Measurement

Undamaged, flat, and properly cleaned sealing surfaces are the basic prerequisite for a permanently leak-tight flange connection. An on-site inspection during operation can already provide initial indications of possible causes based on the leakage pattern.

Subsequent on-site measurement of the flange sealing surfaces enables further conclusions regarding potential leakage causes. For small sealing surfaces or grooves, measurements can be carried out using mechanical tools; for large sealing surfaces, laser-optical measurement is recommended.

Laser-optical measurement can be performed with approximately 20 measuring points per sealing surface, including computer analysis, within about 1–2 hours.

Evaluation

The evaluation of sealing surface measurements can either demonstrate the suitability of the sealing surface or determine the required amount of reworking.

A measurement report typically provides the following data:

• Distance of the measuring points from a mean reference plane
• Unacceptable deviations
• For grooves: groove depth and transitions
• For lands/ridges: land height and transitions

This enables clear conclusions to be drawn about the condition of each sealing surface. The maximum measurement diameter is approx. 20 m, and the accuracy—given exact placement of the data sensor—is 0.001 mm.