The present invention provides a multi-medium mixing device for an ultra-
high voltage converter
transformer, comprising a composite venturi tube and a mixing
pipe connected in sequence, wherein the composite venturi tube comprises an inner venturi tube connected to a
dry powder pipe and an outer venturi tube connected to a foam
pipe, the inner venturi tube is nested in the outer venturi tube, the outer venturi tube is connected to the mixing pipe, and the outlet of the inner venturi tube is located before the outer
throat of the outer venturi tube. The present invention also provides a fire fighting
system using the mixing device. The advantages of the present invention are that after the ultra-fine
dry powder enters the inner venturi tube and passes through the inner
throat, the cross-sectional area of the pipe is reduced, thereby accelerating the ultra-fine
dry powder, and the ultra-fine dry
powder can be accelerated and mixed with the
compressed air foam, and then accelerated through the outer
throat, promoting uniform mixing of the two media, so that the
compressed air foam can effectively wrap the ultra-fine dry
powder without the phenomenon of dispersed distribution.