Maintenance; Disconnecting The Electronics; Cleaning The Antenna - Siemens sitrans LR 400 Instruction Manual

Maintenance

Disconnecting the Electronics

For maintenance, it is possible to separate the electronic enclosure of the device from the
mechanical part (process flange) without endangering the pressure tightness of the
vessel. Release the threaded ring of the electronics part from the mechanical part with a
hook key 68/75 and remove the electronics part. Place the enclosed plastic cap on the
mechanical part to prevent soiling.

Cleaning the Antenna

Depending on the type of measuring material, it may be necessary to clean the antenna
at certain intervals to remove soiling which could affect the measuring result. You can
clean it without removing the flange from the vessel.
1. Disconnect and remove the electronics part as described above.
Warning!
As soon as you remove the pressure window from the mechanical part
the vessel is no longer pressure-tight and explosion protected!
2. Remove the threaded ring with an M36 open-ended wrench, unscrew the pressure
window and lift it off the mechanical part together with the white PTFE stopper.
3. Clean the inside of the antenna with compressed air and/or a brush. Make sure that
the pressure window thread is clean. Apply fresh grease to the thread as required.
Check the O-rings for damage and replace them if necessary.
4. If the PTFE stopper has come loose when removing from the pressure window,
reinsert it long end first into the mechanical part. Push it into the guide up to its
thickened stop.
5. Replace the pressure window and tighten it.
6. Reattach the electronics part to the mechanical part. Rotate the housing head to
align it, before tightening the threaded ring.
7. Check the pressure tightness of the vessel.
WARNINGS:
• Never attempt to loosen, remove, or disassemble process connection or
instrument housing with vessel contents.
• Improper installation may result in loss of process pressure.
For more frequent cleaning, apurging system installed between the flange and the horn
antenna is an option. The system provides an inlet on the flange where cooling air or
cleaning fluid passes through the flange and exits the inside of the horn to clean it. The
customer will supply the purging medium by manual or automatic valve system. This
option is only available with universal flanges.
Note: The glass pressure window is available on Zone 0 / Zone 20 ATEX versions. It is
located under the threaded collar of the antenna and protects the electronics from
conditions within the tank.
7ML19985FH03 SITRANS LR 400 – INSTRUCTION MANUAL Page 69