Maintain the machine lubrication system for troublefree operation

Proper maintenance of your machine's lubrication system is critical for safe and troublefree operation of equipment. This week, we review the proper flushing, startup and shutdown processes for your lubrication system.

For a complete description of the various lubrication units, see the vendor's information included in your machine maintenance manual.

Flushing

At the initial start-up and after any major maintenance work the piping should be flushed to bring any contaminants in the pipes back to the tank.

Before flushing:

• Bypass the oil cooler
• The flushing oil must be suitable for the lubrication oil selected. The supplier of the lubricating oil used by the mill should specify the flushing oil. If this information is not available, flushing can be carried out with pure base oil ISO VG68.

Startup

Follow these steps when starting up the machine:

• Make sure that the lube unit and sump tanks are clean.
• Check that the sump tanks are ready for operation.
• Check that the oil temperature is high enough. The recommended minimum temperature is typically at least 120°F.
• Check that the shut-off valves at the main pumps are open.
• The filter elements should be clean.
• Start the lubrication pump.
• Monitor the pressure and temperature.
• Check that the temperature of the oil reaches the recommended temperature.
• Once stable operating conditions have been obtained, check that the oil flow in all flow meters is sufficient.
• For a more complete, detailed description, see the lube unit vendor's information included in your machine's maintenance manual.

Shutdown

Follow these steps when shutting down the machine:

• Stop the lubrication unit from the DCS.
• Check that the oil heating of the tank is kept on.
• Keep the lube sump units ready for operation at least one minute after the main pump unit has been stopped.

Lubricating oil

The lubrication oil must effectively resist mixing with air (foaming) and water (emulsion) and it must not stratify at all temperature ranges. The viscosity index of the oil should be at least 95 and conform to the ISO VG viscosity classification.

The fluid must have rust inhibitors to prevent oxidation and not tend to change color during long service runs. The fluid must have excellent lubrication properties.

The lubricating system has been designed for mineral oils, type ISO VG220.

For more information on maintenance of your lubrication systems, contact your Valmet representative. Paper Machine Maintenance School covers lubrication systems in detail.