page 30 of 91 USB-QFLCII-14804/0
Locking lever
The locking lever is tightly connected to the flap blade by means of a shaft.
During
opening or closing, the locking lever rotates in clockwise direction.
System shutdown/
locking the unit During the closing process,
the
locking lever is “led” over the locking pin. If the
flap blade is closed completely, the locking pin snaps in by means of a spring
force. This prevents the flap blade from reopening in the event of an explosion.
Control of the locking device
Passive state:
•
Flap is closed
•
Electromagnetic unlocking dead-voltage
•
Flap locks mechanically
For system start-up, the locking device can be dis
engaged electromagnetically
.The
l
ocking
pin is pulled down by means of a magnet against the spring force and
released.
.
System
start‐up
unlocking
the unit
For system start-up, the locking unit's electromagnet releasing device, is activated for
an adjustable time (least amount of time as determined by your process) concurrently
with the start of the fan via the control system. With directly started fans, there is
enough vacuum immediately with the start to open the flap.
Note: With star delta start or with operation via a frequency converter, more time may
be necessary to build-up the vacuum. In that case, the adjustable time shall be
adapted corresponding to the start-up behavior during the system’s commissioning.
At the same time, the 24 VDC signal, which is switched to the electromagnetic
release, is supplied to two wire terminals in the terminal box (E 1 and E 2).
The locking pin is retracted and the locking lever is released. The air flow, created by
the fan now opens the flap blade.
At the end of the adjusted time (T=2 seconds) for the electromagnetic release, the two
wire terminals E1 and E2 become dead-voltage (0 – signal). This assures that the
dead-voltage locking mechanism leads to the locking of the flap blade in the event of
an explosion.
pin
Locking lever
To Next Page
Loading...
