o-ring grooves design

[Baraa Karam]

I'm working on some sort of enclosure, I have some limitation in the overall size of the enclosure, and I'm wondering if there is some guideline for the width "T" of the face next to the o-ring groove (as shown in the attached picture). the enclosure's material is Al.

 

[Jboggs]

Well since you have not explained anything about the application it's hard to say it there is a problem. We don't know pressure, or media, or environment, or temperature, or working conditions, or critical nature, or ...

Have you discussed it with an application engineer at the o-ring manufacturer? They have people whose only job is to help you apply their product correctly. Call the manufacturer and tell them you need application assistance.

 

[Baraa Karam]

The pressure is external and it is about 20 KPa , low humidity , temp is about 60 degree Celsius, outdoor conditions.

regarding o-ring manufacturer, I have tried to contact them but there was no respond for too long.

 

[BrianE22]

Since pressure is from the outside, o-ring will get pushed inward. It won't care how wide the outer diameter is.

 

[NRP99]

If this is the standard pipe flanged connection then, obviously, it would be decided by the pipe flange and enclosure flange dimensions.

Nonetheless, you can refer standard flanges for min "T" dimension that you need to maintain.

 

[bcd]

Not sure of the manufacturing steps when making the part, but most likely drilling and tapping of the threaded holes will be towards the last steps. If so, then you want T to be between 1/2 to 1 bolt diameter away from the threaded hole. this should give you enough wall thickness for T to prevent the tap from pushing the wall at the OD. I believe the general rule of thumb is 1/2 bolt diameter, but since you are working with Aluminum, you may want to increase it a little more.

 

[drawoh]

Baraa Karam,

Parker has an o-ring design guide that probably is up on the internet somewhere. I strongly recommend it.

--
JHG

 

[moon161]

https://www.parker.com/Literature/O-Ring Division Literature/ORD 5700.pdf

 

[BrianE22]

I don't think you'll find anything in o-ring groove manuals. There may be a standard having to do with the flange dimensions. I think your value "t" combined with the thickness of the flange would be what you need to look at. Any pressure from the outside will try to bend up that area.

 

[Tmoose]

20 kPa ~ 3 psi ??

Wouldn't take much of a flange to handle, that if it's less than 6"Ø.

 

[TugboatEng]

Your temperature is low and the joint is static. This is a good case for an anaerobic type gasket maker. You don't need an o-ring.

 

[Baraa Karam]

It's not a pipe flange, but it's slimier to it , so there is no standard pipe flange here. the wall thickness of my enclosure is 3mm, and it get thicker around the bolts only and not by much. my main concern is where the wall thickness is only 3mm , this 3mm should fit the groove width and "T1 + T2". and since it is an external pressure so I should be more concern about "T2"

 

[desertfox]

Hi Barack Karam

What are the overall dimensions of this enclosure, diameter, flange thicknesses, bolt sizes, number of bolts and on what PCD are the bolts on?.
You say you are concerned about the 3mm thickness but you haven’t told us why you are concerned, what is it you think might happen to the small thickness?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[hydtools]

T at the bolt hole could be 0 since pressure is external.

Ted

 

[MintJulep]

As a rule of thumb, T1 should be > bolt diameter.

Is your cover a disk? A square? A rectangle? Something else?

How long is the span? What is the area.

Is the temperature constant, or does is change with time?

Is the temperature change big enough that you need to think about thermal expansion and contraction?

Is the enclosure vented, or are you trying to make it always sealed?

Sure, the pressure that you listed earlier is low. But is is constant?

What is the internal volume of the enclosure? How much will temperature change cause the internal pressure to change?

How stiff is the cover? How much will it deflect as the pressure difference changes?

What are you trying to keep out or in?

We can't design this for you with only a cross section of the flange and one bolt.

 

[Baraa Karam]

the shape of the enclosure is oval cone,overall size )62 * 56 oval * 100 length), the cap or (lip)is at the bigger end, the shape is hollow with 3mm wall thickness, the lip is simply an oval 3mm thick Al sheet with 4 drilled holes for the screws, there are 4 * M3 screw to fix the lip to the enclosure, the screws holes are placed within the oval shape, the o-ring groove is in the oval cone part as shown in the picture, the T1, T2, and groove width (W), if I use 1.5mm o-ring that requires 2.2mm groove width , then the remaining width of the wall (within the groove depth) will be 0.8mm. So my concern is, if I made T1=T2=0.4mm , will the (T2=0.4mm) withstand the force due to external pressure (20 KPa) or will it fail (break or crack)?

I hope this make sense to you now.

 

[Baraa Karam]

The enclosure should meet the IP68 rating basically , and it is not meant to remain under water(pressure) more than 30 mins. And the 30 - 60 degree Celsius is the temp range.

 

[MintJulep]

Well, the cross section through a bolt in your sketch would be nothing at all like the cross section that you posted previously.

IP 68 is continuous immersion.

If you game your testing properly, you might make it pass.

Almost certain to leak in the real world however.

 

[Pud]

I think Tug's is the best option. Many years ago we used to silk screen a clutch housing to cylinder block gasket. As a bonus, the clutch housing had a finishing cut removed due to the gap-filling properties it gave.


Politicians like to panic, they need activity. It is their substitute for achievement.

 

[Pud]

OP: Would be interesting to know how this is going to made?



Politicians like to panic, they need activity. It is their substitute for achievement.