The vacuum degree of graphite high-temperature vacuum furnace cannot be pulled up

05-23-2025       Author: KJ technology

The inability to increase the vacuum degree of graphite high-temperature vacuum furnace may be caused by various reasons. The following is a specific analysis and solution:

1. The problem of vacuum unit pumping capacity

Vacuum pump malfunction:

Reasons: pump oil pollution, insufficient or too thin, poor or damaged vacuum pump operation, pump overheating, mechanical expansion leading to small gaps, improper cleaning causing debris to enter the oil, etc.

Solution: Clean the vacuum pump, replace with new vacuum pump oil, replace with a new pump, strengthen the cooling of the pump, check if the power supply is normal, repair or replace damaged vacuum pump parts.

Insufficient pumping capacity:

Reason: The mechanical pump has a low pumping rate or low vacuum degree, the Roots pump has a low pumping rate or low vacuum degree, and the K-type high vacuum oil diffusion pump has a low pumping rate.

Solution: Check the working condition of the vacuum pump and repair or replace it according to the specific situation.

2. Leakage issue

External leakage:

Reasons: aging, corrosion or damage of seals, loose connections at pipeline joints, air leakage of solenoid valves, pipe joints, vacuum pump suction valves and sealing gaskets around the working chamber, etc.

Solution: Check and replace aging or broken seals to ensure good sealing; Check the pipeline connections, solenoid valves, pipe joints, etc., and repair or replace them. The flame method can be used to gradually search for leaks near suspicious points by utilizing the principle that airflow can deflect flames.

Internal leakage:

Reason: Internal leakage often occurs on equipment with water cooling points, such as significantly low pumping speed of mechanical pumps, low vacuum gauge readings, rapid emulsification of mechanical pump oil, and obvious corrosion of iron-based components in the vacuum chamber.

Solution: First clean the cavity, then add cooling water and carefully check if there are any wet spots in the water pipeline. Wet spots are the leakage points. Internal leakage needs to be investigated from different vacuum working areas of the vacuum furnace.

3. Other possible reasons

Furnace or workpiece contamination:

Reason: Oil stains, impurities, etc. on the surface of the furnace body or workpiece may cause a decrease in vacuum degree.

Solution: Clean the furnace body and workpiece to ensure a clean and pollution-free surface.

Control system issues:

Reasons: such as damaged or improperly set temperature controllers, broken or short circuited thermocouple wires, temperature control instrument malfunctions, etc.

Solution: Check and adjust the settings of the thermostat, replace or reconnect the thermocouple, and repair the control system.

Cooling system issues:

Reason: Insufficient cooling water supply, blocked cooling system, etc.

Solution: Check if the cooling water pipeline is unobstructed, ensure sufficient cooling water supply, and clean any blockages.