In the drawing below, there is a dotted line
indicating the level of the trigger level of the
trap. This is the height the condensate must
reach in the trap to start the discharge cycle.
When the balance line port is connected
back to the vessel or header pipe, as
shown in the drawing above, the trap is
filling by gravity. In these applications the
bottom of the vessel must be higher than
the top of the trap so that the condensate
flows by gravity down and out of the ves-
sel into the trap.
When the bottom of a vessel being
drained is lower than the trigger point in
the trap, as shown in the drawing to the
right, do not connect the balance line port
to the vessel or header pipe.
In the drawing to the right, if the balance
line were connected to the vessel or head-
er pipe, the condensate would be filling
the trap by gravity. With the bottom of the
vessel being lower than the top of the trap,
this would result in condensate backing up in
the vessel to the same height of the conden-
sate in the trap. When the condensate reached
the trigger level in the trap, shown by the dot-
ted line, the condensate would also reach the
same height in the vessel (the same dotted
line).
In an application where the bottom of the
vessel is lower than the top of the trap, the
balance line must be vented to atmos-
phere. Venting a small amount of air from
the trap reservoir to atmosphere results in
a pressure differential in the trap reser-
voir. This allows the pressure in the ves-
sel to push the condensate downward, out
of the vessel, and up into the trap. This
achieves proper filling of the trap while
removing all condensate from the vessel.
Send application questions to:
Technical Service
Phone: 865-970-9290
Fax: 865-977-6658
Page 12
022802 Model 1700-IG
INSTALLATION LOCATIONS
Method -1
Connect the balance line port to the vessel
producing the condensate.
This is the pref-
ered method since it is a closed-loop arrange-
ment. In the first four applications above, the
balance line is connected back to the vessel
that is producing the condensate. The pres-
sure on the incoming condensate to the trap
and the pressure in the balance line are the
same and the trap is filling by gravity. For this
method, the top of the trap must be below the
bottom of the vessel being drained.
Method -2
Connect the balance line port to the head-
er pipe leaving the vessel producing the
condensate.
This is an alternate method to
Method-1 when there is no convenient loca-
tion to connect the balance line to the vessel.
This is shown above in the drip leg applica-
tion. In the case of a dryer, however, connect-
ing the balance line to the header pipe leaving
the dryer essentially results in a bypass of the
dryer function. The condensate from the
dryer would have a path up the balance line
and back into the flow of dry air leaving the
dryer. That would not be desirable.
Method -3
Vent the balance line port to atmosphere
using a needle valve inserted in the balance
line port and slightly opened.
This can be
used on any application but must be used
when the bottom of the vessel is lower than
the top of the trap. The needle valve should
be opened slightly to a point where only a
small amount of air can be felt leaving the
needle valve. This method provides a pres-
sure differential in the trap reservoir and con-
densate is blown into the reservoir instead of
filling by gravity.
VESSELS WITH BOTTOM LOWER THAN THE TRAP’S TRIGGER LEVEL
THERE ARE THREE METHODS USED TO CONNECT THE BALANCE LINE PORT
1. Connect balance line to vessel being drained, to header leaving vesssel being drained, or vent to atmposphere - do not manifold balance lines together.
3. Bring control air from clean dry source downstream of dryer if possible, can manifold control air lines together.
2. Balance line balances reservoir of trap to vessel being drained. Control air operates air cyclinder. These two should not be connected together.
Control air from clean dry air
source if at all possible
For this
application
vent balance
line port to
atmosphere
Vessel like air receiver tank above with low vessel bottom
Trigger
level in
trap
