How is a vacuum created?
The term vacuum is commonly used to describe a space that is largely free of air. A vacuum is created by removing the gas from a space (in our case, a chamber) using a vacuum pump. This reduces both the pressure and density of the gas. The remaining gas pressure is known as the final vacuum, and is measured in mbars as zero pressure. This zero pressure is much lower than the atmospheric pressure under normal conditions.
What kinds of vacuum are there?
Vacuums are classified into four types, depending on the level of residual pressure:
- Rough vacuum: 1013 – 1 mbar
- Fine vacuum: 1 – 10-3 mbar
- High vacuum: 10-3 – 10-7 mbar
- Ultra-high vacuum: below 10-7 mbar
Vacuum packaging machines work with a final vacuum of up to 2 mbar, and therefore represent a rough vacuum.
What does evacuation time mean?
Evacuation time refers to the time required to lower the pressure. The evacuation time is determined by a number of factors:
- Desired final vacuum
- Vacuum capacity
- Vacuum pump
- Line cross-section
- Leaks in the system
- Moisture content of the product/space to be evacuated