IMPROVEMENTS IN SAFETY VALVES AND IN THE APPARATUS OR MEANS CONNECTED THEREWITH."
Year: 1877

page_text: LETTERS PATENT to Thomas Black, of Liverpool, in the County Palatine of
Lancaster, for the Invention of "IMPROVEMENTS IN SAFETY VALVES AND IN
THE APPARATUS OR MEANS CONNECTED THEREWITH."
PROVISIONAL SPECIFICATION left by the said Thomas Black at the Office
of the Commissioners of Patents on the 14th March 1877...
.
THOMAS BLACK, of Liverpool, in the County Palatine of Lancaster. "IMPROVE-
MENTS IN SAFETY VALVES AND IN THE APPARATUS OR MEANS CONNECTED
THEREWITH."
This Invention which relates to certain improvements in safety valves and in the
apparatus or means connected therewith is applicable not only to safety valves for
steam boilers, but to safety valves applied to other vessels, pipes, or conduits which
contain liquids or fluids under pressure.
The essential feature of the new or improved valve consists in this; viz., that the
area of steam supply from the boiler is always greater than the area of the steam
escape from the valve, the result of which construction is that at the instant of
opening, the area of the valve face being increased from that instant, the steam
acting upon this enlarged area from an orifice greater than that through it escapes
from the valve, exercises by virtue of the difference of area of their orifices a greater
total pressure upon the valve, and thereby obtains an increased control in opening
or lifting the valve against its load.
The increased control herein-before referred to is obtained by constructing the
valve with a deep lip all round its periphery which dips or hangs down some
distance over the valve seat. The valve seat may have a conical exterior and the
inner side of the lip parallel, or vice versa, the valve seat may have a parallel
exterior, and the inner side of the lip conical or the exterior of the valve seat, and
the interior-of the lip may both be conical or both parallel; but when both parallel,
their action is less perfect than with the other form.
By either of these arrangements of the valve seat and lip, the steam, after
escaping over the valve seat and becoming to some extent confined between the lip
and the valve seat, is caused to exercise the increased pressure which will lift the
Price 10dl
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page_text: valve until the area of the steam escape from the lip is equal to the area of the
steam orifice over the valve seat.
The orifice, the upper part of which constitutes the valve seat, niay be parallel
inside, but is preferably constructed conical, that is to say, increasing in diameter
from the throat outwards.
In order to prevent the steam, when the valve is blowing off, from getting up into
the chamber which contains the spring or springs of spring-loaded safety valves,
and thereby through heating the spring or springs injuring their elasticity, the back,
that is to say, the top of the valve is formed with a lip surrounding the spindle and
projecting upwards. When the valve is opened this lip is forced against a bush or
guide in the valve casing through which the spindle passes, and the surfaces of the
edge of the lip and the under side of the bush or guide being ground or scraped, so
as to fit against one another steam-tight, do, at the instant the safety valve is
raised, prevent the steam from getting up into the casing containing the spring or
springs.
In place of forming this lip or stop valve in the manner now last described so as
to project up from the safety valve, it may be formed on the under side of the bush
or guide so as to project downwards therefrom, in which case a portion of the upper
surface of the safety valve is ground or scraped to fit steam-tight against it.
The new or improved valve besides being used as a safety valve proper, may also
be used as an easing valve in combination with the steam-loaded safety valves,
for which Letters Patent have been granted to the said Thomas Black, No. 1632,
A.D. 1876.
Another improvement in connexion with safety valves consists in forming springs
of flat steel, and in place of being wound into a spiral the bar or flat steel is doubled
over and redoubled upon itself in several flat layers at any desired distance apart.
Any required number of such springs may be applied to a safety valve by being
laid vertically together inside a box or guide which rests upon a shoulder on the
valve spindle, and the pressure of which upon the valve is produced by means of
bolts passing through a cap or box which rests upon the upper ends of the springs.
The lower ends of these bolts passing through the valve casing, and being provided
with nuts, on tightening or loosening them the requisite pressure is obtained. This
same arrangement for producing the pressure of the springs upon the valve is
applicable to the ordinary spiral springs; such springs are more stable and more
elastic than the spiral springs commonly used.
Another part of the present improvements relates to the setting, adjusting, and
testing the springs of safety valves. This consists in applying a spring balance for
setting the spring with any required load without steam in the boiler, it being also
capable for testing the spring and checking the steam gauge. In order to test the
springs, they are first tightened by drawing down the cap by the nuts on the screw
bolts which pass through the lower part of the casing, until what is supposed to be
the required pressure is obtained. To ascertain if this pressure is correct and
without the necessity of getting up the steam in the boiler, the spring balance
which is connected by a lever to the upper part of the valve spindle is tightened
until the desired pressure corresponding to the area of the safety valve is indicated,
as marked by the position of the pointer on the scale of pressures or weights upon
it. When this point is reached, and if the safety valve spring has been screwed
down to the proper amount corresponding to the pressure, then the spring balance
and the safety valve springs should be in equipoiso, so that the tension of the spring
balance should slightly move the lever, or in other words open the valve. If not
in equipoise then the nuts on the bolts of the holding-down cap must be tightened
or loosened accordingly, and as indicated by a pointer attached to the lever.
In place of using a spring, balance weights may be applied to the outer end of the
balance lever, and the spring screwed down until the pointer on the lever, by
assuming a central position, indicates that the proper pressure has been reached.
In order to test the accuracy of the spring and steam gauge when the steam is up
in the boiler, the following example is given-Supposing the case of a safety valve,..

page_text: 3 inches in diameter, which has an area of 7.0686 square inches, and the boiler
pressure 60 lbs. per square inch. In this case it will be necessary to reduce the
weight on the outer end of the balance lever to 354 lbs., and get up steam in the
boiler to 10 lbs. pressure on the steam gauge, which multiplied by 7.0686 square
inches area of the safety valve equals 70-6860 lbs., added to 354 lbs. on the end of
the balanced lever equals 424-6860 lbs. pressure on the valve, which ought to rise if
the steam gauge is correct. But to test the accuracy of the spring and steam gauge
still further the weights on the outer end of the balanced lever must be reduced
to 60 lbs. The steam pressure in the boiler must then be increased to 51/2 lbs.
pressure on the steam gauge, which multiplied by 7-0686 square inches area of the
safety valve equals 364-03290 lbs., added to 60 lbs. on the end of the balanced lever
equals 424.03290 lbs. total pressure on the valve, which ought to rise if the steam
gauge is correct, and the pointer on the balanced lever will indicate the same by
falling back to the dotted line.
When it is necessary to set or test the springs the ordinary lever for easing the
valve may be removed and the balanced lever or beam substituted. The balanced
lever may then be adjusted at the inner end to the valve spindle by means of a
screw centre. The weights or spring balance may then be applied to the outer end
and the spring tempered by the bolts and nuts.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
.
by the said Thomas Black in the Great Seal Patent Office on the 13th September
1877.
THOMAS BLACK, of Liverpool, in the County Palatine of Lancaster, England.
"IMPROVEMENTS IN SAFETY VALVES AND IN THE APPARATUS OR MEANS CONNECTED
THEREWITH."
My said Invention relates to certain improvements in safety valves and in the
apparatus or means, connected therewith, and is applicable not only to safety valves
for steam boilers but to safety valves applied to other vessels, pipes, or conduits
which contain liquids or fluids under pressure, but for the sake of simplicity and
convenience of description I herein explain it as applied to a steam boiler.
In a valve constructed according to my said Invention the area of the orifice
through which steam acts upon it from the boiler is always greater than the area
of the orifice through which the steam escapes from the valve to the atmosphere, and
from the means I employ as herein-after described to contract the area of escape
to the atmosphere it results that at the instant the valve opens or rises from its
seat the steain exercises by virtue of the contraction of the orifice of its escape a
greater total pressure upon the valve than it would do if not so contracted, and the.
steam thereby obtains an increased control in opening or lifting the valve against
its load. This increased control is obtained by constructing the valve with a deep
lip all round its periphery, which dips or hangs down some distance round the
exterior of the valve seat, the steam escaping over the valve seat and becoming to
some extent confined between this lip and the valve seat, is caused to exercise the
increased pressure herein-before mentioned. The valve seat may have a conical
exterior, and the inner side of the lip may be parallel with the axis of the valve, or
vice versa, the valve seat may have a parallel exterior, and the inner side of the lip
conical, or the exterior of the valve seat and the interior of the lip may both be
conical or both parallel; but when both parallel their action is less perfect than with
the other forms.
In order to prevent steam, when the valve is blowing off, from passing up into
the chamber containing the spring or springs of spring-loaded safety valves, I form
on the top of the valve another lip surrounding the valve spindle, and projecting
upwards, which lip, when the valve is opened, is forced against a scat formed on

page_text: the lower bush or guide in the valve casing through which the valve spindle passes,
thereby closing any opening or space between the valve and spindle and its guide
through which steam might pass.
I form the spring of spring-loaded safety valves of flat steel bent over and
redoubled upon itself in several flat layers at any desired distance apart. Any
number of these springs may be applied to a safety valve by being laid vertically
together inside a box or guide, the lower ends of the springs resting upon a shoulder
on the valve spindle, the pressure of the said springs upon the valve being regulated
by means of bolts passing through the cap or box which rests upon the upper ends
of the springs. The lower ends of these bolts pass through the valve casing, and
are provided with nuts, on tightening or loosening which the requisite pressure is
obtained. I use a spring balance, as herein-after described, for setting the spring
with any required load without steam in the boiler. The springs are first tightened
by drawing down the cap by the nuts on the screw bolts which pass through the
lower part of the casing until what is supposed to be the required pressure is
obtained. To ascertain if this pressure is correct without getting up steam in the
boiler, the spring balance (which is connected by a lever to the upper part of the
valve spindle) is tightened until the desired pressure corresponding to the area of
the safety valve is indicated as marked by the position of the pointer on the scale
of pressures or weights upon it. When this point is reached, and if the safety valve
spring has been screwed down to the proper amount, corresponding to the pressure,
then the spring balance should be in equipoise, so that the tension of the spring
balance should slightly move the lever, or in other words, open the valve. If not
in equipose then the nuts on the bolts of the holding down cap must be tightened
or loosened accordingly, and as indicated by a pointer attached to the lever.
Weights may be used in place of the spring balance.
And in order that my said Invention may be properly understood, I now proceed
inore particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
annexed Sheets of Drawings, and to the letters and figures marked thereon, that is
to say :-
Figure 1 represents a side elevation; Figure 2, a vertical section; and Figuro 3,
a plan partly in section on the line 1, 2, Figure 2, of a safety valve constructed
according to one modification of my Invention. A part of a boiler to which the
valve may be fixed is marked A; the valve spindle, B; the steam inlet from the
boiler to the valve, C; and the steam outlet from the valve, D. In the stean inlet
C the valve scat E is fixed, and upon the lower end of the valve spindle B the
valve F is formed, having a deep lip f around its periphery, which dips or hangs
down some distance over the exterior of the valve scat E. The inner side of the
lipfis in this arrangement shown of an inclined or conical formation, and the
upper part of the interior of the valve seat E is also inclined, gradually widening to
its upper part, iminediately under the valve.
The valve spindle passes up through the box G, containing the spring H, for
loading the valves. This spring bears at its lower end, upon the flanch or projecting
ring b on the valve spindle, and at its upper end it is seated in the adjustable box
or cap I. This cap I has at its side guide pieces or wings i, through the lower of
which bolts pass, these extending down through the valve case, and being
furnished at the exterior of the case with set and lock nuts, by tightening or
loosening which the cap I may be lowered or raised, and the spring H compressed
or allowed to extend, and consequently the load on the valve F is increased or
diminished as may be required. The valve F has at its upper part or back a lip f¹
surrounding the spindle and projecting upwards; when the valve is opened this lip
is forced against the bush or guide g in the valve casing. This lip f¹ and the under
side of the bush g being ground or scraped so as to fit truly against one another
when the valve is blowing off, close steam tight against each other and prevent
the steam from passing up into the box G and from injuring the spring by
heating it.

page_text: In place of forming this lip or stop valve in the manner described and shown at
Figure 2, the lip may be formed on the under side of the bush or guide g, in which
case it bears when the valve is blowing off upon the back of the valve F, which at
that part is ground or rasped to fit steam-tight against it. The valve F may, when
it is considered necessary, be raised from its sent by hand by operating the lever J,
and the top of the valve spindle B is furnished with wings or handles b², by which
the valve may be turned upon its seat when necessary for grinding it.
Figures 4 and 5 are sections at right angles to each other, and Figures 6 and 7,
plans partly in section of a safety valve, similar in general construction to that
herein-before described and illustrated at Figures 1, 2, and 3, and similar parts on
these Figures are marked with the same letters of reference; but I have shewn
applied to this safety valve, illustrated by Figures 4 to 7, my improved flat loading
spring K. In place of being wound into a spiral the bar of steel is bent over and
redoubled upon itself in several flat layers at any desired distance apart. Any required
number of these springs may be applied to a safety valve; in the Drawing I have
shewn the application of two; they are retained in position by the studs or screw
heads k, or their equivalents, and by the projections 2 on the lower bearing ring b,
and their pressure or stress upon the valve is increased or diminished through the
screw bolts i¹, in the same manner as is that of the spring H (in Figures 1, 2, and 3).
These flat springs are more easily constructed, and therefore less costly than are
spiral springs. The valve and valve seat shewn in Figuro 4 are of a slightly
different form from those illustrated in Figure 1, the valve being furnished with a lip
parallel or cylindrical on its inner surface, the valve seating being at its upper part
of inclined or conical formation on both its inner and outer sides.
Figures 8, 9, and 10 represent vertical sections of steam-loaded safety valves
constructed according to the Invention for which Letters Patent were granted to
me on the 19th April 1876, and Numbered 1632, but to the casing valve and relief
valve, of which the deep lip constructed according to my present Invention is shown
applied. In these Figures the steam-loaded safety valve proper is marked L; the
easing valve L'; and the relief valve M.
In Figure 8 the relief valve is loaded by the spring balance N, and in Figures 9
and 10 it is loaded by a vertical spiral spring, but weights may be substituted
direct or by lever when occasion requires.
Figure 11 represents a vertical section of the deep-lipped valve loaded directly
by a spiral spring, in which the valve lip is shewn conical, as herein-before
described.
In Figures 8, 9, 10, and 11, the stop valve 8, which fits close to the back of the
valve when steam is blowing off, prevents the steam from passing up to and injuring
the spring, as berein-before described with reference to the preceding Figures. The
studs or bolts and nuts marked u are for securing the cap P. The cap P is for
holding down the spring. The lever T is for lifting the valve from its seat when
occasion requires. The winged handle R. and spindle and socket S are for turning
round the valve upon its seat, and for grinding it when occasion requires.
In Figures 8, 9, and 10 the lever T and the winged handle R, and spindle and
socket S, are shewn applied to the steam-loaded safety valve.
The relief valves and the easing valves in Figures 8, 9, and 10 are formed
according to my Invention, that is to say, the valves have deep lips encircling the
exteriors of the seatings. The lip (marked ) of the easing valve I have shewn in
Figure 8 as having its inner surface parallel with its axis, as is also the exterior of
the valve seating. In Figures 9 and 10 the lip is of slightly conical formation on
its inner surface, and the exterior of the valve seating is parallel with its axis. The
lip (marked f) of the relief valve in Figure 8 is of conical formation on its inner
surface, and the exterior of the valve seating is parallel with its axis. In Figures 9
and 10 the lip fis conical on its inner surface and the exterior of the valve seating
is also of conical formation. By means of the levers, marked T in Figures 8, 9,
and 10, the valves may be raised by hand, to ascertain that the said valves are in

page_text: working order. The wings or handles R are for turning the valves upon their seats
when necessary for grinding them.
In the several Figures of the annexed Drawings I have shewn the inside of the
upper part of the steam inlet to the valve which constitutes the valve seat, as being
conical or flaring, that is to say, increasing in diameter from the throat outwards,
which form I prefer; but it may, if desired, have its interior surface parallel with
its axis.
By the use of the deep lipped valve, herein-before described, the area of the valve
face presented to the steam increases as the valve lifts, and the steam acting upon
this enlarged area which is greater than the area of the orifice through which it escapes
from the valve, exercises, by virtue of the difference of areas which the deep lip
produces, a greater total pressure upon the valve, and thereby obtaining for the
steam an increased control in opening or lifting the valve against its load.
In Figure 1 I have shewn my application of a spring balance for setting the
spring of spring-loaded safety valves with any required load without steam in the
boiler, it being also available for testing the spring and checking the steam gauge.
In order to set the springs, they are first tightened or compressed by drawing down
the cap I, by the nuts, on the screw bolts i¹, until what is supposed to be the
required pressure is obtained. To ascertain if this pressure is correct, I employ the
spring balance O, which is connected to one end of a lever P, turning on a fulcrum p
on the valve case, the other end of the said lever bearing against a collar b² on the valve
spindle. The spring balance is tightened until the desired pressure corresponding to
the area of the safety valve is indicated, as marked by the position of the pointer
on the scale of pressures or weights upon it. When this point is reached, if the
safety-valve spring has been screwed down to the proper amount, corresponding to
the pressure, the spring balance and the safety-valve springs should be in equipoise,
so that the tension of the spring balance should slightly move the lever and open
the valve. If not in equipoise, the nuts must be tightened or loosened accordingly
and as indicated by a pointer 2 attached to the lever. In place of using a spring,
balance weights may be applied to the outer end of the balance lever, and the
Bufety-valve spring screwed down until the pointer p¹, by assuming a central
position, indicates that the proper pressure has been attained.
In order to test the accuracy of the spring and steam gauge when the steam is
up in the boiler, the following example is given :-Supposing the case of a safety
valve, 3 inches in diameter, which has an area of 70656 square inches, and the
boiler pressure 60 lbs. per square inch. In this case it will be necessary to reduce
the weight on the outer end of the balance lever to 354 lbs. and get up steam in
the boiler to 10 lbs. pressure on the steam gauge, which, multiplied by 7'0686 square
inches area of the safety valve, equals 70-680 lbs. added to 354 lbs. on the end of
the balanced lever, equals 424-686 lbs. pressure on the valve, which ought to rise if
the steam gauge be correct. But to test the accuracy of the spring and steain
gauge still further, the weights on the outer end of the balanced lever must bo
reduced or increased, say, for example, to 60 lbs. The steam pressure in the boiler
must then be increased to 51/2 lbs. pressure on the steam gauge, which, multiplied
by 7.0686 square inches area of the safety valve, equals 364-0329 lbs., which, added
to 60 lbs. on the outer end of the balanced lever, equals 424-0320 lbs. total pressure
on the valve, which ought to rise if the steam gauge is correct. From the fore-
going examples others will be obvious to the practical engineer of applying the
means now last described for the tests set forth.
Although I have described my improvements as applied to the safety valves of
steam boilers, yet it will be readily understood without further description that they
may also be applied to safety valves for other vessels, or pipes, or other receptacles
or conduits containing or conducting liquids or fluids under pressure.
Having now described and particularly ascertained the nature of my said Inven
tion, and the system, mode, or manner in or under which the same is or may be
used or practically carried into effect, I would observe in conclusion that what I

page_text: consider to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,-
First. The safety valves hercin-before described and shewn upon the annexed
Sheets of Drawings, in which the essential feature is the deep lip projecting down
over the valve seat, in the manner and for the purposes set forth, either for simple
safety valves or as applied to the relief and easing valves of the steam-loaded safety
valves, described in my Specification, No. 1632, A.D. 1876.
Second. Forming on the back of safety valves or on the guide or bush above such
valves a projecting lip, which, when the valves are lifted by the steam, makes a
steam-tight enclosure around the opening through which the valve spindle passes
from the loading-spring box, thereby preventing steam from entering the said spring
box, essentially as herein-before described and illustrated in the accompanying
Drawings.
Third. The improved construction of spring for spring-loaded safety valves, that
is to say, forming the said spring of flat steel bent over and redoubled upon itself
in several flat layers at any desired, distance apart, essentially as herein-before
described and illustrated in Figures 4, 5, 6, & 7 of the accompanying Drawings.
Fourth. The arrangement for tightening or compressing the spring or springs of
spring-loaded safety valves, consisting of a cap against which one end of the spring
bears, the said cap being capable of being raised or lowered by bolts and nuts, thus
causing the other end of the spring to bear with a greater or less force upon a pro-
jection on the valve spindle, essentially as herein-before described and illustrated in
the accompanying Drawings.
Fifth. The arrangement, substantially as herein-before described and shewn upon
Sheet 1 of the Drawings, for setting safety valves without the necessity of getting
up steam in the boiler; also, for testing the accuracy of the load spring and the
steam guage when steam is up in the boiler.
In witness whereof, I, the said Thomas Black, have hereunto set my hand
and seal, this Tenth day of September, One thousand eight hundred and
seventy-seven.
THOMAS BLACK. (L.S.)