IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM BOILERS
Year: 1839

page_text: ADA
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
ROBERT ABRAHAM, of Keppell Street, in the Parish of Saint George Blooms-
bury, and County of Middlesex, Civil Engineer and Architect, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Third day of January, in the second year of Her reign, and
in the year of our Lord One thousand eight hundred and thirty-nine, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Henry Robert Abraham, my exors, adñiors, and assigns, or such others as
I, the said Henry Robert Abraham, my exors, adññiors, 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 mentioned, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, and also in all Her Majesty's Colonies and Plantations
abroad, my Invention of "IMPROVEMENTS IN APPARATUS APPLICABLE TO STEAM
BOILERS;" in which said Letters Patent is contained a proviso obliging me,
the said Henry Robert Abraham, by an instrument in writing under my hand
and seal, particularly to describe and ascertain the nature of my said Inven-
tion, and in what manner the same is to be performed, and cause the same.
to be inrolled in Her 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.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Henry Robert Abraham, do hereby declare that the nature of my said Inven-

page_text: tion, and the manner in which the same is to be performed, is particularly
described and ascertained in and by the following description thereof, reference
being had to the Drawings hereunto annexed, and to the letters and figures
marked thereon (that is to say):-
My improvements in apparatus applicable to steam boilers relates,―
First, to improved construction of safety valves, whereby I am enabled to
improve their action, and render them more certain and rapaid in their opera-
tion than those now in use.
And, secondly, my Invention relates to a mechanical arrangement of a valve
for the purpose of warning an engineer or attendant upon a boiler when the
supply of water is deficient.
The several letters of reference in the accompanying Drawings indicate
similar parts in each view of the same object.
No. 1 is a safety valve sustained by a mercurial column, the operation of
which may be affected either by the use of the parts delineated in this Figure,
or secondly, by those of No. 2, in which; in place of the cylinder and piston
used in No. 1, metal discs connected by a dilatable steam-tight band D are
substituted. The material I use for the band is canvas, prepared with india
rubber, but I do not confine myself thereto. And, thirdly, in the use of a
boiler in which steam of a very bigh pressure is not generated, the metal
weight floating in mercury, as in No. 3. The action of the apparatus, Nos. 1
and 2, may be described as follows:-The safety valve A is attached to a rod
fixed to a piston or disc F, and is upheld in its seat by a column of mercury in
the tube B, communicating with the cylinder or chamber E, and sustaining
the mercury-tight piston or disc F. This column of mercury is limited in
height to the power of steam which may be safely generated in the boiler,
making allowance for friction. The valve, cylinder, piston, and other parts
surrounding, are suspended in a lantern frame within the boiler, and the valve
is opened in both cases when the steam in the boiler overcomes the pressure of
the mercury and the friction. The mercury pressed out of the cylinder is
discharged into a covered receiver G, outside the boiler. The piston F having
a greater superfices than the valve, requires a preponderating force when the
pressure of steam is raised above that of the column, of mercury acting against
it, and is therefore depressed with force proportionate, to the difference in area
between the valve and piston, and the force of the steam exceeding that of the
column of mercury, less the friction. The valve being thus opened, and the
piston depressed, the mercury is forced into the shallow receiver G, and remains
there until the boiler is sufficiently relieved, when the column again prepon-
derating raises the piston and closes the valve., In order to, avoid the necessity

page_text: of using a higher column of mercury against high-pressure steam, as well as to
relieve the piston from great pressure, it may be well to adop the lever
weights H, H, as indicated by dotted lines, to retain the valve in its seat,
and to use the column of mercury to raise it after the excess of pressure of
steam has depressed the piston. The fulcrum of each lever H, is at H'.. By
the addition of a lever to the spindle O the motion of this valve may be reversed,
and made to open externally, and the power may be increased or diminished
according to the arrangement of the arms of the lever. The column of
mercury should be so arranged that when the steam is at working pressure the
valve may be slightly opened; no sticking will then occur. The action
of the valve Number 3 differs in principle from the foregoing, inasmuch as
the weight M, connected with the valve A, is substituted for the tight piston,
and opens the valve by the action of gravity when the supporting mercury is
depressed below the line of flotation by an excessive.pressure of steam over the
column in the tube and cylinder. It differs also from the action of the com-
mon valve, that in the latter the weight is applied to shut the valve, and the
steam to open it. The reverse is the case in this construction, as the weight
opens the valve and the steam shuts it. In this apparatus a shallow vessel is
formed round the top of the cylinder within the boiler to receive the mercury
depressed previous to the generation of steam. The weight M must have
sufficient gravity to open the valve against the pressure of steam when the
sustaining mercury has been depressed, and so adjusted that the line of flotation
shall correspond nearly with that of the height of the column of mercury in the
tube B when the steam is at the maximum pressure, and at the height of this
line of pressure the receiver G outside when boiler is fixed; when the pressure
of steam is raised above this limit the mercury is propelled into the receiver G,
and the weight M opens the valve. The valve is closed by the steam acting
against its under side, and by the floating of the weight M. The weight may
be of lead, in an iron case, or of iron, or any suitable material not acted
upon by mercury. By substituting an air vessel for the receiver G, this valve
may be worked at a higher pressure.
I would remark, that I do not confine myself to the precise forms herein
described, and delineated in the Drawing annexed.
But what I claim, as the first part of my Invention, are, the modes of
constructing and applying safety-valves, as herein described.......
I will now proceed to describe my Invention so far as it relates to the warning
valve to detect an insufficiency of water in the boiler. The arrangement of
parts is such that the warning valve is worked by the rod of a float by means
of an eccentric or bent lever, or other contrivance suitable to give the motion

page_text: required, connected with a spindle rod of the valve, the fulcrum being attached
to the boiler plate or flange of the pipe by screws or otherwise before the valve
seat, and the spindle having either a slot or notches for the lever to work in.
The float is hung in the boiler, so that it may be immersed in water until the
supply is deficient; its gravity (which is to be sufficient to overcome the pres-
sure of steam on the valve) will then cause it to descend, when the valve will
be opened by the eccentric or lever of the rod, and allow the steam to
escape through the whistle until a proper supply is given. In the accom-
panying Drawing, A is the valve; B, the pipe communicating with the whistle
of an ordinary construction; C, the spindle of the valve; D, D, guides; E, the
eccentric of the rod of the float; F, a small friction roller; G, the fulcrum ;
H, the float.
I would have it understood that I am aware that various arrangements of
warning valves have before been applied to boilers; I do not therefore claim
the same when not arranged according to my mode.
And I claim, as this part of my Invention, the mode of working a warning
valve by means of the gravity of the float, as above described.
In witness whereof, I, the said Henry Robert Abraham, have hereunto
set my hand and seal, this Second day of July, in the year of our
Lord One thousand eight hundred and thirty-nine.