What is the reason why the vacuum degree of the vacuum muffle furnace cannot be increased?

The reasons why the vacuum degree of the vacuum muffle furnace cannot be increased may include the following aspects:

Vacuum system leakage:
Reason: Poor container sealing, loose pipeline connections, leakage of electromagnetic valves, pipe joints, vacuum pump suction valves, and sealing gaskets around the working chamber.
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.

Vacuum pump issue:
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. In addition, pump oil pollution, insufficient or too thin, poor or damaged operation of the vacuum pump, overheating of the pump leading to insufficient expansion clearance of the components may also affect the vacuum degree.
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.

Gas release from furnace lining materials:
Reason: The lining material will release gas at high temperatures, leading to a decrease in vacuum degree.
Solution: Eliminate the gas released from the furnace lining material by extending the pumping time or increasing the pumping rate of the vacuum pump.

Control system malfunction:
Reason: Failure of vacuum gauge or vacuum valve control, etc.
Solution: Inspect the control system, repair or replace damaged components.

Other factors:
The O-ring of the suction valve has come off, causing the vacuum pump to be unable to effectively suction air. The solution is to unplug the vacuum tube from the pump nozzle, remove the suction nozzle, take out the compression spring and suction valve, gently stretch the O-ring several times, re insert it into the groove, and then install it.
Oil return valve blockage: affecting the normal operation of the vacuum pump. The solution is to remove the return valve for cleaning.