| 摘要 |
<p>A main casing (28) has a first gearwheel (26) to engage with a second gearwheel (27). Tight to the external diameter of these gearwheels and fixed on the main casing, an inner case (29) surrounds this gear traction. A pump creates a partial vacuum in the inner case's inner space (30). The space between the inner case and the main casing is kept under atmospheric pressure.</p> |
