Improvements in Steam Generators or Boilers.
Year: 1893

page_text: Date of Application, 15th Aug., 1893-Accepted, 16th Sept., 1893
UOMI LEIE DI MUITICAL
Improvements in Steam Generators or Boilers.
I, JOHN PERCY HALL, of Carville, Laurie Park Road, Sydenham, in the
County of Kent, Managing Engineer, do hereby declare the nature of this
nvention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The object of my invention is the construction of steam boilers or generators
suitable for steam launches and for other uses where lightness and rapid generation
of steam are especially required.
I construct a steam generator with two annular water chambers connected
together by water tubes. The lower water chamber is approximately semi-circular
in section and the top of this water chamber constitutes a tube plate into which
water tubes are set at suitable distances apart all round leaving however a space
opposite to the fire door for feeding the fire. The fire is supported upon a grate
which occupies a central position in respect to the lower water chamber. The water
tubes may be ranged in four or other number of concentric circles. The upper
water chamber is of smaller diameter than the lower, its upper part is semi-circular
and its under side consists of a tube plate. The tubes extend from one tube plate
to the other inclining inwards as they rise and the tube plates have a corresponding
conical form.
The upper water chamber is of a size to admit of its serving also as a steam
dome.
The whole is enclosed in a dome shaped fire box supported on the edge of the
lower water space and at the top is the outlet to the chimney to which the products
of combustion pass partly through the central opening in the upper water chamber
and partly around its exterior.
Sometimes to obtain a more rapid circulation I insert a large pipe or pipes
amongst the water tubes, these form upcast passages for the water. Within each
of the large pipes another smaller pipe is fixed to serve as a down cast passage, it
is open at both ends and its upper end has a trumpet or bell shaped mouth to
assist or encourage the flow.
I sometimes make similar steam generators of rectangular form with two straight
water chambers at the top and two others at the bottom. The lower water
chambers lie one on either side of the fire and are connected by the tubes to the
water chambers at the top. The tubes on either side incline inwards as is the case
when the water chambers are of circular or annular form as already described.
The two lower water spaces are also connected by cross pipes and the upper
chambers have branches leading into the main steam pipe. To assist the circulation
I in this case also provide amongst the tubes a large pipe or pipes connecting the
upper and lower water spaces and containing another pipe serving as a down cast
passage.
Sometimes I arrange the water tubes to cross each other in the middle over the
fire, the tubes from the lower water space on the left side meeting the upper water
space on the right side and vice versa. 1 also provide other water tubes not crossing
over the fire; these latter become less highly heated than the tubes crossing the
fire and in them the flow is downward whilst in the former tubes it upwards.
Boilers such as I have described are easy of construction and present a large and
effective area of heating surface, and are conducive to a rapid circulation, relatively
to the size and weight.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings annexed.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of a circular boiler in accordance with my invention.
Figure 2 is a plan of the lower part or base thereof.
Figure 3 is a transverse section and Figure 4 is a longitudinal section of a
rectangular boiler in accordance with my invention.
Figure 5 is a transverse section and Figure 6 is a longitudinal section of another
rectangular boiler in accordance with my invention and in which some of the water
tubes cross each other over the fire.
In Figures and 2 a is the lower water chamber and is the tube plate which
forms the top or cover to this chamber. ccc are water tubes set in the tubė
plate b; they may occupy the whole of its surface excepting a space opposite to
the fire door at d or as the figures indicate space may be left for other circulating
tubes of larger size. e is the fire grate, around it a fire brick ring f is set upon the
plate in order to keep the fire together. g is the upper water chamber and is
the tube plate which forms the bottom of this chamber. The cover g₁ of the
chamber is removable to give access to the ends of the tubes c so that the joints
in the tube plate may be made good. is a coating of fireclay to prevent the parts
above the water line from becoming unduly heated. k is the fire box, its sides may
be of thin sheet iron, double and packed with non conducting material. I is the
entrance to the chimney. m m are large pipes which may be provided to aid the
circulation; they contain within them smaller pipes nn. The heat of the fire
acting on the exterior of the tubes m maintains an upward current in the annular
space between m and n; the pipe n not being exposed to this influence carries a
counter current. The steam connections are made upon the dome or cover g' but
they are not shown in the drawing; the boiler is provided with the usual fittings
which also are not represented.
In Figures 3 and 4 the water chambers are straight in place of circular and are
arranged on either side of the fire; in most other respects the boiler is similar to
that already described and the parts are marked with corresponding letters. The
lower water chambers are connected by a pipe a¹ and the covers g' of the upper
water chambers which serve as steam domes are connected by a steam pipe g³ out
of which branches the pipe g³ which carries off the steam to the engine or otherwise
for use.
In the boiler shown by the Figures 5 and 6 many parts are similar to those
already described and so far they are marked with similar letters but for some of
the tubes c other water tubes c¹ crossing over the fire are substituted; these become
more highly heated than the former and the flow in them is upwards, whilst the
return flow takes place by the lateral tubes c. The lower water chambers a are
provided with end covers and are of sufficiently large dimensions to allow free
access to the ends of the tubes c and e' which are set directly into the sides or walls
of the water chamber. The upper ends of the tubes c and c are accessible by
removing the cover plates gg which close the upper water chambers.
The steam spaces in the upper chambers are connected and the steam after
passing a stop valve is dried by passing through the pipe g' in the upper part of
the fire box. The fire box may be formed in various ways as the several figures
of the drawings indicate.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A steam generator or boiler substantially as described consisting of an upper.
and a lower water chamber of annular form connected by inclined water tubes set
into tube plates which form respectively the top and the bottom of the two water
'chambers.
2. A steam generator or boiler substantially as described consisting of an upper

page_text: and a lower water chamber of annular form connected by inclined water tubes and
having the circulation aided by tubes of comparatively large dimensions set one
within the other.
3. A steam generator or boiler substantially as described consisting of two upper
and two lower rectilinear water chambers connected in pairs by inclined water
tubes and arranged one pair on either side of a fire grate.
4. A steam generator or boiler substantially as described consisting of two upper
and two lower rectilinear water chambers connected in pairs by inclined water
tubes and arranged one pair on either side of a fire grate and having the circulation
aided by tubes of comparatively large dimensions set one within the other.
5. A steam generator or boiler substantially as described consisting of two upper
and two lower water chambers arranged on either side of a fire grate and each
upper water chamber connected to its opposite lower water chamber by inclined
water tubes crossing each other in the space above the fire, other water tubes not
crossing each other connecting the lower with the upper water chambers on each
side of the fire grate.
6. Steam generators or boilers substantially as described and illustrated by the
annexed drawings.
Dated thi 14h 1
CA
1000