Seal Question

[eobana]

Hello,

I have been browsing this forum for a while now, but have yet to make a post until now.

I have been asked to come up with a method for sealing (what is essentially) the gap between a box and its lid (both steel). The lid will move up and down approximately 2mm (4mm total movement) and undergo high vibrations.

My first thought was to simply design a seal to be placed between the lid and box frame that can be easily compressed and uncompressed while also maintaining a proper seal.

And from what I have read, it seems that O-rings are, and please correct me if I am wrong, the bread and butter of sealing (cheap, simple, compact etc.) Unfortunately, it doesn't seem they are made for such motion (compressing and uncompressing while remaining sealed).

I know there are many other factors (pressure, fluids, etc.) when designing the seal, but I am really just looking to be pointed in the right direction. Is there something I am missing within O-rings? Or should I be looking in another direction? Any books that might cover this type of motion?

Any help would be greatly appreciated,

Eric

 

[flexibox]

It would help if you provide a sketch and some details as to what fluid/gas it is you are trying to seal. Is the Box under pressure? what are the clearances between the Box & lid? It does not sound like an application for an Oring but if you provide some more information, I am sure this forum will assist you.

 

[eobana]

Flexibox,

Thank you for your response.

The system will submerged completely in water. A tube will connect the inside of the box to free air, so the pressure that the seals must withstand is relatively low.

At rest, the clearance between the box and lid will be 4-5mm. The outer edge of the box is 10mm thick.

One last thing to consider is that the lid will not always stay completely horizontal. For example, there may be a case in which on one end, the lid has been pressed down 2mm and the other end has been lifted 1mm (from rest).

That is all I can think of at the moment. I have attached a very simple drawing of the system.

Again, any help would be greatly appreciated.

Eric

 

[Pumpsonly]

it looks like you will need a bellow seal. If you can make container in cylindrical instead of rectangle,it will be much easier.
Just find a rubber tube with the correct size and flexibility and sleeve it around the cylinder and the lid will do.

 

[flexibox]

that is not a very good drawing to help you! The bellows sounds good but what guides the lid to go up and down? Do you have beter drawings than what you supplied? If you look at a bellows you still need to seal it to the box & lid.

more detail may help us help you

 

[eobana]

Pumpsonly,

Thank you for your input. I like the concept of a bellow seal for my application, but I can not change the shape to a cylinder.

Using a rubber tube as basically a flexible O-ring, may be possible. I am wondering though, is this an established technique for which I can do more research? Is there a company or book that may provide me with more information?

Flexibox,

Here is a quick CAD with basic dimensions (mm). My apologies for being unclear, I'm a bit hesitant to post the design of our system on the internet.

The lid is attached to what are basically very high strength springs. Movement along the other two axes can be considered negligible.

Again, thank you very much for your help,

Eric

 

[flexibox]

Eobana
I am not sure that you will find a bellows to this application, here is a link that may assist you :

http://www.buckhornrubber.com/rubber-boots-bellows-manufacturing.asp

I have also found airseals that may be suited to you application and seems more practical however you may need modifications to lid/tank to suit. see below:

http://www.tss.trelleborg.com/com/

http://www/media/downloads/catalogs/airseal_gb.pdf

Sorry I cannot assist any further with this enquiry.

regards

 

[eobana]

Flexibox,

Thank you for all of your help. I will look further into the airseals as, I agree, they do seem more practical and suited for my design.

Best,
Eric