Improvements in the Internal Flues of Steam Boilers.
Year: 1889

page_text: Date of Application, 29th Mar., 1889
Complete Specification Left, 30th Dec., 1889-Accepted, 1st Feb., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Internal Flues of Steam Boilers.
I, ERNEST RICHARD JOICEY, of No. 8, St. Edmund's Place and Beverley Boiler
Works, East Street, Gateshead, in the County of Durham, Engineer and Boiler Maker,
do hereby declare the nature of said invention to be as follows:-
My invention specially relates to improvements in the construction of the internal
flues of boilers having one or more flues, and boilers made according to my invention
propose to call the "Northumberland and Durham" type of steam boiler.
I
According to my invention the flue has formed in it, at intervals along its length,
two or more "mid-feathers" crossing at opposite angles and open at each end to the
water in the boiler. Each of these "mid-feathers," which I propose to make of
oblong shape in the lengthway of the flue with semi-circular ends, has in it a number
of tubes between its flat sides, through the inside of which tubes the flame and gases
from the furnace pass, their outside surfaces being surrounded by the water. In
order to cause the flame and gases to traverse the length of the fluc in a serpentine
or spiral direction, and to pass alternately over and under the "mid-feathers" and
through the small tubes, I provide "baffle" bridges which will preferably be of fire
brick on each of the "mid-feathers." Thus the flame and gases from the furnace will,
for instance, first impinge upon the upper portion of the flue surface to the first
"mid-feather," at the end of which they are diverted by the "baffle" bridge and
caused to pass through the small tubes, now traversing and impinging upon the lower
portion of the fue surface, till they are again diverted by the "baffle" bridge at the
second "mid-feather" and caused to pass through the small tubes and so on to the
end of the flue.
1
The advantages I anticipate are:
Greatly increased evaporation from the additional heating surface afforded by the
"mid-feathers" and the small fire tubes passing through them, with consequent
economy from the more complete absorption of their heat before the flame and gases
leave the flue.
Increased strength of the flue against collapse by the support given to it by the
"mid-feathers."
More uniform distribution of the flame and gases inside the flue, whereby the upper
and lower portions of its surface will become equally heated when getting up steam,
preventing "arching" or hogging" of the flue the main cause of leakage of
boilers by straining the joints and starting the rivets and better circulation of the
water.
$
Accessibility for cleaning and repairs.
I do not anticipate that any strengthening rings or hoops will be required with
flues constructed as I have described and longitudinal seams may be avoided by
welding the flue plates at the intervals between the "mid-feathers" which will be
readily effected. The "mid-feathers
I propose preferably to weld up and flange
their ends to the circle of inside of flue and the fire tubes may be expanded in their
holes like ordinary boiler tubes and if necessary some of them may form stay tubes.
Dated this 20th dor of Noh 1889

page_text: COMPLETE SPECIFICATION.
Improvements in the Internal Flues of Steam Boilers.
I, ERNEST RICHARD JOICEY, of No. 8 St. Edmund Place and Beverley Boiler
Works East Street Gateshead in the County of Durham Engineer and Boiler Maker
do hereby declare the nature of said invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement :-
In
My invention specially relates to improvements in the construction of the internal
flues of boilers having one or more flues and boilers made according to my invention
I propose to call the "Northumberland and Durham "
type of steam boilers.
According to my invention the flue has formed in it at intervals along its length two
or more mid-feathers" crossing at opposite angles and open at each end to the water
in the boiler. Each of these mid-feathers," which I propose to make of oblong
shape in the lengthway of the flue with semi circular ends, has in it a number of
tubes between its flat sides, through the inside of which tubes the flume and gases
from the furnace pass, their outside surfaces being surrounded by the water.
order to cause the flame and gases to traverse the length of the flue in a serpentine
or spiral direction, and to pass alternately over and under the "mid-feathers and
through the small tubes, I provide "baffle-bridges" which will preferably be of fire
brick on each of the "mid-feathers." Thus the flame and gases from the furnace will,
for instance, first impinge against the upper portion of the flue surface, to the first
mid-feather, at the end of which it is diverted by the "baffle" bridge and caused to
pass through the small tubes now traversing and impinging upon the lower portion of
the flue surface, till they are again diverted by the baffle" bridge at the second
mid-feather and caused to pass through the small tubes and so on to the end of the
flue.
The advantages I anticipate are:
"
Greatly increased evaporation from the additional heating surface afforded by the
mid-feathers and the small fire tubes passing through them with consequent economy
from the more complete absorption of their heat before the flames and gases leave the
Alue.
Increased strength of the flue against collapse by the support given to it by the
"mid-feathers."
More uniform distribution of the flame and gases inside the flue whereby the upper
and lower portions of its surface will become equally heated when getting up steam
preventing "arching" or "hogging" of the flue (the main cause of leakage of
boiler by straining the joints and starting the rivets) and better circulation of the
water.
Accessibility for cleaning and repairs.
I do not anticipate that any strengthening rings or hoops will be required with
flues constructed as I have described and longitudinal seams may be avoided by
welding the flue plates at the intervals between the mid-feather which will be readily
effected.
The midfeathers I propose preferably to weld up and flange their ends to the
diameter of inside of flue and the fire tubes may be flanged and rivetted or expanded
in their holes like ordinary boiler tubes when small tubes are used and if necessary
some of them may form stay tubes.
244
DESCRIPTION OF DRAWINGS.
On the accompanying sheet of Drawings
Fig. 1 is an end view in section of a 2 flued boiler each flue being fitted with
3 mid-feathers according to my invention and Fig. 2 is a longitudinal sectional
elevation through the line x-x of Fig. 1.
The mid-feathers M F M F2 and M F³ form water spaces communicating with the
shell of boiler and have their flat sides stayed by fire tubes FT through which the

page_text: flame and hot gases from the furnace F take the direction of the arrows first passing
over the bridge at back of furnace through the fire tubes F Tin midfeathers M F' then
stopped by the baffle bridge B B' and compelled to take a downward direction and pass
upward through the fire tubes in mid-feather M F2 and then compelled by baffle
bridge B B to return down the fire tubes in mid-feather M F and so pass to the flues
of boiler seating.
The fire tubes FT are shewn of large size about 8 ins. diameter and are intended
to be flanged and rivetted to the straight sides of mid-feathers in the manner of
Galloway circulation tubes but where pure water is available I propose to use these
fire tubes of the size of ordinary boiler tubes 3 to 4 ins. dia. and to fix them in the
mid-feather sides by expanding their ends or by screwing them like stay tubes. By
the introduction of the mid-feathers with fire tubes between their flat sides perfect
circulation is secured and a great increase of heating surface in the midfeathers them-
selves but specially from the fire tubes of which a very large number may be used if
of moderate diameters and I anticipate that much smaller Boilers may be used with
equal evaporation results.
As will be seen the spaces between the mid-feathers being of limited extent longi-
tudinal seams in the flues may be avoided these spaces being welded up instead of
being rivetted.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed 1 declare that what I
claim is
The construction of the internal flues of steam boilers with water mid-feathers at
intervals along the length of flue and crossing it in the manner of circulation tubes,
said mid-feathers having, between their flat sides, a number of fire tubes so arranged
that by "baffle-bridges" the flame and gases from the furnace are compelled to take
a serpentine course through the flue and so obviate the injurious effects of the upper
portion of the flue only being traversed by the flamo and gases, as well as to increase
the strength of flues, to improve circulation of water and to give greater evaporative
power by increased heating surface.
A
זבז
T. J. DANSON, F.I.P.A.,
2, St. Nicholas Buildings, Newcastle-on-Tyne, Agent for Applicant.