For years, David Ridgeway has been searching for the perfect gunnite rig – one that could boost productivity and profitability as well as shoot the lighter-weight refractory that his company, Heater Fabricators of Tulsa, uses to insulate fired heaters and boilers at oil refineries and other industrial plants.
The president of the Tulsa, Okla.-based company finally found his ideal business-partner-on-wheels: the Dampcon rig made by the Blastcrete Equipment Co. in Anniston, Ala. Initially custom-designed for Heater Fabricators, the unit is now a member of the Blastcrete product line.
“The other three gunnite rigs we have are better suited for shooting heavier, coarser material than what we use, which is anywhere from 1,800-degree to 3,000-degree gunnite material,” says Ridgeway, whose company manufactures fired heaters and boilers for petrochemical plants around the world, as well as relines and reconditions older units. “So we were looking for a custom-built rig.”
KEEPING ENGINE CLEAN
The Dampcon predampening and gunning system, which predampens and spray-applies dry-process shotcrete material, features a 29-hp water-cooled Kubota diesel engine located toward the hitch-end of a tandem-axle flatbed trailer. (The machine is also available with a 30-hp electric motor and as a skid-mounted unit.) Ridgeway says that location is preferable to an engine based under the variable-speed conveyor belt that moves the dampened refractory into a hopper, also known as a rotary Piccola gun, which then forces the material through the hose for application.
“When the engine is under the conveyor, all the dirt and dribs and slop fall off the conveyor and clog up the radiators, which makes the engine run hot,” Ridgeway explains. “It tears up the engine.”
Another productivity benefit is the swing-out mixing chamber at the base of the conveyor, which allows easy access for cleaning the machine. Better cleaning results in improved machine longevity, he says.
“When you’re finished with a job, there’s a lot of debris laying there,” Ridgeway notes. “And if the chamber is fixed in place, someone has to crawl under and lay there while they chip off dried cement. It can take hours, but now our guys can do it in about 15 minutes because it’s so accessible. When you’re paying by the man-hour, that’s big.”
In addition, the 9-cubic-foot capacity, paddle-style mixing chamber is more than twice as big as most other units, which allows Heater Fabricators to run more product per hour. “I’d say we run a minimum of 30 percent more product per hour than before,” Ridgeway says. “On an average job, that ups our profit by about $4,000 per shift.”
Ridgeway also praises the durability of the unit, which the company purchased about a year ago. He says the rugged Kubota engine sometimes runs “wide open, 24/7,” for a month at a time.
A trolley system under the Piccola gun allows the unit to slide from under the end of the conveyor over to the engine for easier cleanup and maintenance. That also makes the unit easier to transport because it more evenly distributes the weight across the entire trailer, he says.
EASY TO USE
Ridgeway also points out the machine’s conveniently located controls, which allow an operator to stand on the ground and reach all critical controls from less than an arm’s length away.
Easy-to-reach controls are important because the gunnite material must be properly predampened before it reaches the Piccola gun. At the end of the hose, a nozzle operator adds more water to produce the correct consistency for spraying.
It takes three crewmembers to run the machine. One stands at the back and premixes the refractory material with water, making it just wet enough to flow up the conveyor and run through the hose. Another stands at the control panel and determines conveyor speed, and the nozzle operator applies the refractory.
“It’s not something that someone can just walk up and start doing,” Ridgeway says. “It’s a craft that takes years of experience to do well.”
Overall, Ridgeway says the Dampcon rig has become an indispensable tool for Heater Fabricators.
“This is our number one piece of equipment in that part of our business,” he says. “It’s the machine our operators always want to use. It’s extremely central to our operations.”
