S₁ : A single device can heat fluids without requiring an electrical element.
S₆ : Because there is no electrical element, there is no risk of fire, so the system is suitable for dangerous environments.
P : A heat exchanger transfers heat from the central cavity to an air heater, a water heater or an industrial processor.
Q : It has a container like the crank case of a car’s engine, which contains the fluid to be heated.
R : Compression and friction at the nozzles heat the fluid, so that the temperature in the central cavity rises steadily.
S : A motor and pulley inside the container turn a rotor wheel, which in turn forces the fluid again and again through narrow nozzles into a central cavity.
The correct sequence should be