US-12624771-B2 - Stop valve for installation in a pipeline, in particular in a pipeline of a nuclear facility

US12624771B2US 12624771 B2US12624771 B2US 12624771B2US-12624771-B2

Abstract

A stop valve for installation in a pipeline is utilized to stop a fluid flow through the pipeline in the event of an operational failure. The valve includes a valve housing including a flow channel therethrough, and a closure member arranged at least partially in the flow channel and reversibly transferrable between an open position and a closed position. The valve further includes a non-electrically driven actuator mechanism operatively coupled to the closure member for transferring the closure member at least from the open position to the closed position. The actuator mechanism is configured to be activated by a fluid flow through the flow channel. The valve includes at least one position indicator to indicate whether the closure member is in the open position or in the closed position. The position indicator includes at least one indicator member movably magnetically coupled to the closure member.

Inventors

Leo Ornot

Assignees

KERNKRAFTWERK GÖSGEN-DÄNIKEN AG

Dates

Publication Date: 20260512
Application Date: 20201208
Priority Date: 20191209

Claims (16)

1 . A stop valve for installation in a pipeline to stop a fluid flow through the pipeline in the event of an operational failure, the stop valve comprising: a valve housing including a flow channel passing through the valve housing, a closure member arranged at least partially in the flow channel and reversibly transferrable between an open position and a closed position such as to open or close the flow channel through the valve housing, a non-electrically driven actuator mechanism operatively coupled to the closure member for transferring the closure member at least from the open position in the closed position, wherein the actuator mechanism is configured to be activated by a fluid flow through the flow channel reaching or exceeding a switching temperature and/or switching flow rate during operation, and at least one position indicator to indicate whether the closure member is in the open position or in the closed position, wherein the position indicator comprises at least one indicator member movably arranged in or at the valve housing between a first position and a second position, wherein the indicator member is magnetically coupled to the closure member such that the indicator member is magnetically transferred into the first position when the closure member is transferred into the open position, and into the second position when the closure member is transferred into the closed position, wherein the non-electrically driven actuator mechanism comprises an actuator spring assembly operatively coupled to the closure member and arranged in the flow channel such as to be in direct contact with a fluid flowing through the flow channel during operation, wherein the spring assembly comprises a shape-memory material and is configured to change its shape upon reaching or exceeding a switching temperature due to heating by the fluid, thereby transferring the closure member from the open position in the closed position, and wherein the actuator spring assembly comprises a stack of star washers each of which comprises a washer ring and at least three spring arms extending in a star-shaped manner radially outward from the washer ring, wherein upon reaching or exceeding the switching temperature each star washer experiences a specific axial expansion along a length axis of the stack due to its arms bending in a direction transverse to a plane defined by the washer ring.
2 . The stop valve according to claim 1 , wherein the indicator member is visible from outside the valve housing when being in at least one of the first position or the second position.
3 . The stop valve according to claim 1 , wherein the indicator member is magnetically coupled to the closure member directly or indirectly.
4 . The stop valve according to claim 1 , wherein the indicator member and/or an indicator coupling element fixedly coupled to the indicator member comprises a permanent-magnetic material.
5 . The stop valve according to claim 4 , wherein the indicator member and/or the indicator coupling element fixedly coupled to the indicator member comprises a neodymium-iron-boron permanent magnet or samarium-cobalt permanent magnet.
6 . The stop valve according to claim 1 , wherein the indicator member has a ball shape.
7 . The stop valve according to claim 1 , wherein the indicator member is moveably guided between the first position and the second position in a guide cage.
8 . The stop valve according to claim 7 , wherein the guide cage comprises at least one inspection window configured and arranged to release a view on the indicator member from outside the valve housing when the indicator member is in at least one of the first position or the second position.
9 . The stop valve according to claim 1 , wherein the closure member and/or a closure coupling element fixedly coupled to the closure member comprises a magnetic material.
10 . The stop valve according to claim 1 , wherein the valve housing is made of a non-magnetic material.
11 . The stop valve according to claim 1 , wherein the star washers are arranged such that the arms of neighboring star washers bend in opposite directions.
12 . The stop valve according to claim 1 , wherein a number of star washers forming the stack is chosen such that a sum over the specific free axial expansions of all the star washers is at least 110 percent of a stroke length of the closure member between the open position and the closed position and/or at most 150 percent of a stroke length of the closure member between the open position and the closed position.
13 . The stop valve according to claim 1 , further comprising at least one support ring between each pair of neighboring star washers or between each pair of neighboring star washers, the arms of which bend towards each other upon reaching or exceeding the switching temperature.
14 . The stop valve according to claim 7 , wherein the guide cage comprises at least one open inspection window configured and arranged to release a view on the indicator member from outside the valve housing when the indicator member is in at least one of the first position or the second position.
15 . The stop valve according to claim 1 , wherein the valve housing is made of an austenitic stainless steel.
16 . The stop valve according to claim 1 , wherein a number of star washers forming the stack is chosen such that a sum over the specific free axial expansions of all the star washers is from 110 percent to 150 percent of a stroke length of the closure member between the open position and the closed position.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a US National Stage Application of PCT International Patent Application No. PCT/EP2020/084974, filed Dec. 8, 2020, which claims the benefit of priority to European Patent Application No. 19214504.3, filed Dec. 9, 2019, which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. FIELD The present invention relates to a stop valve for installation in a pipeline, in particular in a pipeline of a nuclear facility, such as a nuclear power plant, or in a conventional chemical reactor and in a conventional power plant, in order stop a fluid flow through the pipeline in the event of an operational failure. BACKGROUND In many industrial facilities pipelines passing through different areas of the facility may be fitted with so-called stop valves to immediately stop a fluid flow through the pipeline in the event of an operational failure and, thus, to prevent an undesired fluid leakage in areas downstream of the valve. For example in nuclear power plants, pipelines may pass through the reactor containment to fluidly couple the primary coolant circuit inside the containment with a measuring or sampling device outside the containment. As a standard, such pipelines may be fitted with stop valves in order to prevent radioactivity, humidity, loss of cooling fluid and loss of system pressure from escaping in areas outside the containment in the event of an excessive fluid temperature and/or flow rate in the pipeline. Such excessive temperature and/or flow rate conditions may be due to an operational failure, such as a pipeline leak inside or outside the reactor containment. Mostly, stop valves are actively controlled and actuated in order to properly close in the event of an operational failure. However, in case the power supply for the active control and actuation fails, proper function of the actively controlled valve is no longer guaranteed. Alternatively, stop valves may be configured to close in a passive manner in the event of an operational failure. Such valves may comprise an actuator mechanism for transferring a closure member of the valve into a closed position which is automatically activated at a critical temperature or peak pressure of the fluid flowing through the valve. For example, as described in WO 2017/042189 A1, the activation mechanism may comprise an actuator spring assembly comprising a shape-memory material which changes its shape upon reaching or exceeding a switching temperature due to heating by the fluid and, thus, transfers a closure member from an open position into the closed position. For determining whether the valve is in a closed or in an open position, position sensors may be provided at the valve which determine the current position of the closure member. Typically, such position sensors are capacitive or inductive sensors. Advantageously, capacitive or inductive sensors may be read out remotely from a control center. However, these sensor types necessarily require an electrical power supply and, thus, are also prone to failure in case of a power breakdown. In addition, these sensor types require some means for data processing, in particular for converting and displaying the sensor signal, in order to be able to indicate the actual valve position at all. Therefore, it is an object of the present invention to provide a stop valve for installation in a pipeline which reliably closes in a passive manner and allows for reliably determining whether the valve is in a closed or in an open position. This object is achieved by a stop valve according to independent claim 1. Advantageous embodiments of the invention are subject of the dependent claims. SUMMARY According to a first aspect of the invention, there is provided a stop valve for installation in a pipeline, in particular in a pipeline of a nuclear facility, such as a nuclear power plant, or in a conventional chemical reactor and in a conventional power plant, in order stop a fluid flow through the pipeline in the event of an operational failure, for example, in the event of a pipeline leak. The stop valve comprises a valve housing including a flow channel passing through the valve housing. The stop valve further comprises a closure member which is arranged at least partially in the flow channel and reversibly transferrable between an open position and a closed position such as to open or close the flow channel through the valve housing. Furthermore, the stop valve comprises a non-electrically driven actuator mechanism operatively coupled to the closure member for transferring the closure member at least from the open position in the closed position. The actuator mechanism is configured to be activated by a fluid flow through the flow channel reaching or exceeding a switching temperature and/or switching flow rate during operation. The actuator mechanism is configured to be automatical