Basic Steam Trap Operation and its operation
- 1. ©2008 Armstrong International, Inc. Basic Steam Trap Basic Steam Trap Operation Operation
- 2. What MUST a Steam Trap do? What MUST a Steam Trap do? A Steam Trap must remove condensate, air, and CO2 out of the system as quickly as it collects. 2 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R
- 3. 3 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Minimize steam lose Corrosion resistance CO2 Venting Freedom from dirt problems Long life and dependable service Air Venting Operation against backpressure A Steam Trap Must Also: A Steam Trap Must Also:
- 4. 4 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R What makes up a Steam Trap What makes up a Steam Trap • A Steam Trap has an orifice • An orifice alone is not a steam trap – If flow changes, orifice is not correct – If pressure drop changes, orifice is not correct – The orifice must change size as conditions change Orifice Inlet Connection Outlet Connection Body
- 5. 5 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R What makes up a Steam Trap What makes up a Steam Trap • A Steam Trap should have a valve – A valve may be fully opened and fully closed or modulated to vary the size of the orifice as conditions change Orifice Inlet Connection Outlet Connection Body Valve
- 6. 6 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R What makes up a Steam Trap What makes up a Steam Trap • A Steam Trap should have an Operator – An operator senses when to move the valve and supplies the power to move the valve – Traps are different in the types of valve and the types of operator they use Inlet Connection Outlet Connection Body Valve Orifice Operator
- 7. Trap/Operator Types Mechanical Use difference in density between steam and condensate to operate valve. A float operates the valve. Thermodynamic Steam (flash) – flow operates valve Thermostatic Sense temperature change of condensate to operate valve 7 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R
- 8. 8 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Thermostatic Trap Types Thermostatic Trap Types • Bellows balanced pressure – High capacity • Wafer/Diaphragm balanced pressure – Low capacity • Bi-metallic – High and low capacity
- 9. 9 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Bellows Balanced Pressure Bellows Balanced Pressure Steam Steam Condensate Liquid fill Bellows Valve Seat
- 10. 10 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Bellows Balance Pressure Bellows Balance Pressure Bellows Balance Pressure Modulation Poor Backpressure Good Dirt Fair Wear Fair Water Hammer Poor Freezing Good
- 11. 11 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Simple Bi-Metal Element Simple Bi-Metal Element High expansion metal Low expansion metal Cold Hot
- 12. 12 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Simple Bi-Metal Operation Simple Bi-Metal Operation Valve inside trap • Pressure holds valve closed; valve toggles • Back pressure can blow trap open • Opening and closing temperatures wide apart • Must sub-cool deeply to prevent steam loss
- 13. 13 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Bi-Metal Disks Bi-Metal Disks Valve in outlet • Pressure opposes closing. • Does not toggle. • Some thermodynamic action; roughly follows steam saturation curve. • Acts as check valve when pressure is lost. • Good for use in super- heated applications.
- 14. A. Trap body B. Disk bonnet C. Disk D. Inner seat ring E. Outer seat ring F. Inlet port G. Outlet port and groove Disk Trap Orifices in Series Disk Trap Orifices in Series P2 A B C D E F G H D E F G H E D P1 P3
- 15. 15 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Disk Trap Start-up Disk Trap Start-up • Condensate pressure pushes disk off seat • Full capacity flow • Two pressure drops
- 16. 16 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Disk Trap Flashing Steam Disk Trap Flashing Steam • Condensate near steam temperature flashes to steam in inlet port • Pressure drops with flow through restriction under disk • Pressure difference (P2 - (<<P2)) slams disk onto seats P1 P2 <<P2 P3
- 17. 17 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Disk Trap Closed Disk Trap Closed • P2 – P3 x disk area > P1 x inlet port area + P3 x outlet port area • Closing force greater than opening forces so disk stays on seat • Condensing flash steam above disk relieves pressure until opening forces are greater; disk snaps open • A bleed groove is used to help with control of the pressure in the control chamber.
- 18. 18 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Disk and Seat Wear Disk and Seat Wear • Disk slammed hard onto seats and rolls as it seats – Edge of disk wears rapidly – Edge of outer seat ring wears rapidly • High velocity flow of condensate flash steam and dirt between disk and inner seat ring – Inner seat ring wears rapidly – Disk surface erodes rapidly Uneven contact of disk on seat causes wear Disk Wear Seat Wear Flat valve and seats require near perfect flatness to seal Two seats to seal
- 19. 19 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Thermodynamic Traps Thermodynamic Traps Bellows Balance Pressure Thermodynamic Traps Modulation Poor Fair Backpressure Good Poor Dirt Fair Poor Wear Fair Poor Water Hammer Poor Good Freezing Good Good
- 20. 20 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Mechanical Types Mechanical Types Float & Thermostatic Inverted Bucket Linkage Fixed Pivot Air Vent Valve Valve Ball Seat
- 21. 21 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Simple Float Trap Simple Float Trap Fixed Pivot Air Vent Valve Valve Ball Seat Linkage
- 22. 22 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Float and Thermostatic Float and Thermostatic Condensate enters Ball rises opening valve to full capacity Bellows cold; vent open to air and/or condensate flow Condensate flow decreases Ball moves downward; valve open less Valve modulates to balance outlet flow = inlet flow Steam enters; steam air mixture closes vent; temperature below saturation Start-Up Modulating Air Venting Air increases; temperature drops; vent opens Steam lost with air removal Dirt falls to bottom; may stop ball from dropping holding valve open; may plug valve
- 23. 23 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R F&T Traps F&T Traps Bellows Balance Pressure Thermodynamic Traps F&T Traps Modulation Poor Fair Good Backpressure Good Poor Good Dirt Fair Poor Poor Wear Fair Poor Good Water Hammer Poor Good Poor Freezing Good Good Poor
- 24. 24 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Inverted Bucket Inverted Bucket A. Bucket B. Valve on linkage • Sized for maximum flow at maximum pressure difference C. Air Vent D. Body • Material based on pressure and cost E. Inlet D C B A E Bottom inlet – Top outlet Other configurations available
- 25. 25 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R IB At Start-Up IB At Start-Up Low velocity flow • Condensate fills body • Condensate surrounds all internals; pressure same on all surfaces of all internals; no water hammer damage • Valve wide open for maximum flow rate; quick drain • Air pushed out ahead of condensate through wide open valve; quick vent • Small dirt particles suspended in flow and flushed through valve • Large dirt particles are too heavy to be carried to valve by low velocity flow around bucket lip, so they stay at bottom • No strainer needed in most applications Condensate Valve wide open
- 26. 26 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R IB Closed IB Closed • Start-up condensate accumulation gone • Steam enters depressing water level in bucket • When bucket approximately 2/3 full of steam, bucket becomes buoyant • Bucket floats valve to seat • Pressure difference pushes valve softly into seat • Valve seats tightly • Air passes through vent to collect at top of trap Condensate level Valve tightly closed
- 27. 27 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R IB Filling IB Filling • Valve closed; condensate continues to enter trap; no condensate back-up • Intermittent discharge but continuous drain • Water condenses and displaces steam; water level rises • Air continually rises through vent to top of trap • If air accumulation becomes excessive, air will depress water level and open valve Condensate Valve tightly closed Steam
- 28. 28 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R IB Opening IB Opening Small dirt flushed Valve wide open • Water level continues to rise • Bucket 2/3 full of water loses buoyancy; bucket falls pulling valve wide open • Air flushed out • Full capacity flow carries small dirt particles to wide open valve to flush each cycle • Pressure changes affect capacity only • Steam in trap continuously; condensate and air discharged at steam temperature • Cycle rate adjusts immediately with flow changes
- 29. 29 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R IB Thermic Vent IB Thermic Vent Bi-metal thermic vent • Open at start-up for quick vent of air under bucket • Closed at steam temperature; normal vent enough for operating air venting load
- 30. 30 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Inverted Bucket Inverted Bucket Bellows Balance Pressure Thermodynamic Traps F&T Traps Inverted Bucket Modulation Poor Fair Good Good Backpressure Good Poor Good Good Dirt Fair Poor Poor Good Wear Fair Poor Good Good Water Hammer Poor Good Poor Good Freezing Good Good Poor Good
- 31. 31 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R Armstrong Promise Armstrong Promise We provide intelligent system solutions that improve utility performance, lower energy consumption, and reduce environmental emissions . . . while providing an “enjoyable experience”! Intelligent System Solutions S T E A M • A I R • H O T W A T E R 31 “Expect many enjoyable experiences!” David M. Armstrong ®
- 32. 32 “Expect many enjoyable experiences!” David M. Armstrong ® Intelligent System Solutions S T E A M • A I R • H O T W A T E R
- 33. ©2008 Armstrong International, Inc.