analysis and troubleshooting of abnormal phenomena in quenching furnace

leakage in different parts of quenching furnace body causes oil in different parts to become Milky White; Abnormal rise or fall of oil level in hydraulic station; A1. O The partition strips fall off; the insulating PTFE sleeve at the water-cooled electrode is burnt; the air switch trips within a short time of starting the Roots pump. To make a correct analysis of these abnormal phenomena, quickly determine the fault location and timely elimination, no doubt to extend the service life of vacuum quenching furnace, improve the utilization rate and repair efficiency, reduce the repair of the shutdown time and repair workload plays a very important role.

1. Different parts of the vacuum quenching furnace leak, turning the oil in different parts into Milky White.

(1) the oil level of the hydraulic station rises, and the hydraulic oil becomes Milky White. there may be three situations in which the oil level of the hydraulic station rises: first. The oil return pipe of the hydraulic system to the oil motor of the furnace body leaks, because the oil level of the quenching oil tank is higher than that of the hydraulic oil of the hydraulic station. Second, the oil cooler of the hydraulic station itself leaks. The cooling water enters the hydraulic station; third, the oil return pipe of the hydraulic system leading to each oil motor of the furnace body leaks in the cooling water interlayer of the furnace body, causing the cooling water of the furnace body to enter the oil tank. Since the oil level of the hydraulic station not only rises and the oil becomes Milky White, the first possibility can be ruled out. Because the hydraulic oil in the hydraulic station is also vacuum quenching oil, even if the first situation occurs, the oil in the hydraulic station will not become Milky White, and the reason why the oil becomes Milky White is that there is water infiltration. Therefore, the occurrence of this phenomenon may be the latter two cases. We pumped the oil out of the tank. Remove the oil cooler. Increase the water pressure to pass through the water to detect leaks. The second possibility can be excluded. We loosened the oil return pipe nut of the hydraulic station leading to the horizontal movement oil motor of the furnace body and the stirring and pumping motor, and found that water flowed out of the oil return pipe of the oil motor of the oil stirrer. This proves to be a third possibility. Remove a section of oil pipe in the water-cooled interlayer of the furnace body and find a corrosion hole on it. Replace this section of pipe and weld it again for troubleshooting.

(2) Mechanical pump oil level rises and pump oil becomes Milky White Mechanical pump oil level rises and pump oil becomes Milky White. It can be concluded that there is moisture ingress caused. There are two possibilities for this phenomenon: the first is the leakage of the pump body. The cooling water in the pump body enters; the second is that the water vapor in the heating chamber is condensed after being pumped by the mechanical pump. Disassemble the mechanical pump, expose the pump chamber, and observe after passing cooling water for 24 h. There is no leakage in the pump chamber. After eliminating the first possibility, carefully check the heating chamber. It was found that there was a very small leakage point near the welding sleeve of the fixed graphite support column near the middle insulation door of the 6 supporting horizontal guide rails. After welding, the failure phenomenon disappeared.

(3) The bottom oil of the quenching oil tank becomes Milky White. When the cooling chamber door is opened, water droplets drop on the cooling chamber door. Found the phenomenon can be sure that the cooling chamber leakage. We wiped dry the door of the cooling chamber, passed cooling water to the furnace body, and found a leak. The water droplets on the furnace door were when the parts were quenched. The water in the oil evaporates into water vapor, which condenses after meeting the cooling chamber door. So we decided to pump out the vacuum quenching oil. During the pumping process, we found that the bottom vacuum quenching oil was Milky White. After pumping, we dried the oil tank and found no obvious leakage. After closing the furnace door and vacuuming to the working vacuum degree, open the furnace door by inflation, and check that there is a drop of water on the oil tank wall. Troubleshooting after welding.

2. The oil level of the hydraulic station drops. Oil level rise in the quenching tank is found in use. The oil level of the hydraulic station drops more. Therefore, it is certain that the rise in the oil level of the quenching oil tank is caused by the infiltration of hydraulic oil from the hydraulic station. We pumped out the oil in the quenching oil tank, wiped the tank wall dry, and found obvious leakage points. At this point, close the furnace door vacuum to the working vacuum degree, from the observation hole of the furnace door to see that there is a lot of oil at the oil mixer like a fountain. Inflate open the furnace door, check the oil mixer, and find that the sealing ring in the oil motor is damaged. Replace with a new sealing ring. After a period of use, no drop in the oil level of the hydraulic station is found.

3. The insulating PTFE sleeve at the water-cooled electrode is burnt. This kind of phenomenon occurs. First observe whether it is local or overall burnt. Local scorching is due to the decrease of insulation resistance and carbon fiber pollution, which leads to local short circuit between furnace body and electrode. The overall scorching is caused by the blockage of the cooling water jacket at the long-term service electrode of the vacuum quenching furnace, which increases the local temperature at the electrode seat and causes the overall scorching of the insulating PTFE sleeve. Different approaches are taken to different phenomena.

4. AI2O3 partition strips fall off Al in the two graphite guide rails on the hearth of the heating chamber. O; The main reason for the shedding of the partition is the bending deformation of the workpiece table. Due to the bending deformation of the workpiece table, the loading basket on the workpiece car is the same as A1 O. Spacer contact. The workpiece car is easy to drag the A1 O partition bar to fall off during the horizontal entry and exit process.If this kind of phenomenon is found, the bending deformation of the workpiece table should be reshaped or replaced, otherwise, it is easy to cause the collapse of the hearth.

5. this kind of phenomenon was found when the air switch tripped within a short period of time when the roots pump was started. we turned the motor coupling of the roots pump by hand, and the hand felt very relaxed, which could eliminate the faults such as pump stuck or dead spots. Start the mechanical pump to vacuum, and the mechanical pump will quickly pump below 133 Pa to meet the conditions for starting the Roots pump. At this time, it can be concluded that the mechanical system has no fault, and the problem may lie in the electrical system. Upon inspection, the Roots pump motor has two short circuits to the casing. Therefore, after replacing the new motor with the same specifications, it was put into trial operation again. The above phenomenon was still found. The operation was stopped immediately. The air switch was checked again. It was found that one contact was ablated. The dynamic and static contacts of the contact were not in contact but only in two phases, causing the motor to burn out due to lack of phase operation. Replace the air switch with the same specification.