repeats itself in the next
stroke and also in the valve on the side R.
In all cases the motion of the valve of each cylinder is retarded by the opposite
cylinder during the first half of the stroke and accelerated during the second half,
the amount of this retarding and accelerating depending on the proportions given
to the various levers forming the valve gear.
In the gear shewn in Figure 4 the action is similar but a separate vibrating lever
is supplied for each cylinder, the lever K 1 being connected to the valve spindle ou
side R and the lever KII to the valve spindle on side L, each lever being
connected with both the swinging levers FF and H Has shewn in the accompanying
diagram.
The object of this invention is to obtain an iniproved motion in the slide valves
of duplex pumps which will enable me to work these pumps at a high piston speed,
also to work them with an early cut-off of steam and to obtain an arrangement
which will cause the motion of one cylinder to govern that of the other by cutting
off the steam earlier if it gets in advance of its proper position.
Having 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) In a duplex engine for pumping or other purposes working the two valve
spindles by means of one vibrating lever which is connected to two swinging levers
worked by the two piston rods as hereinbefore described.

page_text: (2.) The improved valve gear for duplex engines constructed, arranged and
operating substantially as hereinbefore described and represented by Figures 1, 2
and 3 in the accompanying drawings.
(3.) The improved valve gear for duplex engines constructed, arranged and
operating substantially as hereinbefore described and represented by Figure 4.
Dated the 8th day of January 1895.
AUGUSTUS BEVER.