Liquid or solid sulfur goes into pipelines insulated by steam coil and jacket, then introduced to the sulfur melting tank, afterwards pumped to the high-level tank and continues transfer to the sulfur burner by submerged gear pump or gear pump insulated by the steam jacket. By adopting the mass-flow meter and VFD of the gear pump, the flow of liquid sulfur is controlled at a stable rate.     Features: WEIXIAN liquid sulfur gear pump won't be blocked by impurities and the flow rate of liquid sulfur is controlled by the mass flow meter and VFD, so the flow is stable and accurate; also achieves online operation parameters readable, which provides the best convenience for controlling SO3 concentration, plant performance adjustment and products switching.