Pot Feeder Test

Relevant Codes and Standards

Materials and Components

100 lb lead block

Structural steel

Project Brief:

Carry out preliminary work to develop a mechanism for safely charging a pot of molten lead with a variety of inputs, from 6000 lb lead jumbos to smaller pieces of lead such as scrap anodes.

Challenge:

Mechanism must work with existing equipment including ventilation hoods, mixing pumps, and pot geometry. Splashing as the solid pieces of lead enter the molten lead must be minimized, and worker interactions must be minimized. Mechanism must be loaded via a forklift. In consultations with the client, I/O Design proposed a tilt table operated hydraulically with geometry that would permit the material to slide into the molten lead with minimal velocity. This required testing to establish lead-on-steel and steel-on-steel frictional behavior.

Solution:

I/O Design arranged for a simplified test apparatus to be constructed at a local fabrication shop, and utilized a 100 lb lead block of similar composition but scaled down proportions as the full size jumbos that would be loaded with the actual mechanism. This test apparatus was used to determine the angle at which the payload began to slide, allowing us to determine the coefficient of static friction for lead-on-steel and steel-on-steel. We also wanted to see what the effect was of a transition between steel-on-steel sliding and lead-on-steel sliding, to see if a short section of higher friction sliding could serve to reduce the speed of a lead block prior to furnace entry. We observed that this breakout angle had a tendency to change with repeated tests and further inspection of the lead block revealed that surface condition appeared to exert a significant influence over frictional behavior. Due to the variable surface condition of the various charge materials, frictional behavior would not be sufficiently reliable in service and further work was required to develop a workable concept for this application.