improvements in Water-tube Steam Generators.
Year: 1897

page_text: Date of Application, 28th Aug., 1897-Accepted, 9th Oct., 1897
COMPLETE SPECIFICATION.
improvements in Water-tube Steam Generators.
We, ARNOLD FRANK HILLS, of Monkhams, Woodford, in the County of Essex,
Engineer, and GEORGE SCHOLEY YOUNG, of 50, Clapton Common, in the County
of London, 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:--
Our invention relates to steam boilers or generators of the kind wherein two
lower vessels are each connected with one upper vessel by a number of tubes of
relatively small diameter and in which the water is contained within the tubes.
According to this invention we arrange the inner groups of the tubes of such a
length relatively with the diameter of the upper vessel and of such a form that
each tube singly can be drawn into the upper vessel and we combine with each
inner group of tubes an outer row. or group of tubes which cannot be drawn into
the upper vessel but require the removal of part of the casing or of the casing door
so that the top and bottom ends of the said outer tubes can be drawn from the
holes in the upper and lower vessels respectively. These outer tubes are of greater
length than the tubes of the inner groups, so that spaces constituting what may be
termed supplementary combustion chambers are formed between them and the
said inner groups of tubes, and are bent so that for a portion of their length they lie
approximately parallel with the casing. Their ends are preferably arranged. in
straight lines leaving a small parallel space between each pair of tubes for their
whole length; if desired, however, the ends of the outer row of tubes can be arranged
in zigzag lines..
Between the lower ends of the outer tubes and those portions thereof which are
parallel with the casing and the casing itself we place fire clay or other refractory
and non-conducting material to prevent the furnace gases from coming into contact
with the casing, and the spaces between the upper part of the outer tubes are also
closed by non-conducting material to protect the tube plate of the upper vessel
and the highest part of the tubes near the working water level from the heated
gases; it will thus be understood that the only available passage for the heated
furnace gases from the supplementary combustion chambers to the uptake is
through the spaces between the two lots of filling material.
To enable our invention to be fully understood we will describe the same by
reference to the accompanying drawings, in which:-
Figure 1 is a view, half in elevation and half in transverse section, of a steam
boiler or generator embodying our improvements; and,
Figure 2 is a sectional side elevation.
a, a are the two lower vessels, b is the upper vessel and c, c are pipes or tubes of
the inner group (there is a group upon each side of the boiler but only one group
is shewn in the drawing) connecting the vessels a, a with the vessel b and all of
which are designed to be drawn into the vessel b. d is the furnace, e is the casing
surrounding the boiler and f, f are the flues or uptakes leading to the funnel g.
h, are the tubes forming the outer row or group two sets of which are employed

page_text: namely, one set in conjunction with each group of connecting tubes c, c. As,
however, the two sets of outer tubes are identical, one set only is described and
shewn in the drawings.
The said tubes h, h (which are bent to lie at some distance from the tubes c, c
so as to form a space i, Figure 1 constituting one of the supplementary combustion
chambers hereinbefore referred to and so that for a part of their length they are
parallel with the casing) are inserted into two sets of holes a¹, b1, Figure 2, in the
vessels a, b in the same manner as the tubes c, c and are placed at distances apart
to afford a passage proportionate to the grate area. To leave sufficient metal in
the tube plates between the holes for the outer tubes h, h to afford the requisite
strength without forming the holes for alternate tubes on different lines (which
necessitates. the formation of uneven open spaces between the end portions of
adjacent tubes) we advantageously employ tubes which are smaller at the ends than
at other points as shewn clearly in Figure 1.
jis the filling of fire brick or fire clay between the casing e and the portion of
the outer row of tubes / parallel therewith, and k is the fire brick or other non-
conducting refractory material for protecting the tube plate and the upper parts
of the outer tubes near the water line from the heated gases.
In order to improve the combustion in the supplementary chambers i, i formed
by the tubes h, h we can provide for introducing fresh air directly into the said
supplementary combustion chambers, for instance, through holes or openings in
the casing, which may have suitable dampers or valves for regulating the quantity
of fresh air admitted.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:
1. In a water tube boiler of the type described and illustrated the combination with
the groups of tubes c, c connecting the lower water vessels to the upper vessel and
each capable of being withdrawn into the said upper vessel, of other rows or groups
of tubes h, h which can also be independently removed but not withdrawn into the
upper vessel, substantially as described.
2. In a water tube boiler of the type described and illustrated, an outer row of
tubes arranged with spaces between adjacent tubes for the whole of their length
the lower and upper parts of these spaces being filled with refractory and non-
conducting material leaving the intermediate spaces only for the passage of the
gases, substantially as, and for the purpose, described and illustrated.
3. A boiler having the arrangement of tubes and refractory material substantially
as described and illustrated.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.