AN IMPROVEMENT IN THE HEATING OF BOILERS
Year: 1884

page_text: I, FREDERICK SIEMENS of N° 12 Queen Anne's Gate Westminster in the County
of Middlesex, Engineer, do hereby declare the nature of the said invention for
"AN IMPROVEMENT IN THE HEATING OF BOILERS" to be as follows:-
In a Provisional Specification filed by me on 8th December 1883 N° 5677,
I described a method of constructing and working regenerative gas furnaces in
such a manner that the objects heated and the roof and walls of the furnace are
kept as much as possible clear from direct contact of the flame.
One object which I have in view is to prevent contact of the flame with any
object colder than itself, which has the effect of rendering the combustion more or
less imperfect and so involving waste of fuel. My present invention consists in
applying this method to the heating of boilers which are not worked on the
regenerative system but by the flame resulting from a mixture of gas and air,
which or either of which may be more or less heated before their admixture. In
carrying out my invention I will suppose that a boiler has an internal fire flue like
that of a Cornish boiler or sever alsuch flues. At the mouth of this flue, I admit
the mixed gas and air flame taking care that the port for its admission is of
smaller dimensions than the flue itself, and that the outlet port at the farther end
of the flue is also smaller than the flue. Thus the flame will mostly be confined to
the central space of the flue not touching the metal but hoating it by radiation
only. In cases when the flue is of considerable length, I introduce a ring about its
middle, or several such rings giving apertures for the passage of the flamo
corresponding with the inlet and outlet ports. And I prefer to make the inner
periphery of any such ring very narrow so as to give as little contact as possible
with the flame passing through the aperture of the ring. Beyond the flue, at the
end of which the visible flame may bo considered to cease, the gaseous products of
combustion still retaining considerable heat may be passed through tubes or other
flues of the boiler so as to heat by direct contact with them. Also channels for the
supply of the air or gas or both may pass along these flues so as to receive heat by
conduction.

page_text: COMPLETE SPECIFICATION.
I, FREDERICK SIEMENS, of N° 12 Queen Anne's Gate in the County of Middlesex,
Engineer, do hereby declare the nature of my invention for "AN IMPROVEMENT IN
THE HEATING OF BOILERS" and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :—
In my Specification Nº 5677 of 1883, I described a method of constructing and
working regenerative gas furnaces in such a manner that the objects heated and
the roof and walls of the furnace are kept as much as possible clear from direct
contact of the flame.
One object which I have in view is to prevent contact of the flame with any
object particularly if that object is colder than itself, as this has the effect of 1
rendering the combustion more or less imperfect and so involving waste of fuel.
My present invention consists in applying this method to the heating of boilors
which are not worked on the reversal regenerative system but by the flame
resulting from a mixture of gas and air, which, or either of which, may be more or
less heated before their admixture. In carrying out my invention I will suppose
that a boiler has an internal fire flue like that of a Cornish boiler or several such
flues. At the mouth of this flue I admit the mixed gas and air flame, taking care
that the port for its admission is of smaller dimensions than the flue itself, and that
the outlet port at the farther end of the flue is also smaller than the fluo. Thus
the flame will mostly be confined to the central space of the flue not touching the
metal but heating it by radiation only. In cases when the flue is of considerable
length, I introduce a ring about its middle, or several such rings which may be
concentric or eccentric to the flue itself, giving apertures for the passage of the
flame corresponding with the inlet and outlet ports; or arches could be inserted in
the flue for the same purpose. And I prefer to make the inner periphery of any
Buch ring or arch very narrow so as to give as little contact as possible with the
flame passing through the aperture. Beyond the flue, at the end of which the.
visible flame may be considered to cease, the gaseous products of combustion still
retaining considerable heat may be passed through tubes or other flues of the boiler
Bo as to heat by direct contact with them. Also channels for the supply of the air
or gas or both may pass along these flues so as to receive heat by conduction.
Fig. 1 of the accompanying drawings is a longitudinal section of a boiler which
may have two fire flues as shewn in the transverse sections Figs. 2 and 3, or it
may have one fire flue as in the transverse section Fig. 4. Gas supplied from a
producer passes by a channel A when the valve B is opened, into the combustion
-chamber where it meets and mixes. with air entering by the channel D and the
mixture is in the first instance ignited through the door E. The flame passing
through the throat F, which is smaller than the fire flue, travels along the fire flue
and the products of combustion issue by the throat G and then pass along the
flues H which are arranged in the usual way. When the fire flue is of considerable
length, several rings, or their equivalents may he introduced to keep the flame out
of contact with the metal of the boiler. These may be rings concentric with the
flue as K, or eccentric as L or arches as M placed in the fiue in such positions as to

page_text: compel the flame to travel as much as possible along the middle of the flue. It is
of advantage to heat the air supply. This may be done by causing the air to pass
along channels parallel to the boiler flue so as to have heat conducted to it from
the products of combustion, these channels being preferably provided with baffle
projections O to direct the air more completely against the heated surface. The
flue H may also have baffle projections P to direct the hot products of combustion
against the bottom of the boiler and to impart more heat to the channel for tho
incoming air. The inflowing gas might also be heated in a similar way if desired.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
In heating a boiler wholly or partly by flame, arranging the flame flue in such
manner that the radiant heat of the flame is chiefly utilised therein substantially
as and for the purposes herein set forth.
Dated this 28th day of February 1885.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.