Ventilation Cooling Problem - Steel Mill Application

[lci]

I have an application where a worker must trim the steel rod ends from a steel rod bundle(coil 6000 lbs @ 1200 F) made in a rod mill. The coils are transported on a hook conveyor and the worker trims 2' off the coil ends. The problem is that the radiant heat and the elevated ambient air temperature creates a heat exposure problem.

Presently there is a 12'x15'exaust hood (pulling 56,000 cfm) over the area and fans blowing on the workers. The hood is 12' above the workers and can not be lowered. The workers can not feel any cooling from just the exhoust hood and the fans blowing on the workers tend to blow hot air onto them.

Any suggestions on how to increase the air flow over the workers and through the hood with out pulling 800,000 Cfm through the hood to get a 20fps air flow over the workers?

 

[ChasBean1]

lci,

Consider attacking this from a microenvironment (not macroenvironment) standpoint. You could save zillions with this philosophy. Protective air-fed suits could require a fraction of the energy cost while maintaining a much higher level of comfort.

If this won't be acceptable, A/C units with ductwork that blows air directly onto most frequented locations could also work.

 

[lci]

Thanks for the reply.

Currently we have two air conditioned supply ducts that blow onto the workers. These ducts create a cross draft and end up blowing hot air across the coils to the worker on the other side.

I have asked about the suits and the health and safety require constant monitoring of the workers if they are exposed to this enviroment. This, I was told, was not a solution.

I have told them that we should stagger the trim stations and blow the up the line on one station and down the line at the other to stop the cross flow. They were not positive with this one either.

My other thought is to set up an air curtain on three sides to help block the air from being pulled into the exhaust hood. If the worker stands on the open side, then air is drawn over him and will increase the velocity due to the smaller free area. Do you think that an air curtain can seal the sides of a exhaust hood?

Just some thoughts.

 

[mdonner]

Just thinking out loud:
Why not used a perforated reinforced duct on floor where workers walk (on duct) to deliver the conditioned air?

 

[lci]

mdonner,

Thanks

 

[sameyer626]

Where is the supplu for teh curtains coming from. You are only going to transfer heat further into the space.

 

[lci]

samayer626,

We wll duct it from the outside.