a, high-vacuum

 b, to maintain a high pumping speed limit up to the pressure

 c, low-noise

 d, containing mandatory pumps, lubrication full, reliable performance

 e, reliable institutions to prevent the return of oil, the oil does not return

 f, gas operation in the town, remained low pressure limit

 g, in addition to pumping water vapor and strong

 h, into the air to keep 1.33 × 103pa, still functioning in a row

 i, not oil