According to the material properties specified by the customer, if the material flow rate is uneven or material interruption occurs during the operation of the rotor pump, the rotor pump will run idly. To prevent damage to the mechanical seal caused by dry friction, a rotor pump with an oil-cooled mechanical seal structure is used. The mechanical seal of this rotor pump is equipped with an oil cup, whose main function is to optimize the lubricity of the mechanical seal. This enables the mechanical seal to withstand short-term idling of the pump and prevents dry grinding of the mechanical seal during operation.