A gate valve that can suppress boiler effect and a method for using the same

Abstract

This invention discloses a gate valve capable of suppressing the boiler effect and its usage method, belonging to the field of nuclear power valves. The gate valve body and seat have guide grooves on the dead-end section side to guide bubbles generated by boiling in the dead-end section from low to high to the pressure relief structure. The main structure of the pressure relief structure is a three-way structure, including a horizontal channel and a top vertical channel. The horizontal channel communicates with the dead-end section of the gate valve. The upper inner wall of the vertical channel has a tapered cylindrical surface that gradually narrows from top to bottom. A matching tapered component is placed inside the tapered cylindrical surface. When the tapered component is at its lower limit position, it can completely seal the bottom of the tapered cylindrical surface to achieve a seal in the vertical channel. A perforated top cover is threaded onto the top of the vertical channel, and a spring that is always in a vertically compressed state is provided between the top cover and the top of the tapered component. The structure proposed in this invention can suppress the boiler effect, prevent corrosion of the gate valve sealing surface, and avoid the destruction of the double isolation of the system pressure boundary.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power valves, specifically relating to a gate valve that can suppress the boiler effect and its usage method. Background Technology

[0002] In the piping systems of nuclear power plants, such as waste heat removal systems, reactor coolant systems, and chemical and volume control systems, there are situations where two gate valves are needed to create a double pressure boundary for isolation between high-pressure and low-pressure pipelines. Between the two gate valves lies a section of pipe where fluid does not flow, known as a "dead pipe section." When the temperature of the isolated side of the pipe is higher, the fluid on the higher-temperature side may heat the water in the dead pipe section through the gate valve, causing the water in the dead pipe section to boil. Bubbles rise and burst on the upper side of the gate valve, leading to corrosion of the inner wall of the pipe or the sealing surface of the gate valve—a phenomenon known as the "dead pipe section boiler effect." The dead pipe section boiler effect can cause problems such as internal valve leakage, breach of pressure boundaries, and radiation leakage, posing significant safety hazards.

[0003] According to research, one solution to the "dead tube section boiler effect" in nuclear power plants (CN 113932153 A) involves introducing high-pressure fluid into the dead tube section to increase the water pressure and thus prevent boiling. While this method can simply and effectively avoid corrosion problems caused by boiling, it violates the original design principle of "double isolation at the pressure boundary," turning the original double isolation into a single isolation, thereby increasing safety hazards.

[0004] Therefore, there is an urgent need for a gate valve and its usage method that can suppress the boiler effect, prevent corrosion of the gate valve sealing surface, and avoid the destruction of the double isolation of the system pressure boundary. Summary of the Invention

[0005] The purpose of this invention is to overcome the deficiencies in the prior art and provide a gate valve that can suppress the boiler effect and its usage method. This invention, without compromising the double isolation of the system pressure boundary, guides boiling bubbles in the dead section away from the gate sealing surface through a combination of a flow guide structure and a pressure relief structure, and automatically releases pressure when the pressure exceeds the pressure relief threshold.

[0006] The specific technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a gate valve that can suppress the boiler effect, comprising a valve body, a valve stem, a gate, and a valve seat. The valve body and the valve seat are provided with a flow guide groove on the dead pipe section side of the gate valve. One end of the flow guide groove is in contact with the end side of the gate, and the other end is in contact with the vertical channel of the pressure relief structure, which is used to guide the bubbles generated by boiling in the dead pipe section from low to high to the pressure relief structure for pressure relief. The pressure relief structure is connected to the dead section of the gate valve and includes a main structure, a top cover, a conical component, and a spring. The main structure is a three-way structure, including a horizontal channel and a vertical channel at the top. The horizontal channel is connected to the dead section of the gate valve. The upper inner wall of the vertical channel has a tapered cylindrical surface that gradually narrows from top to bottom. A matching tapered component is placed inside the tapered cylindrical surface. When the tapered component is at its lower limit position, it can completely seal the bottom of the tapered cylindrical surface to achieve a seal of the vertical channel. A top cover with an opening is threaded onto the top of the vertical channel. A spring that is always in a vertically compressed state is provided between the top cover and the top of the tapered component.

[0007] Preferably, the flow guide groove is formed at the top of the valve seat and the corresponding valve body flow channel, and the height of the end near the gate is lower than the height of the end near the pressure relief structure.

[0008] Preferably, the diameter of the horizontal channel is the same as the inner diameter of the dead pipe section and the outlet inner diameter of the gate valve.

[0009] Preferably, the pressure relief structure is sealed and fixed to the dead pipe section by welding or flange connection.

[0010] Preferably, the top cover has a through hole in the center; the conical component is a truncated cone structure of revolution, and its top diameter is smaller than the diameter of the largest part of the conical cylinder, but larger than the diameter of the through hole in the center of the top cover.

[0011] Preferably, the tapered member and the tapered cylindrical surface have the same inclination.

[0012] Preferably, the top outlet of the vertical channel receives the collection container.

[0013] Secondly, the present invention provides a method for using a gate valve capable of suppressing boiler effects as described in any of the first aspects, as follows: Seal and fix the horizontal channel of the main structure of the pressure relief structure to the pipe on the dead pipe section side of the gate valve, so that the vertical channel is in a vertically upward state; place the conical part with the conical surface facing down in the conical cylindrical surface; place the spring vertically above the conical part and cover it with the top cover, so that the spring is in a compressed state; adjust the initial downward pressure of the spring by adjusting the screw depth of the top cover in the vertical channel, and then set the pressure relief threshold. When the water in the dead pipe section is heated and boils, the generated bubbles will flow from low to high along the guide groove at the top of the valve seat and valve body flow channel on the dead pipe section side of the gate valve to the pressure relief structure, preventing the bubbles from rupturing and corroding the gate plate. During this process, when the water in the dead pipe section continues to be heated and boils, the generated gas will increase continuously, causing the pressure to be too high and exceed the pressure relief threshold. At this time, the conical part in the vertical channel will move upward, so that a gap flow channel is formed between the outer wall of the conical part and the inner wall of the vertical channel. The high-pressure gas will flow along the gap flow channel from the through hole opened on the top cover to the external collection container, completing the pressure relief and preventing the pressure from being too high.

[0014] Compared with the prior art, the present invention has the following advantages: This invention utilizes the buoyancy of air bubbles by creating upward-flowing guide grooves at the top of the valve seat and valve body flow channel, actively guiding them to the pressure relief structure above. This prevents air bubbles from stagnating and collapsing near the gate sealing surface, effectively preventing corrosion and damage to the sealing surface caused by cavitation. When the pressure in the dead pipe section exceeds the pressure relief threshold, the gate valve and its usage method proposed in this invention can also automatically relieve pressure, ensuring the safety of the dead pipe section. Simultaneously, this invention does not introduce high-pressure fluid into the dead pipe section, ensuring double isolation of the system pressure boundary. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a gate valve structure that can suppress the boiler effect according to a preferred embodiment of the present invention; wherein, Figure (a) is a cross-sectional view and Figure (b) is an oblique cross-sectional view of the outlet side; Figure 2 This is a schematic diagram of a pressure relief structure according to a preferred embodiment of the present invention; wherein, Figure (a) is a sectional view and Figure (b) is an isometric view; The attached figures are labeled as follows: valve body 1, valve stem 2, gate 3, valve seat 4, pressure relief structure 5, main structure 51, top cover 52, conical part 53, and spring 54. Detailed Implementation

[0016] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the present invention can be combined accordingly without mutual conflict.

[0017] like Figure 1 As shown in (a), this invention provides a gate valve capable of suppressing the boiler effect. In addition to the conventionally configured valve body 1, valve stem 2, gate 3, and valve seat 4, it innovatively incorporates a flow guide groove and a pressure relief structure 5. In this embodiment, Figure 1 In (a), the left side of the gate valve is the high-temperature and high-pressure side, while the right side is the dead-end section side. The valve body 1 and valve seat 4 have flow guide grooves on the dead-end section side of the gate valve, such as... Figure 1 As shown in (b), one end of the guide channel contacts the end side of the gate 3, and the other end contacts the vertical channel of the pressure relief structure 5, which is used to guide the bubbles generated by boiling in the dead tube section from low to high to the pressure relief structure 5 for pressure relief.

[0018] In a preferred embodiment of the present invention, a flow guide groove is formed at the top of the flow channel of the valve seat 4 and the corresponding valve body 1, and its extension direction is from low to high towards the pressure relief structure 5. That is, the height of the end near the gate plate 3 is lower than the height of the end near the pressure relief structure 5. This inclined structure can guide the bubbles generated by boiling in the dead tube section to the pressure relief structure 5.

[0019] In the gate valve of this invention, the pressure relief structure 5 is installed on the dead section side of the gate valve and is fixedly connected to the valve body 1. The connection between the pressure relief structure 5 and the gate valve body should ensure a sealing effect; the connection method can be welding or flange connection, etc. Figure 2 As shown, the pressure relief structure 5 mainly includes a main structure 51, a top cover 52, a conical component 53, and a spring 54. Specifically, the main structure 51 is a three-way structure, including a horizontal channel 9 (main channel) and a vertical channel at the top (branch channel). The horizontal channel is connected to the dead pipe section of the gate valve. The upper inner wall of the vertical channel has a conical cylindrical surface with a gradually decreasing inner diameter from top to bottom. A matching conical component 53 is placed inside the conical cylindrical surface. When the conical component 53 is at its lower limit position, it can completely seal the bottom of the conical cylindrical surface to achieve a seal in the vertical channel. A top cover 52 with an opening is threaded onto the top opening of the vertical channel. A spring 54 is provided between the top cover 52 and the top of the conical component 53. The spring 54 is vertically positioned and always in a compressed state, which can press the conical component 53 tightly against the conical cylindrical surface on the inner wall of the vertical channel to form a seal.

[0020] In a preferred embodiment of the present invention, the horizontal channel of the main structure 51 has the same pipe inner diameter as the dead pipe section and the outlet inner diameter of the gate valve, which is 174 mm.

[0021] In a preferred embodiment of the present invention, the top outlet of the vertical channel receives the collection container. In actual use, the gas can flow out to the collection container through the opening on the top cover 52.

[0022] In a preferred embodiment of the present invention, the conical member 53 is a frustum of revolution structure, and its outer circumferential surface has a conical surface that matches the conical cylindrical surface of the inner wall of the vertical channel and has the same slope. The angle between the inclined surface and the vertical direction can be 30°. Taking the central through hole of the top cover 52 as an example, the top diameter of the conical member 53 should be smaller than the diameter of the largest point of the conical cylindrical surface, but larger than the diameter of the central through hole at the top of the top cover 52, to prevent the conical member 53 from sliding out of the vertical channel. Specifically, the top diameter of the conical member 53 is 28 mm, the diameter of the largest point of the conical cylindrical surface is 36 mm, and the diameter of the central through hole at the top of the top cover 52 is 20 mm.

[0023] In addition to the gate valve described above that can suppress the boiler effect, the present invention also provides a method of using it, which is as follows: First, install the valve stem 2, gate 3, and valve seat 4 inside the valve body 1. Then, seal and fix the horizontal channel of the main structure 51 in the pressure relief structure 5 to the pipe on the dead pipe section side of the gate valve, ensuring that the vertical channel is in a vertically upward state.

[0024] Next, the conical part 53 is placed inside the conical cylindrical surface with the conical surface facing down.

[0025] Finally, spring 54 is placed vertically above conical member 53, and top cover 52 is placed on top to compress spring 54. The initial downward pressure of spring 54 is adjusted by adjusting the screw depth of top cover 52 in the vertical channel, thereby setting the pressure relief threshold.

[0026] In this embodiment, when the water in the dead pipe section is heated and boils, the generated bubbles will flow from low to high along the guide groove at the top of the flow channel between the valve seat 4 and the valve body 1 on the dead pipe section side of the gate valve to the pressure relief structure 5, preventing the bubbles from rupturing and corroding the gate plate 3, and preventing the gate valve sealing surface from being affected by cavitation. During this process, when the water in the dead pipe section continues to be heated and boils, the generated gas continuously increases, causing the pressure to become too high and exceed the pressure relief threshold. The force acting on the conical member will be greater than the spring pressure, and the pressure will push the conical member 53 in the vertical channel upward, so that a gap flow channel is formed between the outer wall surface of the conical member 53 and the inner wall surface of the vertical channel. At this time, the high-pressure gas will flow along the formed gap flow channel from the through hole opened on the top cover 52 to the external collection container, completing the pressure relief and preventing the pressure from becoming too high. The structure proposed in this invention can suppress the boiler effect and prevent the gate valve sealing surface from being corroded, while avoiding the destruction of the double isolation of the system pressure boundary.

[0027] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A gate valve capable of suppressing boiler effect, comprising a valve body (1), a valve stem (2), a gate (3), and a valve seat (4), characterized in that, The valve body (1) and valve seat (4) are provided with a flow guide groove on the dead pipe section side of the gate valve; one end of the flow guide groove is in contact with the end side of the gate plate (3), and the other end is in contact with the vertical channel of the pressure relief structure (5), which is used to guide the bubbles generated by boiling in the dead pipe section from low to high to the pressure relief structure (5) for pressure relief; The pressure relief structure (5) is connected to the dead pipe section of the gate valve and includes a main structure (51), a top cover (52), a conical part (53), and a spring (54). The main structure (51) is a three-way structure, including a horizontal channel and a vertical channel at the top. The horizontal channel is connected to the dead pipe section of the gate valve. The upper inner wall of the vertical channel is provided with a conical cylindrical surface that gradually narrows from top to bottom. A matching conical part (53) is placed inside the conical cylindrical surface. When the conical part (53) is at the lower limit position, it can completely seal the bottom of the conical cylindrical surface to achieve the sealing of the vertical channel. The top of the vertical channel is threaded with a top cover (52) with an opening. A spring (54) that is always in a vertical compression state is provided between the top cover (52) and the top of the conical part (53).

2. The gate valve for suppressing boiler effect according to claim 1, characterized in that, The flow guide groove is opened at the top of the flow channel of the valve seat (4) and the corresponding valve body (1), and the height of the end near the gate (3) is lower than the height of the end near the pressure relief structure (5).

3. A gate valve for suppressing boiler effect according to claim 1, characterized in that, The diameter of the horizontal channel is the same as the inner diameter of the dead pipe section and the outlet inner diameter of the gate valve.

4. A gate valve for suppressing boiler effect according to claim 1, characterized in that, The pressure relief structure (5) is sealed and fixed to the dead pipe section by welding or flange connection.

5. A gate valve for suppressing boiler effect according to claim 1, characterized in that, The top cover (52) has a through hole in the center; the conical part (53) is a truncated cone structure of revolution, and its top diameter is smaller than the diameter of the largest part of the conical cylinder, but larger than the diameter of the through hole in the center of the top of the top cover (52).

6. A gate valve for suppressing boiler effect according to claim 1, characterized in that, The conical component (53) and the conical cylindrical surface have the same inclination.

7. A gate valve for suppressing boiler effect according to claim 1, characterized in that, The top outlet of the vertical channel receives the collection container.

8. A method of using a gate valve capable of suppressing boiler effect as described in any one of claims 1 to 7, characterized in that, Specifically as follows: The horizontal channel of the main structure (51) in the pressure relief structure (5) is sealed and fixed to the pipe on the dead pipe section side of the gate valve, so that the vertical channel is in a vertically upward state; the conical part (53) is placed with the conical surface facing down in the conical cylindrical surface; the spring (54) is placed vertically above the conical part (53) and the top cover (52) is covered, so that the spring (54) is in a compressed state; by adjusting the screw depth of the top cover (52) in the vertical channel, the initial downward pressure of the spring (54) is adjusted, and then the pressure relief threshold is set; When the water in the dead pipe section is heated and boils, the generated bubbles will flow from low to high along the guide groove at the top of the flow channel of the gate valve dead pipe section side valve seat (4) and valve body (1) to the pressure relief structure (5), avoiding the bubbles from rupturing and corroding the gate plate (3); during this process, when the water in the dead pipe section continues to be heated and boils, the generated gas will increase continuously, causing the pressure to be too high and exceed the pressure relief threshold. The conical part (53) in the vertical channel will move upward, so that the outer wall surface of the conical part (53) and the inner wall surface of the vertical channel form a gap flow channel. The high pressure gas will flow along the gap flow channel from the through hole opened on the top cover (52) to the external collection container, completing the pressure relief and preventing the pressure from being too high.

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