Error-proof structure of suction filter

The utility model provides an error-proofing structure of a suction filter, which comprises an upper shell and a lower shell which are butted with each other, a filter cavity is formed between the upper shell and the lower shell, filter paper and a net rack for supporting the filter paper are arranged in the filter cavity, a butt joint seam of the upper shell and the lower shell is of a rectangular structure, and a liquid outlet arranged on the top surface of the upper shell is positioned on the left side of the upper shell. A liquid inlet formed in the bottom surface of the lower shell is positioned on the right side; a first mistake-proof block is integrally arranged on the left side of the net rack, the left end of the first mistake-proof block is close to the left side wall of the liquid passing cavity, a second mistake-proof block is integrally arranged on the right side wall of the liquid passing cavity, the left end of the second mistake-proof block is close to the net rack, and the second mistake-proo