Rotating Dryers That Require Syphon Drainage - Trap

The best traps for syphon-drained rotating dryers:

continuously drain the steam space
conserve energy over a long service life
purge the system of condensables and non-condensables
respond rapidly and efficiently to slugs of condensate
handle dirt well
remove flash steam efficiently

These requirements combine to make the differential condensate controller the best trap for syphon-drained rotary dryers. An inverted bucket (IB) steam trap with a large vent may be a suitable alternative provided proper sizing procedures are followed.

	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