Top Plant Fixes to Plan for Winter Downtime
BY Sandy Lender
Plant components providers offer more than iron in this industry. These companies often employ salesmen and engineers who have been in the trenches alongside plant managers, operators and groundmen for years. Their combined knowledge is something we wanted to tap into as we head into the 2023-24 winter season to help producers make their best plans for most efficient use of seasonal downtime.
Before you shut down for the winter, give your facility a thorough inspection. Take a temperature gun or thermal camera, digital camera, and a can of spray paint with you as you and your safety spotter go around to each of the areas the experts have listed in this article. You’ll want the temperature gun to measure hot spots where the iron is wearing thin and to double-check electric panels. Use the camera(s) to document issues and then spray paint to mark “items” for the maintenance crew to address. Even with today’s software and apps to assist in documentation, tracking, scheduling and so on, these old-fashioned best practices can save some time and angst when it comes to sharing information and getting repairs underway efficiently.
Even with sources not included here, a common theme was to “look for wear.” Overall, the trend was toward shoring up what you already have in place—when possible. After reviewing some of the areas and componentry listed below, you’ll see the need to perform a second inspection after the plant is shut off and systems are locked out/tagged out for best safety considerations. Even those hard-to-access areas need to be checked so they aren’t offering an unwelcome surprise in the middle of operations in 2024. Here’s the advice of seasoned professionals for mapping out this year’s plant maintenance for best use of your time and money, and best season start-up next spring.
Take a temperature gun or thermal camera, digital camera, and a can of spray paint with you as you and your safety spotter perform a thorough inspection of the plant.
Travis Sneed, the vice president of sales and operations at BROCK, Chattanooga, Tennessee, recommended specific components to inspect, including the cold feed bins, drum, drag, silos, baghouse and electrical systems.
- At the cold feeds, look for wear on the bin walls, conveyor belts and idlers.
- At the drum, look for hot spots and wear. Also check the tires/trunnions for unusual wear.
- At the drag, check the chain and sprockets for wear.
- At the silos, look at the bottom gate and cone for wear. Check for bulging skin, which will be a sign of holes in the silo.
- At the baghouse, look closely at the ductwork for any visible hot spots or signs of wear. You’ll also look for hot spots in the baghouse itself. Check the baghouse bags, too. Check the fan blade for wear.
- With the electrical systems, make sure cables and connections are still in good condition. Inspect switchgear for any abnormalities such as evidence of water or heat exposure.
Steve Klein of Clarence Richard Company shared, “While there are many items to look at, I like to think of systems points that are commonly overlooked.” Klein listed drives, aggregate wear surfaces, plant fluids, plant air systems, and plant cords and wires as the top five areas he’d recommend the plant maintenance personnel walk up to and inspect. When using the thermal camera, point it at the electrical system.
“When one plant I was at first got a thermal camera, they looked at the switch gear, which made sense,” Klein shared. “Then as we looked at the control terminal strips [we] had a large surprise to find how well a loose terminal showed up. Since then, control wiring was added to the list to check with switch gear, gear boxes, top of the baghouse and the ductwork with the camera. Thermal camera surveys recorded make a great reference to show wear in many areas of the plant. It can even show liners getting thin, plugged hot oil lines and the like.”
Klein breaks down the maintenance list with the following:
- Drives—Check the wear on V belts with a gauge. Also look for physical wear and glazing. Also check the V belt sheaves for wear due to slippage. Check sprocket wear on the chain drives. On the chain, look at the barrels of the links for wear. Measure 10 or 15 links to determine inside link wear. Check the fluid condition and level of reducers. Also look at the condition of their power cords.
- Aggregate Wear Surfaces—Here you’re looking at thickness. Look at the thickness of bins, feeders, chutes, hoppers, flights, drum shell, drag slats, silo batchers, discharge gates and cones.
- Plant Fluids—Not only will you look at fluid levels, but also look at their general condition. Are fluids gritty or is there water in the oil? You’ll want to perform fluid testing; get samples and send them out for analysis.
- Plant Air Systems—Is the ductwork in good condition or are there leaks or plugs of dust buildup? Send bag and dust samples for analysis to determine bag wear and expected life left to them. Check the seals in the drum for all aggregate inlet and outlet; also check dryer rotary seals.
- Plant Cords and Wires—Look for cuts or worn-out spots in cord coverings. Also look at cord and wire placement. Are they out of traffic, off the ground and or otherwise not in danger of getting hooked by equipment? It may be time to shore up the support of sagging wires.
The team at Kenco Engineering Inc., Roseville, California, also spelled out some of the areas plant managers and ground personnel tend to overlook. They called attention to RAP entry chutes, virgin material entry chutes and distribution flop gates at the top of the silos as examples of areas often ignored until it’s too late.
Brian Handshoe, vice president of operations for Kenco, explained that in each case, the reason these areas get ignored is due to their difficulty of access. “Since they are hard to access, the typical scenario is that the plant manager will continue running the plant until a large enough hole occurs to force the plant to shut down production,” Handshoe said. “The holes that occur create plant inefficiencies as well as lead to accelerated wear that makes the hole larger and larger until addressed.”
The way this mid-season wear is typically addressed, he lamented, is with short-term patching of the worn area or hole. “The temporary fix will last until it doesn’t, and the whole process repeats itself.”
He shared that the amount of time you can get out of the temporary fix will depend on how many tons per day you put through the drum and how abrasive the aggregate is. Getting wear spots shored up properly during the maintenance season is the less-stressful scenario.
Kenco’s Jim Alexander also highlighted the discharge ring as an area to double-check. “After speaking with multiple plant managers, the most common area they forget to check is the discharge ring,” Alexander shared. “They installed tungsten carbide (TC) discharge flights and didn’t look at the drum ring. They now use pieces of TC wear bar to protect the ring. The drum ring was being replaced annually, now the TC bars are checked annually and replaced approximately every three years. Most areas improve 3 to 5 times with TC strips in place.”
Alexander shared that, “Flop gates can be critical if they get a hole that goes unnoticed, they get contaminated product or unknown filling of an assumed empty silo. Other areas were also a result of extending primary wear problems such as recycle collar, flop gates, and chute transition points.”
No matter how the wear problems are creeping into your operation, performing a set of thorough inspections to find them before and after shutdown is the first step in preventing unplanned downtime next season. Make sure the areas the experts have listed for you here are added to your inspection map.
To contact the experts who assisted with this information:
Travis Sneed at BROCK
Steve Klein at Clarence Richard Company
Brian Handshoe and Jim Alexander at Kenco
Saving Downtime at the Belts
Those readers with quarry operations in addition to plant facilities may be interested in the Model DB belt rip detector, manufactured by Conveyor Components Company, which operates on a cable pull concept.
When a belt flap or tear—or a foreign obstruction such as a piece of rebar—has pierced a conveyor belt, the cable releases the activation ball from its protective socket and trips the device. The outputs of the Model DB can control up to four separate circuits, depending on the model chosen. These alarms can include one for machinery shutdown, which minimizes further conveyor belt damage, and one for alarm.
This standard housing construction is corrosion-resistant cast aluminum, with an optional polyester or black epoxy powder coating. The protective rubber boot on the cable assembly is designed to keep the activation mechanism clean.
For more information, contact Conveyor Components Company at (800) 233-3233.