Which method uses a device to entrain foam concentrate into the water stream?

Which method uses a device to entrain foam concentrate into the water stream?

• A. Eduction
• B. Injection
• C. Batch-mixing
• D. Premixing

Answer: (A)

Eduction relies on a device—an eductor or aspirator—that uses the Venturi effect to pull foam concentrate into the water stream. As water flows through the eductor, its speed increases and the pressure drops, creating suction that draws concentrate from its reservoir into the line and mixes it with the water downstream. This is distinct from other methods: injection uses a pump to force concentrate into the line, premixing combines concentrate with water before discharge, and batch-mixing blends them in a separate vessel prior to discharge.

Eduction relies on a device—an eductor or aspirator—that uses the Venturi effect to pull foam concentrate into the water stream. As water flows through the eductor, its speed increases and the pressure drops, creating suction that draws concentrate from its reservoir into the line and mixes it with the water downstream. This is distinct from other methods: injection uses a pump to force concentrate into the line, premixing combines concentrate with water before discharge, and batch-mixing blends them in a separate vessel prior to discharge.