Differential Condensate Controller

Differential Condensate Controller Operating Principles

Automatic differential condensate controllers are designed for applications where condensate must be lifted from a drain point or applications that use gravity drainage and require increased velocity to aid in their operation.

Lifting condensate from the drain point reduces the pressure of condensate, causing a part of it to flash into steam. Since ordinary steam traps cannot distinguish flash steam from live steam, they close and impede drainage.

Increased velocity with gravity drainage aids in drawing condensate and air to the differential condensate controller, where it vents the secondary steam. Secondary steam is then collected for use in other heat exchangers or discharged to the condensate return line.

Drainage equipment capacity varies a great deal depending on the application. A single condensate controller provides sufficient capacity for most applications.

How It Works

Differential controllers are constructed similarly to inverted bucket steam traps. The difference is that DCs have a secondary outlet tube mounted coaxially in the inlet tube under the bucket. At the top of the secondary outlet tube is an umbrella-shaped guard that prevents inlet steam, air or condensate from flowing directly into the secondary outlet. Condensate is discharged from the primary orifice at the maximum pressure differential, the same as in an IB trap. A manual metering valve located in the secondary steam outlet piping sets the pressure differential under the bucket. It is adjusted to match the pressure reduction created in lifting the condensate. In this manner, the flash steam, as well as any non-condensables, will be evacuated through the secondary outlet.

Armstrong DC Features

	1.	Low-pressure air venting. Continuous drainer.
	2.	Resistant to wear and corrosion. Bucket and linkage are stainless steel and free-floating.
	3.	Self-lapping stainless steel valve. Valve does not pass live steam.
	4.	Back pressure reduces capacity.
	5.	Resistant to water hammer and freezing damage.
	6.	Removes small dirt particles.
	7.	Few moving parts means long service life.
	8.	Manual metering valve required to adjust secondary steam output. Secondary orifice provides continuous air venting. Handles heavy start-up loads. Constant, controlled flow provides scrubbing effect.

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