Foam generators are used in fire-fighting installations at industrial facilities of petrochemical industry/ They can be equipped with an oscillator to provide a greater range of foam supply, providing a larger irrigation area and increasing the efficiency of the spray. In order to achieve this, the foam generator is characterized by its high expansion ratio.

In the exemplary embodiment of the invention, the generator consists of a hollow cylindrical stator body 1 having a diameter D and a hollow cylindrical rotor member coaxially driven therein and containing a mixing chamber. The outer sides of both the stator body and the rotor body are provided with rings of radial pins having a constant cross section. Viewed in axial direction, the pins in both the stator and rotor rings are alternately disposed.

A solid-liquid interface-treated foam (SLITF) is fabricated by absorbing distilled water into a cellulose foam. This enables charges generated by friction energy during sliding motion between the two metal contacts to be separated and transferred through the conductive path formed by hydrogen-bonded network of water molecules in the SLITF. This results in the SLITF forming an effective dielectric layer.

The generator possesses an excellent performance, especially when the SLITF is used in combination with a triboelectric generator (TEG) and a metallized mica substrate. The TEG is composed of a polytetrafluoroethylene (PTFE) film, indium tin oxide (ITO), copper (Cu) and aluminum (Al) tapes, resistors and capacitors. The TEG is connected to the SLITF through a triboelectric sensor, which has a low resistance (0.15 m) and a high output voltage (20 V). The result is a generator with superior properties and lower cost.