The tempering electric furnace cannot be evacuated under vacuum

The inability to vacuum up the tempering electric furnace under vacuum may be caused by various factors such as poor vacuum system pumping, gas release, and air leakage. The following are the specific reasons and corresponding solutions:

Poor vacuum system extraction
Reason:
The poor pumping speed of vacuum pump units such as mechanical pumps, Roots pumps, and oil diffusion pumps may be due to factors such as high pump temperature, mechanical pump oil failure, or pump leakage.
The vacuum degree of the front-end mechanical pump, Roots pump, and oil diffusion pump does not meet the requirements.
resolvent:
Check if the inlet valve of the pump cooling water is open, and check if the water flow in the return pipeline has decreased due to dirt blockage or pipeline leakage, resulting in poor cooling effect and increased pump oil temperature.
Check whether the oil level of the mechanical pump is below the lower limit, whether the pump oil is oxidized or contaminated, whether the pump oil is emulsified, and whether the type of pump oil added is inconsistent with the specified oil number of the pump.
Check whether the pump itself is leaking, and whether the assembly accuracy of the slide valve ring, eccentric wheel, slide valve guide rail, pump shaft, etc. meets the requirements.
For situations where the vacuum degree of the front-end mechanical pump, Roots pump, and oil diffusion pump does not meet the requirements, they should be checked and the faults should be eliminated one by one.

deflate
Reason:
Improper selection of materials for the vacuum system and furnace body resulted in material deflation.
Poor vacuum cleaning causes deflation.
resolvent:
Choose appropriate materials for the components of the vacuum system.
Properly maintain the dryness and cleanliness of the vacuum system, and if necessary, perform baking and degassing under vacuum conditions.

air leakage
Reason:
Defects in the raw materials of the furnace body and air leakage caused by poor processing and assembly.
There may be air leakage points at the sealing points of rubber rings, welds, pipeline connections, etc. in the vacuum system.
resolvent:
Use static boosting method to determine whether there is air leakage in the vacuum system. After pumping the container to a certain pressure, close the vacuum valve and separate the container from the pump. Due to gas leakage from the container and material release, the pressure inside the container will change over time. By measuring the pressure in the container with a corresponding vacuum gauge at regular intervals, a pressure time curve can be plotted, and the leakage factor can be identified by analyzing the curve.
For gas leakage at the sealing and welding joints of the rubber ring, flame method or ionization tube leak detection method can be used to search for it. The flame method utilizes the principle that airflow can cause the flame to deviate, gradually searching near suspicious points; The ionization tube leak detection method utilizes the sensitivity of the ionization tube to certain gases under high vacuum conditions for leak detection.
After finding the leakage point, carry out corresponding repair work, such as replacing the rubber ring, re welding, etc.