Bulk powder handling insights

• Automation in bulk powder handling enhances worker safety by reducing musculoskeletal disorders, inhalation hazards and the risk of combustible dust explosions, minimizing direct and indirect costs.
• Automated powder handling not only improves operational safety and consumer confidence but also boosts productivity, quality control and inventory management.

Bulk powders are used at some stage in almost every industry: food, pharmaceutical, confectionary, chemical, plastics, aerospace, nutraceutical, packaging, additive manufacturing (3-D printing), and energetics. Even liquid end-products will have powdered ingredients that give those liquids an identity or function: sports and energy drinks, alcohol, soups and sauces, lubricants, and paint.

However, powder handling means different things to every company, generally based on the volume and type of powders they introduce to their manufacturing process or the ultimate end-product which is in the form of a powder.

Small family-owned businesses and the largest companies in the world, as well as government-owned facilities, have different concepts of “bulk powder handling”. Some focus on the “bulk” part: They have powders supplied in non-consumer-sized containers such as 50-lb. bags, 55-gal. drums, 2,000-lb. bulk bags or supplied from silos.

Others focus on the “handling” part, which is an engineered process with equipment to transport the product from point A to point B.

Figure 1: Vacuum conveying allows change from manual bag dumping to bulk bags for lower cost of materials. Courtesy: VAC-U-MAX

Five reasons to consider automation for bulk powder handling

The benefits of automating the bulk powder handling process will provide varying benefits depending on the user’s perspective, but there are several that will often come to the forefront.

1. Improved worker health

Manual container dumping or filling of bulk powders can be a repetitive, physically demanding, and mind-numbing activity that leads to musculoskeletal disorders, which the Bureau of Labor Statistics of the Department of Labor defines as “musculoskeletal system and connective tissue diseases and disorders when the event or exposure leading to the case is bodily reaction (e.g., bending, climbing, crawling, reaching, twisting), overexertion, or repetitive motion, from bending, twisting, pushing, pulling…

National Safety Council data shows the average (direct) worker’s compensation costs of a lower back injury was almost $40,000 in 2021, arms/shoulders at $50,000 and hip/thigh/pelvis injuries at almost $60,000. That’s not counting the indirect costs, which can be several times greater than the direct costs. Indirect costs can include lost time, increased worker’s compensation insurance premiums, recruiting costs or repositioning a substitute worker, new worker training, slower productivity of replacement worker and more. Vacuum-assisted lifting devices also can reduce repetitive motion tasks when they’re part of a vacuum conveying system. Vacuuming materials from drums or bulk bags also helps reduce heavy-lifting and lower-back strains.

Figure 2: Bag dump station includes vacuum-assisted lifting to reduce exertion and reduce bending/twisting tasks. Courtesy: VAC-U-MAX

Personnel also need to be safe from inhalation hazards from fugitive dusts. Manual dumping and filling can expose workers to allergens such as sesame seed dust and milk powders. Other powders such as super-absorbent polymer (SAP) will dry out mucous membranes in the eyes and nose of workers if over-exposed. Workers in certain industries can be exposed to carcinogenic materials such as silica sand through inhalation.

Automation via vacuum conveying of these powders in lieu of manual handling reduce fugitive dusts and unhealthy or life-threatening exposures.

However, if bag dumping cannot be avoided, devices such as bag dump stations with integral dust collectors at the entry point of a vacuum conveying system will draw dusts away from the worker when dumping bags of powder.

Workers also are at risk in combustible dust environments. Despite the known dangers of combustible dust explosions, workers continue to be injured or killed in plant environments with poor dust control and lax housekeeping which often result from manual powder handling operations and lack of automation of the powder handling tasks.

Figure 3: Vacuum conveyor keeps auger-filler packaging machine full with constant head pressure of powder for accurate filled containers. Courtesy: VAC-U-MAX

2. Better operations safety

Most organic materials and many non-organic materials such as plastics will be found to be combustible when in powder form. Manual filling of process equipment will result in accumulations of fugitive dust on floors, machine surfaces, walls and overhead building structures. These conditions make a facility ripe for a combustible dust explosion if an ignition source such as static electricity discharge or an overheated bearing is initiated. NFPA standards regarding combustible dust, and OSHA’s enforcement of the standards are focused on life safety and continuing operations by preventing dust accumulations and conditions that lead to catastrophic combustible dust events. Powder handling automation with an enclosed vacuum conveying system will reduce, if not eliminate, fugitive dusts escaping into the plant environment. It has been said in hazard and operability (HAZOP) evaluations that “training is not an acceptable safety device.” The possibility of human error remains and automation via vacuum powder conveying is suitable as an engineering control and a device that reduces the chances of operator error.

Figure 4: Vacuum conveyor with discharge-on-demand sequencing allows highest accuracy from gravimetric feeders. Courtesy: VAC-U-MAX

3. Greater consumer safety

The enclosed nature of a vacuum conveying system will prevent opportunities for accidental or intentional contamination of the ingredient stream. Food and pharma products, nutritional and cosmetic products and the like have increased risk of recall or injury from contamination if their powder handling process has gaps due to manual handling. Again, vacuum conveying of powders will protect product and brand integrity and maximize consumer safety and confidence.

Figure 5: Vacuum conveyor keeps stick-pack machine full and eliminates ladder climbing and manual container dumping. Courtesy: VAC-U-MAX

4. Improved quality control

Contamination and inconsistent delivery of powders into a manufacturing process will ruin quality control plans. Automation of powder handling via vacuum conveying, or specifically batch weighing vacuum systems, will deliver consistent and unadulterated finished product. Recipes can be accurately followed and ingredients are not wasted. Segregation of allergen-containing products is best accomplished with an enclosed vacuum conveying system. Enclosed vacuum conveying systems reduce the chance of pest infiltration as well. Packaging equipment such as auger fillers require consistent feed of powders in the packaging machine supply hopper. An automated vacuum conveyor maintains the consistent “head pressure” to make the auger filler perform at its best.

Other powder processing equipment such as loss-in-weight (LIW or gravimetric) feeders are most accurate when the refill time is minimized. Gravimetric feeders convert into volumetric (non-weighing) mode during its fill cycle. Minimizing the refill time maximizes the accuracy of a gravimetric feeder.

Figure 6: Vacuum conveyor technique known as direct-charge blender loading keeps ingredients at floor level and eliminates stair climbing and forklift traffic. Courtesy: VAC-U-MAX

A vacuum conveyor accomplishes this by holding the next batch of powder waiting for the refill signal from the feeder and immediately discharging the powder. This is known as discharge-on-demand and is a form of immediate gratification in the bulk powder handling industry.

5. Increased worker productivity

Manual handling of bulk powders can work until the need for increased throughput outpaces the human body’s ability to keep up. Automated powder handling can take a production rate to the next level and not be limited by the human’s physiology. Today’s powder packaging lines can demand up to 10,000 lb. (4,500 kg) of powder per hour. Workers cannot climb ladders and dump boxes fast enough to meet that rate. Automation via vacuum conveying is the best answer to refilling today’s bottling lines, stick-pack fillers and vertical form-fill-seal (VFFS) machines.

Productivity is also improved when time-consuming steps are removed and replaced with higher-output solutions like automated powder handling. Many powder handling operations require forklifts and operators in production suites to raise pallets of bags up to mezzanine level. Automation via vacuum conveying can eliminate the forklift tasks and laborer from the process time allocation.

Figure 7: Vacuum conveyor loads a mixing tank effortlessly from a bulk bag instead of hand dumping 3,000lbs of sugar from 50-lb bags. Courtesy: VAC-U-MAX

Ingredients can stay on the ground floor and forklifts can stay outside of the production suite thus saving time and space. Automated powder handling such as direct-charge blender loading not only reduces material handling via forklift, but it also stops workers from climbing on mezzanines to dump those bags into tumble blenders.

Automation of bulk powder handling can make other process equipment perform better. A vacuum conveying system can increase the throughput of batch equipment such as rotary blenders and ribbon blenders by staging ingredients above the blenders/mixers for immediate filling when the previous batch is completed. Automation cannot shorten the mixing process, but it can shorten the loading and unloading times to complete more batches in a day.

Figure 8: Automated powder handling can begin with bulk bag unloading for lower ingredient costs and better dust control. Courtesy: VAC-U-MAX

The current and foreseeable labor shortage can also be solved with automation of powder handling tasks. Seasonal increases, or long-term production increases are accommodated using vacuum conveying or powders. Vacuum conveyors won’t complain about repetitive tasks, and they don’t take vacations, and they help achieve higher output goals when new hires are in short supply.

Automated bulk powder handling increases productivity, reduces potential costs and liabilities from employee workplace injuries, ensures ongoing operations in a safe plant environment, reduces the risk of product recalls, and builds consistent brand strength, provides better inventory management and reduces product loss.

Figure 9: Volumetric and gravimetric feeders are big beneficiaries of automated vacuum conveying for refill. Courtesy: VAC-U-MAX

It also can reduce ingredient costs by transitioning from smaller manually dumped containers to larger bulk material containers such as bulk bags and silos. Vacuum conveying is the only bulk powder handling technology that is “container agnostic” and works with any original ingredient container.

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