A negative pressure pipeline working medium negative pressure protection and safe discharge device and method

Abstract

The present invention relates to a negative pressure pipeline working medium negative pressure protection and safety relief device and method, comprising: a sealing cover, the two ends of which are sealed to form a protective cavity; a ball valve, one end of which is in sealed communication with the sealed cavity via a pipeline, and the other end of which is in communication with a vacuum generator or a helium supply device; a first-level safety valve, one end of which is connected to the pipeline to be protected via a connecting pipeline, the first-level safety valve having a first trip pressure. The negative pressure pipeline working medium negative pressure protection and safety relief device and method can be used for negative pressure protection at connection points of helium cryogenic transmission pipelines exposed to air, and can provide protection when the pipeline is overpressured.

Description

Technical Field

[0001] The present invention relates to the technical field of large-scale superfluid helium cryogenic refrigeration, and in particular to a negative pressure pipeline working medium negative pressure protection and safe discharge device and method. Background Art

[0002] In large-scale superfluid helium cryogenic refrigeration systems, cryogenic helium transmission lines are responsible for transporting the cryogenic working fluid from the refrigerator to the load and recovering the cooling energy, completing the closed cycle. The saturation pressure of 2K saturated superfluid helium is 3129 Pa, far below atmospheric pressure. During operation, air can intrude into the cryogenic piping through connecting components, affecting the purity of the helium and, in turn, severely impacting the performance of the entire cryogenic system. Furthermore, the pressure in the negative pressure piping fluctuates dynamically with changes in the operating environment. For example, if a valve is accidentally closed, the increased pressure in the pipeline could create the risk of explosion, necessitating timely decompression of the pipeline. Summary of the Invention

[0003] To address the above-mentioned issues, one objective of the present invention is to provide a negative pressure protection and safety relief device for negative pressure pipeline working fluids. This device can be used to provide negative pressure protection at connection points of helium cryogenic transmission pipelines exposed to air, and can also provide protection against pipeline overpressure. Another objective of the present invention is to provide a negative pressure protection method for negative pressure pipeline working fluids.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] One aspect of the present invention provides a negative pressure pipeline working medium negative pressure protection and safety discharge device, comprising:

[0006] A sealing cover, wherein both ends of the sealing cover are sealed to form a protective cavity;

[0007] a ball valve, one end of which is in sealed communication with the sealed cavity via a pipeline, and the other end of which is in sealed communication with a vacuum generator or a helium supply device;

[0008] A first-level safety valve, one end of which is connected to the pipeline to be protected through a connecting pipeline, and the first-level safety valve has a first tripping pressure.

[0009] Furthermore, it also includes a secondary safety valve, one end of which is connected to the protection cavity through a pipeline, and the other end is connected to the recovery and purification system. The secondary safety valve has a second trip pressure, which is greater than the first trip pressure.

[0010] Furthermore, it also includes a blasting component, one end of which is connected to the pipeline to be protected through a pipeline, and the blasting component has a third tripping pressure, which is greater than the second tripping pressure.

[0011] Furthermore, it includes a three-way valve, a first end of the three-way valve is connected to the pipeline to be protected through a pipeline, a second end is connected to the first-level safety valve through a pipeline, and a third end is connected to the blasting assembly through a pipeline.

[0012] Furthermore, the protective cover includes a cylinder, a head, a sealing cover flange and a base flange. The head is used to seal the top of the cylinder, the sealing cover is welded to the bottom of the cylinder, and the base flange is fixedly connected to the sealing cover flange to seal the bottom of the cylinder.

[0013] Furthermore, a helium leak detection port is provided on the base flange, and the helium leak detection port is used to detect helium leakage in the protection cavity.

[0014] Furthermore, the first-level safety valve includes a first valve body and a first air inlet, a first exhaust port, a first valve core and a first trip controller arranged on the first valve body. The first air inlet is connected to the connecting pipeline, and the first exhaust port discharges helium into the protection cavity. The first trip controller is used to control the tripping of the first valve core according to the pressure conditions of the pipeline to be protected.

[0015] Furthermore, the secondary safety valve includes a second valve body and a second air inlet, a second exhaust port, a second valve core and a second start-up controller arranged on the second valve body. The second air inlet is connected to the protection cavity, and the second exhaust port is connected to the recovery and purification system. The second start-up controller is used to control the start-up of the first valve core according to the pressure conditions in the protection cavity.

[0016] Furthermore, a sealing ring is pressed between the base flange and the sealing cover flange.

[0017] Another aspect of the present invention further provides a method for negative pressure protection and safe discharge of working fluid in a negative pressure pipeline, based on the negative pressure protection and safe discharge device for working fluid in a negative pressure pipeline, comprising the steps of:

[0018] Open the ball valve, close the primary safety valve, the secondary safety valve and the blasting assembly;

[0019] The protective cavity is vacuumed through the ball valve and stops when the vacuum reaches a set value;

[0020] Filling the protection cavity with helium through the ball valve, wherein the purity of the helium is the same as that of the helium in the pipeline to be protected;

[0021] When negative pressure is formed in the pipeline to be protected, the helium in the protection cavity enters the pipeline to be protected under negative pressure;

[0022] When the pressure of the pipeline to be protected is greater than the first trip pressure, the first-level safety valve trips and exhausts air into the protection cavity through the first exhaust port;

[0023] When the pressure in the protection cavity is greater than the second trip pressure of the secondary safety valve, exhaust is discharged to the recovery and purification system through the second exhaust port;

[0024] When the primary safety valve or the secondary safety valve fails to trip in time due to a fault, the bursting disc trips when the third tripping pressure of the bursting disc is reached, and exhausts gas to the atmosphere for pressure relief.

[0025] The present invention has the following advantages due to the adoption of the above technical solution:

[0026] 1. The negative pressure protection and safety relief device for negative pressure pipeline working fluid provided by the present invention supplies helium (99.999%) of the same purity as that in the system into the sealing cover cylinder of the above-mentioned negative pressure protection and safety relief component for negative pressure pipeline working fluid through a ball valve. When the pipeline is operating under negative pressure, the helium in the sealing cover cylinder is sucked into the cryogenic transmission pipeline through the safety valve connecting thread. Since the amount of helium sucked in is very small and the purity of the helium in both is the same, air pollution to the helium circulation environment in the pipeline is effectively avoided.

[0027] 2. When pipeline pressure becomes excessively high during travel, the primary safety valve trips, allowing a small amount of helium to accumulate within the sealed housing. As pressure continues to rise, the secondary safety valve trips. If the safety valve fails, the rupture disc ruptures, releasing pressure to the atmosphere. This creates a parallel-stage protection mechanism and enhances the reliability of the safety relief system. The safely exhausted helium is discharged into a recovery system, creating a closed-loop recycling system that avoids helium waste and local environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those skilled in the art. The accompanying drawings are only used to illustrate the preferred embodiment and are not to be considered as limitations of the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components.

[0029] In the attached figure:

[0030] Figure 1 This is a schematic structural diagram from one angle of a negative pressure pipeline working medium negative pressure protection and safety relief device according to one embodiment;

[0031] Figure 2 This is a structural diagram of the negative pressure protection and safety relief device for the negative pressure pipeline working medium from another angle;

[0032] Figure 3This is a schematic diagram of the structure of the negative pressure pipeline working medium negative pressure protection and safety relief device after removing the sealing cover;

[0033] Figure 4 It is a structural diagram of the base flange;

[0034] Figure 5 It is a structural diagram of a first-stage safety valve. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0036] An embodiment of the present invention provides a negative pressure pipeline working medium negative pressure protection and safety relief device, comprising a sealing cover, a ball valve, and a first-level safety valve. The sealing cover is sealed at both ends to form a protective cavity; one end of the ball valve is in sealed communication with the sealed cavity via a pipeline, and the other end of the ball valve is in communication with a vacuum generator or a helium supply device; one end of the first-level safety valve is connected to the pipeline to be protected via a connecting pipeline, and the first-level safety valve has a first trip pressure. The negative pressure pipeline working medium negative pressure protection and safety relief device can be used for negative pressure protection at the connection point of a helium cryogenic transmission pipeline exposed to air, and provides protection against pipeline overpressure.

[0037] Example 1

[0038] like Figures 1 to 5 As shown, the negative pressure pipeline working medium negative pressure protection and safety relief device includes a sealing cover 1, a ball valve 2, and a first-level safety valve 8. The sealing cover 1 is sealed at both ends to form a protection cavity. One end of the ball valve 2 is in sealed communication with the protection cavity via a pipe, and the other end of the ball valve 2 is in communication with a vacuum generator or helium supply device via an interface 3. One end of the first-level safety valve 8 is connected to the pipeline to be protected (not shown) via a connecting pipe 4. The first-level safety valve 8 has a first trip pressure.

[0039] When the negative pressure pipeline working medium negative pressure protection and safety relief device is used for negative pressure protection, the ball valve 2 is opened, and the protection cavity is evacuated by the vacuum generating device. When the vacuum degree reaches the set value, the device stops, and helium is then flushed into the protection cavity. The purity of the helium is the same as that of the helium in the pipeline to be protected.

[0040] When the pipeline to be protected operates under negative pressure, the helium in the sealing cover 1 is drawn into the cryogenic transmission pipeline through the safety valve connection thread. Since the amount of helium drawn in is small and the purity of the helium in both is the same, air pollution of the helium circulation environment in the pipeline is effectively avoided. Therefore, the negative pressure pipeline working medium negative pressure protection and safety relief device can be used for negative pressure protection at the connection point of the helium cryogenic transmission pipeline exposed to air.

[0041] When the pressure of the pipeline to be protected is too high during the stroke, the first-level safety valve 8 is activated, and a small amount of helium can be stored in the sealing cover 1, thereby relieving the pressure of the cryogenic transmission pipeline and providing overpressure protection.

[0042] Furthermore, in order to make the overpressure protection more reliable, the negative pressure pipeline working medium negative pressure protection and safety relief device also includes a secondary safety valve 7, one end of the secondary safety valve 7 is connected to the protection cavity through a pipeline, and the other end is connected to the recovery and purification system (not shown in the figure). The secondary safety valve 7 has a second trip pressure, and the second trip pressure is greater than the first trip pressure.

[0043] When the pressure of the pipeline to be protected is too high during the stroke, the pipeline to be protected is connected in parallel with the connecting pipeline 4, and the two have the same pressure. The pressure in the pipeline to be protected is transmitted to the first-level safety valve 8 through the protected pipeline outlet pipe 4. When the pressure in the pipeline exceeds the pressure and is greater than the set value of the first-level safety valve 8, the first-level safety valve 8 trips and exhausts into the protection cavity through the safety valve exhaust port. When the pipeline continues to be overpressured, exhaust continues to be discharged into the protection cavity until the pressure in the protection cavity continues to rise and is greater than the set value of the second-level safety valve 7. The second-level safety valve 7 trips and the helium in the protection cavity is discharged to the recovery and purification system through the safety valve exhaust port.

[0044] Furthermore, it also includes a blasting component 6, one end of which is connected to the pipeline to be protected through a pipeline, and the blasting component 6 has a third tripping pressure, which is greater than the second tripping pressure.

[0045] When the first-stage safety valve 8 or the second-stage safety valve 7 fails to trip in time, since the bursting pressure of the bursting assembly 6 is slightly higher than the tripping pressure of the second-stage safety valve 7, when the tripping pressure of the bursting assembly 6 is reached, the bursting assembly 6 trips and exhausts gas to the atmosphere to relieve pressure, thereby avoiding the continuous increase in pressure in the protection cavity and the pipeline to be protected, causing a safety accident.

[0046] The negative pressure protection and safety relief assembly for negative pressure piping is simple and easy to install, utilizing threaded and flanged connections. When a tripped safety valve requires resetting or a bursting disc requires replacement, the valve can be reset or the disc replaced simply by removing the screws and flange.

[0047] To facilitate installation and connection, the negative pressure pipeline working medium negative pressure protection and safety relief device includes a three-way valve 5, the first end of the three-way valve 5 is connected to the pipeline to be protected through a pipeline, the second end is connected to the first-level safety valve 8 through a pipeline, and the third end is connected to the blasting assembly 6 through a pipeline.

[0048] In order to improve the sealing reliability of the sealing cover, the protective cover includes a cylinder 11, a head 12, a sealing cover flange 13, and a base flange 14. The head 12 is used to seal the top of the cylinder 11. The sealing cover 13 is welded to the bottom of the cylinder 11. The base flange 14 is fixedly connected to the sealing cover flange 13 to seal the bottom of the cylinder 11. The base flange 14 is provided with a mounting hole 142, through which the connecting pipe 4 is connected to the primary safety valve 8.

[0049] In order to improve the sealing performance of the protection cavity, a helium leak detection port 142 is further provided on the base flange 14 , and the helium leak detection port 142 is used to detect helium leakage in the protection cavity.

[0050] The base flange 14 is further provided with a helium leak detection port 141 for detecting helium leakage in the protective cavity. Two helium leak detection ports 141 can be provided, and the two helium leak detection ports 141 are symmetrically arranged on both sides of the base flange 14 .

[0051] The first-level safety valve 8 includes a first valve body and a first air inlet 81, a first exhaust port 82, a first valve core 83 and a first trip controller 4 arranged on the first valve body. The first air inlet 81 is connected to the connecting pipeline 4, and the first exhaust port 82 discharges helium into the protection cavity. The first trip controller 84 is used to control the tripping of the first valve core 83 according to the pressure conditions of the pipeline to be protected.

[0052] The secondary safety valve 7 includes a second valve body and a second air inlet 71, a second exhaust port 72, a second valve core 73 and a second start-up controller 74 arranged on the second valve body. The second air inlet 71 is connected to the protection cavity, and the second exhaust port 72 is connected to the recovery and purification system. The second start-up controller 74 is used to control the start-up of the first valve core 73 according to the pressure conditions in the protection cavity.

[0053] Another embodiment of the present invention further provides a method for negative pressure protection and safe discharge of working fluid in a negative pressure pipeline, based on the negative pressure protection and safe discharge device for working fluid in a negative pressure pipeline, comprising the steps of:

[0054] Open the ball valve 2, and close the primary safety valve 8, the secondary safety valve 7, and the blasting assembly 6;

[0055] The protective cavity is vacuumed through the ball valve 2 and stops when the vacuum reaches the set value;

[0056] The protection cavity is filled with helium through the ball valve 2, and the purity of the helium is the same as that of the helium in the pipeline to be protected;

[0057] When negative pressure is formed in the pipeline to be protected, the helium in the protection cavity enters the pipeline to be protected under negative pressure;

[0058] When the pressure of the pipeline to be protected is greater than the first trip pressure, the first safety valve 8 trips and exhausts air into the protection cavity through the first exhaust port 82;

[0059] When the pressure in the protection cavity is greater than the second tripping pressure of the secondary safety valve 7, the gas is exhausted to the recovery and purification system through the second exhaust port 72;

[0060] When the primary safety valve 8 or the secondary safety valve 7 fails to trip in time due to a fault, the bursting disc trips when the third tripping pressure of the blasting assembly 6 is reached, and exhausts gas to the atmosphere to relieve pressure.

[0061] The negative pressure protection and safety relief device and method for negative pressure pipeline working fluid provided by the present invention can be used for negative pressure protection at the connection position of the helium low-temperature transmission pipeline exposed to the air, and provide protection when the pipeline is overpressured.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A negative pressure pipeline working medium negative pressure protection and safety discharge device, characterized in that: include: A sealing cover, wherein both ends of the sealing cover are sealed to form a protective cavity; a ball valve, one end of which is in sealed communication with the protection cavity via a pipe, and the other end of which is in sealed communication with a vacuum generator or a helium supply device; A primary safety valve, one end of which is connected to the pipeline to be protected via a connecting pipeline, and the primary safety valve has a first trip pressure; a secondary safety valve, one end of which is connected to the protection cavity through a pipeline, and the other end of which is connected to the recovery and purification system, the secondary safety valve having a second trip pressure, which is greater than the first trip pressure; a blasting assembly, one end of which is connected to the pipeline to be protected through a pipeline, and the blasting assembly has a third tripping pressure, which is greater than the second tripping pressure; A three-way valve, wherein the first end of the three-way valve is connected to the pipeline to be protected through a pipeline, the second end is connected to the primary safety valve through a pipeline, and the third end is connected to the blasting assembly through a pipeline.

2. The negative pressure protection and safety release device for negative pressure pipeline working medium according to claim 1 is characterized in that: The sealing cover includes a cylinder, a head, a sealing cover flange and a base flange. The head is used to seal the top of the cylinder. The sealing cover is welded to the bottom of the cylinder. The base flange is fixedly connected to the sealing cover flange and is used to seal the bottom of the cylinder.

3. The negative pressure protection and safety release device for negative pressure pipeline working medium according to claim 2 is characterized in that: The base flange is also provided with a helium leak detection port, which is used to detect helium leakage in the protection cavity.

4. The negative pressure protection and safety release device for negative pressure pipeline working medium according to claim 3 is characterized in that: The first-level safety valve includes a first valve body and a first air inlet, a first exhaust port, a first valve core and a first trip controller provided on the first valve body. The first air inlet is connected to the connecting pipeline, the first exhaust port discharges helium into the protection cavity, and the first trip controller is used to control the tripping of the first valve core according to the pressure of the pipeline to be protected.

5. The negative pressure protection and safety release device for negative pressure pipeline working medium according to claim 4 is characterized in that: The secondary safety valve includes a second valve body and a second air inlet, a second exhaust port, a second valve core and a second take-off controller arranged on the second valve body. The second air inlet is connected to the protection cavity, and the second exhaust port is connected to the recovery and purification system. The second take-off controller is used to control the take-off of the first valve core according to the pressure conditions in the protection cavity.

6. The negative pressure protection and safety release device for negative pressure pipeline working medium according to claim 2, characterized in that: A sealing ring is also pressed between the base flange and the sealing cover flange.

7. A method for negative pressure protection and safe discharge of negative pressure pipeline working medium, based on the negative pressure protection and safe discharge device for negative pressure pipeline working medium according to any one of claims 1 to 6, characterized in that: Including steps: Open the ball valve, close the primary safety valve, secondary safety valve and blasting assembly; The protective cavity is vacuumed through the ball valve and stops when the vacuum reaches a set value; Filling the protection cavity with helium through the ball valve, wherein the purity of the helium is the same as that of the helium in the pipeline to be protected; When negative pressure is formed in the pipeline to be protected, the helium in the protection cavity enters the pipeline to be protected under negative pressure; When the pressure of the pipeline to be protected is greater than the first trip pressure, the first-level safety valve trips and exhausts air into the protection cavity through the first exhaust port; When the pressure in the protection cavity is greater than the second trip pressure of the secondary safety valve, exhaust is discharged to the recovery and purification system through the second exhaust port; When the primary safety valve or the secondary safety valve fails to trip in time due to a fault, the bursting disc trips when the third tripping pressure of the bursting disc is reached, and exhausts gas to the atmosphere for pressure relief.

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