| 摘要 |
PROBLEM TO BE SOLVED: To provide a multistage vacuum pump that can prevent a cylinder from corroding and can cool the inside of the multistage vacuum pump without complicating the structure of the cylinder.SOLUTION: Partition walls 14 and 15 of a cylinder 1 are formed on the inside of a cylinder body 11 and define a first pump chamber 31, a second pump chamber 32, and a third pump chamber 33. A through-hole 11a is formed in the cylinder body 11, and a cooling pipe 51 is provided so as to be inserted into the through-hole 11a. The cooling pipe 51 is led from the outside of the cylinder 1 into the cylinder 1 along the through-hole 11a, passed through the partition wall 14, and led to the outside of the cylinder 1. The partition wall 14 inside the cylinder 1 can be cooled by passing a cooling medium through the cooling pipe 51. Because a passage through which the cooling medium is passed is formed in the cooling pipe 51, which is a member different from the cylinder 1, the cylinder 1 can be prevented from corroding, and the cylinder 1 can be easily produced without complicating the structure of the cylinder 1. |
