Year: 1885

page_text: I, THOMAS MUDD, of West Hartlepool, in the County of Durham, Engineer, do
hereby declare the nature of this invention to be as follows:-
In large engines in which it is necessary to divide the framework into separate
castings, I make the division by means of a horizontal joint through or near the
centre of the condenser so that part of the condenser is in the lower casting and
part in the upper casting, instead of by the usual vertical joint.
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When the engines have three cranks I support the crank shaft on four main
bearings, and when they have two cranks I support it on three main bearings.
I actuate the valves by a special form of valve gear of the type now well known
by the name 'dynamic," and I make the crank shaft in sections which are exact
duplicates of each other, and which are formed in such a manner as to suit the
valve gear, and the main bearings in the lower casting of the framework whilst
keeping every crank supported by main bearings close to each side of its cheeks.
The cranks are formed by the combination in the same crank of one cheek that
is recessed for a coupling flange, and one cheek that has an eccentric forged or cast
solid with it.
In the valve gear I employ a single straight slide in the place of the double slide
or radius link of other dynamic gears, thus enabling the eccentric to be close to
and part of the crank cheek, and at the same time secure extreme simplicity and
fewness of parts. I prefer to place the slide between the crank shaft and the
condenser, so that the valves may be at the back of the engines, and the valve gear
still have its minimum number of parts..
I prefer to use a single straight slide of T or other similar shape in cross section
with a slide block of corresponding shape to receive the slide. The slide block is
supported on a rocking shaft about whose axis a movement is permitted, and to the
side of the slide block a pin is fitted for attachment of the drag rod for reversing.
The slide carries a pin to which the eccentric rod is attached. In situations

page_text: where there is sufficient room the upper and lower limbs of the slide block may be
.connected together, either at the end or ends, or at the side towards the pin for
the purpose of giving additional strength.
On the eccentric rod of the dynamic valve gear, I forge or fix a tail guide on
that part that is on the opposite side of the crank shaft to the slide; the object of
the tail guide being to cause the eccentric rod always to work in one plane, and
not follow the crank shaft in its movements fore and aft due to wear or slackness
in the thrust block; and to further carry out this object I make the eccentrics on
the crank cheeks quite parallel and without any shoulder or projecting part round
their periphery so that they may easily move through the eccentric strap when the
crank shaft moves in a fore and aft direction without in any way disturbing or
straining the valve gear.
To change the degree of expansion, and to reverse the engines I rotate the slide
block around the axis of the pin or shaft on which it is supported by causing the
pin to which the drag rod is attached to describe a portion of a circle, the hand or
steam or other reversing gear being attached to this pin by any well known
mechanism. When I use steam reversing gear I prefer to adopt one or more
(generally two) cylinders of the oscillating type in which I employ fixed valve
cheeks in one piece with or secured to the framing of the reversing engine, which
valve chests contain any usual type of steam valve actuated by ordinary methods
precisely as if the cylinders were not oscillating. To enable the cylinders to
oscillate I make them with a trunnion or journal on each side, the end of one
trunnion being forced so as to form a steam tight joint when bearing against a
similar face on the fixed valve chest, the necessary pressure between the faces being
provided by causing pressure to be applied against the opposite trunnion by means
of a spring adjustable by screws or in large engines by a steam or other cylinder
and piston, or an equivalent of these. The trunnion that is faced is pierced by
two steam ports, communicating with the two ends of the cylinder respectively,
the ports being of such a size and shape as to be always in open communication
with the corresponding steam ports in the fixed valve chest.
In triple expansion, double expansion and other compound engines I place one
cylinder immediately upon or at the end of another in the same axis, in such
manner that there will be no gland between them, and no part of the piston rod
between the cylinders is exposed to the atmosphere; the rod passing through a
simple bush, or bush with spring packing rings between the cylinders. I enclose
the valve rod between the two valve chests, or one valve chest common to both
valves in a similar manner and thus avoid the friction and other defects inherent
in the use of numerous packed glands. I arrange this by making the valve of the
upper cylinder a hollow piston valve worked by a rod outside of the periphery of
the valve and the steam entering and passing through the interior of the valve,
so that the rod may be wholly in the exhaust space from the valve of the high
pressure cylinder and not in the high pressure space at all.
It can by this means be carried down to the slide valve of the lower cylinder
without any gland at all, and entirely enclosed from the atmosphere as the pressure
is the same at all parts of the space it passes through, until it reaches the gland at
the bottom of the lower valve chest. By these means, I utilize the steam in the
upper cylinder without allowing it at any point to come in contact with a gland
until after it has exhausted from that cylinder, and become consequently reduced
in pressure and temperature.
To enable the top cylinder to be very readily lifted to permit of examination of
the lower cylinder, I take a branch steam pipe from the steam space at the lower
end of the upper valve, and bend it down in such a way that the face of the branch
may be faced off at the same time as the cylinder face, so that it may joint down
steam tight onto a recess in the lower cylinder, which communicates with the
source of steam, or onto a steam pipe direct. The hollow piston valve fits into

page_text: this branch, when steam is cut off from the lower part of the upper cylinder, the
steam then passing through the hollow piston valve to the upper port.
In order to enable one easily to get at and examine the lower cylinder and piston
when the axis is vertical which is the position I prefer, I provide 3 long lifting
screws with nuts having ratchet brace attachments for turning them. These are
preferably shipped into recesses in the upper part of the lower cylinder and stand
up vertically beside the upper cylinder passing through gaps in strong snugs on the
upper cylinder, which snugs are preferably placed at about the horizontal level of
the centre of gravity of the upper cylinder. The screws themselves are each fitted*
with a ratchet working on a nut. When the screws are shipped the ratchets are
worked so as to bring the nuts up against the snugs, and the snugs can be knifed
out on their under sides to let the nut enter slightly into them, as the recess so
formed will prevent the screws from having any chance of getting out of the gaps
in the snugs. As soon as the nuts have begun to bear against the snugs it is clear.
that by continuing to turn the three ratchets evenly and thus raising the nuts
uniformly, the cylinder must be forced up in a line perfectly fair with the axis of
the piston rod; and thus by putting the engine on the top centre the top cylinder
may be raised straight up a distance equal to the stroke of the engine before the
top piston will foul the bottom of its cylinder. Less than this will generally be
enough to allow of perfectly free examination of the piston of the lower cylinder.
These lifting screws should be marked in figures which can be read off from a
pointer on the top of the snug or elsewhere, so that the lifting may with the least
possible trouble be kept substantially equal on all sides.
When I use steam reversing gear either of the oscillating or fixed cylinder type,
I prefer to fix the reversing engine at the back of the main engines in such a way
as to work direct on the reversing shaft, the latter pressing through to the front
where the large hand wheel for reversing by hand power is attached to it. The
reversing shaft is a tube with a flange coupling at the back end, where it is
attached to the crank shaft of the reversing engine. Through the tube I pass a
small shaft so that at the front end it is concentric with the tube, and at the back it
is eccentric with the tube, being retained in these relations by plugs in the ends of
the tube, with holes through the plugs at the proper places, so that the small shaft
may rotate in the said holes. On the front end of the small shaft a small hand*
wheel or its equivalent is fixed, and at the other end between the flanges of the
coupling that connects the tube to the crank shaft of the reversing engine the
small shaft has an eccentric for the purpose of driving the valve or valves of the
reversing engine. The amount of eccentricity of the eccentric on the small shaft
is the same or nearly the same as the amount of eccentricity of the back end of
the small shaft in the tube, so that when the small hand wheel (which has a stopper
to prevent it turning more than an arc of a circle) is in its mid position the
eccentric on the small shaft is quite or nearly central with the tube, and therefore
with the crank shaft; so that if the engine were turned with the small hand wheel
in that position the valves would have little or no motion, and the engines would
therefore, not continue to run; but by turning the small hand wheel in one direction
or the other from its mid position, sufficient throw is given to the eccentric
(measured from the centre of the reversing shaft) to cause the valves to have
motion enough to keep the engine running; and the direction in which it will run
is determined by the direction in which the small hand wheel is turned. I transmit
the motion of the eccentric to the valves first by means of a concentric ring or
sheave which is quite loose upon the eccentric, but which is caused to revolve
thereon by the bolts or snugs in the flange couplings of the shaft coming in
contact with one or more of its arms. Around this concentric ring is an ordinary
eccentric strap and rod through which the 'motion is taken in the usual manner to
the valve spindle or spindles. I prefer to place on the reversing shaft or tube a
worm, which gears into a quadrant or worm wheel, preferably the latter forming
what is known as an "all round" gear.

page_text: When I place the reversing engine in front of the main engines I do not require
the reversing shaft to be a tube, neither do I require the long small shaft, nor the
concentric ring on the eccentric. I simply place a stud in the end of the crank
shaft, which stud carries the eccentric loosely, enabling it to be turned by hand by
means of a handle or hand wheel; but this arrangement is not so suitable for
. enabling the large hand wheel to be conveniently placed.
I THOMAS MUDD, of West Hartlepool 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:
In large engines in which it is necessary to divide the framework into separate
castings, I make the division by means of a horizontal joint a through or near the
centre of the condenser A so that part of the condenser is in the lower casting A¹
and part in the upper casting A¹ instead of by the usual vertical joint (see
Figure 1).
When the engines have three cranks I support the crank shaft on four main
bearings, and when, they have two cranks I support it on three main bearings.
I actuate the valves by a special form of valve gear of the type now well known
by the name 'dynamic," and I make the crank shaft in sections B, B1, B11
(Figure 2) which are exact duplicates of each other and one short piece of simple
form at the forward end, all of which are formed in such a manner as to suit the
valve gear, and the main bearings in the lower casting A¹ of the framework, whilst
keeping every crank supported by main bearings close to each side of its
cheeks b b¹.
The cranks are formed by the combination in the same crank of one cheek b
that is recessed at 6' for a coupling flange 63 and one cheek 61 that has an
eccentric C forged or cast solid with it..
In the valve gear which is shown in Figures 3 and 4, (being plan and elevation)
I employ a single straight slide D in the place of the double slide or radius link of
other dynamic gears, thus enabling the eccentric to be close to and part of the

page_text: crank cheek, and at the same time secure extreme simplicity and fewness of parts.
I prefer to place the slide between the crank shaft and the condenser so that
the valves may be at the back of the engines, and the valve gear still have its
minimum number of parts.
I prefer to use a single straight slide D of T or other similar shape in cross
section, with a slide block D¹ of corresponding shape to receive the slide. The
slide block D may be attached to or made in one piece with a rocking shaft D'
which works in bearings d, and about whose axis a movement is permitted, and
to the side of the slide block a pin E is fitted for attachment to the drag rod for
reversing.
The slide D carries a pin d to which the eccentric rod is attached. In situations
where there is sufficient room the upper and lower limbs d³ ³ of the slide block
may be connected together, either at the end or ends, or at the side towards the
pin E for the purpose of giving additional strength, Figure 5 is a sectional and
Figure 6 a front elevation of a modified form of slide block. In this instead of
fixing the block D¹ to a rocking shaft D* the block itself is made to oscillate in a
circular recess D³ in the bed plate or other suitable bearing of circular contour.
This bearing D³ may be made of any suitable cross section.
On that part of the eccentric rod C¹ of the dynamic valve gear that is on the
opposite side of the crank shaft to the slide, I forge or fix a tail c working between
guide plates c¹ as shown in Figure 7. The object of the tail guide is to cause the
eccentric rod always to work in one plane, and not follow the crank shaft in its
movement fore and aft, due to wear, or slackness in the thrust block; and to
further carry out this object I make the eccentrics on the crank cheeks quite
parallel and without any shoulder or projecting part round their periphery as
shown in Figure 2, so that they may easily move through the eccentric strap o¹
when the crank shaft moves in a fore and aft direction without in any way
disturbing or straining the valve gear.
To change the degree of expansion and to reverse the engines I rotate the slide
block D¹ around the axis of the shaft D' or other bearing in which it is supported
by causing the pin E to which the drag rod is attached to describe a portion of a
circle, the hand or steam or other reversing gear being attached to this pin by any
well known mechanism. Referring now to Figure 8. When I use steam reversing
gear I prefer to adopt one or more (generally two) cylinders G of the oscillating
type in which I employ fixed valve chests F in one piece with or secured to the
framing of the reversing engine which valve chests contain any usual type of
steam valve such as the slide valve f as shown which is actuated by ordinary
methods precisely as if the cylinders were not oscillating. To enable the cylinders
to oscillate I make them with a trunnion or journal on each side, the end of one
trunnion g being faced so as to form a steam tight joint when bearing against a
similar face f¹ on the fixed valve chest F, the necessary pressure between the faces
being provided by causing pressure to be applied against the opposite trunnion g¹
by means of a spring g' adjustable by a screw g³ or in large engines by a steam or
other cylinder and piston or an equivalent of these. The trunnion g that is faced
is pierced by two steam ports f f communicating with the two ends of the
cylinder G respectively being of such a size and shape as to be always in open
communication with the corresponding steam ports in the fixed valve chest.
In triple expansion, double expansion and other compound engines, and especially
when altering compound engines into triple expansion by the addition of a cylinder,
I sometimes place as shown in Figure 9 one cylinder H immediately upon or at
the end of another H' in the same axis, in such manner that there will be no
gland between them, and no part of the piston rod h between the cylinders exposed
to the atmosphere; the rod passing through a simple bush h¹ or bush with spring
packing rings between the cylinders, not shown in the drawings. Referring to
Figure 10, I enclose the valve rod I between the two valve chests, J and J¹ or one
valve chest cominon to both valves (as shown in drawings) in a similar 'manner

page_text: .
and thus avoid the friction and other defects inherent in the use of numerous
packed glands. I arrange this by making the valve K of the upper cylinder Ha
piston valve preferably hollow worked by a rod I outside of the periphery of the
valve K the steam entering and passing through the interior of the valve, so that
the rod may be wholly in the exhaust space J J¹ from the valve of the high
pressure cylinder and not in the high pressure space at all. The rod I can by this
means be carried down to the valve L of the lower cylinder without any gland at
all and entirely enclosed from the atmosphere (the pressure being the same at all
parts of the space it passes through), until it reaches the gland at the bottom of the
lower valve chest, not shown in drawings. By these means, I utilize the steam in
the upper cylinder H without allowing it at any point to come in contact with a
gland until after it has exhausted from that cylinder, and become consequently
reduced in pressure and temperature. To enable the top cylinder H to be lifted to
permit of examination of the lower cylinder H¹ and piston h¹ without breaking
more than the one main joint I take a branch M for the steam from the steam
space m at the lower end of the upper valve K, and bend it down in such a way
that the face m² of the branch may be faced off at the same time as the cylinder
face, so that it may joint down steam tight on to a recess in the lower cylinder,
which communicates with the source of steam, or onto a steam pipe or throttle
valve direct.
In order to enable one easily to get at and examine the lower cylinder H¹
and piston h¹ when the axis is vertical which is the position I prefer, I provide
three long lifting screws N with nuts N¹ having ratchet brace attachments n for
turning them, such as are shown in Figures 11 and 12 (being elevation and plan).
These are preferably shipped into recesses h" in the upper part of the lower
cylinder Hand stand up vertically beside the upper cylinder H passing through
gaps h³ in strong snugs h* on the upper cylinder, which snugs are preferably placed
at about the borizontal level of the centre of gravity of the upper cylinder. The
screws themselves are each fitted with a ratchet n working on a nut. When the
screws are shipped the ratchets are worked so as to bring the nuts N¹ up against
the snugs h, and the snugs can be knifed out on their under sides as shown at n¹,
to let the nut enter slightly into them, as the recess so formed will prevent the
screws from having any chance of getting out of the gaps in the snugs.
as the nuts have begun to bear against the snugs it is clear that by continuing to
turn the three ratchets evenly and thus raising the nuts uniformly, the cylinder
must be forced up in a line perfectly fair with the axis of the piston rod; and thus
by putting the engine on the top centre the top cylinder may be raised straight up
a distance equal to the stroke of the engine before the top piston will foul the
bottom of its cylinder. Less than this will generally be enough to allow of
perfectly free examination of the piston h¹ of the lower cylinder. These lifting
screws should be marked in figures which can be read off from a pointer on the top
of the snug or elsewhere, so that the lifting may with the least possible trouble be
kept substantially equal on all sides.
As soon
When I use steam reversing gear either of the oscillating or fixed cylinder type,
I prefer to fix the reversing engine at the back of the main engines in such a way
as to work direct on the reversing shaft, and arrange the shaft and control, the
reversing engine by a device such as shown in section in Figure 13. The reversing
shaft O passes through to the front of the engine where the large hand wheel 01
for reversing by hand power is attached to it. The reversing shaft is a tube with
a flange coupling O' at the back end, where it is attached to the crank shaft Q of
the reversing engine. Through the tube OI pass a small shaft P so that at the
front end it is concentric with the tube, and at the back it is eccentric with the
tube, being retained in these relations by plugs 03, 0³, in the ends of the tube, with
holes of o through the plugs at the proper places, so that the small shaft may
rotate in the said holes. On the front end of the small shaft P, a small hand
wheel 2 or its equivalent is fixed, and at the other end, between the projecting

page_text: flanges 0 of the coupling that connects the tube to the crank shaft of the
reversing engine, the small shaft P has an eccentric P' for the purpose of driving
the valve or valves of the reversing engine. The amount of eccentricity of the
eccentric P¹ on the small shaft is the same or nearly the same as the amount of
eccentricity of the back end of the small shaft P in the tube, so that when the
small hand wheel (which has a stopper not shown on the drawings to prevent it
turning more than an arc of a circle) is in its mid position the eccentric P¹ on the
small shaft is quite or nearly central with the tube O and therefore with the crank
shaft Q; so that if the engine were turned with the small hand wheel in that
position the valves would have little or no motion, and the engines would therefore
not continue to run; but by turning the small hand wheel p in one direction. or
the other from its mid position, sufficient throw is given to the eccentric (measured ·
from the centre of the reversing shafts O) to cause the valve to have motion
enough to keep the engine running; and the direction in which it will run is
determined by the direction in which the small hand wheel p is turned. I transmit
the motion of the eccentric to the valves first by means of a concentric ring or
sheave P which is quite loose upon the eccentric, but which is caused to revolve
thereon by the boltscor snugs 0% in the flanged coupling of the shaft O coming in
contact with one or more of its arms P³ around the concentric ring P' is an ordinary
eccentric strap P' with rod P' attached through which the motion is taken in the
usual manner to the valve spindle or spindles P. I prefer to place on the reversing
shaft or tube O a worm 0, which gears into a quadrant or worm wheel 0³
preferably the latter forming what is known as an "all round" gear.
When I place the reversing engine in front of the main engines I do not require
the reversing shaft to be a tube, neither do I require the long small shaft, nor the
concentric ring on the eccentric instead of these I simply place as shown in
Figure 14 a stud Q¹ in the end of the crank shaft, Q, which stud carries the
eccentric P¹ loosely, enabling it to be turned by hand by means of a handle or hand
wheel p, but this arrangement is not so suitable for enabling the large hand wheel 0¹
to be conveniently placed.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. In marine or other condensing engines the division of the main framework
castings by a horizontal joint at or near the middle of the height of the condenser,
substantially as herein set forth.
2. In a crank shaft either solid or built the combination of one cheek that is
recessed for a flange coupling, and a second cheek that has an eccentric forged or
cast solid with it, substantially as herein described.
3. In "dynamic" valve gear the combination of a single straight slide of any
suitable cross section, provided with a pin d for attachment to eccentric rod, the
slide being free to reciprocite in the same plane as that in which the block moves,
substantially as and for the purpose set forth.
4. In combination with the eccentric rod of "dynamic" valve gear, the tail c
and guide c¹ in which it works, for the purpose of preventing lateral motion in the
eccentric rod, substantially as set forth in Figure 7.
5. In an oscillating engine, the combination of a valve chest F fixed and
independent of the motion of the cylinder, with a movable trunnion g pierced' by
suitable steam ports f' and kept steam tight by the faced joints f¹on one trunnion g
and adjusting device g³ 9' on the other trunnion g¹, substantially as shown in
Figure 8.
6. In a steam engine working expansively, the combination of a high pressure
piston valve and a low pressure slide or piston valve on one and the same rod and
in the same steam chest whereby the high pressure steam is prevented from coming
in contact with the valve rod and its glands, substantially as shown in Figure 10.

page_text: 7. In a steam engine, the cylinders of which are arranged one immediately over
the other on the same axis as herein set forth, the combination of a snug h* having
in it a gap h³ on the upper cylinder, a socket h³ in the lower one, and a screw and
ratchet device N, substantially as and for the purpose set forth in Figures 11
and 12.
8. In a steam engine the method of and apparatus for working the reversing
engine from the front of the main engine by means of a hand wheel p and
eccentric P¹ which is attached to the end of a shaft P lying eccentrically to the
hollow reversing shaft (through which it passes) and works the valve rod indirectly
by means of the sheave P2, substantially as set forth in Figures 13 and 14:
9. In a steam engine the method of and apparatus for working the valves by
hand, substantially as described with reference to Figure 13.