A New or Improved Device for Automatically Effecting the Closure of Tubes or Passages of Water-tube Steam Boilers (or analogous Tubes or Passages Subjected to the Action of Fluids Under Pressure) on the Occurrence of Rupture therein.
Year: 1894

page_text: Date of Application, 25th Aug., 1894
Complete Specification Left, 23rd May, 1895-Accepted, 13th July, 1895
PROVISIONAL SPECIFICATION.
A New or Improved Device for Automatically Effecting the Closure
of Tubes or Passages of Water-tube Steam Boilers (or analogous
Tubes or Passages Subjected to the Action of Fluids Under
Pressure) on the Occurrence of Rupture therein.
I, HENRY MATHESON of 1 Castelnau Cottages, Castelnau, Barnes, in the
County of Surrey Gentleman do hereby declare the nature of my invention to be
as follows:-
The object of my invention is to provide means whereby on the occurrence of
rupture in the tubes or passages of water tube steam boilers or analogous tubes or
passages under the pressure of fluids the said tubes or passages are automatically
closed and the outlet of steam water or other fluid therefrom prevented. According
to my invention I apply to the tube or passage a device which when the tube or
passage is unruptured is maintained by the equality. of pressure on all its sides in
a position or form such that it does not obstruct the way through the tube or
passage but which when rupture occurs, owing to the inequality of pressure which
then arises is caused to close the tube or passage so ruptured. The device may
conveniently consist of a tubular end of thin metal inserted in the end of the tube
or passage and so shaped that when relief of pressure occurs in the tube or passage
owing to the rupture thereof the greater pressure on the outer sides of the tubular
end causes it to be closed in in such a way as to completely shut off the interior of
the tube or passage from the steam or fluid in the boiler or vessel. The invention
is not limited to this particular form of the device as it may be arranged in
any other convenient way provided that it is such as to be maintained open during
normal work of the tube or passage but to close under the action of differential
pressure on the occurrence of a rupture in the tube or passage.
Dystha the 4th dan of A1804
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, W.C., Agents.
COMPLETE SPECIFICATION.
A New or Improved Device for Automatically Effecting the Closure
of Tubes or Passages of Water-tube Steam Boilers (or analogous
Tubes or Passages Subjected to the Action of Fluids Under
Pressure) on the Occurrence of Rupture therein.
I, HENRY MATHESON of 1 Castelnau Cottages, Castelnau, Barnes in the
County of Surrey, Gentleman, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
The object of my invention is to provide means whereby on the occurrence of
rupture in the tubes or passages of water-tube steam boiler or analogous tubes or

page_text: passages under, the pressure of fluids, the said tubes or passages are automatically
closed and the outlet of steam, water, or other fluid, therefrom prevented.
Several attempts have I believe been made to effect this by valves, spheres, and
the like, but they have not answered in practice owing to their complication and the
expensive fitting required and to their liability to displacement, corrosion and
injury and also to the obstruction they present to the free passage to and through
the tubes or passages to be protected.
According to my invention I apply to the tube or passage a device as herein-
after more particularly described, which when the tube or passage is unruptured is
maintained by the equality of pressure on all its sides in a position or form such
that it does not obstruct the way through the tube or passage, but which. when
rupture occurs owing to the inequality of pressure which then arises, is caused to
close the way through the tube or passage so ruptured. The device is arranged so
that it is equivalent to a portion or prolongation of the tube or passage itself and
(as nearly as convenient) of the same internal diameter and may conveniently
consist of a tubular end of thin metal (or other suitable material which will with-
stand the action of the vapour or liquid and temperature and pressure to which it is
exposed) inserted in the end of the tube or passage and so shaped that when relief
of pressure occurs in the tube or passage owing to rupture thereof the greater
pressure on the outer sides of the tubular end causes it to be closed in, in such a
way as to completely shut off the interior of the tube or passage from the steam
or fluid in the boiler or vessel so that the said steam or fluid does not escape
through the said tube or passage.
Figure 1 of the accompanying drawing represents a device made according to
my invention and Figure 2 shews it applied to a tube B in a tube plate A. It is
shewn of a stout tube C encircled by and having projecting from it a thinner
tube D which is shaped as shewn for example in cross sections in Figures 3, 4
and 5 or in other equivalent manner, so that excess of pressure at its outer side
over that on its inner side will at once close it. The tubes C and D are inserted
in the tube B and expanded therein so that they are held tightly, the inner ends of
the said tubes C and D preferably resting on a shoulder a short distance within the
tube B as shewn. The tube C, should project beyond the end of the tube B, to an
extent equal to say from about the length of its own diameter to three or four times
the diameter of the tube or passage B, according to the sensitiveness required.
The device should be stouter at its base (that is the part of it inserted in the tube
or passage B) than it is at its other extremity so that it is very sensitive to:
variations of pressure any inrush of steam or fluid causing it to automatically close
by the pressure forcing in the sides so that they meet. It may also be made more
sensitive by cutting a short slit in each side of the thin end. The internal pressure
thus being relieved the full crushing or external pressure of the steam or fluid on
the external surface of the tube D, would force or blow out the plug thus formed
were it not that the tube C is of sufficient thickness and strength to resist this.
In constructing this safety device it will be found more convenient and economical
in practice to make it of one thinness throughout and to strengthen the base to
nearly half its length by an internal ring of stouter material as shown but the
device may be made in one piece thinner at its outer than at its inner end and
this difference in strength or thickness may be gradual if preferred.
As the object of the thin and weak portion of the device is to give the initial
closure not only metal but any other suitable material than metal may be used for
this purpose (especially so in the case of corrosive fluids or vapours) provided
that they are of such a nature as not to be disintegrated by high or low temperatures
a suitable substance for instance is Rhode's asbestos rubber.
I may fix the safety device to the tube or passage to be protected either
internally or externally, but preferably 1 insert the tube C, or the thick end of
the device into the tube or passage to a depth sufficient to hold it securely in
its place. This is most conveniently done by first countersinking or easing out the
tubes or passages at their ends so that when the device is in its place, the inside

page_text: diameter thereof corresponds as nearly as possible with the inside diameter of
the tube B or other passage. It may be conveniently secured in place by expanding
or rolling in.
When in its place the weak or collapsing property of the thin extremity of the
device may be considerably increased by shaping that part of it to a form least
able to resist external pressure as shewn in Figures 3 and 4 for example. These
shapes may be varied according to the requirements of the tubes or passages to be
protected, and may be formed by driving with a smart tap into the tube D a
tool so shaped that when withdrawn it will leave the said tube of the flattened
or other form desired.
The invention is not limited to the particular forms of the device shewn in the
drawings as it may be arranged in any other convenient way provided that it is
such as to be maintained open during normal work of the tube or passage without
obstructing the passage therethrough but to close under the action of differential
pressure on the occurrence of a rupture in the tube or passage substantially as
hereinbefore explained.
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. For the purpose described a device forming virtually the end of the tube or
passage to be protected and so arranged and shaped that when pressure on its
inner side is relieved excess of pressure on its outer side will close it in and
so obstruct the way through the tube or passage substantially as hereinbefore
described.
2. A safety device for the purpose set forth, the said device being made
substantially as hereinbefore described and shewn in the accompanying drawings.
Dated this 23rd day of May 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.