🔍 Key Concepts

• Oily water separator operation and how it keeps oil from being pumped overboard • Difference between interface/level sensing and temperature sensing in control circuits • How a weir plate and sensing probes are used together to switch between recirculate and discharge modes

💭 Think About

• Look at where the short sensing element marked "S" is physically located in the tank in Fig. A – is it near the oil–water interface, at the top vapor space, or near any heating element? • Compare the operation shown in Figs. B, C, and D: when the level of oil or water changes, which valves change position, and which mode (recirculation vs. discharge) is affected? • Ask yourself: would corrosion‑protection anodes or temperature bulbs normally be shown as paired, vertical probes close to a weir in an oily water separator schematic?

✅ Before You Answer

• Verify what the legend at the bottom of GS‑0113 says about oil vs. water flow in each figure and relate that to the position of the sensing elements. • Check whether anything in the diagram indicates a temperature control loop (heater symbol, steam or electric supply, temperature controller) connected to the short sensing element. • Confirm whether the short sensing probe at "S" changes the system from recirculation to overboard discharge or simply maintains level relative to the weir plate.