How to select rotary encoder in outdoor or harsh environments?

Some netizens to email asked, his equipment used in the field, the environment is dirty, and afraid of damaged encoder.

My company has aluminum alloy (special requirements to do stainless steel material) seal protection shell, double bearing overload, an encoder on the outdoor not afraid dirty, steel mills, can be used in the heavy equipment.

But if there is a space encoder installation part, I suggest adding a protective shell on the outside of the encoder again, to strengthen its protection, surely unexpectedly encoder are precision components, an encoder and a protective shell of value is still a certain gap.