On 2018-08-08 14:48:54
Vacuum sintering furnace leak detection method
Vacuum sintering furnace furnace atmosphere will directly affect the product's surface treatment effect, the atmosphere in the furnace is determined by the tightness of vacuum furnace, so to ensure the quality of workpiece, the first thing to keep the vacuum furnace gas tightness is good, the vacuum annealing furnace gas tightness check the difficulty lies in the furnace pipe area is large and complex, and easy to leak position is various, the check to the air tightness routinization and institutionalized. Next, Huachen vacuum furnace will introduce the leak detection method of vacuum sintering furnace in detail:
1. Determine the key parts of air tightness inspection
These key areas generally include:
1) Replace the parts of the equipment during maintenance. The furnace body and pipeline parts that have been moved during maintenance should be regarded as the key parts of inspection.
2) Opened top cover, bottom cover, perforation hole and access door.
3) Sealing roller joint at the entrance.
4) Expansion joints on furnace shell and circulating pipe, furnace roll flange, heat exchanger flange, instrument flange and welding mouth, etc.
5) Water-cooled pyrometer, camera, water-cooled heat exchanger, etc.
6) Sampling pipe fittings of analyzer.
2. Check the positive pressure
During normal production, the annealing furnace should be maintained at a micro-positive pressure of 150-300pA.
1) Judgment of leakage. Observe online oxygen PPM analyzer measurement data, when a section of residual oxygen suddenly significantly increased, it may be the furnace shell or circulation pipe leakage.
2) Inspection methods and tools for leakage points. Hydrogen detector in tool room. The method is to ensure the hydrogen in the furnace above 3%, using portable hydrogen detector to check the confirmed air tightness of the leakage furnace section, the key part is the top repair weld, etc. The hydrogen detector will give an alarm when the leak is detected.
3. Check the negative pressure part
The suction end of the circulation fan is negative pressure. If the negative pressure part leaks, the air will be sucked into the furnace.
1) Judgment of leakage. By observing the changes in the measured data of the online analyzer, we can determine whether the fan has leakage.
2) Inspection methods and tools for leakage points. The negative pressure leakage point can be checked by the above method, the negative pressure into positive pressure, and then checked by hydrogen detector, or check by helium leak detector, a special equipment for negative pressure leakage detection.
4. Treatment of leakage points
Annealing furnace is always in working state, for some leakage points can be taken to play high temperature sealant and other methods to do temporary treatment, to have the opportunity to stop the furnace to do a thorough treatment.
Repair welding of cracked parts; The aged or damaged gaskets and rings should be replaced. Replace defective parts such as expansion joints; Tighten the loose bolts; Apply high temperature sealant.