IMPROVEMENTS IN the CONSTRUCTION OF SAFETY VALVES
Year: 1873

page_text: LETTERS PATENT to Samuel Hallam, of West Gorton, near the City
of Manchester, Engineer, for the Invention of "IMPROVEMENTS IN the
CONSTRUCTION OF SAFETY VALVES."
Sealed the 20th October 1873, and dated the 30th August 1873.
PROVISIONAL SPECIFICATION left by the said Samuel Hallam at
the Office of the Commissioners of Patents, with his Petition, on
the 30th August 1873.
w
I, SAMUEL HALLAM, of West Gorton, near the City of Manchester,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF SAFETY VALVES," to be as follows:-
The object of this Invention is to facilitate the escape of the steam,
and thereby to prevent the pressure in the boiler increasing beyond
the desired limit.
In performing my Invention I use an annular valve fitting on each
side of an annular opening in the seating. A circular chamber surrounds
the seating to cause the steam in escaping outwards to act on a flange
L

page_text: projecting from the valve, while the stoam escaping inwards acts on the
interior of the valve. The pressure on the valve is obtained by spring or
weight applied direct or or through levers.
My Invention may be modified in the form of a compound valve, that
is to say, an annular valve fitting on a seating, and the upper part 5
whereof forms a seating for a second valve. The two valves are
connected by rods and links to two levers, one of which is weighted.
In constructing safety valves for marine boilers I obtain the pressure
by a spring, one end of which is fixed in the valve spindle, and the other
in an adjustable stud, the spindle and stud being connected together by 10
a pin passing through a slot in the spindle, the object of which is to
limit the lift of the valve in case the spring should break.
The above details may be modified by varying the shape of the
flanges on which the steam acts in escaping externally and internally.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Samuel Hallam in the Great Seal Patent Office
on the 28th February 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
HALLAM, of West Gorton, near the City of Manchester, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of August, in the year of our Lord
One thousand eight hundred and seventy-three, in the thirty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Samuel Hallam, Her special licence that I, the said
Samuel Hallam, my executors, administrators, and assigns, or such
others as I, the said Samuel Hallam, 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 THE CONSTRUCTION OF
SAFETY VALVES," upon the condition (amongst others) that I, the said

page_text: Samuel Hallam, 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 Office within six calendar months next.
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Samuel Hallam, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement (that is to say) :-
The object of this Invention is to facilitate the escape of the steam,.
and thereby to prevent the pressure in the boiler incréasing beyond the.
desired limit.
In performing my Invention I use an annular valve fitting on each
side of an annular opening in the seating. A circular chamber surrounds
the seating to guide the steam' in escaping outwards, while the steam
escaping inwards acts on the interior of the valve. The pressure on the
valve is obtained by spring or weight applied direct or through levers.
In constructing safety valves for marine, locomotive, or portable
boilers I obtain the pressure by a spring, one end of which is fixed in
the valve spindle, and the other in an adjustable stud.
My Invention may be modified in the form of a compound valve, that
is to say, an annular valve fitting on a scating, and the upper part
whereof forms a seating for a second valve. The two valves are connected
by rods and links to two levers, one of which is weighted.
The above details may be modified.

page_text: pipe a. In this bush is formed the annular seating for the valve o,
which fits on each side of the seating. The valve is formed with four
arms connected to the centre boss, and in the centre boss of the annular
seating is screwed a stud d, which passes through the boss of the valve,
and the upper end of the stud is screwed into the cup e, containing the
light spring f. The requisite pressure is applied to the valve by the
weights g fitting on the bush h the centre boss of which is connected
to the outer bush by four wings, as shewn in Fig. 3, and this centre
boss is provided with a block h¹ fitting on the hemispherical head of the
valve c.
When the pressure on the steam exceeds the weights and the
light spring the valve o rises off its seating, and the steam escapes both
outwardly and inwardly, as shewn by the arrows in Fig. 1. The steam
escaping outwardly is guided upwards by the circular chamber surround-
ing the seating b, and then escapés through the open end of the bush h.
The steam that escapes inwardly is also guided to the open end of the
bush 7, as shewn by the arrows. When the steam has escaped until it
regains its working prossure the spring fassists in bringing the valve c
down on to its seating.
Fig. 4 represents another of my improved safety valves. The parts
marked a, b, and c, are very similar to those shewn and described in
reference to Fig. 1. In this case the valve is weighted by the weighted
lever i, and the stud d fits below in the centre of the valve c, and above
it is forked for the lever i to bear upon. The lever i is guided in the
bridlej, to which is screwed the cup 1, containing the light spring k, and
When the valve has
this spring acts on the lever i by the spindle 1.
been raised by the steam the resistance of the weight and of the spring k
has to be overcome, and as soon as the steam has blown off to the
required extent the spring / assists the weight suspended to the lever i
to bring the valve down on to its seating.
Fig. 5 represents another of my improved safety valves; and Fig. 6, a
horizontal section of the same. The parts marked a, b, are in this case
cast together, and the parts marked c and d are similar to those shewn
in Fig. 1; but the valve c is provided with a flange c¹ and a bush c²,
containing the lower end of the spring m, by which the valve is held
down. The upper end of this spring abuts against the under isde of the
cap n, which is held down by the nut n¹, the stud n³ locking the cap and
nut together. When the pressure of steam exceeds the resistance of the

page_text: spring m the valve rises, and the steam escapes in the direction shewn by
the arrows.
Figs. 7 and 8 are two views, partly in section, of one of my improved
double safety valves, particularly adapted for marine, locomotive, or
portable boilers. The casing of this double valve is united to a singe
flange, so that only one perforation is required in the shell of the boiler.
The parts marked a, b, c, and c¹, are similar to those shewn in. Fig. 5.
In this case the spindle d of the valve passes downwards through the
valve c, through the valve seating and casing a, b, and the lower end fits
in the adjustable socket d, the valve being connected to the spindle by a
key and steel plate. The pressure on the valve is obtained by the
spring m, one end of which is secured to the spindle d, and the other end
to the socket . The tension of the spring can be regulated by the
nut n', which is locked by the stud n³, as before described.
In case of the spring breaking the valve could not be blown away,
owing to the end of the spring coming in contact with the under side of
the casing a.
On Sheet 2 Fig. 9 is a sectional elevation of my improved compound
safety valve; Fig. 10 is a plan in section of the lower valve; and
Fig. 11 is the upper valve. The case or elbow pipe a is fixed to the
boiler or other vessel containing steam, and in this case is fixed the
seating b, which is provided with an annular recess, as before described.
c is the valve fitting on the seating 6, and weighted by the rod d
and weighted lever p, which is hinged to the fulcrum p². The upper
face of the valve c forms an annular seating for the upper valve o, which
is weighted by the lever i and stud o³, the lever i being connected to the
lever p, by the link p'. When the steam rises sufficiently to lift the
valve c the valve o is also raised, but to a greater extent, owing to the
difference in the leverage, and the steam then escapes both outwardly
and internally through both the valves, as shewn by the arrows.
Having thus stated the nature of my Invention, and described several
modes of performing the same, I wish it to be understood that I do not
intend to limit myself to the details given, as the same may be varied or
modified, and I claim,-
First. The general combination and arrangement of the parts consti-
tuting the improved safety valves, shewn and described.

page_text: Secondly. The improved mode of constructing the annular safety
valves, as shewn and described.
Thirdly. The application of a circular chamber above the seating, as
shewn and described.
Fourthly.. The application of a light spring to assist in bringing the
valve down on to its face, as Shewn and described.
Fifthly. The improved mode of locking the valve when the tension of
the weighting spring has been determined, as shewn and described.
And, lastly. The improved compound safety valve shewn and described
in reference to Sheet 2.
In witness whereof, I, the said Samuel Hallam, have hereto set
my hand and seal, this Twenty-sixth day of February, One thousand
eight hundred and seventy-four.
SAMITEL ALTAM
SAMITEL TATTAM
(1.5.)