A NEW OR IMPROVED CONSTRUCTION OF MOTIVE-POWER ENGINE
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by John Neil and James Kerry at the
Office of the Commissioners of Patents on the 30th May 1881.
JOHN NEIL, of Glasgow, in the County of Lanark, and JAMES KERR, of Greenock,
in the County of Renfrew, North Britain. A NEW OR IMPROVED CONSTRUCTION
OF MOTIVE-POWER ENGINE."
"
This said Invention has reference to a new or improved general construction or
arrangement and combination of the parts of a steam or other pressure-fluid
motive-power engine or motor, which possesses several advantages over other
motive-power engines heretofore in use from its special low compact and self
contained portability in construction with little liability to derangement, and
power of self lubrication of the main bearing and working parts, and consequent
cheapness of first cost, and expense in working and keeping up.
The particular construction and essential novelty of this engine (forming the
subject of this Invention) consist all as follows in forming the motive-fluid
pressure cylinder rather more than three times the length of the "stroke" of the
engine motion of the piston. This cylinder, which is made very long (as from
three to four or more times the length of the stroke of pistons), has only the
parallel working parts bored out at each end rather longer than the "stroke,"
into which separate pistons are fitted to work with steam-tight metallic or other
packing, and with close cover screwed on at each end, for the steam or other
pressure fluid to be alternately admitted and exhausted from each opposite end of
the cylinder between the close covers and the pistons, while the crank shaft is
fitted to work through tightening up bushes or trunnion like bearings fitted on the
sides and intermediate middle part of the cylinder. The two pistons are secured
together by four long rods or other equivalent means to act simultaneously as one
long piston, with sufficient space laterally between the rods to allow the main
driving crank shaft and its double or single crank to rotate between them, and
sufficient length or distance to allow room for the connecting-rod being jointed to
the inner side of one of the pistons and crank on one side, and have the crank to
clear the piston on the other side.

page_text: This cylinder would therefore form the main frame of the engine, and, when
desired, for a horizontal engine would have broad flanges, or it might be strong
crossed webbed and flanged stools at each end for securing it to any ordinary suitable
foundation or wall. And it would have one or both the neck bearings of the crank
shaft formed or fitted in removable plate brackets secured steam-tight over recesses
in the sides of the middle part of the cylinder for inserting the crank from one
side. A manhole with portable door or cover would preferably be fitted in the
cylinder above the crank for convenience of coupling and uncoupling the connecting
rod, and a small peep hole with removable plug would also be fitted in this central
cover or part of the cylinder for the insertion of a box screw-key or other tool for
tightening up the connecting rod bushes. The steam is admitted to the one end of
the cylinder while it is being exhausted from the other, so that an ordinary single
short or long slide valve, or short one at each end, would answer for this engine.
It is however preferred to have a single cylindrical valve in the middle for small
engines; or for larger sizes, to save the steam which would be lost by long ports, two
such valves; one would be fitted in a separate steel casing at each end of the
cylinder, where in this case there would be a steam port at the extreme end, and
an exhaust port and chamber inside this. These valves would be made rather
longer than the ports in the cylinder, have a central exhaust port in the centre,
and a face and "cover" at each side circumferentially with open space round to
the back in the middle part to admit the steam at the outer end while covering the
exhaust port on the inside. and these valves would be fitted to oscillate in their
bored casings over the port face part, so as to keep always steam tight, and be
worked by a flat spindle in a slotted hole through them, the outer end of which
would work out through a stuffing box, so that each valve could be worked by a
lever and rod direct from an eccentric for each on the crank shaft; or when the
valve levers were set and coupled together by a rod, both valves could be worked
by an eccentric and rod. The slide valves either on centre or ends of cylinder can
in both cases be worked with link motion with two eccentrics, or with one loose
eccentric on crank shaft. Springs may be fitted between the lower edge of the
valve spindle and its slot to keep the working faces of the valve and its casing
steam-tight around the ports, or the pressure of steam on the back of valve may
do this.
The exhaust ports (or their chamber of the steam casing or face-plate of cylinder)
would be in direct communication with the close central chamber of the cylinder
between the pistons, so that as it was cooled or condensed in this chamber it would
be used for moistening and lubricating the working surfaces of the cylinders and
pistons, and the main bush bearings of the crank shaft, and the crank, and its
bushes, and connecting-rod joints, proper ducts and recesses being fitted and formed
in these parts to conduct the wet steam thereto for the purpose of keeping the
working surfaces smooth and reducing friction. And when found desirable oil or
melted tallow could be blown through the engine with the steam to assist in the
perfect lubrication of the valves and the other main working parts.
This new construction of engine is suitable for working on the single or compound
high pressure expansive principle with double cylinders, such as the one described,
the large or second cylinder getting the steam from the exhaust chamber of the first
cylinder, with a crank for each cylinder on the same crank-shaft; or as a compound
condensing engine, with surface or other condenser connected with the exhaust
central space of the larger low-pressure cylinder.
The high pressure cylinder may be worked with an independent crank shaft
from the low pressure cylinder, as for being fitted to drive the twin screws of a
steam boat. In this case there would require to be a branch exhaust pipe from
the high pressure cylinder with cock or valve for opening to the atmosphere when
the high pressure engine was working separate or alone.
In high pressure steam engines of this construction the central exhaust steam
space of the cylinder might be wholly or partially jacketed to form a hot feed water
chamber for feeding into the boiler after being heated by the exhaust steam.

page_text: This new engine from its low compact construction would be very suitable for
motive power purposes in confined spaces and low-roofed places, such as for driving
the screw or other propellers near the lower part of launches or yachts, and other
small steam vessels, and for driving "coal-cutting," "rock-boring," pumping, and
winding machines in pits and mines. Also for driving portable, tramway, and
traction engines or carriages, and portable hoisting or excavating machines or
wheeled carriages, or other machines where there is little room for the motive
engines.