Improvements in Steam Traps.
Year: 1893

page_text: Date of Application, 23rd Nov., 1893
Complete Specification Left, 23rd Aug., 1891--Accepted, 29th Sept., 1894
Improvements in Steam Traps.
I, JOHN JAMES ROYLE, of Dalham Works, Great Bridgewater Street,
Manchester, Engineer, do hereby declare the nature of my said invention to be as
follows:-
My invention has reference to steam traps for automatically discharging air and
water of condensation from steam apparatus, which operate by the expansion of
metals, and has for its object the simplification of the working parts and the
cheapening of the cost of manufacture.
In carrying out my invention I construct a box or casing hereinafter called the
casing, preferably of brass and within this casing 1 fit a strip of steel or other
metal having a lower ratio of expansion than the said casing. The strip is slightly
bowed or curved from the straight line and being secured at each extremity to the
brass casing (as hereinafter explained) is very sensitive to any change in the
length of the casing caused by alteration of temperature, such change in length
causing a considerable movement at or about the middle of the bow. A valve
controlling a steam and water way opening into the casing rests upon the metal
bow and thus the opening or closing of the way before mentioned is controlled by
the movement of the bow caused by the change of temperature. The bow may be
secured in various ways within the casing, but a very effective way is to use the
bow as the core bar in forming the casing and allow the metal of the casing to flow
around one end of the bar and so firmly fix it in position. The other end of the
bar passes out at the opposite end of the casing, and is screwed to receive a nut by
which the amount of bow' can be varied and the "setting" of the trap be
accomplished. According to another modification both ends of the bar may be
rast into the box, the bar in this case being in two pieces to allow for the con-
traction of the box on cooling, and afterwards joined by rivets. In this latter
modification the adjustment may be effected by moving the seating of the valve
nearer to or further from the bow in lieu of altering the amount of bow as herein-
before mentioned. An outlet is provided in the casing preferably opposite to the
inlet and to which is attached the usual pipe for carrying off the water of
condensation. In this way I produce a very cheap and efficient expansion trap
which is also very compact.
Dated this 22nd day of November 1893.
JOHN G. WILSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Steam Traps.
I, JOHN JAMES ROYLE of Dalham Engineering Works, Great Bridgewater.
Street, Manchester, Engineer, 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 :-
My invention has reference to steam traps for automatically discharging air and
water of condensation from steam apparatus, which operate by the expansion of
metals and has for its object the simplification and improvement of the working
parts and the cheapening of the cost of manufacture.

page_text: On the accompanying drawings
Figure 1 is an exterior view, Fig. 2 a longitudinal section and Fig. 3 a sectional
plan of my improved steam trap.
Figs. 4 and 5 are detached views shewing details.
In carrying out my invention I construct a box or casing (A), preferably of
brass, and within this casing I fit a bar (B) of, by preference thin steel having a
lower ratio of expansion than the casing (A). The steel bar is slightly bowed or
set-off as illustrated from the straight line and being connected at each extremity
to the casing (as hereinafter explained) is very sensitive to any change of
temperature (and consequently in the length) of the casing, such change in length
causing a considerable movement at or about the middle of the bar. Opposite this
point i.e., about the middle of the bar (B) the casing is provided with inlet and
outlet orifices (C) and (D) respectively, the inlet orifice being formed in a screw
plug. (E) screwing into the casing as illustrated. The plug forms the seating of a
flat faced valve (F) resting upon the bar (B) which under the movement of the
bar controls the inlet opening. This valve may be either formed with a projection
taking loosely into a hole in the bar to keep it in its proper position, or the same
may be formed without the projection and kept in position by the vertical guides (G)
forming part of and depending downwards from the plug (E), the under side of the
valve being rounded to allow the valve to rock on the bar and find its own seating.
Other forms of valve may be used, but I have found the one before described to
work well. It is also simple in form and easily and cheaply renewed.
The steel bar (B) inay be secured in various ways, but the most effective way is
to use it as the core bar in forming the casing and allow the metal of the casing to
flow round one end of the bar so fixing it in position as shown at the left hand end
of the trap. The other end of the bar passes out at the opposite end of the
casing through a packed gland as illustrated and is screw threaded to receive the
nut (H) by which the amount of "bow" can be varied and the "setting" of
the trap be accomplished.
The trap being connected up to the steam apparatus to be drained by means of
the inlet (C) the action is as follows:-
The normal position of the parts is as shewn in Fig. 2, the valve leaving the
inlet orifice open and allowing the water of condensation to pass freely through
the trap as indicated by the arrows. On the arrival of the steam the casing (A)
expands more than the bar (B) putting tension on the bar and so lifting the
valve (F) until it closes on to its seating. This condition of things continues so
long as a steam temperature is maintained in the casing (A), but should any
condensed water accumulate in the pipe leading to the trap and the temperature
of the casing fall in consequence, the contraction thereby caused slackens the
bar (B) and the valve falls and lets out the condensed water, closing again
immediately the steam arrives.
In this way I produce a very cheap and efficient expansion trap which is also
very compact.
Although I have described one end only of the steel bar as cast into the casing
it will be clear that both ends might be so cast, but the bar would have to be made
in two pieces overlapping in the middle to allow for the contraction of the casing
on cooling and be afterwards joined by a rivet or rivets. The adjustment of the
trap in this case may be effected by advancing the plug (E) nearer to or farther
from the valve (F).
In the modification hereinbefore described it will be observed that the action
takes place on the atmospheric side of the valve (F) and there is therefore little or
no pressure in the casing (A). A similar trapping effect would be produced by
admitting the full pressure of the steam into the casing and controlling the
outlet (D) by a valve pulled to its seating by the movement of the bar (B), but
this I should consider à modification of my invention and in my opinion it would be
less convenient in practice.

page_text: The valve (F) instead of being formed separate from the bar (B) may be cast on
such bar, say prior to the moulding of said bar into the casing and afterwards faced
up to correspond with the seating (C) in the lathe, the facing up tool being
introduced through the opening for the plug (E). This method of mounting the
valve is advantageous in that it is permanent and not so liable to get out of order
there being no loose parts.
Having thus particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I wish it to be
understood that I make no claim broadly to the expanding of metals in the
construction of a steam trap, but what I do claim and desire to secure by Letters
Patent is:
1st. In an expansion steam trap the use of a metal casing containing or enclosing
a bowed bar of less expansible metal and such bar operating under the elongation
or expansion of the said casing for controlling the flow of condensed water and
preventing the escape of steam substantially as set forth and illustrated.
2nd. In an expansion steam trap the use of the bowed bar (B) forming the core
bar for the casing (A) and moulded at one end into said casing and loose at the
opposite end and provided with a tightening nut substantially as set forth.
3rd. In an expansion steam trap the combination of the casing (A), bowed
bar (B), inlet plug (E), and outlet (D) valve (C) (or its equivalent), tightening
nut (H) when mounting and operating substantially as set forth and illustrated.
Dated this 22nd day of August 1894.