A negative pressure pipeline working fluid pressure collection and negative pressure protection device and method

Abstract

The present invention relates to a negative pressure pipeline working medium pressure collection and negative pressure protection device and method, comprising: a sealing cover, the two ends of the sealing cover are sealed to form a sealed cavity; a ball valve, one end of the ball valve is connected to the sealed cavity through a pipeline, and the other end of the ball valve is connected to a vacuum generating device or a helium supply device; a vacuum electrical connector, the vacuum electrical connector is provided with a signal pin, and the vacuum electrical connector is sealed and connected to the cavity; a pressure monitoring pipeline and a pressure detection mechanism, the pressure detection mechanism is used to detect a pressure signal, the pressure detection mechanism is connected to the pin signal on the vacuum electrical connector, and the pin is used to output the pressure signal. The device and method can be used for negative pressure protection at the connection point between a helium cryogenic transmission pipeline and a pressure transmitter, and the pressure signal is transmitted to the control system.

Description

Technical Field

[0001] The present invention relates to the technical field of superfluid helium cryogenic refrigeration, and in particular to a negative pressure pipeline working fluid pressure collection and negative pressure protection device and method. Background Art

[0002] In large-scale superfluid helium cryogenic refrigeration systems, helium cryogenic transmission pipelines are responsible for transporting the cryogenic working fluid from the refrigerator to the load and recovering the cooling energy, completing a closed cycle. When the cryogenic system operates at a minimum temperature of 4.2K, the working fluid pressure in the transmission pipeline is slightly higher than atmospheric pressure. When the cryogenic system operates at 2K, the system reduces pressure and cools down to 2K saturated superfluid helium. The saturation pressure of 2K saturated superfluid helium is 3129 Pa, far below atmospheric pressure. During operation, pipeline pressure data must be sampled and monitored to ensure safe and stable operation of the entire cryogenic system.

[0003] Cryogenic fluid pressure is typically collected and controlled by running a small-diameter pipe from the cryogenic pipeline to the ambient temperature end, where it is then connected to a pressure transmitter. When the system operates at negative pressure, air can intrude into the cryogenic pipeline through the negative pressure connection of the pressure transmitter, affecting the purity of the liquid helium and severely impacting the performance of the entire cryogenic system.

[0004] For this negative pressure line, the actual operating pressure spans from normal pressure to negative pressure, requiring the selection of a suitable pressure transmitter to achieve high-precision pressure measurement over a wide range. Due to the different ranges of pressure transmitters, it is typically necessary to set up pressure transmitters that perform optimally under positive pressure (range 0-2.0 bar) and negative pressure (range 0-0.1 bar) conditions. Therefore, a negative pressure line working fluid pressure acquisition and negative pressure protection component is required to monitor and protect the negative pressure line at all operating states, ensuring the safe and stable operation of the cryogenic system. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to provide a negative pressure pipeline working fluid pressure collection and negative pressure protection device and method, which can be used for negative pressure protection at the connection point between the helium cryogenic transmission pipeline and the pressure transmitter, and transmit the pressure signal to the control system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a negative pressure pipeline working fluid pressure collection and negative pressure protection device, comprising:

[0008] A sealing cover, wherein both ends of the sealing cover are sealed to form a sealed cavity;

[0009] 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;

[0010] a vacuum electrical connector, wherein a signal pin is provided on the vacuum electrical connector and the vacuum electrical connector is in sealed communication with the cavity;

[0011] A pressure monitoring pipeline and a pressure detection mechanism, one end of the pressure monitoring pipeline is connected to the hydraulic pipeline, and the other end passes through the sealing cover and is connected to the pressure detection mechanism. The pressure detection mechanism is used to detect the pressure signal. The pressure detection mechanism is connected to the signal pin on the vacuum electrical connector, and the signal pin is used to output the pressure signal.

[0012] Furthermore, the pressure detection mechanism also includes a VCR assembly, a tee, a negative pressure transmitter and a positive pressure transmitter. One end of the pressure monitoring pipeline is connected to the infusion tube to be detected, and the other end passes through the bottom end of the sealing cover cylinder and is connected to the VCR assembly. The VCR assembly is connected to the first end of the tee, the second end of the tee is connected to the negative pressure transmitter, and the third end is connected to the positive pressure transmitter. The negative pressure transmitter and the positive pressure transmitter are respectively connected to the signal pin signal through two signal lines.

[0013] Furthermore, the sealing cover includes a cylinder, a head, a sealing cover flange and a sealing cover base. The top of the cylinder is sealed by the head, and the bottom is sealed and connected to the sealing cover base through the sealing cover flange. The sealing cover base is provided with a first through hole, a second through hole and a third through hole. The ball valve is sealed and connected to the cavity through a pipeline. The pipeline passes through the first through hole and is sealed to the first through hole. The vacuum electrical connector is sealed to the second through hole. The pressure monitoring line passes through the third through hole and is sealed to the third through hole.

[0014] Furthermore, the vacuum connector and the second through hole are sealed by a flange connection tube and a vacuum electrical connector flange, the top of the flange connection tube is welded to the second through hole, the vacuum electrical connector flange is connected to the bottom of the flange connection tube, and the pipeline and pressure detection pipeline are welded to the first through hole and the third through hole respectively.

[0015] Furthermore, a sealing ring is provided between the vacuum electrical connector and the vacuum electrical connector flange.

[0016] Furthermore, a helium leak detection port is provided on the flange base for detecting the vacuum state in the cavity.

[0017] Furthermore, the measurement ranges of the positive pressure transmitter and the negative pressure transmitter are different.

[0018] Another aspect of the present invention further provides a method for collecting working fluid pressure in a negative pressure pipeline and for negative pressure protection, comprising the steps of:

[0019] Connect the negative pressure pipeline working medium pressure collection and negative pressure protection device to the infusion pipeline;

[0020] Open the ball valve to evacuate the protective chamber, and stop evacuating after a period of time;

[0021] Helium with the same purity as that in the infusion pipeline is filled into the cavity through the ball valve so that the pressure of the helium in the cavity is slightly greater than the atmospheric pressure;

[0022] The pressure of the infusion pipeline is collected by the negative pressure transmitter and the positive pressure transmitter, and the collected analog signal is transmitted to the control system through the signal line and the pin. When the infusion pipeline is running at positive pressure, the air cannot contaminate the helium in the protection cavity. When negative pressure is formed in the pipeline, the helium in the protection cavity replaces the air and leaks into the negative pressure pipeline, avoiding contamination caused by air inhalation.

[0023] Furthermore, the pressure measuring ranges of the negative pressure transmitter and the positive pressure transmitter are different;

[0024] The pressure of the infusion pipeline is collected by the negative pressure transmitter and the positive pressure transmitter, and the collected analog signal is transmitted to the control system through the signal line and the pin. Specifically:

[0025] When the current output of the positive pressure transmitter and the negative pressure transmitter is less than the set value, both the negative pressure transmitter and the positive pressure transmitter are within the range, the system is in the negative pressure operation state, the measurement accuracy of the negative pressure transmitter is higher, and the measurement result of the negative pressure transmitter is adopted;

[0026] When the output current of the negative pressure transmitter is greater than the set value, the negative pressure transmitter has exceeded the range. At this time, the system is in an operating pressure higher than the range of the negative pressure transmitter, and the measurement result of the positive pressure transmitter is adopted.

[0027] Furthermore, the steps include:

[0028] The vacuum state in the cavity is detected through a helium detection port.

[0029] The present invention has the following advantages due to the adoption of the above technical solution:

[0030] The negative pressure pipeline working fluid pressure acquisition and negative pressure protection device provided by the present invention can be used to protect the threaded connection between the pressure transmitter and the monitoring pipeline, and can lead the monitoring signal to the atmosphere without destroying the negative pressure protection environment. The ball valve supplies helium (99.999%) of the same purity as that in the system into the sealing cover cylinder of the negative pressure pipeline working fluid negative pressure protection and safety relief assembly. When the pipeline is operating at 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 of the helium circulation environment in the pipeline is effectively avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] In the attached figure:

[0033] Figure 1 It is a structural diagram of the negative pressure pipeline working medium pressure collection and negative pressure protection device;

[0034] Figure 2 It is a structural diagram of the negative pressure pipeline working medium pressure collection and negative pressure protection device without the sealing cover;

[0035] Figure 3 1. It is a structural diagram of the sealing cover base;

[0036] Figure 4 It is a schematic diagram of the structure of a vacuum electrical connector;

[0037] The symbols in the accompanying drawings represent the following:

[0038] 1-Pressure monitoring pipeline; 2-Protective enclosure; 3-Ball valve; 4-Air supply pipe interface; 5-Base flange; 6-First sealing ring; 7-Sealing cover flange; 8-Cylinder; 9-Head; 10-Flange connecting cylinder; 11-Vacuum electrical connector flange; 12-Second sealing ring; 13-Vacuum electrical connector; 15-VCR assembly; 16-Tee; 17-Second end; 18-Negative pressure transmitter; 19-Positive pressure transmitter; 20-Third end; 21-Mounting hole; 22-Flange screw hole; 23-First through hole; 24-Third through hole; 25-First helium leak detection port; 26-Second through hole; 27-Flange screw hole; 28-Signal pin; 29-Second helium leak detection port. DETAILED DESCRIPTION

[0039] 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.

[0040] The embodiments of the present invention address the problem that when existing negative pressure collection devices operate at negative pressure, air will intrude into the cryogenic pipeline through the negative pressure connection components of the pressure transmitter, affecting the purity of the liquid helium and thus seriously affecting the working performance of the entire cryogenic system. A negative pressure pipeline working medium pressure collection and negative pressure protection device and method are provided. The device and method can, when the pipeline operates at negative pressure, allow the helium in the sealing cover cylinder to be sucked into the cryogenic transmission pipeline through the safety valve connection thread. Since the amount of helium sucked in is very 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.

[0041] Example 1

[0042] like Figures 1 to 4 As shown, the negative pressure pipeline working fluid pressure collection and negative pressure protection device includes a sealing cover 8, a ball valve 3, a vacuum electrical connector 13, a pressure monitoring pipeline 1 and a pressure detection mechanism. The two ends of the sealing cover 8 are sealed to form a sealed cavity. One end of the ball valve 3 is sealed and connected to the sealed cavity through a pipeline, and the other end of the ball valve 3 is connected to a vacuum generating device (not shown in the figure) or a helium providing device (not shown in the figure). A signal pin 28 is provided on the vacuum electrical connector 13, and the vacuum electrical connector 28 is sealed and connected to the cavity. One end of the pressure monitoring pipeline 1 is connected to the infusion pipeline, and the other end is connected to the pressure detection mechanism through the sealing cover 8. The pressure detection mechanism is used to detect the pressure signal. The pressure detection mechanism is newly connected to the signal pin 28 on the vacuum electrical connector 13, and the signal pin 28 is used to output the pressure signal.

[0043] To perform pressure signal detection, the pressure monitoring line 1 is sealed and connected to the infusion line. The manual switch of ball valve 3 is open. A vacuum pump connected to the pressure monitoring line 1 is used to evacuate the protective chamber. When the vacuum reaches the desired level, the vacuum pump valve is closed. The manual switch of ball valve 3 is kept open, and helium (99.999%) of the same purity as that in the line is filled into the protective chamber through the inlet ball valve 3, at a pressure slightly above the local atmospheric pressure. This cycle is repeated three times to ensure the purity of the helium in the protective chamber. The pressure monitoring line 1 and the infusion line are connected in parallel, maintaining the same pressure. The pressure in the infusion line is transmitted to the pressure detection mechanism through the pressure monitoring line 1. When the infusion line operates at positive pressure, air cannot contaminate the helium in the protective chamber. When the infusion line is under negative pressure, the protective chamber is filled with helium of the same purity as that in the line. This helium replaces air and leaks into the negative pressure line, effectively preventing contamination caused by air inhalation.

[0044] Furthermore, in order to ensure the accuracy of detection under different working pressures, the pressure detection mechanism also includes a VCR component 15, a tee 16, a negative pressure pressure transmitter 18 and a positive pressure pressure transmitter 19. One end of the pressure monitoring pipeline 1 is connected to the infusion tube to be detected, and the other end passes through the bottom end of the sealing cover cylinder 8 and is connected to the VCR component 15. The VCR component 15 is connected to the first end of the tee 16, the second end 17 of the tee 16 is connected to the negative pressure pressure transmitter 18, and the third end 20 is connected to the positive pressure pressure transmitter 19. The negative pressure pressure transmitter 18 and the positive pressure pressure transmitter 19 are respectively connected to the signal pin 28 through two signal lines, and the measurement range of the negative pressure pressure transmitter 18 and the positive pressure pressure transmitter 19 is not passed.

[0045] The two pressure transmitters have different measurement ranges, ensuring measurement accuracy under different working pressures. A vacuum electrical connector 13 is used to draw out the current signal, and the signal lines drawn from the positive pressure transmitter 19 and the negative pressure transmitter 18 are welded to the vacuum electrical connector 13, so that the analog signal can be finally drawn out to the control system. When the current output of the positive pressure transmitter 19 and the negative pressure transmitter 18 is less than 20mA, both types of pressure transmitters are within their range. At this time, it indicates that the system is in a negative pressure operating state, and the measurement accuracy of the negative pressure transmitter 18 is higher. At this time, the measurement result of the negative pressure transmitter 18 is adopted; when the output current of the negative pressure transmitter 18 is greater than 20mA, the negative pressure transmitter 32 has exceeded its range. At this time, it indicates that the system is in an operating pressure higher than the range of the negative pressure transmitter 19. At this time, the measurement result of the positive pressure transmitter 19 is adopted.

[0046] Furthermore, in order to improve the sealing reliability and prevent air from contaminating the helium in the infusion pipeline, the sealing cover 8 includes a cylinder, a head 9, a sealing cover flange 7 and a sealing cover base 5. The top of the cylinder is sealed by the head 9, and the bottom is sealed and connected to the sealing cover base 5 through the sealing cover flange 7. The sealing cover base 5 is provided with a first through hole 23, a second through hole 26 and a third through hole 24. The ball valve 3 is connected to the cavity through a pipeline seal. The pipeline passes through the first through hole 23 and is sealed with the first through hole. The vacuum electrical connector 13 is sealed with the second through hole 26. The pressure monitoring line 1 passes through the third through hole 24 and is sealed with the third through hole 24.

[0047] The sealing cover base 5 is connected to the sealing cover flange 7 by bolts, and screw holes 22 are provided on the sealing cover base.

[0048] Furthermore, the vacuum connector 13 and the second through hole 26 are sealed together via the flange connection tube 10 and the vacuum electrical connector flange 11. The top of the flange connection tube 10 is welded to the second through hole 26, and the vacuum electrical connector flange 11 is connected to the bottom of the flange connection tube 10. The pipeline and pressure monitoring line 1 are respectively welded to the first through hole 23 and the third through hole 24. The vacuum electrical connector 13 and the vacuum electrical connector flange 11 are connected by bolts, and the vacuum electrical connector 13 is provided with screw holes 27.

[0049] In order to improve the sealing reliability of the connection between the vacuum connector 13 and the vacuum connector flange 11 , a sealing ring 12 is further provided between the vacuum electrical connector 13 and the vacuum electrical connector flange 11 .

[0050] The flange base 5 and the vacuum electrical connector are further provided with a first helium leak detection port 25 and a second helium leak detection port 29 for detecting the vacuum state in the cavity.

[0051] The outer side of the pressure monitoring pipeline 1 is also provided with a protective casing 2 for protecting the monitoring pipeline. The top end of the protective casing is sealed and fixedly connected to the base flange.

[0052] Example 2

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

[0054] S1. Connect the negative pressure pipeline working medium pressure collection and negative pressure protection device described in Example 1 to the infusion pipeline;

[0055] S2, open the ball valve 3, evacuate the protective chamber, stop evacuating when the vacuum reaches a preset value, and perform a leak test on the vacuum state through the first helium leak detection port 25 and the second helium leak detection port 29;

[0056] S3. Fill the cavity with helium of the same purity as that in the infusion pipeline through the ball valve 3, so that the pressure of the helium in the cavity is slightly greater than the atmospheric pressure. Repeat this cycle three times to ensure the purity of the helium in the protection cavity.

[0057] The pressure monitoring circuit is connected in parallel with the infusion line, and both maintain the same pressure. The pressure within the infusion line is transmitted through the protected line outlet tube 1 to a negative pressure transmitter 18 and a positive pressure transmitter 19. The two pressure transmitters have different measurement ranges, ensuring measurement accuracy at different operating pressures. When the infusion line operates at positive pressure, air cannot contaminate the helium in the cavity. When negative pressure forms within the pipeline, the protective cavity is filled with helium of the same purity as the pipeline. This helium replaces air and leaks into the negative pressure line, effectively preventing contamination caused by air inhalation.

[0058] S4. Use the vacuum electrical connector 13 to draw out the current signal. By welding the signal lines drawn from the positive pressure transmitter 19 and the negative pressure transmitter 18 to the vacuum electrical connector 13, the analog signal can finally be drawn out to the control system. When the current output of the positive pressure transmitter 19 and the negative pressure transmitter 18 is less than 20mA, both types of pressure transmitters are within their range. At this time, it indicates that the system is in a negative pressure operating state, and the measurement accuracy of the negative pressure transmitter 18 is higher. In this case, the measurement result of the negative pressure transmitter 18 is adopted. When the output current of the negative pressure transmitter 18 is greater than 20mA, the negative pressure transmitter 18 has exceeded its range. At this time, it indicates that the system is in an operating pressure higher than the range of the negative pressure transmitter. In this case, the measurement result of the positive pressure transmitter 19 is adopted.

[0059] The installation method of the above-mentioned negative pressure pipeline working fluid pressure collection and negative pressure protection components is simple and easy to operate. Through connection methods such as ferrules and flanges, the installation of the negative pressure pipeline working fluid pressure collection and negative pressure protection components is realized, and disassembly and replacement are very convenient.

[0060] 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 pressure collection and negative pressure protection device, characterized in that: include: A sealing cover, wherein both ends of the sealing cover are sealed to form a sealed 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 sealed communication with a vacuum generator or a helium supply device; a vacuum electrical connector, wherein a signal pin is provided on the vacuum electrical connector and the vacuum electrical connector is in sealed communication with the cavity; a pressure monitoring line and a pressure detection mechanism, wherein one end of the pressure monitoring line is connected to the hydraulic line, and the other end passes through the sealing cover and is connected to the pressure detection mechanism, the pressure detection mechanism is used to detect a pressure signal, the pressure detection mechanism is connected to a signal pin on the vacuum electrical connector, and the signal pin is used to output the pressure signal; The pressure detection mechanism also includes a VCR assembly, a tee, a negative pressure transmitter and a positive pressure transmitter. One end of the pressure monitoring pipeline is connected to the infusion tube to be detected, and the other end passes through the bottom end of the sealing cover cylinder and is connected to the VCR assembly. The VCR assembly is connected to the first end of the tee, the second end of the tee is connected to the negative pressure transmitter, and the third end is connected to the positive pressure transmitter. The negative pressure transmitter and the positive pressure transmitter are respectively connected to the signal pin signal through two signal lines; The sealing cover includes a cylinder, a head, a sealing cover flange and a sealing cover base. The top of the cylinder is sealed by the head, and the bottom is sealed and connected to the sealing cover base through the sealing cover flange. The sealing cover base is provided with a first through hole, a second through hole and a third through hole. The ball valve is connected to the cavity through a pipeline seal. The pipeline passes through the first through hole and is sealed to the first through hole. The vacuum electrical connector is sealed to the second through hole. The pressure monitoring line passes through the third through hole and is sealed to the third through hole.

2. The negative pressure pipeline working medium pressure collection and negative pressure protection device according to claim 1 is characterized in that: The vacuum connector and the second through hole are sealed by a flange connection tube and a vacuum electrical connector flange. The top of the flange connection tube is welded to the second through hole. The vacuum electrical connector flange is connected to the bottom of the flange connection tube. The pipeline and the pressure detection pipeline are welded to the first through hole and the third through hole respectively.

3. The negative pressure pipeline working medium pressure collection and negative pressure protection device according to claim 1 is characterized in that: A sealing ring is further provided between the vacuum electrical connector and the vacuum electrical connector flange.

4. The negative pressure pipeline working medium pressure collection and negative pressure protection device according to claim 1 is characterized in that: The sealing cover base is also provided with a helium leak detection port for detecting the vacuum state in the cavity.

5. The negative pressure pipeline working medium pressure collection and negative pressure protection device according to claim 1 is characterized in that: The positive pressure transmitter connection and the negative pressure transmitter have different measuring ranges.

6. A method for collecting working medium pressure in a negative pressure pipeline and for negative pressure protection, characterized in that: Including steps: Connecting the negative pressure pipeline working medium pressure collection and negative pressure protection device according to any one of claims 1 to 5 to the infusion pipeline; Open the ball valve to evacuate the protective chamber, and stop evacuating after a period of time; Helium with the same purity as that in the infusion pipeline is filled into the cavity through the ball valve so that the pressure of the helium in the cavity is slightly greater than the atmospheric pressure; The pressure of the infusion pipeline is collected by the negative pressure transmitter and the positive pressure transmitter, and the collected analog signal is transmitted to the control system through the signal line and the pin. When the infusion pipeline is running at positive pressure, the air cannot contaminate the helium in the protection cavity. When negative pressure is formed in the pipeline, the helium in the protection cavity replaces the air and leaks into the negative pressure pipeline, avoiding contamination caused by air inhalation.

7. The method for collecting working medium pressure in a negative pressure pipeline and protecting negative pressure according to claim 6, characterized in that: The pressure measuring ranges of the negative pressure transmitter and the positive pressure transmitter are different; The pressure of the infusion line is collected by the negative pressure transmitter and the positive pressure transmitter, and the collected analog signal is transmitted to the control system through the signal line and the pin. Specifically: When the current output of the positive pressure transmitter and the negative pressure transmitter is less than the set value, both the negative pressure transmitter and the positive pressure transmitter are within the range, the system is in the negative pressure operation state, the measurement accuracy of the negative pressure transmitter is higher, and the measurement result of the negative pressure transmitter is adopted; When the output current of the negative pressure transmitter is greater than the set value, the negative pressure transmitter has exceeded the range. At this time, the system is in an operating pressure higher than the range of the negative pressure transmitter, and the measurement result of the positive pressure transmitter is adopted.

8. The method for collecting working medium pressure in a negative pressure pipeline and protecting negative pressure according to claim 6, characterized in that: Also includes the steps: The vacuum state in the cavity is detected through a helium detection port.

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