Extension shaft variable-frequency three-phase electric motor for pump for conveying liquid nitrogen

Abstract

The invention discloses an extension shaft variable-frequency three-phase electric motor for a pump for conveying liquid nitrogen. The extension shaft variable-frequency three-phase electric motor comprises a motor main body and a motor shaft; the motor main body is fixed on a motor stand which is of a disk-shaped structure and is coaxial with the motor main body; the motor stand is positioned at the front end of the motor main body and is provided with a center through hole; the motor shaft is an extension shaft running through the motor stand and comprises a motor spindle and a transmission shaft which are integrally formed; a mechanical sealing part for blocking contact between the liquid nitrogen and the motor spindle is arranged at a matched position of the transmission shaft and the center through hole of the motor stand; and a cooling fan is positioned at the rear side of the motor spindle and is at a distance from the rear end face of the motor spindle. According to the invention, by arranging the mechanical sealing part at the matched position of the transmission shaft and the center through hole of the motor stand, contact between the liquid nitrogen and the motor spindle is blocked, so that the phenomenon of a low temperature of a bearing at one side of the motor spindle, which is close to the liquid nitrogen, is effectively avoided, the probability of failure of bearing grease is reduced and the service life of the bearing is prolonged, thereby prolonging normal service time of the electric motor.

Description

technical field [0001] The invention relates to the technical field of motors for high-speed pumps used for transporting low-temperature media, and more specifically relates to an extended-shaft variable-frequency three-phase motor for pumps transporting liquid nitrogen. Background technique [0002] During the transportation of liquid nitrogen, it is sometimes necessary to drive the transmission through a pump. This kind of pump is generally realized by driving the impeller by a motor. The impeller and the front end of the motor shaft are immersed in liquid nitrogen at a temperature of -196°C. The existing motor shaft is relatively short, because the impeller and the front end of the motor shaft are soaked in low-temperature liquid nitrogen for a long time, which will cause the bearing temperature on the side of the motor shaft close to the liquid nitrogen to be low. When the temperature is lower than -75°C, the bearing The lubricating grease will fail, which will lead to b...

AI Technical Summary

Problems solved by technology

The existing motor shaft is relatively short, because the impeller and the front end of the motor shaft are soaked in low-temperature liquid nitrogen for a long time, which will cause the bearing temperature on the side of the motor shaft close to the liquid nitrogen to be low. When the temperature is lower than -75°C, the bearing The lubricating grease will fail, which will lead to the failure of the bearing and seriously affect the normal use of the motor.

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