Gas-liquid separator and polishing apparatus

A polishing apparatus comprising:

• a polishing table having a polishing surface;
• a top ring configured to hold a substrate and press the substrate against the polishing surface;
• a processing liquid supply nozzle configured to supply a processing liquid to the polishing surface;
• a drain receiver disposed around the polishing table and configured to recover a gas-liquid two-phase flow that has been removed from the polishing table;
• and
• a gas-liquid separator configured to separate the gas-liquid two-phase flow, which has been recovered by the drain receiver, into a gas and a liquid and discharging the gas and the liquid,
• the gas-liquid separator including:
• a gas-liquid separation tank;
• a gas-liquid introduction pipe configured to introduce a gas-liquid two-phase flow into the gas-liquid separation tank, the gas-liquid introduction pipe extending in the gas-liquid separation tank;
• a spray nozzle configured to spray pure water toward the liquid that has been collected on a bottom of the gas-liquid separation tank;
• a drain pipe communicating with a liquid discharge outlet provided in the bottom of the gas-liquid separation tank;
• and
• an exhaust pipe communicating with a gas discharge outlet provided in a side wall of the gas-liquid separation tank, the gas discharge outlet being located above a lower end of the gas-liquid introduction pipe.