Posted by Control Concepts USA on | Comments Off on 5 Challenges of Bulk Material Handling
Bulk material handling equipment is designed to quickly move and process tons of material a day—and theoretically, requires minimal manual intervention.
In reality, many plant managers are plagued with material flow problems that slow down the entire process. Silos and hoppers get clogged, and workers have to stop everything they’re doing to hit them with a hammer. Material residue clings to ribbon blenders or mixers, and have to be flushed out with flour.
It’s tedious, time-consuming and can significantly affect productivity and costs. A cement company that had issues of shale hanging on the silo wall estimated that they lost $12,000 for every hour of downtime.
Even state-of-the-art equipment will run less efficiently if material isn’t flowing properly from one stage of the process to another. Here are some of the most common material handling problems, and how companies were able to solve them to get production back on track.
No flow/Poor flow
Material Flow problems can happen in practically any bulk material handling equipment, but there are three issues that are really common among silos and hoppers.
Material can form a stable arch over the outlet (bridging and arching), which can block material flow completely, or, it forms a stable open channel, but leaves stagnant material at the side (ratholing). According to Processing Magazine, “Ratholing can lead to erratic flow and reduce the bin’s live capacity by 90%.”
A material’s property can affect its tendency to form very cohesive arches, and how it responds to flow aids. Damp, moist and sticky materials will not respond to gentle aeration, and can even become more compact when vibrated or agitated.
AirSweep uses powerful air pulses which can lift even the most problematic materials.
Differences in particle size, density and chemistry can lead to material segregation. This becomes a problem in downstream processes, when the bulk solids need to have a uniform composition. If segregation isn’t addressed, it can affect the integrity of the formula, batch uniformity, package weights, and flowability.
Bulk powders that have poor flow properties such as fine-grained titanium dioxide—one of the commonly used nano-materials—have a tendency to segregate. A paint company used it in their new product formulation; the material would not completely empty out during the batch cycle, and it took 50 minutes to transport it a distance of 325 feet. Installing AirSweep VA-12 units effectively reduced batch time to 15 minutes.
Bulk material contamination
If equipment is not efficiently cleaned, stagnated material can contaminate any new materials that are loaded into it. This can affect the product quality—size, color, texture—and even its safety.
Material contamination can be a nightmare for food companies that have to recall products if there is any suspicion that their formula has been compromised. “The average cost of a recall to a food company is $10M in direct costs, in addition to brand damage and lost sales,” said Food&Safety Magazine, citing a joint industry study by the Food Marketing Institute and the Grocery Manufacturers Association.
A manufacturer of spices and flavorings used ribbon blenders to custom-blend ingredients. Their method of manually flushing with flour was labor-intensive and expensive, so they replaced them with AirSweep VA-12 Tri-Tri units. These not only completely cleaned the equipment, but could be conveniently removed without tools for frequent sanitizing.
Machine damage (and worker stress)
Hammering a vessel leaves dents and cracks, but even the strain of the material build up can cause structural stress.
The small cracks in the vessel can worsen over time, and even be aggravated by some kinds of material flow aids like agitators, vibrators, or air cannons. Eventually, the vessel will need to be repaired or even replaced.
Don’t discount the damage that these material flow aids can do to your workers, too. Bunge, an agribusiness and food ingredient company in the US, had issues of rice bran clumping in their hoppers and silos. “Workers had to hammer the vessels, which was ineffective and stressful for everyone in the factory. It was like fingernails on the chalkboard. You wanted to get away from it,” said John Pappenheim, Bunge’s Maintenance Manager.
AirSweep proved to be a more effective—and incredibly quiet—alternative. The air pulses lifted the rice bran back into the flow stream, and its faint hiss was further muffled by material in the vessel. Everyone in the plant could work in peace.
Barnes Concrete supplies ready-mix concrete to the Connecticut, New York, and New Jersey tri-state area. The feeder loads up to 250 tons of gravel per hour. Any equipment malfunction or failure in the production line could lead to an avalanche of material.
“It would be a train wreck [to be] buried with that amount of gravel,” said plant supervisor Joe Kruzewski. He estimates that it would take three people at least three hours to shovel one ton of gravel. “We would have to shovel for days!”
Material pile-ups can happen to any plant and any industry, and can be avoided with a very small and relatively inexpensive part: a DAZIC zero speed switch. It can be attached to the rotating shaft of any equipment to detect abnormal changes in speed. So if equipment is running too fast or too slow, it sends out an alarm so you can switch off the process before a pile up occurs.
What issues do you have with bulk material handing, and how can we help? Contact us and we’ll be happy to customize a proposal for you.
Posted by Control Concepts USA on | Comments Off on Zero Speed Switch: Protect Equipment, Process and People
A zero speed switch can help prevent material pileups and detect machine failure. Just like fire alarms, they are cheap, easy to install, and can quickly alert you of a problem and prevent thousands of dollars in damage.
What is a speed switch?
Speed switches are attached to rotating shafts to detect any abnormal change in rotation speed. These shafts are found in many types of plant machinery, from conveyor belts to rock crushers.
How do speed switches work?
Speed switches contain a non-contact inductive sensor probe positioned near the rotating object.
Small metal flags or magnets are mounted on a disc or pulser wrap, which generate pulses as they pass through the probe’s electromagnetic field. The pulses have a frequency proportional to the shaft RPM (rotations per minute).
This simple set-up can help detect any changes in speed. If the RPM does not match the speed trip-points that you have set – either it is moving too fast, too slowly, or stopped completely – a corresponding relay de-energizes and triggers an alarm.
To avoid nuisance tripping caused by normal pauses in speed (such as start-up or built-in time delays), the relay can be programmed to drop out only after a specified time. Some systems will need an external timer, while others can already have it built in.
Check out our video on DAZIC Speed Switches
How can a speed switch improve plant operations?
You can lose a whole day of productivity from shovelling material pile-up because an elevator or conveyor belt broke down. If the equipment breaks and the process stops, you’re paying your workers to sit around and do nothing, and essentially losing money.
Prevent wear and tear
Speed switches can prevent the misalignment of couplings, and stress/wear and tear of rollers and other small parts.
Detect machine damage before it becomes expensive to repair
Speed changes can be a sign that equipment needs repair or preventive maintenance. It’s cheaper to fix a small part now, than to replace equipment down the road.
Speed switches are sometimes used to initiate a secondary process once it reaches a particular speed or pre-programmed setting.
Prevent worker injury
The speed of operating equipment can play a big role in workplace safety. Speed switches can prevent accidents or injuries caused by malfunctioning equipment, spillage, or cleaning material pile-up.
Achieve accurate processes
Quality starts with precision. Keep your equipment running at the right speed and know the moment that there is a problem.
Where can I install a speed switch?
Speed switches can be installed on any device with a rotating shaft. This includes:
Belt, drag and screw conveyors
What industries use speed switches?
Some of the world’s biggest companies use speed switches for smoother, safer, and more efficient plant operations.
Grain, Feed & Milling
Bulk Materials Handling
Power Generation Plants
What are the different kinds of speed switches?
Zero speed switches differ in their set-up, features, performance specifications, mounting styles, and casings.
2-piece vs 3-piece system
Depending on your process, preferences, and considerations like space or the operating environment, you can opt for a two-piece system or a three-piece system.
A two-piece system only needs a speed switch and rotating target. A three-piece system has a speed switch, a rotating target, and a remotely mounted external sensor.
Electromechanical speed switches mechanically open or close a set of contacts
Electronic zero speed switches use a lay and electronic circuit
Magnetic proximity switches use a proximity sensor and a microcomputer
Some zero speed switches are designed for harsh outdoor conditions or hazardous plant environments. They can be weather-proof, dust-proof, and explosion-proof. To determine if the zero speed switch you need will meet your specifications look at the product’s National Electrical Manufacturers Association (NEMA) ratings.
Performance and features
Speed switch models cater to different shaft input speeds. Some perform better for applications that have slower start-ups or operating speeds, while others can detect not just when a shaft stops but begins to rotate backwards.
Switches need to be securely mounted and aligned to prevent damaging the bearings and causing premature product failure. Proper installation can include mounted brackets and couplings, internal flanges, or plug-in sockets with 8-pin termination.
Control Concepts, Inc. announced today the new RotoGuard® IV speed switches, an electronic speed switch device for sensing the reduction, increase, or loss in rotational motion associated with many types of moving equipment.
The RotoGuard IV is designed with an optical encoder and multi-toothed interrupter wheel to transform the rotation of the input shaft to voltage pulses. The unit can detect changes in motion between 1 and 400 RPM and provide a change of state, or alarm, when a variation in operating speed occurs. The RotoGuard IV may be directly coupled to another shaft or driven with a belt or chain.
“If one machine malfunctions, the RotoGuard switches can shut off the system to prevent further damage and delays that can cost thousands or even millions of dollars,” said Henry Tiffany III, president of Control Concepts, Inc.
The new RotoGuard IV features:
Solid state electronics
Universal Voltage Input
Startup delay (0-120 seconds)
Alarm delay (0-60 seconds)
Models available with NEMA 4/5 Rating (weatherproof and dust tight) or NEMA 7/9 Rating (Explosion Proof [EP models cannot exceed 100 RPM.])
Made in the USA
The RotoGuard® IV is available in four models ranging in price from $700 – $900. With a warranty of three years, these speed switches have one of the longest guarantees in the industry. See more about the new product here.
Since 1951, Control Concepts Inc. has helped solve material flow issues in plants around the world. We have tens of thousands of systems installed worldwide, and clients that include both S&P companies and SMEs. Our patented technologies are used in every industry because they are reliable, cost-effective, and have an amazing track record. We also have the longest warranties in the industry.
When you install a Control Concepts product, you can walk away and focus on other parts of the plant. Our AirSweep® bulk material activation system ensures on-demand material flow, AcoustiClean® Sonic Horns replaces manual material clearing, and DAZIC® and RotoGuard® Speed Switches prevent expensive equipment pileup.
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