IMPROVEMENTS IN STEAM GENERATORS
Year: 1877

page_text: LETTERS PATENT to William Smethurst, of Brynn, near Wigan, in the County
of Lancaster, Colliery Proprietor, for the Invention of "IMPROVEMENTS IN
STEAM GENERATORS."
Sealed the 13th October 1877, and dated the 20th April 1877.
PROVISIONAL SPECIFICATION left by the said William Smethurst at the
Office of the Commissioners of Patents on the 20th April 1877.
WILLIAM SMETHURST, of Brynn, near Wigan, in the County of Lancaster, Colliery
Proprietor. "IMPROVEMENTS IN STEAM GENERATORS."
"C
My Invention relates to internal flued steam generators, such for example, as
Cornish" and "Lancashire" boilers, and has for its principal object to increase the
evaporative and economical efficiency of such boilers. To this end I fix a supple-
mentary boiler or cylindrical water chamber within the internal flue, or within each
internal flue, and extending from a pivot behind the bridge or rear end of the
furnace to the back, or nearly to the back end of the said flue, or projecting
outwards for some distance beyond the termination of the said flue. The said
chamber is arranged concentrically within the flue, or is arranged to be nearer the
flue in one part than another, as considered to be most advantageous, and is con-
neçted with the shell of the flue by means of water tubes or pipes, which serve to
sustain the said chamber and to permit the circulation of water into and out of the
chamber.
I consider that four such connecting pipes will be suitable, two at or about the
upper part of the chamber and two at or about the lower part thereof, each pipe
being situated at or near one end of the chamber.
The ends of the chamber may be flat, curved, or hemispherical, but I consider the
latter form to be best.
In addition to the heating surface of the chamber and connecting pipes the said
chamber, by reducing the area for the flow of heated gases and flames, and by
causing such gases and flames to extend lower down the sides of the flues, adds to
the useful effect of the boiler.
The said chamber may be provided with a man-hole for convenience of cleansing
and repairs.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Smethurst in the Great Seal Patent Office on the 20th October
1877.
WILLIAM SMETHURST, of Brynn, near Wigan, in the County of Lancaster, Colliery
Proprietor. IMPROVEMENTS IN STEAM GENERATORS."
"
My Invention relates to internal flued steam generators, such for example, as
"Cornish " and " Lancashire boilers, and has for its principal object to increase the
evaporative and economical efficiency of such boilers. To this end I fix a supple-
mentary boiler or cylindrical water chamber within the internal flue, or within each
internal flue, and extending from a point behind the bridge or the rear end of the
furnace to the back, or nearly to the back end of the said flue, or projecting
outwards for some distance beyond the termination of the said flue. The said
chamber is arranged concentrically within the flue, or is arranged to be nearer the
flue in one part than another, as considered to be most advantageous, and is con-
nected with the shell of the flue by means of water tubes or pipes, which serve to
sustain the said chamber and to permit the circulation of water into and out of the
chamber.
And in order that my said Invention may be readily described and fully under-
stood I have appended hereunto a Sheet of Drawings, made to a scale of about
half an inch to the foot, and marked with letters of reference, corresponding marks
indicating the same parts in the two Figures.
Referring to the said Drawings, Fig. 1 represents a vertical longitudinal section,
and Fig. 2 a back end view of a steam generator constructed in accordance with
my Invention. The said steam generator.in the example selected is of the Lan-
cashire type, that is to say, it is a cylindrical boiler having two internal flues
extending throughout, from end to end. The furnace portion of each flue is fitted
with fire-bars A, as is usual in this type of boiler, the said fire-bars being of any
suitable form and arrangement. Within the after part of each flue is fixed a
supplementary boiler or water chamber B. The chamber B in each case extends
from a point a little behind the bridge C to the rear end of the boiler, and is
connected with the shell of the flue at four points, by means of water pipes or
tubes d, d. In the example the said water pipes are formed with flanches, by means
of which they are riveted to the shells of the chamber and of the flue.
In some cases, or if preferred, in any case, the flanches on the said pipes may be
attached to the shell of the flue by means of bolts or screws, in order that the
chamber may be more readily removed from its position within the flue when
repairs are needed; the said water pipes, besides serving to connect the chamber B
with the shell of the flue, permit the flow of water into and out of the said chamber.
When the steam generator is at work the flames and heated gases passing over the
bridge flow through the annular space between the chamber B and the shell of the
flue, and acting on the surface of the said chamber cause a generation of steam
therein, and a circulation of water into and out of the said chamber. The water
flowing into the chambers being withdrawn from the lower part of the boiler,
containing the cooler portion of the water, and being replaced by heated water
descending from above, the circulation of the water is improved, whereby the
economical working of the boiler is promoted.
In addition to the increased heating surface obtained by the use of the
chambers B, B, the said chambers by reducing the area for the flow of heated gases
and flames through the back portions of the internal flues, and by causing such
gases and flames to extend lower down the sides of the flues, increase the value of
the said portions of the flues as heat conductors, and thereby add to the useful
effect of the said flues. In the example each chamber is formed and provided with
a man-hole and lid at e, for convenience when cleansing the boiler or when effecting
repairs.
I do not confine myself to the number of the water pipes e nor to their form

page_text: and arrangement, and if preferred the chamber B may be connected with the flue
by means of tubes screwed into the shells of the chamber and the flue. The
chamber B may be formed either with flat or with dished or hemispherical ends,
and may be either longer or shorter than represented, in proportion to the length of
the boiler, and in some cases, or if preferred, may extend beyond the back end of
the internal flue, in which case the connections with the boiler may be wholly or
partly effected by means of curved pipes riveted, bolted, or secured by one end to
the chamber, and by the other end to the back end plate or plates of the boiler.
Having now fully set forth and indicated the nature of my said Invention, and
the manner in which the same may be carried into effect, I would have it to be
understood that I claim,-
First. The steam generator formed with internal flues, and provided with the
supplementary water-heating chambers fixed within the flues, substantially as and
for the purposes set forth and indicated herein-before, and in and by the accom❤
panying Drawings.
And, Secondly. The cylindrical water-beating chambers fixed within the internal
flues of steam generators, and connected therewith by means of "water pipes" or
tubes, substantially as and for the purposes set forth and indicated.
In witness whereof, I, the said William Smethurst, have hereunto set my hand
and seal, this Sixteenth day of October, in the year of our Lord One thousand
eight hundred and seventy-seven
Signed and sealed by the
said William Smethurst
in the presence of
EDWARD K. DUTTON,
Agent to the Patentee,
3, Princess Street,
Manchester.
WILL SMETHURST. (L.S.)