NEW OR IMPROVED ARRANGEMENTS OR CONSTRUCTIONS OF STEAM TRAPS
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by George Shann at the Office of
the Commissioners of Patents, with his Petition, on the 6th
February 1875.
I, GEORGE SHANN, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention of "NEW
OR IMPROVED ARRANGEMENTS OR CONSTRUCTIONS OF STEAM TRAPS," to be as
follows, that is to say :-
This Invention relates to new or improved arrangements or construc-
tions of steam traps, and which may be made to act at the same time as
escape or loaded safety valves, to prevent the pressure of steam in the
apparatus to which the trap is attached from rising above a previously
determined limit.
:
The steam trap as constructed under one modification, consists of an
upright chamber or vessel closed at its upper end by an elastic
diaphragm or plate of india-rubber, metal, or other suitable material,
which is so secured in its position as to be steam-tight. At its lower
end the chamber or vessel is closed by a valve, the spindle of which
passes upwards through the chamber and is connected with the

page_text: diaphragm. To either end or other convenient part of the valve spindle,
is attached a weighted lever or suitably arranged spring or combination
of springs, which assist in regulating the action of the valve.
The steam pipes or other apparatus from which the water or con-
densed steam is to be removed communicate with the chamber of the
steam trap by a branch or port placed preferably in the side thereof, and
the weight on the lever or tension or compression of the spring or
springs is so adjusted relatively with the steam pressure, and with
reference to the areas of the valve and diaphragm exposed to that steam
pressure, and also with reference to the weight of the valve itself and its
connexions, that as long as steam only is in the chamber the valve is
held up to its seat, but when a certain amount of water has accumulated
in the chamber the additional load on the valve due to the water above
it causes the valve to open and discharge so much of the water as will
reduce the pressure on the valve sufficient to allow it to close again. Or
when the valve is designed to act as an escape or loaded safety valve, the
areas of the valve and of the diaphragm exposed to steam pressure, and
the weight on the lever or the tension or compression of the spring or
springs herein-before referred to, are so proportioned that the valve
opens, either when a certain amount of water has accumulated above it
or when steam of a pressure higher than the pressure previously fixed
upon as a limit is admitted to the chamber.
Under a modified arrangement of the steam trap the elastic diaphragm
or plate and the valve in lieu of being placed at the upper and lower
ends respectively of the vertical chamber or vessel as herein-before
described, are situate in separate branches projecting towards each other
from the upper and lower ends of the trap respectively.
The lower branch is that wherein the valve is placed, which valve is
arranged to open upwards, and it is pressed or held downwards on its
seat by a spindle, the lower end of which bears on the valve, whilst its
upper end which is or may be provided with a sole or palm, bears against
the elastic diaphragm or disc of india-rubber, metal, or other suitable
material, which is held in position on the flanch of the upper branch of
the trap by a ring or plate of metal.
Under this arrangement when a certain amount of water or condensed
steam has collected at the lower end of the vertical chamber, or when
the pressure of steam within the chamber becomes greater than the

page_text: limit determined upon, the valve rises and allows steam or water to
escape till the equilibrium of the valve and diaphragm is restored.
Under another modification the valve is seated in the lower part of
the vertical chamber. The elastic diaphragm is placed in a branch
projecting from the upper part of the vertical chamber, and is connected
by a rod with one end of a lever, the other end of which acts on the
valve spindle or on the valve itself and tends to keep it closed.
In this arrangement the equilibrium of the valve and diaphragm is
capable of adjustment by altering the relative lengths of the arms of
the above-mentioned lever, or by attaching thereto suitable springs or
weights.