Improvements in Pumping Engines.
Year: 1892

page_text: Date of Application, 3rd May, 1892-Accepted, 4th June, 1892
COMPLETE SPECIFICATION.
Improvements in Pumping Engines.
I, HENRY DAVEY, of 3 Princes Street, Westminster, in the County of
Middlesex, 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 of direct-acting steam pumps,
and a combination of cylinders, pistons, valves, and valve gearing consisting of two
complete engines capable of working together as one machine, or separately as two
distinct machines.
In Fig. 1, a and a' are high pressure cylinders; the annular space 6 and 6'
around the plungers c and c' forming the intermediate cylinders, and d and the
space at the back of the piston d¹ are the low pressure cylinders.
Each of the pistons F and F has a plunger cand c', which plungers are connected
together by the piston rods e. f is a valve worked from the engine through the
rod g, steam is admitted by this valve to the subsidiary cylinder g'. In this
cylinder are placed the piston valves h and 4' which are connected by means of the
rods and to the D slide valves k and k¹.
เ is a cataract, consisting of a cylinder m filled with water or other fluid, and
having a passage leading from one side of the piston to the other regulated by a
plug valve n, a construction well understood.
This cataract regulates the speed of the piston valves h and h', and consequently
that of the D slide valves k and k¹. o is a cushioning valve for the purpose of
retaining some steam in the cylinder towards the end of the stroke.
The engines are connected to the pumps and ¹ by the rods W and W₁
respectively.
Steam being admitted by the valve to the subsidiary cylinder g', through the
pipe p, the valves and h¹ move over, and steam enters the high pressure cylinder a,
through the port q, the intermediate cylinder 6 from the high pressure cylinder a¹,
through the passages q', v, r, and r¹, and the low pressure cylinder d from the
intermediate cylinder & through the ports and s', whilst the exhaust from the low
pressure cylinder d passes away through the passages t and t'.
The cushioning valve o which is worked from the engine through the rod u may
be closed before the end of the stroke by covering the exhaust ports vor vl and
retaining some steam in the cylinder, thus bringing the piston gradually to rest.
L is a governing or cut-off valve, working in the small cylinder M. This valve
is connected to the lever N through the rod O' which receives the combined motion
of the subsidiary cylinder valves h and h' through the spindle i¹ and of the engine
motion through the lever P and rod Q. The lever N is moved into the position
indicated by the dotted line R thus closing the ports and cutting off steam. The
engine being then at the end of the stroke the valves h and are moved over by
the action of the subsidiary cylinder g', thus moving the lever N into the position
indicated by the dotted line T, uncovering the ports and readmitting the steam.
The point of cut off may be varied by moving the end of the rod O' in the slot U
in the lever N, thus causing the valve L to cut off steam earlier or later as the case
may be. The engines may be made to work together or separately. If required
to work together, the lever y of engine No. 2 actuates the levers A and A' through
the shaft z, thus working the small valvef and cushioning valve o of engine No. 1
through the rods and u respectively, whilst the lever y₁ of engine No. 1 actuates
the levers B and B' through the shaft z' and thus works the valves of engine No. 2
in the same manner, through the rods J and K.
If required to work each engine separately and independently, the lever y¹ of

page_text: engine No. 1 actuates the levers D' and D on the shaft z', the rods g and u being
then disconnected from the levers A and A' on the shaft z and connected to the
levers D and D' on the shaft. The shafts z and 2' may be disconnected at the
couplings G and G. Thus each engine works independently by actuating its own
valves.
Having now 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 :-
1st. The combination of the steam cylinders, and the valves k and k³, the
subsidiary cylinder g', the valves and h¹³, the cataract 1, the cushioning valve o,
the connecting rods u and g, the lever y', the rocking shaft z', the levers D and D',
the crosshead H, or other moving part of the engine giving the required motion as
described and illustrated.
2nd. A governing or cut off valve L having a differential motion of the
subsidiary cylinder 9', and of the engine motion, and communicated through the
lever N and enabling steam to be cut off at different parts of the stroke.
3rd. The combination of the two engines by means of the shafts 2 and 2¹ and
levers A, A' and E, E', and D, D' and B, B', so that by connecting the rods u
and g or J and K with either of the levers A, A' and D, D' or E, E¹, and B B',
the engines may be made to work separately or together, as described and
illustrated.
Dated this 2nd day of Mar 1802
HENRY DAVEY.