Improvements in boiler flues and fire-boxes
Year: 1887

page_text: Date of Application, 2nd Sept., 1887
Complete Left, 1st June, 1888
Complete Accepted, 6th July, 1888
HOMAN PRICE FENBY, of the Manor House, Farnley near Leeds in the County of
York, Engineer do hereby declare the nature of this invention to be as follows:-
My Invention has for its object Improvements in boiler flues and fire-boxes, by
which they are greatly strengthened to resist collapse, and includes the method of
manufacture of such articles, by which I largely reduce first cost of plant and
machinery, and at the same time produce a more perfect article at less cost than by
any process at present in use.
In the manufacture of corrugated flues with annular corrugations of a wave-line
section such as are now commonly in use, the practice is to weld up a plain flue or
tube of metal and afterwards corrugate it in a special mill having similarly corrugated
rolls, such mill being provided with means of getting the flue on and off.
My Improved flue or fire-box instead of being corrugated in the manner and form
above referred to, ha what I call a serrated section, that is, when finished, it presents
the appearance of having a number of V shaped grooves lying side by side and
running round the flue, the tops and bottoms being rounded off. This form gives
additional strength to the flue above the ordinary wave-line corrugation.
In order to produce these deep grooves I take a hot plate of metal and pass it
through and through a pair of rolls (preferably reversing) having similarly V shaped
grooves in them, the grooves of one roll being opposite the ridges of the other, until
the plate is grooved sufficiently deep, and presents in end view a kind of saw tooth
section.
I then take the plate whilst hot, or I re-heat it, and pass it through a pair of
bending rolls (ordinary or special) the rolls having similar V shaped grooves in them
to suit the plate, and bend it up till a complete flue is formed and a small lap is given
to the now contiguous ends of the plate.
I next weld these ends together by a power hammer of suitable description, the
hammer head and anvil horn both being provided with tools which fit the V shaped
ΚΥΛΟΨΑ

page_text: The flues are now finished ready for flanging &c., as may be requisite.
The flues may be finally rolled in the bending rolls after welding to ensure their
being very round and true.
For welding I use ordinary fuel or gas.
It will thus be seen that I dispense with the corrugating mill (which must of
necessity be of a very costly description) and use my special rolls in an ordinary
rolling mill, whilst the same bending rolls which are at present used for bending
up the plain flues preparatory to being corrugated, do equally well for my purpose by
simply grooving the rolls to suit the serrated plates.
An important feature in my new method of manufacture is that I secure a more
perfect weld than when the flue is corrugated after being welded as is now the custom
it being found in actual practice that the weld is invariably very much distressed and
frequently torn open during the process of corrugating. This of course cannot occur
when the welding is done after the grooves are formed, and the plate is in the form
of a flue.
;

page_text: COMPLETE SPECIFICATION.
Improvements in Boiler Flues and Fire-boxes and in the Manufacture
thereof.
I, HOMAN PRICE FENBY, late of the Manor House, Farnley near Leeds in the
County of York, but now of 54 Holborn Viaduct, in the City of London, 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 Invention has for its object Improvements in boiler flues and fire-boxes of
boilers, by which they are greatly strengthened to resist collapse, and includes the
method of manufacture of such articles, by which I largely reduce first cost of plant
and machinery, and at the same time produce a more perfect article at less cost than
by any process at present in use.
In the manufacture of corrugated flues with annular corrugations of a wave-line
section such as are now commonly in use, the practice is to weld up a plain flue or
tube of metal and afterwards corrugate it in a special mill having similar annularly
corrugated rolls, such mill being provided with means for getting the flue on and off
the inside roll.
My Improved flue or fire-box instead of being corrugated in the manner and form
above referred to, has what I call a serrated section, that is, when finished it presents
the appearance of having a number of V shaped grooves lying side by side and running
round the flue, the tops and bottoms of the grooves being rounded off. This form
gives an additional strength to the flue above the ordinary wave-line corrugation.
In order to produce these deep grooves I take a hot plate of metal and pass it one
or more times through a pair of rolls (preferably reversing) having similar V shaped
grooves longitudinally in their peripheries, the grooves of one roll being opposite the
ridges of the other, until the plate is grooved sufficiently deep, and presents in end
view a kind of saw tooth section.
I then take the plate whilst hot, or I re-heat it, and pass it through a pair of
ordinary (or special) bending rolls (the rolls having similar V shaped grooves in them
to suit the plate) and bend it up till a complete flue is formed, and a small "lap" or
"butt" joint is given to the now contiguous ends of the plate. I next weld these ends
together by the aid of a special machine and power hammer of suitable description,
the hammer head and anvil horn both being provided with tools which fit the V shaped
grooves. The flue is now finished ready for flanging &c., as may be requisite.
The flues may be finally rolled in the bending rolls after welding to ensure their
being very round and true.
For welding I use ordinary fuel or gas.
It will thus be seen that I dispense with the corrugating mill at present used, (and
which must of necessity be of a very costly description,) and may use my special rolls
in an ordinary rolling mill, whilst the same bending rolls which are at present used
for bending up the plain flues preparatory to being corrugated, do equally well for my
purpose by simply grooving the rolls to suit the serrated plates.
An important feature in my new method of manufacture is that I secure a more

page_text: perfect weld than when the flue is corrugated after being welded as is now the custom ;
it being found in actual practice that the weld is invariably very much distressed and
frequently torn open during the process of corrugating. This of course cannot occur
when the welding is done after the grooves are formed and the corrugated plate is in
the shape of a finished flue or fire-box.
In using my Improved method of manufacture, I do not bind myself to the above
described serrated section of corrugation, as it is evident the same machinery or plant
is capable of producing flues or fire-boxes having many other forms of corrugations
by altering the contour of the rolls.
I will now proceed to describe with reference to the accompanying sheet of drawings
my Improved form of corrugated flue or fire-box, and the process of manufacture used
in its production.
In the accompanying drawing Fig. 1. is an end section of the corrugating rolls,
shewing a plate passing through and partly corrugated. Fig. 2. shows the corrugated
plate being bent in the special rolls into the form of a flue or fire-box.
Figs. 3 and 4, show other arrangements of bending rolls which may be used
without departing from my Improved system of manufacture.
Figs. 5 and 6, show the welding tools formed to fit the corrugations in the flue.
In the foregoing Figs., the scale adopted is about one sixteenth of the actual size,
while Fig. 7. shows the section or end view of the corrugated plate one half scale.
It will be readily seen and understood on reference to Fig. 1. that the plate upon
being presented in a highly heated state to the longitudinally serrated rolls, is seized
by them and each corrugation is formed by the metal being quietly folded over, that
is, up and down, a process which does not appreciably distress or stretch the metal.
A much deeper corrugation can thus be formed than by the system now in use, viz.,
corrugating an already formed tube by rolls having annular ridges and grooves, which
draw the corrugations out of the thickness of the metal.
The corrugations may be formed if desired at one pass of the plate through the rolls,
but I prefer to pass it through the rolls two or more times before bending it up into a
flue or fire-box in the bending rolls.
The bending may be accomplished in an ordinary pair of bending rolls of either the
horizontal or vertical type, by having the rolls specially formed with annular
corrugations or ridges and hollows to fit the already corrugated plate.
Fig. 2. shows in end section the plate being bent in such rolls, Figs. 3 and 4 being
only modifications of the arrangement or disposition of the rolls.
The flue or fire-box may be so bent in these rolls as to give a small lap over for the
after process of welding, or the edges of the plate may be simply brought together
so as to form a "butt "joint. In using the "butt" joint I prefer to weld in with
the corrugated plate a "glut" of best iron, which serves the double purpose of making
a very sound joint along the flue or fire-box, and also prevents it losing in thickness
at this part by the welding process.
The welding of the joint is effected by a power hammer H, Figs. 5 and 6, which
carries a tool I, with a corrugated surface exactly corresponding with the corrugations
in the flue. The anvil K, which is inside the flue, is similarly provided with a tool L,
so that no distortion of the corrugations can take place, the welded joint being of
exactly the same contour as the remainder of the fluo or fire-box.
In Fig. 7. which shews in section the form of my Improved corrugation to one half
scale, the dotted lines indicate approximately the amount of rounding off top and
bottom of the serrated section or V form which 1 employ.
Complete machinery for carrying out the above mentioned processes is fully described
and illustrated in a Patent applied for by me on the 17th day of January, 1888, and
numbered 695.
_
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed I declare that what I claim is :-
1. Giving to the corrugations of flues and fire-boxes of boilers a serrated or saw
tooth section as described and also as illustrated by the accompanying drawings.

page_text: 2. Producing such corrugations in a flat plate by means of longitudinally fluted
rolls as described and also as illustrated by the accompanying drawings.
3. Bending such corrugated plate into the form of a flue or fire-box by means of
bending rolls having annular ridges and grooves corresponding with the corrugations
in the plate as fully described and also as illustrated by the accompanying drawings.
4. Welding the longitudinal joint of the bent up flue or fire-box so as to preserve
continuously the form of the corrugations, by means of power hammer and anvil,
both hammer head and anvil being fitted with suitable tools or swaging dies whose
working faces correspond with the corrugations in the flue or fire-box, as fully described
and also as illustrated by the accompanying drawings.
5. The process as described for the manufacture of corrugated flues and fire-boxes
of boilers.