Note: Descriptions are shown in the official language in which they were submitted.
I ~o73888 ~:
1 VALVE
Description of the Prior Art and the Present Invention
This invention relates to valves and more particularly
to diaphragm seated eccentric ball valves for use in cryogenic
applications and similar high pressure applications.
High pressure butterfly valves for use in cryogenic
applications are known in the art. One such valve is
disclosed in U. S. Patent No. 3,260,496. This prior art
type valve utilizes a disc having a spherical surface arranged
in an offset relationship with the sealing means for providing
zero leakage. The butterfly element of a butterfly valve !
exhibits high pressure drops in high pressure applications
resulting in the need to construct the butterfly element
relatively thick. Butterfly valves are generally usable at
line pressures in the range of 300 lbs. Other prior art
valves employing spherical seals and/or spherical valve
eiements are disclosed in U. S. Patent-Nos. 2,809,011;
2,015,849 and 125,7~2. These patents also disclose the
feature of disposing a portion of a valve member on an
offset center for producing a tight sealing relationship.
Ball type valves are also known in the art. Floating
-ball valves are subject to high loads and excessive wear in
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normal service. Prior art hall valves generally require complex
actuating mechanisms to accomplish unloading of the valve seat
before the rotation in a manner to protect the plastic seals
from premature failure. In a floating or semi-floating ball
valve, the valve seats support the ball and the line pressure
urges the ball to contact a statlonary metal seal. ~all valves,
as distinguished from butterfly valves, exhibit low pressure drops
and may be used in the pressure range of 600-2500 lbs. In
cryogenic applications, sliding seals have been found to be very
unreliable. Accordingly, at the present time there is a need for
an improved valve having a tight shutoff in high pressure
applications.
In accordance with the present invention there is
provided a valve comprising:-
a body having a passageway for fluid;
an apertured ball having spherical sealing surfaces and
being rotatable about an eccentric pivotal axis, the spherical
sealing surfaces being offset from the axis and the spherical
sealing surfaces on opposite halves of the ball being offset on
opposite sides of the axis whereby each spherical sealing surface
of the ball moves on an eccentric arc as the ball is rotated;
trunnion means for rotatably supporting the ball within
the body to allow the ball to be rotatably positioned within
; the passageway for controlling flow of fluid;
respective sealing means mounted on the body on opposite
~ides of the ball for sealing coaction with the spherical sealing
surfaces, each sealing means comprising dynamic sealing means
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carrying primary resilient sealing means for engaging the ball so
as to provide tight valve shutoff, and the dynamic sealing means
comprising a flexible diaphragm mounted on the body and mounting
the primary sealing means for coaction with the spherical sealing
surfaces of the ball, and means for securing the diaphragm to the
body and for preloading it to render, in use, the upstream
diaphragm responsive to upstream pressure so as to allow the ball
sealing means to move towards the ball when a higher line pressure
prevails in the passageway; and
means coupled to the trunnion means for rotating the ball
so that each spherical sealing surface moves on its eccentric arc
away from the sealing means at each side of the body without
scuffing and deforming the sealing means.
Thus, the present invention is able to provide an improved
13 bi-directional, eccentrically mounted ball valve having spherical
surfaces exhibiting minimum wear of the seats, a relatively long
service life and particularly in applications wbere the valve
must be opened to sustain high differential pressures relative
to similar prior art valves. The ball of the ball valve of
the present invention is trunnion mounted as distinguished from
the floating or semi-floating ball valves of the pxior art and
coacts with dynamic and static sealing arrangements for providing
tight shutoff including at cryogenic temperatures. The valve of
the present invention includes a pressure sensitive seal con-
structed and defined to urge the seal against the ball. Thevalve structure includes a fire-safe sealing feature providing
reasonably effective shut-off in the event of fire.
~ 1073888
¦ In such a valve the securing means may include means for
1 ¦ preloading the diaphragm at a given tension to cause it to
¦ function as a spring to provide an initial seating force for the
¦ resilient sealing means for tight valve shutoff at a lower line
¦ pressure in the passageway. The securing means may also include
s¦ means for maintaining sufficient seating forces for the primary
¦ sealing means in response to changes in temperature,
These and other features of the present invention may
be more fully appreciated when considered in the light of the
l following specification and drawings, in which:
Fig. 1 is a cross-sectional view, with portions in
elevation, illustrating the ball valve embodying the present
invention;
Fig. 2 is a side elevational view of the valve of Fig. l;
Fig. 3 is an enlarged cross-sectional vie~ of the
lS detailed area taken around the line 3 of Fig. l;
Fig. 4 is an enlarged cross-sectional view of the detailed
area taken around the line 4 o~- Fig. l;
Fig. 5 is an enlarged cross-sectional view of ~he detailed
area taken along the line 5 of Fig. l;
2 Fig. 6 is a diagrammatic illustration of the ball and
sealing elements of the valve of Fig. 1 illustrating the
eccentric action of the ball;
Fig. 7 is a detached, top plan view of the seal retainer
element for the valve illustrated in Fig. l;
Fig. 8 is a partial sectional view take~ along the line
8-8 of Fig. 7; and
Fig. 9 is a partia7, sectional view taken along the
line 9-9 of Fig. 7.
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1073888
1 Now referring to the drawings, the improved valve 10
of the present invention will be described in detail. The
valve 10 comprises a body 11 having a fluid passage 12 defined
therein. The valve control element comprises an apertured
5 ball 13 having a central aperture 13A which has a diameter
approximately the same as the internal diameter for the fluid
passageway 12 and the associated piping coupled thereto ~not
shown). The ball control element 13 coacts with sealing
means 14 which comprises a primary, static sealing means
14S and a secondary, dynamic sealing means 14D. The dynamic
sealing means 14D mounts the static sealing means 14S which
coacts with the operative sealing surfaces of the ball
element 13~ as will be examined in more detail hereinafter.
The ball element 13 in accordance with the present invention
is trunnion mounted at the top and the bottom by means of
the trunnion elements 13T and 13~ constructed integrally
with a ball l3 proper, as illustratedO The top trunnion
element 13T is coupled to a control shaft 24 which is in
turn coupled with a control wheel in a conventional fashion
for controlling the position o the shaft 2~ and thereby the
position of the ball 13 within the fluid passageway for
controlling the flow of the fluid.
One of the important features of the present invention
is the construction of the ball element 13 and in particular
the construction and arrangement of the operative sealing
surfaces thereof.~ The ball l3 is provided with sealing
surfaces that are defined as a spherical surface for coacting
with the sealing means 14. A diagrammatic representation
of the construction and arrangement of the ball element 13
is illustrated in F;g. 6 for purposes of explanation.
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1¦ The ball element 13 is illustrated in Fig. 6 looking down
onto the top of the ball and with the ball arranged in a
fluid passageway in a closed position. The operative sealing
surfaces of the ball element 13 are shown in sealing
relationship with the seals 14. Viewing the ball 13 down
from the top, the right hand spherical radius of the ball
13 is offset above the normal center line or above the pivot
point P for the ball. Similarly, the left hand spherical
radius is offset below the normal center line or pivot point
P. The ball 13 is constructed so that the offsets function
in the illustrated plane only. Side planes for the ball 13
are deined on the ball intermediate the spherical surfaces 1,
and are arranged on the normal centerline for the ball. In
this arrangement, the seals 14 are in sealing relationship
with the spherical surfaces 13S for the ball 13. When ~he
seal 13 is installed into the valve body 11, a rotation of
the ball 13 in a 90 degree counterclockwise turn by means of
its control element is necessary to align the ball aperature
13A with the fluid passageway 12 of the valve body 11.
2 During this control operation the ball 13 will rotate on
the pivot point P and as it rotates both spherical halves -
of the ball 13 will operate on an eccentric arc away from
the seals 14 on each side thereof. ,The arrangement of the ¦
ball 13 so that it traverses an eccentric arc eliminates seal
scuffing and deformation and renders t~e valve 10 bi-
directional. The ball element 13 is illustrated in the
same closed relationship in Fig. 6. i
The sealing means 14 is mounted on the fluid body 11
; adjacent the operative sealing surfaces 13S or the ball
301 e ent 13. m e sealing means 14 romprises the primary,
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1 ¦ static sealing element ~ ; see Fig. 3. The dynamic sealing
¦ element 14D comprises a diaphragm-like metall c se~l~
retainer 14D mounted upstream,sF~f'~ from the
I primary static seal 14S. The over-all construction of the
51 diaphragm seal retainer 14D is best illustrated from ,
¦ examining Figs. 7-9. The seal retainer 14D mounts a static
seal 14S at one end for sealing coaction with the operative
sealing spherical surface 13S for the ball 13. The seal
14S may be constructed of any conventional material such
as plastic or the like in accordance with the particular
application of the valve 10. For cryogenic applications the
B seal 14S may be constructed of a Teflo~r~ as ~. The outer
surface 14SS for the seal 14S is angularly defined relative
to the coacting spherical surface of the ball 13S to provide
a tight sealing relationship'therewith when placed in
engagement therewith as illustrated in Fig. 1. Associated
with the seal retaining'element 14D is a locking collar 15
l mounted to the body 11 for securing the element 14D to the
i body 11. The locking collar 15 is defined to also secure -
, 20 the cealing element 14S to the element 14D in the seal
retaining socket 14SR thereof. ~The locking collar 15 is
arranged to abut the section of the element 14D having a ,,
~, reduced thickness for securing it t,o the valve body 11 and
to overlie the'top section of the seal 14S. A Teflon strip
25 16 is provided in a recess defined in the top of the '~,
retaining element 14D intermediate its ends for sliding ~ ''
~, engagement witht~e bottom surface of the locking collar 15,
as best illustrated in Fig. 3. A loading ring 17 mounting
a set screw 18 secures the locking ring 15 and thereby the
30 ll seal ta;ning element 14D to the valve body 11. The loading
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1 1073888
1 ring 17 is arranged with a retaining ring 19 mounted between
the outer surface of the loading ring 17 and the adjacent
surface of the valve body 11. This arrangement allows the
seal retaining element 14D to be preloaded so that a certain
amount of tension is provided on the diaphragm seal retaining
element 14D and thereby~a certain amount of tension on the
primary seàling element 14S. This also renders the diaphragm
sealing element 14D responsive to the upstream line pressures
prevailing in the fluid passageway 12. As a result of the
prevailing pressures in the fluid passageway 12 with wh;ch
the valve 10 may be used, the seal retaining element 14D will
move towards and away from the operative sealing surfaces 13S
; for the ba~l 13 to place the primary sealing surface 14SS
of the seal 14S in sealing coaction therewith. In a normal
high pressure application of the valve 10, the upstream
pressure may be 2160 pounds per square inch which is sufficient - -
to al~ow the metallic diaphragm 14D to ~e responsive thereto.
~ ig. 4 illustrates the detailed arrangement of the upper
trunnion 13T, the valve body 11 and the ball element 13.
The trunnion 13T is provided withz trunnion bushing 13TB
completely surrounding the trunnion 13T and extending to the
adjacent surface of the ball ~ement 13. A shim 20 is mounted
in engagement with the body 11 and pver a thrust washer 21
arranged in engagement with t~.e adjacent surface of the ball
element 13~ The lower trunnion 13B is similarly arranged.
This arrangement is illustrated in Fig. S wherein a trunnion
bushing 13BB is illustrated completely surrounding the trunnion
13B and a shim 20 and a thrust washer 21 are arranged
intermediate the valve body 11 and the adjacent surface of
the ball element 13.
1073888
1 The remaining structure for the valve 10 consists of a
control shaft 24 coupled to the upper trunnion 13T immediately
above the bushing 13TB in a conventional relationship for
controlling the position of the ball 13. The control shaft
5 24 is coupled in the usual fashion with a control wheel 15
for rotating the control shaft 14 and th-ereby the ball 13
in the fluid passageway 12. The valve body 11 is provided
with a cover 22 which allows the valve 10 to be fully top
loaded. The cover 22 is mounted to the valve body 11 and
is secured by means of conventional fasteners such as the
fastener ~3 illustrated in Figs. 1 and 2. Upon removing
the fasteners 23 from the valve body 11, the cover 22 may be
completely removed thereby exposing the internal structure
of the valve body 11 and the ball 13 mounted therein. This
allows all of the internal paxts and elements o~ the valve 10
to be readily removed and services without the necessity of
having to remove the valve body 11 from the associated
pipelines.
In the construction of the v~lve 10 of the present
invention, the sealing arrangement employing the flexible,
secondary sealing element 14D allows the sealing means 14 to
; move into and away ~rom the ball 13 without the necessity for
sliding seals. It will be recognized ~y those skilled-in
the art that sliding seals have been found to be unreliable,
particularly in cryogenic applications. The sealing retaining
element 14D additionally functions as a spring to provide
the initial seating force for the primary seal 14S for
providing a tight shutoff condition at the lower line pressures.
At the higher line pressures, tight shutoff is provided as
a result of the seal retaining elementl4D providing additional
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1 1073888
1 ¦ seatlng forces due to its being responsive to the upstream
line pressures which cause it to move toward the ball 13 and
place the primary seal 14S in a tighter seal~ng relationship
with the operative sealing surface 13S of the ball 13. This
advantageous function results through the provision of a
thin, flexible section 14DT for the seal retaining element
14D which is backed up or~.,is abutted by the adjacent surface
of the locking collar 15. This.arrangement of the secondary
sealing structure causes the element 14D to be responsive to
the upstream line pressure and as the pressure builds up and
the diaphragm action of the element 14D causes it to contact
the adjacent surface of the ring 15, this allows the diaphragm
stresses to be maintained within allowable limits at the
higher differential pressures.
Other important aspects of the use of the secondary sealing
arrangement disclosed.by the present invention is that the
se.condary metal element 14D provides seating in both directions ~
for effective valve shutoff in the event of a fire. In the :
event that the resilient plastic element 14S disintegrates
as the result of a fire, the internal line pressure'will urge
the secondary sealing element 14D in contact w~th the ball 13
An additional feature of the construction and functions of
the secon~ary sealing arrangement i~ that.it is constructed
to be fully flexible to provide an angular degree of freedom
in addition to axial freedom which allows the primary seal
14S to fully contact the operative surfaces of the ball 13
under adverse assembly tolerances. The loading ring 17 is
designed for use in cryogenic environments to function as
a Belleville spring in order to maintain sufficient gasket
seating force at the sealing element 14S even during the
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l time intervals that there is a rapid change in temperature
from ambient to cryogenic temperatures. Although the
metallic materials in the valve possess approximately the
same thermal expansion coefficients, the various parts cool
down at different rates depending upon their mass and
proximity to the cryogenic fluid being controlled. Specifically,
it will be recognized that smaller elements will shrink more
quickly than the larger elements such as the valve body and
some seating force will be temporarily lost until all parts
stabilize at the lower temperatures.
It should be evident that the present invention has
disclosed an improved eccentric ball valve having primary I
and secondary sealing features that coact to provide effective ;
shutoff in high pressure applications as well as for cryogenic
ap ications,
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