Bearings inside an oven 1

[som1973]

Hi,
Does anyone has used bearings inside a Industrial
oven.(Inside baking chamber)

We tried to use high temperature bearings in an oven but bearing seized after 3-4 weeks of operation.

Can anyone shed more light on this........

 

[electricpete]

To get some educated guesses you might want to provide more info.
Temperature in the oven.
Temperature rating of the bearings
Bearing part number / style
Bearing lubrication method. Greased?
Shielded? Sealed?
Bearing Speed
Some idea of expected bearing load in relation to bearing load rating.
Pictures would be nice.

Disclaimer: I'm not sure this is something anyone can solve, and I'm certainly no expert.

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(2B)+(2B)' ?

 

[MikeHalloran]

If you got 3+ weeks to seizure, you can't be too far off from a solution.

The usual solutions include either:
- extending the shafts so the bearings are outside the oven, or
- bringing a more moderate outside environment inside the oven, just around the bearings.

The next thing I'd try is something like NASCAR brake ducts to bring outside air to the bearings and to take away the heated air from their vicinity. If they're insulated well enough, they should not interfere with the oven's control loop.



Mike Halloran
Pembroke Pines, FL, USA

 

[dvd]

Define high-temperature bearing, please.
Is this a rolling element bearing?
Graphalloy makes some high temperature bearings.
I have used rolling element bearings without seals and a constant flow of grease for some moderate elevated temperatures. But, this cannot allow a pile of combustible crud inside the oven...

 

[Tmoose]

"We tried to use high temperature bearings..."

Superconducting guys think −243.2 °C is "high temperature"

During the summer my wife thinks 78°F is "like an oven."

 

[dinjin]

Is the bearing ceramic? Does is have a cage of some sort separating the rolling elements. Is it a ball bearing, roller bearing, or what?
I assume if it does not have grease or if lubed a dry coat of some sort. Tell us more!

 

[sreid]

Carbon bearings are often used in high temperature applications.

 

[Hippo41]

SKF make a range of bearings suited to very high temp operation - the VA 201/ VA 228 types. They have graphite lubricant and cages. Have you looked at them?

 

[tdenner]

Hi,

if you use a bearing inside an oven, the temperature (normally) does not allow the usage of any kind of grease. So you have to use a solid lubricant like graphite (already mentioned) or a kind of bearing which avoids adhesion or cold welding between raceway and rolling elements in dry running conditions.
It's not necessary to go to a all-ceramic bearing. To reach the described effect it's enough, if one component is made of ceramic. Either rolling elements or rings. This kind of bearing is called a hybrid bearing.
High nitrogen steels like Crondur 30 are resistant up to 450degC, super-alloys like Inconel 718 are resistant up to 800 degC.
There are only two things you have to keep in mind:
1. the load capacity will decrease. In dry running conditions it will be 1.56% of the value you will find in a catalogue.
2. the raw material quality for ceramic components is very important. If there are particles in the raw material (bad, but cheap quality), the end product will fail.

Hope this helps a little bit. To help more, we need more information like temperature, loads (radial and thrust)...

Greetings

Tobias

 

[Skogsgurra]

Scrollerwheel, novel bearing architecture thread821-313609

The "neighbour" post. No grease, no rolling friction.

Gunnar Englund

http://www.gke.org

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