Electromagnetic blower and two-passage air supply apparatus using the same

A two-passage air supply apparatus comprising:

• an electromagnetic blower for supplying aeration air into a septic tank, comprising an electromagnet having a core, a first coil wound around the core, and a second coil wound around the core and connected in series to the first coil;
• a vibrator capable of reciprocating when driven by a magnetic force of the electromagnet, which is generated from an alternating current supplied to the first and second coils;
• a diaphragm attached to an end of the vibrator, for discharging compressed air;
• switching means for supplying the alternating current to one of the first and second coils;
• and a timer for driving the switching means, wherein the switching means supplies the alternating current to both the first and second coils so that the blower operates in a first mode to supply aeration air into the septic tank, and the switching means temporarily supplies, in response to a control signal from the timer, the alternating current to only one of the first and second coils so that the blower temporarily operates in a second mode to supply reverse-cleaning air is supplied into the septic tank,
• a first air diffuser pipe for aeration for sewage purification;
• a second air diffuser pipe for reverse cleaning;
• and
• a switching valve for supplying compressed air from the electromagnetic blower to a selected one of the air diffuser pipes,
• wherein the compressed air is supplied to both the first air diffuser pipe and the second diffuser pipe while the electromagnetic blower is operating in the second mode.