What principle does the in-line educator utilize to draft foam into a water stream?

The in-line educator uses the Venturi principle to draft foam into a water stream. This principle is based on the behavior of fluids moving through a constricted pathway. When water flows through the educator, it experiences a decrease in pressure as it passes through the narrower section. This drop in pressure creates a vacuum effect that draws foam concentrate from a nearby container into the water stream.

The Venturi effect is fundamental in many applications, including fire suppression, as it efficiently mixes the foam concentrate with the water, producing a foam solution that can effectively extinguish various types of fires. This principle allows for the effective use of foam without requiring additional pumps or complex systems, making it an important tool for fire service professionals.