Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
SEAI, ~SSEMBLY
BACKGROUND AND SUMMARY OF T~E INVENTION
This invention relates to bi-directional valves, and
~in particular to a new sealing means construction having
applications in butterfly valves. Butterfly valves have many
advantages over other types of valves in fluid flow regulation,
mo~t notable being ].ower cost to the manufacturer, quickness o~
opening and low restriction to fluid flow when fully open.
Howeverl these valves generally have been limited to low
pressure applications because of their inability to seal
tightly at high pressures. In some prior art valves, the seal~,
are located in grooves in the valve body which often become
:: :
dislodge&~when the~valve is open thereby permittiny fluid to
flow~around the seal. ~In other prior art valves, high pressure
fluid~may leak through the vaLve by flowing ~etween the valve
body and seal; uhile in many other prior art valves~ contact
between~the~disc and~seal must be made~so tight in order to
prevent leakage that opening the valve, particularly large
diameter valves, requires a large torque. Furthermore, in
several prior art valves used in high pressure and/or high
temperature applications, the seat ring or sealing means lo,es
the desired preloading on the seat ring sealing face as the
se~at ring expancls~. In still other ~loating seal valves, high
pressure fluid, which enters the recess when the valve is
closed, cannot escape when the valve is opened, thus causing
the seal to blow out
~ : .
In other floating seat valves, an attempt is made
to reduce the torque required to open and close the disc,
while improving the retention o the seat ring sealing face
as the seat ring expands by employing indirect or partial
application of resilient means and fluid pressure forces on
the sealing face.
It is an object of the present invention to provide
an improved bi-directional valve which will neither leak nor
blow out under high pressures and which is operable with a
relatively low torque.
A further object of this invention is to provide a
reliable, exceptional long life, relatively inexpensive and
easily rep]aceable and serviceable valve seat.
It is still a further object of this inventlon to
provide a bi~directional valve having improved sealing means
which ~ully utilizes direct application of resilient means and
fluid pressure forces on the sealing face.
The bi-directional valve herein comprises a valve
body having a flow passage therethrough with a recess in
proximity to the passage, the recess having a planar surface
with a groove therein. A retaining ring surrounds the passage
and is detachably affixed to the valve body. The ring has a
recess therein, the recess having a surface with a groove therein.
A chamber, open to the passage, is formed between the recesses.
The chamber has an axial centerline parallel to the planar
surface. A closure means is pivotally positioned in the
passage between an open and a closed position to allow or
prevent, respectively, fluid flow therethrough. The closure
means has a peripheral land adapted to engage a sealing means.
The sealing means includes an outer portion adapted to be
secured between the valve body and the retaining ring; an
offset hinged L-shaped portion integral with the outer portion,
~ -2-
~ ~3
the L-shaped portion having a cavity therein adapted to
recei~e a resilient back-up means; a substantially rectangular
inner portion integral with the L-shaped portion, the inner
portion having a shoulder ring portion on each side thereoE,
with the shoulder ring portion on one side projecting into
the groove of the valve body and the shoulder ring portion on
the other side projecting into the groove of the retaining ring;
and a resilient back-up means positioned in the cavity. When
the sealing means is pressurized by fluid from either side
thereof upon closing of the closure means, the parallel
relationship of the planar surface and the axial centerline
causes the back-up means and fluid directed on the inner portion -
to apply their combined forces substantially perpendicular to
the peripheral land to effect sealing of the valve.
Fig. 1 is a plan view, in section, of a butter~ly
valve utilizing the seal of this invention with the closure
means shown in solid lines in the closed position~ and in
broken lines in the open position.
Fig. 2 is an enlargement of the seal of Fig. 1 with
the seal unloaded. Such a condition would occur when the
valve is open permitting flu1d flow through the valve.
Fig. 3 is an enlargement of the seal of Fig. 1 with
the seal in a preloaded condition. Such a condition would
occur when the closure means is closed and no line pressure is
applied.
Fig. 4 is an enlargement o~ the seal of Fig. 1 with
the seal in a preloaded and pressurized condition. Such a
condition would occur when the closure means is closed and
pressure differential across the valve forces line fluid into
-3-
,~
~. , . : . , ,, .. ~ . . . . . .
the channel on one side of the sealing means.
Fig. 5 is an enlargemen~ of the seal of Fig. 1 with
the seal in a preloaded and pressurized condition. Such a
condition would occur when the closure means is closed and
pressure difEerential across the valve Eorces line fluid into
the channel on the other side of the sealing means.
:
Referring to the drawings and more particularly to
;Figure 1, a valve, generally represented by re~erence numeral
10, having a flow passage 12 in valve body 14 is shown located
in conduit 18. Valve 10 may be secured in the conduit by
welding, bolted flanges, or other common way. A valve closure
:
means, such as valve disc 21 having curvilinear peripheral land
,
22 is shown in solid lines in the closed position and in broken
lines in the open pGsition. Disc 21 is secured to stem 16
which protrudes through valve body 14 and has a handle or other
means (not shown) attached thereto in the usual manner to
provide an axis about which disc 21 may be rotated to open or
close the flow passage 12. Sealing means 30 includes seat ring
31 and resilient back-up means, such as spring 50, and is
disposed between valve body 14 and retaining ring 40 which is
detachably connected to valve body 14 via fastene~ 42, as
shown. Since the axis of rotation of disc 21 does not coincide
with a centerline through seat ring 31, there is eccentric
movement of the disc relative ~to the seat ring causing a faster
break-away between disc 21 and seat ring 31 than would
otherwise result if the disc and seat ring centerlines
~ A -
coincided. ~owever, the subjecl invention may be practiced
with coincidence of the disc ax:is of rotation and the seat rincJ
centerline.
Referring to Figure 2, valve body 14 has a recess
therein formed by planar suraces 72 and 72A which are
separated by first groove 76 therebetween, and second groove 78
which is adjacent surEace 72n Retaining ring 40 has a recess
therein comprising surfaces 82 and ~2A disposed in
juxtaposition to surfaces 72 and 72A, respectively, and
separated by groove 36 therebetween, first surface 88
continuvus of surface 82 in a plane normal thereto, and
conf.ining surface 89 continuous of surface 38 in a plane
substantially normal thereto.
The aforementioned recesses of valve body 14 and
retaining ring 40 de:Eine chamber 60 which is adapted to receive
sealing means 30. It should be noted that chamber 60 is so
disposed that its axial centerline is positioned parallel to
planar surface 72 of valve body 14.
: :Sealing means 3~is comprised of seat ring 31, made of
heat and chemically resistant material such as fluorocarbon,
urethane or elastomeric polymers/ and resilient back-up means,
such as a metallic garter-type spring 50. Seat ring 31
includes in~egrally connected outer portion 32, hinged L-shaped
portion 33, and inner portion 34. When the disc is in open
position and wlth retaining ring 40 secured tv valve body 14,
outer portion 32 is sized, preferably, so as to be fixedly
reta:ined in place in an area defined by second groove 78 and
confining surEace 39. The volume of mass oE outer portion 32
is sized larger than the~volume of material that can be
.
- 5 -
contained between second yroove 78 and confining surfacc ~9, so
that, the outer port:ion becomes compressed theLein Eorming a
fluid leak-tight seal around its periphery. To assure fi~:ed
retention oE the outer portion therein, the area is,
preferably, configurated to have narrowes~ extent along line
AA' formed by joining the points of contact of surface 88 to
confining surface 89 and of planar surface 72 to second yroove
78. ~hough this embodiment is preferred, outer portion 3~ can
be of any suitable configuration and retained ~y any suitat~le
means.
;~ ~ Por-~ion 33r integrally joined to outer portion 32,
contains cavity 55 therein, which i5 adapted to receive spring
50:which exerts counter or supportive forces to structure in
contact thereto, to prevent the collapse of portion 33 when
pressure diferential i.s exerted on the retaining ring sicle o~
seat ring 31. Portion 33 is freely suspended from portion 32
in chamber 60, so that, pressure differential being exertecl on
: either side of se t riny 31 causes hinge-like movement of
portions 33 and 34 about line AA'. Portion 33 has surface '31
the.reon, which is, preferably, of cut hack or chamfered
configuration thereby permitt.ing a greater unoccupied portion
of chamber 60, thus assuring unimpeded hinge-like movement of
: portions 33 anrl 34 ahout line ~A'~ Portion 33, though
resilient and flexible, is of non-conical L-shaped
confiyuration which upon loadin~ via fluid pressure assumes a
radii arc shape.
Inner porti.on 34 r :integral to portion 33l is
substantially of rectangular shape, in section, h~ving sealillg
surface 36. Inner portion 34 has integral shoulder ring
'
~4~
portions 35 and 37 which project into grooves 86 t 76,
respectively, for controlling the amount of projection of eat
ring 31 into passage 12, and preventing blow out of seat r.in(3
31 when disc 21 is opened or closed. Sealing surface 36 may be
spherical, conical o~ other similar shape, and portions 35 and
37 are, preferably, of trapezoi.~al configuration, in section.
Since chamber 60 is wider than 2ortions 33 and 34, channels
100, 101 are provided between portions 33, 34 and the recesses
of ring 40 and valve body 14/ respectively, facilitating
insertion of seat ring 31 into chamber 60, pressurization and
depressurization of cavity 55 and freedom of movement of
portions 33 and 34 during valve operation.
~ eferring to Figure 3, in its closed, unpressuri~ed
condition, disc 21 ~edges land 22 into sealing surface 36
causing It to expand o~utwardly creating interference load ].10.
Channels lOO and 101 are approximatel~ of equal width.
In Figure 4, fluId under pressure is directed into
channel lQ0. Fluid pressure component:l20 acts normally on
portions~33 and 34 causiIlg theIr pivotal movement about line
AA'. Spring 50, while acting t.o prevent the collapse of
portion 33, moves with portion 33 until fully compressed
against planar surface 72. The movement of portions 33 and 34
results in radial enlargemerIt of channel 100, and abutting
engagement of inner portion 34 ~and shoulder ring portion .37
with surface 72A and groove 76, respectively, preventing
further displacement of inner portion 34.
Fluid pressure component 122 acts radially on portion
:33 forcing .it and spring(50 downward, transmitting through
, ~
: ~ inner:portion 34 d.irectly onto sealing surface 360 Due to the
parallel:reIationshIp o pla~ar surface 72 and centerline LC of
7 -
chamber ~0, full fluid pressure compont~llt 122 and undef:lect~]
spring force component 51 is exerted dir~ctly onto surEace ::3G.
An improved dynamic loading of sealing surface 36 is provi.ded
by the direct applications of these forces and interference
load 110 thereon resulting in substantially perpendicular
application of these forces onto land 22.
In Figure 5, fluid under pressure is directed into
channel 101. Fluid pressure component 130 acts normally on
inner portion 34/ and cavity 55 of portion 33 causing pivotal.
movement of portlons 33 and 34 about line AA', radial
enlargement of channel 101, and engagement of surface 91 w.i~:h
the recess of ring 40. Inner portion 34 and shoulder ring
portion 35 are in abutting enga~ement with surEace ~2A al~d
groove 86, respectfully.
Fluid pressure component 130 can be broken down for
purposes of explanation, into partial force components 56, ';7
and 58. Surfaces ~2, 88 act as constraints for portion 33
under the loads of part.ial force componellts 56, S8,
respectfully. Partia:l force component 57, as well as
undefIect.ed spring force component 51, is transmitted through
inner portion 34 directly onto surface 3~, providing by their
direct applications and interference load 110, an improved
dynamic loading of surface 36 resulting in substantially
perpendicular application of these Eorces onto land 22.
Although a certain embodiment has been described and
illustrated,.modificcltion may be made herein, as by adding,
combining or subdividing parts or by substituting equivalents
or by applying the invention to other types of valves or
mechanisms while retaining advantages and ben~fi~s of the
invention, which itself is define~ in the followirlg claims.
