STEAM TRAP APPLICATIONS PROCESS TRAP GUIDELINES – Syphon Drainage
PURPOSE:
For removing condensate from steam heat transfer equipment when the steam trap is to be installed above the point where condensate will collect.
OPERATION:
When steam is used to heat liquid in a tank with a submerged coil or a rotary drum dryer, gravity drainage to the steam trap is not possible. For these applications, it is necessary to install the steam trap above the drain point of the equipment by creating a syphon lift to allow for proper condensate drainage.
INSTALLATION GUIDELINES:
(see Figure 3)
• There are two critical requirements to ensure proper operation of syphon lift process drainage systems: A water seal lift fitting and a steam trap with a function to prevent steam lock (often referred to as Steam Lock Release or SLR). • The lift fitting on a submerged coil provides a water seal to stop steam from pushing past the condensate and reaching the steam trap, preventing a vapor-lock condition of the trap. • Steam Lock Release (SLR) is provided on the steam trap to ensure the syphon lift remains continuous by preventing steam from becoming trapped – or locked – between the cavity of the steam trap and incoming condensate. The SLR function allows any small portion of trapped steam to be automatically removed from the system, allowing continuous drainage. • Consider low-cracking pressure (1/4 PSI opening pressure) check valves after steam traps when discharging into condensate return lines. Check valves eliminate the possibility of condensate backing up through the steam trap into the system. • An isolation valve and strainer should be installed before any steam trap. The isolation valve simplifies maintenance of the trap and the strainer protects the trap from any dirt, debris or scale in the line.
SUBMERGED COIL FOR HEATING LIQUID
Figure 3:
Steam Lock Release Mechanism must be used when trap is positioned above condensate level.
WT3001 Thermostatic Trap with Steam Lock Release
Isolation Valve
STEAM
To Atmosphere or Condensate Return Line
Water Seal Lift Fitting
88
www.watsonmcdaniel.com •• Pottstown PA • USA • Tel: 610-495-5131
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