IMPROVEMENTS IN STEAM ENGINES AND CONDENSERS FOR TRAMWAY VEHICLES AND FOR OTHER Denna
Year: 1881

page_text: LETTERS PATENT to Thomas Robertson, junior, of Glasgow, in the County of
Lanark, North Britain, Engineer, for an Invention of "IMPROVEMENTS IN
STEAM ENGINES AND CONDENSERS FOR TRAMWAY VEHICLES AND FOR OTHER
Denna "
PROVISIONAL SPECIFICATION left by the said Thomas Robertson at the
Office of the Commissioners of Patents on the 15th January 1881.
THOMAS ROBERTSON, junior, of Glasgow, in the County of Lanark, North
Britain, Engineer. "IMPROVEMENTS IN STEAM ENGINES AND CONDENSERS FOR
TRAMWAY VEHICLES AND FOR OTHER PURPOSES."
The said Invention relates to improvements in steam engines for tramway
vehicles and for other purposes, and also in the means for condensing the exhaust
steam therefrom.
According to the said Invention a high pressure cylinder and a low pressure
cylinder, to which the exhaust steam from the high pressure cylinder is led, are
arranged in convenient proximity, in the case of tramcar vehicles preferably side
by side beneath the vehicle, and a vacuum or partial vacuum is produced on the
exhaust side of the piston of the high pressure cylinder by means of a jet of live
steam from the boiler, which is led or injected into the pipe or passage through
which the steam is exhausted from the high pressure cylinder to the low pressure
cylinder, the said jet of live steam being preferably injected at or before the orifice
of the said exhaust pipe or passage from the high pressure cylinder, where it
opens into the valve casing of the low pressure cylinder, the said injection taking
place through an orifice or orifices around the said passage or pipe, so inclined as to
inject the steam in an inward or cone-like direction in front of the said passage or
pipe.
The Invention further consists in an arrangement for counterbalancing the
pressure of the incoming steam upon the back of the slide valve of steam engines.
According to this part of the Invention there is a cylinder at each end of the valve
casing closed at their outer ends, one of them being furnished with a stuffing box
for the passage of the valve spindle. Upon the said spindle are two pistons or
plungers, one working closely in each of the said cylinders, so that their inward
sides towards the valve are open to the incoming steam. The said steam, by

page_text: pressing equally on these pistons or plungers on either side of the valve counter-
balance the pressure of the steam on the back of the said valve entirely, or to a
great extent. A valve of this kind may be used as the inlet valve for steam to
the brake cylinder. Its spindle will be acted upon by a governor, so that when a
definite speed has been attained the valve will be opened and steam admitted to
apply the brakes.
The Invention consists further of the following means for assisting in condensing
the exhaust steam as it passes after having performed its work in the engine to the
condensing tank :-There is formed around the pipe or passage through which this
exhaust steam passes a casing, the interior of which communicates with the interior
of the exhaust pipe or passage by orifices preferably inclined in the direction
which the exhaust steam takes to the condensing tank. Into this casing air is
injected or forced by a fan or other apparatus worked from any convenient part of
the engine, the said air passing in thin streams through the aforesaid orifices, which
streams meeting in a cone-like form in the exhaust passage or pipe greatly assist
in condensing the exhaust steam passing therethrough. More than one of these
casings may be used situated at different parts of the exhaust pipe or passage. A
similar air casing may be applied around the end or nozzle of the exhaust pipe or
passage, at the part or nozzle inside the condensing tank, whereat it discharges the
steam into the said tank. In this case, in addition to the inclined orifices for
admitting the air to the exhaust passage or pipe, a slit or orifice or orifices, pre-
ferably inclined inwards, may be formed around the outlet orifice of the exhaust
nozzle, so that a stream of air is forced through the said orifice or orifices, preferably
in a conical stream, in front of the said outlet orifice of the exhaust nozzle, which
is surrounded by a conical casing open at top and bottom and wide at the top,
decreasing downwards to below the outlet nozzle and then widening outwards
again, a deflecting cone shape piece being situated at its lower opening so as to give
a current of condensing water.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Robertson in the Great Seal Patent Office on the 14th July
1881.
THOMAS ROBERTSON, junior, of Glasgow, in the County of Lanark, North
Britain, Engineer. "IMPROVEMENTS IN STEAM ENGINES AND CONDENSERS FOR
TRAMWAY VEHICLES AND FOR OTHER PURPOSES."
My said Invention relates to steam engines for tramway vehicles, and for other
purposes, and also in means for condensing the exhaust steam therefrom.
A high pressure cylinder and a low pressure or expansion cylinder, to which the
exhaust steam from the high pressure cylinder is led, are employed, these cylinders
being arranged in convenient proximity, they being, when used for tram cars,
preferably arranged side by side beneath the vehicle. A vacuum or a partial
vacuum is produced on the exhaust side of the piston of the high pressure cylinder
at such times as extra power may be required by means of a jet of live steam from
the boiler, which is injected into or caused to pass through a contracted passage or
orifice or orifices in the pipe or passage through which the steam is exhausted from
the high pressure cylinder, the said steam so injected also assisting in driving the
piston of the low pressure engine.
My Invention consists further of the following means for condensing the exhaust
steam as it passes to the condensing tank or trap after having performed its work
in the engine. A casing is formed or placed around the pipe or passage through
which this exhaust steam passes, the interior of the said casing communicating with
the interior of the exhaust pipe or passage by orifices, preferably inclined inwards
in the direction in which the exhaust steam takes to the condensing tank or trap.
Into this casing air is forced, the said air passing in thin streams through the
aforesaid orifices, and greatly assisting in and almost completely condensing the
exhaust steam. Such casings may be applied at any desired part or parts of the
exhaust pipe or passage, and also at the part or nozzle whereat it discharges
the exhaust steam into the tank or trap in which the said exhaust steam is received
for condensation.
And in order that my said Invention may be properly understood, I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
accompanying Drawings and to the letters and figures marked thereon, that is to
Bay :-
Figure 1 is a plan of an arrangement of the engine of a tram car, shewing my
improvements combined therewith; Figures 2 to 13 are details and modifications,
as hereinafter described.
A is a high pressure cylinder, and B is a low pressure or expansion cylinder, into
which the exhaust steam from the cylinder A is led by the pipe a. Into this pipe
a jet of live steam from the boiler is led by the pipe c, and injected, preferably at
or before the orifice of the said exhaust pipe or passage a, when it opens into the
valve casing b of the low pressure or expansion cylinder B, so as by the force of its
injection to produce a vacuum or a partial vacuum in the said exhaust pipe.
Figure 2 is a longitudinal section of a part of the valve casing and exhaust pipe at
this part drawn to an enlarged scale. The exhaust pipe a from the high to the
low pressure. cylinder terminates in a nozzle piece a², which is surrounded by a
casing d, having a space between its interior and the exterior of the nozzle a³, the
said space receiving live steam from the boiler by the pipe c, which steam is
injected through the inclined or cone like passage or orifice d² between the end of
the nozzle a² and the casing d in an inward or cone like direction in front of the

page_text: said nozzle a², as indicated by the dotted lines. The pipe c will be furnished with
a cock, which may be operated by or like the ordinary steam inlet valve from the
front of the engine, and when, in going up hill, or on other occasion, greater power
is required, this valve is opened, the steam being injected as described, will greatly
aid or supplement the power of the engine by creating the aforesaid vacuum or
partial vacuum in the pipe a, and overcoming the back pressure on the exhaust side
of the piston of the high pressure cylinder A, and at the same time assisting
in driving the piston of the low pressure cylinder. Other forms of injecting
arrangements than those shewn in Figure 2, which will produce the vacuum or
partial vacuum in the exhaust pipe, may be employed. Figure 3 shews another
form of injector for this purpose. a is the exhaust pipe or passage from the high
pressure cylinder, and c is the steam inlet pipe from the boiler, which terminates
in a nozzle c², through which the steam is injected to create a vacuum or partial
vacuum in the pipe or passage a. In order to prevent the live steam admitted by
the pipe c from passing into the high pressure cylinder when the inlet port to the
low pressure cylinder is closed a valve a³ may be provided, as shewn in Figure 2,
which valve opens toward the low pressure cylinder to allow free passage for the
exhaust steam from the high pressure cylinder, but which will close and prevent
the passage of live steam to the exhaust side of the piston of the high pressure
cylinder when the inlet port of the low pressure cylinder is closed. The exhaust
pipe E leads from the cylinder B to the condensing tank F, either directly or it
may, as shewn, led first into a trap f, and any uncondensed portion of the exhaust
steam be caused to pass therefrom into the condensing tank F by the pipe g; or it
may be led by the continuation g² of the said pipe g to the furnace, a piston or
other valve g³ being operated by a rod from the front of the engine to open
communication between the chamber f, and either the passage g to the tank For
the passage g² to the furnace as may be desired. Around a portion of the length
of the pipe E is a casing k formed around or fitted upon the said pipe so as to
constitute an annular passage ² between its interior and the exterior of the said
exhaust pipe E. This casing k may be either a simple casing fastened on to a
part or parts of the exhaust pipe E, as illustrated in section respectively, with
respect to an iron and a copper exhaust pipe in Figures 4 and 5, or the said
casing k may contain an inner pipe or passage e, which forms a continuation of the
exhaust pipe, as illustrated in longitudinal section in Figure 6, which last
mentioned form is that shewn in Figure 1. A cone piece e³ may be provided to
break up the steam as it enters this continuation e of the exhaust pipe, as will be
seen by reference to these said Figures 4, 5, and 6. Orifices in the pipe E or its
continuation e give communication from the interior of the casing k to the interior
of the said pipe E (as in Figures 4 and 5) or its continuation (as in Figure 6).
These orifices may be holes or slits or cuts of any size, and in any suitable
number and arrangement, but they are preferably inclined inwards, as shewn in
Figure 4, in the direction in which the exhaust steam passes along the pipe E.
As shewn in Figures 4 and 6 the said orifices are holes formed by drilling, and in
Figure 5 they are slits formed by sawing, but other suitable means of making
these orifices may be adopted. Into the space ², between the interior of the
casing and the exhaust pipe or its continuation, air is injected or forced through
the inlet pipe by a fan or a pump, the said air passing in thin streams through
the said orifices k³, which streams meeting (preferably in a cone-like form) in the
exhaust passage or pipe E greatly assist in condensing the exhaust steam passing
therethrough and creating the necessary vacuum in the pipe or passage E. One or
any number of these casings k may be situated at any convenient part of the
exhaust pipe or passage. Figure 7 illustrates a modified form of such casing. The
exhaust steam pipe enlarges at E2, and is there surrounded by a casing k, similar to
those herein before described, and the exhaust steam after passing through a number
of small tubes enters the continuation of the exhaust passage at E³, which is also
surrounded by an air casing k, similar to those hereinbefore described. Figure 8
is an end view of one of the flange plates in which the tubes are fixed;

page_text: Figures 9 and 10 shew in sections at right angles the one to the other a
variation in this form of the adaptation of my Invention, wherein the casing k
similar to those hereinbefore described is upon the exhaust pipe E at the part of
the said pipe just before it opens into a casing m fixed upon the trap f (which in
this case is shewn as formed by partitioning off the end of the condensing tank F),
from the casing m, the steam passes through the tube and into the casing m²,
and thence into the trap f. A similar air casing to that hereinbefore described
may be applied around the end or nozzle of the exhaust pipe or passage inside the
tank F or the trap f. In Figure 4 such an air casing is shewn applied to the said
end or nozzle. The casing, and air passages ³, and air supply are analogous
to those herein before described, and a slit or orifice or orifices p is or are or may
be formed around the outlet orifice of the exhaust nozzle, so that a stream of air
is forced through the said orifice in a conical stream in front of the outlet orifice of
the exhaust nozzle. A similar orifice is shewn at p in connection with the casing /
in Figure 7, and also with the casing in Figure 6. Where the air casing is used
at the end of the exhaust pipe when it enters the trap f the arrangement,
Figure 4, will answer, but where the said air casing is used at the nozzle of the
exhaust steam pipe which enters the water tank F, the end of the said nozzle is
surrounded by a conical casing q open at top and bottom, and leaving a space
between itself and the nozzle, as shewn in Figure 11, it being wide at top,
decreasing downwards to below the nozzle, and then widening outwards again.
A deflecting cone shaped piece r is situated at the lower opening of the casing q so
as to give a current of condensing water. There may be a hole (provided or not
with an inlet valve) in the exhaust pipe, as indicated at w, for giving free com-
munication between the outside atmosphere or above the water space of the
condenser to prevent the water in the tank from being drawn into the cylinder
when the steam is shut off. The fan or pump which supplies air to the air casing
or casings k may be of any suitable or convenient construction, and I do not limit
myself to the use of any particular form of pump or fan; a suitable form of pump
is shewn in Figures 12 and 13. It is a double acting pump, air being drawn into
the pump through the perforated roset and through one or other of the valves t³,
and discharged through one or other of the valves u² into the chamber u. From
this chamber two passages open, each having a valve, the one at u³ weighted
according to the pressure at which the air is to be supplied from the said chamber u
to the air casing or casings (k), the air passing from the said passage u³ by the
branch us through the cock u (Figure 1) by the branch pipes k to the air casings k.
The cock u may be a three way cock or valve operated by a rod from the front
of the engine so that air may be supplied to or shut off from the casing or
casings k, as may be desired. The other of the passages u* from the chamber u
of the pump opens to the atmosphere, and is provided with a valve weighted, Bo
that should the air in the chamber u attain a greater pressure than is desirable it
will blow off by this valve. The air casings k may be used upon the exhaust pipes
or passages of other than expansion cylinders. The air passing into the condenser will
escape through through a pipe, opening, or passage provided therein for the purpose.
Although I have described but one low pressure or expansion cylinder, two or
more such cylinders may be used if desired, in which case the pipe c for live steam
will be led to the exhaust pipe or passage from the high to the first low pressure
cylinder, and the air casing or casings (k) will be upon the exhaust pipe or passage
from the last low pressure cylinder.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode or manner in or under which the same is or may
be used or practically carried into effect, I would observe in conclusion that I
wish it to be understood that I do not claim generally in steam engines the
admission of steam from the boiler to the low pressure cylinder, nor do I claim
generally the condensation of the exhaust steam of steam engines by the direct
contact of air therewith, nor do I limit myself to the precise details hereinbefore
described and illustrated in the accompanying. Drawings, as the same may be

page_text: varied without departing from the nature of my Invention, but what I consider
to be novel and original, and therefore claim as the Invention secured to me by
the hereinbefore in part recited Letters Patent is,―
First. The improvement in engines for tramcars or for analogous purposes
consisting of a high and low pressure or expansion cylinder or cylinders in com-
bination with means for injecting (when additional power is needed) live steam
into, before, or in front of the pipe or passage through which the steam is exhausted
from the high pressure cylinder to the low pressure cylinder, or to the first low
pressure cylinder where more than one is used through such a contracted passage
or orifice or orifices as to create a vacuum or partial vacuum in the said pipe or
passage, and on the exhaust side of the piston of the high pressure cylinder, the
said live steam supplementing the power of the exhaust steam in the low pressure
cylinder, essentially as herein before described.
Second. In compound engines, providing at the end of the exhaust steam pipe
or passage from the high pressure cylinder to the low pressure cylinder at the end
of the said pipe or passage which opens into the valve casing of the low pressure
cylinder, an injector consisting of a cone shaped or inclined orifice around the said
end of the said pipe or passage for injecting live steam therearound and in front
thereof in a conical stream, whether there be used or not in combination with the
said injector a valve, essentially as and for the purpose herein before described with
reference to Figure 2 of the accompanying Drawings.
Third. For condensing the exhaust steam of the engines of steam tramway cars
or analogous engines, the combination with the exhaust pipe or passage of a
surrounding casing or casings (k) and perforations in the exhaust pipe or its
continuation and the means for admitting air to, or forcing air into, the said casing
or casings, and therefrom into the exhaust pipe or passage or its continuation to
condense the exhaust steam, essentially as hereinbefore described with reference
to the accompanying Drawings.
Fourth. The inclined or cone shaped orifice p around the end of the casing k or
around the exit end or nozzle or termination of the exhaust pipe of the low
pressure cylinder (where it enters the condensing tank or receiving vessel) for
injecting air in a conical stream into or in front of the said exhaust pipe termination
or nozzle.
Fifth. The condensing nozzle for the exhaust steam from the low pressure
cylinder, consisting of an air casing and perforated pipe or nozzle for admitting or
injecting air into and around the said pipe or nozzle in combination with the
deflecting cones or funnels q, r, there being a hole w or its equivalent (provided or
not with an air inlet valve) for giving communication between the outside of the
nozzle and inside of the same above the water space of the condenser, essentially
as herein before described and illustrated in Figure 11 of the accompanying
Drawings.
In witness whereof, I, the said Thomas Robertson, junior, have hereunto
set my hand and seal, this Twelfth day of July, in the year of our Lord One
thousand eight hundred and eighty one.
THOMAS ROBERTSON, JUR. (L.S.)