Which type of foam proportioner relies on the Venturi effect?

The type of foam proportioner that relies on the Venturi effect is the eductor. The Venturi effect involves a reduction in fluid pressure that occurs when a fluid flows through a constricted section of pipe. In the case of an eductor, the flow of water through the nozzle creates low pressure at the venturi throat, which draws foam concentrate into the water stream, allowing for the mixing of the foam and water.

This principle is essential in fire suppression as it effectively mixes the foam concentrate with water under pressure, facilitating a consistent and reliable foam output that can be used to combat various types of fires. The eductor functions best when the water supply pressure is well-maintained, ensuring adequate suction of the foam concentrate.

In contrast, other types of proportioners, such as injectors, aspirators, and inductors, operate on different principles or mechanisms for mixing foam and water. Understanding how each proportioner works is crucial for effective fire suppression strategies.