Operating the Device
21
3.11 Maintenance
Fig. 4: Sealing ring on the siphon
The sudden temperature differences when filling the dewar with liquid nitorgen can result in
wear or signs of aging on the sealing ring (
KD
) .
• The sealing ring (
KD
) must be replaced if you notice nitrogen escaping in the
area of the
tension lock (
KS
).
NOTICE
Increased frost formation on the tension lock (
KS
) can already indicate damage to the sealing
ring (
KD
).
CAUTION
Always discharge pressure before replacing the sealing ring.
• Close the pressure build-up valve (
V2
).
• Carefully open the vent valve (
V3
).
It is impermissible to use the following agents and tools:
• pliers
• striking tools
• lubricating spray
• hemp
• open flame
• steam
• leak detection spray
• suds
Only the bubble method outlined below may be used to test that the safety valve is securely in
place and has the correct response pressure. This prevents the valve mechanics becoming
dirty and rusty . The response pressure is marked on the safety valve.
KS
KD
KH
