Can’t the vacuum level of the muffle furnace be increased?

When the muffle furnace is vacuumed, the vacuum degree cannot be increased, which may be caused by poor sealing, insufficient vacuum pump performance, furnace material or process problems, improper operation or maintenance. The following are specific reasons and solutions:

1. Sealing issue
Aging or damage of sealing ring: The sealing ring is a key component to ensure the vacuum degree of the muffle furnace. After prolonged use, the sealing ring may age, deform, or be damaged, leading to air leakage. At this point, replace the sealing ring with a new one and apply vacuum silicone grease to improve the sealing performance.
Improper installation of flange interface: The flange interface is an important part for connecting various components of the muffle furnace. If installed improperly, such as not tightening bolts or uneven sealing surfaces, it can also cause air leakage. At this point, the flange interface should be reinstalled to ensure that the sealing surface is flat and the bolts are tightened.
Cracks or holes in the furnace body: Cracks or holes may occur in the furnace body during manufacturing or use, leading to gas leakage. At this time, the furnace body should be carefully inspected, and if cracks or holes are found, the furnace body should be repaired or replaced.

2. Performance issues with vacuum pumps
Vacuum pump aging or damage: The vacuum pump is the core component for vacuuming. If the vacuum pump ages or is damaged, its pumping capacity will decrease, resulting in an inability to increase the vacuum level. At this time, a new vacuum pump should be replaced or the vacuum pump should be repaired.
Vacuum pump oil contamination or insufficient: Vacuum pump oil plays a lubricating and sealing role during the vacuum pumping process. If the vacuum pump oil is contaminated or insufficient, it will affect the performance of the vacuum pump. At this point, it is necessary to replace the vacuum pump oil with a new one and ensure that the oil level is sufficient.

3. Furnace material or process issues
High gas release rate of furnace body materials: Some furnace body materials (such as porous materials) may release gas at high temperatures, leading to a decrease in vacuum degree. At this time, materials with low gas release rates (such as stainless steel, ceramics, etc.) should be selected to manufacture the furnace body.
There may be volatile impurities in the furnace, such as dust, oil stains, etc., which evaporate at high temperatures and contaminate the vacuum environment. At this time, the furnace should be thoroughly cleaned to ensure no impurities remain.

4. Operation or maintenance issues
Not following the operating procedures for vacuuming: During the vacuuming process, certain operating procedures need to be followed, such as starting the mechanical pump for rough vacuuming first, and then starting the diffusion pump for fine vacuuming. If operated improperly, it may cause the vacuum degree to not increase. At this time, the vacuuming operation should be strictly carried out according to the operating procedures.
Insufficient equipment maintenance: Failure to maintain the muffle furnace for a long time may lead to a decrease in equipment performance, including issues such as inability to increase the vacuum level. At this time, regular maintenance should be carried out on the muffle furnace, such as replacing the sealing ring, cleaning the furnace, and checking the performance of the vacuum pump.