|Advantages of the liquid expansion steam trap:
Liquid expansion traps can be adjusted to discharge at
low temperatures, giving an excellent 'cold drain' facility.
Like the balanced pressure trap, the liquid expansion trap
is fully open when cold, giving good air discharge and maximum
condensate capacity on 'start-up' loads.
The liquid expansion trap can be used as a start-up drain
trap on low pressure superheated steam mains where a long
cooling leg is guaranteed to flood with cooler condensate.
It is able to withstand vibration and waterhammer conditions.
Disadvantages of the liquid expansion steam trap:
The flexible tubing of the element can be destroyed by
corrosive condensate or superheat.
Since the liquid expansion trap discharges condensate at
a temperature of 100°C or below, it should never be
used on applications which demand immediate removal of condensate
from the steam space.
If the trap is to be subjected to freezing conditions the
trap and its associated pipework must be well insulated.
The liquid expansion trap is not normally a trapping solution
on its own, as it usually requires another steam trap to
operate in parallel. However, it can often be used where
start-up rate is not an important consideration, such as
when draining small tank heating coils.