Patent attributes
An internal cleaning apparatus includes a rotary shaft which, having a liquid flow passage, is provided so as to be axially rotatable, a revolving rotary shaft which, having a liquid flow passage connected to the liquid flow passage and being provided in a direction substantially perpendicular to the rotary shaft, is installed so as to be revolvable about the rotary shaft and axially rotatable, and a nozzle provided at a leading end of the revolving rotary shaft, wherein a gas flow passage is provided along the liquid flow passage of each of the rotary shaft and the revolving rotary shaft from a gas inflow opening provided in the rotary shaft, wherein a configuration is such as to eject a gas-liquid mixture flow having a gas supplied from outside the object to be cleaned mixed with the liquid ejected from the nozzle.