Can the hydraulic tank be used as a pneumatic tank?

I can't. Pressure tank uses the compressibility of air to adjust and store the water tank to maintain the required pressure, so it is also called pneumatic water supply equipment, and its function is equivalent to water tower and high-rise swimming pool. The hydraulic tank cannot be used as a pneumatic tank. Pressure tank is used in closed water circulation system to balance water quantity and pressure, avoiding frequent opening of safety valve and frequent replenishment of automatic water replenishment valve.