IMPROVEMENTS IN SAFETY AND RELIEF VALVES
Year: 1872

page_text: LETTERS PATENT to John Bullough, of No. 152, York Road, Lambeth,
in the County of Surrey, for the Invention of "IMPROVEMENTS IN
SAFETY AND RELIEF VALVES."
Scaled the 24th June 1873, and dated the 31st December 1872.
PROVISIONAL SPECIFICATION left by the said John Bullough at the
Office of the Commissioners of Patents, with his Petition, on the
31st December 1872.
I, JOHN BULLOUGH, of No. 152, York Road, Lambeth, in the County
of Surrey, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN SAFETY AND RELIEF VALVES,” to be as follows :—
"
This Invention relates to the construction and arrangement of safety
and relief valves in such a manner that only a moderate load of weight
or spring is required to keep the valve closed against considerable pressure,
and that when the valve opens, a large area of escape is provided for the
pressing fluid. For this purpose I unite two valves on one stem, the one
valve having an area somewhat larger than the other, and I arrange
these valves in a valve box or casing with passages in such a manner
that the fluid pressure tending to open the larger valve tends to keep
the smaller valve closed. I load the valves or their stem either directly

page_text: or by a lever with a weight or spring sufficient to balance the desired
pressure acting on the difference of the two valve areas. In this
manner the load required may be reduced to a very small amount, as it
has to balance only the difference of pressure on the two valves, while
the opening presented for escape of fluid when the load is overcome is
equivalent to the sum of the areas of the two valvos.
Valves constructed and arranged as above described, may be applied
as safety valves to boilers or other vessels containing fluid under
pressure, or as relief valves to cylinders or other vessels subject to
occasional excess of pressure.
]
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Bullough in the Great. Seal Patent Office
on the 25th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BULLOUGH, of No. 152, York Road, Lambeth, in the County of Surrey,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of December, in the
year of our Lord One thousand cight hundred and seventy-two, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Bullough,
Her special license that I, the said John Bullough, my execu-
tors, administrators, and assigns, or such others as I, the said John
Bullough, 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 "IMPROVEMENTS IN SAFETY AND RELIEF VALVES," upon the
condition (amongst others) that I, the said John Bullough, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, 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
-

page_text: Office within six calendar months next and immediately after the date
of the said Letters Patent.
.
NOW KNOW YE,. that I, the said John Bullough, 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 thereof, reference being had to the
accompanying Sheet of Drawings, and to the figures and lotters marked
thereon, that is to say :—
This Invention relates to the construction and arrangement of safety
and relief valves in such a manner that only a moderate load of weight
or spring is required to keep the valve closed against considersable
pressure, and that when the valve opens a large area of escape is
provided for the pressing fluid. For this purpose I unite two valves on
one stem, the one valve having an area somewhat larger than the other,
and I arrange these valves in a valve box or casing with passages in such
a manner that the fluid pressure tending to open the larger valve tends
to keep the smaller valve closed. I load the valves or their stem either
directly or by a lever with a weight or spring sufficient to balance the
desired pressure acting on the difference of the two valve areas. In this
manner the load required may be reduced to a very small amount, as it
has to balance only the difference of pressure on the two valves, while
the opening presented for escape of fluid when the load is overcome is
equivalent to the sum of the areas of the two valves.
Valves constructed and arranged as above described, may be applied
as safety valves to boilers or other vessels containing fluid under
pressure, or as relief valves to cylinders or other vessels, subject to
occasional excess of pressure.
DESAD IDHYAY An THE DR A TETNO

page_text: cavity above the upper valve B. The valves may be held to their seats by
a spring E, compressed between the lower valve A and a screw collar F,
which can be introduced into the valve case by opening the back of the
casing, and screwed down between two projecting ribs H, H, on which a
screw thread is cut to adjust the pressure. Instead of employing a spring
as shewn, a weight might be suspended from the valve within the boiler,
or the stem of the valve might be extended upwards through a stuffing
box in the cover K, and a weight or spring made to act either directly
or with leverage upon this stem.
For convenience of raising the valves from their seats, a rocking
shaft L is mounted within the casing, having arms which come under a
collar on the valve stem or on a box M which contains the lower part of
the spring. By applying a wrench to the projecting squared end of the
shaft L, the valves can be lifted, or the pressure of the spring eased off
them, so that they will be lifted by a very small amount of fluid
pressure.
It will be seen that the load required to keep the valves seated has to
be adjusted only to the pressure on the difference of the areas of
A and B, but when the valves lift, escape is provided equivalent to the
sum of the two areas opened..
Having thus described the nature of my Invention and in what
manner the same is to be performed, I claim the use for a safety or relief
valve of two valves of different areas united to one stem, and arranged so
that the pressure acts to open the larger and close the smaller valve,
whereby the load required to keep the valves closed is that due to the
pressure on the difference of their areas, while the passage offered for
escape of fluid when the valves are open is equivalent to the sum of the
areas of opening, substantially as herein described.
In witness whereof, I, the said John Bullough, have hereunto
set my hand and scal, this Twentieth day of June, in the year
..
Land One thousand night hundund and savanter thro
JOHN BULLOUGH. (L.S.)