Armstrong automatic differential condensate controllers (DC) are designed to function on applications where condensate must be lifted from a drain point or in gravity drainage applications where increased velocity will aid in condensate drainage.
Lifting condensate from the drain point—often referred to as siphon drainage—reduces the pressure of the condensate, causing a portion of it to flash into steam. Since ordinary steam traps are unable to distinguish flash steam from live steam, they close and impeded drainage.
Increased velocity with gravity drainage will aid in drawing the condensate and air to the DC. An internal steam bypass controlled by a manual metering valve causes this increased velocity. Therefore, the condensate controller automatically vents the bypass or secondary steam. This steam is then collected for use in other heat exchangers or discharged to the condensate return line.
Capacity considerations for draining equipment vary greatly, according to the application. However, a single condensate controller provides sufficient capacity for most applications.
How they work
Condensate, air and steam (live and flash) enter through the controller inlet. At this point, flash steam and air are automatically separated from the condensate. Then they divert into the integral bypass at a controlled rate, forming secondary steam.
The valve is adjustable so it matches the amount of flash present under full capacity operation or to meet the velocity requirements of the system. The condensate discharges through a separate orifice by the inverted bucket.
Because of the dual-orifice design, there is a preset controlled pressure differential for the secondary steam system, while maximum pressure differential is available to discharge the condensate.
To review automatic differential condensate controllers by series, review the list below.