Can a mechanical shaft seal operate and survive without lubrication?

Question

In a compressor application where operation is oil free, but the shaft must be well sealed against leaks and construction costs must be kept to a minimum, a mechanical shaft seal fits all design specifications but I anticipate a lack of lubrication may present problems leading to premature wear and failure.
Typically, the sealing surfaces may be polished carbon against creamic. Other material options are available.
Pressure drop across the seal when operating should not exceed (for my application) 35 PSID. When off, the pressure differential may be as high as 135 PSID. In some cases the compressor may operate with a negative internal pressure that should not exceed 0.5 atmospheres.
Due to a wide variety of chemicals in the gases, reasonably inert materials that can tolerate a wide variety of temperature ranges are best but the main issue here is: Can the sealing surfaces survive without any lubricant.
Comments and insights please!
Any recommendations?

Answer 1

There are seals that use a ferrofluid that contains particles that coagulate in the presence of a magnetic field. They make a gas tight and liquid tight seal. Since they are a form of liquid they are immune to the friction found in solid surfaces.

Answer 2

There was ATS 1 was launched and the satellite was spin stabilized and the 6 & 4 ghz antenna had to point to the earth. They wsed a hard steel shaft that turned in wafers of telflone and brass. The teflone is the lubricant as in space oil's will evaporate. Hope this helps.

Answer 3

I think what you're looking for is a dry gas seal. These are oil free, do not need any lubrication, and use a buffer gas (usually nitrogen) to keep the process fluid from leaking. There are a number of vendors who make these type of seals, for an example go to:
http://www.johncrane.com/amer/english/product/28EXP.html
for an example.

Answer 4

Yes. That is what machanical shaft seals are commonly designed to do.
The one described by Phillip H is a typical one and they do run continuously for long durations without any direct fluid lubrication.

Answer 5

Uhhh, im not confident in my answer but you say the operation is oil free, thats unheard of or at least to my knowledge. Usually there is some kind of lubricant for any type of sealing. I dont know what kind but usually there is a lube neccessary for it. Good Luck

Answer 6

A teflon coated shaft where the seal rides should do the trick.