The A48sY-C high-temperature and high-pressure spring fully open safety relief valve is suitable for working temperatures ≤ 425 ℃; A48sY-I high-temperature and high-pressure spring fully open safety relief valve is suitable for working temperatures ≤ 510 ℃; The A48sY-V type high temperature and high pressure spring full open safety relief valve is suitable for steam and other media with a working temperature of ≤ 560C or on pipelines, as an overpressure protection device.