Improvements in Steam Traps.
Year: 1893

page_text: GUMI LIPID DI BUITIVATION.
Improvements in Steam Traps.
I, ALEXANDER TURNBULL, of St. Mungo Works, Bishopbriggs, in the County
of Lanark, North Britain, Engineer, 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 :-
This invention relates to improvements in steam traps for discharging condensed
water. Inside the trap a valve is provided which is automatically opened when
the condensed water reaches a certain height in the trap. According to one
modification of my invention the discharge valve is automatically opened by the
floating of a body attached to the valve as the water rises in the trap, but according
to another modification I make use of the difference in expansion by heat of
different metals to cause the valve to automatically open.
In order that my invention may be properly understood and readily carried into
effect I have hereunto appended two explanatory sheets of drawings in the several
figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 represents the modification of my invention when the discharge valve
is opened by the float. In Figure 2 the valve is caused to open by the difference
in expansion of different metal rods.
Referring to Figure 1, A is the trap for condensed water and steam. B is the
valve kept closed by the gravity and the pressure of steam.
The condensed water
and steam are admitted to the trap by the pipe C. Attached to the valve stem
there is a can or vessel D which is kept full of water and the condensed water falls
down into the space between the can and the sides of the trap. The upper end of
the valve stem is connected to a screwed rod E by means of a spring F. The rod E
passed through a tapped hole in the cover of the trap. The tension on the spring
can thus be adjusted so as to counteract part of the weight of the can D and
contents and the steam pressure on the area of the valve, so that when the condensed
water rises to a certain height the can will be floated up and the valve lifted. The
condensed water will then be blown out through the discharge pipe G by the steam
pressure. In Figure 1 the spring is shown in tension, but it is obvious that it might
be arranged in compression. Also instead of the valve closing downwards it may
be arranged to close upwards, and the water discharged through a central pipe.
Figure 2 represents the modification of my invention in which I make use of the
different expansions of different metal rods or tubes or the combination of rods and
tubes to automatically open the valve and allow the condensed water to escape.
A is the trap, B the valve, and the pipe by which the condensed water and
steam are admitted to the trap. The valve stem D which may be a rod or tube
made of some metal having a large coefficient of expansion passes through a
plate E and is attached to an upper plate F. The upper and lower plates are
connected together by means of two rods or tubes GG made of another metal
which has a small coefficient of expansion. Two rods or tubes H H made of the
inetal with a large coefficient of expansion are bolted to a plate I which is carried
by a bolt J screwed into the cover of the trap. The lower ends of the rods or
tubes H are attached to the plate E. A light spiral spring L between the
cover and the plate I keeps the plate I bearing on the flange of the bolt J. The
whole arrangement of rods or tubes is suspended from the adjusting bolt J. The
condensed water falls into the trap and as it gradually rises up the lower ends of
the tubes or rods D, G and H become immersed in the water. As the temperature
of the water is lower than that of the steam the tubes or rods will contract, and the

page_text: higher the water rises the greater will be the contraction in the rods. The con-
traction of the rod or tube D will tend to make the valve lift off its seat, but the
contraction of the rods or tubes G G will bring the plate F nearer to the plate E,
and will tend to close the valve, but as the contraction of D is greater than that of G
(if we had only the tubes or rods D and G to consider) the valve will be lifted
by an amount equal to the difference in contraction between the tubes or rods D
and G. But the rods H will also contract and carry the plates E and F up and
tend to open the valve further while the contraction of the casing of the trap will
cause the valve seat to rise up towards the valve.
The result of this arrangement will be that the valve will be lifted by an amount
equal to the excess in the contraction of the tubes or rod D and H over the
contraction of the rods G and the casing of the trap. When the water rises high
enough to cool the rods or tubes sufficiently the valve will be opened and the con-
densed water will be blown out through the discharge pipe K.
The amount by which the valve is lifted for a given diminution in temperature
of the tubes or rods is regulated by the number of pairs of rods or tubes of
different expansibility employed with their corresponding plates.
The series of rods or tubes may be arranged in a plane or in the area of a
-circle.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what
claim is
1. In steam traps, the application of a spring for adjusting or regulating the
pressure on the valve seat, so that when the water rises to a certain level in the
trap the valve will be opened and the condensed water discharged substantially as
described with reference to Figure 1.
2. The steam trap for discharging condensed water substantially as described
with reference to Figure 2.
Dated this 23rd day of March 1002
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.