IMPROVEMENTS IN OBTAINING MOTIVE POWER BY AIB
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISHAN
BAGGS, of Great Percy Street, Claremont Square, in the County of Middlesex,
Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-sixth day of June, in the ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Isham Baggs, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Isham Baggs, my
exors, admors, and assigns, or such others as I, the said Isham Baggs, my
exors, adiñiors, or assigns, should at any time agree with, and no others,
from time to time, and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick upon Tweed, my Invention of
"IMPROVEMENTS IN OBTAINING MOTIVE POWER BY AIB;" in which said Letters
Patent is contained a proviso, that I, the said Isham Baggs, shall cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be inrolled in Her said Majesty's High Court
of Chancery within six calendar months next and immediately after the
date of of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully aud at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Isham Baggs, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thereon
(that is to say):-
The nature of my said Invention of "Improvements in Obtaining Motive
Power by A consists in applying the physical properties of atmospheric
air to the movement of machinery, in manner following:-
First, I cause a vessel heated by fire, and containing condensed air, to
communicate with a working cylinder at proper intervals of time, so as to
actuate its piston upwards and downwards alternately, through the movement
of suitable valves, as in the steam engine; and I supply the loss of condensed
air, which is thus occasioned, by pumping into the heated vessel fresh supplies
of cold air from the atmosphere through the action of the engine.
Secondly, I cause the hot air, after it; has done its duty in the cylinder, to
pass into the fire, so as to increase the intensity of combustion, and economize
fuel: It will this be seón that. I.. do not depend for the action of my
machinery upon any condensing principle or application where refrigeration is
employed in producing a partial vacuum, but that, I rest upon expansion
alone, as in the high-pressure steam engine.:
+1
In oriler, however, that my Invention may be fully understood, I have
attached to tliese Presents a Sheet pf Drawings, which I will now par-
ticularly explain. In the different sections similar: letters of, reference refer
to similar parts. A represents .the: brickwork supporting the engine; B,
the furnace; C, the ash-pit; D, the flue,. the course of which is indicated
by the arrows; E, the damper, which is made in the form of a valve, and.
placed a little way up the chimney; F, the eduction pipe; G, the air.
pipe for supplying the engine; H, the bed plate; I, the pillars; J, the
entablature; Ky-the crank shaft; L, the excentric for working the induc
tion-valves of the cylinder; M, the excentric for the eduction valves of the
same; N, N, excentric rods; O, fly wheel; P, working cylinder and piston;
Q, piston rod; R, pump and pump piston; S, induction left valves for
admitting atmospheric air to the. pump R; T, eduction valves of similar
construction, for allowing the contents of the pump. to be discharged into the:
generator or vessel wherein the expansion of the condensed air is effected.
by the heat of the furnace. This latter. vessel is, marked U.; it, is built of
hammered irön, strong and air-tight, and, the. cylinder P is fixed within it;

page_text: V is the pump rod; W, the connecting rod for the pump; and X, the con-
necting rod for the cylinder; at Y is the situation of the valve for stopping the
engine; it is here fixed in the pipe G; by closing it the supply of atmospheric
air to the pump is cut off, and the motion of the engine is. arrested; Z is a
plate of iron or other material placed in front of the generator U, in order to
preserve it from the direct action of the fire; d, d, are the slide valves for the
working cylinder. I start the engine in manner following:-The fire being
lighted, I first fill the generator U with condensed air, by means of condensing
pump,, reservoir, or other convenient means, till the guage indicates a pressure
of four atmospheres. The condensing pump is merely. required for starting
the engine, and is, worked. by manual labour or other independent power.
The fly wheel O being now turned in the direction of the arrows, the slide
valves d, d, are thrown into motion, and pressure is thus admitted from the
generator to one side of the piston,, while the exhaust valve in. connection with
the opposite side is thrown open. The machinery is now actuated by the,
force within itself, and its various parts are moved in a manner analagous to
the corresponding portions of an ordinary steam engine. At every stroke
of the piston a certain portion of hot air is of course withdrawn from the
generator, but this loss is compensated for by the simultaneous action of the
condensing pump R, which forces into the generator a fresh supply of cold
air at every stroke. It will be seen, that, setting aside the slight leakage that
inay exist in the parts of the engine, the weight of air pumped into the
generator, and the weight expelled by the working of the hot cylinder P, are
precisely the same. The volume of course is not different, being in either
case proportioned nearly to the relative capacity of the two cylinders. It will
be seen also that the pump valves T do not open before the pressure of air in.
the pump exceeds that in the generator, that is to say, when the
pump piston
has finished about three-fourths of its stroke, it follows that only one-fourth of
the actual volume of the pump is thrown into the generator at the standard
pressure (four atmospheres), the previous part of the stroke being employed
in gradually reaching that pressure. To compensate for this, the hot air is cut
off at one-fourth of the stroke in the working cylinder, the remaining portion
of the stroke being effected by expansion. If both pistons commenced and
terminated their, stroke at the same time, the power would be greatest when
the resistance was least, and vice versa. To compensate for this, the cranks
are placed at an angle of about one hundred and forty degrees, so that, leverage
and pressure combined, the power and resistance are made to bear a more
regular proportion to each other in traversing the entire circle. It is neces-

page_text: sary, however, with this arrangement, and with a single working cylinder, that
the motion of rotation should be in the direction of the arrows. The hot air
from the exhaust pipe, instead of being at once thrown into the atmosphere, is
made to pass by the pipe into the fire, so as to economise heat and fuel.
Having now explained the nature of my said Invention, and the manner in
which the same is to be performed, I would wish it to be understood that I
do not claim the production of power by the rarification of air, nor the use of
condensed air for this purpose; but what I claim is,―
First, the constant induction of cold air from the atmosphere, not for the
purpose of being burnt in a close chamber, and producing direct power by the
expansion which it undergoes in combustion, but for the purpose of its being
expanded in a close vessel, exposed on the outside to a fire or other source
of heat.
Secondly, I claim the combination of two or more cylinders in such a
manner as to effect a regular and constant condensation and liberation of air
in the manner described.
And, thirdly, I claim the method of economising fuel in the working of air
engines, by injecting the hot air from the exhaust valves through a pipe or
other means into the fire.
In witness whereof, I, the said Isham Baggs, have hereunto set my
hand and seal, this Twenty-sixth day of December, in the year of our
Lord One thousand eight hundred and forty-five.