IMPROVEMENTS IN APPARATUS OR ARRANGEMENTS FOR REGULATING THE SPEED OF MOTIVE-POWER ENGINES WORKED BY STEAM OR OTHER FLUID
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by William Murdoch at the Office
of the Commissioners of Patents, with his Petition, on the 2nd
April 1873.
I, WILLIAM MURDOCH, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN APPARATUS OR ARRANGEMENTS FOR REGULATING THE SPEED OF
MOTIVE-POWER ENGINES WORKED BY STEAM OR OTHER FLUID," to be as follows,
that is to say :-
This Invention has for its object the better and more convenient
regulation of the speed of motive-power engines worked by steam or
other fluid, and it consists according to one modification in combining
with the main engines a small engine or set of small engines of any
convenient type or arrangement, and arranged to actuate the slide valves
(or equivalent parts) of the main engines, that is to say, the valves of
the main engines instead of being worked from the crank shaft of those
engines are to be worked from the crank shaft or from a shaft in gear

page_text: with the crank shaft of the small or governor engines. The work the
governor engines have to do will thus continue practically uniform, so
that these engines will run at a practically uniform rate, so long as the
pressure of the steam or other fluid actuating them remains the same,
whilst it is obvious that the main engines will not be able to run
at a greater speed than that corresponding to the motion of their
valves.
The reversing of the governor engines will have the effect of also
reversing the main engines, so that in large engines there will be
a great reduction in the expence of the gearing required for reversing.
The speed of the small or governor engines may be regulated by a
small governor of any suitable known kind or by arranging a reducing
valve in its steam pipe and loading it to a pressure corresponding to the
desired speed, so that the steam actuating the governor engines may
never exceed that pressure notwithstanding fluctuations in the boiler
pressure.
In a second modification the governor engines are arranged to
drive a wheel, boss, or tube, that is loose on the crank shaft of the
main engines or on a shaft geared thereto, and whenever the shaft
turns at a different speed from the wheel, boss, or tube it acts by
means of a helical groove and feather or equivalent detail to produce
a movement along the shaft, and such movement is transmitted by
levers and links to throttle valves in the steam and exhaust pipes of the
main engines or to a single throttle valve in either the exhaust or the
steam pipe.
In a third modification the arrangements of the first and second
modifications are combined and will secure a satisfactory regulation in
cases wherein it is desirable to maintain a uniform speed notwith-
standing great fluctuations in the resistance to be overcome by the main
engines.
In a fourth modification steam valves of the ordinary kind aro worked
by the main engines whilst cut-off valves working in connection with
such steam valves are actuated by the governor engines, and in this case
it is also preferred to have the exhaust of the main engines controlled by
valves worked by the governor engines.

page_text: In a fifth modification the admission of steam to the cylinders of the
main engines is controlled by valves worked entirely by the main
engines (excepting a throttle valve in the steam pipe), whilst the
exhaust is controlled by valves worked by the governor engines.