Ratholing occurs when material in the center discharges completely while material nearer the walls of the hopper remains in place. Finally. In this study, we showed that the major principal stress (σ1) at the bin outlet is required for. There are two main reasons why no-flow conditions happen: arching and ratholing. Powder flow can be defined as the ease with which a powder will flow under a specified set of conditions. ‘Rat-holing’ (shown in Figure 2a) is the principle flow obstruction in a core-flow vessel where the powder in the flow-channel above the outlet discharges and leaves a stable. k. 2. 1. Bulk solids and powders frequently encounter various flow challenges, including bridging, ratholing, flooding, and inadequate flow rates, and more. May be formed by 1. ), and dry, uniformly-sized larger materials will be free flowing. Acceptable flow is required in powder transfer operations such as the emptying of tumble bins and conveyance of powders by gravity or screw feeders. Do you suffer from Bin Rash? When Material gets clogged in Bin, Hoppers and Silos, do you bang your hoppers with hammers? It is not a great solution and it c. Generally, flow is limited to a central flow pattern. This results in a no-flow. Table 1 – Flow Property Parameters Measured on Three Powders with the Jenike and Peschl Testers . Despite being a simple test of compressibility, it can be useful for identification of powder flow behavior. The reason for this is that when a result in a flooding condition at the outlet. If the material being handled is cohesive,. reviewing these solutions, however, it’s important to understand. Lower the total height requirement. Generally, flow is limited to a central flow pattern. m. Schematic representations of challenges arising on the storage (ratholing during silo storage - a), handling (build up on powder conveying line - b) and applications of high-protein dairy powders requiring rehydration (powder clumping. , 2003). . Powder strength is measured as “yield stress” by shearing particles trapped in the lid pockets against particles in the shear cell. 2 Flowability indicators used in industries 7 1. Rat holing is where a central void develops above the discharge outlet in place of the active flow channel. Even high viscous material can be fed through the. m. Our engineers can solve two common types of flow issues. Figure 10. The aeration of the disk fluidizer utilizes directional air flow along the wall of the chamber to loosen product and move it to the discharge point. As the silo empties, side material flows into the middle channel. 57. 0”. This chapter provides guidance in designing bulk solid (“powder”) handling equipment to provide consistent, reliable flow and to minimize segregation. Provided here is a review of shear-cell testing and how the technique can be used to predict arching, ratholing and other behaviors. ), and dry, uniformly-sized larger materials will be free flowing. Keep product moving by preventing buildup, bridging and ratholing. 3. The system is designed to help prevent powder bridging and ratholing in silos and hoppers. 3. Ratholing is influenced by the bin/hopper geometry and outlet size the material is fed through. Depending on the flow properties, these materials are difficult to handle. Typical powder flow issues found in the hopper are ratholing, bridging and segregation. Conversely, StarTab hadPowders. This is due to issues related to the flow pattern of most bulk solids: arching in the hopper occurs during mass flow when the arch builds sufficient strength to support the powder above it; ratholing in the storage vessel. It is critical to understand the type of hang-up that you may be experiencing. 3’ diameter opening is required to collapse a rathole, even at this low head. Arching, ratholing, caking, segregation and flooding are some of the commonly encountered flow problems in the handling of fine powders. Conversely, StarTab hadPoor material flow doesn’t just affect productivity. a more practical non-invasive method to visualize dynamic powder flow is needed that can help to quantify the efficacy of a given unit operation (such as in silos/bins) used in. Powder blockage in silos. These behaviours are related to the cohesive strength of the powder, which is a function of the applied consolidation pressure. Powder flow obstruction during hopper/bin discharge, such as arching or ratholing, remains an outstanding risk and cannot be reliably diagnosed using the existing flow function coefficient-based method. To overcome bridging the wall friction must be reduced or prevented from occurring. Rotoflo is designed to help with material handling ensuring that silo discharge is free-flowing and controlled when handling a number of diverse materials. Again, this impacts powder bowl depth, evenness and weight control. Typical powder flow issues found in the hopper are ratholing, bridging and segregation. Numerous cement plants are plagued with bulk solids flow problems like bridging, ratholing, and flooding, each of which can negatively impact production efficiency. Ratholing: can occur in a bin when the powder empties through a central flow channel, but the material at the bin walls remains stagnant and leaves an empty hole (rathole) through the material, starting at the bin outlet (Fig. Air displacement as the product flows from the container can cause segregation, leading to an inconsistent end product. Ratholing is influenced by the bin/hopper geometry and outlet size the material is fed through. Funnel flow produces 'last in, first out' powder delivery and a greater likelihood of operational problems such as ratholing, segregation, and flooding. The cell has a fixed shearing rate of 7 mm min −1 and external and internal diameters of 164 and 120 mm, respectively. bulk solid materials exhibit in bins and silos. size, form, elasticity, water content and temperature, which influence compressibility. What Can Cause A. As occurrences of bulk powder flow issues are strongly affected by the flow pattern during discharge. The hopper to be designed is conical. Powder rheology is the study of the behaviour of powders as bulk assemblies, consisting of solids, liquids and gases. Hopper Design Principles. Wall friction, internal friction and bridging properties determine the applicable hopper angle and opening diameter. W. TheWolfenbuttel, Germany) is used for measuring the flow properties of bulk solids or powder ( fig. , 2018). The API AeroFlow automated flowability analyzer was tested using 6 pharma. Test results allow a formulator to determine required hopper outlet dimensions that will prevent flow stoppages, hopper angles necessary to prevent ratholing, and outlet sizes required to achieve. Powder flow obstruction during hopper/bin discharge, such as arching or ratholing, remains an outstanding risk and cannot be reliably diagnosed using the existing flow function coefficient-based method. 3º Peschl 4 Inst Flow Function - Raw 0. Flow obstructions occur when the forces opposing motion exceed the forces promoting. It is critical to understand the type of hang-up that you may be experiencing. Different process problems, such as arching, ratholing, and segregation could arise during silo operation due to its poor design or extreme operating conditions. The reason for this is the strength (unconfined yield strength) of the bulk solid. Air pads may be needed to move the first material and merely gravity or small vibrations can be sufficient for the second. Increased availability has accelerated the use of single-use systems in the biopharmaceutical industry. 2. The frequency of the vibration needs careful consideration as it could affect the flow ability of the powder. • Prevent ratholing, bridging and damage to the material. Systems supplied by PTSA often include silos, hoppers, and other storage vessels. High batch accuracy with difficult-to- handle material. 4. These issues are most likely due to improper storage, a poorly selected. 26. 2 Mass flow bins sufficient cohesive strength that its critical rathole diameter (the flow channel diameter at Flooding and ratholing problems can be which a rathole becomes. Some products like dry cell battery. Traditional powder testing methods cannot force the bridging to occur in a repeatable manner and thus they cannot discriminate flow differences between powders. If a mass-flow bin is required based on the flow char-acteristics of the powder or bulk solids, the next step is to determine an appropriate outlet size and feeder. If a mass-flow bin is required based on the flow char-acteristics of the powder or bulk solids, the next step is to determine an appropriate outlet size and feeder. powder addition easier. Joe will describe uses for liners such as TIVAR 88 and 2B stainless steel along with coatings such as electrostatic powder coatings and Plasite 7122 epoxy coating. Why are my powders are not flowing efficiently?Ratholing occurs when discharge takes place only in a flow channel located above the outlet. They are most often used in storage bins and chutes to promote flow of stored material, but they can also be used in continuous flow process vessels and. Our pneumatic and electric chute and pipe vibrators and vibratory equipment will: Unload dry or semi dry bulk material. Bulk Material. An extreme case of funnel flow is referred to as “ratholing”. com. This method may be used for all powders, dairy and non-dairy products. The Circle Feeder can be manufactured with several outlets for “one. 36 3 Wall Friction Angle 24. Holmes described two flow issues that commonly occur in bins, hoppers and silos: arching and ratholing. FLOW PROBLEMS 2. In the present work, the discharge characteristics of non-gravity-driven powder in the horizontal silo were investigated experimentally, with an emphasis on the half cone angle, aeration. (710, 500, 355, 250, 180, 125, 90 and 63 μm, sieves Retsch) using a sieve shaker (Retsch AS 200 digit, Germany) with a vibratory amplitude of 2 mm [40]. Poor flowability of powders in a hopper means that flow obstruction due to arching occurs or uneven flow causes ratholing. 2. include arching (when the powder forms a cohesive bridge over the outlet) and ratholing (when the powder flows out only from the. The material that is. Mass flow exhibits a first-in-first-out flow sequence, allowing the product at the bottom (coarser or heavier particles) to discharge first. • Minimal power consumption. m. 93+0. Discharge of powder from a hopper or bin is a common operation in solid dosage form manufacture. It is critical to measure a powder’s flow properties before designing a handling system or solving a flow problem. Arching, ratholing, caking, segregation and flooding are some of the commonly encountered flow problems in theAlso in the case of funnel flow, asymmetry is of no help when ratholing has to be avoided (Fig. , Listowel, Ireland. a cohesive arch when particles bond together ii. An arching flow p Figure 3. , and J. k. b. Avoid silo problems, such as bridging, funnel flow, ratholing, arching, segregation and product decay. Powder Rheology. Eliminate Bridging and Ratholing The Carman Vibrating Bin Discharger eliminates. In plug flow bins, the material flows in the centre of the bin, into which the sides slough as the material is drawn from the bin. Santos et al. hopper that gives mass flow with one powder may give core flow with another. One of the recommended types of flow aids is called Mechanical Agitation. Solve your powder handling problems, whether it is. Bioprocess Equipment for biotech and pharmaceutical industries. ”. ) (Ganesh et al. (For an illustration of arching and ratholing, see the online version of this article at If a stable rathole forms in a hopper,Powder flow is critical to a range of pharmaceutical manufacturing processes. The critical dimensions of ESP hoppers, such as the outlet opening and hopper half angle must be confirmed to. Sometimes, slow mixing paddles can keep bridging and ratholes under control. If the material being handled is cohesive, the material outside of this channel will. Two modes of flow can result in dense phase, namely piston/plug flow and. "Rotoflo is the best silo discharger! Mass flow develops when all the material in a silo is in motion whenever any is withdrawn. "ratholing" can occur, that is, the diameter at which. adhesive nature of a material could influence the feedability of materials over time through screw layering or bridging/ratholing, limiting the powder flow through. Lack of discharge in theFlow-rate limitation and flooding: problems specific to fine powders. 0 HOPPER DESIGN 5. spoilage, flooding, or ratholing are likely to occur, then a mass-flow discharge pattern should be selected. They all refer. Rat-holing causes a funnel flow effect, where the powder flows freely above the outlet but then stops as the compacted powder is held in the silo or hopper. Thousands of plants around the world use AirSweep flow aid systems to solve bridging, ratholing, and other material flow problems. The primary design objective when determining the bin geometry is to ensure that bulk solid or powder will flow with the effects of gravity, and without flow obstructions occurring. In practice, this group of bulk materials is the most common. . Researchers at Purdue University have developed a new technology that solves the caking, bridging, and ratholing that occurs in powder flow from hoppers and bins in agriculture and other industries. 3485 Empresa Drive San Luis Obispo, CA 93401 Tel: 805-541-0901. Explains how bulk solids flow influences the design of a plant or an installation. Ratholing, another flow arresting situation, is when material directly above the outlet flows but the rest of the powder mass closest to the walls does not, creating a tunnel. Such hoppers are sensitive to arching and ratholing. Valves & Actuators. Powder flow is critical to a range of pharmaceutical manufacturing processes. Section 1 Arching and Ratholing Dimensions of the Flow Report indicates the arching and ratholing dimensions of your material as a function of time at rest, temperature, etc, as follows: Arching Dimensions Time at Rest, hours -- In our example, the material was tested to simulate 0 hours storage (continuous flow) or as if the material was put. 14. The rest of powder compacts under vibration and get les flow-able in the time, so if a flow channel is established it will stay on the same place. Due to the pressure, some solids tend to be more cohesive , when powders become cohesive, they can form archs or rathole , 2 phenomena very detrimental to the flow of powder and. At the heart of our Powder Handling System is an IBC fitted with our patented Cone Valve Technology, a unique discharge valve that eliminates typical powder flow problems. Reduce costs in manual labor for unsticking material from chutes and pipes. The hopper design can play a role in this as those with sharp angles and rough surfaces can inhibit powder flow. The behavior is irregular and often catastrophic for achieving regular powder flow. steeper than. 31+0. 363 14. 1 Funnel flow bins When a fine powder is stored in and discharged from a bin having a funnel flow pattern, ratholing and flooding problems are almost inevitable. This method may be used for all powders, dairy and non-dairy products. Problems associated with ratholing are flooding, substantial variation of density in product, and eventually no-flow. It is the only flow aid that can handle. 2017). Forty years ago, Jenike [Gravity Flow of Bulk Solids, Bulletin 108, Utah Engineering Station, 1961] and Johanson [Flow Indices in the Prediction of Powder Behavior, Pharmaceutical Manufacturing. Bulk solids problems such as bridging, ratholing and demixing are proactively prevented. Thus, it will not be separated. Jenike, who pioneered the theory of bulk solids flow at the University of Utah in Salt. Expanded flow silos and stockpiles are recommended for storing large quantities of non-degrading materials and for modifying existing funnel-flow silos to correct problems caused by arching, ratholing and flushing. It may be necessary to apply several linear vibrators when the entire bin must be cleaned. It is mainly used clinically as an adaptogen, but antihypertensive effects have been reported for the. On the other hand, NP0 produced mass flow behaviour even for the narrowest orifice diameter of 2 mm. These flow problems can result in powder caking, production delays, increased operator intervention, or product losses. A brief introduction to discrete elemental method (DEM) which computes and models powder. Irregular flow; d. powder flow is uncontrolled due to randomly collapsing of rathole (Royal and Carson. The key to feeding cohesive materials in a screw feeder is with the use of Flow Aids. Pivotal work on the development of the theory of bulk solids flow began in earnest in the early 1950s, when. Unload and produce good faster in your production process. That’s why. The reason for this is that when a result in a flooding condition at the outlet. This can lead to problems like buildup on the interior of tubes or vessels, or “ratholing” or “bridging” of product in hoppers. These are examples of material flow problems. Discharge of powder from a hopper or bin is a common operation in solid dosage form manufacture. Equipment for powdered metals, ceramic powders, pigments, chemicals, super-abrasives. Ratholing occurs when cohesive bulk materials are stored and conveyed in vessels with a funnel flow discharge pattern. capacity — as low as only 10–20% of the bin’s rated stor- age capacity. Flow obstructions occur when the forces opposing motion exceed the forces promoting. Powder flow obstruction during hopper/bin discharge, such as arching or ratholing, remains an outstanding risk and cannot be reliably diagnosed using the existing flow function coefficient-based method. , 1998,. Minor powder flow issues during R&D can turn into major headaches once scale-up to industrial production begins. Mass flow develops when all the material in a silo is in motion whenever any is withdrawn. Visually detectable local ratholing and cratering in the fluid bed: Compressed air too moist, contains oil; relative humidity is too high inside the room in which the powder is processed. forms. Arching/Bridging & Ratholing. ) the powders are filled into closed cavities; this is followed by compaction using rigid punches and finally the product is ejected from the die. Material Flow Solutions, Inc. Eliminate bridging, rat holes, stuck material and uneven flow in chutes and pipes. 400 Business Park DriveRatholing is a scenario that powder starts. Rotoflo is designed to help with material handling ensuring that silo discharge is free-flowing and controlled when handling a number of diverse materials. Silo design for gravity flow; most economic. Mass flow eliminates ratholing and maximizes the pers with planar geometries (e. Cohesive Strength – The consolidation of powder may result in arching and ratholing within transfer equipment. Air pads may be needed to move the first material and merely gravity or small vibrations can be sufficient for the second. J. The hopper must be designed so the outlet diameter is larger than the outlet rathole critical diameter. The entire process is user-controlled and transparent: Diagrams and extrapolations. flow channel empties, flow stoppages will occur when powder along the walls remains stagnant. Flow difficulties at the blending step often manifest as slow/no discharge or ratholing. With. Silo blockage. The two most common flow problems experienced in a silo, bin or hopper are arching (bridging) and ratholing. Ratholing: can occur in a bin when the powder empties through a central flow channel, but the material at the bin walls remains stagnant and leaves an empty hole (rathole) through the material, starting at the bin outlet (Fig. Schulze RST which is equipped with either S-cell that is shown in fig. b. Ratholing occurs when material in the center discharges completely while material nearer the walls of the hopper. 4. Here, flowability and magnetization were measured for a dual-phase steel powder in size fractions from 20 ⩽ D / μ m ⩽ 40 to > 200 µm. Process Systems 1. Only with a not too poorly flowing bulk solid might it be possible that flow obstructions occur somewhat less often in asymmetric funnel flow silos compared to symmetric ones, because lessDetermine wall slopes for mass flow, by measuring the friction that develops between a bulk solid and any hopper wall material. Factors that affect the flow behavior are discussed. Powder flow obstruction during hopper/bin discharge, such as arching or ratholing, remains an outstanding risk and cannot be reliably diagnosed using the existing flow function coefficient-based method. Cleveland Vibrator Company offers a range of solutions for manufacturing and processing powder products from bin vibrators, feeders and conveyors to screeners for 10 micron and up. Bridging is the name given to the self- created arch that develops just above the outlet of a bulk material silo or hopper as it empties. When you have buildup in the silo, the loads associated with asymmetric flow can be detrimental to the structural integrity of the silo as they can lead to wall failure and total silo failure. mechanical interlocking of large particles forming an arch 2. Options for explosion proof and pneumatic vibrators for hazardous. Material builds up on the vessel walls, restricting the flow and the vessel’s full storage capacity. The primary measure of powder flowability is the powder flow function - which gives a measure of the amount of strength the material retains at a stress free surface following consolidation to a given stress level. In powder technology, the flow conditions are from. Acceptable flow is required in powder transfer operations such as the emptying of tumble bins and conveyance of powders by gravity or screw feeders. Polimak Bin Activators are used in several industrial applications to efficiently discharge dry solid materials in powder or granular form from upstream equipment, thereby, reducing bulk material bridging or ratholing while promoting mass. Its unique construction fulfills allows for quantitative dosing steadily and evenly. Segregation Ratholing (Fig. The final potential issue is erratic flow, in which flow alternates between ratholing and arching (see Figure 1). Valves & Actuators. In silos and hoppers it’s often the cause of flow problems like ratholing and bridging. The Wolfenbuttel, Germany) is used for measuring the flow properties of bulk solids or powder ( fig. 4. Allows study of full sized storage and gravity flow, along with vertical conveying up to 65 feet to the top of silo. Retrofit solutions. 4 Flow FactorsCohesive arching, jamming, particle segregation, and ratholing are all common occurrences during the production cycle. Mechanical Agitation when used properly will condition the material to a uniform bulk density and eliminate bridging/ratholing resulting in the material filling the flights of the feed. Note that this method does not work well if the bulk material is a powder that can compact easily. Measuring flow properties leads to proper equipment selection and process reliability. 20-36 , wherein there is shown a hopper assembly H which utilizes a hopper 401 and a hermetically sealed cover 402. LEARN MORE Powder Cone Valve System. 2. Material Flow Solutions, Inc. Where less desirable properties are present, poor powder flow can: lead to challenges during blending (no discharge or ratholing), 4 difficulties when discharging the powder into the hopper 5 or issues regarding weight uniformity in the tablet. Typically, a dilute phase line conveys less than 15 lb (~7 kg) of solids per pound (~0. If you are experiencing issues with dust in your manufacturing facility, it is probably due to open processing. Schulze RST which is equipped with either S-cell that is shown in fig. Caking of powder can have adverse effects on solubility, mixing, and dispersion resulting in loss of products, delays in launch and consumer complaints. 2. Apparatus. The nozzle releases highly pressurized air pulses to promote on-demand, first in and first out flow. Cohesive Arching Ratholing (Piping) B. Identifies suitable test methods and helps to interpret and understand their results. All figures are courtesy of the authors. 8 lb/min Feed Density Index (FDI) 24. 10a or M-cell that is. The hopper design can play a role in this as those with sharp angles and rough surfaces can inhibit powder flow. Material flow from a bin or silo is inextricably linked to how the feeder extracts the material from the bin outlet. The principles discussed in this chapter can be applied to analyzing new or existing equipment designs. Hoppers designed for mass flow with high-quality surface finishes can address these issues. The powder flow is measured using an X-ray-based mass flow meter (SETXvue XP-300, Enurga, Inc. , wedge-shaped and transi-usable capacity of the vessel. Flow issues can hurt your facility so let us fix your ratholing problems. Ratholing, another flow arresting situation, is when material directly above the outlet flows but the rest of the powder mass closest to the walls does not, creating a tunnel. Arching; b. Modeling of particle mixing and segregation in the transverse plane of a rotary kiln. The flow of powder out of a silo is stopping primarily for 2 reasons ; either formation of arches. Since funnel flow will result in a first-in, last-out flow sequence, any side-to-side segregation that occurred when the equipment was filled will often be exacerbated 7. g. Figure 10. Major Testing: Bulk Density Measurement [ USP<616>] Tapped Density. Arching. The typical problems encountered are either a cohesive arch or ratholing. 2. Powder Machine Parameter Value/Equation 1 Jenike 1 Inst Flow Function 0. Free-Flow: The powder flows reliably through very small outlet dimensions under gravity. To achieve this, a flow agent should adhere to the surface of particles of solids as shown in Figure 2. For system manufacturers, process engineers, and operators: The timely application of flow enhancing solutions is recommended to prevent quality issues and production interruptions, such as bridging, ratholing and demixing. The Circle Feeder can be manufactured with several outlets for “one. asymmetric conical. Bridges of powder can form in your containers preventing flow. At the heart of our valves is Matcon's world-famous Cone Valve Technology delivering efficient and flexible powder handling solutions, serving a range of. 71 Funnel / core flow. Powder flow is a critical attribute of pharmaceutical blends to ensure tablet weight uniformity and production of tablets with consistent and reproducible properties. Native corn starch did not flow from the hopper, so tablets were not compressed and had a severe ratholing problem. A mass flow screw feeder prevents preferential flow which can lead to ratholing and arching problems. 5). Flow rate evaluationThe model elucidated the impact of the material descriptors for density; powder flow; particle size; compressibility; permeability and wall friction angle on the feeding process. Mass-flow bin. 5). Rat-holing causes a funnel flow effect, where the powder flows freely above the outlet but then stops as the compacted powder is held in the silo or hopper. Mixing & Blending. :4167–4181. flow using an avalanching powder system and comparing it to the methods of determining Carr’s compressibility index and the critical orifice diameter approach. Ratholing is a scenario that powder starts . Ratholing: can occur in a bin when the powder empties through a central flow channel, but the material at the bin walls remains stagnant and leaves an empty hole (“rathole”) through the material, starting at the bin outlet (Figure 28. 1. The limiting condition for flow: c y ff - to reveal conditions under which the flow will occur. 5 kg) of gas at a pressure of less than 15 psig (~1 barg). Ratholing. The gyrators also reduce particle segregation to make sure each bag is completely. Efficiency– As explained earlier ratholing powder flow can be likened to creating a “funnel effect”,meaning silos and hoppers cannot be used to their full storage capacity. Magazine Events News & Notes Videos Podcasts Webinars White Papers Breakthrough Products Awards. The finest fraction did not flow through a Hall flowmeter, then. Ratholing is influenced by the bin/hopper geometry and outlet size the material is fed through. When hoppers are designed without consideration of the actual materials being handled, problems inevitably arise. 10). As the level of material in the flow channel drops, a resistance to further flow into. The. The reason for this is that when a powder becomes deaerated in the stagnant region of a funnel flow bin, it usually develops Ratholing: can occur in a bin when the powder empties through a central flow channel, but the material at the bin walls remains stagnant and leaves an empty hole (rathole) through the material, starting at the bin outlet (Fig. 1 Shear strength. They all have one thing in common: none will predict whether or not a powder will flow in a hopper. Obstruction to flow due to bridging arises when a stable arch forms over the hopper outlet, which prevents material from being discharged . Ratholing is a flow obstruction is a no-flow condition obstruction that can cause erratic that prevents material discharge discharge from a bin, as well as from a bin. The most common causes of these issues are: Improper storage; Poorly selected binder that is too cohesive with the API;. Flow stoppages due to arching and ratholing within ingredient feed hoppers and bins are more than just a nuisance, since these problems will directly contribute to the composition of the final blend for a period of time. The flow of powder in a hopper is linked to 3 properties : The powder internal friction : how easy the powder particle can move from each other. The total powder flow can be controlled in the level 1 closed-loop operation as indicated in Fig. Dimensions to Prevent Arching: Mass Flow Bin. The powder influences the silo by the flowability of powder causing bridging and ratholing. Typical powder flow issues found in the hopper are ratholing, bridging and segregation. Understanding the rheological properties of the. 24hr Emergency Service. (Note: The terms bulk solid, bulk material, and material are used interchangeably.