... Φ20mm, Φ25mm, Φ32mm, Φ38mm, Φ42mm, Φ50mm, Φ100mm and other dimensions protective sleeve of the crystallizing dish for various ... but also the defect of being preheated and explode easily.Using methodWhen the protective sleeve is ... on the 2-3 threads for two circles, and then screw the 2-3 threads completely ... till the graphite mold and the bottom of the protective sleeve coincide ...