Prior art for Dual Air Drying Arrangement

Question

Many people in the commercial vehicle industry use a "twin" air drying arrangement.

Patent #us8118911, originally filed Nov. 10, 2006, and was granted on Feb 21, 2012, seems ridiculous to me.

For example, here is a twin dryer manufactured by the SKF corporation: H.C. Dual Turbo-2000

Would this dryer constitute prior art?

Here is claim 1 of the patent:

A device attaching a pair of desiccant cartridges such that air flows to the pair of desiccant cartridges in parallel, the device comprising:

• an inner chamber; a first fluid flow passage for communicating air to the inner chamber;
• a pair of extensions, each of the pair of extensions adapted for mounting one of the pair of desiccant cartridges;

wherein each extension is spaced at a substantially equal distance from the inner chamber; and a second and a third fluid flow passage, each fluidly connecting the inner chamber with each of the pair of threaded extensions, compressed air flowing in substantially the same direction at substantially the same time through each of the second and third fluid passages in substantially equal amounts.

More possible prior arts with an original filing date before 2006:

Patent #US3717974

Patent #US5871564

Patent #US4802899

Answer 1

I do not see the word desiccant in those references. Take a look at Patent number us4673420 from 1987. I do not see it listed in the face of the patent in question so it is likely something the examiner didn't look at. It may not be seen as teaching the "inner chamber" of claim 1.

Answer 2

I wonder if the SKF product is unconsidered because it is patented and mentioned in the prior art. The patent touts its usefullness "for supplying dry air to a storage facility" which is a different industry than the air brake industry? US7097696