Air extracting device and method for calculating remaining time required for extracting action

An air extracting device (2) for extracting air from a sealed bag (1), comprising:

• a power port (22), connected to a power supply (3);
• a processor (21) electrically connected with the power port (22), configured to receive a load current provided by the power supply (3) through the power port (22);
• a wireless transmitting unit (25) electrically connected with the processor (21), configured to wirelessly connect to an external mobile device (4) for the air extracting device (2);
• a motor (23) electrically connected with the processor (21), configured to receive the load current from the processor (21) for rotating;
• and
• an air extracting unit (24) electrically connected with the motor (23), jointed with the sealed bag (1) for the air extracting device (2), and driven by the motor (23) to execute an extracting action for extracting air from a confined space inside the sealed bag (1);
• wherein, the processor (21) is configured to monitor the load current required by the motor (23) while the air extracting unit (24) executes the extracting action, and is configured to calculate a remaining time required for the extracting action to be completed based on a variation of the load current, wherein the load current is inversely proportional to an air amount remained in the confined space;
• wherein, the processor (21) transmits the calculated remaining time to the mobile device (4) to be displayed thereon through the wireless transmitting unit (25).