苏联焊工革新者莫洛查夫創造一种管子轉动接头的第一層焊縫不用任何垫环的自动焊接法。按照这种方法,第一層焊縫是在仰焊位置焊接,熔剂是利用螺旋输送机送入电弧区內。在螺旋输送机內部装有焊咀。当螺旋输送机轉动时,熔剂被送到电弧区。此时熔渣浮到焊池表面, Molotov, a Soviet welder innovator, created an automatic welding method that does not require any grommets for the first weld of a pipe-swivel joint. According to this method, the first layer of weld is soldered at the pick-up position and the flux is fed into the arc area using a screw conveyor. In the screw conveyor equipped with welding Tsui. When the screw conveyor rotates, the flux is sent to the arc zone. At this point slag floating to the surface of the weld pool,