A changeover valve includes: a valve body and an internal-communication air duct and a driving device arranged in the valve body; wherein the valve body is connected with a housing of a vacuum cleaner, the housing is provided with a ventilation opening, an air inlet duct for driven inlet air and an air outlet duct for driven outlet air, the ventilation opening is provided with a filter element, a first end of the internal-communication air duct is connected with the ventilation opening, an outer side of the internal-communication air duct is connected with the driving device, so that the driving device drives a second end of the internal-communication air duct to rotate by a preset angle, the second end of the internal-communication air duct is connected at the air inlet duct and the air outlet duct communicates with the external space.

A wet-and-dry floor brush for a vacuum cleaner, including a floor brush body including at least one dust suction port at a bottom of the floor brush body, and a wet mopping device including a base plate for mounting a mop cloth, and a liquid supply tank located on an upper side of the base plate, the base plate including liquid discharge holes, and the liquid supply tank includes an air inlet in communication with the outside. The bottom of the liquid supply tank has a liquid outlet in fluid communication with liquid discharge holes. The liquid outlet includes a valve for opening and closing the liquid outlet, and the liquid supply tank includes an external action member, the action member and valve configured to allow the transmission of motion to open or close the liquid outlet by operating the action member.

A wet-and-dry floor brush for a vacuum cleaner, including a floor brush body including at least one dust suction port at a bottom of the floor brush body, and a wet mopping device including a base plate for mounting a mop cloth, and a liquid supply tank located on an upper side of the base plate, the base plate including liquid discharge holes, and the liquid supply tank includes an air inlet in communication with the outside. The bottom of the liquid supply tank has a liquid outlet in fluid communication with liquid discharge holes. The liquid outlet includes a valve for opening and closing the liquid outlet, and the liquid supply tank includes an external action member, the action member and valve configured to allow the transmission of motion to open or close the liquid outlet by operating the action member.

A method to control an input power of a motor of an air-moving device that includes performing a measurement process to determine a first value of an operating parameter of the motor. The operating parameter is an operating pressure of the motor or an airflow rate through the motor. The method includes performing a determination process to determine a value of the inlet restriction of the air-moving device, based on the first value of the operating parameter of the motor and a first pre-determined relationship between values of the operating parameter of the motor and values of an inlet restriction of the air-moving device. The method also includes controlling, based on the determined value of the inlet restriction, the input power of the motor.

A method to control an input power of a motor of an air-moving device that includes performing a measurement process to determine a first value of an operating parameter of the motor. The operating parameter is an operating pressure of the motor or an airflow rate through the motor. The method includes performing a determination process to determine a value of the inlet restriction of the air-moving device, based on the first value of the operating parameter of the motor and a first pre-determined relationship between values of the operating parameter of the motor and values of an inlet restriction of the air-moving device. The method also includes controlling, based on the determined value of the inlet restriction, the input power of the motor.

A vacuum generator may comprise: a generator body provided with an air inlet, a contraction pipe section, an expansion pipe section, a negative pressure generation cavity, and an air outlet that may be sequentially communicated, where in a ventilation direction from the air inlet to the air outlet, a pipe diameter of the contraction pipe section may be gradually decreased, a pipe diameter of the expansion pipe section may be gradually increased, and the negative pressure generation cavity may be constructed to generate an inner cavity jet flow negative pressure when gas ejected from the expansion pipe section flows through the negative pressure generation cavity; wherein the generator body may be further provided with a negative pressure suction flow channel, and the negative pressure suction flow channel may comprise a suction port section and a reduced-diameter flow channel section.

A vacuum generator may comprise: a generator body provided with an air inlet, a contraction pipe section, an expansion pipe section, a negative pressure generation cavity, and an air outlet that may be sequentially communicated, where in a ventilation direction from the air inlet to the air outlet, a pipe diameter of the contraction pipe section may be gradually decreased, a pipe diameter of the expansion pipe section may be gradually increased, and the negative pressure generation cavity may be constructed to generate an inner cavity jet flow negative pressure when gas ejected from the expansion pipe section flows through the negative pressure generation cavity; wherein the generator body may be further provided with a negative pressure suction flow channel, and the negative pressure suction flow channel may comprise a suction port section and a reduced-diameter flow channel section.