FunctionTissue drying and creping
Key partsCylinder shell / creping blade / steam & condensate
FocusGrinding, chattermark, thermal spray
1 · Equipment Overview
| Function | High-speed drying and creping of tissue. |
| Structure | Large cast-iron / steel cylinder with internal steam & condensate system. |
| Creping | Creping blade scrapes the surface to form the crepe structure. |
| Surface | Chrome-plated or chrome-free thermal-spray coating. |
| Key defects | Chattermark, grooving, spalling / erosion. |
2 · Maintenance Process
Cool-down & drainIsolate steam, cool and depressurize; drain condensate.
Surface surveyMagnified / lamp inspection of the shell; mark chattermark, grooving and erosion.
NDTUT/PT of shell and heads; verify wall thickness and cracks.
GrindingOn-line / in-place grinding to remove chatter and grooves and restore cylinder geometry.
Local build-upLocal thermal-spray build-up on eroded / pitted zones, then regrind.
Coating renewalRe-spray chrome-free coating where required.
Blade holder serviceClean creping-blade holders; reset blade angle and loading.
Condensate systemCheck siphons and steam traps; restore uniform temperature profile.
Trial runSpeed / temperature ramp-up; monitor vibration and crepe quality.
3 · Key Process Photos
4 · Acceptance & Handover
No chatter or grooving beyond limits after grinding; surface roughness to specification; NDT re-check of wall thickness and cracks passed; uniform creping after blade angle / load setting; vibration within limit at speed. Delivered with grinding records, NDT report and coating records. Safety: the Yankee is a pressure vessel — cool down, depressurize and verify zero-energy state before work; no open flame near the cylinder, residual fibre is a fire risk.