Retaining device for vacuum oil receiving machine

The invention relates to a retaining device for a vacuum oil receiving machine and provides a retaining device for a vacuum oil receiving machine with a simple structure and capabilities of preventing oil contamination from being recovered into a negative pressure passage and improving the reliability of recovering the oil contamination. The vacuum oil receiving machine comprises a hollow tank body, wherein a first port and a second port are formed in the upper part of the tank body; the first port is connected with a negative pressure source through a pipeline; the second port is connected with an oil suction pipeline; and an oil outlet pipeline is formed at the lower part of the tank body. The retaining device comprises a filter funnel and a floating ball, wherein the floating ball is movably arranged in the filter funnel; the filter funnel is connected with the first port and is also arranged in the tank body; and the floating ball is used for blocking the first port. The retaining device is simple and con