Improvements in Steam Generator Furnaces, partly applicable also to the Shells of Steam Generators.
Year: 1899

page_text: Date of Application, 16th Dec., 1899
PROVISIONAL SPECIFICATION.
Improvements in Steam Generator Furnaces, partly applicable also
to the Shells of Steam Generators.
I, BALFOUR FRASER MCTEAR, of Brook Cottage, Rainhill, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has reference, primarily, to metal furnaces of steam generators,
in which the fire is within same, and the pressure of steam acts on the outside of
same, tending to collapse or crush it; and it has mainly for its object and effect
to provide a furnace of this kind which, while it has great strength and power
of diametrical resistance, against collapse, or being pressed out of true cylindrical
form, due to external pressure, shall also possess longitudinal strength, practically
equivalent to simple plain cylindrical furnaces, of such strength as to obviate the
necessity of use of longitudinal stays between the plates between which it ex-
tends. It also has for its object and effect to provide a special improvement or
construction, as hereafter described, in respect of the parts where the lengths of
furnaces are joined together (that is at the ends), and also where they are connected
to the end plates, or end and combustion chamber plates on steam generators.
The furnace flue or tube according to this invention consists of a weldless and
seamless cylinder, having external circumferential ribs at certain distances apart;
and also small, external, corrugations. For instance, in the flue length, say such
as are used in Scotch boilers, there may be three ribs and two corrugations alter-
nating, and pitched apart about equal distances. Then again the parts or ends
of the cylinders, by which they are connected or fastened up, consist of right
angle flanges, having special facing strips or shoulders formed thereon, so that
the flanges at the outer part or face would be considerably thicker than the shell,
the bend or covered part at the angle being of about the same thickness as the
shell.
This construction of flange or end has for its object and effect the dispensing of
separate rings at the joints of furnaces, such as are now commonly used; as well
as providing, generally, an improvement in the construction of furnace flues.
According to a modification here under, in lieu of the solid ribs being formed
on or existing on the exterior of the flue cylinders, the shell may have an internal
annular recess beneath these ribs, curving out into the interior surface in either
direction. And further, the intermediate corrugations referred to, may, in some
cases, be dispensed with; in which case in a furnace of considerable length these
ribs would be spaced considerably apart, say, for example, from about 18 inches
to 2 ft. 6 in.; and in cases where the cylinders are in comparatively short lengths,
say about 3 ft. long, a single solid rib would be provided in the centre.
In the manufacture of the furnaces or cylinders, the ends are left thicker than
the body on the inside surface, by rolling and then, when these ends are turned
or rolled out into flanges at right angles, the thicker portions or ends each form

page_text: a shoulder or type of fitting strip on the outer surface, which takes the place of
jointing rings.
Also,
Furnaces constructed as described will not be liable to the accumulation of
scale upon their crowns to a greater extent than plain cylindrical furnaces.
by having no longitudinal joint, leakage on their becoming more or less rusted
or corroded, which frequently happens with furnaces having welded joints, will
not take place. Furthermore, the furnace having great longitudinal strength
will not require longitudinal stays close alongside it, as have to be provided in
connection with corrugated furnaces.
The construction of cylinders, although solely described as applied to furnaces,
may also be applied with slight obvious modifications, or used in the manufacture
of the shells of steam generators.
11
e T
1000
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
Improvements in Steam Generator Furnaces, partly applicable also
to the Shells of Steam Generators.
I, BALFOUR FRASER MCTEAR, of Brook Cottage, Rainhill, in the County of
Lancaster, 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:
This invention has reference, primarily, to metal furnaces of steam generators,
in which the fire is within same, and the pressure of steam acts on the outside of
same, tending to collapse or crush it and it has mainly for its object and effect
to provide a furnace of this kind which, while it has great strength and power
of diametrical resistance, against collapse, or being pressed out of true cylindrical
form, due to external pressure, shall also possess longitudinal strength, practically
equivalent to simple plain cylindrical furnaces, of such strength as to obviate the
necessity of use of longitudinal stays between the plates between which it ex-
tends. It also has for its object and effect to provide a special improvement or
construction, as hereafter described, in respect of the parts where the lengths of
furnaces are joined together (that is at the ends), and also where they are connected
to the end plates, or end and combustion chamber plates on steam generators.
The furnace flue or tube according to this invention consists of a weldless and
seamless cylinder, having external circumferential ribs at certain distances apart:
and also small, external, corrugations. For instance, in the flue length, say such
as are used in Scotch boilers, there may be three ribs and two corrugations alter-
nating, and pitched apart about equal distances. Then again the parts or ends
of the cylinders, by which they are connected or fastened up, consist of right
angle flanges, having special facing strips or shoulders formed thereon, so that
the flanges at the outer part or face would be considerably thicker than the shell,
the bend or curved part at the angle being of about the same thickness as the
shell.
This construction of flange or end has for its object and effect the dispensing of
separate rings at the joints of furnaces, such as are now commonly used, as well
as providing, generally, an improvement in the construction of furnace flues.
According to a modification here under, in lieu of the solid ribs being formed
on or existing on the exterior of the flue cylinders, the shell may have an internal

page_text: annular recess beneath these ribs, curving out into the interior surface in either
direction. And further, the intermediate corrugations referred to, may, in some
cases, be dispensed with; in which case in a furnace of considerable length these
ribs would be spaced considerably apart, say, for example, from about 18 inches
to 2 ft. 6 in.; and in cases where the cylinders are in comparatively short lengths,
zay about 3 ft. long, a single solid rib would be provided in the centre.
In the manufacture of the furnaces or cylinders, the ends are left thicker than
the body on the inside surface, by rolling and then, when these ends are turned
or rolled out into flanges at right angles, the thicker portions or ends each form
a shoulder or type of fitting strip on the outer surface, which takes the place of
jointing rings.
Furnaces constructed as described will not be liable to the accumulation of
scale upon their crowns to a greater extent than plain cylindrical furnaces. Also,
by having no longitudinal joint, leakage on their becoming more or less rusted
or corroded, which frequently happens with furnaces having welded joints, will
not take place. Furthermore, the furnace having great longitudinal strength
will not require longitudinal stays close alongside it, as have to be provided in
connection with corrugated furnaces.
The construction of cylinders, although solely described as applied to furnaces,
may also be applied with slight obvious modifications, or used in the manufacture
of the shells of steam generators.
My improvements are illustrated in the annexed drawings. In these,―
Figure 1 is a longitudinal section, and Figure 2 an end view shewing one
construction or modification; Figure 3 is a longitudinal section shewing another
construction or modification: whilst Figure 4 is a longitudinal section shewing
a third modification.
In the different figures, the same letters or figures of reference are used to
denote the same or corresponding parts, wherever they appear.
Referring to Figures 1 and 2, the furnace flue or tube here shewn is meant to
represent the furnace of a Scotch boiler, i.e. the type of steam generator commonly
used in the marine service. represents the normal cylindrical plate or shell of
the flue. bare the external circumferential ribs or bulbs. care the small external
corrugations. are the turned out or right-angle flanges at either end, and d' the
annular shoulders or strips on the faces of these right-angle-flanges. In this
furnace, it will be seen that there are three of the external circumferential solid
ribs or bulbs b, one near the end flanges and one in the middle; whilst between
the middle rib or bulb and each of the end ribs, there is one of the external hollow
corrugations c. Therefore the ribs or bulbs b, and corrugations c, alternate, and
are about evenly pitched apart between the two ends of the furnace.
The solid ribs or bulbs are not of great depth; the proportion shewn in rela-
tion to the plate being suitable, and is fairly easily made; and they are curved on
the outside edge, say about semi-circular, and the angles where they merge into
the plate a, are curved and filled as shewn.
The corrugations e consist of simple channels rolled and bent out of, and of
substantially the same thickness as the plate a.
The annular shoulder or fitting strips on the outer faces of the flanges & are
not of the full depth of the face of the flanges, as the drawings shew; but in
thickness the flange, together with the facing strip, give a total width of flange
considerably thicker than the shell plate a; and the bend at the angle between
the flange and the shell body, is on a comparatively large curve, and is of about
the same thickness as the shell a.
With regard to the manner of manufacture of these end flanges of the flues or
furnaces herein shewn and described, the method or process has been above de-
scribed.
In the modification shewn in Figure 3, there are only two of the ribs or annular
bulbs b, the furnace in this case being shorter than that shewn in Figure 1;

page_text: and it is without any corrugations c shewn in Figure 1. Further, within the shell
or flue a, and directly within or under the annular ribs or bulbs b, there is an
internal small annular recess 6 curving out into the interior surface of a in either
direction. The flanges of the furnace, or furnace length, as the case may be, are
the same as those set forth with reference to and shewn in Figure 1.
Figure 4 shews the construction of short furnace length; say about 3 ft. long,
having the flanges & with annular fitting faces or shoulders a', and a single rib
or annular bulb 6 intermediate these flanges. Of course, in a furnace flue of the
usual length, several of these lengths would be rivetted or connected together at the
Hanges, as is shewn on the right hand side in Figure 4. And where these faces d'
meet, and between the curved parts d, this construction provides an annular
recess, so that the flames of combustion would not directly act or impinge on the
thick part of the flanges.
The furnace flues or tubes herein shewn are all assumed to be weldless and
seamless cylinders, rolled or made by any suitable known process or method.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is ;-
1. A steam generator or shell, or length of same, having upon it external annular
ribs or bulbs, and flanges, constructed substantially as herein set forth and shewn.
2. A steam generator furnace having a right angle flange with a projecting
annular shoulder or facing strip, as and for the purposes herein set forth.
3. The manufacture of furnace or flue or tube end flanges, as herein described,
namely, by rolling the flue in cylindrical form, with the ends having an internally
projecting piece; and then subsequently rolling or turning the flanges outwards
at right angles to the cylindrical body; substantially as and for the purposes
set forth.
4. The furnace flue, or length of same, having the parts, and construction or
formation, particularly as shewn in and set forth with reference to Figures 1 and
2; Figure 3; and Figure 4. respectively, of the drawings.
Dated this 15th day of September 1900.
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.