Liquid nitrogen temperature zone friction and air tightness device

Abstract

The application discloses a device for measuring friction and air tightness in a liquid nitrogen temperature zone, which comprises a connecting rod, a bellows, an upper cover and a lower cylinder, the bellows is sleeved on the upper part of the connecting rod, the upper cover is connected to the middle part of the connecting rod, a differential pressure disc is connected to the lower part of the connecting rod, a guide disc is connected to the end of the connecting rod, the upper cover and the lower cylinder are fastened by bolts, the guide disc is arranged between the upper cover and the lower cylinder, and the upper cover and the lower cylinder are respectively provided with a pipe joint.The device can easily replace the differential pressure disc, can measure the friction and air tightness of a damping ring in the liquid nitrogen temperature zone, and can ensure that the force value is not affected by external factors when the friction is measured.

Description

Technical Field

[0001] This invention belongs to the field of equipment manufacturing technology and relates to a device for measuring friction and airtightness in liquid nitrogen temperature range. Background Technology

[0002] Currently, more and more valves used in new-generation launch vehicles are cryogenic valves, operating at temperatures ranging from -253℃ to -196℃. Testing individual components in the liquid nitrogen temperature range requires immersing the valves in liquid nitrogen. With the continuous development of science and technology, the specifications for individual components are becoming increasingly stringent, and the required testing equipment must also offer higher testing efficiency while meeting these requirements.

[0003] In liquid nitrogen temperature zone valves, there is a structure where a damping ring is placed at the guide position between the differential pressure disc and the guide disc. This damping ring provides friction and a seal. In a liquid nitrogen environment, this product has certain requirements for the friction and airtightness of this part. When measuring friction, a connecting rod is needed to move the differential pressure disc. Maintaining the liquid nitrogen temperature zone requires immersing the device in liquid nitrogen. After immersion, problems arise when measuring friction: when the differential pressure disc moves, the damping ring position must be kept in a helium environment and cannot come into contact with air. If it does, the damping ring position will freeze, affecting the friction value. Simultaneously, the airtightness of the damping ring position needs to be measured, requiring assurance that there are no leaks in other parts of the device. Existing devices have poor sealing in moving parts, which can cause air to be drawn back into the device, freezing at the damping ring position in a low-temperature environment, causing jamming or distorted force values. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device for measuring friction and airtightness in the liquid nitrogen temperature range.

[0005] To achieve the above objectives, the present invention employs the following technical solutions:

[0006] A device for measuring friction and airtightness in liquid nitrogen temperature range includes a connecting rod, a bellows, an upper cover, and a lower cylinder. The bellows is fitted onto the upper part of the connecting rod, the upper cover is connected to the middle part of the connecting rod, a differential pressure plate is connected to the lower part of the connecting rod, and a guide plate is connected to the end of the connecting rod. The upper cover and the lower cylinder are tightened together by bolts, and the guide plate is located between the upper cover and the lower cylinder. The upper cover and the lower cylinder are respectively provided with connectors.

[0007] As a preferred embodiment, the lower part of the connecting rod and the inner hole of the differential pressure plate are respectively provided with steps. The steps cooperate with the gasket to ensure that the connecting rod is sealed in the radial direction. When the connecting rod moves, it drives the differential pressure plate.

[0008] As a preferred embodiment, the lower end of the differential pressure plate is provided with a guide shaft to prevent misalignment during movement.

[0009] As a preferred embodiment, a gasket is provided at the connection between the lower cylinder and the guide plate to provide a sealing function.

[0010] As a preferred embodiment, the guide plate is provided with a guide hole, through which the connecting rod passes.

[0011] As a preferred embodiment, the corrugated pipe is a flexible corrugated pipe.

[0012] The present invention has the following advantages:

[0013] This invention enables easy replacement of the differential pressure plate and allows for the measurement of damping ring friction and airtightness at liquid nitrogen temperatures, while ensuring that the force value is not affected by external factors during friction measurement. If the component dimensions change, only the diameters of the guide plate and differential pressure plate need to be adjusted. The bellows compression provides a sealing effect, enabling the measurement of damping ring friction at liquid nitrogen temperatures.

[0014] Since many valve products incorporate this damping ring structure, when the friction value decreases, it is only necessary to change the push mechanism to a pull mechanism and subtract the weight of the rod and differential pressure plate. This invention has significant effects and implications in ensuring production quality, improving production efficiency, and reducing production costs, and possesses long-term promotional value. Attached Figure Description

[0015] Figure 1 A schematic diagram of the structure of this invention.

[0016] In the diagram: 1. Connecting rod, 2. Bellows, 3. Differential pressure plate, 4. Gasket, 5. Top cover, 6. Connecting nozzle, 7. Guide plate, 8. Lower cylinder, 9. Damping ring. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings.

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Example:

[0020] A device for measuring friction and airtightness in liquid nitrogen temperature zones includes a connecting rod, a bellows, an upper cover, and a lower cylinder. The bellows is fitted onto the upper part of the connecting rod, the upper cover is connected to the middle of the connecting rod, a differential pressure plate is connected to the lower part of the connecting rod, and a guide plate is connected to the end of the connecting rod. The upper cover and the lower cylinder are tightened together by bolts. The guide plate is located between the upper cover and the lower cylinder. The upper cover and the lower cylinder are each provided with a connector nozzle. The lower part of the connecting rod and the inner hole of the differential pressure plate are respectively provided with steps. The steps cooperate with gaskets to ensure a seal in the radial direction of the connecting rod. When the connecting rod moves, it drives the differential pressure plate.

[0021] The differential pressure disc has a guide shaft at its lower end to prevent misalignment during movement. A gasket is provided at the connection between the lower cylinder and the guide disc for sealing. The guide disc has a guide hole through which the connecting rod passes. The bellows is a flexible bellows.

[0022] The workflow of this embodiment is as follows:

[0023] 1. First, the upper end of the flexible bellows needs to be welded to the upper end of the connecting rod, and the lower end of the bellows needs to be welded to the upper cover. This ensures that the connecting rod can be stretched and contracted through the bellows.

[0024] 2. Add a shim to the step position of the differential pressure plate, place the differential pressure plate on the connecting rod, and tighten the lower end with a nut.

[0025] 3. Place washers into the upper and lower grooves of the guide plate, and then place the guide plate in the lower cylinder.

[0026] 4. Place the top cover above the guide plate and tighten the top cover to the lower cylinder with bolts.

[0027] 5. Replace the upper and lower chambers of the device through the nozzles. Fill the lower cylinder with 0.1MPa helium through the right nozzle and open the lower cylinder with the left nozzle. Fill the upper cover with 0.1MPa helium through the right nozzle and open the left nozzle. Use helium as the replacement gas at a pressure of 0.1MPa to ensure that there is no pressure difference between the upper and lower chambers.

[0028] 6. After the replacement is completed, place the device in liquid nitrogen. When it is necessary to measure the friction force, pull the differential pressure plate to the upper limit position, close the left connecting nozzle of the upper cover and the lower cylinder, and use the friction force machine to push the upper end of the connecting rod downward. At this time, the friction force at the damping ring can be read.

[0029] 7. When it is necessary to measure the air tightness, vent the right connector of the lower cylinder and close the left connector of the lower cylinder. Measure the air tightness with the right connector of the upper cover and close the left connector of the upper cover. The leakage rate at this time is the leakage rate at the damping ring position.

[0030] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A device for measuring friction and airtightness in a liquid nitrogen temperature range, characterized in that, It includes a connecting rod, a bellows, an upper cover, and a lower cylinder. The bellows is fitted onto the upper part of the connecting rod. The upper cover is connected to the middle part of the connecting rod. A differential pressure plate is connected to the lower part of the connecting rod. A guide plate is connected to the end of the connecting rod. The upper cover and the lower cylinder are tightened together by bolts. The guide plate is located between the upper cover and the lower cylinder. The upper cover and the lower cylinder are respectively provided with pipe nozzles.

2. The device for measuring friction and airtightness in liquid nitrogen temperature range according to claim 1, characterized in that: The lower part of the connecting rod and the inner hole of the differential pressure plate are respectively provided with steps. The steps cooperate with the gaskets, and the differential pressure plate is driven when the connecting rod moves.

3. The device for measuring friction and airtightness in liquid nitrogen temperature range according to claim 1, characterized in that: The differential pressure plate is equipped with a guide shaft at its lower end.

4. The device for measuring friction and airtightness in liquid nitrogen temperature range according to claim 1, characterized in that: A gasket is provided at the connection between the lower cylinder and the guide plate.

5. The device for measuring friction and airtightness in liquid nitrogen temperature range according to claim 1, characterized in that: The guide plate is provided with a guide hole, through which the connecting rod passes.

6. The device for measuring friction and airtightness in liquid nitrogen temperature range according to claim 1, characterized in that: The corrugated pipe is a flexible corrugated pipe.

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