Low-cost scale-inhibiting vertical pre-filter

The utility model provides a low-cost scale-inhibiting vertical pre-filter which comprises a filter body, the filter body is of a tubular structure, a water inlet is formed in the side face of the filter body, a water outlet is formed in the upper portion of the filter body, and a water outlet filter screen is installed on the upper portion of the water outlet. A drain outlet is formed in the lower part of the filter body; a filter screen fixing groove is formed in the water inlet in the axis direction of the water inlet, the filter screen fixing groove extends into the filter body and is connected with a filter screen fixing groove formed in the inner wall of the cavity into a whole, a filter screen is installed in the filter screen fixing groove, and a scale inhibitor containing cavity is formed between the filter screen and the water outlet filter screen; a water retaining cap is installed at the end of the water inlet, and a water inlet hole is formed in the water retaining cap and located on the lower si