The inability of a vacuum oil purifier to establish a vacuum properly (i.e., failure to draw a vacuum) is a common malfunction. This may be caused by a damaged seal, component failure, or improper operation. The following is a systematic troubleshooting guide and solutions:

Common Causes of Inadequate Vacuum in Oil Purifiers

1. Sealing System Leakage

- Symptoms: The vacuum gauge pointer fluctuates or fails to reach the standard vacuum level (e.g., above -0.095 MPa).

- Possible Leak Points:

✅ Deterioration or damage to the vacuum tank seal

✅ Loose pipe joints (especially the inlet and exhaust valves)

✅ Untightened inspection window/drain valve

✅ Worn vacuum pump oil seal

2. Vacuum Pump Malfunction

- Symptoms: Abnormal pump noise, heating, or no gas discharge from the exhaust port.

- Possible Causes:

✅ Insufficient or deteriorated vacuum pump oil (low oil level, emulsification, excessive impurities)

✅ Worn pump blades (resulting in reduced pumping efficiency)

✅ Damaged exhaust valve (unable to seal the exhaust passage)

3. Condensation System Problem

- Symptom: Heavy fog inside the vacuum tank, preventing condensation.

- Possible Causes:

✅ Condenser blockage (scale or oil contamination affecting heat transfer)

✅ Insufficient cooling water (flow rate/temperature not meeting specifications)

✅ Refrigeration unit malfunction (e.g., compressor failure)

4. Oil or operational issues

- Symptom: Large fluctuations in vacuum level, accompanied by oil splashing.

- Possible Causes:

✅ Excessive oil foaming (anti-foaming agent failure or oil degradation)

✅ Excessive oil intake (exceeds equipment processing capacity)

✅ Low oil temperature (high viscosity, difficulty releasing gas)

Oil Purifier Troubleshooting Steps

1. Initial Inspection

- Close all valves, start the vacuum pump, and observe the vacuum gauge:

- If the vacuum level still does not increase → Pump or seal problem

- If the vacuum level is normal but drops after startup → Pipeline or tank leak

2. Leakage Test

- Apply soapy water to joints, flanges, and other areas and observe for bubbles.

- Focus on inspecting the vacuum tank cover, drain valve, and oil level sight glass.

3. Vacuum Pump Inspection

- Check the oil level (should be between 1/2 and 2/3 of the way up the sight glass) and the oil quality (clear and free of emulsions).

- Listen to the operating sound: A sharp noise may indicate blade damage.

4. Condensation System Verification

- Check the temperature difference between the condenser inlet and outlet: A small temperature difference indicates insufficient heat exchange.

- Check the cooling water pressure (recommended 0.2-0.4 MPa).

Solutions

1. Sealing Issues

- ｒｅｐｌａｃｅ worn seals (material must be oil-resistant and heat-resistant).

- Tighten all pipe flange bolts using Teflon tape or sealant.

2. Vacuum Pump Repair

- ｒｅｐｌａｃｅ the vacuum pump oil (ISO VG68 oil is recommended).

- Disassemble the pump body and inspect the blades and valve plates. ｒｅｐｌａｃｅ any severely worn ones.

3. Condensation System Maintenance

- Clean the condenser scale (circulate a 5% citric acid solution).

- Ensure the cooling water temperature is ≤25°C and the flow rate meets equipment requirements.

4. Operational Adjustments

- Control the oil inlet rate (to avoid oil shock and foaming).

- Preheat the oil to 40-60°C (to reduce viscosity and facilitate degassing).

Oil Purifier Precautions

- Regular Maintenance: Check the seal monthly and ｒｅｐｌａｃｅ the vacuum pump oil every 500 hours.

- Oil Pretreatment: Allow high-water-content oil to settle and separate before entering the vacuum system.

- Record parameters such as vacuum level, temperature, and cooling water flow rate to facilitate fault tracing.

Summary

The core issues with a vacuum oil purifier failing to draw a vacuum are typically related to the seal, vacuum pump, and condensation. Troubleshooting in the order of "seal test → pump inspection → condensation verification" can quickly pinpoint the fault. If you are unable to resolve the issue yourself, contact the manufacturer's technical support to avoid damage to the equipment due to improper operation.