The molecular pump is a vacuum pump that uses a high-speed rotor to transfer momentum to the gas molecules so that they gain directional velocity and are thus compressed, driven towards the exhaust port and then pumped away for the front stage.
Features
|
Name |
Features |
| Oil lubricated molecular pumps | Small amount of lubricating oil and in the pre-stage vacuum section, with little contamination of the vacuum chamber |
| Grease lubricated molecular pumps | Very small amount of oil and grease, front stage with dry pump for near oil-free clean vacuum |
| Full magnetic levitation molecular pumps | No lubrication required, use with dry pumps for an oil-free, clean vacuum environment |
Common faults and how to deal with them
1、Why does the phenomenon of half hot and half cold occur in molecular pumps?
Reasons：Light or other heat sources nearby
Solutions：Avoid light or heat sources
2、The oil is found to be black during the use of the molecular pump. Or how long does it take for the oil to turn black?
Reasons：Poor cooling, too much load
Solutions：Checking the cooling system or vacuum system
3、During the operation of the molecular pump, the frequency drops from normal to a certain frequency and then returns to normal, after which it drops to a certain frequency and then returns to normal, repeatedly, and the phenomenon remains the same after replacing the power supply?
Reasons：Too large a load, not enough vacuum in the system
Solutions：Checking the system
4、Why did large pieces of broken glass fall into the pump even though it was protected by a protective net?
Reasons：Broken protective grille, broken front stage pipe
Solutions：Optimised system design
5、Why does the molecular pump oil return to the pre-stage piping when the vacuum is very good?
Reasons：Broken or poorly sealed oil sump
Solutions：Inspection of the oil sump
6、Under normal use, why does the molecular pump oil cell crack or deform
Reasons：Overheating, high load
Solutions：Check cooling system or check system
7、Objects such as top wires and dowels often fall out of molecular pumps, such as M5 top wires, etc. Does this have an impact on the use of molecular pumps? How should it be solved?
A: It should be an occasional thing, probably a missing balance peg in the balance, and has no effect on the molecular pump
8、How many calipers should be used for a rubber ring mouth molecular pump to be safe to use?
A: No special limit, at least 3, according to flange size 3, 6, 12, 24, etc.
9、Under what circumstances will the inverter power supply cause a loss or misalignment of the program?
A: ①Voltage instability ②Strong interference ③High voltage firing ④Artificial decryption
10、How is a noisy molecular pump defined? Is there a qualified standard and what is it?
A: Less than 72db pass, noise level is not easy to define, need special instrument and specific test environment
11、Does the molecular pump have clear requirements for cooling? What is the outside temperature required for air cooling? If water-cooled, what are the specific requirements for water? What are the consequences if the requirements are not met?
A: Pay attention to the water temperature and water flow, poor cooling can lead to unexplained shutdowns, broken pumps, blackened oil, etc.
12、The molecular pump power supply has grounding and shielding problems, what should be done in the best way?
A: The power supply itself has a grounding wire, you only need to ensure that the city network has good grounding; shielding mainly refers to the shielding of strong magnetic fields and strong radiation
13、inverter power supply, speed up in the process of automatic shutdown, that is, the display “Poff”?
A: Low voltage
14、Why do molecular pump bearings burn out?
|
Reasons |
Solutions |
| Lack of regular maintenance | Timely maintenance |
| Overheating due to poor cooling | Checking the cooling system |
| Lack of timely oil changes | Timely oil changes |
| High dust content in the extracted gas | Isolation of dust |
15, molecular pump vane broken cause?
In summary, the main points are as follows：
| ① | misoperation; such as a sudden break vacuum, because the gap between the rotor and the static sub-blade is very small, if the blade material is thin or soft, the sudden air resistance will cause the blade deformation, which may cause friction between the rotor static sub-blade, leading to breakage |
| ② | is a foreign body fall into; no installation filter certainly not, in addition to fall into the thing does not have to be how big, but if the hardness enough will cause as much damage, light is caused by the edge of the blade is beaten into jagged, heavy is broken blade. So now the equipment dealers in the installation of molecular pumps will try to change the side 90 degrees or upside down installation, to avoid foreign objects fall into |
| ③ | the instability of the voltage, especially for the magnetic float type of molecular pump damage more |
| ④ |
the efficiency of the pre-stage pump is poor; we know that most of the gas in the chamber is first pumped out through the pre-stage pump, and the vacuum reaches a certain level before the molecular pump starts. If the efficiency of the pre-stage pump is poor, the molecular pump will be more strenuous, slow starting speed, long pumping time, high current, molecular pump temperature rise, etc. |
| ⑤ |
molecular pump maintenance when the dynamic balance is not done, this is the key to technology, poor dynamic balance, vibration will be large, poor pumping efficiency, but also easy to cause excessive wear of the bearing part
|
| ⑥ | The bearing part does not use the original standard bearing, the effect and size is not standard, etc. |
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Post time: Dec-09-2022