valve gear for direct acting steam pumps
Year: 1885

page_text: We GEORGE FLETCHER, of Masson Works, Litchurch, in the county of Derby,
Engineer, and WILLIAM PRICE ABELL, of 408, City Road, Old Trafford, Manchester,
in the county of Lancaster, Engineer do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in valve gear for direct acting steam
pumps, steam engines, rock drills, organ blowers, hydraulic motors, steam hammers,
gas engines and the like.
In direct acting pumps which do not allow of the employment of an eccentric
the steam admission valve has usually been moved either partly or wholly through
its stroke by a piston working in an auxiliary steam cylinder, the valve of the said
auxiliary cylinder being actuated by a lever or tappet arrangement. This occasions
a waste of steam through the valves and cylinder besides using a cylinder full of
steam at each stroke, to move the main valve alone; and as the cylinder must be
made large enough to move the main valve under all conditions of friction and
lubrication, it follows that when the valve is working under favorable conditions
of lubrication there is a great excess of power and steam used to move the valve at
each stroke.
The above arrangements of steam moved valves have been rendered necessary
through the want of an arrangement that will give the valve a direct outside
motion.
The object of our invention is to provide such an arrangement which will give
the main steam valve its desired motion without the intervention of an eccentric
or auxiliary steam cylinder. For this purpose we connect the pump at a suitable
distance from the steam cylinder in the ordinary manner the said cylinder being
fitted with an ordinary D slide valve, and valve rod projecting beyond the steam
chest, this rod we connect by means of a link to a lever, the other end of which is
pinned to the piston rod so that it moves with it; between the piston rod and the
slide valve connecting rod we arrange studs or pins in such a manner that they act
as fulcrums for the aforementioned lever at certain positions of the stroke thus
giving opposite motions to its opposite ends, this takes place more particularly just
as the piston is completing its stroke thus giving the valve a suitable cut-off
motion and also the necessary lead, this cut off can be regulated to suit the work
the pump has to perform by altering the position of the said pins,

page_text: When it is required to render the cut-off automatic, instead of using fixed
fulcrum pins the afore-mentioned lever is connected by links to a pendulum the
chronometric vibration of which places the links in such a position that any
variation between the speed of the pump and the vibration of the pendulum will
alter the point of steam cut-off. Or the cut off pins may be connected with
cataracts which will also adjust their position and thus give an automatic cut-off
varying with the speed of the pump.
In order to complete the valve motion and fully open the ports the valve
requires a continuation of the motion already communicated to it, to give full
steam on the return stroke; for this purpose we fit to that end of the herein before
described lever which is farthest. from the piston rod, a moveable or a fixed pin
which takes hold or is taken hold of by a plate suitably fixed or by one of two
latches which will release the aforesaid pin on its reaching a position which can be
regulated to suit the port opening. By these means we not only obtain a motion
direct from the piston rod by using one outside lever, but the valve which is of the
ordinary D kind, only absorbs the actual amount of power required to move it at
each stroke.
Our invention is not only applicable to pumps as herein before described but also
to steam engines, rock drills, organ blowers, hydraulic motors, steam hammers, gas
engines and the like.
Improvements in
Coal
We GEORGE FLETCHER, of Masson Works, Litchurch, in the county of Derby,
Engineer, and WILLIAM PRICE ABELL, of 408, City Road, Old Trafford, Manchester,
in the county of Lancaster, Engineer, do hereby declare the nature of this inven-
tion 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 improvements in valve gear for direct acting steam
pumps, steam engines, rock drills, organ blowers, hydraulic motors, steam hammers,
gas engines and the like.
In direct acting pumps which do not allow of the employment of an eccentric
the steam admission valve has usually been moved either partly or wholly through
its stroke by a piston working in an auxiliary steam cylinder, the valve of the
said auxiliary cylinder being actuated by a lever or tappet arrangement. This]

page_text: occasion's a waste of steam through the valves and cylinder besides using a cylinder
full of steam at each stroke, to move the main valve alone; and as the cylinder;
must be made large enough to move the main valve under all conditions of friction
and lubrication, it follows that when the valve is working under favorable
conditions of lubrication there is a great excess of power and steam used to move
the valve at each stroke.
The above arrangements of steam moved valves have been rendered necessary
through the want of an arrangement that will give the valve a direct outside
motion.
The object of our invention is to provide such an arrangement which will give
the main steam valve it's desired motion without the intervention of an eccentric
or auxiliary steam cylinder.
In order to enable our invention to be fully understood we will describe the
same by reference to the accompanying drawing in which figure 1 is a longitudinal
elevation partly in section of a direct acting steam pump provided with valve gear
constructed according to our invention; figure 2 is a cross section of figure 1;
figures 3, 4 and 5 are similar views to figure 1 but with the cylinder valve and
pump removed and illustrating slightly modified arrangements of our improved,
valve gear. Similar letters in all the figures represent similar parts.
:
We will first describe our invention by reference to figures 1 and 2.
For the purpose of our invention we connect the pump h, at a suitable distance
from the steam cylinder a, by means of framing g, in the ordinary manner, the said,
cylinder being fitted with an ordinary D slide valve b, and a valve rod c, projecting
beyond the steam chest d. The rod c, we connect by means of a link B to a
lever C; the other end of the lever C, being pinned to the piston rod e, by means
of a projection f, thereon in such a manner that it moves with it; between the
piston rod e, and the slide valve connecting rod B we fix studs or pins A, A on the
frame g, connecting the cylinder a, with the pump the studs or pins A, A serving,
as fulcra for the lever C, at certain positions of the stroke of the piston i, thereby
giving motion in opposite directions to the opposite ends of the said lever.
takes place more particularly just as the piston 2, is completing its stroke and gives
the valve b, a suitable cut off motion and also the necessary lead. This cut off can
be regulated to suit the work the pump h, has to perform by altering the position
of the pins or fulcra A, A.
This
When it is required to render the cut-off automatic, instead of using fixed
fulcrum pins A, A as hereinbefore described and shewn in figures 1 and 2 the
lever C is connected as shewn in figure 4 by links (one of which is represented
at j) to a pendulum D, the chronometric vibration of which places the links in
such a position that any variation between the speed of the pump and the
vibration of the pendulum will alter the point of steam cut off.
Or the cut off pins or their equivalents may be connected with a cataract
governor as shown at E in figure 3 in which the pins A are shewn replaced by a
slotted bar on the spindle or rod of the cataract governor which will also adjust
the position of the pins or their equivalents and thus give an automatic cut off
varying with the speed of the pump.
In order to complete the valve motion and fully open the steam ports the
valve b, figure 1 requires a continuation of the motion already communicated to it,
in order to give full steam on the return stroke. For this purpose to the end of
the lever C farthest from the piston rod, is fitted either a moveable or a fixed pin F
which presses against a plate or cam G suitably fixed as shewn in figures 1 to 4
to the frame g, or is taken hold of by one of two latches G, G, as shewn in figure 5
which plates or latches release the pin F, on its reaching a position which can
be regulated to suit the port opening by employing different shaped plates or
cams G, figures 1 to 4 or by altering the position of the latches G, G, figure 5.
By these means we not only obtain a motion direct from the piston rod e, by
using an outside lever C, but the valve b, which is of the ordinary D kind, only
absorbs the actual amount of power required to move it at each stroke,

page_text: Our invention is not only applicable to pumps as hereinbefore described but also
to steam engines, rock drills, organ blowers, hydraulic motors, steam hammers, gas
engines, and the like.
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. The use in valve gear of the pins A, A or their equivalents for giving cut off
and lead to the main valve substantially as herein before described and represented
in figures 1, 2 and 5 of the accompanying drawing.
2. The automatic arrangement for moving the said pins or their equivalents
substantially as hereinbefore described and represented in figure 3 of the accom-
panying drawing.
3. The use in valve gear of a pendulum operating substantially in the manner
herein described and shewn in figure 4 of the accompanying drawing.
4. The use in valve gear of the plate or cam G herein described and shewn in
figures 1, 2, 3 and 4 or the catches G, G herein described and shewn in figure 5
operating substantially in the manner and for the purpose set forth.
5. The herein described lever arranged to move bodily in the same direction as
the piston rod at the commencement of each stroke as and for the purpose herein-
before described and represented in figures 1, 2, 3, 4 and 5 of the accompanying
drawing.
6. The use in valve gear of a lever which at the completion of the stroke of the
piston vibrates on a fulcrum thereby causing opposite directions of motion to be
given to the opposite ends of the lever which at the commencement of the stroke
moves bodily in the direction of motion of the piston substantially as and for the
purpose herein before described and represented in figures 1, 2, 3, 4 and 5 of the
accompanying drawing.