WATER JET SPRAY NOZZLE, WATER JET SPRAY DEVICE, CLEANING METHOD USING WATER JET, GASTROINTESTINAL TRACT CLEANING DEVICE, AND GASTRIC WALL CLEANING DEVICE
A water jet spray nozzle has a flow path including, from the upstream side to the end of the flow path, a small-diameter portion having a small inside diameter, an expanded portion having a larger inside diameter than the small-diameter portion, and a jet orifice having a smaller inside diameter than the expanded portion. The water jet spray nozzle is configured such that water passing through the flow path with a pressure of 0.2 to 0.6 MPa is retained in the expanded portion to as to generate cavitation bubbles from the small-diameter portion to the expanded portion. The inside diameter of the small-diameter portion § is 0.5 to 0.7 mm while the inside diameter of the jet orifice is 1 to 1.3 times larger than that of the small-diameter portion.
