IMPROVEMENTS IN TUBULAR
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said James Armer at the Office
of the Commissioners of Patents on the 29th December 1882.
JAMES ARMER of Dartford in the County of Kent
BOILERS
"
"IMPROVEMENTS IN TUBULAR
My Invention relates to a construction of tubular boilers whereby I am enabled
to accommodate between two parallel tube plates an increased amount of tube
surface, and in the case of vertical boilers to dispose that surface in a way better
suited for heating than when the tubes are straight extending from the one tube
plate to the other. For this purpose I bend the tubes so as to give them a gentle
helical twist either throughout their whole length or throughout the greater part
of their length keeping the ends which enter the tube plates still parallel to the
line of the straight tube. The length of the tubes between the plates is thus
extended, and when the boiler is vertical the flame and hot products of combustion
instead of passing directly up straight vertical tubes are compelled to take a belival
course thus acting with increased heating effect. The helical flexure of the tubes
may be effected in various ways. One way which I adopt is to form a helical
groove in a cylindrical surface and having heated the tube to mould it into this
groove. When the boiler is of cylindrical form, the tubes of each ring will have
the same helical form and may therefore be all moulded in one groove.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Armer in the Great Seal Patent Office on the 26th June
1883.
JAMES ARMER of Dartford in the County of Kent "IMPROVEMENTS IN TUBULAR
BOILERS"
My invention relates to a construction of tubular boilers whereby I am enabled
to accommodate between two parallel tube plates an increased amount of tube
surface, and in the case of vertical boilers to dispose that surface in a way better
suited for heating than when the tubes are straight extending from the one tube
plate to the other. For this purpose, I bend the tubes so as to give them a gentle
helical twist either throughout their whole length or throughout the greater part
of their length, keeping the ends which enter the tube plates still parallel to the
line of the straight tube. The length of the tubes between the plates is thus
extended, and when the boiler is vertical, the flame and hot products of combustion,
instead of passing directly up straight vertical tubes, are compelled to take a
helical course, thus acting with increased heating effect. The helical flexure of the
tubes may be effected in various ways. One way which I adopt is to form a
belical groove in a cylindrical surface, and, having heated the tube, to mould it into
this groove. When the boiler is of cylindrical form, the tubes of each ring will
have the same helical form, and may therefore be moulded in one groove.
Fig. 1 of the accompanying drawing is a vertical section and Fig 2 is a sectional
plan of a vertical cylindrical tube boiler taken as an example of the application of
my invention. In this case there are three rings of tubes T as shewn in Fig. 2.
All the tubes of each ring receive the same helical twist such as is shewn for those
of the outer ring in Fig 2. The tubes of the other rings are in like manner
helically twisted, the flexure of their respective helices being such as to adapt their
ends to the holes in the upper and lower tube plates P, P. Obviously, there may
be a greater or less number of rings of tubes in a cylindrical boiler, and in boilers
of other forms, the tubes may be arranged in the various ways usually adopted in
such boilers, each tube having a helical twist suited to its position.
Having thus described the nature of my invention and in what manner the same
is to be performed, I claim :-
Bending the tubes of boilers so as to give them a helical twist, substantially as
and for the purposes herein set forth.
In witness whereof I the said James Armer have hereunto set my hand and
seal this twenty third day of June in the year of our Lord One thousand
eight hundred and eighty-three.
JAMES ARMER (L.S.)