Improvements in Relief Valves for Permitting the Escape of Entrapped Water from Steam Engine Cylinders, and for like use in other Cases.
Year: 1898

page_text: Date of Application, 3rd Mar., 1898
Complete Specification Left, 5th Dec., 1898-Accepted, 14th Jan., 1899
PROVISIONAL SPECIFICATION.
Improvements in Relief Valves for Permitting the Escape of
Entrapped Water from Steam Engine Cylinders, and for like
use in other Cases.
I, CHARLES ARTHUR ALLISON, of 52, Chancery Lane, London, in the
County of Middlesex, Patent Agent, do hereby declare the nature of this invention
(which has been communicated to me from abroad by John Clinton Parker, of the
City and County of San Francisco, State of California, United States of
America) to be as follows:-
My invention consists in providing at the ends of steam or other engine
cylinders valves that will automatically open outward at a superior or prede-
termined pressure within the cylinder, such valves when not in action being held
closed against the normal working pressure in the engine cylinder by means of
fluid pressure applied on the back of the valves and preferably derived from the
same pressure by which the engine is operated, such counter or closing pressure
being attained by placing the relief or escape valves in, or in connection with, the
valve box, steam jacket, or other chamber, or passage of the engine subjected to
the static pressure of the steam supply, which acting on the back or larger area
of the valves, they are held shut against the working, or some predetermined
pressure within the cylinder, but open freely when such pressure is exceeded by
reason of entrapped water, which after escaping is either re-evaporated or drained
away; the valves being devoid of springs (except to sustain their gravity in some
cases) or any other mechanical co-operating part, or accessory, and not requiring
adjustment or care when once set or mounted.
Datad this 2nd day of March 1800
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Relief Valves for Permitting the Escape of
Entrapped Water from Steam Engine Cylinders, and for like
use in other Cases.
I, CHARLES ARTHUR ALLISON, of 52, Chancery Lane, London, in the
County of Middlesex, Patent Agent, do hereby declare the nature of this invention
(which has been communicated to me from abroad by John Clinton Parker, of the
Pine 871

page_text: City and County of San Francisco, State of California, 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:-
This invention relates to an improvement in what are technically called relief
valves, to permit the escape of water entrapped in steam engine cylinders.
The improvement consists in providing at each end of a steam engine cylinder,
or at one end, if both ends are not exposed to entrapped water, an escape valve
or valves communicating with an exterior chamber containing a pressure equal
to that of the steam in the engine cylinder; such valves being so mounted as
to open automatically by a superior pressure within the cylinder, and be held
shut, when not in action, by contra pressure on the other or outer side of the
valves; these remaining closed under normal working pressure in the steam
cylinder, and opening when from any cause the pressure within the steam
cylinder rises above that of the static pressure in the outer chamber into which
the valves open, or communicate with.
The object of my invention is to avoid water obstruction in steam cylinders by
permitting its escape through valves of sufficient area into an enclosed chamber,
when the pressure exceeds that of the steam in the boiler, or some predetermined
static pressure in the enclosed chamber into which the relief valves open, and
thus, without loss of steam, guard against accidents due to entrapped water.
Referring to the drawings for further explanation of this invention:
Fig. 1 is a central longitudinal section through a steam engine cylinder, pro-
vided with disc relief valves opening into steam jacket chambers in the cylinder
heads.
Fig. 2 is a central longitudinal section through a steam engine cylinder, having
hinged relief valves placed beneath the cylinder.
Fig. 3 is an end view of Fig. 1.
Fig. 4 is an end view of Fig. 2.
Similar numerals of references indicate corresponding parts in the different
figures of the drawing.
In that class of steam engines provided with piston or other positive closing
valves, safety demands provision for the sudden escape of entrapped water.
To render such escape as free as possible, both as to volume and resistance and
to avoid waste of heat and steam, construct devices as shown in the drawing,
1 being the steam cylinders; 3 the pistons, and 2 the piston rods of the engines
provided with my improvements.
Steam ports 4 communicate to each end of the steam cylinder from the valve
boxes 5 in the usual manner, and 6 are relief valves opening communication from
each end of the steam cylinders to the chambers 8; in Fig. 1 directly and in Fig. 2
by means of the ports 7.
In Fig. 1 the chambers 8 are in communication with the valve box 5 by means
of a pipe 9 seen in Fig. 4, or by a port 10 extending partially around the cylinder,
to the valve box 5 as indicated by dotted lines in Fig. 3, or these chambers 8
may communicate by means of pipes 11 direct to a steam boiler or other vessel
under pressure equal to the maximum working pressure in the steam cylinders.
The valves 6 can be of the disc form as shown in Fig. 1, opening directly from
the interior of the cylinder 1, or of the hinged kind as seen in Fig. 2, placed in
the conduits or ports 7, the construction being immaterial so long as the opening
and closing movement is free.
The horizontal moving valves and other features of construction as shown in
Fig. 1, are especially adapted for engines of high speed, requiring a large amount
of entrapped water to be suddenly discharged into the chambers 8 and ports 12,
or into a steam jacket space around the cylinder, when such is available.
The chambers S being, when properly drained, partially filled with steam pro-
viding an elastic resistance to water suddenly discharged therein; also permits
relief of over pressure in the steam cylinder from compression, steam, or other
cause, thus acting in the manner of safety valves.

page_text: In Fig. 2, the valves, being below the bottom of the cylinder, drain off by
gravity any water that collects in the passages 7.
The operation is as follows;-If the water becomes entrapped in the cylinder
it is forced out by the piston 3 through the valves 6 into the chambers 8 and from
there through the pipe 9, or the passage 10 into the valve boxes 5, or may be
expelled through the pipes 11 leading to the steam boiler, or any closed chamber
containing a static pressure equal to that of the maximum working pressure in
the steam cylinder 1.
As soon as the entrapped water is expelled, and the pressure in the cylinder
diminishes the valves 6 close by the superior pressure in the chamber 8.
It will be seen that by the valves 6 being in a closed circuit and not opening
to the air, no steam, water, or heat can escape or be lost, and that leakage does
not cause any waste worth considering. It will also be seen that no adjustment
or attention is required, and that the action of the valves 6 will be reliable under
all circumstances.
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 engine, relief valves communicating between the end or ends
of the cylinder and a closed chamber containing pressure equal to that of the
steam in the cylinder and opening outward when the pressure in the cylinder
exceeds that in the chamber into which the valves open.
2. In a steam engine a relief valve or valves communicating with the steam
cylinder, opening outward therefrom into a chamber or steam jacket space
around the cylinder in communication with the steam boiler or other source
of initial pressure, equal to that of the steam in the cylinder so that the valve
will open when the pressure in the steam cylinder exceeds that on the back of
the valves.
Dated this 5th day of December 1808