IMPROVEMENTS IN SAFETY VALVES
Year: 1876

page_text: LETTERS PATENT to William Morgan-Brown, Engineer and Patent Agent, of
"
38, Southampton Buildings, County of Middlesex, for the Invention of
IMPROVEMENTS IN SAFETY VALVES." A communication from abroad by
S. Maurel and Charles Truel, Engineers, both of No. 5, Cité Trévise, Paris.
Sealed the 26th May 1877, and dated the 29th November 1876.
PROVISIONAL SPECIFICATION left by the said William Morgan-Brown at
the Office of the Commissioners of Patents on the 29th November 1876.
WILLIAM MORGAN-BROWN, Engineer and Patent Agent, of 38, Southampton
Buildings, County of Middlesex. "IMPROVEMENTS IN SAFETY VALVES."
These improvements in safety valves consist,―
Firstly. In adapting in a valve box a valve with a double seating separated by
a space which corresponds with an annular passage in the box below in communi-
cation with a nozzle open to the atmosphere, and in giving to the periphery of this
valve a cylindrical shape which fits into the box bored out cylindrically.
Secondly. In boring a central vertical hole through the said valve, in which is
inserted a round rod cut away at a certain part so as to present a triangular, squaro
or other polygonal section; this rod passes through the cover of the valve box,
which latter contains a cavity open to the atmosphere, and externally it is provided
with a weight corresponding to the pressure of the steam to be resisted. On the
bottom of such weight is placed a circular knife edge disc which rests on the said
cover when the steam in the boiler does not exceed its normal pressure, and on the
top of such weight is placed a similar knife edge dise which comes in contact with
a cross bar attached to the box when such pressure is exceeded, and thereby limits
the extent to which such rod with its weight rises. The part of the rod cut down to a
triangular or other polygonal shape commences at a short distance below the
bottom of the valve stem, and passes up entirely through the valve up to the bottom
face of the cover. Under these circumstances the steam can therefore rise through

page_text: the valve and exert its pressure on its upper surface, which being larger than its
under surface keeps the valve on its seating so long as the steam in the boiler does
not exceed its normal pressure, but when that pressure is exceeded it lifts the rod and
thereby in the first place closes the aperture in the stem by the rising therein of a
cylindrical portion of the rod from below, and allows in the second case the steam
situated above the valve to enter the cavity in the cover and from thence to be
discharged into the open air; this passage of the steam from the upper surface of the
valve to the open air is the consequence of the sectional part of the rod also rising and
establishing a communication between the two above-mentioned parts; directly
the upper surface of the valve is thus liberated by the steam the valve rises from
its double seating, allowing the steam from the boiler to escape down through the
annular passage in the box above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Morgau-Brown in the Great Seal Patent Office on the 26th
. May 1877.
WILLIAM MORGAN-BROWN, Engineer and Patent Agent, of 38, Southampton
Buildings, County of Middlesex. "1MPROVEMENTS IN SAFETY VALVES."
A com-
munication from abroad by S. Maurel and Charles Fruel, Engineers, both of No. 5,
Cité Trévise, Paris.
In order that the Invention be clearly understood I will proceed to describe
the same more fully conjointly with the five Figures of the two accompanying
Drawings, of which Figure 1 is an elevation in section of the apparatus; Figures 2
and 3, partial clevations of the same indicating two modifications in its con-
struction Figure 4, a partial elevation of another part of the apparatus, likewise
representing a modification; and Figure 5, a partial plan. In these Figures A
represents the improved valve provided on its under surface with two concentric
bearings B and C, resting on a seat provided with two corresponding concentric
bearings B and C pertaining to the valve box ; the interval between these two
latter form an annular chamber Q with a nozzel R, which communicates with the
atmosphere; the upper face of this valve a is also provided with a bearing or faced
scating D, which comes in contact with a similar face E on the under face of the
valve box cover El; this facing D serves to limit the rising of the valve the
cylindrical face of which slides easily on the cylindrical internal face t of the box F.
In the Drawing Figure 1 is shown a solid valve, but it may, if desirable, be pro-
vided with a spring segment like a piston or a metal cup, both of which would slide
'on the said inner face t of the box; H is the stem of the valve, it works easily in
the guide or cross G cast with the box, the flange V of which serves for attaching
the same to a boiler. The valve A is bored centrally through and through to
receive a central rod I which rests by a knife edge disc J on the cover E¹ of the
box; the part a, b, of this rod is cylindrical, the part b, d, triangular or of any other
polygonal section, and the remainder from d to g is cylindrical and of the same
diameter as a, b; at a this rod is provided with a flange M, with an under knife
edge J, having lateral orifices opening out in the atmosphere; the remaining upper
part of the rod is cylindrical and it is guided in a cross piece O, supported on
columns X; these latter parts serve more particularly as a protection to the central
rod. The cover E' is bored out at p and, and between these parts is actuated a
chamber which communicates with the atmosphere by one or more apertures S
P is a cock for discharging the condensed water from above the valve A; T is a
weight resting on the flange M, it serves as a load to the central rod I; the spaco

page_text: between the upper surface of this weight and the knife disk V¹ represents tho
stroke of the rod, and it equals the length of the bearing plus a certain sufficient
quantity to establish a communication between the under face of the valve and the
atmosphere. It will be understood that when the central rod rests on its knife
disc J the steam passes freely by the triangular part of the rod on to the upper
surface of the rod, whilst when this rod is pressed up against the knife disc V₁ the
steam is cuit off from this direction.
Action of the Apparatus. To facilitate this explanation I will suppose that the
section of the lower cylindrical part of the rod I is equal to two square centimetres,
and that the apparatus is to bo applied to a boiler with steam of five atmospheres
pressure; under these circumstances, the pressure on the rod will be equal to ten
kilogrammes, therefore to balance the same on its knife edged disc J its own weight
together with that of the balance weight T must be equal to ten kilogrammes; such
being the case, so long as the pressure of the steam does not exceed five atmospheres
these parts will remain stationary. In the Drawing it is shown that the steam
passes by the triangular section of the rod on the upper face of the valve and it
cannot escape its pressure on the valve is greater than under the valve; in the same
proportion as the entire upper surface of the valve exceeds the surface of its inner
surface calculated from the inner diameter of the facing B. If the pressure of the
steam rises above five atmospheres the rod I rises and its weight T comes in contact
with the cross O; under these circumstances the cylindrical part d, g, prevents the
steain from coming above the valve, and as the upper part will then be in com-
munication with the atmosphere the pressure exerted on the under face alone of this
valve causes it to rise, thereby, liberating the boiler from the excess of steam which
is discharged in the atmosphere through the nozzle R, after which the central rod
redescends, whereby the steam being once more admitted on the face of the valve
causes it to fall on its double seating, and so on.
•
The knife edge suspension of the central rod I is of considerable importance in so
much that it prevents any atmospheric adhesion which takes place when two faced
surfaces are in contact, whilst this particular system is susceptible of many modi-
fications, two of which are represented in Figures 2 and 3; in the former the said
rod is suspended at K by means of a conical shoulder, in the latter the rod is
swelled out at the part existing in the chamber p² and provided with a conical
shoulder above as well as below; the lower one acts the part of the knife disc J
and the upper one that of the similar disc V. When either of these two modifi-
cations are adopted no steam can escape at the lower shoulders, as might be the
case at the similar plan of the arrangement indicated at Figure 1, and when the
arrangement shown in Figure 3 is adopted the cross O and the pillars X
dispensed with.
.
may be
At Figure 4 is shown how the valve A may be provided with a metallic cup
packing as mentioned; in this case, when properly constructed the external facings
B and B of the valve and the box F respectively may be dispensed with.
Having thus explained the nature of the Invention, as well as the best means
that I am acquainted with for carrying the same into practice, I. claim as tho
Invention,
Firstly. The valve A with its double under facings B and C, cylindrical periphereal
edge, upper facing D, and central hole pierced through and through.
Secondly. A similarly constructed valve provided with a metallic cup packing on
its periphereal edge, as shown in Figure 4, giving rise to simplifications of con-
struction as above stated.
.
Thirdly: The box F with its corresponding double, facings B and C, annular
discharge chamber Q, and discharge nozzle R.
Fourthly. The cover E with its chamber 27 and lateral discharge S.
Fifthly. The central rod I subdivided in cylindrical and triangular or other
polygonal shaped sections, lower and upper knife edged discs and V₁ and
weight T.

page_text: And, Sixthly. The modifications of the said rod I, as above explained and illus-
trated in Figures 2 and 3.
In witness whereof, I, the said William Morgan-Brown, have hereunto set
my hand and seal, this Twenty-sixth day of May, in the year of our Lord
One thousand eight hundred and seventy-seven.
WILLIAM MORGAN-BROWN. (L.S.)