IMPROVEMENTS IN THE CONSTRUCTION OF MACHINERY OR APPARATUS FOR OBTAINING MOTIVE POWER
Year: 1861

page_text: LETTERS PATENT to John Gjers, of Middlesbro'-on-Tees, County of York,
for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF MACHINERY OR
APPARATUS FOR OBTAINING MOTIVE POWER."
Sealed the 5th September 1861, and dated the 19th April 1861.
PROVISIONAL SPECIFICATION left by the said John Gjers at the Office
of the Commissioners of Patents, with his Petition, on the 19th April
1861.
JOHN GJERS, of Middlesbro'-on-Tees, County of York, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF
MACHINERY OR APPARATUS FOR OBTAINING MOTIVE POWER," to be as follows:-
This Invention relates to a peculiar construction, arrangement, and com-
bination of machinery or apparatus for obtaining motive power from air, elastic
gases, or superheated steam, and consists in the application and use of a
cylinder provided with a working piston, and in direct and permanent com-
munication at each end with an air vessel or generator, the interior of the two

page_text: air vessels being perfectly separate and distinct from each other and closed to
the atmosphere. In each of these air vessels there is provided a group of
small copper or other metallic tubes fitted into suitable tube plates, which
tubes by being alternately heated and cooled impart heat to or extract the
heat from the air which is contained in the air vessel, and which surrounds
the tubes on all sides. Between the two vessels is a fire-place, from which
two flues branch off, one to the right and the other to the left below the
two air vessels respectively, and leading to the interior of the tubes through
which the direct draught of hot air and gases from the furnace passes
alternately. I prefer, however, that the tubes should form the air vessel, in
which case the hot gases from the furnace pass up in the spaces surrounding
the tubes, the upper ends of the tubes in these air vessels open into similar
flues above, leading to one common chimney placed midway between the two
vessels, and provided with a reversible damper valve, which is so arranged as
to establish a direct communication to the chimney from each air vessel
alternately, the requisite working of the damper valve being effected by a
tappet motion or a quick action cam or otherwise. Whilst the damper valve
allows the hot air and gases from the furnace to pass through the tubes in one
air vessel direct to the chimney, it at the same time allows cold or fresh air
from the atmosphere to enter by a nozzle and pass down the tubes of the
other air vessel, which cold air takes up a portion of the heat from the tubes,
causing the air enclosed in this vessel, and which is in communication with one
end of the cylinder, to contract, whilst the air in the other air vessel is being
simultaneously expanded by the passage through its tubes of the hot air and
gases from the furnace on its way to the chimney. The difference in the
pressure thus obtained on the opposite sides of the piston forces the piston
along its cylinder towards the cold end, but before arriving at this point the
damper valve is reversed, and the hot air and gases from the furnace are
consequently directed through the previously cool air vessel, whilst cold fresh
air is passing down the tubes of the hot air vessel, thus expanding the
previous cold air and contracting the expanded air, whereby the piston is
forced back again to the opposite end of its cylinder, when the same operation
being repeated the motion becomes continuous.
It will thus be seen that the essential feature of this Invention is the
peculiar means for alternately heating and cooling the same body of air on
opposite sides of the piston, namely, the directing of a hot and cold current of
air alternately through each of the air vessels by the aid of the simple draught
alone of the chimney (which might be aided by a fan blower, if required,) and

page_text: a reversible damper valve. In case of breakage occurring a small air pump
may be employed for supplying the loss from either vessel, and for the purpose
of maintaining any desired pressure, so that there will always be sufficient air
in either vessel to force the piston along the cylinder when expanded, the air
5 being worked over and over again, and being heated and cooled at each double
stroke of the piston.