IMPROVEMENTS IN STREET AND LOCOMOTIVE ENGINES
Year: 1878

page_text: LETTERS PATENT to David James Lewin, of Poole, in the County of Dorset,
Engineer, for the Invention of "IMPROVEMENTS IN STREET AND
LOCOMOTIVE ENGINES."
OTHER
Sealed the 24th May 1878, and dated the 12th March 1878.
PROVISIONAL SPECIFICATION left by the said David James Lewin at the
Office of the Commissioners of Patents on the 12th March 1878.
DAVID JAMES LEWIN, of Poole, in the County of Dorsetshire, Engineer. "IM-
PROVEMENTS IN STREET AND OTHER LOCOMOTIVE ENGINES."
My Invention relates to improvements in locomotive engines for street and other
public tramways, and has for its objects the prevention of smoke, the absorbtion,
dissipation of the obnoxious fumes from coke and other fuels, with, by the same
means, a production of a suitable draught for the thorough combustion of fuel and
generation of steam.
Also my Invention provides for the constant and thorough condensation of
steam and the economical working of the engine, both in fuel and water, for con-
densing purposes.
To effect these objects the appliances I use are as follows:-I provide a suitable
fan, with which I exhaust the heated air gases from the smoke box of the loco-
motive boiler, and thus make a forced draught, by which a suitable quantity of air
is drawn through the fuel ou the fire-bars of the engine to cause thorough com-
bustion of the fuel and combustible gases and smoke. I especially make this fan
of so large and suitable a size that it is sufficient to thoroughly dilute the obnoxious
products of combustion after they have left the fire-box with pure air, so that they
are rendered comparatively cold and without smell. These mixed products of
combustion and pure air I then deliver underneath or at the sides of the tram car,
where they are further dissipated by the motion of the moving car, and are perfectly
inoffensive to and unnoticeable by passengers either inside or outside the car. 1
give motion to this fan either by friction or spur gearing driven from the axles of
19

page_text: the engine or car, or by using a pitch chain, gut, or belt suitable for the purpose;
or I may drive the fan by a small separate engine provided for the purpose.
I provide the boiler with a suitable chimney to cause a draught for raising
steam, so that the products of combustion have free egress upwards when standing
and the fan not in use. I place in the chimney also a throttle valve, which may
be actuated by the starting lever of the engine, so that the said valve will be
closed when the engine is set into motion and the fan begins to act, and vice
versa, the valve will be opened when the steam is shut off and the engine comes to
a standstill.
I provide for the thorough condensation of the steam by means of a series of
suitable tanks, through which the exhaust stean is passed inside small pipes or
between thin sheets of some good conducting metal. The condensing tanks are
divided into a series of separate compartments divided by non-conducting parti-
tions, so that the steam to be condensed passes through the tanks consecutively.
This arrangement always keeps some of the water in the last tanks as cold as
possible, thus always ensuring constant and thorough condensation. The whole of
the condensed steam I collect in a suitable tank or at the bottom of the condensing
tank, from when it is pumped back into the boiler, thus economizing fuel.
I further construct the cylinders of the locomotive in a suitable proportion for
a compound engine, using the boiler pressure direct in the smaller cylinder, and
then exhausting from it by further expansion into the larger cylinder. This is to
effect a maximum range of expansion with the steam, and hence the most econ-
omical rate of fuel combustion possible. I further add to these cylinders a valve
and pipe arrangement, so that these cylinders can either be used in conjunction as
just described for compounding, or when desired by the driver they can be dis-
connected and each cylinder be supplied with steam direct from the boiler. This
will be found very advantageous when the fullest possible power is required from
the locomotive to surmount steep gradients. I further add to the cylinders any
simple link valve motion, so that the range of expansion in the small cylinder can be
varied and controlled by the driver without effecting the point of cut-off in the
locomotive pressure or larger cylinder.

page_text: the said David James Lewin in the Great Seal Patent Office on the 12th
September 1878.
DAVID JAMES LEWIN, of Poole, in the County of Dorsetshire, Engineer.
PROVEMENTS IN STREET AND OTHER LOCOMOTIVE ENGINES."
'IM-
My Invention relates to improvements in locomotive engines for street and other
tramways, and has for its object the prevention of smoke, the absorption and dis-
sipation of the obnoxious fumes from coke and other fuels with, by the same means,
a production of a suitable draught for the thorough combustion of fuel and gene-
ration of steam.
Also my Invention provides for the constant and thorough condensation of steam
and the economical working of the engine, both in fuel and water for condensing
purposes.
To effect these objects the appliances I use are as follows:-I provide a suitable
fan, with which I exhaust the heated air and gases from the smoke box of the
locomotive boiler, and thus make a forced draught, by which a suitable quantity of
air is drawn through the fuel on the fire-bars of the engine to cause thorough
combustion of the fuel and combustible gases and smoke. I especially make this
fan of so large and suitable a size that it is sufficient to thoroughly dilute the
obnoxious products of combustion after they have left the fire-box with pure air,
so that they are rendered comparatively cold and without smell. These mixed
products of combustion and pure air I then deliver underneath or at the sides of
the tram-car, where they are further dissipated by the motion of the moving.car,
and are perfectly inoffensive to and unnoticeable by passengers either inside or
outside the car. I give motion to the fan either by friction or by spur gearing
driven from the axles of the engine or car, or by using a pitch chain, gut, or belt
suitable for the purpose; or I may drive the fan by a small separate engine pro-
vided for the purpose.
I provide the boiler with a suitable chimney to cause a draught for raising steam,
so that the products of combustion have free egress upwards when standing and
the fan is not in use. I place in the chimney also a throttle valve, which may be
actuated by the starting lever of the engine, so that the said valve will be closed
when the engine is set in motion and the fan begins to act, and vice versà, the
valve will be opened when the steam is shut off, and the engine comes to a
standstill.
I provide for the thorough condensation of the steam by means of a series of
suitable tanks, through which the exhaust steam is passed inside small pipes or
between thin sheets of some good conducting metal. The condensing tanks are
divided into a series of separate compartments divided by non-conducting parti-
tions, so that the steam to be condensed passes through the tanks consecutively.
This arrangement always keeps some of the water in the last tanks as cold as
possible, thus always ensuring constant and thorough condensation. The whole of
the condensed steam I collect in a suitable tank or at the bottom of the condensing
tank, from where it is pumped back into the boiler, thus economizing fuel.
I further construct the cylinders of the locomotive in a suitable proportion for
a compound engine, using the boiler pressure direct in the smaller cylinder, and
then exhausting from it by further expansion into the larger cylinder. This is to
effect a maximum range of expansion with the steam, and hence the most eco-
nomical rate of fuel combustion possible. I further add to these cylinders a valve

page_text: This
and pipe arrangement, so that these cylinders can either be used in conjunction, as
just described, for compounding; or when desired by the driver they can be dis-
connected, and each cylinder be supplied with steam direct from the boiler.
will be found very advantageous when the fullest possible power is required from
the locomotive to surmount steep gradients. I use in conjunction with the
cylinders a simple link valve motion, so that the range of expansion in the small
cylinder can be varied and controlled by the driver without affecting the point of
cut-off in the low pressure or larger cylinder.
And in order that my Invention may be the more clearly understood, I now
proceed to describe in detail my Drawings as attached hereto.
Fig. 1 is an end elevation of the locomotive with a section taken through the
smoke box B and the distributing fan A; Fig. 2 is a side sectional elevation
through the same part.
The fan A is preferably caused to revolve whenever the engine is in motion by
the spur gearing E, E, E, which enables the fan to revolve at a considerable speed;
but I may also use either friction gearing belts and pulleys or an independent
donkey engine, as may be most convenient.
The fan by its revolution draws all the noxious products of combustion out of
the smoke box B when the throttle valve of the chimney F is closed. This causes
an efficient and steady draught through the fire-grate to maintain steady com-
bustion and evaporation. This fan is made of so largo a size that it can draw
also a large quantity of pure air from the external atmosphere, which is thus
enabled thoroughly to dilute the obnoxious products of combustion. The hot gases
from the furnace are thus rendered cool, and their obnoxious components become
harmless and unnoticeable by extreme dilution with pure air. The centrifugal
force of the fan causes these mixed products of combustion and pure air to be
delivered through either one of the orifices G and G¹, according to the direction of
rotation of the fan, underneath or at the sides of the car, where they are further
dissipated by the motion of the moving car.
When the fan is not in action the throttle valve F in the chimney may be
opened, so that the products of combustion have free egress upwards when the
engine is standing.
Fig. 3 is an outside elevation of the series of condensing tanks C, C, C, C, which
are placed on the top of the locomotive boiler H, and connected to the cylinders by
exhaust pipes K, K². The exhaust steam is conducted from the cylinder through
the exhaust pipes K, K¹, to the lower cast-iron compartiment L. This compartment is
divided into sections by intermediate non-conducting partitions, between which the
bent U pipes D form the only connection. The exhaust steam is thus obliged to
pass from compartment L to compartment L', and so on by means of the successive
series of bent tubes D, first on one side of the tank, and then, by passing through
the connecting pipe M, to the other series of tanks on the other side until the
condensed steam is finally discharged at the pipe N. This arrangement of successive
isolated compartments in the condensing tank obliges each section to become heated
individually and in succession, so that the action of condensation will remain quite
perfect and regular so long as there is one compartment remaining cold.
The condensed steam is collected from the waste pipe N into a receiving tank
underneath, and is thence pumped back into the boiler to ensure economy.
And in order the better to define my improvements, I hereby wish it to be
understood that I claim,-
1st. The use of a fan in combination with a throttle valve which shall draw
away the products of combustion after they have passed the fire and shall mix
them with a considerable proportion of pure air in order to render them cold and
innoxious for the purpose and in the manner described.
2nd. The use of a condensing tank divided into a number of separate chambers
with condensing tubes therein, so that they shall become hot in succession and not

page_text: equally throughout, so as to ensure constant and thorough condensation for the
purpose and in the manner herein described.
In witness whereof, I, the said David James Lewin, have hereunto set my
hand and seal, this Twelfth day of September, in the year of our Lord One
thousand eight hundred and seventy-eight.
Witness,
S. P. WILDING,
Secretary of the City Patent Office,
23, Rood Lane,
Fenchurch St.,
London, E.C.
DAVID JAMES LEWIN. (L.S.)