IMPROVEMENTS IN OBTAINING MOTIVE POWER AND IN APPARATUS THEREPOR
Year: 1868

page_text: LETTERS PATENT to Edmund Hunt, of Glasgow, in the County of
Lanark, North Britain, for the Invention of "IMPROVEMENTS IN
OBTAINING MOTIVE POWER AND IN APPARATUS THEREPOR."
Sealed the 20th November 1868, and dated the 25th May 1868.
PROVISIONAL SPECIFICATION left by the said Edmund Hunt at the
Office of the Commissioners of Patents, with his Petition, on the
25th May 1868.
I, EDMUND HUNT, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN OBTAINING MOTIVE POWER AND IN APPARATUS THEREPOR," to be as
follows, that is to say:-
This Invention has for its object to economise fuel in obtaining motive
power by means of steam or other similarly liquefiable vapor, and it
comprises arrangements whereby steam from a low-pressure receiver or
boiler is made to actuate any convenient kind of steam engine, and is then
wholly or in part returned to the low-pressure receiver by means of a

page_text: jet or jets of steam from a high-pressure boiler or receiver. Or a jet or
jets of steam may be made to act in the passage leading from the low-
pressure receiver to the engine either in addition to or instead of the jet
or jets acting on the exhaust steam. The action on the steam on its way
either to or from the engine may be effected by a suitably proportioned
injector of any of the kinds in use for feeding boilers, but it is preferred
to employ an inductor of a new construction placed inside of the
receiver when acting on the exhaust steam, and consisting of a jet piece
comprising two shells shaped like the mouth of a trumpet or otherwise
so as to direct a jet or film of steam in radiating lines in a plane. The
high-pressure steam issues from between the outer edges of the expanded
parts of the two shells being admitted to the space between the shells
(which is otherwise closed) by a pipe or pipes from the high-pressure
boiler. The exhaust passage from the engine is made to communicate
with spaces on both sides of the high-pressure film or jet, one of the
communications being through the centre of the jet piece. The shells
or plates forming the sides of the spaces are conoidal, so that the space
between them and in the central plane of which the high-pressure jet
issues becomes gradually wider as it recedes from the centre. The
object of this construction is to give the particles of steam as much
scope as possible to diverge from each other as they tend to do when
steam of a high-pressure rushes and expands into a space in which there
is a lower pressure, it being expected that the freer such divergent
action is the more effective will be the inductive action on the exhaust
steam from the engine. A similar inductor may be placed in the valve
chest of the engine for the purpose of imparting increased force to the
steam on entering the engine. It will be necessary to withdraw some
steam from either the low-pressure receiver or from the exhaust passage
of the engine, namely a weight equal to that of the steam admitted
from the high-pressure boiler, and as the same quantity has to be fed
into the latter it will be most convenient to condense or liquefy the
necessary quantity, by preference by means of surface condensation,
and to feed it into the high-pressure boiler by means of a pump or
injector. If an injector is used it may possibly be worked by steam
from the low-pressure receiver, in which case that steam must be taken
into account along with the water of condensation. If preferred the
high-pressure boiler may be fed with water from an external source,
the corresponding weight of steam being withdrawn from the engine by
means of a jet condenser, or being allowed to escape into the atmosphere.

page_text: The pressures in the two boilers or receivers may be in various pro-
portions, but it is preferred to have them as different as possible
consistently with practical convenience.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edmund Hunt in the Great Seal Patent Office
on the 25th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
HUNT, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of May, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-first
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Edmund Hunt, Her special licence that I, the
said Edmund Hunt, my executors, administrators, and assigns, or such
others as I, the said Edmund Hunt, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN OBTAINING MOTIVE
POWER AND IN APPARATUS THEREFOR," upon the condition (amongst others)
that I, the said Edmund Hunt, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Edmund Hunt, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and hy
the following statement in writing, reference being had to the accom-
panying Drawings, that is to say :-

page_text: My said Invention has for its object to economise fuel in obtaining
motive power by means of steam or other similarly liquefiable vapor, and
it comprises arrangements whereby steam from a low-pressure recciver
or boiler is made to actuate any convenient kind of steam engine, and
is then wholly or in part returned to the low-pressure receiver by means
of a jet or jets of steam from a high-pressure boiler or receiver. Or a
jet or jets of high-pressure steam may be made to act in the passage
leading from the low-pressure receiver to the engine either in addition
to or instead of the jet or jets acting on the exhaust steam. The action
on the steam on its way either to or from the engine may be effected by
a suitably proportioned inductor similar to any kind of feed injector in
use for supplying water to boilers.
I have hereunto appended a Sheet of explanatory Drawings to be
herein-after referred to, and representing three modifications of inductors
designed for practically carrying out my said Invention, these modifi-
cations being what I at present believe to be the best adapted for that
purpose, and differing from a modification which I formerly preferred and
which is described in the Provisional Specification lodged with my
application for the herein-before in part recited Letters Patent.
In order to maintain the apparatus in continuous action it will
obviously be necessary to feed continuously into the high-pressure boiler
an equivalent for the steam which issues from it to work the inductor or
inductors, and steam must be condensed for this purpose. The con-
densation thus required is most advantageously applied at or near the
point where the high-pressure jet or current acts on the exhaust steam
so as to avail of the well-known action whereby a current of steam has
its velocity increased on approaching a point of condensation, the
intention being to obtain an improved action of the jet through such
increased velocity. When the condensation is applied in this way the
water due to it passes into the low-pressure receiver and is transferred
thence to the high-pressure boiler by a feed pump. The condensation
may be effected in the inductor by a jet or by surface action, and if the
former is used the jet should by preference consist of water obtained
by surface condensation from a portion of the exhaust steam of the
engine.
The inductor shown in longitudinal section in Figure 1 comprises a
body casting 1, formed with a flange 2, whereby it is bolted to the
shell 3 of the low-pressure receiver into which its nozzle 4 projects. The

page_text: exhaust steam from the engine has access to the apparatus by a pipe 5
entered into a stuffing box in the outer end of an inner nozzle 6, which
is screwed into the body 1. The high-pressure steam enters by a
pipe 8 into a space 9 formed in the body 1 so as to surround the
inner nozzle 6, and this space contracts towards the receiver; the inner
end of the inner nozzle 6 is also contracted and closes the space 9 when
screwed inwards. When the apparatus is in action the inner nozzle 6
is screwed outwards so as to allow a thin annular film of high-pressure
steam to issue from the space 9 into the central passage, wherein it
acts on the exhaust steam from the engine and carries it into the
receiver. When a condensing jet of water is used, as herein-before
explained, it may be led in by a small central pipe 10.
In the second modification of inductor, which is shown in longitudinal
section in Figure 2, and in cross section in Figure 3, provision is made
for effecting the condensation by surface. A corrugated cone 11 of thin
sheet metal, such as copper, is inserted between two conical surfaces of
cast iron, and the high-pressure steam which is admitted by the pipe 8 to
an annular space 9 at the base of the cone passes towards the apex along
the insides of the corrugations, whilst cold water is led along their
outsides in a contrary direction. The corrugated copper cone has rings
brazed on its apex and base, and turned to fit seats turned for them in the
body casting 1. The apparatus is in other respects similar to the first
modification excepting that it has a differently shaped nozzle 4 within
the receiver.
The third modification, which is shown in longitudinal section-in
Figure 4, is like the second constructed for applying the condensation
by surface. The passages for the steam are between plain cones 11 of
thin copper, of which cones there may be one or more pairs, two pairs
being adopted in the modification delineated. The cones 11 bear against
corrugated cones of cast iron, the corrugations serving as passages for
cold water which is led in by pipes in such a way as to pass along the
surfaces of the cones in the opposite direction to the convergent steam
currents. The red and blue arrows show the steam and water currents
respectively.
The Drawings represent inductors of a size suitable for a steam engine
of six horses' power nominal, and intended for working with a pressure
of from thirty to forty pounds per square inch in the low-pressure
receiver, and with a pressure of from eighty to one hundred pounds per

page_text: square inch in the high-pressure boiler. The pressures in the two boilers
or receivers may be in various proportions, but I prefer to have them as
different as possible consistently with practical convenience. If preferred
the high-pressure boiler may be fed with water from an external source,
the corresponding weight of steam being withdrawn from the engine
by means of a jet condenser or being allowed to escape into the
atmosphere.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details herein described or delineated, but
that what I believe to be novel and original, and claim as the Invention
secured to me by the herein-before in part recited Letters Patent is, the
working of a motive-power engine with steam or other similarly lique-
fiable vapor from a receiver into which it is returned by means of an
inductor worked by steam or vapor of a higher pressure than that in the
receiver, substantially as herein-before described.
In witness whereof, I, the said Edmund Hunt, have hereunto
set my hand and seal, this Twenty-third day of November,
in the year of our Lord One thousand eight hundred and
sixty-eight.