Flash Tanks - Trap

The best traps for this flash tank application:

continuously drain
conserve energy over a long service life
resist damage due to hydraulic shock
vent air and CO₂ at steam temperature
operate against a back pressure
perform well on very light loads
respond quickly and efficiently to slugs of condensate

The trap type that best suits all of these requirements is generally an inverted bucket (IB) trap with a large vent. The differential condensate controller is preferred where condensate loads exceed the separating capability of the flash tank. An alternative selection would be a float and thermostatic (F&T) trap.

	Characteristic	Inverted Bucket	F&T	Disc	Thermostatic	Differential Controller
A	Method of Operation	Intermittent	Continuous	Intermittent	Intermittent	Continuous
B	Energy Conservation (Time in Service)	Excellent	Good	Poor	Fair	Excellent
C	Resists Wear	Excellent	Good	Poor	Fair	Excellent
D	Resists Corrosion	Excellent	Good	Excellent	Good	Excellent
E	Resists Hydraulic Shock	Excellent	Poor	Excellent	Poor	Excellent
F	Vents Air and CO₂ at Steam Temperature	Yes	No	No	No	Yes
G	Vents Air at Very Low Pressure (1/4 psig)(.02 bar)	Poor	Excellent	NR	Good	Excellent
H	Handles Start-up Air Loads	Fair	Excellent	Poor	Excellent	Excellent
I	Operates Against Back Pressure	Excellent	Excellent	Poor	Excellent	Excellent
J	Resists Damage from Freezing	Good	Poor	Good	Good	Good
K	Can Purge System	Excellent	Fair	Excellent	Good	Excellent
L	Performs on Very Light Loads	Excellent	Excellent	Poor	Excellent	Excellent
M	Responds to Slugs of Condensate	Immediate	Immediate	Delayed	Delayed	Immediate
N	Handles Dirt	Excellent	Poor	Poor	Fair	Excellent
O	Comparative Physical Size	Large	Large	Small	Small	Large
P	Handles "Flash Steam"	Fair	Poor	Poor	Poor	Excellent
Q	Mechanical Failure (Open -- Closed)	Open	Closed	Open	Open, Closed	Open


First Choice				Alternative				Overriding condition