Improvements in and relating to Steam Boilers, applicable also to Evaporators, Condensers, Feed-heaters, and the like.
Year: 1891

page_text: Date of Application, 10th Apr., 1891
Complete Specification Left, 11th Jan., 1892-Accepted, 9th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in and relating to Steam Boilers, applicable also to
Evaporators, Condensers, Feed-heaters, and the like.
I, JOHN WATT, of 174 Cleveland Street, Birkenhead, in the County of Chester,
Engineer, do hereby declare the nature of this invention to be as follows:-
My present invention relates to an improved construction of steam boilers more
especially with regard to the attachment of the tubes and stays to the tube plates
or stayed surfaces as the case may be; and the objects of my invention arc,-to
ensure a secure and fluid-tight attachment of the tubes or stays to comparatively
thin plates without exposing the ends of said tubes or stays to the direct aud
prejudicial influence of the flame which impinges on the tube plate, to strengthen
the plates to resist pressure, and to render the said plates more elastic.
My invention is particularly applicable to the construction of fire-boxes in
locomotive type of boilers, and to the construction of tubulous boilers; and the
part of my present invention relating to the method of securing tubes to the tube
plate is also applicable to evaporators, condensers, feed-heaters and the like.
I will first describe the arrangement adopted according to my invention to secure
the tubes and stays of, say, a locomotive type of boiler to the plates thereof.
Instead of simply punching or drilling holes in the plate where the tubes or stays
have to be attached, I indent the plate by nieans of a suitable punch and die and so
form, where the tube or stay is to be attached, a circular flange projecting beyond
the plane of the plate, which will hereinafter be referred to as the indented
Hange.
The joint between the tube and the plate is formed either by expanding the tube
within the indented flange, which may be made taper for this purpose, or by
screwing the tube into the flange, the latter method of attachment is adopted
principally for stay tubes; in any case the joint is preferably made between the
tube and that portion of the indented flauge more remote from the tube plate, so
that the end of the tube does not reach the plane of the tube plate by an amount
approximately equal to one half of the distance that the flange projects from the
plate. In some cases I prefer to make the holes in the indented flange a little
smaller than the outside diameter of the tube, in which case I first drive a hollow
mandrel into the hole and temporarily expand the same to the diameter of the tube.
The point of the mandrel is reduced to receive the end of the tube. A long screw
bolt is now inserted through the tube and mandrel and by means of a cross-bow and
nut the tube is drawn into its place in the indented flange.
I form the indented flange by indenting the plate as follows;-
I provide a punch having a bullet-shaped or parabolic-shaped head and a body
of the same diameter and configuration as is desired to give the indented flange
internally the plate is heated and placed between this punch and a die having the
same internal diameter and configuration as is desired to give the indented flange
externally, the punch is forced into the die and so indents the plate and forms the
indented flange.
It will be seen that, unlike ordinary punching, there is little or no shearing
action, the material of the plate being first stretched and then formed into the
desired shape; in some cases with very thick plates it is desirable to punch a small
hole in the first instance and form the indented flange in two operations, different
punches and dies of suitable configuration being used in each operation.
It is necessary that the material should have considerable tensile strength and
ductility and I therefore prefer to use mild steel or copper.
Usually prefer to indent all the indented flanges necessary for the tube

page_text: attachments at the same operation and at the same time that the plate is being
flanged peripherally for the purpose of attachment.
In this case I form the punches with spigots which fit in holes drilled in a suitable
holding plate, or form the punches integral with the plate, the pitch of the holes or
punches being coincident with the pitch of the tubes to be attached to the tube
plates. The holes forming the dies are also drilled or cast to the same pitch in a
second plate; the plate holding the punches is preferably placed lowermost so that
the punches may not fall out. The plate to be indented is raised to a suitable heat
and placed between the punches and dies, and pressure is exerted between the two
Jatter, means being provided to guide the dies coincidently with the punches; in
this way all the indented flanges, and the attachment flange of the plate if thought
desirable, are formed at the same operation.
Before actually forming the indented flanges I prefer in some cases to prepara-
torily stretch the plate at the parts where the said flanges are to be formed; I do
this by using blunt punches and substituting for the die plate described a square or
other suitable grating having a pitch coincident with that of the punches. This
operation corrugates the plates in a chequered manner, the indented flanges being
subsequently formed in the manner described, at the apices of the corrugations.
In the construction of a locomotive type of boiler fire-box according to my
invention, I substitute for the flat plates at present in use, the chequered corrugated
plates with the indented flanges as described; these flanges project into the water
or steam space and where the plates have to be stayed the flanges are screwed
internally and the stays screwed therein, the stays may be hollow or solid, and
when solid the ends may have holes drilled up them whereby the latter are
expanded in the indented flanges.
Where the plates are comparatively close together the indented flanges project
so as to be in contact and the stays are screwed through the two flanges and
expanded as described.
The crown of the fire box is similarly constructed and the stays to support it are
screwed into the indented flanges, the upper ends of the stays being supported
either by a girder or by the top of the boiler.
Instead of the plates having chequered corrugations they may be corrugated
either vertically or horizontally or in any other direction.
My invention is also particularly applicable to tubulous boilers, especially where
the tubes pass through the two adjacent plates forming the end compartment in
order to stay them, in such cases I construct the said plates with the indented
flanges to which the tubes are secured by screwing or expanding.
Although I have described my invention as applied to a locomotive type of
boiler, it is to be understood that it is applicable to other forms of boilers and also
to condensers, evaporators, feed heaters and the like apparatus in which tubes
have to be attached to plates, or in which flat surfaces have to be stayed to resist
pressure.
Dated this 9th day of April 1891.
SLOAN & LLOYD BARNES,
Castle Chambers, 26, Castle Street, Liverpool, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Steam Boilers, applicable also to
Evaporators, Condensers, Feed-heaters, and the like.
I, JOHN WATT, of 174 Cleveland Street, Birkenhead, in the County of Chester,
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 :-
My present invention relates to an improved construction of steam boilers more

page_text: especially with regard to the attachment of the tubes and stays to the tube plates
or stayed surfaces as the case may be; and the objects of my invention are,-to
ensure a secure and fluid-tight attachment of the tubes or stays to comparatively
thin plates without exposing the ends of said tubes or stays to the direct and
prejudicial influence of the Hame which impinges on the tube plate, to strengthen
the plates to resist pressure, and to render the said plates more elastie.
My invention is particularly applicable to the construction of fire-boxes in
locomotive type of boilers, and to the construction of tubulous boilers; and the
part of my present invention relating to the method of securing tubes to the tube
plate is also applicable to evaporators, condensers, feed-heaters and the like.
In the accompanying drawings which illustrate my invention
Fig. 1 shows in section a portion of a tube plate with indented flanges and various
ways of attaching the tubes thereto;
Fig. 1 shows in section portions of two plates with indented flanges and stays
secured therein so as to tie the plates together.
Figs. I and IV show the method of forming the indented flanges and apparatus
used therefor.
Figs. Vand VI show the application of my invention in the construction of a
boiler of the locomotive type, Fig. V being a section through the fire box thereof
on the line A A of Fig. VI and Fig. VI being a plan in section partially on the
line CC and partially on the line B B of Fig. V.
Figs. VII and VIII show the application of my invention to tubulous or water-
tube boilers, Fig. VII being a partial diametral section through the tubes and
Fig. VIII being a section on the line D D of Fig. VII.
Throughout the drawings similar parts are indicated by the same reference
figures, and in the case of sectious, the direction in which they are viewed is
indicated by the small arrows placed adjacent to the letters denoting the plane of
section.
I will first describe the arrangement adopted according to my invention to secure
the tubes and stays of, say, a locomotive type of boiler to the plates thereof.
Instead of simply punching or drilling holes in the plate where the tubes or stays
have to be attached, I indent the plate 1 (Figs. I and II) by means of a suitable
punch and die, as hereinafter described, and so form where each tube or stay is to
be attached, a circular flange 2, projecting beyond the plane of the plate, which
will hereinafter be referred to as an indented flange.
The joint between the tubes and the plate is made by expanding the tubes as
shown in the case of 3 and 3' within the indented flange or by screwing the tube
ends into the flanges as shown in the case of the tube 311; in the case of the tube 3,
the indented flange is parallel internally except at the end of the tube which is
expanded over the curvature of the flange; in the modification shown in the case
of the tube 3', the indented flange is slightly tapered internally which gives the
attachment considerable holding power against tensile stress; where still greater
holding power is required, as in the case of stay tubes, the screwed attachment is
adopted the opposite end of the tube 311 is enlarged in diameter so as to allow it
to be introduced through the opposite tube plate.
It will be seen that as the indented flanges have considerable length not only is
there ample bearing surface for the attachment of the tubes or stays as the case
may be, but their ends are kept well within the plane of the plate and so shielded
from the direct impingement of the flame.
As it is desirable to fix the tubes as tightly as possible in the indented flanges
prefer in some cases to make the internal diameter of the latter a little smaller
than the external diameter of the tubes, in which case I take advantage of the
elasticity of the flange and first drive a hollow mandrel through the hole and so
temporarily expand the same to the diameter of the tube; the point of the mandrel
s reduced to receive the end of the tube and by means of a cross bow and a long
bolt inserted through the mandrel and tube, the latter is drawn into place and
fterwards expanded if thought desirable.

page_text: I form the indented flanges by indenting the plate as follows;- Usually I prefer
to indent all the flanges necessary for the tubes or stay attachments at the same
operation and at the same time that the plate is being flanged peripherally for the
purpose of attachment. Figs. III and IV show the method of forming the indented
Hanges and the apparatus used therefor, Fig. 1 showing the plate before and
Fig. IV after the operation.
4 are punches with pointed heads preferably of the form shown, the bodies being
of the same diameter and configuration as it is desired to give the indented flange
internally the punches are preferably formed with spigots 5 which fit freely in
holes in the holding plate 6, the pitch of the punches being coincident with that of
the tubes or stays.
7 is a die plate having holes coincident with the punches 4; the edges of the
holes are rounded off as shown.
The plate 1 is raised to a suitable heat and placed between the punches 4 and the
die 7 and pressure applied, the die being suitably guided, with the result that the
plate assumes the shape shown in Fig. IV. It will be seen that unlike ordinary
punching there is little or no shearing action, the material is bent over the rounded
corners of the die and stretched into shape by the punch, the thinning of the plate
being greatest at the points of the punches, which ultimately burst through the
plate leaving ragged margins which are subsequently removed by machining the
Hanges down to the level æ, a. If the plate requires also to be flanged peripherally
for the purpose of attachment, this may also be accomplished at the same operation
by making the die 7 and the plate 6 of suitable configuration.
In order to avoid the ragged margins referred to, the plate may, prior to the
indenting operation, have a small hole, say, about equal in diameter to the thickness
of the plate, drilled or punched at each place where an indented flange is to be
formed. In the indenting process the points of the punches enter these holes and
the effect is purely to bend and stretch the plate leaving the edges of the flauges
smooth.
This plan may be adopted if the indented flanges are formed in separate opera-
tions, but where all the flanges are formed at the one operation, it is extremely
difficult, on account of the expansion of the plate when heated, to ensure the exact
coincidence of the holes in the plate and the punches, failing which, the indented
flanges will be distorted.
The punches 4 are preferably fitted freely in the plate 6 to facilitate their
removal from the plate as they sometimes stick therein with 'considerable force;
the plate is lifted away carrying the punches with it and they are then knocked
out individually from either side as may be most convenient. The punches are
preferably placed lowermost so that they may not fall out of the holding plate 6.
It is necessary that the material should have considerable tensile strength and
ductility and I therefore prefer to use mild steel or copper.
The drawing shows punches for forming parallel holes, if the holes are to be
tapered (as already described with reference to the tube 31 of Fig. 1) the punches
have bodies of similar configuration.
Before actually forming the indented flanges, I in some cases preparatorily
stretch the plate at the parts where the said flanges are to be formed; I do this by
using blunt punches and substituting for the die plate 7 a square or other suitable
grating having a pitch coincident with that of the punches. The operation is not
carried far enough to pierce the plate but only to deform it, the effect being to
buckle or corrugate the plate in a chequered manner, the indented flanges being
subsequently formed in the manner described, at the apices of the corrugations.
This part of my invention is specially applicable to plates which have to be
supported by stays as shown in Figs. II, V and V1; the plate between the stays
being curved in two directions at right angles is well adapted to withstand
pressure in either direction and the plate can be made lighter or the stays pitched
inore widely than would be safe with the ordinary construction in which flat plates
are used.

page_text: A further advantage possessed by this form of plate is due to its clasticity in the
direction of its own plane by reason of which it readily accommodates itself to the
unequal expansion and contraction which usually occur in boilers, so avoiding
excessive stresses and strains.
Even when the buckling process is omitted, the plate is much better adapted to
resist pressure than a flat plate stayed in the ordinary way. It will be seen that
the curvature of the flange reduces the flat area between the flanges and in addition
it affords a good countersink into which to rivet or expand the stay ends.
In the construction of a locomotive type of boiler fire-box according to my
invention, as shown in Figs. V and VI, I substitute for the flat plates at present
in use, the chequered corrugated plates with the indented flanges as described:
these flanges project into the water or steam space 8 and where the plates have to
be stayed the flanges are screwed internally and the stays 9 screwed therein. The
stays may be hollow or solid, and when solid the ends may have holes drilled up
them whereby the latter are expanded in the indented flanges.
Where the plates are comparatively close together the indented flanges may
projec so as to be in contact and the stays are screwed through the two flanges
and expanded as described.
The crown of the fire box is similarly constructed and the stays to support it are
secured in the indented flanges, the upper ends of the stays being supported either
by a girder 10 or directly by the top of the boiler.
Instead of the plates having chequered corrugations as described they may be
corrugated either vertically or horizontally or in any other direction or they may
be left flat between the stays.
My invention is also particularly applicable to tubulous or water-tube boilers.
especially where the tubes pass through the two adjacent plates forming the end
compartment, in order to stay them; in such cases I construct the said plates with
the indented flanges to which the tubes are secured by screwing or expanding.
Figs. VII and VIII show this application of my invention.
1 is the inner and the outer tube plate forming between them the water
compartiment 11.
3 are the water tubes, extending across the furnace or combustion chamber to
the opposite water compartment; the tubes are tightly expanded into the indented
flanges and in addition the tubes are swelled at 12 by the expanding tool; the
tubes are further secured to the outer tube plate by the cap nuts 13. It will be
seen that by this construction each tube acts efficiently as a stay to tie the tube
plates together; the tubes are cut away in each water chamber as shown at 14, 14,
in Fig. V111 so as to put their interiors in free communication with the water
chambers.
Although I have described my invention as applied to a locomotive type of
boiler, it is to be understood that it is applicable to other forms of boiler and also
to condensers, evaporators, feed heaters and to like apparatus generally in which
tubes have to be attached to plates, or in which flat surfaces have to be stayed to
resist pressure.
I am aware that prior to my invention, plates intended to receive tubes or stays
have been locally thickened for the attachment of such tubes or stays by embossing
or pressing the plates while hot into suitable matrices so as to provide an increased
thickness where the tube or stay passes through the plate, and to this I make no
claim it is to be observed that according to my invention there is no thickening
of the plate, on the contrary the indented flange, being formed by the bending
and stretching of the material in the flanging process, is necessarily somewhat
thinner than the original plate thickness.
Having now particularly described and ascertained the nature of my said inven-
Lion and in what manner the same is to be performed I declare that what I
claim is ;-
1. The improvement in plates to which tubes or stays are to be attached,

page_text: for use in the construction of steam boilers and the like, which consists in
forming the said plates with indented flanges, substantially as described and
illustrated.
2. The improvement in plates to which tubes or stays are to be attached,
for use in the construction of steain boilers and the like, which consists in
forming the said plates with indented flanges and with the parts between the
said flanges buckled or corrugated, substantially as described and illustrated.
3. The improvement in the construction of locomotive boilers and the like
substantially as described and illustrated in Figs. V and VI.
Dated this 9th day of January 1892.
SLOAN & LLOYD BARNES,
Casile Chambers, Castle Street, Liverpool, Agents for the Applicant.