IMPROVEMENTS IN STEAM ENGINES, PARTLY APPLICABLE TO OTHER ENGINES WORKED BY FLUID PRESSURE
Year: 1878

page_text: LETTERS PATENT to Thomas Charles Watts, of Leadenhall Street, in the City
of London, Engineer, for the Invention of "IMPROVEMENTS IN STEAM ENGINES,
PARTLY APPLICABLE TO OTHER ENGINES WORKED BY FLUID PRESSURE."
Sealed the 24th June 1879, and dated the 31st December 1878.
PROVISIONAL SPECIFICATION left by the said Thomas Charles Watts at
the Office of the Commissioners of Patents on the 31st December 1878.
"
THOMAS CHARLES WATTS, of Leadenhall Street, in the City of London, Engineer.
IMPROVEMENTS IN STEAM ENGINES, PARTLY APPLICABLE TO OTHER ENGINES
WORKED BY FLUID PRESSURE."
These improvements relate to engines of that type or class in which the pistons
or trunks receive pressure in one direction only, and are termed single-acting
engines. I combine all the advantages of the engines described in the Specification
of my former Letters Patent, dated 8th November, A.D. 1877, No. 4165, avoiding
long steam-passages and stuffing boxes, and diminishing the number of steam-joints
and adjustable bearings, and other parts.
The said improvements consist principally in the valve arrangements and in an
automatic expansion gear, whereby I ensure great economy and smoothness of
working.
I prefer to employ an independent valve to each cylinder, which valve is placed
on its side, so that each cylinder may be independent of the other in every respect,
by which arrangement (as will be obvious) any number of cylinders can be employed
in any desired position, and with cranks at any angle to each other.
The valve stem passes from each valve down through the exhaust-chamber into
the casing or base containing the crank-shaft. On the said crank-shaft I place
or fix suitable cams or excentrics, or I cast or otherwise secure them on the crank-
arms.
These cams or excentrics raise or lower the valve stem and vary the cut-off (by
connection with the governors or otherwise) by the following arrangement, that is

page_text: to say I place in a convenient position a shaft or spindle connected to the gear of
each valve by a small link or fork; from the end of this fork is suspended a lever,
one point of which is preferably furnished with an anti-friction roller or other equi-
valent device, which is in contact with the said cam or excentric; another point of
the lever's surface is in contact with the end of the valve stem. To avoid adjustable
bearings in this valve gear I keep the whole of the working parts under compres-
sion, preferably by employing a piston valve, and utilizing the steam-pressure on the
top of the said valve; but springs may be employed for this purpose in addition to
or instead of steam pressure.
When an ordinary slide-valve is employed, the pressure acts in both directions.
By maintaining pressure in one direction it is obvious that I can employ a cam of
such shape as will cause a quicker opening and closing of the steam and exhaust
ports than would be practicable with an ordinary excentric.
The automatic cut-off apparatus consists in the arrangement of the governor to
raise or lower the hereinbefore mentioned fork or link attached to the aforesaid shaft
or spindle, thereby consequently altering the points of contact of the lever with the
said cam and valve stem. By the proper arrangement of these different points of
suspension and of the said shaft or spindle operated by the governor or otherwise, I
produce a peculiar motion of the valve, enabling me to fully open the steam and
exhaust ports, whether the cut off be 1% or 7% of the stroke; and a quick or sharp
opening and closing of the valves is obtained by the peculiar formation of the afore-
Baid cam.
By a slight modification these engines are made reversible. The said valves may
be placed between the cylinders, but such an arrangement is not desirable.
In adapting my Invention to steam vessels and for like purposes, I prefer to place
two cylinders on each side at any desired angle, and for the sake of compactness
arranged so that they receive the smoke-box end of a boiler of locomotive form
between them.
In some instances to make the engine very compact I avoid the necessity of con-
necting rods by arranging the ends of the pistons in such manner that they act
directly on the crank without the intervention of such connecting rods, the pistons
being provided with sliding pieces or rollers, which also act as crank pin bearings.
In compounding these engines I prefer to employ four cylinders with cranks at
right angles, that is to say, I use two high and two low pressure cylinders, and I
arrange the valve chambers in such a manner that each high-pressure cylinder
exhausts into the adjacent low-pressure cylinder, and thence to the atmosphere or
condenser; or the piston of the high and low pressure cylinders can be connected
in a similar manner to that described in the Specification of my said former Letters
Patent.
When the automatic expansion arrangement is not applied, the said valve gear
may be much simplified.
My said improvements may be adapted for engines worked by air, water, or other
fluid pressure by adopting such modifications as will be readily understood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Charles Watts in the Great Seal Patent Office on the 30th
June 1879.
THOMAS CHARLES WATTS, of Leadenhall Street, in the City of London, Engineer.
"IMPROVEMENTS IN STEAM-ENGINES, PARTLY APPLICABLE TO OTHER ENGINES
WORKED BY FLUID PRESSURE.”
These improvements relate to engines of that type or class in which the pistons
or trunks receive pressure in one direction only, and termed single-acting engines,
such as those described in the Specification of my former Letters Patent, dated 8th
November, AD. 1877, No. 4165.
The said improvements consist principally in automatic expansion-apparatus,
whereby I ensure great economy and smoothness of working in single-acting
engines.
I prefer to employ a separate valve to each cylinder, so arranged that all of the
cylinders may be independent of each other in every respect; by this arrangement
(as will be obvious) any number of cylinders can be employed in any desired position
and with cranks at any angle to each other in one engine.
In the accompanying Drawings I have illustrated the application of my Inven-
tion to a three-cylinder single-acting engine, but it will be understood that I may
adapt the same with equal advantage to engines with any number of cylinders.
Figure 1 is a plan.
Figure 2 is an end elevation.
Figures 3 and 4 are vertical sections on the lines x, x, and y, y, Figure 1.
Figure 5 illustrates a modification of a portion of my improved mechanism.
Like letters indicate the same parts throughout the Drawings.
A is a strong bed base or stand upon or in which the parts of the engine are
firmly supported; a, a, a, are the three cylinders fitted with pistons b; c, c, c, are the
cranks; and d, d, d, the connecting rods extending directly from the pistons to the
said cranks.
I provide each cylinder with a valve e, which is preferably of a cylindrical form,
as shewn, and which works in a case or chest e* at the side of the cylinder.
The valve stem e' passes from each valve down through the case or chamber e*
into the bed or base A containing the cranks c. On the crank-shaft c¹ I place in
combination with each valve a cam g; or I may cast or otherwise secure one of the
said cams on an arm of each crank.
The said cam operates the valve e and varies the cut-off by the following arrange-
ment, that is to say I place in a convenient position a rocking shaft provided
with three arms or levers i, and each arm i is connected by a small link or fork j to
one of the valve-stems or rods e', as clearly shewn in Figures 3 and 4, and the said
link is preferably furnished with an anti-friction roller k or other equivalent device,
which works in contact with the said cam, as shewn in Figure 3.
To avoid the necessity for adjustable bearings or other devices ordinarily used to
compensate for the wearing of the working parts of the valve-gear, I keep the whole
of the working parts under pressure or compression endwise, preferably by
employing a piston valve e, as shewn, and utilizing the steam pressure on the top
of the said valve; but springs may be employed for this purpose in addition to or
instead of steam pressure.
When an ordinary slide-valve is employed, the endwise pressure may be obtained
by the aid of a piston-valve or by a spring or springs.
By maintaining this pressure in an endwise direction it is obvious that I can

page_text: employ a cam of a shape that will cause a quicker opening and closing of the steam
and exhaust ports than would be practicable with an ordinary excentric.
The part of my Invention relating to the automatic cut-off consists in the arrange-
ment of the governor in combination with the shaft h in such a manner that the
said governor will move the said shaft, and thereby raise or lower the fork or link j
consequently altering the points of contact of the said link or its friction-roller with
the said cam, so that the time of the action of the latter on the said link will be
varied, and the time of movement of the valve will vary accordingly. The con-
nection of the governor with the shaft h is effected by a forked lever fixed on the
shaft h, and extending therefrom to a sleevo 12 on the governor-spindle.
With the cam g shaped as shewn, and the said cam and other parts of the expan-
sion gear properly arranged, as described, I obtain a peculiar motion of the valve,
whereby the same will fully open the steam and exhaust ports to cut off steam at
any part from 1/8th to 7th of the stroke, and there will be a quick or sharp opening
and closing of the said valve.
By a slight modification of the above described parts these engines may be made
reversible. The said valves may be placed between the cylinders, but such an
arrangement is not so advantageous as that above described.
To increase the range of the governor's action on the valve e I employ the modi-
fication illustrated in Figure 5, that is to say, I so arrange the forked lever l¹
through which the governor acts on the rocking shaft h that the governor-spindle
is midway or nearly so between the fulcrum 13 of the said lever and its extremity,
which is connected by the link with the arm h¹ on the rock-shaft h.
In adapting my Invention to steam-vessels and for like purposes, I prefer to
place two cylinders on each side of the crank-shaft at any desired angle, and for
the sake of compactness they are so arranged that they may receive between
them the smoke-box end of a boiler of locomotive form.
In some instances to make the engine very compact I arrange the ends of the
pistons in such manner that they act directly on the crank without the inter-
vention of connecting rods, the pistons being provided with sliding pieces or
rollers.
In applying my Invention to compound or high and low pressure engines of the
class herein described, I prefer to employ four cylinders with cranks at right angles
to each other, that is to say, I use two high and two low pressure cylinders, and I
arrange the valve-chambers in such a manner that each high pressure cylinder
exhausts into the adjacent low pressure cylinder, and thence into the atmosphere or
condenser; or the pistons of the high and low pressure cylinders can be connected
in a similar manner to that described in the Specification of my said former Letters
Patent.
When the means for obtaining automatic expansion are not employed, it will be
seen that the said valve gear will be very simple, and the adjustment of the parts
to vary or alter the cut-off will be effected by hand.
My said improvements may be adapted for engines worked by air, water, or other
fluid pressure by adopting such modifications as will be obvious to those familiar
with the construction and working of such engines.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it understood that I claim,-
First. In a single acting engine, that is to say, an engine in which the steam acts
on the piston or pistons in one direction only, the employment in combination with
a piston-valve or other suitable valve of the apparatus or mechanism by which a
cam on the crank shaft operates the valve while the same is acted upon by steam or
other pressure, substantially as and for the purpose specified.
Second. The combination of the governor with the said valve gear or mechanism
to form an automatic expansion or cut off device, substantially as set forth.
Third. In combination with the said valve-gear, the mechanism shewn in Figure 5

page_text: for increasing the range or extent of the governor's action on the same, substantially
as and for the purpose specified.
In witness whereof, I, the said Thomas Charles Watts, have hereunto set
my hand and seal, this Thirtieth day of June, in the year of our Lord One
thousand eight hundred and seventy-nine.
Witness,
H. H. LAKE,
8, Southampton Buildings,
London.
THOMAS C. WATTS. (LS.)