Gas filter having gas mixing function

The utility model belongs to the field of gas filter, in particular to a gas filter having gas mixing function, comprising a casing body, an air inlet pipe and a mixed gas air outlet pipe welded at the top cover of the casing, a perforated plate, a filtering medium, a bottom cap and a sealing ring or a cushion. An upper perforated plate and the casing body are welded as an integration and the upper perforated plate and the top cover leave space forming a gas mixed zone. A lower perforated plate is overlapped at the lobe plate of the bottom cap while the lower perforated plate and the lower face of the bottom cap leave a gas premixed zone, and an air inlet pipe in sequence passes through the circular hole of the upper perforated plate, the filtering medium zone and the circular hole of the lower perforated plate extending into a gas premixed chamber. The gas like air, CO2, O2, N2, etc can enter a filter with definite quantity, passing through the filtering zone after being mixed at the premixed chamber and then flowing out through a mixed chamber after being thoroughly mixed. The design simplifies the equipment and the connection pipeline, is convenient to disassembly and change the filtering medium, effectively prolonging the service life of a secondary filter.