IMPROVE- MENTS IN LOCOMOTIVE AND PORTABLE STEAM ENGINES
Year: 1871

page_text: LETTERS PATENT to Loftus Perkins, of Seaford Street, Gray's Inn
Road, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN LOCOMOTIVE AND PORTABLE STEAM ENGINES."
Sealed the 5th January 1872, and dated the 12th July 1871.
PROVISIONAL SPECIFICATION left by the said Loftus Perkins at the
Office of the Commissioners of Patents, with his Petition, on the
12th July 1871.
"
I, LOFTUS PERKINS, of Seaford Street, Gray's Inn Road, in the
County of Middlesex, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN LOCOMOTIVE AND PORTABLE STEAM ENGINES," to be
as follows:
This Invention has for its object "improvements in locomotive and
portable steam engines.
According to this Invention the boiler is constructed of layers of
wrought-iron tubes placed horizontally, each tube having solid ends
welded in. Each layer of tubes is connected to that above and below
by short vertical pipes. The vertical pipes are screwed at each end, one

page_text: with a right and the other with a left hand thread; this allows of the
vertical pipes being screwed simultaneously into two layers of horizontal
tubes. After the vertical pipes have been screwed in as tightly as
possible they are secured in their places by caulking.
.
Another mode is to screw or weld short nipples on to the horizontal
tubes, the protruding ends of the nipples having threads of different
pitch cut upon them ;, these nipples if screwed into the horizontal tubes
are secured in their places by caulking. The connection between the
nipples is then made by a socket, one end having a fine and the other a
coarse thread to suit that on the nipples. The socket is first screwed
on to the nipple with the fine thread as far as it will go, then a double
cone wrought iron or steel distance piece or copper washer with flat
ends is put in, this washer or double cone being of such a length that
it does not quite reach to the surface of the socket, the socket is then
screwed off the fine on to the coarse thread until the nipples are drawn
tightly together, the cone distance piece cutting into the flat ends of
the nipples or the copper washer flattening and so making a joint. The
fire-box is formed of wrought-iron tubes bent into the desired form to
make the sides of the box and connected to each other and the hori-
zontal layers above by short vertical pipes. If more than two vertical
pipes are used to connect to horizontal ones they must be screwed with
similar threads at both ends, one end having its screwed portion at least
twice that of the other. In putting together all the long ends are first
screwed into the horizontal pipes as far as they will go. The other tube
is then put into position. The vertical pipes are then screwed back
again as far as the short thread will permit them; they are then secured
by caulking. At the top of the boiler a pipe connected by similar
joints extends across and connects with each section to collect the steam
and pass it to the engine. The tubes forming the boiler are surrounded
by a double case of wrought iron, the space between the cases being
filled with vegetable black or other suitable non-conducting material.
The engine is of the type known as compound, and consists of a high-
pressure single-acting and a low-pressure double-acting cylinder with a
chamber of suitable proportion at the side. The piston for the high and
low pressure cylinder is made in one piece, the high-pressure piston
being so constructed as to fill the cylinder when at the top of the stroke.
The steam is passed to and from the high-pressure cylinder by a piston
valve and to the low by an ordinary slide valve. After being used in

page_text: the high-pressure: cylinder it is passed to the chamber and from the
chamber to the top and bottom of the low-pressure cylinder, the high-
pressure piston and the top annulus of the low making the down stroke
and the low pressure alone making the up stroke. The valves are
worked by eccentrics on the crank shaft and controlled by a link
motion in the usual manner. An important point in this arrangement of
cylinders is that the high-pressure steam never comes in contact with
the vegetable packing. The joints between the cylinder covers and
flanges are made by recessing copper washers and compressing them to
a perfect surface by bolts and nuts, and in some places very narrow
projecting surfaces are employed, the surface being sufficiently narrow
and the bolts strong enough to compress it to a joint. After the
steam has been used in the engine it is passed to the condensers
placed on each side of the boiler above the driving wheels. These con-
densers are composed of a series of small metal tubes placed in rows,
the ends of the tubes passing through plates into shallow chambers,
where they are securely fastened and made steam-tight. The steam
enters the chamber at the top, and the water formed by condensation
on the inner surface of the tubes flows out at the bottom into the
lower chamber, and from thence into the hot well where it is collected.
Pipes are fixed at the ends of the condensers to clear them of water
when ascending or descending an incline. The feed pump is peculiar
in construction, having only one valve and that on the delivery side.
The plunger is made to fit accurately the barrel of the pump. At the
top end of the barrel a port or opening is made leading to the hot well
during the outstroke; until the plunger reaches the edge of the port
it is making a vacuum. The moment the plunger passes the port the
water rushes in, and when the plunger returns and closes the port the
water contained in the barrel is forced through the delivery valve into
the boiler. The omission of the suction valve is of great importance
in pumping distilled and greasy water, owing to the liability of the
suction valve to adhere to its seat, and the consequent refusal of the
pump to work, or the suction valve may be mechanically lifted from
its seat. The engine is fitted with a direct acting steam pump, which
is composed of two steam cylinders and one water cylinder. The steam
cylinders are immediately above the pump. The top steam cylinder
is made just large enough to drive the water out of the pump and
overcome the friction, the lower steam cylinder large enough to lift
the plunger column of water overcome the friction, and work against

page_text: the constant pressure of the top cylinder, that cylinder being always
in communication with the boiler while at work. The distribution of
the steam from one piston to the other is effected by a piston valve
situated in the centre of the large piston and composed of four discs
on one spindle, the two outer ones fitting the cylinder loosely and the
inner ones fitting steam-tight. While making the down stroke the
valve is in a position that allows of the steam acting only on the small
piston, and at the same time the steam from the large cylinder passes
between the two centre discs into the exhaust pipe. When the piston
has nearly completed its down stroke one end of the piston valve runs
over a port in the side of the cylinder that connects that end with the
exhaust and allows whatever steam that has leaked past the outer loose
disc to escape, and at the same moment the steam that had leaked
past the disc at the other end expands and drives the valve over to the
other side; this opens the port connecting the large cylinder with
the boiler and closes the exhaust, the small cylinder now merely acts
as a pipe to the large as it makes the upstroke. When the piston has
nearly completed the upstroke the piston valve runs over a port at.
the top end of the cylinder on the opposite side to that just mentioned,
and in a similar manner drives the valve back again. A three-way
cock is placed on the suction pipe in such a position that it is capable
of regulating the supply of water to both pumps, from either the hot
well or supply tanks as required or shut them off entirely. The engine,
boiler, condensers, tanks, and coal bunkers are carried upon a strong
wrought-iron frame made of angle iron, the front of the boiler is
strutted to the frame to stiffen it at that point. The steamer is carried
on three wheels, two large for driving and one small for guiding, all of
which have india-rubber tyres. The india-rubber is protected from injury
by a flexible chain band extending entirely across the face of the tyre,
each link of which is connected to its neighbour by pins placed in such a
position that no undue strain can come upon them and at the same time
gives them the largest possible amount of wearing surface and flexibility,
The axle bearings of the front steering wheel have two laminated steel
springs one upon each side, the ends of the springs are connected to jaws
upon a large wheel plate, the outer extremity of which plate has a spur
wheel attached, a pinion driven by a vertical shaft gears into it, and
motion is imparted to this shaft by a worm and wheel. The wheel plate
is kept in its place by an internal flange embracing an angle iron ring
fastened to the main frame. The flue from the boiler is so arranged

page_text: that all the heated gases on their way to the chimney have to pass the
cylinders, this prevents any condensation taking place in them when
working the steam expansively and supplies the place of a steam jacket.
The safety valve consists of a conical valve, pressed by a spring on the
back, and covered by a casing having two escape pipes that lead the
steam when blowing off into the condensers; the valve is placed upon
the end of a siphon pipe filled with water to keep the valve cool and
indicate when it blows off by becoming hot to the touch. The water
gauge is made with the usual glass tube, but in place of taps screw-cocks
are used having long stuffing boxes to keep the packing cool, and the
glass is protected from breaking by two strong metal bars one upon
cach side connecting the ends and preventing them from bending
outwards when under great pressure. The boiler is provided with two
blow-off cocks, one for clearing it of water, and the other for relieving
the boiler from undue pressure. This cock is connected with the con-
densers by the escape pipe from the safety valve; both cocks are provided
with stuffing boxes placed at a distance from the steam to protect the
packing from the heat. Each condenser is provided with an air valve
loaded to a slight pressure to relieve the condensers from air and also
to act as a safety valve should they accidentally become charged with
steam to a greater amount than they are capable of bearing. The steam
pipe connections are made with sockets, the pipes being screwed with
right and left hand threads, one pipe having a flat and the other a
conical end. The flange joints are made with narrow surfaces or copper
washers and pulled up with bolts and 'nuts.
The arrangements above described are equally suitable for portable
and fixed engines, and peculiarly adapted to agricultural and locomotive
engines for use where fuel and water are scarce.

page_text: longitudinal vertical section, at Figure 1* a plan view partly in section,
and at Figure 1** a transverse section of a traction or locomotive engine
constructed in this manner.
At Figures 2 and 2* I have shewn similar views to Figures 1 & 1* of
a portable engine.
In these Figures are also shewn my improvements in the con-
struction of the boiler and other parts of a locomotive or portable steam
engine.
In these Figures A is the boiler; B, the compound engine; and C,
the condenser.
.
The boiler I construct of layers of horizontal wrought-iron tubes a, a,
each tube having solid ends welded in; each layer of tubes is connected
to that above and below by short vertical pipes b, b. The vertical pipes
are screwed at each end one with a right and the other with a left hand
thread. This allows of the vertical pipes being screwed simultaneously
into two layers of horizontal tubes. After the vertical pipes have been
screwed in as tightly as possible they are secured in their places by
caulking.
Another mode is to screw or weld short nipples on to the horizontal
tubes as at c, c, the protruding ends of the nipples having threads of
different pitch cut upon them. These nipples if screwed into the
horizontal tubes are secured in their places by caulking. The connection
between the nipples is then made by a socket, one end having a finc and
the other a coarse thread to suit that on the nipples. The socket is first
screwed on to the nipple with the fine thread as far as it will go; then
a double cone wrought-iron or steel distance piece or copper washer
with flat ends is put in, this washer or double cone being of such a
length that it does not quite reach to the surface of the socket. The
socket is then screwed off the fine on to the coarse thread until the
nipples are drawn tightly together, the cone distance piece cutting into
the flat ends of the nipples or the copper washer flattening and so
making a joint. Or in place of cutting threads of different pitch upon
the two nipples which are to be connected together by a socket a right-
handed thread may be cut upon one nipple and a left-handed thread
upon the other, and corresponding threads cut at the two ends of the
socket, so that by the screwing on of the socket the two nipples may
be similarly drawn tightly together. These ways of forming the joints

page_text: are chiefly required for the joints c, c, where the top horizontal tube of
the fire-box is connected with the several horizontal tubes above it, and
also for the joints d, d, where the top row of the tubes a are connected
to the steam pipe e. The fire-box is formed of wrought-iron tubes bent
into the desired form to make the sides of the box, and connected to
each other and the horizontal layers above by short vertical pipes. If
more than two vertical pipes are used to connect the horizontal ones
they must be screwed with similar threads at both ends, one end having
its screwed portion at least twice that of the other. In putting together
all the long ends are first screwed into the horizontal pipes as far as
they will go. The other tube is then put into position. The vertical
pipes are then screwed back again as far as the short thread will permit
them; they are then secured by caulking. The feed water is passed
into the bottom tube a, which is bent so as to pass entirely around the
bottom of the fire, its welded ends being brought together, as shewn at a¹.
The tube above it and likewise the top tube of the fire-box are similarly
bent round and their welded ends brought together. The welded ends of
the two intermediate tubes are not brought close up to one another, but a
sufficient but a sufficient space is left between them to allow of the
fire-box being supplied with fuel. f,f, are fire-bars for the fuel to rest
The tubes forming the boiler are surrounded by a double case of
wrought iron, g, g, the space between the cases being filled with vegetable
black or other suitable non-conducting material, but by preference I
employ the vegetable black as a very small thickness of this material
entirely prevents heat passing away through it. An opening is formed
through the casing for the fire-door, as shewn at h, Figure 2.
on.
The arrangement of compound engine I prefer to employ is shewn in
the Drawings. In each a high-pressure single-acting and a low-pressure
double-acting cylinder is employed with a chamber of suitable pro-
portion at the side the high-pressure cylinder is marked i and the low
pressure marked k.
In the engine shewn at Figure 1 a piston rod Z
from the piston of the low-pressure cylinder passes out through a stuffing
box at the bottom of this cylinder, and is attached to a cross head slide /,
from which a connecting rod passes to a crank pin m on the shaft n.
This shaft has, by preference, two other cranks upon it, the crank pins
of which are marked m¹, m², and these are each driven by a similar
arrangement of double cylinder engine. In cach engine the piston /*
for the high and low pressure, cylinder is made in one piece, the high-

page_text: and
pressure piston being so constructed as to fill the cylinder when at the
top of the stroke; the steam after being used in the high-pressure
cylinder is passed to the chamber, and from the chamber to the top
bottom or to the bottom only of the low-pressure cylinder. The steam
is, by preference, passed to and from the high-pressure cylinder by a
piston valve and to the low by an ordinary slide valve, but any suitable
valve arrangement may be employed, and I prefer that the valves should
be worked by eccentrics on the crank shaft and controlled by a link
motion in the usual manner. In this arrangement of cylinders the
high-pressure steam never comes in contact with the vegetable packing
in the stuffing boxes of the piston rods.
In the Drawings I have not thought it necessary to shew the valves
or valve gear, as the construction of these parts of an engine is well
understood.
In the arrangement of engine shewn at Figure 1 I prefer that the
low-pressure steam should be admitted both to the top and bottom of the
low-pressure cylinders, but if only one high and one low pressure
cylinder are used, as at Figure 2, I prefer to admit the low-pressure
steam to the bottom only of the low-pressure cylinder so that the up
stroke is made with the low pressure and the down stroke with the high
pressure steam only. The top of the cylinder is in this case connected
to the condenser so that any leak of steam into it may be recovered in
the condenser.
In Figure 1 the driving shaft n of the locomotive engine has upon it
near each end a toothed pinion which can be thrown in and out of gear
with a toothed wheel on axes o upon which are pinions gearing with
a ring of teeth upon cach of the driving wheels p, p, of the locomotive
engine.
In Figure 2 the piston of the low-pressure cylinder has two piston
rods 1, 1, passing up from it through passages cast at the sides of the
high-pressure cylinder and through stuffing boxes at the top of these
passages. One only of the piston rods is seen in the Drawings. The piston
rods are attached to a cross head slide A, and this by a connecting rod
drives a crank on the driving shaft n which is provided with a fly wheel.
The exhaust steam from the low-pressure cylinder is conducted away to
the condenser. In Figure 1 it is conducted to the top of the condenser
by the pipe q. This pipe has a branch q' upon it formed with a con-

page_text: tracted nozzle as shewn, so that any portion of the exhaust steam may
whenever desired be allowed to escape through this nozzle into the
chimney to increase the draft in the boiler furnace. In Figure 2 the
exhaust steam is passed into the bottom end of the condenser. The
joints between the cylinder covers and flanges are made by placing t
between them narrow washers of copper or other metal, say, of about
one-eighth of an inch or less, and compressing them to a perfect surface
by drawing the cylinder covers towards the flanges by bolts and nuts, or
in some cases very narrow projecting surfaces on the flanges or covers
are employed, the surface being sufficiently narrow and the bolts strong 1
enough to compress the narrow surface and so form a perfect joint; such
narrow projecting surface should enter a corresponding recess in order
that if the cover be taken off the cylinder the projecting surface may
always come to the same position when the cover is replaced.
I will now proceed to describe the condensers in which the steam 1
is condensed after being used in the engine. In the locomotive engine
I prefer to divide the condenser into two parts, there being one part
placed on each side of the engine, as is seen in the Drawings. These
condensers are composed of a series of small metal tubes placed in rows
and exposed externally to the atmosphere. The ends of the tubes
pass through plates into shallow chambers, where they are securely
fastened and made steam-tight. The steam enters the chamber at the
top or at the bottom, as the case may be, and the water formed by
condensation on the inner surface of the tubes flows out at the bottom
into the lower chamber, and from thence into the hot well, where it is 2
collected. Pipes are fixed at the ends of the condensers to clear them
of water when ascending or descending an incline. I have not thought
it necessary to shew these pipes, nor the hot well into which they
conduct the condensed water, nor have I thought it necessary to shew
the feed pump for pumping back such condensed water into the boiler,
as such feed pump may be of any ordinary construction. At the top
of the condensers relief valves loaded to a light pressure, say a pressure
of about one pound on the square inch, are provided; these prevent any
excess of pressure coming upon the tubes of the condenser in case the
steam is not all condensed, and yet they prevent the steam from blowing
off too readily and escaping from the condenser. The tubes of the
condenser I prefer to form of galvanized or tinned iron tubes, and I
provide about 150 square feet of tube. surface for every cubic foot

page_text: of water evaporated per hour in the boiler. The engine, boiler, con-
densers, tanks, and coal bunkers are carried upon a strong wrought-
iron frame made of angle iron. The locomotive engine shewn at
Figure 1 is carried on three wheels, the two driving wheels before
mentioned and another wheel for guiding. All the wheels are by
preference provided with india-rubber tyres protected from injury by
a flexible chain band constructed in the manner described in the
Specification of the Patent granted to me on the 23rd day of May,
1871 (No. 1379). The axle bearings of the front steering wheel are
connected to jaws upon a wheel plate or ring, around which is a spur
wheel; a pinion driven by a vertical shaft gears into the spur wheel, and
motion is imparted to this shaft by a worm and wheel. The wheel plate
is kept in its place by an internal flange embracing an angle iron ring
fastened to the main frame. This arrangement for working the steering
wheel is clearly shown in Figure 1; I would however state that I do
not confine myself to the employment of this special description of
steering gear, as other suitable arrangements may, if preferred, be adopted
in place thereof. In the engine shewn at Figure 1 the flue from the
boiler is so arranged that all the heated gases on their way to the
chimney have to pass the cylinders; or in place of this the cylinders
may have surrounding coils of pipe cast in with them, as shewn at
Figure 2, to be kept filled with steam from the boiler, and thus prevent
any condensation taking place in the cylinders when working the steam
expansively. Any suitable safety valve may be employed; the safety
valve I prefer consists of a conical valve pressed by a spring on the
back, and covered by a casing having two escape pipes that lead the
steam when blowing off into the condensers.
The valve is placed upon
the end of a siphon pipe filled with water to keep the valve cool, and
indicate when it blows off by becoming hot to the touch. The water
gauge is made with the usual glass tube, but in place of taps screw cocks
are used having long stuffing boxes to keep the packing cool, and the
glass is protected from breaking by two strong metal bars, one'upon
each side, connecting the ends and preventing them from bending
outwards when under great pressure. The boiler is provided with two
blow-off cocks, one for clearing it of water, and the other for relieving
the boiler from undue pressure. This cock is connected with the
condensers by the escape pipe from the safety valve. Both cocks are
provided with stuffing boxes placed at a distance from the steam to
protect the packing from the heat.. Each condenser is provided with
•

page_text: an air valve loaded to a slight pressure to relieve the condensers from
air, and also to act as a safety valve should they accidentally become
charged with steam to a greater amount than they are capable of
bearing. The steam pipe connections are made with sockets, the pipes
being screwed with right and left hand threads, or with differential
threads as herein-before described with regard to the boiler. One pipe
I form with a flat and the other with a conical end. The flange joints
I make with narrow surfaces or place narrow copper washers between
them, and draw the flanges together with bolts and nuts.
Having thus described the nature of my Invention, and the manner 1
of performing the same, I would have it understood that what I
claim is,―
1. The combined arrangement or construction of portable or locomotive
engines, substantially as herein-before described.
2. The construction of the steam boilers of locomotive or portable 1
steam engines, substantially as herein described.
3. The construction, substantially as herein described, of the fire-box
of the steam boiler.
4. The manner herein described of forming the joints d and other
steam pipe connections.
5. The employment of a narrow packing ring of copper or other
metal, or a narrow projecting surface as herein described for forming
a tight joint between the cylinder cover and flanges, and also where
flange joints are used in other parts of locomotive or portable steam
engines.
6. The construction of the condenser of portable and locomotive
engines, substantially as herein described, whereby the steam is retained
until condensed, and can yet blow off should any undue pressure come
upon the interior of the condenser.
In witness whereof, I, the said Loftus Perkins, have hereunto set a
my hand and seal, this Eleventh day of January, in the year
of our Lord One thousand eight hundred and seventy-two.
2

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