IMPROVEMENTS IN STEAM BOILERS APPLICABLE FOR MARINE USE AND OTHER PURPOSES
Year: 1885

page_text: I ISAAO PIMBLOT of Northwich in the county of Chester Boiler maker do hereby
declare the nature of my said invention for "IMPROVEMENTS IN STEAM BOILERS
APPLICABLE FOR MARINE USE AND OTHER PURPOSES" to be as follows
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The object of this invention is to provide a steam boiler or generator in which
there shall be good circulation, that shall have large grate and heating surface
and that shall admit of the flues and tubes being easily removed for repair and
replaced.
It consists of an ordinary shell preferably with longitudinal tubes from back to
front through which the products of combustion return, of a simple furnace and flue
preferably with double furnace fronts and doors and "Galloway" tubes of crescent
or similar shape
In carrying out the invention the boiler is constructed with a single large furnace
extending nearly across it, leading into a flue of similar construction The shape of
the furnace is preferably that of two cylinders joined together with the plates
which would abut, removed, somewhat resembling two ordinary flues opening into
each other at the sides. The flues and furnace are stayed and strengthened with
tubes of the "Galloway" type but of special construction which form a very
important part of my invention.
I have found that if ordinary vertical round water tubes be used, the great
draught in marine boilers forces the flame and products of combustion through
so fast that comparatively little heat is given out. To obviate this, I form my
tubes in section the shape of a crescent with its ends rounded, the concavity of the
crescent facing the draught by having several rows of these tubes breaking joint
or arranged diagonally, the draught impinges in the hollows of the first row, and
escaping at the rounded cusps strikes the centre of the concavities of the next row,
at the same time heating the backs of the first row and so on. The crescent
shaped tubes are preferably tapered in their length to facilitate the fixing of them.
By the time that the products of combustion reach the combustion chamber they
have parted with much of their heat. The combustion chamber has a semi circular
bottom and well stayed top, and from this, tubes in the ordinary manner proceed
back to the smoke box. The furnace bars are of any ordinary type except where
[Price 8d

page_text: they are interfered with by the tubes At these latter points they are preferably
cast several together the outer one only going the whole length, the others (filling
the broken space) being shaped to suit
The flue and furnace of the boiler are made tapering towards the back with a
flange at each end by means of which they are secured in position The taper is
sufficient to allow of inner or back flange being made sufficiently small to enter
through the opening in the front of the boiler and the front flange is attached to
the boiler front externally By this arrangement the flue may be easily removed
or replaced without interfering with the main structure of the boiler, the rivets
securing the outer or front flange can be cut similarly to those securing the inner
or back flange, and the flue withdrawn from the front of the boiler
After repair
it can be replaced, or if worn out, a new one can be substituted
In action, as soon as the furnace fire is well lighted the flame and products of
combustion, heating the water tubes establish an upward current through the
water tubes and among the return tubes at top through which the products of
combustion pass, in this way the cooler water at the bottom is continually rising
up to the heating surface, hotter water taking its place, and thus all parts of the
boiler are well heated and the strains due to unequal expansion reduced to a
minimum
This invention with slight modification is applicable for nearly all stationary as
well as marine steam boilers where large internal flues are used.

page_text: other Purposes.
I, ISAAC PIMBLOTT of Northwich in the county of Chester, Boiler maker do
hereby declare the nature of this invention and in what manner the same 18
to be performed, to be particularly described and ascertained in and by the
following statement
-
The object of this invention is to provide a steam boiler or generator in which
there shall be good circulation, that shall have large grate and heating surface,
and that shall admit of the flues and tubes being easily removed for repair and
replaced
It is best described by aid of the accompanying drawing in which Figure 1 is a
longitudinal sectional elevation of boiler constructed in accordance with my
invention, Figure 2 sectional plan with parts of tubes B broken away Figure 3
front elevation with smoke "box removed. Figure 4 section showing detail of
construction of flue,
In these A is the shell of the boiler, B upper longitudinal tubes C single large
furnace with two doors D, D, but preferably separated into two chambers by a pair
of "Galloway" tubes E, E, with or without a half brick wall between them, or in
place of this the ordinary two cylindrical flues can be used and a water diaphragm
with stayed parallel or curved sides The shape of the furnace is preferably that
of two cylinders joined together with the plates which would abut removed, some-
what resembling two ordinary flues opening into each other at the sides as shown
The flues and furnace are stayed and strengthened with tubes of the " 'Galloway'
type E, E, but in the flues of special construction which form a very important part
of my invention, the furnace vertical tubes can also be of the improved shape
instead of round.
"
I have found that if ordinary vertical round water tubes be used, the great
draught especially in marine boilers forces the flame and products of combustion
through so fast that comparatively little heat is given out. To obviate this, I form
my tubes G, G, in section the shape of a crescent with its ends rounded, the
concavity of the crescent facing the draught. By having several rows of these
tubes breaking joint as shown or arranged diagonally, the draught impinges in the
hollows of the first row, and escaping at the rounded cusps strikes the centre of
the concavities of the next row, at the same time heating the backs of the first row
and so on
The crescent shaped tubes are preferably tapered in their length to
facilitate the fixing of them Where the pressure is very great they can be
strengthened by a row of screwed and rivetted stays along the centre line of the
concavity joining the same to the centre line of convexity By the time that the
products of combustion reach the combustion chamber H, they have parted with
much of their heat The combustion chamber has a semi-circular bottom I and
well stayed top J, and from this, tubes in the ordinary manner proceed back to
the smoke box. The furnace bars are of any ordinary type except where they
are interfered with by the tubes. At these latter points they are preferably cast

page_text: several together, the outer one only going the whole length, the others (filling the
broken space) being shaped to suit
The flue and furnace of the boiler are made tapering towards the back with a
flange at each end by means of which they are secured in position The taper 18
sufficient to allow of inner or back flange being made sufficiently small to enter
through the opening in the front of the boiler and the front flange is attached to
the boiler front externally By this arrangement the flue may be easily removed
or replaced without interfering with the main structure of the boiler, the rivets
securing the outer or front flange can be cut similarly to those securing the inner
or back flange, and the flue withdrawn from the front of the boiler
After repair
it can be replaced, or if worn out, a new one can be substituted
In action, as soon as the furnace fire is well lighted the flame and products of
combustion heating the water tubes establish an upward current through the water
tubes, and among the return tubes at top through which the products of com-
bustion pass, in this way the cooler water at the bottom is continually rising up
to the heating surface, hotter water taking its place, and thus all parts of the
boiler are well heated, and the strains due to unequal expansion reduced to a
minimum
This invention with slight modification is applicable for nearly all stationary as
well as marine steam boilers where large internal flues are used.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to bo performed, I declaro that
what I claim 19 —
1st The manufacture of boilers constructed and arranged substantially as
herein described no part being here claimed separately, but only when combined
with the others to form a complete boiler, substantially as described
2nd. The water tubes formed with a concavity opposed to the draught, and a
convexity the other way, and preferably arranged in such manner as to oblige the
draught to take a winding course, by which means the products of combustion are
obliged to strike the concavity of each tube in succession
DL1000