Reinforced top cover structure for a chemical filter

A reinforced top cover structure for a chemical filter, comprising:

• a core board made of a metal material, and having a bottom surface, a top surface opposite to said bottom surface, an annular peripheral surface extending between said bottom surface and said top surface, a plurality of positioning holes extending from said bottom surface to said top surface, and a plurality of notches spaced apart from each other and extending inwardly from said annular peripheral surface;
• a plurality of positioning pillars each positioned on/in the core board, and having a middle section that extends through a corresponding one of said positioning holes, a lower positioning part that is connected to said middle section and extends downwardly from said bottom surface of said core board, and an upper section that is connected to the middle section and extends upwardly from said top surface of said core board;
• and
• a cover member made of injection molded plastic material, covering said core board, and having an outer peripheral surface that surrounds said annular peripheral surface of said core board, and a plurality of engaging grooves that are formed in said outer peripheral surface and that correspond respectively to said notches in position.