An Improved Float for Low-water Safety-valves.
Year: 1891

page_text: Date of Application, 18th Aug., 1891
Complete Specification Left, 14.h May, 1892-Accepted, 18th June, 1892
PROVISIONAL SPECIFICATION.
An Improved Float for Low-water Safety-valves.
We, JOHN ADDY HOPKINSON and JOSEPH HOPKINSON of the firm of
J. Hopkinson & Co. Huddersfield, in the County of York, Engineers, do hereby
declare the nature of this invention to be as follows:-
Our invention relates to safety valves for steam boilers, and more particularly to
the floats of low water safety valves of the kind or class well known as Hopkinson's
safety valves.
Heretofore the floats of such valves have been made of earthenware or the like,
but this material becomes in course of time deteriorated by the action of the boiling
water under pressure, and by the compositions that are used in boilers, and is
gradually washed away, thereby impairing the efficiency of the valve, and in some
cases rendering the valve inoperative.
The float cannot be made of a solid block of iron without increasing the cost and
weight of the parts of the valve, and if it is made in the form of a hollow iron box
there is considerable risk of leakage and filling of the same with water, in which
case the efficiency of the valve would be impaired.
Now the object of our invention is to construct a float which shall have the
required buoyancy and weight to operate the valve effectually without being
unnecessarily heavy, and which will be substantially non-absorbent, and capable of
resisting the action of the water, steam pressure, temperature, boiler compositions,
and other deteriorating influences that exist or are. likely to exist in a boiler
working at high pressure.
According to one mode of carrying our invention into effect, we provide a metal,
preferably iron, tray and constructed in two parts to admit of being passed into the
boiler through the manhole. The said tray is constructed with the requisite bolt
holes for bolting the same together and with a hole for the float rod.
We fill the said tray with finely ground coke, soot, or other suitable form of
carbon which has been previously prepared with rubber and sulphur to form
a composition capable of being cemented and consolidated into a solid mass by
vulcanizing the said rubber mixed therewith. We may vulcanize the composition,
by any of the well known methods and preferably we conduct the vulcanising
operation in situ. We sometimes incorporate pitch with the rubber and vulcanising
materials. The cementation effected by the vulcanising to which the mixture
is subjected not only cements the material together but chemically changes the
rubber and produces a composition which is insoluble in boiling water even under
high pressure.
The said composition is practically non-absorbent, and it will
effectually resist the action of temperature and pressure. The said composition,
moreover, is capable of resisting the action of acids and alkalies and all the
deteriorating influences in the boiler, and fulfils all the conditions required in
a float.
We may dispense with the metal tray and form the composition into the desired
shape by moulding, but we prefer to employ a tray as affording the most practical
mode of constructing our improved float.
Dated this 18th day of August 1891
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicants.

page_text: An improved Float for Low-war Malovy-vALTON,
We, JOHN ADLY HOPKINSON and JOSEPH HOPKINSON, of the firm of
J. Hopkinson & Co., Huddersfield, in the County of York, Engineers, 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 :-
.
Our invention relates to an improved float for low-water safety valves of the kind
or class well known as Hopkinson's safety valves.
Heretofore the floats of such valves have been made of earthenware or the like,
but this material becomes in course of time deteriorated by the action of the boiling
water under pressure, and by the compositions that are used in boilers, and is
gradually washed away, thereby impairing the efficiency of the valve, and in some
cases rendering the valve inoperative.
The float cannot be made of a solid block of iron without increasing the cost and
weight of the parts of the valve, and if it is made in the form of a hollow iron box
there is considerable risk of leakage and filling of the same with water, in which
case the efficiency of the valve would be impaired.
. Now the object of our invention is to construct a float which shall have the
required buoyancy and weight to operate the valve effectually without being
unnecessarily heavy, and which will be substantially nonabsorbent, and capable of
resisting the action of the water, steam pressure, temperature, boiler composition,
and other deteriorating influences that exist or are likely to exist in a boiler
working at high pressure.
According to one node of carrying our invention into effect, we provide a metal,
preferably iron, tray constructed in two parts to admit of being passed into the
boiler through the manhole. The said tray is constructed with the requisite bolt
holes for bolting the same together, and with a hole for the float rod.
We fill the said tray with finely ground coke, soot or other suitable form of
carbon, or oxide of iron or other suitable material, which has been previously
prepared with rubber and sulphur to form a composition capable of being cemented
and consolidated into a solid mass by vulcanizing the said rubber mixed therewith.
We may vulcanize the composition by any of the well known methods, and prefer-
ably we conduct the vulcanizing operation in situ. We sometimes incorporate
pitch with the rubber and vulcanizing materials. The cementation effected by the
vulcanizing to which the mixture is subjected not only cements the material
together but chemically changes the rubber and produces a composition which is
insoluble in boiling water even under high pressure. The said composition is
substantially non-absorbent, and it will effectually resist the action of temperature
and pressure. The said composition, moreover, is capable of resisting the action of
acids and alkalies and all the deteriorating influences in the boiler, and fulfils all the
conditions required in a float.
Instead of a tray we may employ a frame to hold the composition, or we may
dispense with the tray and form the composition into the desired shape by moulding,
but we prefer to employ a tray as affording the most practical mode of constructing
our improved float.
We may provide the tray with an iron cover. In some cases we coat the
surface of the contents of the tray with rubber and sulphur prepared for
vulcanization and we vulcanize the said coating by any of the well known methods.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A float constructed of the materials and in the manner substantially as herein
described, for the purpose specified.
Dated this 14th day of May 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.