Armour Plated EPS: Improvements for Continuous Duty Operation

Jul 21, 2015

In prior EPS Updates we announced results of our Continuous Improvement program that led to breakthroughs in production speed and economics, as well as more modest upgrades that, collectively, enhance the value of EPS technology. Today, we describe innovations that extend the service life of EPS Cell components and reduce the frequency (and cost) of maintenance. We think of these upgrades as ‘armour plating’ that makes EPS even better suited to the demanding, ’24/7′ continuous duty operation required by mills and desired by many service center processors.

Where do the ideas for these innovations come from? Largely from monitoring and analyzing the maintenance data of operating EPS production lines. First, we examine areas that seem to involve higher-than-expected maintenance. Next, we research alternative designs or materials for these areas and test the alternatives on the EPS Sheet Line at TMW as well as at EPS Producers. Finally, we release the best innovations to the EPS Producers as retrofitable upgrades.

We’ve also held discussions with several large steel mills who are evaluating EPS technology, especially for running harder alloy steels that are difficult to descale by acid pickling. The mills provided guidance on duty cycles and outage restrictions, plus helpful suggestions for an EPS line’s terminal equipment to ensure it stands up to the mill operating environment.

Below are brief descriptions of some recent Continuous Improvement Program upgrades which have been released for retrofit to the EPS Producers and are being incorporated into all new EPS Cells:

MATERIAL IMPROVEMENTS TO EXTEND COMPONENT LIFE

  1. Eductor Motive Jets, which help control the flow of slurry to the Slurry Turbines, are now made from a harder, heat-treated material. This extends their service life from 600 to 8000 hours, so instead of being a monthly replacement item they are now an annual replacement item.
  2. Elbows in Slurry Delivery Piping are now made from a much harder cast material that extends their life from 1200 to 8000 hours. They also use a ‘quick release’ vitalic coupler that simplifies replacement.
  3. Thread Fingers used to guide the leading edge of a coil through the cell are now made of a harder material that extends their life by 25%. Their profile was also modified to reduce the risk of coil head jamming.

INNOVATIONS TO REDUCE OR ELIMINATE MAINTENANCE

  1. An Exhaust Expansion Duct (EED) prevents grit from accumulating in or escaping from the EPS Turbine Chamber exhaust. The EED siphons off grit and moisture from exhaust air flow, returning them to the Turbine Chamber.
  2. New Turbine Chamber Liners. The replaceable RhinoHyde liners meant to protect Turbine Chamber interior walls have now, themselves, been permanently replaced with abrasion resistant AR500 plate. In the areas most susceptible to erosion from slurry exposure, such as passline, thread bar and support bearings, an additional plate with an overlay of special magnets is inserted. The magnets capture and hold grit particles, building up a self-sustaining barrier to erosion.
  3. Magnetic ‘Flinger Rings’ are two-piece shaft collars with a magnetic face that fit around the passline and pinch rolls at the point where they penetrate the Turbine Chamber wall. Their magnet traps grit so it doesn’t reach the wall penetration and degrade the roll bearings, which greatly reduces maintenance frequency.
  4. Rinse Strainers are now placed in the Turbine Chamber rinse system piping to filter out debris that might otherwise clog the rinse nozzles.
  5. Elimination of Hydraulics. Hydraulically actuated control components like pinch rolls and width control have been replaced with electrically driven ones. This eliminates the hydraulic power unit and associated maintenance.
  6. The Internal Top Pinch Rolls are no longer needed and have been eliminated.

LESS DOWNTIME AND SIMPLER OPERATION

  1. Grit Supply Load Cells. Grit levels in the tank feeding the Slurry Turbines must be maintained within prescribed levels. Checking that level used to be a manual operation, but load cells have been added to the grit tank to sense its weight, providing real-time grit level feedback to the operator’s control station. Load cells have also been incorporated into the Automatic Grit Adder, which is the source of makeup grit to the EPS Cell.
  2. New Slurry Additive. An improved formulation of the EPS Slurry Additive has been developed that substantially reduces the ‘foaming’ of the slurry solution that can occur at low temperatures. No more foaming simplifies operation and eliminates the need to use defoaming additives.

FASTER SPEEDS / BETTER ECONOMICS

  1. A New Slurry Turbine Motor and accompanying variable frequency drive package is now available that takes full advantage of the higher grit flows made available by EPS Cell Version 2.2′s curved turbine blades and modified slurry spout design. This delivers up to 15% higher production speeds with no increase in operating cost.

EPS has the advantage over acid pickling of being ‘nimble’ . . . you can process a coil at a time and handle a wide range of materials without compromising its economic benefits. But mills and many picklers don’t necessarily want nimble. They want long, continuous runs of a product and near constant availability of their pickling line. The recent results from our Continuous Improvement Program make EPS even more of the armour plated, bullet proof production system they are looking for.