IMPROVEMENTS IN OBTAINING MOTIVE POWER BY MEANS OF AIR AND STEAM. AND IN APPARATUS EMPLOYED THEREIN
Year: 1868

page_text: LETTERS PATENT to George Warsop, of 17, Bromley Place, Nottingham,.
for the Invention of "IMPROVEMENTS IN OBTAINING MOTIVE POWER BY
MEANS OF AIR AND STEAM. AND IN APPARATUS EMPLOYED THEREIN."
Sealed the 17th November 1868, and dated the 8th September 1868..
PROVISIONAL SPECIFICATION left by the said George Warsop at the
Office of the Commissioners of Patents,, with his Petition, on the
8th September 1868.
I, GEORGE WARSOP, of 17, Bromley Place, Nottingham, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN OBTAINING
MOTIVE POWER BY MEANS OF AIR AND STEAK, AND IN APPARATUS EMPLOYED
THEREIN," to be as follows:-
This Invention has for its object improvements in obtaining motive.
power by means of air and steam and in apparatus employed therein.
The machinery which I employ consists of a steam boiler and an engine,:
which may be similar to those now. in use, and the engine works an air:

page_text: pump or pumps, drawing in cold air and forcing it through a coil of pipes
or other suitable chamber heated by the furnace, and from this heated
coil or chamber the air passes into the boiler and is caused to rise in a
finely divided state through the water therein contained. The air and
steam together pass from the boiler to work the engine. I prefer to
open and close the valves of the air pump at suitable times by means of
cams, as the pumps then work more efficiently than when the valves are
self-acting. The heating of the air after it leaves the pump or pumps
may be effected by passing it through hollow fire-bars, or apparatus such
as is now employed for superheating steam may be used for heating the
air. The air is caused to be finely divided as it passes through the water
by means of partitions of wire gauze or other openwork or perforated
material.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Warsop in the Great Seal Patent Office
on the 8th March 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
WARSOP, of 17, Bromley Place, Nottingham, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of September, in the
year of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said George Warsop, Her special licence
that I, the said George Warsop, my executors, administrators, and
assigns, or such others as I, the said George Warsop, my executors,
adininistrators, and assigns, should at any time agree with, and no
others, from time to time, and at all times. thercafter 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 BY MEANS OF AIR AND STEAM, AND IN APPARATUS
EMPLOYED THEREIN," upon the condition (amongst others) that I, the
said George Warsop, my executors or administrators, by an instrument
in writing under my; or their; or one of their hands and seals, should

page_text: particularly describe and ascertain the nature of the said Invention,
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 George Warsop, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its object improvements in obtaining motive.
power by means of air and steam, and in apparatus employed therein.
The machinery which I employ consists of a steam boiler and an
engine, which may be similar to those now in use, and the engine works
an air pump or pumps drawing in cold air and forcing it through a coil
of pipes or other suitable chamber heated by the furnace, and from this
heated coil or chamber the air passes into the boiler and is caused to rise'
in a finely divided state through the water therein contained. The air
and steam together pass from the boiler to work the engine. The
heating of the air after it leaves the pump or pumps may be effected by
passing it through hollow fire-bars, or apparatus such as is now employed
for superheating steam may be used for heating the air. The air is
caused to be finely divided as it passes through the water by means of
partitions of wire gauze or other openwork or perforated material.
In order that my said Invention may be most fully understood I will.
proceed to describe the manner in which I prefer to carry the same into
effect. I take an ordinary high-pressure steam engine, but of larger size.
than would if it were worked in the ordinary manner be required for.
the office which it has to perform, and I apply to this engine an air.
pump or air pumps, by preference of such capacity that for each stroke
they will together yield a measure of compressed air of the boiler
pressure of the engine equal to about one-half to the measure of
mixed air and steam which is expended at each stroke of the engine. In
this case more than half of the power obtained in the working cylinder.
will be expended again in compressing the air, and the area of the.
working cylinder must be proportionally large. These proportions,
however, may be varied, and it is advantageous frequently so to con..
struct the engine that they may be varied from time to time as may be,

page_text: required by altering the effective length of stroke of the air pumps, then
by reducing the quantity of air a greater power may be obtained from
the engine, but less economically. The air pumps may conveniently be
worked by eccentrics or cranks on the main shaft of the engine and
may be of ordinary construction. I prefer that the valves of the air
pump should be ordinary conical valves, and the valves should be of
sufficient area to give free passage to the compressed air with but a short
lift, for it is important to the proper working of the engine that the valve
should close again rapidly as soon as the stroke of the pump is completed.
The inlet valve may in each case be a spring pallet working over a passage
in the piston, which is of a sufficient area freely to admit the air, and
the pallet spring is not sufficiently strong to oppose to it any con-
siderable resistance, but the spring is yet sufficient when the entry of
the air ceases to cause the immediate return of the pallet, so that it
may cover closely the mouth of the inlet passage at the time that the
delivery stroke of the air pump commences.
The boiler may be of any good construction, so long as it has a
considerable water capacity and depth it need not be larger than in
the ordinary proportion to the effective power of the engine. In the
flue, or otherwise in connection with it, an air-heating apparatus is
provided; such a heating apparatus may be used as has heretofore
been employed for superlicating steam; it should be capable of raising
the compressed air from the air pumps to a temperature at least equal
to and advantageously it may somewhat exceed the saturated steam
temperature corresponding with the pressure at which it is intended to
work. The engine may be worked at any high pressure, 50 lbs. per
square inch above the atmospheric pressure is a suitable and con-
venient pressure, but greater economy may be obtained by the use of
a higher pressure. Coils of wrought-iron pipes in the boiler furnace
and flue form a convenient air-heating apparatus, and in small engines
a part of the coil may advantageously form the fire-bars of the boiler.
The compressed air after passing through the heating apparatus is
admitted into the boiler at the lowest part of the water spaco through
a valve, which is employed to prevent the escape of water from the
boiler into the heating apparatus; this valve also it is found convenient
to make like the exit valves of the air pumps. The heated air as it
rises up through the water in the boiler is caused to be divided into

page_text: as many and minute streams as possible by means of suitable partitions.
I have found for this purpose the use of wire gauze to be convenient,
and I arrange it as observation may in each case suggest, wherever
the air rises up in quantity there I oppose to it a number of thick-
nesses of wire gauze sufficient to reduce the flow, and in this way I
distribute the air and cause it to ascend equally, or nearly so in every
part of the boiler. It is important that the distribution of the air
amongst the water in the boiler should be attended to, for in this
engine one main purpose which the water in the boiler performs is to
regulate the heat of the air, absorbing from it any excess of heat it
may have acquired before it enters the boiler, or supplying heat to it
as the case may require. The air and steam together pass from the
boiler to the engine, and are admitted to the working cylinder as when
using unmixed steam, but in this case the power of the engine will
result for the greatest part or in great part from the expansion of the
air by heat between the time when it is taken in by the air pumps and
the time when it is passed together with the steam into the working
cylinder. The degree to which the steam and air are expanded in the
working cylinder will, as heretofore, depend on the conditions of the
application in each particular case, but I would remark that with this
engine expansion may advantageously be carried to a considerable
extent without there being any necessity to steam jacket the cylinder,
the cylinder being simply clothed with felt in the usual way. When
the expansion is to be carried far it is desirable that the air should.
enter the boiler at a temperature considerably above that of the water
which the boiler contains, and then the mixed steam and air will pass
off from the boiler at a heat a good many degrees above that of
saturated steam at a corresponding pressure, or in fact .the steam which
the mixture contains will be to a small extent superheated, and so is
in a state to be very advantageously worked expansively. The exhaust
steam and air from the engine I cause to pass through a tubular
casing; it is clothed with felt to prevent loss of heat, and the pipe
which receives the compressed air immediately it comes from the air
pumps is made to pass through the interior of the casing from end to
end, entering it near where the exhaust air and steam escape, and
leaving it to pass to the air heater near where the exhaust steam and
air enters from the cylinder. The casing should be made sufficiently
long to avoid any great loss of heat with the exhaust air and steam.

page_text: I would remark that by means of these arrangements the theoretical
economy of an air engine, that is to say, that of an engine worked by
the expansion of air by heat, are to a considerable extent practically
realized, whilst many of the difficulties attendant on the use of air
engines are avoided. The. steam boiler affords a ready means of re-
gulating the temperature of the air, as already stated, and also of
obtaining the requisite pressure for starting it; ensures that the
temperature of the mixed air and steam passing to the cylinder shall
never rise so high as to injure the lubricants there employed, and
the steam itself as in an ordinary steam engine furnishes sufficient
moisture to prevent the rubbing surfaces from being absolutely dry.
The manner adopted for heating the air also it may be observed is
such as to preclude the possibility of the air carrying with it dust
and cutting particles into the working cylinder. The engine may where
the nature of the work renders it desirable have more than one working
cylinder, and again it is not essential to my Invention that the engine
should be of the cylinder construction; it may be a rotary engine,
although in all cases I prefer a cylinder. engine.
The Invention is applicable to locomotive as well as to stationary
and portable engines, and in its application to locomotive engines a
considerable advantage is that the quantity of water which is required
for its supply is much smaller than is required by an ordinary steam
engine of the same power. In the case of locomotives the air may
first be heated by passing through a coil of pipes in the smoke box
before passing into the heating apparatus in the furnace, and so utilize
the waste heat in the smoke box. In some cases, especially in largo
engines, a separate fire may be employed for the air heater. In other
cases the air may be forced at once into the boiler without being
previously heated, and so be made to take up its heat entirely from
the water in the boiler. I believe, however, that it is always morc
advantageous to employ an air heater to heat the air previous to its
admission to the boiler.
What I claim as my Invention is, the combining air-forcing apparatus
with an engine suitable to be worked by steam or other fluid, such
air-forcing apparatus taking in air in a cold or comparatively cold or

page_text: state and in combination with steam generated in the boiler it passes
to the engine which it actuates, as herein described.
In witness whereof, I, the said George Warsop, have hereunto set
my hand and seal, this Fourth day of March, in the year of our
Lord One thousand eight hundred and sixty-ninc.