Baler Machines

Chapter 1: What is a Baler?

A baler is a piece of equipment used to compress solid industrial waste or recyclable materials (e.g., paper, plastic, foam, cans, etc.) to achieve better material handling and storage. Eliminating empty space between individual items of these bulk products is a great way to save costs attributed to storage and transport.

Agricultural products and wastes are baled not just for space reduction, but to aid in preserving its intrinsic value. Animal fodders are products such as hay, grass, and straw used for feeding domesticated livestock instead of foraging. Aside from being bulky, animal fodder can easily decompose. Desired qualities of animal fodder are high amounts of energy and protein to meet the nutritional needs of the farmed livestock. This is compromised by drying and molding. Moreover, as the fodder spoils, heat is generated which can cause spontaneous combustion.

Baling helps control the moisture content of the fodder. Too little moisture causes hay to become dry and lose its nutritional value; too much can cause spoilage and in turn, combustion. Baled animal fodders are usually wrapped in plastic sheets or covers to help with moisture retention.

Industrial balers improve material handling of items mostly used for recycling facilities. Balers make the materials smaller, denser, heavier, and stackable. This improves the efficiency of hauling the items producing large economic benefits. On top of that, recycling baled products significantly improves throughput rates due to easier feeding. This results in reduced operating costs.

Chapter 2: History of Balers

Balers were first introduced in the 1930s to help farmers manage the size of haystacks. Before automatic balers, hay was cut manually and gathered into haystacks using rakes and forks. As mentioned earlier, it was already recognized that there is an optimal size for a haystack. It must not be too large to promote heating and combustion, nor too small which can promote drying and degradation.

The first automatic balers were round balers called Roto-Balers, launched in 1947 by Allis Chalmers. Other types of balers also emerged such as the rectangular and small square balers. Both are used for agriculture.

Early scrap material balers were in the form of compactors patented by MS Wells in 1941 as a means for compacting oil cans. Come 1970s, these were further developed to compact household wastes by using hydraulic pressure from water lines.

Chapter 3: Types of Balers

Balers are chosen depending on the type of material to be baled, material loading methods, required purity, required dimensions for transport and milling, and throughput. Since the main point of using balers is to produce an economical advantage, it is important to keep in mind the difference between the baler’s investment and operating costs against the savings produced from storage and transportation cost reductions. Selecting a large, high throughput baling machine may not be the best way to go. There are many baling machines available in the market that serve a particular range of materials and specifications.

• Vertical Balers:

  As the name suggests, this type of baler compresses materials by using a vertical, downward force. Vertical balers are sometimes referred to as downstroke balers. These machines are usually used for recycling cardboard, plastics, metals, and foam. The compression chamber is located at the side of the machine at an elevated position. Compression is provided by the ram which is actuated either by hydraulics or by an electric motor. Once the chamber is filled, the ram moves downward which crushes the materials. However, the downside is that their output is not mill standard due to less available compaction force and inconsistent sizes. Inconsistent density and sizes make bales inefficient to transport. Also, this adds additional processing steps to the recycling mill making them difficult to sell. Some manufacturers offer heavy-duty vertical balers that have powerful pistons actuated by high-power reciprocating pumps. Their robust construction allows them to compact scraps into dense, standard size bales.

  

  
  

  Vertical balers take up less space than horizontal balers. Because of this, they are practical to use for small scale applications such as supermarkets and retail stores. Their construction is more compact making them less expensive. Their cost tends to be a fraction of the price of a horizontal baler. When it comes to the variety of materials processed, vertical balers have the advantage since they can process almost all types of recyclable materials. The downside, however, is that their output is not mill standard due to less compaction force available and inconsistent sizes. Inconsistent density and sizes make bales inefficient to transport. Also, this adds additional processing steps to the recycling mill making them difficult to sell.

• Horizontal Balers:

  This type uses horizontal force to compress the materials. Unlike vertical balers, the materials are not loaded directly into the chamber but are collected by a hopper on top of the machine. Conveyor, sorting, and shredding systems may also be integrated to aid in loading, making them more convenient and less labor-intensive to operate. Horizontal balers are usually larger than vertical ones, enabling them to process high volumes. Larger forces are also available, producing denser bales that can weigh up to half a ton. Moreover, horizontal balers produce uniform size bales making them more suitable for transport and processing.

  

  
  

• Single Ram Balers:

  Single ram balers produce compression using a single hydraulic cylinder. This is the most common type of balers used for material recycling. This type can be horizontal or vertical, depending on the orientation of the ram. Horizontal, single ram balers can be divided further into closed-end and open-end extrusion balers.

  • Closed-end (closed-door) balers

    Closed-end (closed-door) balers compact material using a single ram against the chamber door. After compaction, a chamber door opens to release the bale. Automatic ejection rams are also added to aid in releasing the compacted bale.

    

    
    

  • Open-end extrusion baler

    Open-end extrusion baler compresses the materials through a long extrusion chamber. This is often called continuous horizontal baling. The ram compresses the bale against the side of the previous bale formed in the extrusion chamber. This process is faster than closed-end balers which also eliminates the need for other parts such as ejection rams and separation doors. Moreover, a common feature of open-end extrusion balers is their automatic tying mechanism. This is particularly useful for high rebound products such as cardboard and textiles.

• Two Ram Balers:

  Two ram balers, also known as two-cylinder balers, are baling machines that compress material using two hydraulic cylinders. Like the single ram balers, these can be vertical or horizontal in orientation. Two ram balers usually produce denser bales than single ram balers. These machines are more suitable for compacting high rebound materials such as rubber. Hard to bale materials sometimes needed additional processes such as shredding or addition of material conditioners. These add cost to the baling process. Moreover, additional processes mean more possible bottlenecks that may affect throughput.

  

  
  

  Another common configuration of two-ram balers is the L-shape, where the material is compressed in one axis. And after this initial compression, it is then compressed in the other axis. Since the two-ram baler opening is not limited by the bale width, they can have a larger feed opening for more convenient loading. For bulkier materials, a larger opening allows for a higher rate of loading while lessening the chances of material bridging in the hopper.

  

  
  

  Another advantage of two ram balers is less tie wire usage. By producing a denser bale, less amount of wire is required to secure the shape of the material. Since compacting more materials and exerting more pressure forces materials to undergo plastic deformation wherein the material will not retain its original shape, two-ram balers produce bales that do not change their dimensions over time. In turn, the bales produced do not require stronger ties.

• Liquid Extraction Balers:

  As the name suggests, liquid extraction balers not only compact materials but also drain liquid from them. This capability is particularly useful for baling rejects from food, bottled, and brewed goods production. The main difference between liquid extraction balers from other types are the materials used for their construction. Almost 90% of their structural parts are made from stainless steel, while the rest are coated with anti-wear and corrosion paint. This is to prevent the liquid from degrading the parts of the baler. Also, liquid extraction balers feature a closed-loop catch system that captures the extracted liquid. This allows the clean and efficient liquid collection and discharge.

• Ferrous Balers:

  These types are mostly used in scrap metal processing. These consist of two or three rams that are designed to handle heavy materials like metals. The two-cylinder ferrous baler consists of a pressing lid or a wing door that compresses the metals along with the main ram. The three-cylinder ferrous baler, on the other hand, compresses the metals in all directions. A pressing lid pre-compresses the metals to the desired baler dimension, while the other two rams compress the material similar to how an L-shaped, two-ram baler operates.

  

  
  

  Like two-ram balers, ferrous balers have large openings to allow feeding more material. The openings are not limited by the dimensions of the bales produced. Material feeding is usually done by cranes.

  Another characteristic of ferrous balers is that they do not use automatic tying. Since metals plastically deform when compressed, they mostly retain their shape after compaction.

• Shear/Baler/Logger or SBL:

  In this machine, the materials are compressed to form a log shape compacted material which is then cut to length by shearing or compacted further by another compression forming a bale. The “logging” action acts like a pre-pressing operation. Since these machines produce sheared logs aside from high-density bales, SBLs are also called scrap shears.

  

  
  

  The main advantage of SBLs is its portability. Most SBLs are transported by trailer trucks and are equipped with hydraulic landing gears enabling the machine to be easily mounted onsite. This is useful in small junkyards, demolition projects, and site cleanup activities.

• Round Baler or Tractor Baler:

  This type of baler is used for baling agricultural products. Round balers are usually pulled by a tractor which collects forage through the field. As the tractor gathers the forage, these are conveyed into the baling chamber where a series of rollers and belts roll the materials. When the required density and dimensions are reached, an automatic wrapping mechanism is triggered which wraps the rolled material in mesh netting. After wrapping, the baler opens and releases the round bale.

Chapter 4: Baler Parts and Accessories

A simple baler consists of a ram, chamber, gate for material feeding, and a machine to produce compressive force. These basic parts are then modified and improved to increase the compressive forces and throughput of the machine. Accessories and other machines such as hoppers and wire tying mechanisms are also integrated to eliminate manual labor. Below are the common parts of a baling machine.

• Hydraulic Cylinder:

  This part exerts the required force to compress the material. The working fluid is pressurized by positive displacement pumps to achieve the required compression. Scrap metal baling requires the construction of hydraulic cylinders to be tough and durable. Hydraulic cylinders must be able to withstand shocks and side loading. Proper maintenance is essential such as condition monitoring and lubricating.

  

  
  

• Ram:

  Attached to the hydraulic cylinder is the ram. The ram is the part that presses against the material.

• Hydraulic System:

  This includes pumps, hoses, fittings, and valves. The hydraulic system supplies the required actuation of the cylinders. Since these parts are subjected to dynamic loads, they require consistent maintenance and need to be replaced due to wear and tear over time.

• Oil Filter:

  The oil filter maintains the cleanliness of the hydraulic system. As the oil ages, deposits may form that can damage the hydraulic fittings and pumps. Oil filters are regularly changed as suggested by the manufacturer’s specification.

• Motors and Other Electrical Components:

  This includes motors, wires, conduits, and cooling fans. The motor drives the pump, usually coupled by a gearbox.

• Proximity Switches and Other Types of Sensors:

  Sensors may include proximity switches, photo-eyes, limit switches, or linear potentiometers. These detect the movement of the bales or the relative position of the machine parts. This enables the baler to operate automatically.

• Control System:

  This is where commands are entered by the operator. The hydraulic system is usually controlled by programmable logic circuits or PLCs by manipulating the opening and closing of the valves. This is also where parameters such as pressure, bale dimensions, and temperature are monitored. For advanced systems, the machine is equipped with diagnostic and fault detection systems.

  

  
  

• Bale Chamber:

  The bale chamber encloses and shapes the bale. Bale chambers are made of thick steel that can withstand pressures acted by the compression of the material. Agricultural balers use variable chambers, enabling them to produce bales with more consistent densities. In contrast with industrial baler chambers, variable chambers are a completely different design that uses tensioning belts.

• Hopper:

  Hoppers aid in the collection of materials for baling. This part also increases the area of the chamber opening so more materials can be fed.

• Conveyors:

  Conveyors are used for material feeding at a lower elevation. This eliminates the need for larger cranes that are usually needed to reach the height of the hopper. Loader trucks dump the materials onto the conveyor which lifts and transports the material into the hopper.

  

  
  

• Pressing Lid:

  This part is present in ferrous balers. The pressing lid acts as a pre-compression ram upon closing. After achieving the desired pre-compression, the pressing lid locks in position.

• Tip Pan:

  This is a common pre-staging machine integrated into the baler. This part aids in the loading process by being a staging hopper where the materials are initially loaded. When the baling machine is ready for the next loading cycle, hydraulic arms tip the pan so that the initially loaded materials fall into the chamber.

• Ejection Rams or Arms:

  After compression, ejection rams remove the baled material from the chamber. Fully ejecting the bale and other materials that did not form together helps minimize contamination.

  

  
  

• Automatic Tying Mechanism:

  This is one of the integral parts of an automatic baler machine. When the bale is completely compacted, mechanical systems wrap tie wires around the bale. This is done either before ejection or while the bale is being ejected. This assembly is usually seen in horizontal balers. It consists of tie wire cutters, twisters, knotters, and tensioners.

• Bale Ties:

  These are wires or straps that wrap around the bales to prevent them from becoming loose after compaction. Bale ties must have sufficient strength to counter the rebound or expansion of the materials. There are different types of bale ties according to material, finish, and loop. Below are the most common types.

  

  
  

  • Galvanized Wire:

    This is a type of wire finish in which the wire is coated or dipped in a bath of molten zinc. Wires are galvanized to increase their corrosion resistance. Galvanized wires are silver or gray with little oil residue.

  • Black Annealed Wire:

    This is a type of finish where the wire undergoes an annealing process. The wire is heated and cooled for a specific rate making the wire more flexible and ductile. Black annealed wires are easier to use because of the added ductility. A layer of thin oil is coated to lubricate it against the baling machine. The oil also protects the wire from corrosion.

Chapter 5: Applications of Balers

Balers are mostly used in scrap material recycling. Below are the most common uses of balers and the suggested types for each application.

• Steel Recycling:

  Balers are used for compacting steel cans, aluminum cans, steel sheets, radiator caps, copper wires, and clips. For lighter metals such as cans and sheets, a two-ram baler is enough. But for compacting heavier, thicker metals, ferrous balers consisting of three hydraulic cylinders are more suitable.

  

  
  

• Corrugated Cardboard and Paper Recycling:

  Balers are used for materials such as cardboard, office papers, magazines, newspapers, and so forth. An average office worker produces about 2 pounds of paper products per day. Mixed paper makes up an estimated 70% of office total waste. Large recycling plants use horizontal, single ram balers with automatic tying mechanisms. For small to medium scale storage and recycling, standard mill size balers and stand-alone vertical baling machines are sufficient.

  

  
  

• Plastic Recycling:

  This includes PET and HDPE bottles, plastic films, rigid PP containers, rigid and flexible PVC materials, electronic and automotive plastic scraps, and so on. Before feeding to the recycling facility, proper sorting must be done according to type, origin, and characteristics. For baling multiple types of plastics, it is important to prevent contamination between cycles to comply with the recycling facility standards.

  

  
  

• Foam Recycling:

  Foams are light materials with low densities, taking up much space when stored. Some foams, such as most polyurethane foams, are thermosetting plastics. This means their properties change upon curing which cannot be reversed. This makes it difficult to recycle such foams and the only way to manage these wastes is through incineration or landfill storage. Balers help minimize space consumed by compressing weights of more than a thousand pounds into a volume of about 45 cubic feet.

• Textile Recycling:

  This includes used clothing, carpets, rugs, wool, and other fibrous materials. Baling textiles is different from baling other materials such as steel and plastic since it uses less force but requires the process to be clean and stain free. The main objective of baling textiles is to reduce the space consumed for hauling and transportation efficiency. Most balers used for textiles are vertical balers.

  

  
  

• Agriculture

  As mentioned in the earlier chapters, balers are used in compacting animal fodder to help control moisture and retain nutrients. Balers originally emerged as a solution for bundling and storing haystacks. The concept is then applied to scrap material handling. Round balers are the most common for animal forage baling.

Conclusion:

• Balers are used to compress materials such as agricultural goods and recyclable materials to achieve better material handling and storage.
• The first balers were developed for agricultural applications. Tractor balers eliminated manual raking, bundling, and wrapping of haystacks. The concept of baling is then applied to industrial and domestic wastes to save storage and transportation costs.
• There are different types of balers classified according to ram orientation and the number of strokes or cylinders. Balers can be classified into vertical and horizontal balers. Vertical balers are simpler and smaller than horizontal balers. Horizontal balers, on the other hand, are used for large scale material processing applications.
• Single-ram balers can be further classified into open-end and close-end balers. Open-end functions like an extruding machine where the scrap materials are compressed against the previous bale. Closed-end balers have a closed-door on the other end where the materials are pressed.
• Two-ram balers compress the bale from two directions. These are usually configured forming an L shape. Since the width of the opening is not limited to the dimension of the bale, two-ram balers have a faster feed rate.
• Ferrous balers are machines with two or more cylinders. Its main difference is the pressing lid that pre-presses the materials before forming it into a bale.