An Improved Non-explosible Multitubular Boiler.
Year: 1893

page_text: Date of Application, 9th Mar., 1893
Complete Specification Left, 2nd Dec., 1893-Accepted, 6th Jan., 1894
PROVISIONAL SPECIFICATION.
An Improved Non-explosible Multitubular Boiler.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23 Southampton Buildings, in the
County of Middlesex, Patent Agent, do hereby declare the nature of this inven-
tion, (a communication to me from Alphonse Coignet, of 55 Boulevard du Nord,
Lyons, in the Republic of France, Manufacturing Chemist), to be as follows:-
Multitubular boilers known as non-explosible are thus designated because they
contain only a small volume of water, but, however small may be this volume, it is
still sufficient to give rise to serious accidents when a rupture takes place in the
heated parts.
On the other hand the small amount of caloric stored in these boilers renders them
difficult to work when the consumption of steam is irregular.
The boiler constituting the subject of the present invention can, on the contrary,
contain a great volume of water, without presenting the slightest danger in case a
rupture should take place in the heated parts.
These conditions are obtained in the following manner :-
1st. By only exposing to the direct action of the fire the collection of tubes which
has a sufficient extent to provide the necessary surface.
2nd. By dividing the cluster of tubes into small sections and in providing each of
these sections with valves which automatically isolate from the rest of the boiler,
any section in which a rupture has just taken place.
The accompanying drawing represents one kind of boiler fulfilling these
conditions.
Figure 1. is a longitudinal section through one of the clusters of tubes.
Figure 2 is a half transverse section on the line 1. 2 of Figure 1 and
Figure 3 is a front elevation.
The body of the boiler is composed of two horizontal boilers A. and placed one
above the other, joined at the front end by a large vertical tube D, which assures
the descending circulation; these boilers extend longitudinally in the centre of the
boiler between the two clusters of tubes. Behind these are the collectors C. C. C' C¹;
on which are branched the tubular elements, these collectors are fixed perpendicu-
larly to each side of the boilers A and B.
The tubular clusters are formed by independent elements in the form of a
serpentine, uniting the lower and upper collectors, each element being composed of
two vertical rows of tubes a. a. b. b. inclined in opposite directions and joined two
and two to each end by the communication boxes e. e the lower and upper tubes are
joined to the collectors by the bent joints d. d.
These serpentines being fixed only at the back expand freely in front and can
also be of great length, they are supported at various parts by the partitions E E
in which they can slide two other partitions F F, placed at the ends protect the
communication boxes from the action of the fire.
The grate G is placed in front, and the hot gases circulate around the par-
titions E. E as indicated by the arrows, before they arrive at the chimney H. The
heating chambers are closed laterally by the walls I. I which enclose the clusters"
of tubes.
In this manner the boilers and the collectors are completely outside the passage
of the heated gases and consequently shielded from all accidents. One could how-
ever without diminishing the security give to the hot gases a last circuit in the.
central chamber M in contact with the boilers A and B.

page_text: One could also install in this chamber serpentines serving as feed water heaters
or steam superheaters.
The vertical serpentines which compose the tubular cluster are the only parts
directly heated, they are furnished at their two ends with valves s. s. opening in the
interior of the collectors C. C¹.
These valves close on seats placed at the end of the tubes d. d and when working
normally, they are kept open by springs or counterweights. Figure 4 shows the
form of one of them drawn to a larger scale.
From this arrangement it results that as soon as a rent is made in one of the
serpentines, and there lowers the pressure, the two valves are closed and isolate
the affected serpentine without the boiler ceasing to work.
This accident only entails the emptying of the water contained in the serpentine
and allows of waiting for a favorable opportunity to change the damaged tube or
tubes.
In the case where the serpentines have only a small volume, one can do away
with the multiplicity of the valves, by uniting several serpentines or even all the
tubular cluster, by means of collectors of small diameter which are themselves
connected to the bodies of the boiler.
The valves would be placed at the extremities of these collectors and in case of
accident would isolate either the affected section or the entire tubular cluster.
In this latter case the working would be interrupted but the boiler would not be
emptied.
I, BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings, in the
County of London Patent Agent do hereby declare the nature of this invention,
a communication to me from Alphonse Coignet of 55 Boulevard du Nord, Lyons
in the Republic of France, Manufacturing Chemist, and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement :-
Multitubular boilers known as non-explosible are thus designated because they
contain only a small volume of water, but however small may be this volume, it
is still sufficient to give rise to serious accidents when a rupture takes place in the
heated parts.
On the other hand the small amount of caloric stored in these boilers renders
them difficult to work when the consumption of steam is irregular.
The boiler constituting the subject of the present invention can on the contrary
contain a great volume of water without presenting the slightest danger in case a
rupture should take place in the heated parts.
These conditions are obtained in the following manner :-
1st. By only exposing to the direct action of the fire the collection of tubes
which has a sufficient extent to provide the necessary surface.
2nd. By dividing the cluster of tubes into small sections and in providing each
of these sections with valves which automatically isolate from the rest of the
boiler, any section in which a rupture has taken place.
The drawing accompanying my Provisional Specification represents one kind of
boiler fulfilling these conditions.
Figure 1 is a longitudinal section through one of the clusters of tubes.

page_text: Figure 2 is a half transverse section on the line 1. 2 of Figure 1 and
Figure 3 is a front elevation.
The body of the boiler is composed of two horizontal boilers A and B placed
one above the other, joined at the front end by a large vertical tube D, which
ensures the descending circulation; these boilers extend longitudinally in the
centre of the boiler between the two clusters of tubes. Behind these are the
collectors C. C. C¹ C¹; on which are branched the tubular elements, these collectors
are fixed perpendicularly to each side of the boilers A and B.
The tubular clusters are formed by independent elements in the form of a
serpentine, uniting the lower and upper collectors, each element being composed
of two vertical rows of tubes a. a b. b inclined in opposite directions and joined
two and two to each end by the communication boxes e. e the lower and upper tubes
are joined to the collectors by the bent joints d. d.
These serpentines being fixed only at the back expand freely in front and can
also be of great length, they are supported at various parts by the partitions E E
in which they can slide two other partitions F F, placed at the ends protect the
communication boxes from the action of the fire.
The grate G is placed in front, and the hot gases circulate around the par-
titions E E as indicated by the arrows, before they arrive at the chimney H.
The heating chambers are closed laterally by the walls II which enclose the
clusters of tubes.
In this manner the boilers and the collectors are completely outside the passage
of the heated gases and consequently shielded from all accidents. One could
however without diminishing the security give to the hot gases a last circuit in the
central chamber M in contact with the boilers A and B.
Serpentines serving as feed water heaters or steam superheaters could also be
arranged in this chamber.
The vertical serpentines which compose the tubular cluster are the only parts
directly heated they are furnished at their two ends with valves S. S. opening into
the interior of the collectors C. C¹.
These valves close on seats placed at the end of the tubes d. d and when working
normally they are kept open by springs or counterweights. Figure 4 shows the
form of one of them drawn to a larger scale.
From this arrangement it results that as soon as a rent is made in one of the
serpentines, and there lowers the pressure, the two valves are closed and isolate
the affected serpentine without the boiler ceasing to work.
This accident only entails the emptying of the water contained in the serpentine
and allows of waiting for a favorable opportunity to change the damaged tube or
tubes.
In the case where the serpentines have only a small volume, one can do away
with the multiplicity of the valves, by uniting several serpentines or even all the
tubular cluster, by means of collectors of small diameter which are themselves
connected to the bodies of the boiler.
The valves would be placed at the extremities of these collectors and in case of
accident would isolate either the affected section or the entire tubular cluster. In
this latter case the working would be interrupted but the boiler would not be
emptied.
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. A multitubular boiler composed of independent serpentines uniting two
superposed boiler bodies or collectors in which the tubes only are directly heated
and each serpentine is furnished with two valves opening into the interior of the
collectors and closing automatically as soon as a rupture takes place in this serpen-
tine so as to isolate it from the rest of the boiler substantially as herein shown and
described.

page_text: 2. A multitubular boiler as above described and in which the serpentines are
united all together or in sections by means of collectors of small diameter, furnished
with valves opening into the interior of the boiler bodies and closing automatically
as soon as a rupture takes place so as to isolate from the rest of the boiler the
section where the accident has occured that is to say the whole cluster of tubes,
substantially as herein shown and described.
Dated this 2nd day of December 1893.
B. J. B. MILLS,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.