Overflow valve for LNG (Liquefied Natural Gas)
By designing an overflow valve built into the LNG pipeline and adopting a valve body, valve seat, valve disc and spring structure, the problems of the overflow valve occupying a large space and the sealing ring being easily damaged are solved, thus achieving compact layout and high-safety LNG production.
Patent Information
- Application Number
- CN202422988373.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2034-12-04
AI Technical Summary
The installation of overflow valves in existing LNG production takes up a lot of space, and the sealing rings are easily damaged, resulting in many leakage points and affecting production safety.
A flow control valve that can be built into the LNG pipeline is designed. The valve body, valve seat, valve disc and spring structure are used. The valve body is sealed by girth welding to reduce the number of joints and eliminate the sealing ring, thus achieving a compact layout and improving the sealing performance.
The LNG pipeline layout is made more compact, leakage points are greatly reduced, production safety is improved, and the probability of leakage is reduced.
Smart Images
Figure CN223424715U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of LNG production, in particular to an overflow valve for LNG. Background Art
[0002] The overflow valve is a critical component in liquefied natural gas (LNG) production. It's used to limit the outlet flow rate in the event of an abnormal disconnection in the rear end of the LNG pipeline, preventing large amounts of media from leaking out of the pipeline and providing rapid protection. Existing overflow valves require connectors at both ends of the valve to connect to the LNG pipeline. Since these valves are installed externally to the LNG pipeline, they occupy a significant amount of space during LNG pipeline layout. Furthermore, sealing rings are required at the connections between the overflow valve and the connector, and between the connector and the LNG pipeline. These rings are easily damaged during use, resulting in numerous leaks when the overflow valve is installed in the LNG pipeline, impacting the safety of LNG production. Utility Model Content
[0003] The utility model aims to provide an LNG overflow valve with a compact structure and few leakage points.
[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: an LNG overflow valve, comprising a cylindrical valve body that can be inserted into an LNG pipeline, a valve cavity being arranged inside the valve body, a valve body outlet being arranged at one end of the valve body and communicating with the valve cavity, a placement port being arranged at the other end of the valve body and communicating with the valve cavity, a valve cavity near the valve body outlet being reduced in diameter to form a valve body sealing surface, a valve seat and a valve disc being arranged in the valve body valve cavity, the valve disc having a head and a rod, a valve disc sealing surface being arranged at the head of the valve disc and contacting and sealing with the valve body sealing surface, and an outer peripheral wall of the valve body between the valve seat and the valve body sealing surface. A plurality of liquid inlet holes connected to the valve cavity of the valve body are circumferentially arranged on the upper edge. The liquid inlet holes, the gap between the valve disc head and the valve body sealing surface, and the valve body outlet together constitute a flow channel. The stem of the valve disc passes through the valve seat toward the valve body installation port and is installed with a spring seat. A spring is arranged between the spring seat and the valve seat. The two ends of the spring respectively press against the spring seat and the valve seat. Under the elastic force of the spring, the valve disc always has a tendency to move toward the valve body installation port so that the valve disc sealing surface leaves the valve body sealing surface to open the flow channel. A limit ring is provided on the inner wall of the valve cavity at the valve body installation port end to prevent the valve disc from falling out of the valve body.
[0005] Furthermore, in the aforementioned LNG overflow valve, a plurality of through holes communicating with the valve cavity are circumferentially provided on the outer peripheral wall of the valve body between the limit retaining ring and the valve body installation port.
[0006] Furthermore, in the aforementioned LNG overflow valve, the valve disc sealing surface at the valve disc head is a spherical sealing surface.
[0007] Furthermore, in the aforementioned LNG overflow valve, the spring seat and the valve disc stem are connected together by threads.
[0008] Furthermore, in the aforementioned LNG overflow valve, a ring groove is provided on the outer peripheral wall of the valve disc stem near the valve body installation port, and an open retaining ring is clamped in the ring groove for limiting the spring seat.
[0009] Furthermore, in the aforementioned LNG overflow valve, the specific installation structure of the valve seat in the valve body cavity is as follows: the inner wall of the valve body cavity is reduced in diameter to form a step surface, and the valve seat is pressed against the step surface of the valve body cavity by the action of a spring.
[0010] Furthermore, in the aforementioned LNG overflow valve, an air vent is provided on the side wall of the valve seat, which radially penetrates the side wall of the valve seat. The air vent connects the gap between the valve seat and the inner wall of the valve body, as well as the valve cavity.
[0011] Through the implementation of the above technical solutions, the beneficial effects of the present invention are as follows: (1) the overflow valve can be directly built into the LNG pipeline, making the LNG pipeline layout more compact; (2) after the overflow valve is built into the LNG pipeline and the outlet end of the overflow valve is welded and sealed with the pipe mouth of the LNG pipeline, there is only one connection between the overflow valve and the LNG pipeline, which greatly reduces the leakage points compared with the four connections of the traditional overflow valve, thereby improving the safety of LNG production; (3) the traditional sealing ring sealing structure is eliminated, which further reduces the probability of leakage points and further improves the safety of LNG production. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a schematic structural diagram of the LNG overflow valve described in the present utility model.
[0013] Figure 2 for Figure 1 Schematic diagram of the structure of the AA section shown in.
[0014] Figure 3 It is a cross-sectional diagram of the valve body.
[0015] Figure 4 Schematic diagram of the valve disc structure. DETAILED DESCRIPTION
[0016] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
[0017] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4As shown, the LNG overflow valve comprises a cylindrical valve body 1 which can be inserted into the LNG pipeline, a valve cavity 2 being provided inside the valve body 1, both ends of the valve body 1 being flat end faces, a valve body outlet 3 being provided at one end of the valve body 1 being connected to the valve cavity 2, a placement port 4 being provided at the other end of the valve body 1 being connected to the valve cavity 2, a valve cavity diameter change near the valve body outlet 3 forming a valve body sealing surface 5, a valve seat 6 and a valve disc 7 being provided in the valve body valve cavity 2, the valve disc 7 having a head 71 and a rod 72, the diameter of the head 71 being larger than the diameter of the rod 72, and the head 71 and the rod 72 being aligned with each other. The reduced diameter of the valve disc 72 forms an abutment surface 75, and a valve disc sealing surface 73 is provided on the head 71 of the valve disc 7 to cooperate with the valve body sealing surface 5 for sealing. The valve disc sealing surface 73 of the valve disc head 71 is a spherical sealing surface; a plurality of liquid inlet holes 8 communicating with the valve body valve cavity 2 are circumferentially provided on the outer peripheral wall of the valve body 1 between the valve seat 6 and the valve body sealing surface 5. Each liquid inlet hole 8, the gap 9 between the valve disc head 71 and the valve body sealing surface 5, and the valve body outlet 3 together constitute a flow passage. The stem 72 of the valve disc 7 passes through the valve seat 6 toward the valve body installation port 4 and is installed A spring seat 10 is provided between the spring seat 10 and the valve seat 6. The two ends of the spring 11 are respectively against the spring seat 10 and the valve seat 6. The valve disc 7 always has a tendency to move toward the valve body installation port under the elastic force of the spring 11, so that the valve disc sealing surface 73 leaves the valve body sealing surface 5 to open the flow channel. A limit ring 12 is provided on the inner wall of the valve cavity 2 at the valve body installation port end to prevent the valve disc 7 from falling out of the valve body 1; in this embodiment, a plurality of connecting valve cavities are provided along the circumferential direction on the outer peripheral wall of the valve body 1 between the limit ring 12 and the valve body installation port 4. 2, when the placement port 4 end of the overflow valve is aligned and inserted into the LNG pipeline until the end face of the valve body outlet of the overflow valve body 1 is flush with the pipe opening of the LNG pipeline, the outer peripheral wall of the valve body outlet end of the overflow valve body is girth-welded and sealed with the inner wall of the pipe opening of the LNG pipeline. When the LNG in the LNG pipeline flows through the overflow valve and out of the valve body outlet 3, the LNG will enter the valve cavity 2 from the through holes 13 and the placement port 4 and act on the valve disc 7. In this way, when the rear end pipeline of the LNG pipeline is abnormally disconnected, the valve disc 7 can respond more sensitively.
[0018] In this embodiment, the spring seat 10 and the valve disc stem 72 are connected together by a threaded connection, which not only makes assembly more convenient, but also allows the distance between the spring seat 10 and the valve seat 6 to be adjusted by rotating the spring seat 10, thereby adjusting the elastic force of the spring 11, and thus adjusting the reaction sensitivity of the valve disc 7 when the rear end pipeline is abnormally disconnected; an annular groove 74 is provided on the outer peripheral wall of the valve disc stem 72 near the valve body installation opening 4, and an open retaining ring 14 for limiting the spring seat 10 is clamped in the annular groove 74. The open retaining ring 14 can limit the spring seat 10 to prevent the spring seat 10 from separating from the valve disc 72 during use, thereby improving the overall stability of the excess flow valve;
[0019] In this embodiment, the specific installation structure of the valve seat 6 in the valve body cavity 2 is as follows: the inner wall of the valve body cavity 2 is reduced in diameter to form a step surface 15, and the valve seat 6 is pressed against the step surface 15 of the valve body cavity 2 by the action of the spring 11. In this way, the valve seat 6 does not need to be welded to the valve body, and can be supported by the spring 11, so that the valve seat 6 can be easily disassembled and assembled; in this embodiment, a vent hole 16 is provided on the side wall of the valve seat 6, which radially passes through the side wall of the valve seat 6. The vent hole 16 connects the gap between the valve seat 6 and the inner wall of the valve body 1 and the valve cavity 2. In this way, when LNG enters the gap between the valve seat 6 and the inner wall of the valve body 1, the LNG entering the gap can directly flow into the valve cavity 2 without accumulating in the gap, thereby avoiding the deformation of the valve seat and valve body caused by the vaporization of LNG accumulated in the gap, further improving the overall stability of the excess flow valve and extending the service life of the excess flow valve as a whole;
[0020] During installation, align the installation port of the overflow valve and insert it into the LNG pipeline until the flat end surface of the valve body outlet end of the overflow valve body 1 is flush with the pipe mouth of the LNG pipeline, and then the outer peripheral wall of the valve body outlet end of the overflow valve is circumferentially welded and sealed with the inner wall of the pipe mouth of the LNG pipeline, thereby completing the installation of the overflow valve in the LNG pipeline; since the overflow valve is directly built into the LNG pipeline, the LNG pipeline is more compact when arranged, and since there is only one connection between the overflow valve and the LNG pipeline, compared with the four connections of the traditional overflow valve, the leakage points are greatly reduced, and the safety of LNG production is improved; and there is no need to use sealing rings to seal the connections, which further reduces the probability of leakage points and further improves the safety of LNG production.
[0021] Under normal conditions, when LNG in the LNG pipeline flows through the overflow valve, the LNG will sequentially pass through the gap between the LNG pipeline and the overflow valve body, the various liquid inlet holes 8 of the overflow valve, the gap 9, and the valve body outlet 3 before smoothly passing through the overflow valve. Furthermore, during the process of LNG flowing through the overflow valve, the LNG in the LNG pipeline will enter the valve chamber 2 through the various through holes 13 and the installation port 4 and act on the valve disc 7. Because under normal conditions, the force applied by the spring 11 to the valve disc 7 is greater than the force applied by the LNG to the valve disc 7, the valve disc 7, under the elastic force of the spring 11, will move toward the valve body installation port 4 until the abutment surface 75 abuts against the valve seat 6, so that the valve disc 7 is always in a state where the valve disc sealing surface 73 is away from the valve body sealing surface 5 to open the overflow channel.
[0022] When the back end pipeline of the LNG pipeline is abnormally disconnected, the pressure difference before and after the valve disc of the overflow valve suddenly increases, the flow through the overflow valve suddenly increases greatly, at this time, the force of LNG on the valve disc 7 will be greater than the reaction force of the spring in the normal state, at this time, the valve disc 7 will move to the valve body sealing surface 5 against the force of the spring 11, in the process of the valve disc 7 moving to the valve body sealing surface 5, the overflow passage area will be gradually reduced, until the valve disc sealing surface 73 of the valve disc 7 contacts the sealing valve body sealing surface 5, then the overflow passage is cut off, thereby closing the valve body outlet of the overflow valve, preventing a large amount of LNG from flowing out, thereby limiting the outlet flow size, and playing a rapid protection role.
[0023] The utility model discloses the advantages are: (1) this overflow valve can be directly built -in in LNG pipeline, make LNG pipeline arrangement more compact, (2) this overflow valve is built -in in LNG pipeline and will overflow valve export and LNG pipeline pipe mouth ring weld seal after, and the overflow valve and LNG pipeline only exist a connecting place, compared with four connecting places of traditional overflow valve, greatly reduce the leakage point, improve the safety of LNG production, (3) the traditional sealing ring sealing structure is saved, and the leakage point occurrence probability is further reduced, and the safety of LNG production is further improved.
[0024] The above only is the preferred embodiment of the utility model, is not any other form's limitation to the utility model, and according to the technical essence of the utility model, any modification or equivalent change is made, still belongs to the range of the utility model required protection.
Claims
1. LNG overflow valve, characterized by: The utility model comprises a cylindrical valve body which can be inserted into the LNG pipeline, a valve cavity is arranged inside the valve body, a valve body outlet communicating with the valve cavity is arranged at one end of the valve body, and a placement port communicating with the valve cavity is arranged at the other end of the valve body. The valve cavity near the valve body outlet is reduced in diameter to form a valve body sealing surface, a valve seat and a valve disc are arranged in the valve body valve cavity, the valve disc has a head and a rod, a valve disc sealing surface for cooperating with the valve body sealing surface for contact sealing is arranged on the valve disc head, and a plurality of valves communicating with the valve body valve cavity are arranged circumferentially on the outer peripheral wall of the valve body between the valve seat and the valve body sealing surface. The liquid inlet hole, the gap between each liquid inlet hole, the valve disc head and the valve body sealing surface, and the valve body outlet together constitute a flow channel. The stem of the valve disc passes through the valve seat toward the valve body installation port and is installed with a spring seat. A spring is arranged between the spring seat and the valve seat. The two ends of the spring respectively press against the spring seat and the valve seat. Under the elastic force of the spring, the valve disc always has a tendency to move toward the valve body installation port so that the valve disc sealing surface leaves the valve body sealing surface to open the flow channel. A limit ring is provided on the inner wall of the valve cavity at the valve body installation port end to prevent the valve disc from falling out of the valve body.
2. The LNG overflow valve according to claim 1, characterized in that: A plurality of through holes communicating with the valve cavity are circumferentially arranged on the outer peripheral wall of the valve body between the limiting retaining ring and the valve body installation port.
3. The LNG overflow valve according to claim 1, characterized in that: The valve disc sealing surface on the valve disc head is a spherical sealing surface.
4. The LNG overflow valve according to claim 1, characterized in that: The spring seat and the valve disc stem are connected together through threads.
5. The LNG overflow valve according to claim 1, characterized in that: An annular groove is provided on the outer peripheral wall of the valve disc stem portion close to the valve body installation opening, and an open retaining ring for limiting the spring seat is clamped in the annular groove.
6. The LNG overflow valve according to claim 1, characterized in that: The specific installation structure of the valve seat in the valve body cavity is as follows: the inner wall of the valve body cavity is reduced in diameter to form a step surface, and the valve seat is pressed against the step surface of the valve body cavity by the action of the spring.
7. The LNG overflow valve according to any one of claims 1 to 6, characterized in that: An air vent is provided on the side wall of the valve seat and radially penetrates the side wall of the valve seat. The air vent connects the gap between the valve seat and the inner wall of the valve body, as well as the valve cavity.