We talked about bad practices two weeks ago and received some great comments we want to share:
I agree with the bad practices of not sizing equipment to meet its functions, and adding band aids to try to make it function is never rewarding.
I have seen more cost and problems occur by over designing equipment than undersizing. It seems that some people (engineering) would design higher percentage service factors to pumps, motors, valves, and etc. that is out of the operating range of processes' attendant design capabilities. This leads to variations in the process which causes much unforeseen problems that causes product quality, operational performance, and money wasted.
Bill Avent
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How about trim squirt and shower water filtration? I have seen better and worse but never a true operator and maintenance (think bottom line) friendly setup. If there is a problem just add another filter.
At one mill the water goes through a sandfilter, then a coarse filter to remove sand then bag filters before the high pressure pump, more filters for low pressure showers, still more at various final points of addition. Typically the area is poorly lit, squeezed in between a condensate receiver and vac pump. One installation I know is downright unsafe to open and clean requiring the operator to balance on a 2" water line while holding on with one hand. If the filter is operator cleaned there is likely no good way to clean it so he lays it on the floor and blasts it with a water hose as it rolls around. Or if it's a bag filter it blows out and plugs everything, Pressure or flow alarms are either absent or not working so filter cleaning is done after the breaks and defects start. What is truly baffling is that everyone on or near the machine will tell me how a bad trim squirt water supply is guaranteed to cause downtime!
Bruce Jeffery
with "LGMI Frontiers" in the subject line.