Low-pressure cleaning, derusting and cutting automatic conversion control valve with clear water abrasive as medium

The invention discloses a low-pressure cleaning, derusting and cutting automatic conversion control valve with a clear water abrasive as a medium. The valve consists of such elements as a mixing valve, a tapping hole plug, an O-shaped ring, a mixing nozzle body, a one-way valve, a combined washer, a filter, a filter plug, a parker water seal, a cylinder locking nut, a high-pressure spring, a negative-pressure cavity sand flowing pipe, an opening pad, a water seal, a washer, a nut, a balance water adjusting bolt, a fluorine rubber ring and a fluorine rubber pad. Pressure water enters the mixing nozzle body through the one-way valve, and is injected with high speed to form negative pressure; the abrasive enters the negative-pressure cavity sand flowing pipe under the acting force of negative-pressure cavity siphon for quick ejection; and the sand flowing pipe is connected with nozzles with different apertures to form different pressure sections to achieve object cleaning, derusting and cutting effects.