IMPROVEMENTS IN SAFETY VALVES FOR STEAM ENGINES
Year: 1884

page_text: I, HERBERT JOHN HADDAN, of 67, Strand, in the City of Westminster, Civil
Engineer, do hereby declare the nature of my invention for IMPROVEMENTS IN
SAFETY VALVES FOR STEAM ENGINES, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
Reference being had to the accompanying plates of drawings, illustrative thereof,
of which in plate 1.
Fig 1 is a vertical section of a safety valve mechanism provided with the
invention in part. Fig 2 is a top view, and Fig 3 a horizontal section of such
safety valve, the latter section being taken through the wheel shaped valve seat
base to be described-
In plate 2-
Fig 1 is another vertical section of a safety valve and its operative mechanism
provided with this invention in part. Fig 2 is a horizontal and transverse section
taken on line A¹ B' of Fig 1. Figs. 3 and 4, are transverse sections of the valve
and its seats, as somewhat differently constructed from those shown in Fig 1.
Fig 5 is a transverse section on an enlarged scale of the deflectors q and i, and part b
of the valve A, as shown in said plate 2, and described. Figs. 6 and 7 are
hereinafter explained. Fig 8 is another vertical section of a safety valve having
this invention in part. Fig 9 is a horizontal section on the line A¹, B¹, of Fig 8.
Fig 10 is an underside or bottom view of the valve-and Fig 11 is a top view of the
valve seat base.
The nature of this invention is defined in the claims hereinafter presented.
In Fig 1 of plate 1 of such drawings, a safety valve is shown at A, a wheel shaped
base B, having two concentric annular seats a and b, for the valve to rest on.
This base is tubular, and provided with a tubular hub c, supported within the bore
of the base by means of a series of radial and tubular armis d, extending from the
hub to the base, and each opening out of the said base and into the bore of the hub
in manner as represented. The bore of the hub is closed at bottom as shown at e.
From the valve, a stem s, fluted or having narrow fillets t, vertically on its
periphery, extends into the bore of the hub c. The fillets bear against the bore and
serve to guide the valve rectilinearly in its movements towards or off its seats.
Encompassing and screwed on the base is a gate or ring C which on being
screwed down about the passages leading through the arms d, suffices to close the
ends of such passages more or less, to intercept and regulate the egress of steam

page_text: from them.. This ring is prevented from accidentally revolving by a screw ƒ which
screwed into the encompassing shell or outer case D, within which the valve and
the base B are arranged as shown, bears against such ring.
Projecting upward from the valve is a spindle E, which extends above and below
and is fixed to the bottom g of the case or jacket F, of the spiral spring G of the
valve A. The said spring rests on the said bottom g which is screwed into the
lower part of the body of the case, and not only constitutes a bottom for the case
but a support for the spindle and the spring.
On the top of the spring is a cap or disc h, upon which the lower end of a tubular
screw bears. This screw is screwed into an arched support I resting on and
fastened to the top or crown of the case D. The tubular screw H goes through and
fits in the bore of a tubular neck i, extending up from the top or crown of the jacket
or case F, and through the crown or top of the case D, such neck being to steady.
the case F and admit of such case being moved upward and downward.
The body of the case F is conical or tapering in its upper part as shown at k, to
deflect steam to and through openings or educts 7, in the crown of the case D, and
to prevent such steam in a measure, if not entirely from passing up into and
through that opening in the crown of the case 'D, through which the tubular neck i
extends.
↑
Screwed upon the said crown of the case D, is a hood or dome K, provided with
two ears m m, extending from it, at its lowest part, in manner as shown in the
drawings, each of such cars having a hole through it laterally. A pin L goes down
between these ears and into the crown of the casing D, and each pin has through it
a hole in line with those of the two ears. The holes of the pin and ears are to
receive the hasp of a padlock, in order to prevent the head from being unscrewed
for improper access to the parts within it." N is a lever for forcing the valve off its
seat by a screw O applied to such lever and the case D in manner as shown.
I would remark that if desirable, the case D may have a steam discharge opening
or openings in its lower part.
The operation of the described mechanism may be thus explained.
The valve resting on the two flat annuli seats a and b, will be held down thereon
by the spring G, against the pressure of steam when such may tend to force the
valve off its seats. The tension of the said spring may be increased by screwing
down the screw E. The valve area between the two seats is what the steam
pressure ordinarily acts upon to overcome the resistance of the spring. The area
bounded by the sinaller seat, will not be so acted on by the steam until the valve
may be forced upward off its seats. When the pressure of the steam under the
valve is nearly to the maximum required, the valve will open or rise slightly and
the steam will escape across the larger of the valve seats into and up through the
case D, and impinging against the tapering part k of the spring case or jacket F,
will by such part be deflected into and through the openings of the case D. The
steam will also be forced inward across the inner valve seat and thence down
through the hub c and the tubular arms d, from whence it will pass into
and up through and out of the case D. On the pressure liaving attained
the maximum the valve will be forced upward so as to allow the steam
to act on the valve area within or bounded by the inner seat and thereby
produce a greater pressure on the valve, one to suddenly overcome
increasing resistance of the spring and force the valve higher, so as to rapidly
relieve the boiler. After this the valve will slowly settle down and close upon its
.⚫ seats.
the
By depressing the gate C so as to diminish the escape of steam through the
tubular arms d, the pressure on the valve area bounded by the inner valve seat may
be diminished. Thus it will be seen, that by such gate, such pressure may be
regulated or diminished or increased, as occasion may require.
Having thus described the part or parts of this invention illustrated in plate 1,
I shall now proceed to explain that or those shown in Figs. 1 to 7 inclusive of
plate 2

page_text: In Figs. 1, 3 and 4 of plate 2 the valve A, is represented as a compound one, it;
in said Figs. 1 and 3 being shown as composed of a central disc bearing a, and a
single ring or annular valve bearing b, concentric with each other, and connected by
arms c, extended from one to the other as the spokes of a wheel do with referenco
to its hub and rim. In Fig 4, however, the valve bearing a, is shown as an annulus
in cross section.
In the said Figs. 1, 2 and 3, of plate 2, the valve is represented as provided with
a guiding sleeve d, that extends upward within the cylindrical case or cover e, of
the valve spring f, such case e being extended down within and above a tubular
casing h, and connected therewith by a series of radial arms i, there being spaces
between the arms for the escape of the steam in passing through the casing h.
The said casing h, is screwed upon and extends upward from the valve seat base B.
The sleeve d, properly fitted to the inner periphery of the case e, serves with such
case, not only to guide the valve in its vertical movements, but as a bottom to the
said case e, and thereby as a means of preventing the steam when escaping from
impinging against the spring and producing deposits thereon.
The sleeve d, is connected with the valve by a tapering or flaring neck k, that
constitutes a deflector of the steam, into the casing i, after the escape of such steam
from between the valve bearings a and b.
In the drawings of plate 2 (Figs 1 to 7 inclusive) the central steam induction
passage through the valve seat base B, is shown at as directly beneath the
valve bearing a, there being around and concentric with the passage l, another
induction passage m, by which steam is led from the boiler to the annular valve
bearing b.
Extending down from the hollow base B, is, what I term the guard pot C, which
is a cylindrical or other proper shaped pot open at top, and having in its sides
a series of holes n. This guard pot is to prevent the water in the boiler, when
suddenly foaming from being driven upward into and through the valve scat
base B; as it is liable to be at times, when the said base is without the said guard
or some device for the purpose.
Encompassing and screwed on the base B, is an annulus or gate D, which on
being screwed downward relatively to the outer ends of the passages o, opening
laterally out of the valve seat base, suffices to open such ends or passages more or
less, to intercept and regulate the egress of steam from them.
Leading downward from the valve seat are other passages p, that open into the
passages o, in manner as represented, each of such passages p being a cylindrical
hole, bored in the valve seat base B. In Fig 1 of plate 2, two ranges of such
passages are shown, while in Figs 3 and 4 but one range of them is represented in
the said base B. Extending upward from the said base and around each range P
is an annular rip q, or internal deflector, for deflecting steam from the next adjacent
valve seat upward into a downward external annular deflector r, projecting from
the valve A, in manner as represented, such deflector 7, encompassing the deflector q,
at a short distance from it. By means of the internal and external deflectors
and the steam on the valve being forced upward, will be deflected directly
downward upon the base, in a manner to aid by its reaction, in forcing the valve
upward.
q
Each valves annulus a or. b of the valve has within it and bounded by its inner
periphery, an opening x, for the escape of steam through such opening from the
valve seat, when the valve is raised from such, such opening being closed when the
valve is down upon the base B. With this construction of the valve the steam hias
a greater chance for escape than would be the case were the valve without any
such opening or openings. Were all the escaping steam to be thrown into the
deflector, the latter though performing its duty of aiding in forcing the valve
upwards, would operate to prevent the free escape of the steam, and therefore
by having within the valve an opening or openings x as described, much of the
steam as the valve may rise from its seat, can escape through the said opening

page_text: or openings, and the rest be utilized in acting within and from the deflector, as
described.
Instead of having the deflector », applied directly to the valve, it may be to the
valve seat base, as shown in Fig 6, in which part of the valve is exhibited at A,
the seat base at B, and the deflector at r, such deflector extending upward as shown
with respect to the periphery of the valve.
In this case the valve A is without any deflector q, but it may have one as
shown in Fig 7, of plate 2, in which case the base B should have extending from
it the upward deflector r. I allude to these arrangements of the deflectors as they
are but colorable changes, containing the principle of this invention.
The valve resting on its seat will be held down thereon by the spring f, against
the pressure of the steam in the boiler, to which the safety valve may be applied,
the tension or pressure of the spring on the valve being increased by screwing
downward the screw 8, over the head of the spring. The areas of the valve that
are directly over the passages and m, are what the steam pressure ordinarily acts
upon to overcome the resistance of the spring. The valve surface covering each.
seat, will not be so acted on, until the valve may rise from such seat.
When the pressure of the steam under the valve is sufficient to move the valve
off its seat, steam escaping will impinge against the tapering deflector k, in a
manner to aid rather than retard the escape of the steam from between the
deflectors and 1.
The steam will also cross the valve seats and be driven
downward through the passages 2, into the passages o, out of which it will escape,
the amount escaping being regulated by the ring D. As soon as the valve is forced
off its seat, the steam will be free to action a greater surface of the valve, than it
could when the valve rested on its scat, and consequently the valve will be forced
upward with an increased pressure, against the increasing power of its spring, as
the spring becomes contracted.
Having thus described the part or parts of this invention illustrated in Figs 1
to 7, inclusive of plate 2, I shall now explain the part or parts of the invention as
exhibited in Figs 8, 9, 10 and 11 of plate 2.
In such Figs 8, 9, 10 and 11 of plate 2, A. denotes the valve which is a compound
one it being composed of a disc or central part a, and a surrounding annulus b,
connected by radial arms 7, there being a space or opening x, between the said.
parts a and b, and concentric therewith. The valve has extended from it or from
its central part a, a guide stem 7, having radial wings u, to bear against the
periphery of the central passage f, of the seat base B, in order to guide the valve in
its vertical movements. Instead however of such a guiding device, I sometimes
use a guide sleeve provided with a tapering neck, and extended upward from the
valve into a cylindrical case surrounding the valve spring f
The valve spindle t, pivoted to the valve, is provided as usual, with the spring f
for forcing it downward, and there is around such spring a case e, that projects
upward from the base B, and is open at top, except in there being provided with
a stationary nut g, through which a screw h, for contracting the spring f¹, passes
and engages. The nut is held in place by a series of arms i, projecting from it to
the case e, all of which is common to various safety valves in use.
The valve sent base B, has in it a series of four passages o, radiating from the
lower part of the central passage f, and besides such central passage, there is
underneath the valve portion a, an annular passage 2, going down through the
base, such passages m and p being open at their lower ends, to allow steam from
the boiler or a pipe C, leading therefrom, to pass upward into and through the said
passages, and to the valve. An annular gate D, on the base, by being screwed
upward thereon, srves to cover or more or less uncover the outer ends of the
passages o, in order to regulate the escape of steam therefrom.
The valve virtually rests on four annular sents, concentric with each other, there
being two of them directly underneath the disc portion a, and two underneath the
ring portion b, of such valve. Such valve will be held down upon its seats by the
spring, the tension of which may be increased by screwing down the screw h.

page_text: The valve areas between the seats are what the steam pressure ordinarily acts on
to overcome the resistance of the spring. The areas directly covering tho seats,
will not be acted on by the steam, until after the valve may have risen from the
seats. When the pressure under the valve is nearly to the degree required, the
valve will open or risė rapidly and the steam will escape across the seats, part of
it going upwards through and across the valve, and the rest passing down the
central passage of the base B, and into and through the radial passages o, from
whence it will be deflected upward by the ring D.
On the valve rising, the extra surface of it exposed to the steam, will cause the
power to force the valve upward, to be suddenly increased, in order to overcome
the increasing resistance of the spring, as such spring may be contracted. This
sudden increase of power on the valve, will quickly force it upward against the
said increasing power of the spring and thus rapidly relieve the boiler of steam,
the valve subsequently slowly settling back upon its seats.
By raising the gate D so as to diminish the escape of steam through the central
part f, and the passages o, leading therefrom, the pressure on the valve may be
diminished, from which it will be seen that by such gate the said pressure may be
varied or diminished more or less, as occasion may require.
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 as of my invention, as represented in plate 1, is as follows, that is
to say-
-
1. The tubular valve seat base B, provided with the two concentric valve seats a
and b, the tubular hub c, and radial tubular arms d, arranged essentially as set
forth, in combination with the valve A, adapted to such base and hub, in manner
and to operate therewith substantially as represented.
2. The combination of the ring or gate C, secured on the base B, with such
base constructed in manner and to operate with the valve A substantially as set
forth.
3. The spring case or jacket F, having its upper part k, made tapering or conical
to deflect steam from it laterally to and through the openings of the crown of the
outer case D, all being substantially as and for the purpose specified.
4. The spring case or jacket F, provided with the tubular neck 2, extending
through the crown of the case D, as described, in combination with the tubular
screw H, screwed into the fixed arch piece I, and extending down through such
neck, to the cap plate h, of the spiral spring G, arranged within such case or jacket;
all being substantially as represented.
5. The spring case F, provided with the separable bottom g, fixed to the valvė
spindle E, and serving to support the spiral-spring G; all being essentially as
represented.
6. The combination of the spring case F, provided with the tubular neck i, with
the tubular screw H, and its supporting archi piece I, and with the valve spindle E
extending through such screw lengthwise thereof, and through the spring G and its
cap ; all being substantially as set forth.
7. The hood K, screwed on the case D, and with such, provided with the
perforated ears and with the perforated pin, arranged between such ears and in the
said case; all being substantially as represented.
8. The combination of the fastening screw f, with the case D, and the ring or
gate C, screwed on the base B, and to operate with the educts of the tubular arms,
as explained.
9. The combination of the tubular base B, having the two concentric valve
seats a and b the tubular hub c and arms d, with the valve A applied to such
seats and hub as described, and with the valve spindle E and its operative spring G,
cap h, necked jacket or spring case F,.tubular screw K, its supporter I, and the
case D; all being arranged and adapted substantially in manner to operate as
set forth.

page_text: I also claim as of this invention, as represented in Fig 1 to 7, inclusive of
plate 2, as follows, viz.
10. The valve A provided with the guiding sleeve d, extended upward within
the spring case e, and adapted to fit thereto and slide therein, substantially as set
forth.
11. The valve A, provided with the guiding sleeve d, having a closed bottom ki,
and extended within and fitted to the spring case f, substantially as set forth.
12. The compound valve A, provided with the concentric bearings a and b, and
the deflectors q and r, arranged essentially as set forth, in combination with the
valve seat base B, having the passages o, and p, and m, and the annular gate D,
substantially as specified or represented.
13. The combination of a guard pot C, having openings in its sides, and also
having a closed bottom as represented, with the safety valve and its seat base,
such pot being extended down from such base, as represented.
14. The valve provided with the downward deflector, in combination with the
valve seat base, having the upward deflector and the passages p, extending
therefrom downward into the passage o, provided with the gate D.
15. The valve A, provided with the guiding sleeve l, and tapering deflector A, the
said deflector constituting a bottom to such sleeve and the spring case.
16. The valve provided with the downward deflector r, in combination with the
valve seat base having the passages p, extending therefrom downward into the
passages o, provided with the gate D, as described.
17. The valve A having an opening or openings x, through it for the escape of
steam, and also having at its edge or periphery, a downward deflector 7, as
described, in combination with the base B, having a seat for and to close each
opening when the valve is resting on such base.
18. The open or compound valve A, and its seat B, provided with an upward
deflector, applied to the periphery of one of them, as set forth.
19. The open or compound valve A, and its seat B, provided with a downward
deflector adapted to the other; all being substantially as set forth.
I also claim as of this invention as represented in Fig 8, 9, 10 and 11 of
plate 2, as follows, viz:
20. The valve A, provided with central guide, the disc portion a, and the
concentric ring b, arranged and connected, essentially as described, in combination
with the valve seat base B, having the central and radial passages fand o, and
gate D, and also the two steam passages, m and p, concentric with the said central
passage, and arranged beneath the valve; all being substantially as specified and
represented.