Safety is a top-of-mind concern as it relates to ingredient handling. Following a number of events several years ago in which sugar dust led to explosions in refineries, OSHA and the National Fire Protection Association (NFPA) issued new regulations regarding dust in plants. Manufacturers of dry ingredient storage and handling equipment realize this is an issue they must address with their customers. However, no single solution exists when it comes to explosion mitigation.
In fact, while a lot of information on explosion mitigation is available, not many industry experts understand what is prudent for a plant and what is overkill, according to Scott Fisher, Shick USA, Kansas City, MO. “Do they know how to effectively address a concern without spending a lot of money but still address it and provide a safe working environment?” he asked rhetorically.
Although he pointed out that Shick is not necessarily the authority to address every concern, it does have access to industry experts who are able to guide the equipment manufacturer along the way. “We look at these systems and propose solutions to a customer based on the ingredient and how they use it,” he said. “In some cases, there is no requirement at all because of line size or how the company is moving the material around.”
To ensure that companies are meeting OSHA regulations, The Fred D. Pfening Co., Columbus, OH, offers surveys where members of its engineering department review systems for opportunities to improve safety. Ed Brackman, vice-president, sales, said that the company tries to offer the most cost-effective explosion mitigation solutions.
Horizon Systems, Lawrence, KS, also contracts with an individual who performs risk assessments at plants, and it also performs risk analysis for new facilities.
For systems that require explosion mitigation, Mr. Fisher said there are many things to discuss such as whether a company would require a passive or active system. A passive system may center on venting, so if an explosion would occur, it would follow a particular pathway, exiting the equipment and not affecting personnel or the plant. The explosion vent is the most common form of explosion protection, according to MAC Equipment, Kansas City, MO. In fact, the company’s NFPA-compliant Side Entry (Sentry) filters are designed so an explosion can be vented through the roof without increasing the cross-sectional area of the filter can, according to Stuart Carrico, food group manager, MAC. “This is a widely accepted and tested method and relatively inexpensive for the equipment it protects,” he added.
Venting is most cost-effective when the ingredient system is located near an outside wall, said Tom Leach, systems engineer, Horizon.
One of the first steps a bakery should take, according to Rod Harrison , sales manager, Northeast, Reimelt, Odessa, FL, is to have third-party testing of ingredients to determine if they are a risk, and then it must engage the equipment manufacturer to find the best option for mitigating the threat. He concurred that venting is generally the best first option.
Other passive options include fastacting isolation valves that shut within nanoseconds after a spark or fire is detected. Again, this isolates an explosion so it can’t go down a line and damage equipment or cause unsafe conditions, according to Mr. Fisher.
A more active system could fire off cannons of sodium bicarbonate or another fire suppressant in the event of a spark. Mr. Harris said this type of system deploys an inert powder that removes oxygen from the container. Another option that is rarely seen in bakeries, he added, is to use an inert gas such as nitrogen to transfer product, but this is generally too costly. KB Systems, Bangor, PA, offers an overfill protection design to its storage bins as a standard feature. “We prevent an otherwise recurring problem with flour trucks overfilling bulk material bins that could result in equipment damage and/or the release of potentially combustible dust,” said Karl Brunner, president, KB Systems. “We engineered an effective solution to this issue by equipping each bin with an automatic shutoff pinch valve at the loading station that prevents overfilling of the bins and clogging of the conveying lines. This saves our customers the hassle, expense and downtime of cleaning up a mess that is now preventable.”
Also, bakeries have a responsibility to understand which ingredients could have the potential for explosion, according to Mr. Fisher. Dust from materials such as sugar and flour can easily ignite if a spark is present, and NFPA gives dusts KSt values based on their explosibility. “KSt is a minimum ignition required to start a fire in a product,” Mr. Fisher said. “Anything above a 0 KSt has to be considered for explosion mitigation.
“This past year has not only been a learning experience but also has opened our eyes for what we are responsible for as equipment suppliers, and the things we need to help educate our customers about because they also have a lot of responsibility,” he continued.
While it is the responsibility of equipment manufacturers to supply systems that minimize the opportunity for a spark to occur, Mr. Fisher pointed out that it is the bakeries’ responsibility to provide a clean environment that would minimize a secondary event.
Although explosion mitigation is a primary concern, equipment manufacturers continue to focus on providing cost-effective systems to bakeries that are extremely accurate, with better controls, and are easier to clean and maintain.
Grain-based food manufacturers can save money buying ingredients in bulk. Not only do they receive price breaks on the cost of materials, but generally, these systems result in lower labor costs. KB Systems, which offers a wide selection of equipment for the storing, sifting, conveying and scaling of bulk ingredients, is widely known for its unique, custom-designed indoor storage systems, according to Mike Palmer, general manager, KB Systems. “These systems continue to offer very successful cost-effective solutions to help businesses meet the increased public demand for products that use ingredients such as whole-wheat flour,” he added.
The company was recently confronted with a project that featured severe space limitations when it installed a 210,000-lb bulk flour storage system at a noodle manufacturing plant in Brooklyn, NY. An outdoor silo simply was not an option at this location, according to James Toole, sales engineer, KB Systems, and the customer requested that any indoor storage be located in the basement of the facility, despite the fact that the basement ceiling was only 9 ft high. “We used our custom bin design expertise to develop a system that suited both its available space and capacity needs,” he said. “This design used otherwise nonproductive space in the building and allowed our customer to enjoy the cost savings associated with purchasing ingredients in bulk, as opposed to the more expensive individually packaged ingredients they used in the past.”
KB Systems’ square-frame design of its indoor bins, combined with a shallow-bottom discharge that features a positive ingredient flow air slide, allows its customers to store a large amount of bulk material in a relatively small space. “We design and manufacture custom bins to meet the needs of our clients’ often challenging applications,” Mr. Brunner added. “Our customers benefit from our expertise in designing ingredient handling systems to meet their capacity needs while fitting into very difficult locations without incurring additional expenses to modify their buildings.”
The solution installed at the noodle manufacturer included new storage tanks as well as stainless-steel weigh hoppers with modern Allen-Bradley PLC controls. KB Systems custom builds its weigh hoppers for each application for both pressure and vacuum conveying.
Esteve SAS, Rians, France, is also helping bakeries to save on operating costs with its automated ingredient handling systems, according to Philippe Jallet, director of marketing. The company recently installed a system that fully automates the handling of 30 ingredients, including micros and liquids at a sandwich bread and hamburger bun bakery that produces more than 66,000 tonnes annually on four lines.
The equipment doses ingredients in amounts ranging from 10 g to 350 kg, which are then automatically conveyed to one of three dough mixers via vacuum. The system serves as an accurate planning system for the bakery, offering easily available production information for better visibility and total budget control, according to Mr. Jallet. And it requires only one employee to control the mixing and ingredient feed operations, while improving quality through accuracy of ingredient delivery, he added.
Because labor is one of the highest costs in a plant, reducing man-hours is important and that is a primary benefit of a pneumatic conveying system, according to Doan Pendleton, vice-president, Vac-U-Max, Belleview, NJ. “Where numerous workers were previously required to manipulate material, there might now be the need for only one to add material at the front end of the process,” he said.
In the past year, Contemar Silo Systems, Concord, ON, Canada, supplied a pretzel manufacturer in the Dallas, TX, area with a complete turnkey bulk flour handling system. It features three 70,000-lb-capacity indoor flexible fabric silos that each store a different type of flour and a closed-loop pressure conveyance system to transfer each of the three flour types through a sifter and to a scaling hopper located in the production room, according to Kevin Rohwer, vice-president, Contemar.
The supplier uses silos manufactured by Walter Krause GmbH of Germany, which has built flexible fabric silos for more than 50 years. “These silos allow food manufacturers to move the storage of bulk ingredients indoors where more consistent temperature and levels of humidity can be achieved,” he said. “This completely removes the need and expense necessary to address condensation issues that are common with outdoor silos. In addition, the flexible nature of fabric silos reduces any chance of product bridging, or hanging up, within the silo.”
Another benefit of indoor storage is that the silos are located closer to the production area, reducing the cost of the conveying system by using smaller-sized blowers, according to Mr. Rohwer. “The unique features of our indoor flexible fabric silos allow us to design highquality bulk ingredient systems in a cost-effective manner, which ensures our customers the best ROI they can achieve,” he added.
The benefits of the automated ingredient handling system were numerous to the pretzel manufacturer, and one of the most obvious was the elimination of ingredient bags in the operation zone, according to Mr. Rohwer. “The reduction in the cost of the three types of flour is significant when it is purchased in bulk rather than in paper bags or even 2,000-lb-capacity totes for that matter,” he pointed out. “This reduced input cost can be directly applied to the equipment cost. Also, eliminating the handling of ingredient bags significantly reduces the workload on the manufacturer’s employees reducing or redirecting labor costs to other initiatives. These types of systems also make the employees’ jobs easier and safer by eliminating potential back injuries from the constant lifting of heavy ingredient bags.”
The system also improves product consistency because it “delivers accurate quantities of product and eliminates the possibility of human error that can arise when manually scaling ingredients,” according to Mr. Rohwer.
Because of the cost of raw materials, bakers want more accurate systems than they ever before, according to Mr. Fisher. “What accuracy really means to a customer is repeatability of quality and minimizing lost product,” he said. “If your accuracy is ±1% and you are always at 1%, that is lost product.”
Consequently, Shick is reviewing the individual components of its systems because some are more accurate than others. “We have to make sure we supply systems with better feed control and with intelligent control systems that monitor the current accuracy and are always hunting for the perfect zero, or zero tolerance. We write our control systems, so it always searches to get a perfect weightment. There is more focus on our process control systems that actually monitor and adjust those weighments from batch to batch to make sure that we are minimizing that bandwidth of tolerance that exists for dry and liquid ingredients.”
Eliminating possible human errors that can occur with hand weighing is a major driver for companies moving toward automated conveying of minor ingredients, according to Mr. Brackman. Accordingly, he said more companies are using bulk bag unloaders and bag dumps to automate minor ingredient handling. “Accuracy is always a big factor,” he added. “With some ingredients, being just a fraction of a pound off here or there could make a big difference with their doughs.”
Shick designs equipment with an eye on sanitation and cleaning. “That is not always easy to do with our business because of what we manufacture,” Mr. Fisher said. “We have a lot of horizontal surfaces. That is just the nature of our equipment, but we try to minimize those, and if we can’t minimize, we look at how to make them easily accessible for cleaning and maintenance.”
Vac-U-Max’s equipment can be taken apart without tools to allow them to be sanitized effi ciently and quickly, according to Mr. Pendleton. However, he also pointed out that pneumatic conveying reduces or eliminates downtime for maintenance and cleaning. “Pneumatic conveying systems require virtually no maintenance or cleaning because there are so few moving parts,” Mr. Pendleton added.
In addition, Shick has improved the preventive maintenance by better monitoring the individual components. “We are putting in systems to monitor that activity so we can better alert plant maintenance people when something should be lubricated or serviced,” Mr. Fisher said. “We are trying to provide better feedback from a controls standpoint that gives operators an understanding of what is going on and how they can correct it.”
The bottom line is that automated ingredient handling systems can help bakeries save money, through operating (reducing labor) and material (accuracy) costs. And equipment manufacturers are focused on safety to ensure that its systems will meet the latest regulations for explosion mitigation.