Can Vacuum Oil Purifiers Filter Heavy Lubricating Oils?

Vacuum oil purifiers can treat heavy lubricating oils, but only with specialized high-temperature systems. Standard vacuum purifiers usually fail due to viscosity, heating limits, and vacuum pump contamination.

Why Standard Vacuum Oil Purifiers Struggle with Heavy Oils

1. Extremely High Viscosity

Heavy oils (gear oil, cylinder oil, residual oils) often exceed hundreds or thousands of cSt.

Issues:

Poor spreading/atomization inside the vacuum chamber

Limited oil–gas contact area → weak dehydration

Difficult pumping and high flow resistance

2. Need for Very High Heating Temperatures

Conventional units heat to 60–80°C. Heavy oils require 90–120°C.

Risks:

Accelerated oxidation and sludge

Approaching flash point → safety hazards

Seal aging at high temperatures

3. Vacuum Pump Contamination

Heavy oil vapors enter the vacuum pump, causing:

Pump oil emulsification

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Pump damage

4. Filter Clogging

Asphaltenes, gums, and sludge dissolve when hot but reprecipitate in filters, blocking elements quickly.

What Type of Oil Purifier Can Handle Heavy Lubricating Oil?

1. High-Power Heating

Uniform, stable heating up to 90–120°C, at least 20–30°C below the flash point.

2. Thin-Film or Forced-Film Vacuum Separator

Using rotors or scrapers to create a thin oil layer and increase evaporation surface—far more effective than standard atomization.

3. Heavy-Duty Vacuum System

Prefer:

Pumps with condensers/wash tanks

Dry vacuum pumps resistant to oil vapor

4. High-Viscosity Oil Pumps

Gear pumps or screw pumps to ensure stable transfer at high viscosity.

5. Low-Restriction Filtration

Metal mesh or large glass-fiber elements, optional backwash, to reduce clogging.

6. Full Safety Controls

Temperature, pressure, vacuum, liquid-level interlocks.

Practical Recommendations

Conventional Vacuum Purifiers

❌ Not suitable for untreated heavy oils—poor results and high risk.

High-Temperature Thin-Film Vacuum Purifiers

✔ Effective for deep dehydration/degassing but costs more and requires careful temperature control.

Best Solution by Contaminant Type

Lubricant grade and viscosity

Main contaminants (water, gas, sludge, particles)

Required treatment depth

Operating temperature and safety limits