... 1 series solid state H.F welder( 350 KW ) straight seam welding safety high efficiency ... QGT-1 series solid state H.F welder( 350 KW ) QGT-1 solid state H.F welder ... Sealed circulation system, distilled water cooling to avoid scaling.B. High efficiency of thermal radiating, low operating cost ... down the inner water (distilled water), no scaling.B. High efficiency of heat radiation, low cost, applicable ...