Patent ID: 8579601
Filing Date: 2013-11-12
Classification: F01C,F04C

Abstract:
1. A multistage dry vacuum pump, comprising: a first stage cylinder body, the first stage cylinder body including a first stage cylinder and a pair of first stage rotors located in the first stage cylinder, the first stage rotors being rotatable with respect to each other; a final stage cylinder body, the final stage cylinder body including a final stage cylinder and a pair of final stage rotators located in the final stage cylinder, the final stage rotors being rotatable with respect to each other, the first stage cylinder body and the final stage cylinder body being arranged in series such that a gas compression ratio increases as gas moves from the first stage cylinder body to the final stage cylinder body; a main shaft configured to rotate one of the first stage rotors and one of the final stage rotors; a driven shaft configured to rotate the other of the first stage rotors and the other of the final stage rotors; a motor to rotate the main shaft; an inlet port connectable between an external facility and the first stage cylinder body to guide gas flow into the first stage cylinder; and an exhaust port connected to the final stage cylinder body to discharge gas, wherein the first stage cylinder body includes a gas passage formed at an outer side of the first stage cylinder, the gas passage of the first stage cylinder body being configured to transfer compressed gas from an exhaust space of the first stage cylinder, wherein the final stage cylinder body includes a gas passage formed at an outer side of the final stage cylinder, the gas passage of the final stage cylinder body being configured to transfer compressed gas from an exhaust space of the final stage cylinder, wherein only one of the first stage cylinder body and the final stage cylinder body includes a cooling water jacket formed adjacent an outer side of the gas passage of the corresponding cylinder body to surround the gas passage of the corresponding cylinder body, and wherein said only one of the first stage cylinder body and the final stage cylinder body includes a communication passage connecting the gas passage of the corresponding cylinder body to the corresponding cylinder such that compressed gas cooled by the cooling water jacket is returned to the exhaust space of the corresponding cylinder.