The PMO (maximum operating pressure) rating of model selected must meet or exceed the maximum steam pressure or the trap may no
t
open. For example; the FTE-125 has a PMO of 125 psi. Condensate capacity (lbs/hr) of the trap is based on the differential pres
sure across
the trap. The condensate loads (lbs/hr) for process applications are normally calculated at the maximum steam pressure; then an
appropriate
safety margin is applied in order to select a trap with sufficient capacity when operating at lower steam pressures. Reference
full explanation of
Safety Load Factors in Steam Traps Introduction section.
When a temperature control valve is regulating flow to the process equipment, it is recommended to select a trap with a PMO that will
exceed the inlet steam pressure to the control valve.
For Example:
Process application has a maximum steam inlet pressure of 100 psi, a maximum condensate load of 10,000 lbs/hr and is
discharging to a condensate return line with a possible back pressure of 25 psig.
Δ
P
= 100-25 = 75 PSI
To select trap
:
If the Safety Load Factor is chosen to be 2X max capacity at max differential pressure, then Trap should be selected based on
20,000 lbs/hr (10,000 x 2 = 20,000) at 75 PSI differential pressure with a PMO in excess of 100 PSIG
Selection
:
FTE-200-17-N
, PMO=200 PSIG,
2”
NPT with a condensate capacity of 21,500 lbs/hr at 75 PSI differential pressure.
