Year: 1897

page_text: I, JAMES REGINALD CHURCHILL of Hathersage in the County of Derbyshire,
Engineer, do hereby declare the nature of this invention to be as follows:-
My Invention has for its object the production of a simple, cheap and reliable
steam generator suitable more especially for road vehicles driven by steam. The
generator constructed according to my Invention, need have no more than two
parts as regards the steam or water containing portion of it. It consists of two
jointless tubes or hollow cylinders (hereinafter called tubes) one placed inside the
other, the two said tubes being joined together in a steamtight manner at suitable
places, by rivetting, welding or other means.
The steam and water space (hereinafter called the water space) is between the
outside of the inner tube and the inside of the outer tube.
A Feed Inlet and steam outlet are provided, preferably on the outer tube.
In one class of generator constructed according to this invention, I use two
tubes, one of which tightly fits inside the other; I form the steam space by
depressing, corrugating or removing a certain portion or certain portions of the
metal of which the tube or tubes is or are composed; and I make or leave provision
at suitable places for the two tubes to be so joined together that no steam or
water can leak out from the water space which is contained between the two said
tubes.
In another class, I use two tubes, preferably concentrically placed, of which
the outer diameter of one is less than the inner diameter of the other, and I modify
the tube or tubes in such a way that the modified portions of the same form the
provision for the joining of the two tubes together in a steam tight manner.
There also, the water space is contained between the two tubes.
In some cases I corrugate either or both of the tubes used in this class.
In one form of this generator, I place the fire in the inner tube or in an
independent cylinder or equivalent, which closely fits the said inner tube thus
supporting it against the pressure in the water space and protecting it from
the direct action of the fire the heat from which, it, nevertheless, readily
transmits to the inner tube.
The Heat of the fire thus passes through the inner tube and generates steam in
the water space enclosed between the tubes.
This Independent Cylinder can be readily replaced and thus forms a renewable
firebox adding much to the durability of the generator.
I use grate bars, or an equivalent, for air supply, cleaning, &c., and, where the
generator is fired from the top I place the chimney in such a way as not to
interfere with the accommodation for supplying fuel to the fire.
Or, I attach this combination of two tubes, in any well known manner, to any
convenient form of firebox-the flames and gases, proceeding from which, can reach
to and pass through the inner tube (or the independent cylinder or equivalent

page_text: therein) thus producing an effect almost identical to that obtained by a fire in the
inner tube (or independent cylinder or equivalent).
The water to be used in this generator could be passed, with advantage, through
a heated copper coil, pipe or equivalent; in order that any deposit would surely
take place in the said coil pipe or equivalent and not in the generator proper.
This coil, pipe or equivalent could readily be renewed at small cost.
Dated this 6th day of January 1897
I, JAMES REGINALD CHURCHILL of Hathersage in the County of Derby 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:-
In pursuance of my application, with a Provisional Specification, for a Patent
for "A Steam Generator"; I now describe it with reference to the accompanying
drawings.
At Fig. I I show, in sectional elevation, a steam generator constructed according
to this Invention. It comprises an outer tube 1 and an inner tube 2, which
contains the firebox 3 having grate bars 4. The inlet for fuel is shown at 5 and
the exit for the products of combustion at 6. At 7 and 8 are shown the water
inlet and steam outlet. The tubes 1 and 2 are preferably of welded steel and
the ends are modified as shown, to form provision for jointing by means of the
.-rivets 9. The steam and water space (hereinafter called the steam space) 10 is
. between the tubes 1 and 2.
The corrugations 11 provide against the stresses due to unequal expansion of
the two tubes.
...The firebox 3 is preferably of cast Iron-for cheapness sake-and tightly fits
the inner tube supporting it against the steam pressure and protecting it from
the direct action of the fire, yet readily transmitting the heat thereof to the
said inner tube and thence to the water and steam.
Fig. II shows a section on A. B. Fig. I.
.
Figs. III V and VII show sectional elevations of sets of two tubes which are
alternative to the set of tubes shown at Fig. 1.
Fig. IV shows a section on C D Fig. III.
Fig. VI shows a section on E F Fig. V.
Fig. VIII shows a plan of Fig. VII.
The joints between the two tubes of a set are formed by rivetting or other
suitable means.
Figs. V and VI show two tightly fitting tubes the outer one having annular
corrugations 11 connected by depressions 12. There might be a spiral corrugation
instead of the connected annular corrugations here shown. Figs. VII and VIII
show two tightly fitting tubes-the outer one having its middle portion depressed
or bulged out to provide the steam space 10.
The inner tube of the set might, with advantage, be sometimes made of malleable
Cast Iron or Cast Steel and of such a thickness that the firebox 3 would be
needless.
In any case in which the firebox 3 is dispensed with, the gratebars and chimney
portion can be attached to the tubes themselves.

page_text: The usual accessories for cleaning out, attachment of gauge-glasses and so forth
are added as required.
For ordinary purposes Coke is the best fuel for this generator.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
(1) The steam genrator comprising two modified tube portions and internal
firebox substantially as described with reference to and shown at Figs I to VIII
of the accompanying drawings.
(2) In a steam generator, the combinations of inner and outer tubes modified
substantially as shown at and described with reference to the accompanying
drawings.
JAMES R. CHURCHILL.