Improvements in the Construction of Steam Draft or Tractor Engines applicable for Drawing all Kinds of Vehicles and for other purposes.
Year: 1898

page_text: Date of Application, 11th Oct., 1896
Complete Specification Left, 11th July, 1899-Accepted, 26th Aug., 1899
Date of Application, FiEN UCL,, 1030
Complete Specification Left, 11th July, 1899-Accepted, 26th Aug., 1899
PROVIDIUNAL DIECIFICATION.
Improvements in the Construction of Steam Draft or Tractor Engines
applicable for Drawing all Kinds of Vehicles and for other
purposes.
We, EDWARD ELLIS ALLEN, of 140, Stephendale Road, Fulham, in the County
of Middlesex, Engineer, and JOHN RENDALL, of Hays Lodge, 122, Loughboro'
Road, Brixton, in the County of Surrey, Gentleman, do hereby declare the nature
of this invention to be as follows:
1
Our invention consists of an entirely new arrangement and construction of
engine for draught or traction and other purposes or what is called in the
Locomotives or Highways Act 1896" a "light locomotive" designed expressly
to conform to all the conditions and requirements laid down in the said Act, as
also all the regulations of the Local Government Board respecting auto-motor
carriages.
"
A light locomotive as there defined, is "a vehicle propelled by mechanical
power which is under three tons in weight unladen and is not used for the purpose
of drawing more than one vehicle (such vehicle with its locomotive not exceeding
in weight unladen four tons) and is so constructed that no smoke or visible
vapour is emitted therefrom except from any temporary or accidental cause.'
The regulations as to these engines travelling forwards or backwards and as
to having two independent brakes" either of which shall lock two of the
wheels on the same axle require no special plans as these are ordinary mechanical
arrangements well understood.
"
But the point to which our invention more specially applies is that of prevent-
ing the escape of
smoke or visible vapour." To this end to avoid smoke we
employ liquid fuel and (inasmuch as steam of a pressure of 150 to 300 pounds
on the square inchi is now commonly employed a very high degree of expansion
viz. 10, 12, 15 or more times is required in order that the exhaust steam shall
be at or near atmospheric pressure and thus easily dealt with so that no visible
vapour is emitted or noise produced by the exhaust even if discharged direct
from the cylinders. Of course a higher pressure in the exhaust may be met
by a very large and weighty air or water surface condenser, or by superheating
the exhaust steam in order to render it invisible but any issue of hot vapour,
although not visible in the ordinary sense, must be very objectionable in crowded
thoroughfares. In order to provide against such defects, we use a special form of
engine, hereafter described, which allows practically of any degree of expansion
while retaining the simple form of a single cylinder with ordinary link motion
for varying the expansion and for reversing the engine, single guides and
connecting rod and with balanced slide or piston valves.
The water tube boiler we employ although in general form not new, has
inclined water tubes fixed at right angles to the tube plates ensuring good circula-
tion but has also a special arrangement for reducing the quantity of water carried
as hereinafter described, and as to the condenser, in order to increase its efficiency

page_text: and reduce its size weight and cost we employ an entirely new system using a
small air-compresser cylinder by which heat is generated which we use in jacket-
ting the main cylinders, afterwards expanding the compressed air in producing
cold to aid in the condensation of the exhaust steam as hereinafter described.
Thus by a new combination of the principles of thorough expansion of steam,
limitation of weight of water in boiler and thorough circulation, and by the use
of expanding air in the condenser we have produced an engine capable of meet-
ing all the requirements of the Locomotive Act of 1896 and the regulations of
the Local Board, the details of such arrangements being duly set forth in the
following description, that is to say:-the cylinders we construct double the
length of the stroke dividing them in the centre by an annular partition. In
each end of the said cylinders a piston works, the two pistons being united by
a trunk or cylinder which passes through the annular partition. Steam is
admitted alternately in the annular spaces on each side of the said partition and
being here more or less expanded by lap on the valve and the action of the link
motion passes to the respective ends of the cylinder acting upon the full area
of the pistons where it may be expanded to any desired extent, in proportion to
the area of the annular space and that of the whole cylinder. Ordinary slide or
piston valves may be used to regulate the admission and exhaust passages as
well as the equilibrium ones, or these latter can be made round the circum-
ference of the pistons, being opened and closed by a tappet action of the pistons
at the respective ends of their travel. A rotating or four way cock valve may
be employed in small engines. In some cases use may be made of the trunk
itself as a cylinder.
In this case a stationary piston is held in place in the centre of the cylinder
by a rod attached to the back cover of the cylinder such rod passing through
the rear piston of the trunk the piston rod working through the front cover of the
cylinder and being attached to the fore piston of the trunk. Communication is
made between the inside of the trunk and the respective ends of the cylinder
by making the said trunk double, having passages round its circumference one
half opening out into one end and the other half into the opposite end, by this
arrangement the trunk space is practically added to that of the cylinder as room
for expansion without any extra valves, the stationary piston and its rod being
alone added or the said trunk may be used as (what may be called) an inner
jacket into which steam from the boiler or hot air can be admitted for super-
heating or drying the steam during expansion, the cylinder itself and valve
chest being also jacketted. The steam or hot air to the trunk in this case would
be admitted through small tubes passing through one or both pistons and one
or both covers of the cylinder. By this arrangement any degree of expansion
can be obtained, each engine having but a single moving piston rod, single
connecting rod and one set of guides. When required live steam can be admitted
to the full area of the pistons for temporally increasing the power.
No separate expansion valve is necessary, two eccentrics with link motion
for reversion or similar arrangement being alone required. In some cases we
provide a small air compresser for the purpose of more effectually working a
tubular surface condenser by which the exhaust steam may be condensed, the
water being returned to the boiler. The compressed air will first be heated by
its compression and may be used in the jacketting of the cylinders, valves and
trunk and afterwards (having parted with its heat) will or may on its subsequent
expansion be used in the condenser to aid in the condensation of the exhaust
steam. The condenser may be of the usual kind, that is composed of small brass
tubes, the exhaust steam being allowed to flow through them and the expanding
air circulating amongst them, or the steam may be on the outside of the tubes
and the expanding air be passed through them.
Our improvements in water tube boilers are designed to economise in the
construction of the boiler, to avoid the destructive wear of the tubes, to diminish
the bulk of water carried and to provide for the more easy escape of steam from

page_text: the tubes than when they are horizontal. We form the boiler rectangular in
plan similar to a locomotive fire box so that the tube plates can be effectively
stayed to the outer shell and the shell plates to each other. Water tubes are
arranged both fore and aft and across in alternate courses and in the ordinary
way would be in horizontal position being secured at right angles to the tube
plates. Through the centre of each tube or in as many as required we pass stay
bolts so tying together the outer shell plates but in order to reduce the water
space we surround these stays with hard wooden cylindrical tubes or tubes of
asbestos or other material so as to occupy the space and leave only an annular
space of any width required for the water, the tubes through which stay bolts
do not pass being also partially filled by the said wooden or other cylinders. In
order to aid the escape of the steam from the water and the tubes, we arrange
them in an inclined position and to this end while fixing them at right angles
with the tube plates (assuming the boiler to be in the shape of a cube) we virtually
stand it preferably about 120 from the horizontal upon one corner, the tubes in
both directions rising from this corner where their ends are lowest to the angle
required. In order to enclose the fire grate or space for oil burner or other fuel
we continue the tube and outer shell plates of the boiler down to the horizontal
linc, such prolongations being duly stayed by the usual short water space stays.
The crown plates of these boilers may be dome shaped or be made horizontal
and duly stayed, and the outer casing of boiler, to prevent radiation, containing
asbestos or other non-conducting material as a packing may be made rectangular
so as to conceal the inclined position of the boiler if desired or the boiler may
be fixed to the platform of the engine with two of its opposite angles in the
centre line of the platform or engine framing and so rake fore or aft, thus taking
up less space than if covered with a vertical casing, and presenting a lighter
and more characteristic appearance for the purpose required.
Our improvements in the mode of attaching the draft engines to vehicles
consists in making clips of solid rubber or of springs enclosed in leather for
attaching the rods or couplings to the splinter bar of the fore carriage of vehicles
so that such vehicles may follow the engine but be started without jerking, or
the tail end of the engine and frame is made so that it may carry the fore part
of the following vehicle (upon the fore bottom carriage being removed) proper
provision being made for the suitable support upon springs of such additional
weight on the driving wheels of the engine, such support being made adjustable
as to height, the perch bolt being used for uniting the engine and vehicle.
Dated this 11th day of October 1898.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
Improvements in the Construction of Steam Draft or Traction Engines
applicable for Drawing all Kinds of Vehicles and for other
purposes.
EDWARD ELLIS ALLEN, of 140, Stephendale Road, Fulham, in the County
of Middlesex, Engineer, and JOIN RENDALL, of Hays Lodge, 122, Loughboro'.
Road, Brixton, in the County of Surrey, Gentleman, do hereby declare the nature
of this invention, and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
Our invention consists of an entirely new arrangement and construction, of
engine for draught or traction and other purposes or what is called in the

page_text: "Locomotives on Highways Act 1896" a "light locomotive" designed expressly
to conform to all the conditions and requirements laid down in the said Act, as
also all the regulations of the Local Government Board respecting auto-motor
carriages.
A light locomotive as there defined, is "a vehicle propelled by mechanical
power which is under three tons in weight unladen and is not used for the purpose
of drawing more than one vehicle (such vehicle with its locomotive not exceeding
in weight unladen four tons) and is so constructed that no smoke or visible
vapour is emitted therefrom except from any temporary or accidental cause.
The regulations as to these engines travelling forwards or backwards and as
to having two independent brakes" either of which shall lock two of the
wheels on the same axle require no special plans as these are ordinary mechanical
arrangements well understood.
65
But the point to which our invention more specially applies is that of prevent-
ing the escape of "smoke or visible vapour." To this end to avoid smoke we
employ liquid fuel and inasmuch as steam of a pressure of 150 to 300 pounds
on the square inch is now commonly employed a very high degree of expansion
viz. 10, 12, 15 or more times is required in order that the exhaust steam shall
be at or near atmospheric pressure and thus easily dealt with so that no visible
vapour is emitted or noise produced by the exhaust even if discharged direct
from the cylinders. Of course a higher pressure in the exhaust may be met.
by a very large and weighty air or water surface condenser, or by superheating
the exhaust steam in order to render it invisible but any issue of hot vapour,
although not visible in the ordinary sense, must be very objectionable in crowded
thoroughfares.
In order to provide against such defects, we use a special form of engine,
hereafter described, which allows practically of any degree of expansion while
retaining the simple form of a single cylinder with ordinary link motion for
varying the expansion and for reversing the engine, single guides and connecting
rod and with balanced slide or piston valves.
We will proceed to describe the invention by means of the accompanying draw-
ings in which Fig. 1 is a side elevation and Fig. 2 a plan of a light locomotive
constructed according to the invention.
Fig. 3 is a plan of the under carriage.
Fig. 4 is a horizontal section of the boiler.
Fig. 5 is a vertical section of the boiler.
Fig. 6 is a vertical section of part of the boiler showing a modification.
Fig. 7 is a vertical section of the condenser and Fig. 8 is a sectional rear view
of the same.
Fig. 9 is a section of a cylinder fitted with piston valve and Fig. 10 is a
section of a similar form of cylinder but fitted with a balanced slide valve.
Fig. 11 is a longitudinal section and Fig. 12 a sectional end view of the trunk
suited to the arrangement shown in Figures 9 and 10 when the interior thereof
is used as an additional steam cylinder.
Figures 13 and 14 are diagrammatic views of the two cylinders when arranged
as a quadruple expansion engine working cranks at right angles.
Figures 15 and 16 are diagrammatic views of a modified form of two cylinders
arranged as a quadruple expansion engine when a longer stroke is required.
Figures 1, 2, 3, 5 and 6 are drawn to one scale Figures 4, 7 and 8 are drawn to
twice the said scale and Figures 9, 10, 11 and 12 are drawn to a still larger scale.
Like parts are indicated by similar letters of reference in all the figures.
The water tube boiler as shown in Figures 1, 2, 3, 4, 5, 6 is rectangular in
cross section and raked backwards somewhat from the vertical position. It
consists of an outer casing a having an inner casing or fire box 6 through which
pass the products of combustion. From the centre of the upper part of this
inner casing or fire box b is a flue c which passes to the centre of the top of the
boiler, this flue extends on the exterior of the boiler and is terminated by a cap c¹.

page_text: The water tubes are arranged at right angles to the sides of the inner casing
or fire box b as shown in Figures 4, 5 and 6, and are consequently at a slight
inclination as seen in Figures 5 and 6.
In Fig. 6 we have shown the flue c* of larger diameter than that of the flue c
in Fig. 5 and it is provided with a number of extra tubes which act as a super-
heater for the steam.
The stays e of the outer shell of the boiler may consist of hollow tubes, as
shown in Fig. 4. These may terminate in a casing e common to all as shown
on the left hand side of Fig. 5 or in a series of tubes e² one of which is shown in
Figures 4 and 5 which series are again united at their upper and lower ends by
large tubes e see Fig. 5 equal or nearly equal to the united areas of the tubes e³.
Through these tubes 3 or through the casing e¹ the products of combustion
may be made to pass when of a higher temperature than the water in the boiler
and thus partially utilize heat which would otherwise be lost and finally the
products are discharged in any direction by the pipes e, e, e, e².
The water tubes d form struts for the inner casing or fire box b. They are
screw threaded at their ends and are provided with two nuts es at each end, one
on each side of the inner casing b.
The water tubes d which have no stays passing through them have rods f
of wood or other suitable material passed through them to lessen the water
space.
The crown of the boiler a¹ may be flat as shown if properly stayed but it may
in some cases be of circular or dome form. The cap or hood c¹ of the flue may
be connected to a pipe passing to the lower part of the engine or it may be
connected with the casing e¹ enclosing the open ends of the hollow stays e. The
products of combustion will therefore pass through the hollow stays e and will
help to heat the water. In some cases ordinary stay bolts e* may be passed
through the water tubes as shown in Fig. 4.
The surface condenser is arranged at the rear of the light locomotive across
the whole width of the framing as seen in Figures 1 and 2.
The exhaust steam from the cylinder passes through the pipes h and enters
the exterior casing g of the condenser which is divided into several compartments
by means of the partitions gl shown in Fig. S. It then passes through some of
the small inclined brass tubes which are carried by the plates g3 after which
it returns through another set of tubes arranged in a smaller compartment and
finally reaches the middle compartments by which time it is completely condensed.
The tubes are inclined so as to be easily freed from the water or condensed
steam which falls into the hot well i from which the boiler is supplied. The
condenser is preferably made so that it may be readily removed from the casing
for cleaning and repairs. Expanding compressed air enters the condenser casing
by the pipe and develops a considerable degree of cold. It comes into contact
with the tubes at right angles to their length and will more or less effectually
condense the exhaust steam and absorb the latent heat of the steam thus causing
the return of the whole or nearly the whole of the condensed steam to the boiler.
The feed pump j draws the water from the hot well by the pipe and forces
it into the boiler through the pipe . The feed pump and the oil pump are
both operated by a rod 2 connecting the cross head with the crank portion j
of the shaft k as seen in Fig. 3.
The oil pump seen in Fig. 3 is connected with the oil tank by means of
the pipe and supplies the burner in the furnace by the pipe the quantity
taken by the oil pump 7 being regulated by a valve operated by the hand
wheel see Fig. 1. When the oil is allowed to flow from the oil tank to the
burner it passes through the pipe the quantity being regulated by a valve
operated by the hand wheel 1.
The air compressing pump m, Fig. 3, is driven by means of a crank on the
shaft and forces air into the compressed air reservoir m¹ or by a pipe m² direct

page_text: into the casings m³ surrounding the cylinders and valves and constituting their
jackets as shown at Figures 1 and 2. When necessary such reservoir m' or
casing is fitted with reducing valve or valves for supplying the compressed air
at any desired pressure according to what is required, for jacketing the cylinders,
supplying oil fuel to the burner and for spraying the said oil. The compressed
air after passing through the cylinder jackets by the pipe m³ and becoming
partially cooled passes through the pipe to the steam condenser g and passes
away by the pipe go to the casing round the air compressor m and finally escapes
through the pipe go to the furnace n. In Fig. 3 the compressor pump m is shown
surrounded by a casing or enlargement g* of the air exhaust pipe 95 such casing
being separated from the compressed air reservoir m¹ by non conducting material
not shown which surrounds it.
We will now describe the cylinders shown in Figures 9 and 10, and in the
diagrams Figures 13 and 14. In all these figures the operation of the pistons
is the same but in Fig. 9 we have shown piston valves and Fig. 10 we have
shown a balanced slide valve.
The cylinder o is divided into two parts by a ring o¹ fitting a trunk o2 which
latter has at each end thereof a piston o³ fitting the interior of the cylinder.
Steam is admitted to one of the annular spaces of and at the end of the stroke
it expands into the cylinder o.
It will be understood that when the steam is expanding into one end of-the
cylinder, high pressure steam is being admitted to the annular space o' on the
other side of the dividing ring o
This form of cylinder is suitable for short stroke quick rotating engines and
by employing two cylinders of suitable size as shown in Figures 13 and 14 they
may act as a quadruple expansion engine, the area of the annular space o** in
Figure 14 being about double the full area of the piston o in Fig. 13 and
the space o in Fig. 14 being about double the area of the annular space o**.
Figures 15 and 16 show a modification of the arrangements of cylinders shown
. in Figures 9 to 14 and more suited to longer stroke engines and a slower rate
of revolution.
In these figures the cylinders have a single piston p1 with a trunk 22 on
one side thereof with the connecting rod p³ connected thereto at p. In this
form of cylinder no guides are required. As shown in the diagrams the cranks
are arranged at right angles and the cylinders are made proportional for quad-
ruple expansion, the area of the piston in Fig. 16 being about double the area
of the annular space of its own cylinder which in turn is double the area of the
piston in Fig. 15 and this latter is double the area of the annular space in the
smaller cylinder.
Figures 11 and 12 show details of a trunk suited to the arrangement of cylinder
shown in Figures 9 and 10 when it is desired to use the interior of the trunk
as an extra steam cylinder. The trunk q has an internal fixed piston q' attached
to a piston rod q passing through a stuffing box q³ in one of the pistons and
connected to the end of the cylinder.
The trunk has two sets of passages arranged in its walls, each set com-
municating from one end of the main cylinder to the opposite side of the fixed
piston q¹. The steam expanding from the annular spaces into the cylinder
proper will also expand through the passages q into the opposite end of the
trunk and will be exhausted through the same passages.
The under carriage works are shown in Fig. 3. The engine crank shaft r
has two cranks at right angles and gives motion to the intermediate shafts by
toothed gear wheels s¹ the latter being attached to the double driving or
differential gear 2. The intermediate shaft s has a chain wheel at each end
thereof which chain wheels are connected by means of chains to the chain wheels t
mounted on the driving and carrying wheels t¹. The small shaft k for working
the air compressor and feed and oil pump placed under the steam condenser is

page_text: driven from the crank shaft r by toothed gearing and either of which.
may be put in action by means of friction clutches operated by a lever at
the back of the drivers seat but not shown in the drawings.
The front wheels u are steered by means of levers a connecting rods u² and
bell crank lever ³, link u lever shaft and handle in the usual manner
The driver's seat is arranged over the oil tank and small water tank v.
The steam from the boiler is supplied to the cylinders by pipes y the stop
valve being operated by the lever y'.
4
The band brakes we are worked by foot lever w¹ cross shaft w and rods w³ one.
on each side of the engine.
The starting stopping and reversing is effected by the ordinary link motion.
worked by the lever with quadrant across shaft and rods a
In Fig. 2 we have shown the pipe which conveys water from the water
tank to the hot well the quantity being regulated by the valve
The compressed air from the reservoir m¹ may if desired be supplied to the oil.
tank by the small pipe 70 with regulating valve 17 and press upon the surface
of the oil and thus feed the burner in the furnace by the pipe 5 (Fig. 1). In
this case a second pipe proceeds from the air reservoir m' to the furnace for
spraying the oil by means of compressed air.
This is regulated by a valve m¹ which is operated by the driver by means of
a lever and connecting rod not shown. Steam may however be employed for
spraying the oil if desired.
When once adjusted many of these regulating valves will not require altera-
tion except under special circumstances but they are all brought within easy
reach of the drivers seat.
In some cases the drivers seat will be arranged at the back of the boiler which
would necessarily change the position of all the pipes and levers although similar
connections would be made answering the same purposes as those shown.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, we declare that
what we claim is:-
1. In a light locomotive a boiler of a square or rectangular cross section and
raking fore and aft substantially as herein shown and described and for the
purpose stated.
2. In a light locomotive a raking boiler of square or rectangular cross section
and having two of its opposite angles in a line with the centre of the engine
substantially as herein shown and described and for the purpose stated.
3. In a light locomotive the combination of a crank shaft, an air compressor
operated by said crank shaft, a compressed air reservoir connected with a casing
surrounding the cylinders and valve chests and means for conveying said com-
pressed air from the cylinder casing to the steam condenser, substantially as herein
shown and described and for the purpose stated.
4. In a light locomotive, the combination of an air compressor, oil pump and
feed pump all driven from a supplemental crank shaft driven from the main
driving shaft by means of change speed gear, substantially as herein shown and
described.
5. In a light locomotive the combination of a water tube boiler of rectangular
shape, hollow stay bolts passing through said water tubes, and tubes or a common
casing into which said stay bolts open at their ends and through which the
products of combustion pass from the flue, substantially as herein shown and
described and for the purpose stated.
6. In a steam condenser for a light locomotive the combination of a number
of tubes arranged in a raking square or rectangular compartment subdivided
into smaller compartments, an outer casing having an inlet for the steam and
an inlet and exit for compressed air substantially as herein shown and described.
7. In a light locomotive an engine consisting of two cylinders in each of

page_text: which the steam is allowed to expand twice thus forming a quadruple expansion
engine, substantially as herein shown and described.
8. In a light locomotive, the combination of a raking rectangular boiler carry-
ing the cylinders, a main driving shaft, a supplemental cranked shaft, driven
from the main shaft, for the purpose of operating the air compressor, oil pump
and feed water pump, an intermediate divided shaft driven from the main
driving shaft and provided with a differential gear, chain wheels arranged at
each end of the intermediate shaft driving the driving wheels by means of chains
and chain wheels substantially as herein shown and described.
9. In a light locomotive, the peculiar combination and arrangement of parts
enabling compressed air from a compressed air reservoir to be used for jacketing
the cylinders and valves, the supply of oil from the oil tank to the burner, the
spraying of the oil, the cooling of the condenser tubes by expansion, for cooling
of the compressor pump and for increasing the draft in the flue, the compressed
air being regulated by reducing valves or stop cocks substantially as herein
shown and described.
1111
TL 1000
HARRIS & MILLS,
· 23, Southampton Buildings, London, W.C., Agents.