IMPROVEMENTS IN MULTITUBULAR STEAM BOILERS
Year: 1884

page_text: I FRANCIS SANDERS MORRIS of Middleton Lodge, Tottenham in the county of
Middlesex, Engineer do hereby declare the nature of the said invention for
"IMPROVEMENTS IN MULTITUBULAR STEAM BOILERS" to be as follows:-
This invention relates to improvements in multitubular steam boilers of all kinds
the improvements having for object to provide an increased and more efficient
heating surface than hitherto whereby steam is more rapidly generated and at
a less expense of fuel than by the ordinary construction of boiler. At the same
time a boiler constructed according to my invention is practically free from the
risk of explosion arising from shortness of water.
My invention consists in combining tubes known as "Field " tubes with fire
tubes, by inserting such "Field " tubes within the fire tubes.
In carrying out my invention the fire tubes are of sufficient area to allow of an
annular space being left between and around the "Field " tubes. The "Field"
tubes hang pendently from a tube plate which plate forms the top of a chamber
which I propose to call the secondary combustion chamber. From the bottom
plate of this chamber are suspended the fire tubes, their lower ends being expanded
into the bottom tube plate which forms the top of the ordinary or primary com-
bustion chamber or fire box. The "Field " tubes are regulated in length by the
fire tubes, being continued in length till they are flush with the bottom tube plate
and their extremities conjointly with the orifices of the fire tubes are immediately
above the furnace and directly exposed to the action of the flames.
The products of combustion being conducted through the annular space around
the "Field " tubes become thoroughly and substantially divided and well utilized
before they reach the secondary combustion chamber and finally pass out from the
boiler through an uptake connected with this upper chamber. I dish the tube plate
forming the top of the primary combustion chamber or fire box and into which as
above stated are expanded the lower ends of the fire tubes; the convexity of the
plate will be towards the interior of the water space; by this means the deposition
of extraneous matter in the "pockets" is greatly facilitated and will so prevent
the accumulation of scale and incrustation around and between the tubos.

page_text: *. In some cases I find it advantageous to employ a larger central firo tube without
"Field" tube and having if required a baffle. This central tube facilitates the
clearing of the secondary combustion chamber.
I have described my invention as applied to a vertical boiler. In the case of
horizontal boilers I propose to combine my arrangement with the ordinary
horizontal boiler in which case the products of combustion having passed through
the ordinary horizontal fire tubes will pass into a chamber between the ends of the
horizontal tubes and the lower ends of my arrangement of vertical tubes.
0012
1001

page_text: Improvements in Multitubular Steam Boilers.
"
I FRANCIS SANDERS MORRIS of Middleton Lodge, Tottenham, in the county of
Middlesex, Engineer do hereby declare the nature of the said invention for
"IMPROVEMENTS IN MULTITUBULAR STEAM BOILERS and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
This invention relates to improvements in multitubular steam boilers the
improvements having for object to provide an increased and more efficient heating
surface than hitherto whereby steam is more rapidly generated and at a less
expense of fuel than by the ordinary construction of boiler.
My invention consists in combining tubes known as "Field " tubes or analogous
tubes with fire tubes, by inserting such "Field" or analogous tubes within the fire
tubes.
In carrying out my invention the fire tubes are of sufficient area to allow of an
annular space being left between and around the "Field " tubes. The "Field"
tubes hang pendently from a tube plate which plate forms the top of a chamber
which I propose to call the secondary combustion chamber. In the bottom plate
of this chamber are fixed the fire tubes their lower ends being expanded into the
bottom tube plate which forms the top of the ordinary or primary combustion
chamber or fire box. The "Field " tubes are regulated in length by the fire tubes,
being continued in length till they are flush with the bottom tube plate or they
may extend below the fire tubes and their extremities conjointly with the orifices
of the fire tubes are mostly immediately above the furnace and directly exposed to
the action of the flames.
The products of combustion being conducted through the annular spaces around
the "Field" or analogous tubes become thoroughly and substantially divided and
well utilized before they reach the secondary combustion chamber and finally pass
out from the boiler through an uptake connected with this upper chamber. I some-
times dish the tube plate forming the top of the primary combustion chamber or
fire box and into which as above stated are expanded the lower ends of the fire
tubes; the convexity of the plate will be towards the interior of the water space ;
by this means the deposition of extraneous matter in the "pockets" is greatly
facilitated and will so prevent the accumulation of scale and incrustation around
and between the tubes but I do not in all cases so dish the tube plate.
In some cases I find it advantageous to employ a large central fire tube without
a"Field" tube and having if required a battle. This central tube facilitates the
clearing of the secondary combustion chamber and assists in regulating the
draught.
In order to enable my invention to be fully understood I will proceed to describe
the same by reference to the accompanying drawing in which figure 1 represents
a vertical section of a vertical multitubular steam boiler constructed according to
my invention and in which all the "Field " tubes are shown of uniform length
and having their lower ends level with the extremities of the fire tubes; the boiler
is shewn provided with a large central fire tube; figure 2 is a vertical section

page_text: drawn to a larger scale of one of the combined Field "and fire tubes shewing
also a portion of the top and bottom plates of the secondary combustion chamber
and top plate of the fire box; figure 3 is a horizontal section on line A, B of
figure 2. Figure 4 is a section of a vertical boiler having a central water tube
and "Field "tubes of unequal lengths, some of the latter projecting downwards
beyond the bottoms of the fire tubes; figure 5, is a horizontal section on line C, D,
of figure 4.
Similar letters in all the figures represent similar or corresponding parts.
Referring to figure 1, a, represents the shell of the boiler which shell is of
ordinary construction; b, b (figures 1, 2 and 3) are the fire tubes; c, c, are the
circulating tubes placed within water tubes d, d, the said tubes c and d, together
forming what are known as "Field " tubes which are inserted within the fire
tubes b, as clearly shewn in figures 2 and 3; e, e, are the spaces left around the
"Field" tubes c, d, and between the same and the fire tubes b; f,f, are the usual
water spaces between the tubes c, and d; g, is the tube plate from which the
"Field" tubes c, d, are pendently hung and h, is the chamber which I call the
secondary. combustion chamber of which the tube plate g, forms the top; i, is
the bottom plate of the chamber h, from which plate i, are suspended the firo
tubes bj, is the bottom tube plate which forms the top of the ordinary or primary
combustion chamber or fire box k, and into which are expanded the lower ends of
the fire tubes b; in this arrangement the lower ends of the "Field" tubes c, d,
are shewn level with those of the fire tubes b, which latter are flush or nearly so
with the bottom tube plate j, they are in fact expanded into the said plate in the
ordinary manner; 2, is the large central fire tube leading from the fire box k, to
the secondary combustion chamber h; m, is the baffle in the fire tube l, which
baffle m, can be operated by means of a rod n, so as to raise and lower the same
for the purpose of regulating the draught through the fire tubes b; o, is the uptake
for conveying the products of combustion from the chamber h, out of the boiler.
I have here shewn the tube plate j, (forming the top of the primary combustion
chamber or fire box) dished, the convexity being towards the interior of the water
space as shewn.
By placing the water tubes d, entirely within the fire tubes as herein before
described and shewn in figure 1, they will be protected from the results of careless
stoking as the risk of the water tubes becoming loosened through being struck is
entirely obviated; this I consider in some cases to be an important improvement
on an ordinary hanging water tube boiler.
The products of combustion formed in the primary combustion chamber k, are
conducted through the annular spaces e, around the water tubes d, in the direction
shewn by the arrows in figure 2 and become thereby thoroughly and substantially
divided and well utilized before they reach the secondary combustion chamber h,
whence they pass through the uptake o, and out of the boiler; the circulation of
the water in the "Field" tubes c, d takes place in the usual manner, that is to say,
from the inside of the shell a, of the boiler down through the tubes c, and then up
through the tubes d, in the direction shewn by the arrows in figure 2.
The secondary combustion chamber h, is of great importance with a sharp
draught and when burning certain kinds of fuel; as the escaping volatile portions
of the fuel become re-ignited upon reaching this chamber h which thereby becomes
most efficient heating surface.
In the boiler shewn in figures 4 and 5 the arrangement of the "Field " tubes
and fire tubes is substantially the same as that hereinbefore described when referring
to figures 1, 2 and 3, but I have shewn the boiler provided with a centre water
tube p, to facilitate circulation from the underside of the upper fire tube plate i
The steam formed around the fire tubes b, and under the fire tube plate i, is thereby
assisted in escaping, thus materially aiding the general circulation of the water in
the boiler; the boiler is also provided with small "Field " tubes and fire tubes as
shewn to allow of sufficient space being left between the larger tubes as the space
occupied by the insertion of the central or auxiliary water tube prevents a sufficient

page_text: number of tubes of equal diameter being advantageously arranged in the tube
plates; a¹, a¹, a¹, a¹, are stay tubes for staying the upper and lower fire tubo
plates, i and j; in addition to the stay tubes a I also employ the usual stays 6¹
connecting the tube plate g with the top of the boiler. I consider it advantageous
to employ the stay tubes a¹, inasmuch as it is dangerous to allow the tube plates i,
and j, to depend entirely for their support on the ordinary fire tubes as the tubes
in time become worn away; o, represents the uptake which by reason of the central
water tube p, being employed is placed at the side of and outside the boiler instead
of passing through the centre thereof as in figure 1; for the purpose of equalizing
the distribution of the heat I sometimes employ two of such uptakes.o, communi-
cating with the chamber h, one placed at each side of the boiler; q, is a door to
allow of cleaning out the chamber h; r, r, are hand holes for cleaning out other
parts of the boiler; the bottom tube plate j, is shewn flat instead of being dished
as in figure 1, and the larger "Field "tubes c, d, are shown slightly extended below
the bottom ends of the fire tubes b.
The lower ends of the "Field " tubes c, d, and fire tubes b,-are as will be seen by
referring to figures 1 and 4 of the drawing, immediately above the furnace k, and
will therefore be directly exposed to the action of the flames.
It will be observed that ample provision is made for thoroughly cleaning my
improved boilers from scale and other extraneous matter common to all classes of
boilers.
Amongst the many advantages to be derived from the use of boilers constructed
according to my invention the following may be mentioned as those of primary
importance; a great economy is effected in the consumption of fuel owing to the
increased and more efficient heating surface; my improved arrangement of tubes
admits of a considerable reduction in the size of a boiler as compared with those
of ordinary construction.
Whilst retaining all the valuable features of a "Field" or analogous pendent
water tube I produce a greater efficiency as regards the localization and concen-
tration of the products of combustion around the "Field" or analogous water
tubes and at the same time I utilize heat not previously employed to raise steam
in ordinary water tube boilers by transmitting the said heat to the water around
the fire tubes.
The objection often experienced in boilers having pendent water tubes videlicet,
the liability of the tubes becoming loose can be obviated by my arrangement of
shrouding the said water tubes.
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
1. Combining tubes known as "Field " tubes (or analogous tubes) with ordinary
fire tubes by inserting such "Field" or analogous tubes within the fire tubes of
multitubular steam boilers substantially as and for the purposes hereinbefore
described and represented in the accompanying drawing.
2. The improved multitubular steam boilers herein before described and repre-
sented in the various figures of the accompanying drawing.