Steam Traps selection and advantages vs. disadvantages of each type

There are many factors that affect steam generating system in the energy industry, and multiple pros and cons in selecting a right steam trap for your application, the following are advantages vs. disadvantages of each type of steam trap to consider when selecting one for your project.

	Advantages	Disadvantages
Disc Steam Traps	• Failure mode. gradually, predictably open over time. • Simple construction. • Small size and light weight. • Can be mounted in any position. • Rugged. withstands water hammer. • Self draining, not damaged by freezing. • Function not impaired by superheat. • Versatile, suitable for wide pressure range. • Condensate discharge temperature closely follows the saturation curve. • Performance is easily checked in field.	• Marginal air handling capability. • Excessive backpressure in return systems can prevent trap from closing. • Life is reduced significantly as pressures move above 300 psi. • High discharge noise level. • Dirt particles can increase cycle rate causing wear.
Piston Steam Traps	• Suitable for high pressure • Can be mounted in any position. • Good response to changing condensate load conditions. • Rugged, withstands water hammer. • Self-draining, not damaged by freezing. • Function not impaired by superheat. • Good air handling capability. • Primary failure mode-open. • Small size and light weight.	• Excessive backpressure in return systems can prevent trap from closing. • Condensate discharge temperature follows the saturation curve over a limited range. • Difficult to field check because of continuous control flow discharge.
Lever Steam Traps	• Suitable for high pressure applications. • Good response to changing condensate load conditions. • Rugged, withstands water hammer.  • Not damaged by freezing. • Function not impaired by superheat.  • Good air handling capability. • Small, compact, easy to install and service.	• Excessive back pressure in return systems can prevent trap from closing. • Difficult to field check due to continuous control flow discharge. • Can only be mounted in one position.
Closed Float Steam Traps	• Unaffected by sudden or wide pressure changes. • Responds very quickly to condensate load changes. • Continuous discharge. • Condensate discharge temperature closely follows the saturation curve. • Function is not impaired by high back pressures. • Energy efficient. • Simple construction.	• Relatively large and heavy. • Float easily damaged by water hammer. • Does not withstand freezing. • Can be mounted only in one position. • Suitable only for relatively low pressures. • Requires auxiliary air vent which is an additional source of failure. • Primary failure mode is closed. • Not self draining.
Inverted Bucket Steam Traps	• Simple construction. • Rugged. • Condensate discharge temperature closely follows the saturation curve. • Reliable.	• Marginal air handling during start-up. • Not self draining; subject to freeze ups. • Not suitable when superheat is present. • Can lose prime. and is not self-priming. • Can be mounted only in a single position. • Failure mode is unpredictable (open or closed).
Open Bucket Steam Traps	• Simple construction. • Reliable. • Condensate discharge temperature closely follows the saturation curve. • Function not impaired by high back pressure. • Fast response to changing condensate loads.	• Not self draining; subject to freeze ups. • Not suitable when superheat is present. • Can lose prime, not self-priming. • Can be mounted only in a single position. • Requires auxiliary air vent which is an additional source of failure. • Suitable only for relatively low pressures. • Relatively large and heavy.
Bimetallic Steam Trap	• Rugged. • Energy efficient. • Self draining. • Resistant to freeze damage. • Withstands water hammer. • Capable of discharge temperature adjustment. • Can be mounted in several positions. • Primary failure mode-open.	• Dirt particles can prevent tight valve closing. • Condensate discharge temperatures do not follow the saturation curve closely. • Difficult to field check when operating in a throttling mode. • Condensate discharge temperature is made lower as backpressure increases. • Relatively slow response to changing condensate loads. • Bimetallic elements are relatively susceptible to corrosion.
Bellows Steam Traps	• Excellent air handling capability. • Energy efficient. • Self draining. • Various condensate discharge temperatures available depending on bellows design. • Condensate discharge temperature follows the saturation curve. • Can be mounted in several positions. • Simple construction. • Small size and weight.	• Bellows elements tend to be failure prone, especially when subjected to water hammer. • Difficult to field check when operating in a throttling mode. • Generally not suited for high pressure applications. • Limited superheat capability. • Short stroke diaphragm design susceptible to dirt initiated failures.
Liquid or Solid Expansion Steam Traps (Wax Capsule Steam Trap)	• Rugged. • Good air handling capability. • Resistant to freeze damage. • Withstands water hammer. • Can be mounted in any position. • Self draining. • Primary failure mode is open.	• Dirt particles can prevent tight close. • Requires substantial sub-cooling. • Difficult to field check. • Slow response to changing condensate loads. • Actuator damaged by exposure to high temperature.
Orifice Steam Traps	• No moving parts. • Suitable for high pressure application. • Rugged, withstands water hammer. • Not damaged by freezing. • Function not impaired by superheat. • Can be mounted in any position.	• Orifice size must be carefully selected for each installation. • Can not respond to varying condensate loads. • Inefficient if oversized. • Dirt particles readily impair performance. • Difficult to field check because of continuous discharge. • In the absence of condensate, the trap passes live steam.