Working Principle of Micro Air Pump (Diaphragm Vacuum/Air Pump, the type used for microplate washers)

1. Core Structure

• Electromagnetic coil + vibrating armature
• Elastic rubber diaphragm
• Pump chamber, inlet one-way valve, outlet one-way valve
• Air intake port & exhaust port

2. Operating Principle

1. Electromagnetic vibration drive

    

   When the coil is energized, alternating current generates a changing magnetic field, which continuously pulls and releases the metal armature at a high frequency. The armature connects to the rubber diaphragm, driving the diaphragm to reciprocate back and forth inside the pump cavity.
2. Expansion stroke (air suction)

    

   The diaphragm moves outward, expanding the internal pump chamber volume. Internal air pressure drops below atmospheric pressure, the outlet valve closes tightly under air pressure, and the inlet one-way valve opens. External air is sucked into the pump cavity through the air inlet.
3. Compression stroke (air discharge)

    

   The diaphragm moves inward, shrinking the pump chamber volume. Internal air pressure rises sharply. The inlet valve closes to prevent air backflow, and the outlet one-way valve is pushed open by compressed air. Air is forced out from the exhaust port to form positive pressure airflow.
4. Continuous cycle

    

   Alternating current makes the diaphragm vibrate hundreds of times per minute. Repeated suction and compression create stable continuous airflow.

• If you block the exhaust port: it forms a positive pressure air pump (air blowing).
• If you block the inlet port: it forms a micro vacuum pump (negative pressure suction, used for liquid waste extraction in microplate washers).

3. Key Feature for Microplate Washer

Supplementary: Other Mini Air Pump Types

1. Piezoelectric micro air pump: Uses piezoelectric ceramic deformation to push the diaphragm, ultra-small size, low flow.
2. Gear micro air pump: Rarely used in medical washers, mostly for industrial gas transfer.