Double Shut-Off Valve

Abstract

The double shutoff valve includes a valve body defining an internal cavity and a flow tube extending therethrough, an outer cylinder including a body portion defining the internal cavity and a throughbore extending therethrough, the outer cylinder being rotatably disposed within the internal cavity of the valve body, and an inner cylinder including a body portion defining a throughbore extending therethrough, the inner cylinder being rotatably disposed within the internal cavity of the outer cylinder, the inner cylinder including a body portion defining a throughbore extending therethrough, both the inner and outer cylinders being rotatable between a first position in which the throughbore of the outer and inner cylinders is aligned with the flow tube and a second position in which the throughbore of the outer and inner cylinders is transverse to the flow tube.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Application No. 63 / 034,630, filed June 4, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates generally to double shutoff valves for controlling fluid flow within a nuclear reactor, and more particularly to a shutoff valve that provides double shutoff functionality in a compact design. [Background technology]

[0003] Each primary coolant line entering and exiting the reactor pressure vessel 11 and exiting the containment building 12 within which the reactor 10 is located must contain two independently operable shutoff or isolation valves, which can operate in series. The rationale for redundancy is based on the possibility of a coolant line break or loss-of-coolant accident (LOCA). If a coolant line breaks and one shutoff valve fails, the remaining shutoff valve can still be used to ensure the flow of primary coolant through the coolant line. Figure 1 shows a typical nuclear reactor 10 within a containment building 12. As shown, the supply coolant line 14 contains two independent check valves 16 in series. The coolant outlet line 18 contains two manually / electromechanically operated shutoff valves 20 in series. Similarly, redundant shutoff valves may also be used in other non-nuclear power plants or ships where failure of just one valve could lead to a catastrophic accident.

[0004] FIG. 2 is a cutaway view of a typical shutoff valve 22. Prior art shutoff valves 22 consist of four main components: a stem 24, a body 26, a rotating ball or cylinder 28, and a seal seat or O-ring 30. As is known, with a typical shutoff valve 22, the stem 24 rotates the ball / cylinder 28 a quarter turn (90°) to transition between an open flow path (as shown) and a closed flow path. The ball / cylinder 28 includes a through-hole 32, and when the through-hole 32 is aligned with the flow tube 34 in the body 26, fluid or gas can pass from a first side to a second side of the shutoff valve 22. When the ball / cylinder 28 is rotated 90° from the position shown in FIG. 2, the through-hole 32 in the ball / cylinder 28 is no longer aligned with the flow tube 34, thereby preventing fluid or gas from passing through the shutoff valve 22. To achieve a redundant system, two shutoff valves 22a, 22b are aligned in series. Typically, two isolation valves 22a, 22b are bolted together end-to-end, as shown in Figure 3. Due to the size of the individual isolation valves 22a, 22b, the length of the two valves in series can be quite long. Therefore, utilizing two standard isolation valves 22a, 22b in series can be problematic where space is limited, such as, but not limited to, in nuclear reactor containment vessels such as those used on naval vessels.

[0005] In an alternative redundant configuration, shown in FIG. 4, a dual shutoff ball / cylinder valve 22c includes two ball / cylinders 28 located within the same valve body 26. While this reduces the overall length of the valve, as opposed to two separate shutoff valves 22a, 22b bolted together (FIG. 2), the large valve actuator 36 limits the ability to reduce the overall length of the valve when the valve actuators 36 are located on the same side of the valve body 26. One solution to help reduce the overall length of the shutoff valve 22c is to position the actuators at 90° or 180° to each other, as shown in FIG. 5. While this configuration of the actuators 36 can reduce the overall length of the shutoff valve 22c, the width must still be at least as wide as the width of the two ball / cylinders along the potential flow direction.

[0006] Therefore, there is at least a need for a system and method for controlling the flow of primary coolant through coolant lines passing through the containment vessel of a nuclear reactor. Summary of the Invention

[0007] One embodiment of a double shutoff valve according to the present invention includes a valve body defining an internal cavity and a flow tube therethrough, an outer cylinder including a body portion defining the internal cavity and a throughbore therethrough, the outer cylinder rotatably disposed within the internal cavity of the valve body, and an inner cylinder including a body portion defining a throughbore through the inner cylinder, the inner cylinder rotatably disposed within the internal cavity of the outer cylinder, both of which are rotatable between a first position in which the throughbore of the outer cylinder and the inner cylinder is aligned with the flow tube and a second position in which the throughbore of the outer cylinder and the inner cylinder is transverse to the flow tube.

[0008] One embodiment of a nuclear reactor according to the present invention provides a nuclear reactor disposed within a containment structure, the containment structure having a reactor core disposed within a pressure vessel, a primary coolant inlet line passing through both the pressure vessel and the containment structure, and a first double isolation valve disposed within the containment structure and in fluid communication with the primary coolant inlet line, the first double isolation valve including: a valve body defining an internal cavity and a flow tube extending therethrough; an outer cylinder including a body portion defining the internal cavity and a throughbore extending therethrough, the outer cylinder rotatably disposed within the internal cavity of the valve body; and an inner cylinder including a body portion defining a throughbore extending therethrough, the inner cylinder rotatably disposed within the internal cavity of the outer cylinder, the inner cylinder including a body portion defining a throughbore extending therethrough, both of the inner and outer cylinders rotatable between a first position in which a central longitudinal axis of the throughbore of the outer cylinder and a central longitudinal axis of the inner cylinder are aligned with a central longitudinal axis of the flow tube, and a second position in which the central longitudinal axes of the throughbore of the outer and inner cylinders are not aligned with the central longitudinal axis of the flow tube.

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiment(s) of the invention and, together with the description, serve to explain the principles of the invention.

[0010] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, this invention may 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 satisfy applicable legal requirements. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a double isolation valve in a prior art nuclear reactor. [Figure 2] FIG. 1 is a partial cross-sectional view of a prior art ball-type shut-off valve. [Figure 3] FIG. 1 is a perspective view of two prior art shut-off valves in series to provide redundant shut-off functionality. [Figure 4] FIG. 1 is a perspective view of two ball-type shut-off valves with rotating balls in series and their valve actuators located on the same side of the assembly. [Figure 5] FIG. 1 is a perspective cutaway view of two ball-type valves with rotating balls in series and their valve actuators located on opposite (i.e., sides) of the assembly. [Figure 6] 1 is a perspective view of a double shutoff valve according to one embodiment of the present invention; FIG. [Figure 7A] FIG. 7 is a cross-sectional view of the double shutoff valve shown in FIG. 6. [Figure 7B] FIG. 7 is an exploded cross-sectional view of the double shutoff valve shown in FIG. 6. [Figure 8A] 8 is a partial cross-sectional view showing the operating position of the double shutoff valve shown in FIG. 7. [Figure 8B] 8 is a partial cross-sectional view showing the operating position of the double shutoff valve shown in FIG. 7. [Figure 8C] 8 is a partial cross-sectional view showing the operating position of the double shutoff valve shown in FIG. 7. [Figure 8D]8 is a partial cross-sectional view showing the operating position of the double shutoff valve shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0012] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention according to the present disclosure.

[0013] Reference will now be made to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, not limitation of the invention. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0014] As used herein, terms referring to directions or positions relative to the orientation of a double shutoff valve, such as, but not limited to, "vertical," "horizontal," "top," "bottom," "above," or "below," refer to directions and relative positions relative to the operation of the double shutoff valve, as shown in Figures 8A-8D. Thus, for example, the terms "vertical" and "top" refer to a vertical orientation and relative upward position in the perspective views of Figures 8A-8D, and should be understood in that context even with respect to double shutoff valves that may be oriented in different directions.

[0015] Furthermore, the term "or" as used in this application and the appended claims is intended to mean an inclusive "or" rather than an exclusive "or." That is, unless otherwise specified or clear from the context, the phrase "X uses A or B" is intended to mean any of the natural inclusive permutations. That is, the phrase "X uses A or B" is satisfied by any of the instances where X uses A, X uses B, or X uses both A and B. Furthermore, the articles "a" and "an" as used in this application and the appended claims should generally be interpreted to mean "one or more" unless otherwise specified or clear from the context that the singular form is intended. Throughout this specification and the claims, the following terms shall take at least the meaning expressly associated therewith, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms but merely provide illustrative examples of the terms. The meanings of "a," "an," and "the" may include plural references, and the meaning of "in" may include "in" and "on." The phrase "in one embodiment" as used herein does not necessarily refer to the same embodiment, although it may.

[0016] Referring now to the drawings, a double shutoff valve 40 according to one embodiment of the present invention is shown in Figures 6, 7A, and 7B. As shown, the double shutoff valve 40 includes a valve body 42 defining an internal cavity 44 and a flow tube 46 in fluid communication with the internal cavity 44. One or more flanges 48 are provided for connecting the double shutoff valve 40 to associated piping (not shown). An outer ball or cylinder 50 is rotatably disposed within the internal cavity 44 of the valve body 42 and defines an internal cavity 58 and a throughbore 60 in fluid communication therewith. As will be described in more detail below, the outer surface of the outer cylinder 50 is shaped to correspond to the inner surface of the valve body 42 that defines the internal cavity 44 of the valve body 42.

[0017] As described above, the outer cylinder 50 is rotatable within the valve body 42 such that the throughbore 60 of the outer cylinder 50 is aligned with the flow conduit 46 of the valve body 42. Similarly, the inner ball or cylinder 80 is rotatably disposed within the interior cavity 58 of the outer cylinder 50 and defines a throughbore 88 therethrough. The outer surface of the inner cylinder 80 is shaped to correspond to the inner surface of the interior cavity 58 of the outer cylinder 50, such that the inner cylinder 80 is rotatable relative to the outer cylinder 50. Thus, the throughbore 88 of the inner cylinder 80 is aligned with the throughbore 60 of the outer cylinder 50, thereby aligning with the flow conduit 46 of the valve body 42 and thereby providing a flow path through the double shutoff valve 40.

[0018] As best seen in FIG. 7B , the outer cylinder 50 includes a generally cylindrical body portion 52 including a dome-shaped outer surface portion 56 at its distal end, and a cylindrical outer surface portion 54 extending from its proximal end to the dome-shaped outer surface portion 56. Still referring to FIG. 8A , a pair of annular grooves 62 are formed in the cylindrical outer surface portion 54 of the body portion 52 above and below the throughbore 60. A pair of O-rings 64 are received in the annular grooves 62 such that a watertight or airtight seal is formed between the O-rings 64 and the cylindrical sidewall 45 of the internal cavity 44 of the valve body 42, both above and below the throughbore 60. A bonnet 66 is disposed at the proximal end of the body portion 52 of the outer cylinder 50, and an actuator stem 68 extends therethrough and is attached to the proximal end of the body portion 52 of the outer cylinder 50. The actuator stem 68 can be used to rotate the outer cylinder 50 from a first position, as shown in FIG. 8A , in which the through-hole 60 is aligned with the flow conduit 46 of the valve body 42, to a second position in which the through-hole 60 of the outer cylinder 50 is not aligned with the flow conduit 46 of the valve body 42, thereby preventing fluid flow through the double shutoff valve 40. Referring again to FIG. 7B , the outer cylinder 50 defines an internal cavity 58 therein. As best seen in FIG. 7B , the internal cavity 58 extends from the distal end of the body portion, or dome-shaped outer surface portion 56, toward the proximal end of the body portion 52 and includes a generally cylindrical sidewall portion 70 and a dome-shaped bottom wall 57. Additionally, a trunnion recess 72 is formed along the central longitudinal axis of both the outer cylinder 50 and the inner cylinder 80.

[0019] 7B, inner cylinder 80 includes a body portion 82 having a generally cylindrical outer surface portion 84 and a dome-shaped outer surface portion 86 at its distal end. Cylindrical outer surface portion 84 and dome-shaped outer surface portion 86 of inner cylinder 80 are shaped to correspond to cylindrical side wall 55 and dome-shaped bottom wall 57 of interior cavity 58 defined by outer cylinder 50. Thus, inner cylinder 80 is rotatable relative to both outer cylinder 50 and valve body 42 of double shutoff valve 40.

[0020] 8C , a pair of annular grooves 90 are formed in the cylindrical outer surface portion 84 of the body portion 82 above and below the through-hole 88. A pair of O-rings 92 are received in the annular grooves 90 such that a watertight or airtight seal is formed between the O-rings 92 and the cylindrical sidewall 55 of the interior cavity 58 of the outer cylinder 50, both above and below the through-hole 88. A bonnet 94 is disposed at the proximal end of the body portion 82 of the inner cylinder 80, and an actuator stem 96 extends therethrough and is attached to the proximal end of the body portion 82 of the inner cylinder 80. The actuator stem 96 can be used to rotate the inner cylinder 80 from a first position, as shown in FIG. 8C , in which the through-hole 88 is aligned with both the through-hole 60 of the outer cylinder 50 and the flow conduit 46 of the valve body 42, to a second position in which the through-hole 88 of the inner cylinder 80 is not aligned with either the through-hole of the outer cylinder 50 or the flow conduit 46 of the valve body 42, thereby preventing fluid from flowing through the double shutoff valve 40. To provide the double shutoff function, the outer cylinder 50 is rotated to the position shown in FIG. 8B and the inner cylinder 80 is rotated to the position shown in FIG. 8D . Thus, the through-hole 60 of the outer cylinder and the through-hole 88 of the inner cylinder 80 are aligned, but neither the through-hole 60 nor the through-hole 88 is aligned with the flow conduit 46 of the double shutoff valve 40. A trunnion protrusion 98 extends outward from the dome-shaped outer surface portion 86 of the inner cylinder 80 and is received in the trunnion recess 72 to ensure proper alignment of the outer cylinder 50 and inner cylinder 80 during rotation relative to one another.

[0021] Although one or more preferred embodiments of the present invention have been described above, it should be understood that those skilled in the art can make various modifications and variations therein without departing from the scope and spirit of the invention. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.

Claims

1. A double shut-off valve, a valve body defining an internal cavity and a flow tube extending therethrough; an outer cylinder including a body portion defining an internal cavity and a throughbore extending therethrough, the outer cylinder being rotatably disposed within the internal cavity of the valve body; an inner cylinder including a body portion defining a throughbore therethrough, the inner cylinder being rotatably disposed within the interior cavity of the outer cylinder; and both the inner cylinder and the outer cylinder are rotatable between a first position in which the central longitudinal axis of the through-hole of the outer cylinder and the central longitudinal axis of the inner cylinder are aligned with the central longitudinal axis of the flow tube, and a second position in which the central longitudinal axes of the through-holes of the outer cylinder and the inner cylinder are not aligned with the central longitudinal axis of the flow tube; and A double shutoff valve, wherein the inner cylinder is rotatable relative to the valve body independently of the outer cylinder.

2. A double shutoff valve, a valve body defining an internal cavity and a flow tube extending therethrough; an outer cylinder including a body portion defining an internal cavity and a throughbore extending therethrough, the outer cylinder being rotatably disposed within the internal cavity of the valve body; an inner cylinder including a body portion defining a throughbore therethrough, the inner cylinder being rotatably disposed within the interior cavity of the outer cylinder; and both the inner cylinder and the outer cylinder are rotatable between a first position in which the central longitudinal axis of the through-hole of the outer cylinder and the central longitudinal axis of the inner cylinder are aligned with the central longitudinal axis of the flow tube, and a second position in which the central longitudinal axes of the through-holes of the outer cylinder and the inner cylinder are not aligned with the central longitudinal axis of the flow tube; and The double shutoff valve further includes an inner cylinder valve actuator and an outer cylinder valve actuator, the valve actuators extending outwardly from opposite sides of the valve body.

3. 2. The double shutoff valve of claim 1, further comprising a pair of annular grooves defined in the cylindrical outer surface of the body portion of the outer cylinder, the annular grooves being parallel to each other and disposed on either side of the through hole in the outer cylinder.

4. 4. The double shutoff valve of claim 3, further comprising a pair of O-rings, each O-ring disposed in a corresponding one of the annular grooves of the outer cylinder.

5. 2. The double shutoff valve of claim 1, wherein the central longitudinal axis of said outer cylinder is aligned with the central longitudinal axis of said inner cylinder.

6. 1. A nuclear reactor disposed within a containment structure, a reactor core disposed within a pressure vessel; a primary coolant inlet line passing through both the pressure vessel and the containment structure; a first double isolation valve disposed within the containment structure and in fluid communication with the primary coolant inlet line; and the first double shutoff valve comprises: a valve body defining an internal cavity and a flow tube extending therethrough; an outer cylinder including a body portion defining an internal cavity and a throughbore extending therethrough, the outer cylinder being rotatably disposed within the internal cavity of the valve body; an inner cylinder including a body portion defining a throughbore therethrough, the inner cylinder being rotatably disposed within the interior cavity of the outer cylinder; and both the inner cylinder and the outer cylinder are rotatable between a first position in which the central longitudinal axis of the through-hole of the outer cylinder and the central longitudinal axis of the inner cylinder are aligned with the central longitudinal axis of the flow tube, and a second position in which the central longitudinal axes of the through-holes of the outer cylinder and the inner cylinder are not aligned with the central longitudinal axis of the flow tube; and The reactor, wherein the inner cylinder of the first double isolation valve is rotatable relative to the valve body independently of the outer cylinder.

7. 7. The nuclear reactor of claim 6, wherein the first isolation valve further comprises an inner cylinder valve actuator and an outer cylinder valve actuator, the valve actuators extending outwardly from opposite sides of the valve body.

8. 7. The nuclear reactor of claim 6, wherein the first shut-off valve further comprises a pair of annular grooves defined in a cylindrical outer surface of the body portion of the outer cylinder, the annular grooves being parallel to each other and disposed on opposite sides of the through hole in the outer cylinder.

9. 9. The nuclear reactor of claim 8, wherein the first isolation valve further comprises a pair of O-rings, each O-ring disposed in a corresponding one of the annular grooves of the outer cylinder.

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