Stainless steel inner container strain strengthening system

Abstract

The utility model relates to the field of manufacturing of cryogenic pressure containers, in particular to a strain strengthening system for a stainless steel inner container. Comprising an inner container supporting tool, a stainless steel inner container is placed on the inner container supporting tool, a displacement sensor, a pressure gauge and a connecting pipeline are arranged on the stainless steel inner container, the connecting pipeline is connected with a hydraulic press, the hydraulic press is connected with a pressure medium source, and a pressure transmitter and a safety device are arranged on the hydraulic press. And the pressure transmitter, the safety device, the displacement sensor and the pressure gauge are connected with a strain strengthening automatic control system. The technical scheme has the beneficial effects that the durability of equipment is enhanced, the yield strength of a material can be improved, the inner container of the cryogenic pressure container is thinned and safe, and the allowable stress of a stainless steel plate is effectively improved. And the application of the automatic control system can find abnormal conditions in time, so that accidents caused by overlarge pressure or overlarge displacement are avoided, and the operation safety is improved.

Description

Technical Field

[0001] The utility model relates to the field of cryogenic pressure vessel manufacturing, in particular to a stainless steel inner vessel strain strengthening system. Background Art

[0002] Cryogenic pressure vessels are composed of inner containers and outer shells. The inner containers contain refrigerated liquefied gases, such as liquid oxygen, liquid nitrogen, liquid argon, LNG, etc. The interlayer between the inner container and the outer shell is evacuated and filled or wrapped with insulating materials to reduce heat transfer and radiant heat, so as to achieve the purpose of keeping the refrigerated liquefied gas cold and storing it. Various refrigerated liquefied gases have low temperatures. The inner containers are usually welded from austenitic stainless steel, which has good performance even at low temperatures, and the outer shells are mostly made of carbon steel and low alloy steel. Our company hopes to develop a stainless steel inner container (≤10m3) strain strengthening system to make the inner container of the cryogenic pressure vessel thinner and safer, that is, to effectively increase the allowable stress of the stainless steel plate, save materials, and improve the market competitiveness of enterprises. Utility Model Content

[0003] The technical problem to be solved by this technical solution is: even if the inner container of the cryogenic pressure vessel is made thinner, it is safe and can effectively increase the allowable stress of the inner container steel plate and increase the yield strength of the inner container.

[0004] To achieve the above purpose, the utility model creates a technical solution: a stainless steel container strain hardening system, including a container support tooling, a stainless steel container is placed on the container support tooling, a displacement sensor, a pressure gauge and a connecting pipeline are provided on the stainless steel container, a pressure gauge and a valve are provided on the connecting pipeline, the connecting pipeline is connected to a hydraulic press, the hydraulic press is connected to a pressure medium source, a pressure transmitter and a safety device are provided on the hydraulic press, and the pressure transmitter, the safety device, the displacement sensor and the pressure gauge are connected to a strain hardening automatic control system. The strain hardening automatic control system includes a measurement module, a time module, a pressure signal module, a displacement data module, and a hydraulic press control module. The measurement module can record the change in the cross-sectional circumference of the stainless steel container, the time module records the pressure and displacement data of the pressure signal module and the displacement data module at intervals, and the hydraulic press control module automatically controls the pressure change and pressure increase rate during strain hardening, maintains the set pressure, and maintains the pressure at the set pressure stop point.

[0005] Furthermore, the pressure signal module can convert the pressure of the pressure sensor into the internal pressure value of the inner container, and the displacement data module can convert the signal of the displacement sensor into the variable length value of the circumference of the inner container. The beneficial effect of this design is that the pressure signal module and the displacement data module are directly connected to the pressure sensor and the displacement sensor, and the signals generated by them are converted and used to calculate the pressure value and displacement value in the inner container respectively. This method can minimize the errors that may occur in the intermediate links and improve the accuracy and reliability of the system.

[0006] Furthermore, the surface of the container support tooling is arc-shaped, and the surface layer of the container support tooling is provided with a buffer pad to provide a more stable environment for the container changes. This design can effectively absorb and disperse vibrations to reduce vibration collisions and impacts of the container during the stress change process.

[0007] Furthermore, the strain hardening automatic control system is also provided with a data output module, which automatically records relevant data. The data output module is an important component of the strain hardening automatic control system. It is mainly responsible for processing and recording various data collected by the system, and outputting the results to users or other devices in an appropriate manner.

[0008] The beneficial effects of the improved technical solution are:

[0009] a) High precision and stability: The system uses pressure transmitters and time modules to monitor pressure changes in real time, ensuring the accuracy of the measurement. At the same time, through the synergy of the displacement data module and the hydraulic press control module, the stress of the stainless steel container is precisely controlled, ensuring the efficient operation of the system.

[0010] b) Adaptability: The strain hardening automatic control system automatically adjusts the pressure of the hydraulic press according to the actual working state of the stainless steel container, so that the internal stress is always in the optimal state. This makes the system highly adaptive and can maintain stable performance output regardless of changes in the external environment.

[0011] c) Safety: The pressure transmitter and safety device in the system can monitor the pressure changes of the stainless steel container in real time. Once an abnormal situation is detected, the system will immediately activate the safety protection mechanism to ensure the safety of equipment and personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the system structure diagram of the utility model

[0013] Figure 2 This is a diagram of the inner container support tooling of the present utility model.

[0014] Figure 3 This is a diagram of the strain hardening automatic control system of the utility model.

[0015] Figure 4 This is the strain hardening principle diagram of the utility model. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solution of the utility model, the utility model is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the protection scope of the utility model.

[0017] The stainless steel container strain hardening system proposed in this utility model is mainly for containers made of austenitic stainless steel. Since austenitic stainless steel has no obvious yield stage, this characteristic of austenitic stainless steel is utilized. In this technical solution, 0.2% or 1.0% non-proportional extension strength is taken as the yield strength. Figure 4 As shown, when a tensile stress Rk greater than Rp0.2 is applied to austenitic stainless steel, after the tensile stress is unloaded, the material will produce permanent plastic deformation. When loaded again, the material will maintain elasticity along the unloading curve until the stress increases to a certain extent again and re-enters plastic deformation. The stainless steel container strain hardening system proposed in the utility model utilizes this property of austenitic stainless steel. According to GB / T18442.7-2017 "Fixed Vacuum Insulated Cryogenic Pressure Vessels Part 7: Technical Regulations for Strain Hardening of Containers", the system and corresponding tooling are designed at nearly twice the conventional Rp0.2 value. The final calculated thickness is only half of the conventional design, which greatly saves materials and improves the yield strength of the material.

[0018] The invention discloses a stainless steel container strain hardening system, comprising a container support fixture (1), on which a stainless steel container (2) is placed. Because the support of the container does not allow for constraints that limit the hardening deformation of the container, the surface of the container support fixture is arc-shaped. The surface layer of the container support fixture is provided with a buffer pad (12) to provide a more stable environment for the container change. The design can effectively absorb and disperse vibration to reduce vibration collision and impact of the container during the stress change process.

[0019] A displacement sensor (3), a pressure gauge (4) and a connecting pipeline (5) are provided on the stainless steel inner container. A plurality of displacement sensors (3) are evenly distributed on the inner container to measure the perimeter and deformation rate of the maximum deformation section of each section of the inner container. A pressure gauge (6) and a valve (7) are provided on the connecting pipeline. During the strengthening process, the pressure is displayed on the pressure gauge on the inner container. The connecting pipeline is connected to a hydraulic press (8). The pressure gauge on the connecting pipeline displays the pressure on the hydraulic press. The hydraulic press provides controllable pressure during the strengthening process. The hydraulic press is connected to a pressure medium source (9). The pressure medium source in this solution is clean water. A pressure transmitter (10) and a safety device (11) are provided on the hydraulic press to stop and alarm in case of abnormal pressure. The pressure transmitter detects and transmits the pressure signal during the strengthening process. The pressure transmitter, the safety device, the displacement sensor and the pressure gauge are connected to a strain strengthening automatic control system (20).

[0020] The strain hardening automatic control system includes a measuring module, a time module, a pressure signal module, a displacement data module, and a hydraulic press control module. The measuring module can record the change in the cross-sectional circumference of the stainless steel container. The time module records the pressure and displacement data of the pressure signal module and the displacement data module at intervals. The pressure signal module and the displacement data module are directly connected to the pressure sensor and the displacement sensor. After converting the signals they generate, they are used to calculate the pressure value and displacement value in the container respectively. The pressure signal module can convert the pressure of the pressure sensor into the pressure value inside the container. The displacement data module can convert the signal of the displacement sensor into the lengthening value of the circumference of the container. The hydraulic press control module automatically controls the change in pressure and the pressure increase rate during strain hardening, maintains the set pressure, and maintains the pressure according to the set pressure stop point.

[0021] In this scheme, the hydraulic press control module controls the pressure increase rate during strain hardening, and the maximum pressure increase rate does not exceed 0.5MPa / min; when it reaches the design pressure, the pressure increase rate does not exceed 0.1MPa / min. After the pressure rises to the hardening pressure, the pressure is maintained. During the pressure maintenance process, the circumference of the section that may produce the maximum deformation is repeatedly measured every 5 minutes, and the circumference change rate is calculated. When the pressure maintenance time is not less than 1h and the maximum circumference change rate in the last 30 minutes does not exceed 0.1% / h, the pressure maintenance is terminated and the pressure reduction begins.

[0022] The strain hardening automatic control system also has a data output module, which is an important part of the strain hardening automatic control system. It is mainly responsible for processing and recording various data collected by the system, and outputting the results to users or other devices in an appropriate manner. At the same time, the data output module can regularly back up the data collected by the system to ensure the security and integrity of the data and avoid data loss due to hardware failure and other reasons.

[0023] The working strengthening process sequence of the stainless steel inner container strain strengthening system proposed by the utility model is as follows:

[0024] Place the inner container on the inner container support fixture. Place the displacement sensor on the inner container, connect the pipeline, valve, pressure gauge, etc., and then fill the inner container with clean water.

[0025] Set the strengthening pressure on the strain hardening automatic control system, check the equipment, container and connecting pipelines, then start, raise the pressure to the design pressure, check the appearance of the container, and continue to increase the pressure to the strengthening pressure and maintain the pressure after passing the inspection. When the conditions are met, stop maintaining the pressure and start reducing the pressure. Finally, the strengthening is completed, the container is purged, and the strain hardening automatic control system reviews the strengthening data and generates a strengthening report.

[0026] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation method of the utility model. The above examples are only used to help understand the method and core idea of ​​the utility model. The above is only a preferred implementation method of the utility model. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principle of the utility model, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without improvement, should be regarded as the scope of protection of the utility model.

Claims

1. Stainless steel container strain hardening system, characterized by: It comprises a container supporting tooling, a stainless steel container is placed on the container supporting tooling, a displacement sensor, a pressure gauge and connecting pipelines are arranged on the stainless steel container, the connecting pipelines are connected to a hydraulic press, the hydraulic press is connected to a pressure medium source, a pressure transmitter and a safety device are arranged on the hydraulic press, and the pressure transmitter, the safety device, the displacement sensor and the pressure gauge are connected to a strain hardening automatic control system.

2. The stainless steel inner container strain hardening system according to claim 1, characterized in that: The strain hardening automatic control system includes a measurement module, a time module, a pressure signal module, a displacement data module, and a hydraulic press control module. The measurement module can record the change in the cross-sectional circumference of the stainless steel container, the time module records the pressure and displacement data of the pressure signal module and the displacement data module at intervals, and the hydraulic press control module automatically controls the pressure change and pressure increase rate during strain hardening, maintains the set pressure, and maintains the pressure at the set pressure stop point.

3. The stainless steel inner container strain hardening system according to claim 2, characterized in that: The pressure signal module can convert the pressure of the pressure sensor into the internal pressure value of the inner container, and the displacement data module can convert the signal of the displacement sensor into the variable length value of the circumference of the inner container.

4. The stainless steel inner container strain hardening system according to claim 1, characterized in that: The surface of the inner container supporting tooling is arc-shaped, and a buffer pad is provided on the surface layer of the inner container supporting tooling.

5. The stainless steel inner container strain hardening system according to claim 1, characterized in that: The connecting pipeline is provided with a pressure gauge and a valve.

6. The stainless steel inner container strain hardening system according to claim 1, characterized in that: The strain hardening automatic control system is also provided with a data output module, and the data output module automatically records relevant data and outputs it to the user.

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