HOT AIR ENGINE
Year: 1885

page_text: We, MATTHEW PIERS WATT BOULTON at present of Hotel de Rivoli, Paris in
the Republic of France, Gentleman and EDWARD PERRETT, of N° 8 Victoria
Chambers, Westminster in the County of Middlesex, Engineer, do hereby declaro
the nature of our invention for "HOT AIR ENGINE" to be as follows:-
:―
Our invention relates to a construction of hot air engine of the kind in which
air is forced by a pump through a heater or generator, and the heated air or
products of combustion act as the working fluid..
The object which we have in view is to balance as much as possible the force
required to work the air compressing pump, and to maintain the temperature of
the cylinder in which the hot fluid first acts:
For this purpose we employ in combination three cylinders, the first with its piston
acting as an air compressing pump which forces air into the heater or generator,-
the second or charging cylinder receiving from the heater or generator, hot air,
which with little or no expansion propels the piston of the second cylinder,—and
the third or expansion cylinder receiving from the second the hot air discharged
which expands propelling the piston of the third cylinder. These three cylinders
may he placed in line with one another having their pistons rigidly connected
together and linked to a single crank. The first and second cylinders being about
equal, the work performed by the hot air in the second approximately balances the
pumping work performed in the first; and the third cylinder, being larger, the hot
air expands therein performing work. This latter or expansion cylinder, instead
of being in line with the first and second cylinders, may be placed at their side,
having its piston linked to a crank so set on the shaft relatively to the crank to
which the pistons of the first and second cylinders are linked, that, while the
piston of the second makes its instroke discharging hot air, the piston of the third
makes its outstroke receiving behind it the hot air so discharged. The valves for
governing the passage of the hot air to and from the second and third cylinders
are in the form of pistons balanced by pressure on both their sides, so that
lubricant can pass freely over the rubbing surfaces..
O
1
1
100k
ABEL & IMRAY,
_ Agents for the Applicants,
28, Southampton Buildings,
London, W.C.

page_text: We, MATTHEW PIERS WATT BOULTON at present of Hotel de Rivoli, Paris, in
the Republic of France Gentleman, and EDWARD PERRETT of N° 8 Victoria
Chambers, Westminster in the County of Middlesex, Engineer, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Our invention relates to a construction of hot air engine of the kind in which
air is forced by a pump .through a heater or generator and the heated air or
products of combustion act as the working fluid.
The objects which we have in view are to balance as much as possible or
desirable the force required to work the air compressing pump, and to maintain
the temperature of the cylinder in which the hot fluid first acts.
For this purpose we employ in combination three cylinders the first with its
piston acting as an air compressing pump which forces air into the heater or
generator, the second or charging cylinder receiving from the heater or generator,
hot air, which, working with late cut-off or little expansion, propels the piston of
the second cylinder, and the third or expansion cylinder, receiving from the second
the hot air discharged from it, which expands propelling the piston of the third
cylinder. These three cylinders may be placed in line with one another having
their pistons rigidly connected and linked to a single crank. The first and second
cylinders being about equal in diameter, the pumping resistance in the first cylinder
never greatly exceeds the driving power in the second, and the third cylinder,
This latter or
being larger, the hot air expands therein performing work.
expansion cylinder, instead of being in line with the first and second cylinders
may be placed at their side, having its piston linked to a crank so set on the shaft
relatively to the crank to which the pistons of the first and second cylinders are
linked, that while the piston of the second makes its instroke discharging bot air,
the piston of the third makes its outstroke receiving behind it the hot air so
discharged. The valves for governing the passage of the hot air to and from the
second and third cylinders are in the form of pistons balanced by pressure on both
their sides, so that lubricant can pass freely over the rubbing surfaces.
Fig. 1 is a vertical section shewing an arrangement of hot air engine according
to our invention with its three cylinders in line with one another, Fig. 2 shews a
similar arrangement of engine somewhat modified; Figs. 3 and 4 shew an arrange-
ment in which the shield on the hot side of the expansion cylinder is dispensed
with; Fig. 5 shews an arrangement in which the third cylinder is situated at the
side of the others and has its piston connected to a crank opposite to that to
which the pistons of the first and second cylinders are connected.
Fig. 6 is a vertical section shewing to an enlarged scale one of the valves tha
govern the air passages to and from the working cylinders. In the various figure
similar reference letters are employed as far as possible to indicate corresponding
parts.
A is the first cylinder or pump provided with suction and discharge valves
The air compressed by it passes by a to the heater or generator. B is the second
cylinder which is fitted with a shielded piston rigidly connected to the piston o

page_text: the pump A. C is the third cylinder. In the arrangement shewn in Figs. 1, 2, 3
and 4, the piston of C is rigidly connected to those of A and B and is linked by
side rods or a connecting rod to two cranks as in Fig. 1 or to a single crank, as in
Figs. 2, 3 and 4, on the fly-wheel shaft D. In the arrangement shewn in Fig. 5
the pistons of A and B are linked to one crank, and the piston of C is linked to an
opposite crank on the shaft D.
There are three valve boxes V1 V2 V3 each constructed like V. Fig. 6, fitted with
a piston valve which is subjected to equal pressure above and below, a pipe or
passage from the space above the piston communicating with the space below it,
as shewn for V and V3 in Fig. 5, or, as shewn for V₁ Fig. 5 with a pipe or space
containing fluid at the same pressure as that which is below the valve piston.
The valves are worked by eccentrics or cams on the shaft D. When V₁ is opened,
heated fluid from the heater enters the cylinder B and urges its piston outwards,
balancing or approximately balancing the pumping resistance acting inwards on
the piston of A. As the pistons of A and approach the end of this stroke the
valve V is closed. Then, on the valve V2 being opened, these pistons make the
return stroke, the hot fluid that had worked in B passing into C and expanding
therein as it propels the piston of C. When this piston reaches the end of its
stroke the valve V' is closed and V³ is opened, and V¹ being again opened, another
stroke is effected, the piston of C expelling the expanded fluid by the valve Vs.
The cylinder B may be heated and its heat maintained by a fire F below B as
shewn in Fig. 5, and the hot products of combustion from this fire may be led
through a space G under C so as to impart heat to that cylinder.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is
1. The construction of hot air engine, substantially as described with reference
to Figs. 1, 2, 3 and 4, with the pistons of its three cylinders rigidly connected
together, to operate as described.
2. The modified construction of hot air engine, substantially as described with
reference to Fig. 5 with the pistons of its first and second cylinders rigidly
connected together and linked to one crank, and the piston of its third cylinder
linked to an opposite crank, to operate as described.
3. In a valve box for an engine worked by hot fluid, balancing the pressure on
both sides of a piston valve, substantially as and for the purpose herein set forth.
Dated this 11th day of November 100K
ABEL & IMRAY,
Agents for the Applicants,
28, Southampton Buildings,
London, W.C.