Improvements in Steam Traps.
Year: 1899

page_text: Reprinted as amended in accordance with the decision of the Comptroller General
dated the 18th day of July 1899.
Date of Application, 25th Jan., 1899-Accepted, 4th Mar., 1899
WATTE DIMITICATION.
Improvements in Steam Traps.
I, JOHN WILLIAM NASMITH, of Norwood, Mauldeth Road, Heaton Mersey,
near Manchester, in the County of Lancaster, 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 relates to steam traps such as are used for the purpose of dis-
charging the water of condensation from vessels in which steam is used for various
purposes. It has for its object an improvement in the method of construction
whereby the parts are much simplified and by means of which the work of dis-
charge is rendered safer and more effective.
In many cases hitherto steam traps have been made which speedily became
ineffective by reason of the parts falling out of repair. When high pressures
are used it is undesirable to let the steam enter the body of the trap as otherwise
there is considerable danger even when the body is made stronger for the purpose.
I adopt such a construction as enables me to ensure against the entrance of any
steam into the body of the trap or float by providing such a means of inlet as
ensures it being condensed prior to its passage through the valve. I also so
arrange my parts that a very slight movement of the float is sufficient to open and
close the valve which I construct so that it has a reciprocal vertical movement
corresponding to the direction of the motion of the float. I employ in com-
bination with the valve and float a screwed rod extending through the cover of the
trap whereby I am enabled to control from without the said trap the extent of
movement required to close the said valve. The general effect of my improve-
ments is that I obtain a sensitive but positive action of the valve which only acts
to admit the water of condensation formed prior to its entrance within the said
trap.
In order that my said improvements may be better understood and more easily
carried into effect, I have hereunto appended a sheet of drawings wherein Fig. 1
is a partial vertical section, Fig. 2 shows respectively front and side elevations
and plan view of the valve seat casting and Fig. 3 side view and plan of the levers
coupled to the valve.
In carrying my said invention into effect I construct a cylindrical or other
suitably shaped case A of cast iron or other material having an inlet pipe formed
at B and an outlet at D. The inlet pipe projects upwards within the said case
for a sufficient distance so as to form a central column. I may form the column
as part of or attached to the case A and convey the steam thereto by an ordinary
pipe placed below the said case. I bore out and thread the upper portion of B
and screw into the same the screwed shank of the valve bracket E (Fig. 2). On
either side of E ears El are cast to which the levers H are pivotted by means of
the pins M. Between the said ears E a bridge piece T is formed which is bored
out to receive the valve plug P. At the point a lip is suitably turned to act

page_text: as a valve seat, and the plug P is recessed at 1" for the reception of an ebonite
or other suitable washer which is held in position. by a small screw and can be
renewed when required. The upper end of P is also recessed to receive the
lower end of the screwed thrust rod S. A small pin is passed through P and S so
as to couple them loosely together in such a way that while the plug rises with S
the thrust is on the end of S and not on the pin. On the screwed portion of the
thrust rod S a square nut W is threaded which is formed with a groove on each
side for the reception of the pins K fixed in the levers H (shewn in Fig. 3) the
forks of the said levers overlapping the nut W.
The levers H form one of a series of the well known "lazy tongs" type which
are coupled by means of a link G¹ to the rose G fastened to the bell or float Y
by the nut N. I may employ any suitable method of attaching the levers to the
rose G other than that shown so as to avoid lateral friction on the rod S on
which the said rose slides but in most cases the arrangement shown will be satis-
factory.
The rod S is coupled as previously described to the valve plug P and also passes
through the rose G and the cover of the case. In the centre of the cover a hole
is formed for the reception of the collar L which is formed with a square shank.
The said collar can be fixed to the thrust rod by a set screw to prevent the rod
from turning after being adjusted, and the square shank is of sufficient length to
permit the rod rising without the shank coming out of the hole.
The float or bell Y is cylindrical in shape with one end open the closed end
being uppermost and the open end being scaled by water in the ordinary way.
The bell has as previously described, the rose G fixed to it the levers actuating
the valve being coupled to the said rose. At one point in the top of the float in
addition to the ordinary vent a valve R may be placed to permit the escape of
any air which may enter with the water or to relieve any excessive pressure
within the bell. The valve may be suitably weighted or not and may be con-
structed in a variety of ways all of which are well known.
The action of the mechanism so described is as follows. Assuming the inlet B
to be closed or not to be passing water the case is partially filled with water to the
level of the inlet D and the valve P is raised. When the flow of steam and
water commences the first effect is to discharge through the valve the water pre-
riously condensed until the central column is emptied. The incoming steam
and water being hot raises the temperature of the column and after a short time
the water immediately about it commences to boil and so sets up a pressure within
the float Y. When the trap is starting work and all the parts are cold the
ebullition takes a little time but when all the parts are warm the presence of
a small amount of steam speedily creates the necessary amount of pressure. Thus
before any steam can enter the float Y the latter has been raised by the pressure
created as described.
The raising of the float causes a movement of the levers H on their fulcra M
and the pressure of the pins K on the nut W presses the valve plug down on its
seat. The entrance of water is thus prevented until condensation has again
occurred within B and its connections when the emission of vapour ceases and the
float Y descends thereby opening the valve P and permitting the water to escape.
The amount of elevation of the float Y necessary to close the valve can he
adjusted by turning the rod S in the nut W and then fixing the collar L. By
these means the amount of movement of the bell necessary to ensure effective
closure of the valve can be simply and effectively regulated from without.
I am aware that the employment of a float to close the valve is common to
many previous devices and I am also aware of the Letters Patent of Victor Aimé
Prost No. 17819 of 1890 of which I am the registered owner. In the invention
of the said Letters Patent the elevation of the float is accompanied by its rotation
limited extent being communicated to a screwed valve spindle which forces
the valve on to its seat formed on the top of a central column within the float.
The parts by which the rotary movement of the valve and the float are obtained
to a.

page_text: are external to the trap and I have found by practice that there is considerable
friction, especially under high pressures which materially effects the working
of the trap. I find further that it is desirable to provide means for adjusting
the valve of a special character in order to ensure positiveness and delicacy of
movement.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
(1) In a steam trap the mechanism consisting of a vertical inlet pipe a valve
seat fixed thereto a valve capable of vertical movement controlled by the move-
ment of a bell or float to which the said valve is operatively connected by a series
of levers a rod loosely attached to the said valve, and capable of being adjusted so
as to limit the range of movement of the said valve all arranged and combined in
the manner and for the purposes substantially as herein described and illustrated.
(2) In-n-steam-trap the combination-with-the-Falve-seat-formed within the float
or-bell-of-a-valve-which-is-moved vertically by means of a series of levers-coupling
the-valve and the feat the whole-being so arranged that the elevation-of-the-flont
closes the-valve-substantially-as-herein described-and illustrated.
(2). (3) In a steam trap the employment of a screwed rod attached to the valve
the said rod being adjustable so as to limit the movement of the valve substantially
as herein described and illustrated.
Dated this 95th day of Janua 1800
JOSEPH NASMITH,
Agent of the Applicant.