IMPROVEMENTS IN STEAM ENGINES
Year: 1884

page_text: We, HENRY HERMAN WESTINGHOUSE and ARTHUR GEORGE BROWN, of Liberty
Avenue and Twenty fifth Street, Pittsburgh, in the County of Allegheny, State of
Pennsylvania, and United States of America, and HARRIS TABOR of 187 Sandusky
Street, Allegheny, in the County of Allegheny, State of Pennsylvania, and United
States of America, Mechanical Engineers, do hereby declare the nature of our
Invention for IMPROVEMENTS IN STEAM ENGINES, and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :—
Our Invention relates to steam engines of the class having two vertical single
acting cylinders, the pistons of which are connected to opposite crank pins and
are governed by a common main or distribution valve, as exemplified in Letters
Patent of the United States No. 240,482, granted and issued to H. H. Westinghouse,
under date of April 19, 1881. It is the object of our Invention to provide a
simple, durable, and effective automatic cut off engine, embodying in connection
with the general features of construction above mentioned, novel and improved
means for effecting regulation of speed by variations in degree of expansion,
balancing the weight of moving parts of valve and regulating mechanism, preventing
steam leakage between the distribution valve and its case, maintaining continuous
lubrication during operation, and relieving the cylinders from water of condensation
which may gain access thereto. The improvements claimed are hereinafter fully
set forth.
In the accompanying Drawings: Figure 1 is a vertical, longitudinal, central
section through a steam engine embodying our Invention, at the line y, y, of
Fig. 2; Fig. 2, a vertical transverse section through the same at the line x, x,
of Fig. 1; Fig. 3, a horizontal section at the line 2, 2, of Fig. 2; Fig. 4, a vertical
section, in perspective, and on an enlarged scale, through one of the crank shaft
bearings; Fig. 5, a vertical longitudinal central section through the main valve;
Fig. 6, a transverse section through the same at the line w, w, of Fig. 5; Fig. 7, a
longitudinal section, on an enlarged scale, through a portion of the main valve,
Fig. 8, a view in perspective, of one of the packing rings of the main valve,
detached; Fig. 9, a face view, in elevation, and on an enlarged scale, of the
governor, as seen from the right of Fig. 1; Fig. 10, a side view, in elevation, of
the same; Fig. 11, a face view of the same, as seen from the left of Fig. 1; Fig. 12,
a vertical section through the same, at the line v, v, of Fig. 9; Fig. 13, a partial

page_text: section through the same, at the line t, t, of Fig. 9; Fig. 14, a central transverse
section, on an enlarged scale, through one of the cylinder heads, detached, and;
Fig. 15, a plan or top view of the same.
In the practice of our Invention, two vertical single acting steam cylinders 1, 1,
are secured to the top of a crank case 2, upon opposite sides of an interposed
valve chamber 3, the axis of which is inclined at a slight angle relatively to the
central plane of the cylinders 1, 1. The crank case 2, serves as the bed or support
. of the engine, and also as a tank or receptacle for the lubricating material of the
crank pins and the journals of the crank shaft 4, which rotates in bearings 5, 5,
secured in the ends of the case 2. Access to the cranks may be had, when
required, by the removal of a bonnet 6, on the side of the crank case, and
additional support is afforded to the crank shaft by a centre bearing 7. The
cylinders 1, 1, are open at their lower ends and are fitted with long pistons 8, 8,
of the trunk class, which are coupled by connecting rods 9, 9, with crank pins set
oppositely, or at an angle of 180 degrees, upon a pair of double cranks 10, 10, on
the crank shaft 4. Steam is supplied to the valve chamber 3, by a proper steam
pipe connected to the opening or nozzle 11 therein, and is admitted to and
exhausted from the cylinder spaces above the pistons 8, by a main or distribution
valve 12, which is composed of an upper piston 38, and a lower piston 39, connected
by a hollow or tubular body portion, and is reciprocated in the valve chamber 3,
so as to open, by the movements of its end pistons, ports 13, 14, leading from the
valve chamber to the upper ends of the cylinders 1, 1, alternately to the steam
supply nozzle 11, and to a lower exhaust passage 15, in the valve chamber, to
which the exhaust pipe is connected. The valve 12, is secured upon a valve
stem 16, the lower end of which carries a packed guide piston 17, which works
in an open ended guide cylinder 18, projecting downwardly from a transverse
partition within the chamber 3, and is coupled, by an eccentric rod 19, to the
strap 20, of an eccentric 21, on the crank shaft 4.
The construction of the engine, in the particulars above set forth, which accords
generally with that of Letters Patent No. 240,842 aforesaid, is not claimed as of
our present Invention, the specific features of improvement of which, as applied in
an engine of such character, will now be severally described.
Referring first to the distribution valve 12, and its operating mechanism, in
lieu of employing a fixed eccentric, by which only a determined degree of expansion
is effected, as in the prior construction aforesaid, the eccentric 21, is adapted to be
moved transversely to the crank shaft 4, with which it rotates, so as to cut off
steam from the cylinders 1, 1, at earlier or later periods of the stroke of their
pistons 8, 8, by reduction or increase, respectively, of the travel of the valve 12,
in accordance with variations in the position of the eccentric, relatively to the line
of the cranks. To effect such variation, in manner and degree proper to maintain
a uniform determined speed of the engine, the eccentric 21, is fitted freely on the
crank shaft 4, by being provided with a slot 22, the dimensions of which are such
as to admit of the required degree of transverse movement, and is connected
directly to a centrifugal governor or regulator, fixed upon the crank shaft 4, and
located between the inner arms of the double cranks 10, 10, thereof. Such
connection is effected, preferably, by pivoting an arm 23, on the eccentric 21', to
a pin 24, fixed in a governor disc 25, which is formed upon or secured to one of
the inner crank arms 10, and carries a centrifugal governor of any 'suitable and
preferred construction.
In the construction of the governor, as herein applied, we suitably secure upon
the crank shaft 4, of the engine, as closely as may be to the eccentric 21, which
actuates the main or distribution valve, a disc 25, which serves as the support
of the several members of the governor. The disc 25, is, in this instance, connected
directly to one of the cranks 10, but may obviously occupy any other desired
position on the shaft. A pair of weights or pendulums 26, is pivoted, by pins 27,
to the disc 25, at points adjacent to its periphery, and at equal distances,
diametrically, from its centre, said weights having the capacity of vibration

page_text: about the axes of the pins 27, within a range limited outwardly by stops 31, fixed
on the disc 25, and inwardly by the crank shaft 4, or by stops adjacent thereto.
The action of gravity upon the weights 26, is eliminated, and their conjoined
outward movement, under the influence of centrifugal force, effected, by coupling
them together by a link 28, the ends of which are journalled on pins 32, fixed to
the weights, the coupling pin 32, of one weight being located between its pivot 27,
and its free end, and that of the other weight being secured in an extension thereof
beyond its pivot, and on the opposite side of the pivot centre to that on which the
main body of the weight is located.
The distance between centres of pivot pins and coupling pins is equal in both
weights, and it will therefore be seen that both outward and inward vibration of
the weights must be coincident and through equal arcs, and also that the action
of gravity, in tending to vibrate either one of the weights upon its pivot, will be
counteracted by an equal force acting in an opposite direction upon the other
weight, so that, in operation, outward movement of the weights will be induced
only by the centrifugal force resultant upon the speed of rotation of the crank
shaft.
Each of the weights is connected, by a helical spring 30, to a standard 35,
secured upon the disc 25, the resilience of said springs exerting a centripetal action
upon the weights, of such proper and determined degree as to maintain the
requisite equilibrium with their centrifugal force for desired rates of speed of the
engine. The pins 36, to which the springs are connected, are located upon
the weights, adjacent to their pivots 27, and, in order to diminish wear, and
obviate tendency to cramping or binding, the pins 36, are provided with circular or
segmental sleeves or bearings 37, around which the ends of the springs 30, are
hooked or bent, as shown in Fig. 1, the sleeves being preferably grooved or recessed
on their peripheries to receive the ends of the springs, as seen in Figs. 12 and 13.
Wearing surfaces of ample size are thus provided, and the centripetal action of the
springs is exerted upon the weights, in line with the axes of the pins 36, irrespective
of the position or angle of vibration of the weights.
The eccentric 21, which operates the main or distribution valve of the engine,
is formed in two sections which are connected by bolts, and is adapted to fit freely
on the crank shaft, with the capacity of movement transversely thereto, in
accordance with vibrations of the weights 26, about their pivots 27. To this end
an opening or shaft recess 22, is formed in its body, of diameter and length proper
to admit of the degree of transverse movement required, and one of its sections is
formed in one piece with or secured to an arm 23, the opposite end of which is
journalled on a pivot 24, secured to the disc 25. A link 29, is coupled, at one end,
to a pin 34, on one of the weights 26, and, at the other, to a pin 33, on the
eccentric, which through such connection, is, by movement of the weights in
either direction, moved transversely to the crank shaft, upon the pivot 24, as a
centre, its eccentricity, and consequently the length of traverse which it imparts to
the valve with which it is connected, being varied coincidently with the movements
of the weights, and proportionately to the range of said movements.
The Drawings illustrate the position of the parts when the engine is at rest, the
eccentric having its greatest degree of eccentricity and imparting the maximum
travel to the valve. The outward movement of the weights, under the influence
of centrifugal force sufficient to overcome the centripetal action of the springs,
moves the eccentric towards the left, correspondingly reducing its eccentricity, which
is least when the weights are moved to the limit of their outward range, and the
intermediate positions of the eccentric, as required to effect different degrees of
expansion, are determined by the preponderance of force exerted as between the
centrifugal action of the weights and the centripetal action of the springs under
variations of pressure and load or either.
It will be seen that the effect of the regulating mechanism is transmitted
directly to the eccentric, and that the construction and arrangement of the members
is such that they may be located within a comparatively small compass without

page_text: impairing the facilities for making such adjustment or renewal of parts as may
from time to time become necessary.
By combining, as above set forth, a centrifugal governor located between the
cranks of a double cylinder single acting engine, with a movable eccentric actuating
a distribution valve common to both cylinders, all rock shafts and intermediate
connections are dispensed with, the action of the governor is transmitted directly
to the eccentric, and thence to the valve, and the moving parts of the regulating
mechanism are ensured proper and continuous lubrication during operation, and
fully protected from the access of dust, grit, and other foreign matters.
It will be seen that by reason of the substantially vertical position of the main
valve 12, and its guide piston 17, the gravity of said members, added to that of
the eccentric, tends to resist the upward, and accelerate the downward movement.
of the valve, and to counteract such tendency and balance the weight of the parts,
the upper piston 38, of the valve, is made of larger diameter than the lower
piston 39, the sleeve or bushing 40, of the valve chamber, within which the valve
works, being bored out correspondingly. The difference of diameter between the
upper and lower pistons is such that the tendency to upward movement, induced
by the excess of steam pressure upon the upper piston, shall be equal, as nearly as
may be, to the downward tendency of the gravity of the valve and eccentric,
which being thus balanced, will be correspondingly more sensitive to the action of
the governor in varying the point of cut off.
The pistons 38, and 39, which constitute the bearing surfaces of the main valve 12,
are packed by split rings 41, of metal, which are sprung into circumferential
recesses in the pistons, and, as heretofore constructed, have been without provision
for ensuring a tight bearing longitudinally upon their seats in the pistons, as is
desirable in preventing leakage of steam past the pistons and preventing undue
friction. The requisite tightness of the packing rings is assured under our present
Invention, by forming circumferential grooves 42, in the pistons 38 and 30, on
the steam side of each packing ring 41, so as to expose a portion of one of the
sides of each ring to the pressure of the steam in the chamber, and placing the
opposite sides of the rings in communication with the exhaust passage through
the centre of the valve, such communication being effected by forming a channel 43,
on the exhaust side of each ring, above one or more openings 44, leading through
the metal of the piston, from the adjacent seat of the ring to the inside of the
piston, as shown in Figs. 5 and 7. The rings are thus held to their seats by the
pressure of the steam upon an area equal to that of the channels 43, and,
consequently, move with the valve as if made solid therewith, without tendency to
release or relief, by such movement, of their outward bearing upon the lining 40
of the valve chamber. The rings 41, should be fixed as against rotation upon their
pistons, to prevent steam blowing through their joints into the openings 44, by
dowel pins 45, or in any other suitable manner.
In the operation of steam engines, accidents, of more or less serious character,
are frequently occasioned through the neglect of the engineer to clear the cylinder
of water which has accumulated by the condensation of steam therein, and in the
steam and exhaust pipes, or which has been carried over with the steam by priming
or by reason of the water level in the boiler being unduly high. In addition to
the damage which the engine itself sustains, serious loss often results from the
stoppage of the machinery which it operates, and it is consequently desirable not
only to exercise all possible effort and precautions for the prevention of accidents
of the character referred to, but also to reduce, as far as may be, their injurious
effect where preventive measures have been neglected or proven insufficient. We
comply with the requirement last stated, by providing a member whose capacity of
resistance, while sufficient to sustain the maximum pressure which may be normally
and safely exerted in the cylinder, is so limited relatively to that of other members
subject to equal strain, as to ensure its fracture before the attainment of a sufficiently
high degree of pressure to effect damage to other parts, and which, when broken,
can be quickly and cheaply replaced,

page_text: To this end, we provide each cylinder head 64, with a relief plate 65, which is
driven or screwed into the body of the cylinder head against a shoulder therein,
by which it is prevented from being forced outwardly by internal pressure, and
form, in the plate 65, a groove or recess 66, the depth of which is such as to reduce
the strength of the relief plate to such degree as shall be proper to sustain a
determined pressure greater than the maximum working pressure under which the
engine is designed to operate and less than that which would be sufficient to cause
damage to other parts in the event of breakage. The relief plate will consequently
remain intact so long as the normal working pressure, or any safe addition thereto,
is not exceeded, but upon the exertion of internal pressure in excess of the limit of
resistance which it is constructed to afford, it will fracture through the groove 66,
and relieve such excess of pressure, without injurious effect other than causing a
brief stoppage of the engine for the insertion of a new plate.
The relief plate is connected by a bolt 67, engaging a thread in a central hub or
boss 68, on its outer side, to an outer plate 69, which rests on the top of the
flange 70, of the cylinder head. The flange and body of the head being located in
different planes a cylindrical space is formed within the head, on its outer side, for
which the outer plate serves as a cap or cover. The outer plate 69, serves to jacket
the head, as is desirable, as well as to present a neat external finish.
In order to provide for ready escape of water of condensation which may find
access to the cylinders 1, a relief port or channel 46, is formed in the body of
each cylinder, leading from the bore thereof to the exhaust passage 15, said ports
opening into the cylinders at such level as to be uncovered by the pistons 8, when
at the lower extremities of their stroke, and thereby to permit the discharge into
the exhaust passage, of any water of condensation that may be present in the
cylinder, before the next upward stroke of the piston. A drain pipe 47, provided
with a cock or valve 48, to prevent blowing through of exhaust steam, is led from
the exhaust passage 15, to the crank case 2, or to the lower portion of the valve
chamber 3, and serves, by discharging water of condensation from the exhaust.
into the crank case, to relieve the exhaust pipe therefrom, as well as to assist in
maintaining the proper level of the lubricating mixture of oil and water in the
crank case.
A discharge pipe 49, may be connected to the pipe 47, above the
valve 48, to carry off any surplus of water above that which may be needed to
maintain a desired level in the crank case.
The journals 50, of the crank shaft 4, which are preferably tapered from their
inner to their outer ends as seen in Fig. 1, rotate in cylindrical bearings 5,
provided with Babbitt metal linings 52, and secured in sockets or supports 53,
projecting outwardly from the ends of the crank case 2. Chambers 54, for the
reception of lubricating material, are formed at the outer ends of the journals 50,
by caps 55, fitting freely over the crank shaft 4, and secured to the end flanges of
the bearings 51, and passages 56, extend from the bottoms of the chambers 54, to
the crank case. Rings or wipers 57, secured to the crank shaft, and rotating
therewith, within the chambers 54, serve to intercept the oil which passes along
the shaft from the outer ends of the journals 50, and effect its projection into the
chambers 54, from which it is returned, through the passages 56, to the crank case.
To enable a continuous feed of oil to the crank case to be maintained during
operation, an oil reservoir 58, having an upper supply opening 59, is fixed the
lower cylinder flanges, in the space between the cylinders, so as to be enclosed
entirely by the cylinders, valve chamber and cylinder casing, and is provided with
oil feed pipes 60, having regulating cocks 61, which discharge into the oil cups 62,
of the crank shaft bearings. The capacity of the oil reservoir is such as to enable
it to receive, at a single charge, a supply of lubricant sufficient for a considerable
period of operation of the engine, and, by proper adjustment of the cocks 61, a
slow and continuous feed is afforded, without attention on the part of the operator.
Lubrication of all the moving parts, except the pistons and valves, is thus effected
from a single point, and the excess of oil, if any supplied to the crank shaft
journals being returned to the case by the wipers on the crank shaft, waste of oil

page_text: is effectually prevented, and cleanliness of the engine and its surroundings
correspondingly promoted.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is:
1. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, each located above and having its piston connected to the crank pin of
a double crank upon a common crank shaft, a main or distribution valve working
in a valve chamber between said cylinders and governing the supply and exhaust
thereof, and a centrifugal governor fixed upon the crank shaft between its cranks,
and coupled directly to an eccentric which reciprocates the main valve and is
movable transversely relatively to the crank line.
2. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, each located above and having its piston connected to the crank pin
of a double crank upon a common crank shaft, a differential piston main or
distribution valve, operated by an eccentric on said shaft and governing the supply
and exhaust of the cylinders, said valve having an upper piston of greater area
than its lower piston, and a valve chamber having a supply pipe which admits
steam between said pistons, these members being combined for joint operation to
effect the balancing of the weight of the valve and eccentric by the excess of
pressure on the larger valve piston.
3. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, each having a port for the admission and exhaust of steam at or near
its upper end, pistons fitting said cylinders and connected to cranks on a common
crank shaft, and a water relief passage leading from each of said cylinders to the
exhaust pipe, said passages having their openings to the bore of the cylinders
located at such level therein as to be uncovered by the pistons when at the lowest
extremity of their strokes.
4. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, located above a closed crank case and having their pistons coupled to
cranks on a shaft rotating therein, a main or distribution valve governing the
supply and exhaust of said cylinders, and a drain pipe leading from the exhaust
passage of the main valve chamber to the crank case, and provided with a
regulating cock or valve.
5. The combination, substantially as set forth, of a main or distribution valve
composed of two hollow pistons connected by a tubular body, and packing rings
sprung into peripheral recesses in the pistons, each of said rings having a groove
one side fitting against a seat which communicates by a passage with the
interior or exhaust side of the valve, and being exposed, on its opposite side, by
a circular recess cut in the valve, to the pressure on the steam side thereof.
on
6. The combination, substantially as set forth, of a hollow piston valve having
circumferential packing recesses, which are grooved or relieved on one side and
communicate, on the other side, by a passage or passages, with the interior of the
valve, and packing rings which fit in the packing recesses and are provided with
grooves communicating with the passages therein.
7. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, located above a closed crank case and having their pistons coupled to
cranks on a shaft rotating therein, chambers enclosing said shaft at the outer ends
of the bearings thereof, rings or wipers secured upon the shaft within said
chambers and passages connecting said chambers with the crank case.
8. The combination, substantially as set forth, of a pair of vertical single acting
cylinders, located above a closed crank case and having their pistons coupled to
cranks on a shaft therein, a main valve working in a valve chamber located
between said cylinders and actuated by an eccentric on said shaft, an oil reservoir
fitting in the space between the cylinders and valve chamber, and oil supply pipes
leading from said oil reservoir to the oil cups of the crankshaft-bearings.

page_text: 9. The combination, substantially as set forth, of a disc adapted to be fixed
upon the main or crank shaft of an engine, a pair of weights pivoted to said disc
on opposite sides of its centre, a coupling link connecting said weights at points
within and without the centres of their pivots respectively, a pair of springs, each
connected at one end to the disc and at the other to one of the weights, an eccentric
which is slotted to surround the crank shaft, with the capacity of movement
transversely thereto, an arm secured at one end to said eccentric and pivoted at
the other to the disc, and a link connecting the eccentric with one of the weights.
10. The combination, substantially as set forth, of a disc adapted to be fixed
upon the main or crank shaft of an engine, a weight pivoted to said disc and
coupled by a link with an eccentric fitting freely on the shaft and a spring
connected at one end to the disc and having its opposite end bent or hooked around
a segmental sleeve or bearing on the weight.
11. The combination, substantially as set forth, of a cylinder head and a relief
plate, the strength of which is less than that of the head.
12. The combination, substantially as set forth, of a cylinder head and a relief
plate having its transverse section reduced by a groove or recess.
13. The combination, substantially as set forth, of a cylinder head, a grooved or
recessed relief plate secured against a shoulder therein and having an outwardly
projecting hub or boss, an outer plate bearing on the flange of the head, and a
bolt connecting said outer plate with the hub of the relief plate.
Dated this Twenty-seventh day of March 1884