Piping Design and Installation of Vacuum System

Vacuum systems are widely used in scientific research, industrial production, medical equipment and other fields, and the quality of its piping design and installation directly affects the performance, stability and service life of the system. In order to ensure the efficient operation of vacuum systems, designers and installers must follow a series of technical specifications and operational points. In this paper, we will discuss the key points of vacuum system piping design and installation in detail from the aspects of piping material selection, piping layout, connection, sealing technology, cleanliness control and testing and acceptance.

I. Piping material selection

The piping material of vacuum system must meet the following requirements:

1. airtightness: the material should have good airtightness to avoid gas leakage affecting the vacuum degree.

2. corrosion resistance: select corrosion-resistant materials according to the working environment, such as stainless steel, copper, aluminum and so on.

3. Mechanical strength: the material should have enough mechanical strength to withstand the pressure and vibration in system operation.

4. Thermal stability: the material should maintain stable physical and chemical properties at high or low temperatures.

5. cleanliness: the surface of the material should be smooth and easy to clean to avoid contamination of the vacuum system.

Commonly used materials include:

- Stainless steel: 316L stainless steel is the material for vacuum systems due to its excellent corrosion resistance and mechanical properties.

- Copper: Good thermal conductivity, suitable for low temperature vacuum systems.

- Aluminum: light weight, suitable for lightweight design.

Piping layout design

Piping layout design should follow the following principles:

1. short path: minimize the length of the pipe and the number of elbows to reduce gas flow resistance.

2. Avoid dead corners: piping design should avoid dead corners to prevent gas residue or pollutant accumulation.

3. Reasonable slope: For pipelines that need to discharge liquid, a certain slope should be designed to facilitate liquid discharge.

4. Thermal expansion compensation: In high or low temperature environment, the influence of thermal expansion of pipeline should be considered and expansion joints or elbows should be installed.

5. Support and fixing: The pipeline should be reasonably arranged with support points to avoid deformation or damage caused by vibration or gravity.

III. Connection method and sealing technology

Pipe connection is the key link in the design of vacuum system, and the commonly used connection methods include:

1. flange connection: suitable for large-diameter pipes, with good sealing performance, easy to disassemble and maintain.

2. clamp connection: suitable for small diameter pipeline, easy to install, but the sealing performance is relatively poor. 3. welding connection: applicable to small diameter pipeline, easy to install, but the sealing performance is relatively poor.

3. welding connection: applicable to sexual connection, high air tightness, but dismantling is difficult.

Sealing technology is the core to ensure the airtightness of vacuum system, commonly used sealing materials include:

- Rubber seals: suitable for low vacuum systems, low cost, but with poor high temperature resistance.

- Metal seals: suitable for high and ultra-high vacuum systems, high temperature and corrosion resistant.

- Polytetrafluoroethylene (PTFE) seals: suitable for more chemically corrosive environments.

Fourth, cleanliness control

The cleanliness of the vacuum system directly affects the performance and life of the system, so the cleanliness must be strictly controlled in the process of pipe design and installation:

1. pipe cleaning: before installation, the pipes should be thoroughly cleaned to remove oil, dust and metal chips.

2. Dust-free environment: The installation process should be carried out in a dust-free environment as far as possible to avoid contaminants entering the system.

3. Inert gas protection: Inert gas (such as nitrogen) can be used to protect against oxidation and contamination during welding or high temperature treatment.

V. Testing and acceptance

After the completion of piping installation, strict testing and acceptance must be carried out to ensure that the system performance meets the requirements:

1. Gas tightness test: Use helium mass spectrometer leak detector or pressure decay method to detect the gas tightness of the pipeline to ensure no leakage.

2. Vacuum test: Measure the ultimate vacuum of the system using a vacuum gauge to verify that it meets the design requirements.

3. flow test: detect gas flow through flow meter to ensure that the pipeline is well laid out and free from obstruction.

4. vibration test: detect the vibration of the pipeline under the running condition of the system to ensure that the support and fixing measures are effective.

VI. Safety and Maintenance

The piping design and installation of vacuum system should also consider the safety and maintenance convenience:

1. safety valves and pressure relief devices: safety valves and pressure relief devices protect the system in case of high pressure or sudden change in vacuum level.

2. regular maintenance: establish a regular maintenance program to check the condition of piping connections, seals and support structures, and replace damaged parts in a timely manner.

3. Operation training: Train operators to ensure that they are familiar with the operating principles and maintenance methods of the system.

Summarize

The piping design and installation of vacuum system is a complex project involving material selection, layout design, connection method, sealing technology, cleanliness control and testing and acceptance. Only by operating in strict accordance with the technical requirements in each link can the efficient and stable operation of the vacuum system be ensured. Designers and installers should fully understand the characteristics of the vacuum system, combine with specific application scenarios, formulate scientific and reasonable design solutions, and pay attention to detail control in the installation process, so as to finally realize the optimized operation and long-term reliability of the system.