How to replace a glass disc: what to measure and which documents are needed
A step-by-step replacement procedure: measurements, material selection, documents, safety.
Short answer
Replacement starts with measurements and documentation, not with a purchase: the outer diameter, thickness, material, edge profile and operating conditions define the correct disc.
Never install discs of unconfirmed origin: glass under pressure is a structural part of the vessel.
Step-by-step procedure
- stop and cool the vessel; release the pressure and confirm the medium is drained;
- collect the shards and keep the fragments: the diameter and thickness are restored from them;
- measure the outer diameter, thickness and edge profile (chamfer or rounding);
- record the material from the fitting marking or the vessel certificate;
- check the condition of the seats and gaskets — replace both gaskets;
- order a disc with a confirmed standard (for example DIN 7080) and matching dimensions.
Documents
A useful pack: the fitting marking, the vessel certificate, previous glass certificates, photos of the fitting and its parts. These data enter the RFQ sheet and reduce the risk of re-ordering the “wrong” disc.
Safety
Glass under pressure can have sharp edges and residual stresses after failure. Never return a vessel to service with temporary plugs instead of glass.