🔍 Key Concepts

• Mechanical foam proportioner / in-line eductor operation • Where air is introduced vs where foam concentrate is picked up in foam systems • What happens inside chamber E before the mixture exits the nozzle

💭 Think About

• Look at the shapes and locations of points C and D: which one is clearly positioned to be dropped into a foam concentrate container? • Follow the water path from A toward B: at what point could a low‑pressure area form that would suck (educt) something into the stream? • Think about how mechanical foam is normally made: do you first mix water and foam concentrate, then add air, or do you mix air and water first, then add foam?

✅ Before You Answer

• Identify which labeled part is likely the pick‑up tube for foam liquid by its length and position relative to a foam bucket. • Decide where air would naturally be drawn into the system (openings, screens, or mesh), and where water must already be flowing under pressure. • Confirm in the wording of each choice whether the sequence water + foam concentrate, then air (or another order) matches how a typical mechanical foam nozzle works.