Help with Air tight sealing in a consumer appliance 1

[vighnesh2019]

Hello fellow engineers

I'm in real need of help with regards to this new consumer appliance I'm designing.
Basically, I need to completely seal an SS jar with a lid at the top and a blade assembly at the bottom.
Imagine a blender jar, but with an SS body.

I'm dealing with negative pressure, -75kPa = -10.9 psi = -0.75 bar = -0.74 atm.

I cannot use bearings on the blade shaft, only sintered bushes. O-rings, oil seals, gaskets and lip seals are possible options. A combination of these is quite possible
With these items, I don't know what parameters to consider for designing a proper sealing. I need a design that can be validated with calculations.
Another constraint is that the lifetime of the sealing needs to be considerable, i.e, 5-10 years.

Can you guys please help me?

 

[Compositepro]

5-10 years on a consumer shaft seal. Not likely. What will it be exposed to and what about cleaning?

 

[vighnesh2019]

@compositepro Thank you for the response! let's consider 2-5 years lifetime then. it will be exposed to food (solid and liquid) and cleaning by water and soap, worst case dishwashers.Can you help me please?

 

[Compositepro]

Food service requires a sanitary seal. That mean that it must be cleanable so it does not breed bacteria. A tapered shaft inside a tapered hole can act as a seal and bearing. A teflon sleeve between the parts can reduce the need for lubrication.