Turbo pump - vibration and noise at a certain RPM

In summary: The vibration definitely seems to cause the scraping noise. It never occurs at any other time.The pump looks to be in excellent condition otherwise. It looks pristine inside and the bearings are smooth and not loose or tight.I’m just concerned about the noise and vibration because it doesn’t seem normal. I have never worked with a turbo pump before so learning here.Do you think I should just run it and hope for the best or definitely try rebuilding it?
  • #1
Plat
48
2
I have picked up a used pfeiffer turbomolecular pump and controller for pretty cheap.

It runs like a champ, completely smooth and quiet except for when it’s first starting up.

As it approaches 5500 rpm, it starts vibrating somewhat and sometimes produces a momentary scraping noise when the vibration is worst. This noise then stops and the vibration fades away as it continues speeding up.

The vibration definitely seems to cause the scraping noise. It never occurs at any other time.

The pump looks to be in excellent condition otherwise. It looks pristine inside and the bearings are smooth and not loose or tight.I’m just concerned about the noise and vibration because it doesn’t seem normal. I have never worked with a turbo pump before so learning here.

I don’t understand why, if the vibration was caused by the rotor being off balance, wouldn’t the vibration keep getting worse at higher speeds?

Do you think I should just run it and hope for the best or definitely try rebuilding it?
 
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  • #2
Plat said:
I don’t understand why, if the vibration was caused by the rotor being off balance, wouldn’t the vibration keep getting worse at higher speeds?
could be hitting a resonant frequency of the bearings or something at that particular speed but only that speed.
 
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  • #3
A scraping noise is never good. A slight increase in vibration at one or more points is normally because of a mechanical resonance in the rotor, that's normal during a spin-up. I would suspect it was dumped hard a few times, warped a few blades to almost touching (touching slightly during max vibration) and is slightly unbalanced causing stress on the blades at high speed. It might blowup in 30 seconds pumping a large gas load or it might last years with a light load and minimal stress.

If it does fail at full speed the results can be expensive.
26528430377_9c209e2cd1_z_d.jpg

A clean destruction.

A dirty one on an Ion Implanter at full beam power.
24253585757_6fc94d1aa3_z_d.jpg

Every bolt nut sheared off as the turbo lifted from the chamber at e-5 Torr vacuum.
24253573487_4eb47a3a37_z_d.jpg

Found a few that hit the top of the enclosure.
25299824158_33730f743c_z_d.jpg

The studs are designed to break at X pull. This reduces the possibility of the chamber wall being warped
by a turbo failure.
38254901395_bdfee34968_z_d.jpg

Ion source and beamline pumps
24253556567_b3097e596a_z_d.jpg

Turbo parts inside ion source chamber. Ion beam manipulator.
 
Last edited:
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  • #5
phinds said:
Ouch !

It dusted all the product in the machine with graphite combustion/destruction products
246159

The shiny edge on the top wafer is what they all should look like. The once white label on top of the wafer holder is what every inch of the normally clean processing end chamber looked like after the implosion shock-wave traveled inside the machine from the source failure.

His turbo was pretty cheap because the risk of damage is high during a turbo failure.
 
  • #6
Send it back to the manufacturer for evaluation or rebuild. Very likely the lowest-cost approach.
 

1. What causes vibration and noise in a turbo pump at a certain RPM?

Vibration and noise in a turbo pump at a certain RPM can be caused by a variety of factors, including unbalanced rotating parts, misalignment, worn bearings, or fluid turbulence. These issues can create vibrations that can lead to noise and potentially cause damage to the pump if left unaddressed.

2. Can vibration and noise in a turbo pump be harmful?

Yes, excessive vibration and noise in a turbo pump can be harmful. It can cause damage to the pump itself and other surrounding equipment, as well as potentially affect the accuracy and efficiency of the pump's performance. It is important to address and minimize vibration and noise to ensure the longevity and effectiveness of the pump.

3. How can vibration and noise in a turbo pump be measured?

Vibration and noise in a turbo pump can be measured using specialized equipment such as accelerometers, vibration analyzers, and sound level meters. These tools can help identify the source and intensity of the vibration and noise, allowing for proper troubleshooting and corrective actions to be taken.

4. What can be done to reduce vibration and noise in a turbo pump?

There are several steps that can be taken to reduce vibration and noise in a turbo pump, including balancing rotating parts, ensuring proper alignment, replacing worn bearings, and implementing vibration-dampening materials. It is also important to regularly maintain and service the pump to prevent any potential issues from arising.

5. Can changes in operating conditions affect vibration and noise in a turbo pump?

Yes, changes in operating conditions such as flow rate, pressure, or temperature can affect vibration and noise in a turbo pump. It is important to consider and monitor these factors to ensure the pump is operating within its recommended parameters and to address any changes that may lead to increased vibration and noise.

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