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