IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS IN ORDER TO RENDER THEM MORE SAFE
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MOSES
POOLE, of Lincoln's Inn, in the County of Middlesex, Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
fminster, the Eleventh day of September, in the third year of Her reign, did,
or Herself, Her heirs and successors, give and grant unto me, the said Moses
Poole, Her especial licence, full power, sole privilege and authority, that I,
the said Moses Poole, my exors, admors, and assigns, or such others as I,
the said Moses Poole, my exors, adñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, the
Invention of "IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS IN
ORDER TO RENDER THEM MORE SAFE," communicated to me by a certain Foreigner
residing abroad; in which said Letters Patent is contained a proviso, that I
the said Moses Poole, shall cause a particular description of the nature of the
said Invention, and in what manner the same is to be performed, to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Moses Poole, do hereby declare the nature of the said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked thercon,
that is to say:-
The Invention relates-First, to a mode of applying thin surfaces to be
burst by any material encrease of pressure of steam in the boiler, and in such
manner that other such surfaces may be readily replaced without the boiler
being put out of work by the bursting of a surface, thus offering a means
of safety for the escape of steam which can be at all times depended on.
Secondly, to a mode of applying a whistle to steam boilers in order to indicate
when the water is below the proper working line. And in order to give the
best information in respect to the Invention in my power, I will proceed to
describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWING.
The Drawing represents a portion of a steam boiler with the improvements
applied thereto, the apparatus being in section, in order to the same being
readily understood. a is an opening in the steam boiler at which the apparatus
is applied. is a tube or way through which the steam can pass; as indicated
by the Drawing. c is an enlarged end of the tube b, and it is in this part of
the apparatus where what I call the bursting or safety plate or surface is
applied. d is the bursting or safety plate which is pressed on by the ring e,
such ring having a bell mouth in order to prevent the edges cutting the burst-
ing or safety plate when pressed on from below. f is a ring with a flange
which screws into the upper part of the end of the tube or way b, and by such
means secures the safety or bursting plate in its place; the surface on which
the plate d rests being formed with an elevated ring or surface over which the
plate d is bent, in order that the holding around the edges may be the more
secure. g is a padlock by which the flanges of the ring f and tlie upper end of
the tube b can be secured, and thus prevent any person removing the safety
plate or surface d unless with a key to open the lock. I would remark, that
although the above mode of apparatus for affixing the plate d in its place is
very convenient and simple, I do not confine myself thereto, as the mode of
aflixing the plate in its place may be varied without departing from the Inven-
tion. h is a cock, the plug of which is also capable of being locked and
secured, as is shown in the Drawing. The end of the tube is filled with
water, and both under and over the plate d, the object of which is to keep the
plated at an equable temperature. In working with this apparatus, in the

page_text: event of the steam getting higher than the pressure it is determined (above
the working pressure of steam) the plato d will burst and permit the steam to
flow off, and thereby reduces the excess of pressure in the boiler, and the plate
may be then replaced without stopping the working of the boiler for the purpose
of the engine, and the replacing of the burst plate by another is performed by
shutting the cock h, and removing the bursted plate by unscrewing the rings
which retain it in the end of the tube or way b, and then placing a fresh, plate
d. I have called the whole of the apparatus a tube b, because when combined
together the parts in fact make one continuous bent tube or way, and the
nature of the parts being clearly shown in the Drawing, no further description
thereof will be necessary, and the construction thereof, may be varied. It
should, however, be remarked that is important that the opening at 6', 6',
should on the one hand be sufficiently large to relieve the boiler of the excess
of pressure when the bursting takes place, and yet not be so large as to cause
so powerful an explosion as to be injurious to the boiler; and it has been
found desirable in carrying out this Invention to observe the French rule
directed by the Royal Ordnance, the twenty-ninth day of October, One thou-
sand eight hundred and twenty-three, of making the size of the opening in
proportion to the heating surface of the boiler, which is as follows: Having
measured every portion of the boiler which in any way can be called, heating
surface, the proper size of opening is obtained in the following manner:
Engineers in the habit of making calculations will easily obtain the required
diameter of an opening for a particular area of heated surface by the following

page_text: NOTE. It should be stated that the above table is formed as if the bursting
was into a vacuum, but as there is the atmosphere at all times external of a
steam boiler, the table, in fact, commences with a working pressure of half an
atmosphere. It will be evident, that if the diameter of a given thickness of
plate be encreased it will burst at a lower pressure of steam, and the diameter
be decreased it will require a greater pressure to burst it, consequently by a
few trials the thickness and diameter may be obtained for any degree of pres-
sure desired. It should be stated that the steam way or tube 6 should at all
times be as large as the opening b', 6', but preferably somewhat larger. In
using the above described apparatus, it may be employed separately as a means
of safety or conjointly with any of the ordinary safety valves, and in using it
with other safety valves the common safety valve should be so weighted as to
allow of being lifted and admit of the passage off of steam at a pressure a little
less than would burst the plate d.
I will now proceed to describe the second part of the Invention. At an
opening in the boiler is affixed a whistle, such as is shown at m, having a plug
n to fit the opening, the plug being in direct communication with and attached
to a float, such float it is preferred should be of light wood encased in copper.
o, o, is a framing which serves to keep the rod and plug n upright and correct
to its work. p, p, are weights. It will be evident that so long as the water is
up to its proper working line the plug will be closed; but if the water sinks
the plug will descend, and the rush of steam through the whistle will indicate
the want of water, and the noise will cease so soon as the proper water line is
again attained.
Having thus described the nature of the Invention and the manner in which
the same is to be performed, I would have it understood that what I claim is,
first, the mode of applying bursting or safety plates or surfaces as herein
described; and secondly, I claim the mode of applying a float to work a whistle
as herein described. ⚫ :
In witness whereof, I, the said Moses Poole, have hereunto set my hand
and seal, this Eleventh day of March, in the year of our Lord One
thousand eight hundred and forty.
MOSES (L.s.) POOLE.

page_text: AND BE IT REMEMBERED, that on the Eleventh day of March, in the
year of our Lord 1840, the aforesaid Moses Poole came before our said Lady
the Queen in Her Chancery, and acknowledged the Specification aforesaid, and
all and every thing therein contained and specified, in form above written.
And also the Specification aforesaid was stamped according to the tenor of
the Statute made for that purpose.
Inrolled the Eleventh day of March, in the year of our Lord One
thousand eight hundred and forty.