IMPROVEMENTS IN SAFETY VALVES
Year: 1885

page_text: We GEORGE WILSON of N° 5 Oak Grove Anerley in the County of Surrey
Engineer and ILLIUS AUGUSTUS TIMMIS of N° 2 Great George Street Westminster
in the County of Middlesex Civil Engineer do hereby declare the nature of our
invention for IMPROVEMENTS IN SAFETY VALVES, to be as follows:-
The objects of our Invention are to make a safety valve which shall be.
Firstly-A minimum of size and weight.
Secondly-Shall require a small spring, or a small dead weight or lever weight.
Thirdly Shall have a maximum amount of steam escape area, and
:
Fourthly At the same time be exceedingly sensitive and so allow the valve to
blow off with a minimum rise in steam pressure over the normal & to regain its
seat, as nearly as possible, at the normal.
.
With these objects in view we construct a safety valve with two seats, one above
the other. The diameter of the top seating being larger than that of the lower.
Both seatings are mitred in the same way (generally to the same angle) they
are kept as near as possible to each other, so that their relative positions are not
altered by the expansion and contraction of the metal forming and between them.
At the same time the space between is sufficient to give ample room for the steam
to reach both valve seats.
The two valves
Each seat has a valve that rests upon it in its normal position.
are joined (and are generally one and the same piece of metal). The top valve
being of larger diameter than the lower; the space, or pillar of metal between
them, which may be hollow or solid, is made of the same exterior diameter from
top to bottom as the outside diameter of the bottom valve, or the outside diameter
may gradually increase from bottom to top so that there is no downward direct
pressure of steam on the bottom valve & so the difference in the diameter of the
top and bottom valves may be any required amount. The difference of the area
of the two diameters multiplied by the steam pressure is the force which has to be
provided against in calculating the power of the spring and weight on valve.
It is clear that this differential area can be regulated, when the valve is made,
to any required amount.
We make the valve with a coned shaped hollow in it from the top, so that the
rod or spindle carrying the spring or weight may rest on the valve at a point as
far as possible below its centre of gravity. The valve may be made solid, or if

page_text: desired the centre of the valve may be hollow and used in conjunction with the
other outlets as an exhaust pipe thereby increasing the exhaust area and giving a
freer escape for the waste steam the valve being kept to its seatings by a spring,
or weight resting on its outside wall any number of openings may be made for the
escape of waste steam that may be found convenient.
The valve can be cased in and locked up. It can also be fitted with lifting and
turning gear so as to comply with the Board of Trade regulations and Insurance
Rules.
The valve can be arranged to work with a spring in tension instead of com-
pression and the spring or dead weight may be applied to keep the valve on its
seat either directly or by means of levera
With this valve a very small spring is sufficient even where valves of large
diameter are used and there being two valve seats there is double the escape
area for steam as compared with. other valves with the same lift and thus a
more sensitive and a more economical and a much lighter valve is produced than
heretofore.
The improvements are also applicable to safety valves for steam economisers,
bath and domestic Boilers and other water heaters with both high and low
pressure.

page_text: Improvements in Safety Valves.
We GEORGE WILSON of No 5 Oak Grove Anerley in the County of Surrey
Engineer and ILLIUS AUGUSTUS TIMMIS of No 2 Great George Street Westminster
S.W. in the County of Middlesex Civil Engineer do hereby declare the nature
of our invention for IMPROVEMENTS IN SAFETY VALVES and in what-manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
.
The objects of our Invention are to make a safety valve which shall be.
Firstly: A minimum of size and weight.
Secondly Shall require a small spring or a small dead weight or lever weight.
Thirdly Shall have a maximum amount of steam escape area, and
Fourthly At the same time be exceedingly sensitive and so allow the valve to
blow off with a minimum rise in steam pressure over the normal to regain its
seat, as nearly as possible at the normal.
With these objects in view we construct a safety valve with two seats one
above the other. The diameter of the top seating being larger than that of the
lower.
Both seatings are mitred in the same way (generally to the same angle) and they
are kept as near as possible to each other, so that their relative positions are not
altered by the expansion and contraction of the metal forming and between them.
At the same time the space between is sufficient to give ample room for the steam
to reach both valve seats.
Each seat has a valve that rests upon it in its normal position. The two valves
are joined (and are generally one and the same piece of metal). The top valve
being of larger diameter than the lower; the space or pillar of metal between
them, which may be hollow or solid, is made of the same exterior diameter from
top to bottom as the outside diameter of the bottom valve, or the outside diameter
may gradually increase from bottom to top so that there is no downward direct
pressure of steam on the bottom valve and so the difference in the diameter of the
top and bottom valves may be any required amount. The difference of the area
of the two diameters multiplied by the steam pressure is the force which has to be
provided against in calculating the power of the spring and weight on valve.
-
It is clear that this differential area can be regulated when the valve is made to
any required amount.
We make the valve with a coned shaped hollow in it from the top, so that the
rod or spindle carrying the spring or weight may rest on the valve at a point as
far as possible below its centre of gravity. The valve may on the other hand
be made solid, or if desired the centre of the valve may be hollow and used in
conjunction with the other outlets and exhaust pipe thereby increasing the exhaust
area and giving a freer escape for the waste steam the valve being kept to its seatings
by a spring, or weight resting on its outside area. Any number of openings may
be made for the escape of waste steam that may be found convenient.
The valve can be cased in and locked up. It can also be fitted with lifting and
turning gear so as to comply with the Board of Trade regulations and Insurance
rules

page_text: The valve can be arranged to work with a spring in tension instead of com-
pression and the spring or dead weight may be applied to keep the valve on its
seat either directly, or by means of levers.
With this valve a very small spring is sufficient even where valves of large
diameter are used; there being two valve seats there is double the escape area for
steam as compared with other valves with the same lift and thus a more sensitive
and a more economical and a much lighter valve is produced than heretofore.
The improvements are also applicable to safety valves for steam economisers
bath and domestic boilers and other water heaters with both high and low
pressure.
bath and domestic boilers and other water heaters with both high and low
pressure.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal view of the general arrangement of the valve half in
section and half in elevation.
Figure 2 is a vertical section the right hand half on line W, K and left hand
half on line X, Y, Fig. 4.
Figure 3 is an end elevation and Fig. 4 is a plan half in section and half in
elevation on lines L. M. & O. P. respectively.
Figure 5 is a plan of the valves.
Figure 6 is a section of same.
Figure 7 is a section on line 7 & 8.
Figure 8 is an inverted plan of the valves..
The same letters of reference apply to all the figures of the Drawing.
A is the top seating which is made of larger diam: than the bottom seating B.
The steam enters at the inlet F and acting on the valve, forces it from the
seatings A & B and overcomes the pressure, caused by the spring or weight E
which is carried on the rod D therefore the steam escapes in two ways one upwards
through the seating A & thence pass the spring into the open air and the second
way of escape being in the direction of the cavity below the valve and thence
through the outlet g.
•
H, H are the tension bolts which are provided with a thread and nuts these
force the spring plate I downwards till sufficient pressure is put upon the spring
to obtain the required steam pressure.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that
what we claim is
The construction of a Safety Valve practically as and for the purposes herein-
before described.