If a liquid-filled PV breaker has relieved a vacuum in a tank, what must be done before continuing operations?

When a liquid-filled pressure vacuum (PV) breaker has relieved a vacuum in a tank, it is essential to refill the breaker with liquid before continuing operations. The function of the PV breaker is to maintain the appropriate pressure in the tank by allowing air to enter or exit as necessary while preventing the escape of liquids or vapors. If the breaker has operated and allowed liquid to escape, it can create a situation where the PV breaker is not effective in maintaining the necessary pressure in the tank.

Refilling the breaker ensures that it can function correctly by restoring the liquid seal that provides the pressure differential needed for safe and efficient operation of the tank. Without sufficient liquid in the breaker, there could be a risk of pressure fluctuations, potential tank implosion, or overpressure scenarios due to faulty operation of the PV breaker.

While checking the temperature of the tank, calibrating the pressure gauge, and purging the tank with inert gas are important safety and operational measures, they do not directly address the immediate need for the PV breaker to function correctly after it has relieved a vacuum. The first priority must be to ensure that the PV breaker is properly filled with liquid to resume safe operations.