AN IMPROVED SAFETY-VALVE
Year: 1884

page_text: I, ALBERT SCHMID, Engineer, of Zürich, Switzerland, do hereby declare the
nature of said Invention for AN IMPROVED SAFETY-VALVE, to be as follows :-
My Invention relates to safety valves for steam-boilers and analogous purposes,
and has for its object to avoid or minimise the friction which is an obstacle to the
accurate operation of such valves.
The improved valve comprises a valvo-proper, which is disc-shaped and rests on
the rounded or sharp edge of a cylindrical valve seat, while the top or back of tho
valve is pointed as usual and fits into a socket of a short horizontal lever pivoted
at its other end to the frame of the apparatus. This lever has also a cunicul socket
at the top (vertically over the centre of the valve) into which fits the downward
projecting point in the centre of a disc adapted to receive the pressure of a helical
spring. This spring, the axis of which coincides with the axis of the valve scat,
rests with its lower end on the said disc, and is guided by the same, while the
upper end abuts against and is guided by a corresponding disc held down against
the spring by an adjustable screw passing through the top of the fixed frame or
stand. The base of this frame or stand has the shape of a thick flange secured
to the boiler by a pair of screws, and bored out in the centre to receive the
valve sent, while two diametrically opposite posts extend from the base plate
upward and are joined together above the upper abutment disc of the spring in
order to afford a hold for the adjustable screw mentioned above. The head of this
screw, which projects vertically over the stands, is covered by a cap secured to tho
stand, in order to prevent the unauthorized turning of the same.
One of the vertical posts serves as a pivotal bearing for the lever mentioned
above, which is for this purpose forked so as to enclose the post, and provided on
each side of the fork with a pointed set screw, the point of which fits into a conical
socket of the post.
COMPLETE SPECIFICATION.
I, ALBERT SCHMID, Engineer, of Zürich, Switzerland do hereby declare the
nature of my Invention for AN IMPROVED SAFETY-VALVE and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
My Invention relates to the class of adjustable spring pressed safety valves, and
the object of my Invention is to diminish the amount of friction, and to provide

page_text: a safety valve which will operate with the smallest excess of steam pressure for the
amount for which it is set.
The Invention consists in the construction and arrangement of parts as hereinafter
described and claimed.
Figure 1. shews a vertical section, partly in side elevation, of a safety valve
embodying my Invention; and
Figure 2. is a ground plan of the lower portion, partly in section.
The ring of bronze or other hard metal a forms the seat of the valve b, which
rests freely on the crest of the ring a.
The central pointed head c of the valve b fits into a cavity in the under side of
the forked arm d, the two arms of which are pivoted to one of the side standards f
by means of screws with pivot points that rest in sockets in the side of the
standard. On the upper side of the arm & there is a socket which receives the
central pivot point of the plate h, the same being immediately above the head c of
the valve plate.
The spring g is confined between the two plates h and i, the latter forming a base
block for the regulating screw k and having a central socket which receives the end
of the screw.
The lower plate h has a pin indicated by the dotted lines in Figure 1,
which extends up within the spiral spring almost to the top plate i to limit the
upward movement of the valve.
The pressure on the valve is regulated and set by means of the screw k, and the
head of the same is covered by a cap M to prevent it from being tampered with.
The apparatus is made fast on the boiler by screws and nuts at m and n.
The operation of the safety valve will be readily understood from its construction.
The valve b, being lifted from its seat by the too great pressure of the steam, is
guided in its short ascending motion by the arm d, and, being held by a central
pivot support, is perfectly free to adjust itself to the pressure and any resisting
friction adherence to the seat at any point of its contact surface and to take an
inclined or horizontal position, its point of pressure forming at the time its only
guide.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, 1 declare that what
I claim is:
1. In a safety valve, a pivoted arm in combination with the valve and a spring-
pressed plate between which it is interposed, substantially as and for the purpose
set forth.
2. A safety valve consisting of a valve b having its scat on ring and central
head c, pivoted forked arm d, plate having its central pivot point, spring g, top
plate and regulating screw, combined and arranged substantially as set forth.
Dated this 5th day of September 1884.