The challenge for vacuum pumps depends on the residual gases which are in the “empty” bottles. They might be air and moisture (if the bottle is new) or numerous types of harsh process gases, e.g., those used in chemical or semiconductor applications.
Choosing the correct vacuum pump therefore depends on the type of gas. Historically, vacuum pumps typically used were two-stage, oil-sealed rotary-vane pumps. However these days, dry compressing pumps have become more and more standard, as these can also handle aggressive gases.
Leybold offers a full vacuum product portfolio of vacuum pumps to satisfy the needs of every gas producer.