Design and Performance Study of Multi-chamber Powder Spraying Gun under Digestive Tract Endoscope

To improve unstable powder delivery, uneven spraying, and poor terminal output control during digestive tract endoscopic submucosal dissection, a multi-air chamber powder spraying gun was developed for endoscopic working-channel application. Under a single gas source, the device uses a fluidizing chamber, a supplementary chamber, and a piston linkage mechanism for coordinated control of powder fluidization and transport. Transient CFD simulations under six typical conditions and prototype experiments were carried out. The results showed that increasing the chamber depth ratio shifted the pressure and velocity fields toward the fluidizing chamber side, and the T2 structure outperformed the T5 structure under the same ratio. T2-R1:1 achieved the highest powder output, while T5-R1:2 showed the lowest. These findings confirm that proper chamber matching is critical for device performance.