Thermostatic Trap
Thermostatic Steam Trap Operating Principles
Thermostatic steam traps detect the variation in temperature between steam and condensate at the same pressure. The sensing device operates the valve in response to changes in the condensate temperature and pressure. These traps are generally used on applications with very light condensate loads.
How It Works
 | | Step 1 On start-up, the trap's charge is a liquid and the valve is open. Any condensate or air pushed ahead of the steam passes around the bellows and out of the trap. When steam comes into contact with the bellows, it heats the charge. The charge vaporizes and expands the bellows, which forces the valve into the seat-closing trap. |
 | Step 2 When the steam that is in contact with the bellows cools and condenses, so does the charge. The internal pressure of the bellows falls below the system pressure, pulling the valve from the seat and opening the trap. | |
Armstrong Thermostatic Trap Features
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| 1. | Small and lightweight. Wide range of pressures, loads, materials and connections available. | |
| 2. | Handles start-up loads. | |
| 3. | Sub cools condensate. | |
| 4. | Vents air at low pressures. | |
| 5. | Does not stand up well to water hammer. | |
| 6. | Thin, flexible metal parts are subject to corrosion damage. | |
| 7. | Can be damaged in freezing environments. | |
| 8. | Easily fouled by dirt. | |
| 9. | Fits into limited spaces. | |
| 10. | Back pressure only reduces the capacity of the trap. | |
| 11. | Can be used as air vents. Valve fully open at start-up. | |
