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| United States Patent |
6,012,486
|
|
Rainwater
, et al.
|
January 11, 2000
|
Dual isolation valve with rectangular flow passageways
Abstract
A dual isolation valve comprises: a valve body with opposed inlet and
outlet ports that defines an inner cavity; a first valve member; and a
second valve member. The first valve member (preferably a plug) has a
narrower first end and a wider second end and is rotatably mounted within
the valve body cavity for rotation about a first axis of rotation
substantially perpendicular to the flow axis defined by the inlet and
outlet ports. The first valve member includes a substantially rectangular
flow passage. The first end of the first valve member extends away from
the second end along the first axis of rotation in a first direction, and
the first valve member is rotatable between an open position, in which the
flow passage is oriented to be generally aligned with and located on the
flow axis to enable fluid entering the inlet port to pass through the flow
passage, and a closed position, in which the flow passage is oriented to
be generally perpendicular to the flow axis to prevent fluid entering the
inlet port from passing through the flow passage. The second valve member
also has a narrower first end and a wider second end and is rotatably
mounted within the valve body cavity for rotation about a second axis of
rotation substantially perpendicular to the flow axis. The first end of
the second valve member extends away from the second end along the second
axis of rotation in a second direction opposite the first direction (such
that the first and second valve members are oriented in opposed
directions). The second valve member, which also has a substantially
rectangular flow passage, is rotatable between an open position, in which
the flow passage is oriented to be generally aligned with and located on
the flow axis to enable fluid exiting the first valve member to pass
through the flow passage to the outlet port, and a closed position, in
which the flow passage is oriented to be generally perpendicular to the
flow axis to prevent fluid exiting the first valve member from passing
through the flow passage to the outlet port. In this configuration, the
flow of fluid through valve can be disturbed less than with prior art dual
isolation valves while permitting extensive flow through the valve.
| Inventors:
|
Rainwater; Edward L. (Quitman, TX);
Spears; Ricky E. (Sulphur Springs, TX)
|
| Assignee:
|
Nordstrom Valves, Inc. (Sulphur Springs, TX)
|
| Appl. No.:
|
179622 |
| Filed:
|
October 27, 1998 |
| Intern'l Class: |
F16K 005/08 |
| Field of Search: |
137/613,614.21
|
References Cited
U.S. Patent Documents
| 2024905 | Dec., 1935 | Bard | 251/121.
|
| 2058747 | Oct., 1936 | Wilkins | 251/93.
|
| 3896857 | Jul., 1975 | Turner et al. | 137/628.
|
| 4275763 | Jun., 1981 | Fahrig | 137/613.
|
| 4276905 | Jul., 1981 | Lourdeaux | 137/613.
|
| 4498498 | Feb., 1985 | Martinez-Vera et al. | 137/613.
|
| 4529168 | Jul., 1985 | Timmermans | 251/210.
|
| 4846212 | Jul., 1989 | Scobie et al. | 137/240.
|
| 4884401 | Dec., 1989 | Metcalf et al. | 60/403.
|
| 5669415 | Sep., 1997 | Trunk | 137/613.
|
| 5685338 | Nov., 1997 | Trunk | 137/613.
|
| Foreign Patent Documents |
| 0 565 243 A1 | Oct., 1993 | EP | .
|
| 850297 | Oct., 1960 | GB.
| |
| 915446 | Jan., 1963 | GB.
| |
| 918020 | Feb., 1963 | GB.
| |
| 1 369 885 | Oct., 1974 | GB | .
|
| 2 300 693 | Nov., 1996 | GB | .
|
| 2 305 713 | Apr., 1997 | GB | .
|
| 2 305 713 | Nov., 1997 | GB | .
|
| WO 84/00795 | Mar., 1984 | WO | .
|
| WO 97/13085 | Apr., 1997 | WO | .
|
Other References
Specification for Pipeline Valves (Gate, Plug, Ball and Check Valves) API
Specification 6D (Spec 6D) Twenty-First Edition, Mar. 31, 1994.
Taper Plug Valves Pressure Balance Design; Christensens Valves (Brochure).
Lubricated Taper Plug Valves; Product Group; 9 Catalogue No. 184
(Brochure).
AZ Special Plug Valves With Flushing Device; AZ Armaturen (Brochure).
Nordstrom Steel Plug Valves; Nordstrom Valves, Inc. V-102-R2A (Brochures).
Super-H Pressure Balanced Plug Valve; Serck Audco Valves (Brochures).
Extracts from Advanced Products Catalogue Showing "C" Ring as a proprietary
item.
Double isolation valve wins on safety and savings; Valvetalk (Spring 1998).
|
Primary Examiner: Ferensic; Denise L.
Assistant Examiner: Kim; Joanne Y.
Attorney, Agent or Firm: Myers Bigel Sibley & Sajovec
Claims
What is claimed is:
1. A dual isolation valve, comprising:
a valve body with opposed inlet and outlet ports, said valve body defining
an inner cavity, and said inlet and outlet ports defining a flow axis
extending therebetween;
a first valve member having a narrower first end and a wider second end and
being rotatably mounted within said cavity for rotation about a first axis
of rotation substantially perpendicular to said flow axis, with said first
end extending away from said second end along said first axis of rotation
in a first direction, said first valve member having a substantially
rectangular flow passage, said first valve member being rotatable between
an open position, in which said flow passage is oriented to be generally
aligned with and located on said flow axis to enable fluid entering said
inlet port to pass through said flow passage, and a closed position, in
which said flow passage is oriented to be generally perpendicular to said
flow axis to prevent fluid entering said inlet port from passing through
said flow passage;
a second valve member having a narrower first end and a wider second end
and being rotatably mounted within said cavity for rotation about a second
axis of rotation substantially perpendicular to, said flow axis, with said
first end extending away from said second end along said second axis of
rotation in a second direction opposite said first direction, said second
valve member having a substantially rectangular flow passage, said second
valve member being rotatable between an open position, in which said flow
passage is oriented to be generally aligned with and located on said flow
axis to enable fluid exiting said first valve member to pass through said
flow passage to said outlet port, and a closed position, in which said
flow passage is oriented to be generally perpendicular to said flow axis
to prevent fluid exiting said first valve member from passing through said
flow passage to said outlet port.
2. The valve defined in claim 1, wherein said rectangular flow passage of
said first valve member is oriented such that the long axis of the
rectangle defined by said flow passage is substantially parallel with the
first axis of rotation, and wherein said rectangular flow passage of said
second valve member is oriented such that the long axis of the rectangle
defined by said flow passage is substantially parallel with the second
axis of rotation.
3. The valve defined in claim 1, wherein each of said rectangular passages
has a perimeter, said perimeters of said rectangular passages define a
length and a width, and a ratio of said length to said width is between
about 1.0 and 5.0.
4. The valve defined in claim 1, wherein said first and second valve
members are formed of one of iron, steel, ceramic or a composite material.
5. The valve defined in claim 1, wherein each of said first and second
valve members is frustoconical in shape.
6. A dual isolation valve, comprising:
a valve body with opposed inlet and outlet ports, said valve body defining
an inner cavity, and said inlet and outlet ports defining a flow axis
extending therebetween;
a first valve member having a narrower first end and a wider second end and
being rotatably mounted within said cavity for rotation about a first axis
of rotation substantially perpendicular to said flow axis, with said first
end extending away from said second end along said first axis of rotation
in a first direction, said first valve member having a substantially
rectangular flow passage, said first valve member being rotatable between
an open position, in which said flow passage is oriented to be generally
aligned with and located on said flow axis to enable fluid entering said
inlet port to pass through said flow passage, and a closed position, in
which said flow passage is oriented to be generally perpendicular to said
flow axis to prevent fluid entering said inlet port from passing through
said flow passage;
a second valve member having a narrower first end and a wider second end
and being rotatably mounted within said cavity for rotation about a second
axis of rotation substantially perpendicular to said flow axis, with said
first end extending away from said second end along said second axis of
rotation in a second direction opposite said first direction, said second
valve member having a substantially rectangular flow passage, said second
valve member being rotatable between an open position, in which said flow
passage is oriented to be generally aligned with and located on said flow
axis to enable fluid exiting said first valve member to pass through said
flow passage to said outlet port, and a closed position, in which said
flow passage is oriented to be generally perpendicular to said flow axis
to prevent fluid exiting said first valve member from passing through said
flow passage to said outlet port;
wherein each of said flow passages of said first and second valve members
defines a substantially rectangular perimeter, and wherein said
substantially rectangular perimeters are substantially aligned along said
flow axis.
7. The valve defined in claim 6, wherein said rectangular flow passage of
said first valve member is oriented such that the long axis of the
rectangle defined by said flow passage is substantially parallel with the
first axis of rotation, and wherein said rectangular flow passage of said
second valve member is oriented such that the long axis of the rectangle
defined by said flow passage is substantially parallel with the second
axis of rotation.
8. The valve defined in claim 6, wherein each of said perimeters of said
rectangular passages defines a length and a width, and a ratio of said
length to said width is between about 1.0 and 5.0.
9. The valve defined in claim 6, wherein said first and second valve
members are formed of one of iron, steel, ceramic, or a composite
material.
10. The valve defined in claim 6, wherein each of said first and second
valve members is frustoconical in shape.
Description
FIELD OF THE INVENTION
The present invention relates generally to valves, and relates more
specifically to dual-isolation valves.
BACKGROUND OF THE INVENTION
Valves are common components of almost any piping system. Although they can
be constructed in many different configurations and sizes, a typical valve
will include a few basic elements. These include: a valve body that houses
internal components within an internal cavity; inlet and outlet ports
leading to and from the valve body; one or more valve members positioned
within the cavity of the valve body with passageways for fluid flow; inlet
and outlet seats that seal the contact points between the inlet and outlet
ports and the valve member(s); and a valve stem or other structure or
mechanism that extends outside the cavity for turning the valve member(s)
within the valve body cavity. These components are attached such that
fluid entering the valve through the inlet pipe is either allowed to flow
through the valve member to the outlet pipe or prevented from such flow
based on the orientation of the valve member passageway relative to the
valve body.
One specialized valve configuration is the "dual isolation" valve
(sometimes also referred to as a "double block-and-bleed" valve), which
includes a pair of valve members positioned in series within the valve
cavity. Dual isolation valves are typically employed in piping systems in
which any leakage through the valve when closed would be extremely
detrimental, if not catastrophic. Exemplary uses include situations in
which (a) two very volatile materials are separated by the valve, (b) a
downstream operator is protected by the valve, (c) cross-contamination of
two materials is prevented by the valve, and (d) potable and nonpotable
water streams are separated by the valve.
An example of a dual isolation valve is illustrated in U.S. Pat. No.
5,669,415 to Trunk (the Trunk valve). The Trunk valve has two
frustoconical plugs, each of which is inverted (i.e., the narrower end of
the plug extends upwardly). Of course, the volumetric flow of the valve is
dependent on the size and shape of passageways in the plugs; however, the
size of the passageways is limited by the size of the plug itself, as
sufficient structure must surround the passageway to prevent the plug from
fracturing or collapsing during use. Typically, and as illustrated in
Trunk, valves having frustoconical plugs include trapezoidal flow
passageways in the plugs that match the trapezoidal cross-sectional shape
of the plugs in an effort to maximize the cross-sectional surface area of
the passageway.
Some dual isolation valves having two frustoconical plugs are configured
such that one plug is inverted as described above and the other is not
(i.e., the narrower end of the plug extends downwardly). This
configuration (exemplified in British Patent No. GB 2 305 713 B) is
employed in an attempt to reduce the cavity volume and overall length of
the valve; because the plugs are oriented 180 degrees apart about the flow
axis, they can be positioned closer together without interfering with one
another than is the case for identically oriented plugs.
Unfortunately, the reverse orientation of one plug within a dual isolation
valve can create reduction in volumetric flow when trapezoidal
cross-section flow passageways are employed. Because the perimeters of the
flow passageways are not aligned with each other (as can be the case for
dual isolation valves like the Trunk valve), a fluid flowing through the
valve is redirected somewhat from its flow path, thereby increasing the
turbulence in the flow and reducing flow efficiency. This shortcoming has
led to some valves having aligned circular flow passageways; however, such
passageways provide less cross-sectional area for flow and, thus, also
suffer from reduced volumetric flow.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to
provide a dual isolation valve with plugs that are oriented 180 degrees
apart from each other about the flow axis, but which do not suffer from
considerably reduced volumetric flow.
It is also an object of the present invention to provide such a valve with
high flow efficiency.
These and other objects are satisfied by the present invention, which is
directed to a dual isolation valve with improved flow characteristics. The
dual isolation valve comprises: a valve body with opposed inlet and outlet
ports that defines an inner cavity; a first valve member; and a second
valve member. The first valve member (preferably a frustoconical plug) has
a narrower first end and a wider second end and is rotatably mounted
within the valve body cavity for rotation about a first axis of rotation
substantially perpendicular to the flow axis defined by the inlet and
outlet ports. The first valve member includes a substantially rectangular
flow passage. The first end of the first valve member extends away from
the second end along the first axis of rotation in a first direction, and
the first valve member is rotatable between an open position, in which the
flow passage is oriented to be generally aligned with and located on the
flow axis to enable fluid entering the inlet port to pass through the flow
passage, and a closed position, in which the flow passage is oriented to
be generally perpendicular to the flow axis to prevent fluid entering the
inlet port from passing through the flow passage. The second valve member
also has a narrower first end and a wider second end and is rotatably
mounted within the valve body cavity for rotation about a second axis of
rotation substantially perpendicular to the flow axis. The first end of
the second valve member extends away from the second end along the second
axis of rotation in a second direction opposite the first direction (such
that the first and second valve members are oriented in opposed
directions). The second valve member, which also has a substantially
rectangular flow passage, is rotatable between an open position, in which
the flow passage is oriented to be generally aligned with and located on
the flow axis to enable fluid exiting the first valve member to pass
through the flow passage to the outlet port, and a closed position, in
which the flow passage is oriented to be generally perpendicular to the
flow axis to prevent fluid exiting the first valve member from passing
through the flow passage to the outlet port. In this configuration, the
flow of fluid through valve can be disturbed less than with prior art dual
isolation valves while permitting extensive flow through the valve.
In a preferred embodiment, the flow passageways are constructed such that
their perimeters are substantially aligned along the flow axis. In this
configuration, fluid flow is typically disturbed no more than for prior
art valves having circular passageways; however, the volume of flow can be
greater than for circular passageway valves because the rectangular shape
of the passageways permits greater flow volume.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a dual isolation valve of the present
invention.
FIG. 2 is a perspective cutaway view of the dual isolation valve of FIG. 1.
FIG. 3 is a section view through the inverted valve section of the dual
isolation valve of FIG. 1.
FIG. 4 is a section view through the both the upright and inverted valve
sections of the dual isolation valve of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention now will be described more fully hereinafter with
reference to the accompanying drawings, in which preferred embodiments of
the invention are shown. This invention may, however, be embodied in many
different forms and should not be construed as limited to the embodiments
set forth herein; rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the scope
of the invention to those skilled in the art.
Referring now to the drawings, a dual isolation valve, designated broadly
at 10, is illustrated in FIG. 1. The valve 10 includes a housing 12 having
an inlet port 14 at one end and an outlet port 40 at the opposite end. An
inlet flange 16 is fixed to the free end of the inlet port 14 to
facilitate attachment of the valve 10 within a piping system; similarly,
an outlet flange 42 is fixed to the free end of the outlet port 40.
Referring now to FIGS. 2 through 4, the housing 12 (shown in cross-section)
includes an inverted valve section 18 and an upright valve section 30
which house, respectively, an inverted plug 22 and an upright plug 34. The
inverted valve section 18 includes an internal surface 18a having an open
upper end. A cover assembly 19 covers the inverted valve section 18 and,
with the internal surface 18a, defines a cavity 20.
The plug 22 (typically formed of iron, steel, ceramic, plastic or a
composite material) has a frustoconical shape and is positioned within the
cavity 20 such that its narrower end 22a extends downwardly and its wider
end 22b extends upwardly. Typically, the plug 22 has a length to diameter
ratio of between about 1.0 and 5.0, and a taper of between 3 and 7
degrees, with about 4-5 degrees being preferred. The outer surface 23 of
the plug 22 contacts, nests within, and forms a seal with the internal
surface 18a of the inverted valve section 18. The seal between the plug 22
and the internal surface 18 is preferably augmented with a sealant, such
as a "Bingham-type" fluid, the composition of which is tailored to enhance
the sealing performance of the valve while ensuring compatibility with the
line media.
The plug 22 includes a substantially rectangular passageway 24, which
enables fluid to pass from the inlet port 14 to the upright valve section
30 along a flow axis F. Preferably, the passageway 24 has a length (i.e.,
long axis) to width (i.e., short axis) ratio of between about 1.0 and 5.0.
A stem 26 is fixed to the narrow end of the plug 22 and extends through an
aperture in the inverted valve section 18 to provide access to an operator
to rotate the plug 22. Illustratively, the stem 26 is square in
cross-section to mate with a similarly shaped wrench; however, other
configurations for the stem 26 (such as hexagonal) may be employed, as may
more complex valve member rotation mechanisms, such as that described in
British Patent GB2305713B. At its wider end, the plug 22 includes a
adjusting screw 28 that extends into and mates with a round recess 19a in
the cap 19.
Referring again to FIGS. 2 through 4, the internal surface 30a of the
upright valve section 30, along with a cover assembly 31 attached to its
lower portion, define a cavity 32. Within the cavity 32, a frustoconical
plug 34 is rotatably mounted and seated in similar fashion to the plug 22,
with the outer surface 35 of the plug 34 contacting the internal surface
30a. The plug 34 is oriented such that it is oriented about the flow axis
F 180.degree. from the plug 22; i.e., its narrower end 34a extends
upwardly and its lower end 34b extends downwardly. The preferred
dimensions set forth above for the plug 22 are equally applicable for the
plug 30.
The plug 34 includes a rectangular passageway 36. Illustratively and
preferably, the passageway 36 should be sized to be substantially the same
in cross-section as the passageway 24, and its perimeter should be
substantially aligned with the perimeter of the passageway 24 relative to
the flow axis F. Like the plug 22, the plug 34 also includes a stem 38
that extends through an aperture in the upright valve section 30 to enable
operator access for rotating the plug 34, and further includes a adjusting
screw 39 at its wider end 34a that extends into and mates with a recess
31a in the cap 31.
In operation, the valve 10 takes a closed position (i.e., one in which
fluid is prevented from flowing from the inlet port 14 to the outlet port
40) by rotating the plugs 22,34 to their closed positions. This is
performed by using a wrench or other tool to rotate the stems 26,38
counterclockwise. Such rotation causes each plug to be oriented about its
axis of rotation so that its respective passageway 24, 36 is substantially
perpendicular to the flow axis F. In this position, the outer surfaces 23,
35 of the plugs 22, 34 contact the internal surfaces 18a, 30a, thereby
sealing the inlet and outlet ports 14, 40 from each other.
In the closed position, the valve 10 has two plugs positioned to prevent
fluid flow from the inlet port 14 to the outlet port 40. Thus, if some
degree of leakage occurs through the seal between the plug 22 and the
internal surface 18a (such as by erosion or misalignment of the plug 22,
or by inadvertent opening of the plug 22), the interaction between the
plug 34 and the internal surface 30a provides a back-up seal that can
prevent fluid flow to the outlet port 40.
The valve 10 can be opened by rotating each valve stem 26, 38 clockwise
one-quarter turn (90 degrees) around its axis of rotation. Such rotation
drives each plug 22, 34 to a position in which its respective passageway
24, 36 is oriented to be substantially parallel to the flow axis F. As
such, fluid is then free to flow from the inlet port 14 through the
passageways 24, 36 and into the outlet port 40.
As shown in FIGS. 3 and 4, rotation of the plugs 22, 34 to their open
positions causes the passageways 24, 36 to be positioned such that their
perimeters are substantially aligned along the flow axis F. As a result,
fluid flowing through the passageways 24, 36 is not substantially diverted
from its flow path in order to pass therethrough. Accordingly, the
volumetric flow rate of the valve 10 is not reduced due to the creation of
turbulence caused by the misalignment of plug passageways that occurs in
other "reverse orientation" dual isolation plug valves.
In addition, the rectangular shape of the passageways 24, 36 increases the
cross-sectional area available for flow. As such, the volumetric flow rate
of the valve 10 is greater than would be the case for a circular
passageway having a diameter equal to the length or width of a rectangular
passageway such as that illustrated and described herein. Of course, the
plugs 22, 34 may be operated independently of one another, so that the
valve 10 may be used as a single plug valve with a redundant plug.
The foregoing is illustrative of the present invention and is not to be
construed as limiting thereof. Although exemplary embodiments of this
invention have been described, those skilled in the art will readily
appreciate that many modifications are possible in the exemplary
embodiments without materially departing from the novel teachings and
advantages of this invention. Accordingly, all such modifications are
intended to be included within the scope of this invention as defined in
the claims. The invention is defined by the following claims, with
equivalents of the claims to be included therein. In the claims,
means-plus-function clauses are intended to cover the structures described
herein as performing the recited function and not only structural
equivalents but also equivalent structures.
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