TL;DR
A plunger seal leak contaminates the seal area with product and can allow sanitation chemical ingress. Replace the seal and inspect the plunger surface before restarting.
What you might see
- product dripping from plunger seal area
- seal flush return showing product contamination
- pressure fluctuation on homogenizing gauge
- visible wear marks on plunger surface
Likely causes
Seal lip wear from abrasive or highly viscous product
Plunger surface scoring from a foreign particle
Seal material incompatibility with CIP chemical concentration
Plunger misalignment from worn crosshead bearing
Required tools
- LOTO kit
- Torque wrench
- Replacement plunger seal (food-grade certified)
- Surface profilometer (optional)
Safety first
- Homogenizer pump block pressure can reach 350 bar. Confirm all pressure is zero before opening any plunger seal assembly.
- Product contact seal materials must be food-grade certified. Do not substitute a non-food-grade material without an engineering change order.
- Clean and sanitize the plunger area after maintenance before returning to production.
Procedure
- 1
Stop the homogenizer and lock out the main drive and hydraulic pressure.
Warning: The homogenizer operates at extremely high pressure. Confirm all pressure is relieved before disassembling any plunger or seal assembly. - 2
Depressurize the pump block and drain the product passage.[1]
- 3
Remove the plunger and inspect the plunger surface for scoring or roughness. Polish marks can be assessed with a profilometer.[1]
- 4
Remove the seal ring and retainer. Inspect for wear, compression set, or chemical damage.
- 5
Install a new seal of the correct food-grade material. Ensure the retainer is torqued to specification.
- 6
Check the crosshead bearing for play. Replace if free play exceeds the tolerance.
- 7
After reassembly, run the homogenizer at reduced pressure for 5 minutes and inspect for leaks before restoring full operating pressure.
Sources
GEA Ariete GEA Ariete NS3037 / NS3075 Homogenizer general technical documentation, GEA Ariete
GEA Ariete NS3037 / NS3075 homogenizer general plunger and seal maintenance procedures (general)
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