Thermal Expansion of an Oil Seal
Thermal Expansion of an Oil Seal
(OP)
All,
Question about thermal expansion of oil seals.
I have seal with a clearance between the top and bottom at the horizontal joint of .160". This measurement was taken with the seal pushed all the way to one side as to close up the left horizontal joint and measurement of .140" taken at the right horizontal joint.
Question: how do I calculate how much this seal will grow to close up during operation of the unit. If I treat it as simply linear, I get the following:
Aluminum has a thermal growth coefficient of 12.3x10^-6 in/in F. The diameter of the seal is 17". The temperature I'm going to is roughly 400F let's say. Can I use a straight calculation for this or do I need to take into account that this is a half circle?
This is what I get treating the seal as linear:
Circumfereance of the entire seal (both halves is 53.4. Half circle would be 26.7. Therefore: .0000123 * 26.7 * 400 = .131364". Is this correct or do I need to use a different formula since this is essentially a half circle?
Question about thermal expansion of oil seals.
I have seal with a clearance between the top and bottom at the horizontal joint of .160". This measurement was taken with the seal pushed all the way to one side as to close up the left horizontal joint and measurement of .140" taken at the right horizontal joint.
Question: how do I calculate how much this seal will grow to close up during operation of the unit. If I treat it as simply linear, I get the following:
Aluminum has a thermal growth coefficient of 12.3x10^-6 in/in F. The diameter of the seal is 17". The temperature I'm going to is roughly 400F let's say. Can I use a straight calculation for this or do I need to take into account that this is a half circle?
This is what I get treating the seal as linear:
Circumfereance of the entire seal (both halves is 53.4. Half circle would be 26.7. Therefore: .0000123 * 26.7 * 400 = .131364". Is this correct or do I need to use a different formula since this is essentially a half circle?





RE: Thermal Expansion of an Oil Seal
RE: Thermal Expansion of an Oil Seal
Thus, thermal expansion of one side of the original 0.160 gap is .0000123 * 26.7 * (400 F - 80 F)
But you need to show why the other side of the 0.160 gap is also Al, and is also at the same same change in temperature, and so why is the other side of the original 0.160 gap not also growing by the same thermal expansion?
RE: Thermal Expansion of an Oil Seal
RE: Thermal Expansion of an Oil Seal
RE: Thermal Expansion of an Oil Seal
hence my question above: why are you apparently assuming that the ID of the two sealing surface will stay the same? Both sides of the 0.160 gap will move outward a little bit, but the gap itself will get larger by (thermal expansion of Al inch/deg F) * (0.160 inch) * (120 deg F - original deg F)
RE: Thermal Expansion of an Oil Seal
See picture:
RE: Thermal Expansion of an Oil Seal
In your particular application, you may not be looking at the complete picture. How does the seal housing expand due to the increase in oil temperature? How is the seal ring retained in its housing? Is the seal spring loaded in the radial direction?
Best of luck!
RE: Thermal Expansion of an Oil Seal
Seriously, something else is wrong (wrong seal sent to your plant? wrong machined diameter of the CT set at that joint? Wrong setup of the seal housing?) or at questionable to the specific person responsible for your oil seal, but you need to get your PM IMMEDIATELY to get an alert out to the vender of the seal and your CT vender to get an answer.
It "might be OK" - as just mentioned, the seal housing may be cut short at the horizontal joint while the oil seal being clamped by the upper and lower housing into position may be just fine.
If this were a Siemens machine, I'd call the district manager (or whatever your CT representative for the CT manufacturer is called in your organization) and send him/her that last photo.
RE: Thermal Expansion of an Oil Seal
RE: Thermal Expansion of an Oil Seal
Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376: Eng-Tips.com Forum Policies.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529: Translation Assistance for Engineers.