1. Long-term working vacuum degree.

2. The time required for exhausting to the working vacuum.

3. Vacuum system volume and out-gassing volume.

4. The media, temperature and characteristics of exhausting gas (such as: whether the exhausting gas contains flammable，explosive,toxic and corrosive contents, or a large amount of condensable vapor, or more dust and so on).

5. How to deal with the exhausting gas of vacuum system.

6. Other special requirements.

Appropriate and accurate selection of the type of vacuum equipment will decide if the exhausting requirement is satisfied, as well as the functioning efficiency,reliability and security.Please provide information as detailed as possible when placing the order for introducing vacuum equipment to the new process,so that ensure the customer to have the right choice.