Flange sealing device

The invention provides a flange sealing device, which is applied to a process pipeline in an oil and gas field station. The flange sealing device comprises annular gaskets and two oppositely-arranged beveled flanges, wherein the annular gaskets are clamped between the two beveled flanges; each beveled flange has a first end and a second end; the first ends are used for being connected with a pipeline; the second ends of the two beveled flanges are oppositely arranged; annular sealing grooves capable of accommodating the annular gaskets are formed in the end faces of the second ends of the two beveled flanges; the beveled flanges are provided with grease injection channels; the grease injection channels are provided with grease inlets and grease outlets; the grease inlets are communicated with the outside; grease injection check valves are arranged at the grease inlets; and the grease outlets are formed between the annular sealing grooves and inner holes, and communicated with the joint of the annular sealing