Back in the "70's" I worked for a company (Fiber Bond) that made non woven fiber products, the material was basically glued together by a binder that was for the most part just a paint, after each application of the binder (2) it would pass through a large oven for curring (3 passes 3 conveyors), this conveyor used nothing but thin metal tubes about 1" in diameter flattened on the ends with a hole drilled in each end that bolted to the drive chains, chains were keyed to the drive shaft so they wouldn't change position wit the other side, well we have the same problem, one of the tubes would break loose and destroy half of the conveyor before it could be stopped.
Because this conveyor was operated at different speeds for different products, trying to use some kind of load detection was fruitless, we tried slip clutches, a spring loaded tensioner with a limit switch, all failed to stop the line, so we turned to optical, because the tube would fall down between top and bottom of each pass, it was possible to mount the IR transmitter and reflector inside of the conveyor, we put one on each side about a foot from the side, and aimed them in a cross fire pattern to the reflectors on the other end, if anything was to drop in their path it would trigger an EMG stop and light a conveyor fault light we set up.
The drive motor was DC so dynamic braking was employed to bring it to a stop as fast as we could, it would still sometimes take out a couple more bars, but at least they wouldn't get all wrapped around everything, as it turned out it also solved another problem that if the fiber web product broke (operator set speeds wrong to other conveyors) it would stop the whole line without the fiber web jambing up and doing more damage.
The line was a continuous run and speed sinked line so if one part had to be shut down it all had to be shut down.
With an air flow type system, I would presume the space inside of the conveyor would be open similar to the drying ovens I had?