🔍 Key Concepts

• Direct sensing steam pressure gauge construction and how steam can damage it • Purpose and shape of a siphon (pig-tail) tube in steam service • How condensate (water) is used to protect instruments from high steam temperature

💭 Think About

• How does the temperature of live steam affect the internal parts (Bourdon tube, springs, etc.) of a pressure gauge? • What role does a loop or pig-tail in the line play in forming and holding a water seal between the steam line and the gauge? • Would the orientation of the siphon affect its ability to trap condensate and keep steam from directly entering the gauge? If so, how?

✅ Before You Answer

• Identify which option(s) involve a water/condensate seal between the steam and the gauge mechanism. • Consider which orientation of a siphon tube will most reliably trap condensate and keep it in place during normal operation. • Verify whether simply restricting flow (needle valve) or insulating the gauge alone can prevent direct steam contact and high-temperature damage.