FAQ's for the Bagging Equipment Industry

A valve bag is totally sealed on all sides prior to bag filling, except for an open, or “check valve” sleeve in a corner, to allow the introduction of material. Valve bags are an efficient means of filling and securely closing a flexible bag, to prevent the contents from leaking or sifting out, once the bag has been filled. Specialized filling machines are used to fill valve bags. During the filling process, an empty valve bag is deposited under the filling tube or spout of a valve bag filler. The spout penetrates the open valve of the bag, passing material through the tube, into the bag. After the bag is filled, the product inside the bag pushes the one-way valve closed, preventing leakage. Valve bags are commonly used to contain and transport dry powders and granular products like cement, concrete, minerals, chemicals, seeds, grains, and fertilizers. Valve bags are constructed of a variety of materials including paper, plastic film, and plastic woven mesh.

An open mouth bag has one open end through which product is emptied through a large, throated spout. Open mouth bags package virtually any type of product and are filled with specialized filling machines. Filling and sealing open-mouth bags is a two-step process. The open end of an empty, open mouth bag is placed under the filling spout of an open mouth bag filler. The spout is clamped inside the bag’s open to prevent product spillage. After the bag is filled, it is sealed or closed, with a hot melt glue sealer, plastic bag sealer, or bag sewing machine. Open mouth bags are commonly used to contain and transport dry powders and granular products like food, chemicals, seeds, grains, fertilizers, and landscaping products. Open mouth bags are constructed of a variety of materials including paper, plastic film, and plastic woven mesh.

Gross weigh fillers simultaneously fill and weigh bags, boxes, or drums with the dry bulk product, and are available in open mouth, valve bag, and big bag filler styles. The different styles of gross weighing fillers include gravity, pneumatic, auger, impeller, vibratory and belt-fed models, utilizing balance scale beam or electronic load-cell technology to efficiently and accurately meter dry bulk products. Gross weigh fillers easily control fine powders, granular materials, chunks, and pieces. A single gross weigh filler can handle a maximum of 8 bags per minute, although multiple gross weigh fillers can be paired, achieve higher production rates. Product flow characteristics, the bags used, and other conditions specific to the plant environment can heavily influence the actual production rate achieved.

Net weigh fillers pre-weigh dose charges of product into a scaled weigh hopper, before delivering it into the bag. This method of bag filling is typically more weight accurate than most gross weigh fillers. Net weigh fillers are available in open mouth, valve bag and big bag fillers, in styles including gravity, pneumatic, auger, vibratory and belt-fed, efficiently and accurately metering dry bulk products like fine powders, granular materials, chunks and pieces, into bags. A single net weigh filler fills a maximum of 25 bags per minute. Product flow characteristics, the bags used, and other conditions specific to the plant environment can heavily influence the actual production rate achieved.

Mechanical weighing scales are basic, simple, and easy to use. Mechanical weighing scales shift reliance away from human labor, and to technology, for more accurate weigh, every time. Mechanical weighing scales are easy to set up and adjust and require little operator training. Typically, mechanical weighing scales have three controls: a start button, a stop button, and a weight hanger or slide, which you adjust using weights. Mechanical weighing scales are easy to troubleshoot and repair, and can typically be serviced by an in-house maintenance person. They are also more economical to maintain than digital weighing scales. Finally, Mechanical weighing scales are not nearly as susceptible to damage (computer components) blackouts, brownouts, power surges, or electrical storms.

Mechanical weighing scales have three disadvantages. Zeroing in on an exact target weight with a mechanical weighing scale can be a process of trial and error. If you are filling multiple bag weights from the same machine, this process becomes even more complex. Mechanical weighing scales are not “intelligent,” and do not know (give no indication) if the rate of product flow is changing or drifting off the target weight. As it does not make automatic adjustments, an average weight accuracy of +/- 1% is required, and periodic scale checks or “check weighing” may be required. Mechanical weighing scales have no way to transmit or record “real-time” data, or even the most basic production information, including bag weights and total unit production. Choosing a mechanical weighing scale means you must carefully consider who will be responsible for operating it, and what products you are using.

Digital weighing scales are typically more weight accurate, providing the operator useful feedback. They are also more precise, with a lower reject rate than mechanical scales (2%). Microprocessor controls display each final fill weight, giving the system operator instant feedback on weighing accurately.  They also track and adjust the cutoff point of the filler, to compensate for changes in bulk density and product flow rates, on the fly.  Digital weighing scales provide diagnostic tools, automatic flow rate tracking, and auto-correction for changes in flow rates or bulk density, and typically reduce overall maintenance costs.

Digital weighing scales require a greater amount of training and skill to operate than a typical mechanical weighing scale. In applications where high employee turnover is frequent, operator training becomes a continuing necessity. Even though infrequent, if there are problems with a digital scale, it might challenge in-house maintenance personnel skills.

Used equipment is sold “as is, where is,” on a cash basis, with no guaranty or warranty. In most cases, CBE used equipment is raw surplus machinery, and in nearly every case, equipment is in operable condition. CBE strives to provide honest and accurate information regarding the features and conditions of the equipment, through quality pictures and descriptions provided by the seller. However, we want to reiterate that all packaging equipment sold as used is “as is, where is,” with no guaranty or warranty. 

Rebuilt Equipment is sold in “good operating condition,” on a cash basis, with a 30-day guaranty on all parts and components. Rebuilt equipment has been thoroughly serviced with normal wear parts inspected and repaired or replaced, as needed. In most cases, CBE used equipment is raw surplus machinery, and in nearly every case, equipment is in operable condition. CBE strives to provide honest and accurate information regarding the features and conditions of the equipment, through quality pictures and descriptions provided by the seller.  Our guaranty covers components only, and all replacements will be sent via UPS Ground or Common Carrier, at the sole discretion of CBE, Ltd. 

Reconditioned Equipment: All reconditioned packaging equipment has been completely disassembled, sandblasted, and repainted. All motors, motor control panels, air cylinders, pneumatic control valves, hoses, fittings, etc. are replaced with new components unless otherwise specified. The machines are supplied with operations manuals, complete with wiring schematics and replacement parts pages, and in most cases, CBE can provide support for our reconditioned equipment. All reconditioned machines include a limited warranty that covers failure of components for 180 days from the date of shipment, from our Taylor, TX facility. 

The type of automatic bagging machine is specific to the customer. CBE provides a range of fully automated systems, for which you can expect to pay in the mid-to-high five-figure range or more.

Pricing depends on the products, speed, bag styles, sizes, and the complexity of the packaging. The more complex or high-speed the packaging process is, the more expensive the equipment will be.

Most CBE equipment does not require advanced technical knowledge to operate. Modern packing machines can even be changed quickly to accommodate different bags, without tools.  The more automated your equipment, the easier it will be to use.

A fully automatic packaging system is best for high speeds and minimal human interaction, in situations that produce many products with relatively low variation. A fully automated line includes tools to feed the product to the system, a scale, and an automatic bagging machine. Automated systems are known for accuracy and consistency but require a large upfront investment.

A semi-automatic packaging system requires reliance on human labor, using an automated scale to weigh the product, but a human technician to dispense the product into bags and seal them. Semi-automatic packaging lines are a good first-solution, as individual machinery can be integrated later to create a fully automated system. Semi-automatic packaging lines are less expensive, but also less accurate and slower than fully automated systems.

Adjusting an automatic bagger machine to accommodate different bags is called changeover, and is usually a fast process. Consider automating different parts of the process to further simplify your production line. If you find you need a system with further automation, you may want to invest in more automated equipment.

Automatic bagging machines measure quantities of product into the packaging machine to be dispensed into the bags. Fillers usually sit above or off to the side of the packaging machine. An automatic bagging machine is best for companies hoping to incorporate more uniformity and ease of production into their environment.

Packaging equipment speeds are usually represented by bags per minute (BPM), and are often rated for a maximum number of bags per minute. Automated bagging machines can be rated from 30 – 300 bags per minute. Your product, bag sizes and styles, plant environment, and technical skill of operators will all factor in to the speed.