A48sH-C high-temperature spring fully open safety relief valve is suitable for working temperatures ≤ 425 ℃ A48sH-I high-temperature spring fully open safety relief valve is suitable for working temperatures ≤ 510 ℃ The A48sH-V high-temperature spring fully open safety relief valve is suitable for equipment or pipelines with steam and other media working at temperatures ≤ 560 ℃, as an overpressure protection device.