| 摘要 |
A double vacuum pump apparatus (Y2) includes positive displacement vacuum pumps (40A, 40B) and lines (52, 60). Each of the vacuum pumps includes a suction port (41) and a discharge port (42), and a pressure detector (80) is provided in the vicinity of the suction port (41) of the double vacuum pump apparatus (Y2). The line (52) connects the discharge port (42) of the vacuum pump (40A) to the suction port (41) of the vacuum pump (40B). The line (60) has an end (E6) and an end (E5) that are connected to the connection line (52), and includes a buffer tube (Z1) and an on-off valve (61) located between the tube (Zl) and the end (E5). A pressure detection signal from the pressure detector (80) is used as an on/off signal for the on-off valve (61). |
