Year: 1886

page_text: I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents do hereby declare the nature
of this invention (a communication to me from abroad by Nelson Curtis of the
City of Boston, State of Massachusetts, United States of America) and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
The invention relates to a class of steam traps in which the opening and closing
of a valve in the outlet of the steam system to which the trap belongs is controlled
by the movement or position of the flexible side of an hermetically sealed metallic
vessel containing alcohol or other readily volatilizing fluid. In the art such vessels
are called expansion vessels. The flexible side bulges outwards or inwards or lies
in a plane according to the temperature of the enclosed fluid which temperature is
in turn determined by the temperature for the time being of whatever surrounds
the vessel be the same matter or air or steam or combinations thereof. The object
of steam traps of this description is to discharge the water of condensation within
the general steam system at any desired temperature.
In many cases it is desirable that this water be discharged as soon as the steam
takes the form of water. In other cases it is desirable to retain the water of con-
densation within the general system so long as such water shall have a requisite
temperature for heating purposes. Heretofore the outlet valve through which the
water of condensation escapes has been placed between the general steam system
and the expansion vessel.
But there are several disadvantages resulting from this arrangement or location
of the outlet valve perhaps the most important being that the apparatus cannot be
used for the discharge of water of condensation at a temperature above 212 degrees
Fahrenheit, that temperature being the highest attainable by steam or water in an
open vessel. Another disadvantage of the old arrangement or location of the outlet
valve consists in the liability of the expansion vessel to become heated from
extraneous sources; as for instance, when several traps discharge into a common
receptacle it not unfrequently happens that steam blowing off from one trap will set

page_text: back into another and heat the expansion vessel of the latter. By my invention
these disadvantages are overcome. The expansion vessel is placed directly within
the steam system and is controlled by the temperature of such system irrespective
of external sources of heat. It is immaterial whether the water of condensation is
at a temperature higher or lower than boiling point, and it is equally immaterial
whether the water of condensation is discharged into a vessel having a tempera-
ture higher or lower than itself. A part of my invention consists in placing the
outlet valve upon the other side of the expansion vessel, this bringing the expan-
sion vessel, as it were, within the general steam system. That is, in my apparatus
the expansion vessel instead of being located in a vessel opened to the atmosphere
(and indirectly or at times only directly affected by the temperature of the contents
of the general steam system only within limits that may exist in the atmosphere)
is located within a steam tight vessel or chamber which is within and thus made
a part of the general steam system and immediately affected by the temperature of
the surrounding contents of the steam system whether that temperature be high or
low. It is obvious that the variations of temperature in the contents of the
general steam may be confined to a much narrower range for operating the outlet
valve when the expansion vessel is located upon the inner side of the outlet valve
and surrounded by the water or steam of the general system than when the
expansion vessel is upon the further side of the outlet valve in a chamber or vessel
normally open to the atmosphere.
A very little heat applied to the whole surface of the expansion vessel will be
sufficient to heat the contents thereof to a certain temperature in comparison with
the amount of heat required to heat the same contents to the same temperature
when the heat is applied to a small fractional part of the superficial area of that
vessel. Moreover another advantage may be obtained by locating the expansion
vessel within a chamber forming a part of a general steam system.
In the old form of apparatus in which the valve or its stem is rigidly secured to
the flexible side of the expansion vessel when the elasticity of such flexible side is
lost through use or otherwise the valve will be opened and the apparatus discharge
cold water only under the pressure existing in the general steam system; and it is
obvious that if the valve be upon the further side of the expansion vessel only a
trifling pressure is required, since to move a valve of a small area, the pressure is
exerted upon substantially the whole area of the flexible side of the expansion
vessel, while in the old arrangement a great pressure is required since it is exerted
only upon the valve itself, and thus upon a small area. So, too, it is obvious that
when the expansion vessel is placed within the steam system the water of con-
densation or even steam may be readily discharged into a vessel or pipe already
. containing steam under pressure.
Another part of my invention, however, consists in the employment in a steam
tight chamber directly connected with, or adapted to be directly connected with a
steam system, so as to form a part thereof, and provided with an expansion vessel
and a valved outlet for said system as above set forth, of a spring arranged to
co-operate with the expansion vessel in controlling the valve of said inlet.
When a spring is used, in the manner herein set forth, at no time is the existence
of a steam pressure within the general system required and it is preferable
that the flexible side of the expansion vessel shall be merely flexible and not
elastic.
To clearly explain my invention reference is made to the accompanying drawing
which forms part of this specification and in which-
Fig. 1 represents a sectional view of the apparatus embodying my inven-
tion, and,
Fig. 2 represents a sectional view of a modification of some of the parts.
A, represents the general steam system, being in fact a pipe at the end of such
system.
B, is a casting having an inlet arm a, by which it is or may be attached to
the steam system A. The casting proper has open ends, but these are closed by

page_text: threaded caps or plugs b, and c, the latter being adapted to receive a discharge pipe,
as shown. The plug c, has through it a hole d, normally closed by a valve C, for
which the plug has a projecting support or guide e, as shown.
D, is the expansion vessel containing a volatile fluid, and having a flexible side ƒ,
as before described. It is supported, as shown, upon an arm g, which is screwed
into plug b, as shown, and has a slot in the end for the purpose of adjustment.
The arm g, ends in a recess in the plug b, which is closed by a cap h, as shown.
E, is a strong spring located as shown between the projection e, of the plug c,
and a shoulder upon the end of the stem of the valve C. This spring tends to lift
the valve from its seat and open the outlet; it also keeps the valve, or more
properly, the valve stem in constant contact with the flexible side f. of the expan-
sion vessel. The spring is strong enough to open the valve except when the
volatilizing fluid within the expansion vessel is sufficiently volatilized to overcome
its force and close the valve.
With this construction therefore no steam pressure is required to open the valve.
But in the form of apparatus shown in Fig. 2, the spring is omitted, and the valve
stem is riveted to the flexible side of the expansion vessel, as shown. This form
of construction will answer with steam systems of light pressure. The chamber or
casting B is provided with a blow-off cock G, as shown.
The mode of operation of the above described apparatus embodying my improve-
ments is obvious.
The form in which the spring is employed is particularly desirable in low
pressure heating apparatus.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is-
1. The combination with a steam system, of a steam trap consisting of a steam
tight chamber provided with an open or free inlet passage communicating with
said steam system, a valved outlet passage, and an interior expansion vessel, the said
expansion vessel controlling the valve of the said valved outlet passage, substantially
as described.
2. A hollow casting or chamber provided with a free inlet passage and a valved
outlet passage and containing an expansion vessel and a spring, the said spring
and said expansion vessel being arranged to work in opposition to each other and
govern the valve in said valved outlet passage, substantially as described.
Date L 1
C
1 1000