IMPROVEMENTS IN STEAM BOILERS
Year: 1879

page_text: LETTERS PATENT to John Ellwood, of Granville Terrace, Newtown Street,
Leicester, for the Invention of "IMPROVEMENTS IN STEAM BOILERS."
T
PROVISIONAL SPECIFICATION left by the said John Ellwood at the Office
of the Commissioners of Patents on the 7th July 1879.
JOHN ELLWOOD, of Granville Terrace, Newtown Street, Leicester.
MENTS IN STEAM BOILERS."
"IMPROVE.
This Invention has for its object improvements in steam boilers. In boilers of
the Cornish and Lancashire type having internal flues, I arrange water tubes
within the flues to increase the heating surface in the following manner-From
distance to distance along the length of the flue at each place where I wish to
insert water tubes, I form four holes in the flue wall equally spaced around it,
and I cover the holes with two curved tubes flanged at their ends. The flanges
are rivetted to the inner side of the flue, or the tubes are bolted or otherwise
attached to the flue so that the mouths of the tubes coincide with the holes,
and each tube forms a water passage from one hole to the next; the two tubes
forming a pair approach each other in the centre of the flue, but there is a space
left between them.sufficient for the free play of the flame or heated gases around
the tubes.
I arrange the tubes of alternate sets in different quadrants of the flue, so that the
tubes may shelter each other as little as possible from contact with the heated
gases.
By this arrangement of the water tubes I am enabled to provide within the
flue a larger area of heating surface, than when straight water tubes passing
diametrically across the flues are employed.
I arrange water tubes within the fire boxes of upright boilers, in the manner.
above described.

page_text: -SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Ellwood in the Great Seal Patent Office on the 7th January
1880.
JOHN-ELLWOOD, of Granville Terrace, Newtown Street, Leicester. " IMPROVE-
MENTS IN STEAM BOILERS."
This Invention has for its object improvements in steam boilers.
:-
In boilers of the Cornish and Lancashire type having internal flues, I arrange
_water_tubes within the flues to increase the heating surface in the following
manner From distance to distance along the length of the flue at each place
where I wish to insert water tubes, I form four holes in the flue wall equally spaced
around it, and I cover the holes with two curved tubes flanged at their ends. The
flanges are rivetted to the inner side of the flue, or the tubes are bolted or other-
wise attached to the flue, so that the mouths of the tubes coincide with the holes,
and each tube forms a water passage from one hole to the next; the two tubes
forming a pair approach each other in the centre of the flue, but there is a space
left between them sufficient for the free play of the flame or heated gases around
the tubes.
I arrange the tubes of alternate sets in different quadrants of the flue, so that the
tubes may shelter each other as little as possible from contact with the heated
gases.
By this arrangement of the water tubes I am enabled to provide within the
flue a larger area of heating surface, than when straight water tubes passing
diametrically across the flues are employed.
I arrange water tubes within the fire boxes of upright boilers, in the manner
above described.
In the Drawings hereunto annexed I have shewn examples of steam boilers
having curved tubes placed within their internal flues, in the manner above
described; Figure 1 is an end view; and Figure 2, a longitudinal section of a
Cornish or single flue horizontal boiler, so provided with curved tubes in the
interior of its flue. The internal flues of a Lancashire or double flue boiler might
have curved tubes applied to it in the same manner.
Figure 3 shews a horizontal section, and Figure 4, a vertical section of a vertical
boiler with the curved tubes applied in the manner described to the interior of its
fire box flue.
In each of these Figures A is the outer shell of the boiler; B, the internal flue;
and C, the curved tubes.
In Figures 1 and 2, two pairs of tubes C are vertical, whilst the other two pairs
are inclined. The number of pairs_of_tubes. placed in the flue-may-be-varied-
according to the diameter of tubes used and the length of the flue.
In Figures 3 and 4, the upper and lower pairs of curved tubes are at right
angles to one another, whilst the cetral pair of tubes is at an intermediate angle.
The angle at which the several pairs of curved tubes are set to one another may
however in each case be varied. When the curved tubes are applied to the flue of
a vertical boiler, I prefer that each curved tube should slightly incline downwards,
as shown at Figure 4, so that sediment may not rest in these tubes.
The four holes formed in the flue to receive the ends of each pair of curved tubes
are shewn to be at equal distances apart around the flue, and it is better for them
to be thus equally spaced around the flue, still it is not essential that the distances
between thein should be alsolutely the same as the centres of the pair of holes,
which receive the ends of each curved tube may be at a somewhat greater or less
distance than a quarter of the circumference of the flue.
In Figures 1, 2, 3, and 4 the ends of the curved tubes are shewn to be welded to
the internal flues, but as before stated they be otherwise affixed to the flue; Figures

page_text: 5 and 6 show how the curved tubes may be formed with a flange at each end to be
rivetted or bolted to the flue; this arrangement is particularly applicable when the
curved tubes are to be applied to boilers already constructed.
The curved tubes may be of iron brass, copper, or other suitable metal.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim,-
The application of pairs of curved tubes in the interior of the internal flue or
flues of steam boilers, substantially in the manner herein before described.
In witness whereof, I the said John Ellwood, have hereunto set my hand and
seal, this the Third day of January, in the year of our Lord One thousand
eight hundred and eighty.
J. ELLWOOD. (L.S.)