Tube coolers?

I ran across this old booklet while looking into the subject of tube coolers.

Very interesting reading about tube reliability, but fairly technical. It does seem to suggest that cooling the glass is very helpful, but only mentions blowing air on them as a strategy. It's amazing how much has probably been forgotten about tubes :)

Thanks again for that, and especially to Auxetophone for that great book! I really appreciate that great find.

Has anyone found that the Pearl PCF or Herbie's Tube coolers/dampers have helped extend the life the tubes they have used them with? I'm just curious.

Also regarding Gundam91's post about putting a ground wire on each of the Pearl PCF tube coolers. My tube amp has a ground lug in the rear. Would I connect the wire from the tube cooler to the ground lug? I'm thinking I would need to connect the wires from each of the coolers to some other metal chassis.