Concrete Products covers the issues that attract producers of ready mixed and manufactured concrete focusing on equipment and material technology, market development and management topics.
Issue link: http://concrete.epubxp.com/i/538423
92 • July 2015 www.concreteproducts.com INNOVATIONS REPORT MIXERS seriously, noting: "We wanted long-term yield and excellent blend. We specifed stainless steel for the blenders since we didn't want a porous material when working with pigments. We also thought that stainless would help with cleanup. And we chose rotary over a rib- bon-style blender because it reportedly offers fve times more life." Each Rotary Batch Mixer consists of a horizontal rotating drum with a stationary inlet and outlet at opposite ends. As the drum rotates, internal mixing fights and lifters tumble, fold, cut and turn the material in a multidirectional manner. The gravity-driven pro- cess produces a uniform mix in two minutes, regardless of the differ- ence in ingredients' bulk densities. The lifters in the continuously rotating drum elevate the mate- rial, preventing segregation of the batch upon discharge through the stationary plug gate valve, as well as promote total evacuation with no residual. Kingdom's 50-cu.-ft. mixer includes an optional Intensifer—critical to homogenous blending of pigments through- out a batch of cement. Since the Rotary Batch Mixer is engineered specifcally to blend without degrading particles, the Intensifer can be activated as needed to impart shear into the batch to break apart agglomerated pigments and other non-free-fowing materials into discrete particles. As the drum rotates, specially designed baffes at the inlet end direct all batch materials through the high energy zone of the Intensifer several times, assuring uniform distribution. FROM SILO TO BAG Kingdom blends four to six batches per day. "We use different grades of quartz sand aggregate (from 100, 200, and 325 mesh all the way up to 5/16-in. and 3/8-in. chunk rock). The finest is down in the silicate flour range," explains Sacco. The company also runs a variety of addi- tives such as pigments and plasticizers. "On average, we manufacture 35 to 40 different colors in hardeners alone," plus a huge variety of con- crete restoration products, glass fiber reinforced concrete and plaster mixes, along with sculpting clay blends. "We are perfectly set up for whatever precision toll blending tasks that are required of us," he says. Raw materials arrive in tankers and are stored in fve silos in- side the Kingdom Products facility. Three are flled with U.S. Silica fne, medium, and coarse grades of crushed quartz; the other two Essroc Cement Type I and Federal White Portland. "By keeping the silos inside and maintaining consistent temperature throughout our facility utilizing radiant foor heating, we control the humidity in our dry goods," explains Sacco. "I built our entire facility to suit the blending operation, even having our silos custom manufactured to ft inside the building. Everything in my blending operation has been specifed to be manufactured in the USA and was one of my requirements in the purchase of our equipment." From each silo an auger conveyor feeds material through a col- lection hopper and into a tote resting on a weigh station. "That way, if we have a problem with too much sand or too much portland cement, we have control over it," Sacco adds. Totes are moved via forklift to the blending station where the material is introduced into the mixer. Additive mixtures, including pigments, are then added and run through customized blend cycle operations to reach a fnal product. Some products require a gentle blend while others require a more aggressive cycle. "Once we've blended thoroughly, we do our quality control check through an inspection port welded into the machine. Then we discharge into a tote and move it to our fnished goods station," says Sacco. "Using an air packer, we can package the end product in anything from pails, buckets, bags, etc." Typically, Kingdom's products are packed in 50- to 60-lb. bags or 5-gal. pails. Cleanup is minimal. "We only run dry materials," notes Sacco. "In fact, our blender never sees water. Between batches, we brush everything down inside, and vacuum it out with a HEPA vacuum." PERFECTING THE FORMULA Many of Kingdom's new formulations are market driven. "We have developed good communication with installers using our products in the field in order to get feedback about what they want in product performance," explains Sacco. "Whether it's a finer aggregate or a lon- ger open time, we can adjust the additive mixture to give our custom- ers the products they want." For instance, the company recently introduced a vertical stamp mix. "Some of our customers wanted a material with improved adhe- sive strength—something that would cling better and wouldn't dry out as quickly," he says. "All of our formulas are developed by myself or my brother Jim. When we develop the new formulation, we frst run it in our lab blender, which is a 3-cu.-ft. Munson Mini Mixer. It's equipped with the same Intensifer, and represents what we will get on the larger blender." New formulations are ramped up using the Mini Mixer from a few hundred grams to a few hundred pounds (used for feld and other testing) before production moves to the 50-cu.-ft. mixer to produce 4,500-lb. batches, or the 40-cu.-ft. mixer to produce 3,000- lb. batches. EXPANSION ON THE HORIZON With plans to expand Kingdom Products' toll manufacturing opera- tions, Sacco purchased the used 40-cu.-ft. Munson Rotary Batch Mixer. "Even though it had been sitting outside for more than two years, the mechanics exhibited no wear," he says. "We reconditioned it, repainted the framework, put in new seals, and installed it in January Jim Sacco takes batch samples from inspec- tion port for quality assurance checks. The mixer yields uniform blends in two min- utes with no segregation of ingredients regardless of different bulk densities. The cage-style Intensifer at the inlet end of the mixer creates a high energy zone, assuring homogenous blends. Kingdom Products de- velops and tests new mix designs with its 3-cu.-ft. capacity Munson Mini Mixer.