IMPROVEMENTS IN COMBINED STEAM BOILERS AND STEAM ENGINES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Killingworth William Hedges
at the Office of the Commissioners of Patents, with his Petition,
on the 5th February 1874.
I, KILLINGWORTH WILLIAM HEDGES, of Wootton Lodge, Streatham
Hill, in the County of Surrey, Civil Engineer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN COMBINED STEAM BOILERS
AND STEAM ENGINES," to be as follows:-
:-
The Invention relates, firstly, to that class of vertical combined
steam boiler and steam engine in which the engine is mounted on the
top of the boiler, and in which the furnace is placed in the centre of the
fire-box, and an annular smoke space is left between the furnace and
the sides of the fire-box to permit of the smoke and products of com-
bustion after acting upon the crown of the fire-box to pass downwards
in such annular smoke space, and then underneath the lower edge of the
boiler, whence it either passes direct into the flue or first rises into
another annular smoke chamber around the boiler.

page_text: According to the first part of my Invention instead of forming the
furnace of a plain entire cylinder of fire-clay, as heretofore, I construct
it in two halves, the joint being made in a vertical and horizontal
direction, so that one half overlaps the other at the joint. By this means
I obviate the splitting of the cylinder, which takes place when made
entire. I form a projection on one of the halves, which bears loosely
against the side of the fire-box and forms the communication between
the exterior of the boiler and interior of furnace. A projection is also
formed on the top of the other half, which serves to prevent it being
displaced when stoking, and also acts as a baffler to prevent the products
of combustion passing away in one direction only.
If it is preferable to build up the cylinder in fire-brick in addition to
the above-mentioned projections I form certain of the bricks with Jugs
or projections on their sides; these bear against the sides of the fire-box
and prevent the furnace being displaced by stoking.
The furnace is carried by an annular support fixed to the bottom of
the foundation plate, to which the boiler is rigidly connected; this
annular support also carrying the fire-bars, the interior forming the ash-
pit. Access is obtained to the ash-pit and interior of the furnace by a
suitable opening, which also affords access to the flues for cleaning.
If it be found desirable to generate steam by the combustion of gas
instead of coal I provide the following additions to the furnace :-I
arrange a series of Bunsen's burners in the interior of the fire-clay
furnace, in the bottom of which is fixed a cast-iron or firc-clay plate
pierced with small holes. A current of air is drawn through the plate
by the heat of the gas burner above, thus causing a more powerful
draught and more perfect combustion of gas. The plate also scrves to
prevent the gas becoming ignited in the mixing chamber of the Bunsen
burner.
The Invention consists, secondly, in forming the flange of the cylinder
so that besides forming the foundation of the engine as heretofore it
shall also form the guide for the guide block to work on, so that the
guide can be trued up at the same time as the cylinder is bored.
I also form the under side of the flange of the cylinder with a chipping
strip on it, which is faced, and which makes a joint with a ring rivetted
on to the top of the boiler, a thin sheet of lead being placed in the joint
to obviate the differences of expansion. By this means I am able to

page_text: make a more durable joint than has been done heretofore with india-
rubber.
To enable the slide valve to be readily got at without breaking the
joint between the engine and boiler I make the top of the valve chest
with stuffing box removable.