fusion rate of prefused flux is increased with the increase in particle size.This is due to the relation of the particle size to the heat transfer in flux layer. ACKNOWLEDGEMENT Mr.Wang Xin and Li Xiuwen have kindly assisted in the experimental work,grateful for their help. REFERENCES 1 Sato R.Steel Making Proceedings ISS-AIME,1979;62:48 2 McCauley W L,Apelian D.Iron and Steel Making,1983;(1):1984 3 Gray R,Marston H.Steelmaking Proceedings,ISS-AIME,1979; 62:93 4 Jin Shantong.Iron and Steel of China 1980;15 (5):14 5 Jin Shantong.The 3rd China-Japan Symposium on Science and Te- chnology of Iron and Steel,1985;410 6 McCauley W L.Iron and Steel Engineer,1985;(9):36 7 Jin Shantong.J of Beijing University,of Iron Steel Techno- 1o9y,1981;(1):15 8福井敞。J of the Iron&Steel Institute of Japan,1974;(11):396 GPH Tyde Tubular Jet Heat-Exchanger GPH is a new high performance heat-exchanger.It is constructed by stan- dard special section tubes.Multistage Jetting is used on the air side,so the ef- ficiency of heat-exchanger increases considerably.The overall coefficient of heat transfer is as high as 45~60W/m2C.The pressure loss of air side is about 600 T Pa per stage.It is with lower wall temperature,figure impacted and lighter wei- ght. GPH is suitable for various industrial furnaces and kilns for utilizing waste heat to preheat air used in combustion.The air can be preheated to 300 to 500C according to the temperature of stack gases.At present it is a modern and ef- fective device of energy saving for industrial furnaces and kilns. GPH heat-exchanger and QRF burner can be worked together to form a complete set for industria!furnaces and kilns. 525从 · ， · ‘ 夕 犷。 夕 一 ， ， 夕 ， ， · ， ￡ 夕 ，， 一 ， · 无 一 夕 户。 ￡ 泞 夕夕 了 ， 夕 九 ， · ‘ 夕 夕， 。 夕夕 ， 福 井 敞 · 几 ， 、 一 》 一 一 · ， ， 一 · 一 “ 。 · · 从 从 ， ， ， 走 。 、 矶 ， 住 “ 一 压 · 一 啼卜 月 卜 月卜 」卜 刁卜 月 卜 月卜 月 卜 月 卜 月毛一 月 卜 月于 书卜 一 卜 ‘ 令卜 书 一 」卜 嘴卜 弓卜 书卜 月 卜 弓卜 月 卜 月于 一北一华月于 月乍 月 卜 刁 ， 卜 手卜 弓备 ， 令卜 弓卜 弓于 佬卜 斗卜 月卜