This is the stainless steel perforated roller assembly for the Hydro-X Xtreme Xtractor, by Phoenix/Thermastor.
When replacing roller, lay the unit back on the handle so the roller is facing out and at the top of the base assembly. This will be the proper orientation for the directions that follow. First remove right and left sides. Sides are screwed in with 2- #2 phillips head screws on the top and one #2 phillips head screw on the bottom of the base assembly. Once the sides are removed you must loosen the 3 nuts (7/16") on the motor mount. DO NOT REMOVE just loosen. Once loose, from the right side lift the motor assembly to put slack on the drive chain so it can be removed. Remove chain from motor gear and let motor rest. When the chain has been removed from the drive motor gear you must loosen the roller clamps, these are found on far right and left side of the roller assembly. Look for a hole that's slightly larger than the perforation holes. Inside that hole is an allen head set screw (5/32"), loosen these screws, DO NOT REMOVE just loosen, 1-2 turns. This will free up the roller assembly. Push on the center of the bearing on the right side and pull on the gear and chain on the left side at the same time. DO NOT STRIKE just push and pull by hand. You can work out the center shaft which is attached to the gear and once out the roller assembly is free to remove. To replace reverse these steps ensuring that the chain is re-oiled before re-installing the side plates.
When re-mounting the motor and adding tension to the chain there should be roughly 1/8" of slack in the chain. If it's too tight it will damage the motor.