AN IMPROVED METHOD OF CONSTRUCTING BOILERS FOR STEAM ENGINES
Year: 1827

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
FRASER, of ounsditch, in the City of London, Engineer, send greeting.
WHEREAS II is present Majesty King George the Fourth, in and by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eleventh day of January last, for Himself, is heirs and successors,
did give and grant unto me, the said James Fraser, His special licence, full
power, sole privilege and authority, that I, the said James Fraser, my
executors, administrators, and assigns, and every of them, by myself and
themselves, or by my and their deputy or deputies, servants or agents, or such
others as I, the said James Fraser, my executors, administrators, or assigns
should at any time agree with, and no others, from time to time and at all
times thereafter, during the term of years therein expressed, should and law-
fully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick upon Tweed, my Invention of "AN IMPROVED METHOD OF
CONSTRUCTING BOILERS FOR STEAM ENGINES;" in which said Letters Patent there
is contained a proviso obliging me, the said James Fraser, by an instrument in
writing under my hand and seal, particularly to describe and ascertain the
nature of my said Invention, and in what manner the same is to be per-
formed, and to cause the same to be inrolled in Ilis Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said recited Letters Patent, as in and by the same, reference being there-
unto had, will more fully appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said Jame
Fraser, do hereby proceed to describe the nature of my said Invention, th
principal feature of which is to surround a steam boiler or boilers altogethe
or in part with a hollow case to contain water, which case should have a
internal space of the width of three inches or more, in proportion to the siz
of the boiler. The line of water inside the main boiler to be line of water in
the case; sufficient room is to be left between the said case and the said boile
or boilers for heat to pass between them. By this arrangement the whole hea
of the fires which issue from the flues in the interior of the boiler or boilers
instead of passing direct into the shaft, as at present, is brought to act on the
external surface of the boiler, without injuring the timbers of the vessel, ship,
or boat, as will appear by the following description:-Place three flues in the
interior of a boiler, two of which are for fires, and these fires are to be made
so near the sides of the boiler as just to admit of space for cleaning; these
flues proceed through the interior of the boiler from front to back or nearly so,
as the maker may incline; in either case the flame and heat is compelled to
descend under the bottom of the boiler, which is to be curved upwards like a
waggon boiler bottom to make room for the flue between the case and the said
boiler. It is understood that the case is below the boiler bottom as well as at
the sides and end. This boiler, with its bottom curved upwards, is to be made
to rest with its leg on the case, to cut off all communications between the
external sides and bottom flues, so that-the descending heat from the internal
flues comes forward under the boiler nearly to the front under the fire-places,
at which place a part of the boiler is rounded off, or the leg cut at each side,
and a gore made to form a lateral flue to allow the flame and heat to pass from
the bottom to the sides, or, in other words, to pass to the flues between the case
and the sides of the boiler; the flues then proceed to the back of the boiler by
the sides, and these side flues are again bounded by the case, and both flues
are thereby diverted at the back into the third or centre flue in the interior
of the boiler, and again return nearly to the front through that flue, and then
ascend into the shaft for the purpose of draught. When the fires are first lit,
a small fire is to be made in the front of the third or last flue; to effect that
end, the bottom and sides of the boiler or boilers are to be curved inwards, like
the common waggon boiler, for the express purpose of giving room for the flues,
both at sides and at bottom; this lessens the water in the boiler, and the case 3
is also more compact. There is such variety in the method of constructing
Aues that no claim is attempted to be made for any, though there is considerable
novelty in making the side flues re-enter the boiler by the centre fluc. In
and engines the flues may be made to pass under the case as well as under

page_text: the boiler, and thus occasion much additional surface of flue, and consequently
power, and a saving of fuel. Any mechanic accustomed to make steam boilers
will easily conceive the necessary stoppage or check where the internal flues
disgorge on the external surface of the boiler, whether these flues descend
under the bottom to pass to the front where the lateral flues are, or whether
the internal flues are brought to act first on the external sides of the boiler, and
made to pass by the sides forward to the lateral flues and back under the
bottom, for without this stoppage the whole contents of the internal flues would
at once pass into the centre flue, if not compelled by the check to press to the
lateral flues placed nearly under the main fires; but as none of these can sweep
the external surface of the boiler without the assistance of the case to shield
the ship from fire, it is not necessary to describe numerous other arrangements,
nor is it requisite to point out the secondary uses of the case, such as heating
water prior to entering the main boiler, or the uses for which the steam of the
said case could be appropriated. Every engineer is capable of appreciating
these matters, nor will he forget that if a boiler were to be the entire extent of
the engine room, and be about three feet square, with a flue in the middle,
sufficient room would be thus left for the engines in the centre, whilst one third
more surface of heat could be procured, and this again doubled by the assist-
ance of the case; it is evident also that the steam of the main boiler will force
the salt out of the case as easily as out of the main boiler. To prevent the swag
of water in the case, a partition in the middle will be of great use, and it can
be so contrived as to join the said case in two separate parts at the said partition,
and thus facilitating its entrance on board of ship, when there fitted to the
boiler. I therefore proceed to declare that my Invention consists of a case to
contain water being applied to surround the external surface of boilers, alto-
gether if required, or in part, leaving room between for flues for the purpose of
bringing heat at a high temperature to act on the external surfaces of marine
boilers without endangering the ship timbers, thus economising fuel by an
immense enlargement of the surface of flue, and preventing the premature
escape of heat into the funnel or shaft; the said case ought to have an internal
space of the width of three inches, and should be fitted up to the line of water
in the inside of the internal boiler, leaving space above that for the steam;
but although I have specified three inches as the width of the internal space
of the case, less might answer; three inches, however, seem to me to be ample
width for ordinary purpose of security and for cleaning out. Room is to be
left in the case above the said line of water, both at the sides and the end, so
that the steam of the case may be used for any required purpose. Should
bigh pressure engines prevail at sea, the case surrounding the entire boiler,

page_text: except the front, would materially weaken the force of explosion, and increase
power by making heat sweep the upper surface or top of the boiler by an upper
turn of the flue between the inner surface of case and the upper surface of
boiler.
In witness whereof, I, the said James Fraser, have hereunto set my
hand and seal, this Eleventh day of July, in the year of our Lord One
thousand eight hundred and twenty-seven.
Inrolled the same Eleventh day of July, in the year above written.