Maintenance of the vacuum oil filter when it is out of service is essential to extend the life of the equipment and ensure stable performance the next time it is used. The following are specific maintenance steps:

1. Clean the equipment
- External cleaning: Thoroughly clean the surface of the equipment to remove oil and dust.
- Internal cleaning: Drain the oil circuit and oil tank, clean the filter element, filter screen, and oil pipe.

2. Drain the oil
- Drain the oil tank: Completely drain the oil in the oil tank to prevent the residual oil from deteriorating.
- Clean the oil circuit: Drain the oil in the oil circuit to ensure that there is no residue.

3. Check the filter element and filter screen
- Replace the filter element: If the filter element has reached the replacement cycle, replace it in time.
- Clean the filter screen: Thoroughly clean the filter screen to ensure that there is no blockage.

4. Check the seals
- Check the seals: Check all seals and replace them in time if they are aged or damaged.
- Apply lubricant: Apply an appropriate amount of lubricant on the seals to prevent cracking.

5. Check the electrical system
- Disconnect the power supply: Make sure the equipment is completely powered off.
- Check the wiring: Check the electrical wiring to ensure that there is no looseness or corrosion.
- Protect electrical components: Use dust covers to protect electrical components.

6. Lubricate moving parts
- Lubricate parts: Lubricate moving parts such as pumps and motors to prevent rust.
- Check wear: Check the wear of moving parts and replace them if necessary.

7. Rust prevention
- Apply anti-rust oil: Apply anti-rust oil on metal surfaces to prevent rust.
- Cover protection: Cover the equipment with a dust cover or plastic sheet to prevent dust and moisture from intruding.

8. Environmental control
- Dry environment: Store the equipment in a dry and well-ventilated environment.
- Temperature control: Avoid exposing the equipment to extreme temperatures.

9. Record maintenance
- Maintenance records: Record maintenance in detail, including replaced parts, lubricated parts, etc.
- Next maintenance plan: Make a next maintenance plan to ensure regular maintenance.

10. Regular inspection
- Regular inspection: Even if the equipment is out of service, the equipment status should be checked regularly to ensure that there are no abnormalities.
- Trial run: Before reactivating after a long period of outage, a trial run should be carried out to ensure that the equipment is normal.

11. Spare parts management
- Spare parts reserve: Reserve common spare parts, such as filter elements, seals, etc., to ensure timely replacement.
- Spare parts inspection: Regularly check the status of spare parts to ensure that they are intact.

The above maintenance measures can ensure that the vacuum oil filter is in good condition during the outage period, extend the service life of the equipment, and quickly resume normal operation when it is used next time.