What type of bearing to use in a spinning chimney cowl?

[Chlodnicki]

Hello,

My company is purchasing 12,000 spinning anti-downdraught chimney cowls from a chinese company and the chinese company has asked us what type of bearing to should be used in the swivel mechanism?

The cowl is constructed from s/s and mild steel and sits on a domestic chimney servicing an open fireplace or stove and shields the chimney from the wind preventing smoke and/or fumes being forced back down the chimney. It has a stationary base connected to the chimney and a revolving top. It spins when the wind blows.

The bearing will need to have a long life, the cowl could be exposed to temperatures up to 250 degrees centigrade, cowl will spin at different rpm depending on wind speed, the actual bearing will be covered with a mild steel cap so won't be directly exposed to heat, soot or mositure.

So basically I need a bearing that won't fail or seize under these conditions. Thanks
Greg Chlodnicki

 

[desertfox]

Hi Chlodnicki

The best advice would probaly be given by a bearing manufacturer like :- SKF etc

Regards

desertfox

 

[dvd]

It is a sad commentary on modern life that we can't figure out how to manufacture or engineer products in the West. It sounds like the decision to produce in China was made before an engineering definition was provided. There has to be a better way.... Since money is obviously an issue, I would recommend the cheapest bearing possible.

 

[berkshire]

Chlodnicki (Materials)
40 years ago I used to work for a company that made these things. The bearing was a rod in a tube with a point ground on the rod, and a single ball just slightly smaller than the tube dropped into the bottom with the point resting on it. It was cheap and it worked.
B.E.