Year: 1886

page_text: I, FREDERICK WILLIAM STOKER, of Bylton Villa, Jarrow, in the County of
Durham, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates more especially to rotative engines intended to work
against very high continuous columns and at high velocities but it is equally
applicable to slow speed engines.
It consists in applying to a crank on main shaft-at right angles to the main
crank an auxiliary engine the function of which is to enable the main engine to
turn the "dead" centres slowly, irrespective of the speed at which it may be
moving during other portions of its stroke.
The valves by which steam is admitted to each end of the auxiliary cylinder are
entirely separate and under separate control, as to the admission to each end, so as
to regulate the power to be transmitted to the main engine by its requirements.
In conjunction with the auxiliary engine I propose to apply separate expansion
valves to the cylinder or cylinders of the main engine so that the admission of
eteam may be regulated to the requirements of working at low or high speeds
respectively.
The combination of the auxiliary engine with the expansion valves on the
cylinder or cylinders of the main engine is an important feature, because the need
for the assistance of the auxiliary power to turn the "dead" centres depends upon
the speed of the main engine, being greater when working slowly and less when
working at higher speeds when the momentum of the revolving parts is more
effective and the auxiliary engine and expansion valves thus become the one the
complement of the other in varying proportions according to the speed at which
the main engine is working.
W. LLOYD WISE;
46, Lincoln's Inn Fields, London, W.C., .
Agent for the Applicant.

page_text: I FREDERICK WILLIAM STOKER of Bylton Villa, Jarrow in the County of
Durham, 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 relates more especially to rotative pumping engines intended to
work against very high continuous columns and at high velocities, but it is equally
applicable to slow speed engines.
It consists in applying to a crank on main-shaft-at right angles to the main
crank an auxiliary engine the function of which is to enable the main engine to
turn the "dead" centres slowly, irrespective of the speed at which it may be
moving during other portions of its stroke.
The valves by which steam is admitted to each end of the auxiliary cylinder
are entirely separate, and under separate control as to the admission to each
end, so as to regulate the power to be transmitted to the main engine by its
requirements.
In conjunction with the auxiliary engine I propose preferably to apply separate
expansion valves to the cylinder or cylinders of the main engine actuated by an
eccentric or eccentrics on the main shaft and adjustable by hand gear so that the
points of cut off in the said cylinder or cylinders may be regulated to the require-
ments of working at low or high speeds respectively.
These adjustable expansion valves controlling the speed of the main engine in
conjunction with the auxiliary engine constitute an important feature, because the
need for the assistance of the auxiliary power to turn the "dead" centres depends
upon and is proportioned to the speed of the main engine, being greater when
working slowly and less when working at higher speeds, when the momentum of
the revolving parts is more effective and the auxiliary engine and expansion
valves thus become the one the complement of the other, in varying proportions,
according to the speed at which the main engine is working.
Although separate expansion valves on the cylinder or cylinders of the main
engine will generally be preferable, they are not indispensible, as the main valve
or valves may be so proportioned or arranged as to admit of such variations by link
motion or other suitable gear, as to sufficiently control the admission and cut-off in
the main cylinders at various speeds.
It will be seen that the auxiliary engine, while fulfilling the functions of a fly
wheel in carrying the main engine over the "dead" centres, has the following
advantages:
That whatever may be the speed of the main engine crank, between the ends of
the stroke, it can be caused to turn the dead centres very slowly the column in
the pump thus coming gently to rest and being gently put into motion on the
succeeding stroke.
The separate valves on the auxiliary engine enable the work of assistance to the
main engine not only to be proportioned to the requirements of high or low speeds,
but also to the requirements in turning one or the other "dead" centre.

page_text: DESCRIPTION OF DRAWING.
On the accompanying drawing I illustrate my invention applied to a single
horizontal compound pumping engine, the high pressure cylinder only being shewn
with the piston rod continuing through to the low pressure cylinder, the main
engine being at half stroke and the auxiliary engine at one end of its stroke.
A is the high pressure cylinder fixed on bed-plate B. C is the piston rod
attached to crosshead D at front end and continuing backward to piston of low
pressure cylinder. E is the connecting rod. F the main crank on shaft G, the
other end of which carries the auxiliary crank H, to which the connecting rod J of
auxiliary engine is attached. K is the steam branch on valve chest of main engine
containing the main valve and expansion valve on back. L is the rod of main
valve extending backward and connected by a coupling M with the valve rod of
the low pressure cylinder. N is the rod of expansion valve fitted with a hand
nut O by means of which the expansion valve can be adjusted on a right and left
hand screw to vary the points of cutting off the steam, while the engine is at work.
These valves are worked by separate eccentrics on main shaft. P is the exhaust
steam pipe to low pressure cylinder. The auxiliary engine Q is fitted at each end
with separate steam chests R R¹ in each of which is a valve worked by one spindle S
by the eccentric T-U U₁ are hand regulating valves on steam chests R R¹ by
means of which the admission of steam through the branch pipe V from boiler can
be adapted to the requirements of the main engine. W is the exhaust branch from
auxiliary cylinder.
Separate exhaust pipes can be used when required with valves similar to the
steam admission valves U U', for the purpose of regulating the pressure on the
exhaust side of the piston.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
First. In rotative pumping engines the application of an auxiliary engine to a
crank on the shaft of main engine, at right angles to the main crank, the cylinder
of such auxiliary engine having separate steam chests and valves with means for
controlling and regulating the admission of steam to each end; with the objects
herein before set forth, constructed and operating substantially as described and
shewn.
Second. The rotative compound pumping engine comprising the main engine
with high and low pressure cylinders-the former fitted with a separate variable
expansion valve-pistons, piston rods, connecting rod, main crank and shaft; in
combination with an auxiliary engine attached to a separate crank, the whole
constructed and operating substantially as described and, as to the main engine in
part shewn.
Dated the 18th day of October 1886.
Witness:
T. J. DANSON,
Newcastle upon Tyne.
F. W. STOKER.