AN IMPROVED SAFETY VALVE FOR STEAM BOILERS
Year: 1866

page_text: LETTERS PATENT to Henry Hackett, of Warrington, in the County of
Lancaster, Mechanical Engineer, for the Invention of "AN IMPROVED
SAFETY VALVE FOR STEAM BOILERS."
Sealed the 31st August 1866, and dated the 5th March 1866.
PROVISIONAL SPECIFICATION left by the said Henry Hackett at the
Office of the Commissioners of Patents, with his Petition, on the
5th March 1866.
I, HENRY HACKETT, of Warrington, in the County of Lancaster, Mechanical
Engineer, do hereby declare the nature of the said Invention for "AN.
IMPROVED SAFETY VALVE FOR STEAM BOILERS," to be as follows:-
My Invention relates to a novel construction and arrangement of safety
valve which is designed to prevent explosions in steam boilers from over
pressure of steam, and is particularly applicable in checking any increase in
the pressure when there is a deficiency of water in the boiler. The improved
apparatus termed a safety valve consists of an internal cylinder enclosed and
surrounded by an outer cylinder, the two being cast together and secured by

page_text: a flange to the top of the boiler, the space between the two cylinders forming
an annular space or chamber; the outer casing or cylinder projects somewhat
bigher than the internal cylinder, but is so arranged that a valve can be
inserted so as to cover the internal cylinder and annular space, the whole
being covered in by a lid, space being allowed for the valve to rise and fall;
the valve can be weighted internally or by any of the well-known means now
adapted. The peculiar arrangement of cylinder described allows both the
pressure of water and steam to act upon the valve in the manner and for the
purpose herein-after described. The internal cylinder being open to the
boiler allows the pressure of steam to act upon the valve, and the annular
space being connected by induction pipes with the water allows the pressure
of the same to be exerted in conjunction with the steam upon the under side of
the same valve; an outlet in the outer cylinder on a line with the valve
seating is connected by a tube with the furnace, thus when the pressure in the
boiler exceeds the weight of the valve the steam acting upon the valve up the
internal and the water upon the same valve up the annular space causes such
valve to rise and expose the opening communicating with the furnace through
which the water and steam rushes, and is conducted so as to impinge against
the crown of the flue and fall in a shower upon the fire, thereby extinguishing
the same. The same effect is produced upon the valve for extinguishing the
fire at any pressure if there should be a deficiency of water in the boiler; this
is accomplished by extending the lever employed for weighting or "loading"
the valve some distance beyond its fulcrum; to the end of this lever a vertical
rod is suspended, to the lower end of which, below the water line, a bucket or
hollow vessel is secured; this vessel, when there is sufficient water in the
boiler, being of the same specific gravity as the water, remain submerged at
any depth required, or to which it has been adjusted upon the vertical rod; for
example, say, the vessel is so arranged and adjusted that its bottom is two to
three inches from the crown of the flue, so long as there is plenty of water in
the boiler it remains in that position without exerting any weight upon the
lever from which it is suspended, but should the water get below the vessel
the water which it contains then acts as a counterbalance to the weight with
which the valve is loaded, thereby causing the slightest pressure in the
boiler to raise such valve, which immediately causes a reduction of the pressure
as described.
"

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Hackett in. the, Great Seal Patent Office on the
5th September 1866.
3
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
HACKETT, of Warrington, in the County of Lancaster, Mechanical Engineer,
send greeting.
:
J
*
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of March, in the year of our Lord One
thousand eight hundred and sixty-six, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Hackett, Her special license that I, the said, Henry Hackett,
my, executors, administrators, and assigns, or such others as I, the said:
Henry Hackett, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED
SAFETY. VALVE FOR STEAM BOILERS," upon the condition (amongst others) that I,
the said Henry Hackett, my executors or administrators, by an instrument
in writing under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Henry Hackett, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings (that is to say)
==
My Invention relates to a novel construction and arrangement of a safety
valve which is designed to prevent explosions in steam boilers from over
pressure of steam, and is particularly applicable in checking any increase in
the pressure when there is any deficiency of water in the boiler. The
improved apparatus termed a safety valve consists of an internal cylinder
enclosed and surrounded by an outer cylinder, the two being cast together and
secured by a flange to the top of the boiler, the space between the two
cylinders forming an annular hollow ring or cavity. The outer casing or
cylinder projects somewhat higher than the internal cylinder, but is so
arranged that a valve can be inserted so as to cover the internal cylinder and

page_text: annular space, the whole being covered in by a lid, space being allowed for
the valve to rise and fall, the said valve can be, weighted internally or by any
of the well-known means now adopted. The peculiar arrangement and
combination of cylinders described allows both the pressure of water and
steam to act upon the valve in the manner and for the purpose herein-after
described. The internal cylinder being open to the boiler allows the pressure
of steam to act upon the valve, and the annular space being connected by
induction pipes with the water allows the pressure of the same to be exerted
in conjunction with the steam upon the same valve. An outlet in the outer
cylinder on a line with the valve seating is connected by a tube with the
furnace, thus when the pressure in the boiler exceeds the weight on the valve
the steam acting on the valve up the internal cylinder and the water on the
same valve up: the annular space causes such valve to rise and expose the
opening communicating with the furnace through which the water and steam
rush and is conducted so as to impinge against the crown of the flue and fall
in a shower upon the fire, thereby extinguishing the same. The same raising
of the valve is produced for extinguishing the fire at any pressure if there
should be a deficiency of water in the boiler; this is accomplished by
extending from a fulcrum underneath the fulcrum of the ordinary lever a
second lever having a projection beyond such fulcrum towards the weight of
the top lever. To the extreme end of this second under lever on the opposite
side of its fulcrum a weight or float is attached that will rise and fall with the
water in the boiler, thus if the water should become dangerously low the
short end of the lever on the opposite side of the fulcrum from the float is
brought into contact with the lever by which the valve is loaded, which has
the effect of lifting such lever with a power proportionate to the weight of the
float, which acting as a counterbalance to the weight wherewith the valve is
loaded relieves such valve, so that the slightest pressure will raise it and
allow the water to be ejected therefrom as berein-before described for the
purpose of extinguishing the fire.
In order that the Invention may be more clearly understood and explained
in detail I have hereunto attached a Sheet of Drawing made on a scale of
about one inch and a half to the foot, similar letters of reference being marked
thereupon.
B
.
Fig. 1 represents a longitudinal section of an ordinary boiler having the
valve applied thereto. This view shews the arrangement and disposition of
the levers in connection with the float for extinguishing the fire at low water,
also the tube or pipe by which the water is conducted and showered on to the
fire; Fig. 2 represents a transverse section of the boiler and valve.

page_text: In Figs. 1 and 2, a, a, is the boiler; b, the flue; c, the furnace; and d, the
bridge, all being well-known parts of the boiler. At any convenient place on
the boiler the valve V is placed, the form and construction of which may be
thus described; e is the outer casing or cylinder of the valve; f; the inner
cylinder. The annular space 9 formed by these two cylinders is connected by
the induction pipes h, h, with the water of the boiler. The internal lift
valve i is constructed so as to fit the bore of the internal cylinder f, the cap k
of which is formed so as completely to cover the annular space 9, the whole
being closed in by the lid or cover l. This valve i is loaded in the ordinary
manner by the lever m and weight k. Thus when the pressure in the boiler
exceeds the load upon the valve it is raised from its seating, which im-"
mediately causes the water from the boiler to rush from the annular space of
the valve down the conducting pipe n, so as to impinge against the crown of the
furnace, from whence it is showered on to the fire, which has the effect of
reducing the fire and of checking and diminishing the pressure in the boiler,
after the accomplishment of which the valve once more closes upon its seating,
preventing thereby any further discharge of water from the boiler. The same
effect upon the valve is obtained by the lever or float p for reducing and
extinguishing the furnace in order to prevent explosion or damage to the
boiler when the water gets low in the following manner:-The float p is
connected to the end of the longest arm of the lever o; this lever has its
fulcrum a little distance below the fulcrum of the lever m. The end of the
short arm of the lever o on the opposite side of its fulcrum from the float is
slightly turned up, having a recess or V formed therein that will easily clip or
fit on the under side of the lever m. Thus when there is sufficient water in
the boiler the lever o being governed by its float freely moves up and down,
but should the water get below water line the recess in the end of the short
arm of the lever o comes into contact with the lever m. The pressure or
force of such contact increasing with any reduction of water that now takes
place, so that when the water is approaching a dangerously low point the
weight loading the valve is counterbalanced, allowing thereby a copious
discharge of water to be injected upon the fire in the manner and for the
purpose herein-before described.
Having now described the nature of my said Invention, together with the
method of carrying the same into practical effect, I wish it to be distinctly
understood that I claim,-
First, the novel construction and arrangement of valve herein-before
described as applied to steam boilers for the purpose of checking an excessive
pressure, and also for determining the pressure such boilers shall carry.

page_text: And, secondly, I claim the arrangement and construction of apparatus in
connection with my improved valve for preventing damage or explosion when
there is a deficiency of water in the boiler, together with the application,
arrangement, and construction, or any slight modification of the various parts,
so long as the principal features of the Invention are retained.
In witness whereof, I, the said Henry Hackett, have hereunto set my
hand and seal, this Third day of September, in the year of our Lord
One thousand eight hundred and sixty-six.
HENRY HACKETT. (L.s.)