vacuum atmosphere furnaceThe sealing performance of the furnace directly affects the purity of the atmosphere, the stability of the vacuum degree, and the safety of experiments or production. The following are simple and easy to operate inspection methods that can be completed without complex tools:
1、 Static vacuum holding method (most commonly used)
preparation
Close the vacuum atmosphere furnace door, tighten all sealing and clamping bolts, and ensure that the furnace door sealing strip is wrinkle free and undamaged.
Vacuum pumping operation
Start the vacuum pump and pump the furnace to the standard vacuum level specified by the equipment (such as 10 ⁻¹~10 ⁻³ Pa, please refer to the instrument manual for details). After reaching the target vacuum level, close the vacuum pump and vacuum valve, and record the initial vacuum level value and time.
Pressure observation
Let it stand and maintain pressure for 30-60 minutes, observe the changes in the vacuum gauge reading:
If the decrease in vacuum degree is ≤ 5%, it indicates good sealing performance;
If the vacuum degree drops rapidly, it indicates the presence of a leak point.
Leakage point location
Prepare soapy water, dip a brush in soapy water, and evenly apply it to sealing areas such as furnace door seals, flange connections, and pipeline joints.
If bubbles continue to form in a certain area, it is a leak point and needs to be dealt with in a timely manner.
2、 Atmosphere pressure holding method (applicable to inert gas working conditions)
Inflate and maintain pressure
Close the furnace door and seal it. Introduce inert gas (such as nitrogen or argon) into the furnace to increase the pressure to 0.02-0.05 MPa (slightly positive pressure state). Close the inlet valve and record the initial pressure value.
pressure monitoring
Let it stand for 1-2 hours and observe the pressure gauge reading:
If there is no significant decrease in pressure, the sealing performance meets the standard;
If the pressure drops significantly, it is necessary to investigate the location of the leak.
Locate the leakage point
The soap bubble method (similar to the vacuum holding method) can be used, or a special leak detection solution can be applied to the suspicious area to determine the leak point based on the location of the bubbles.
3、 Auxiliary inspection method (quick troubleshooting of minor faults)
Visual inspection of sealing strip
Open the furnace door and observe whether the sealing strip is aged, cracked, deformed, or adhered by foreign objects. If the sealing strip is damaged, it directly affects the sealing effect and needs to be replaced in a timely manner.
Bolt tightening inspection
Check the tightness of the clamping bolts around the furnace door, which should be symmetrically and evenly tightened to avoid uneven local stress that may cause sealing gaps.
4、 Inspection precautions
Before conducting pressure maintenance inspection, it is necessary to ensure that there are no residual debris in the furnace to avoid affecting pressure stability.
The soap water used for leak detection should have a moderate concentration and should not be too thin or too thick, otherwise it will affect the accuracy of leak detection.
If a leak is found, it is necessary to first release the pressure or break the vacuum before handling, and disassembly under pressure is prohibited.