Year: 1887

page_text: Date of Application, 22nd Sept., 1837
Specification Accepted, 29th Mar., 1888
I ALEXANDER DUNCAN MARSHALL of Balmain near Sydney in the Colony of New
South Wales, Engineer, Surveyor to the Marine Board of the said Colony 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 those kind of apparatus by which water or condensed
steam is drawn away from reservoirs or receptacles while at the same time steam is
not allowed to escape. It has been devised so that the valve by which the water
escapes will be automatic and very sensitive in its action and so that a steam trap
will be produced most reliable in operation more economical in construction and of
very long relative life compared with those hitherto constructed.
This improved automatic steam trap consists essentially of a container to receive
the condensed steam elastically retained against its discharge valve and allowed move-
ment therefrom so that it will support itself and only a certain quantity or weight of
water with the valve closed.
But in order that this invention may be clearly understood reference will now be
made to the drawings herewith in which Figure 1 shows a steam trap constructed
according thereto and Figure 2 a plan partly in section of the same while Figure 3
shows on a smaller scale an elevation of a discharge pipe or a supply pipe or pipe for
joining the steam trap to the reservoir or receptacle from which water without steam
is to be drawn.
A is the container preferably in two pieces bolted together-B is the inlet and
C the outlet. D the supporting spring-E a saddle or frame and Fa guage glass
and cocks-A¹ is a mud well A a plug A holes for guide rods-B Figure 3 is a
pipe for supply or for discharge made in the form of a spiral-0 is a equilibrium
valve-C its spindle-C stuffing box and gland-C adjustable jamb nuts-D¹ is
adjustable socket for spring-D jamb nut-E are guide rods held firmly in saddle E
and by top plate E-E³ are bolts for attaching saddle in a permanent position-
Fis pet cock.
The level of the water in the container A having been predetermined the saddle E
being firmly bolted in position the joints of the spiral pipe B to say the steam jacket
of engine cylindes or to other reservoirs in which steam is to be trapped and to
inlet B being tightly made and a waste pipe say a spiral pipe being attached to
outlet C the valve spindle C is "jambed" to plate E by nuts C and the spring D

page_text: being placed around mud well A¹ is adjusted by means of screwed socket D¹ uniil
the weight of the water which it is desired should remain in the container will retain
the valve C tight upon its seat and the socket D1 jambed in its adjusted position by
nut D-Now when the water rises above the desired level in the container the extra
weight will cause a compression of the spring D and the container A will slide down-
wards on rods E and its scat will fall away from valve C and thus open such valve-
The extra water will now discharge this outlet C during which time the spring D
is exerting itself to close valve C₁ which it accomplishes just at that moment when
the desired level of the water in the container is reached and should at any time the
water in the container become too low the spring D will retain the valve C with a
very tight bearing on its seat until such level is exceeded-The use of the mud well A¹
and plug A the guage glass F and the pet cock F¹are too well understood to need
any remarks relating thereto.
may if it be thought desirable construct the equilibrium discharge valve in a
separate box either cast or otherwise fastened on the outside of the container or the
discharge may be regulated by means of a cock or cocks actuated by levers receiving
motion on the movement of the container as its weight compresses or expands the
supporting spring.
This steam trap will operate under any direct internal pressure and it will be seen
that the opening and closing of the valve is entirely due to the weight of the contents
of the container compressing the supporting spring or allowing said spring to expand
as the case may be.
I would have it understood that I do not confine myself to the precise construction
of steam trap or its various details described and illustrated so long as the nature of
my invention be retained and :-
-
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare what I
claim is.-
First An improved steam trap in which the container to receive the water or
condensed steam is elastically supported elastically retains its discharge valve in a
tightly closed position and is allowed movement to open such valve substantially as
herein described and explained.
Second An improved steam trap in which an excess weight of water in the
container causes the compression of an elastic cushion or support and the opening of
a discharge valve substantially as herein described and explained.
Third The combination and arrangement with a container for water or condensed
steam having a sliding up and down movement on guide bars of a spring supporting
the said container and a valve spindle and equilibrium valve (whether inside or outside
of such container) both held in a rigid frame or saddle substantially as herein described
and explained.
Fourth The combination and arrangement with a sliding container for water or
condensed steam of spiral supply and discharge pipes or of supply and discharge pipes
with sufficient elasticity to allow of the necessary movement of said container.
Dated at Sydney in tho Colony of New South Wales this Sixteenth day of August
One thousand eight hundred and eighty seven.