Santos et al. Wall friction angle (against SS plate) = ϕ’ = 25º Bulk density = γ = 22 lb/cu ft Angle of internal friction. Basic silo shapes: a conical; b wedge-shaped; c asymmetric wedge-shaped; d. UK-based powder flow solutions firm Freeman Technology offers this video on how particulate materials react when aerated, loosely packed or. mechanical interlocking of large particles forming an arch 2. 2. Antimicrobial AlphaSan RC 5000 / RC 2000 Powder Flow Characteristics Flow Rate Indices Flow Rate Index (FRI) 115. Air pads may be needed to move the first material and merely gravity or small vibrations can be sufficient for the second. When bulk solids build up into an arch or dome-like shape over the hopper’s outlet and block the flow, it’s called arching or bridging. bulk solid materials exhibit in bins and silos. 1. High Shear Mixers and. a hole made or used by rats 2. Typically, they are used when flow by gravity alone will not work or when it is impractical to provide the design that is required for reliable flow. Figure 1: Manufacturing pharmaceutical tablets and capsules involves several powder handling steps. Traditional powder testing methods cannot force the bridging to occur in a repeatable manner and thus they cannot discriminate flow differences between powders. In this study, we showed that the major principal stress (σ1) at the bin outlet is required for. Prevent bridging and ratholing. The final potential issue is erratic flow, in which flow alternates between ratholing and arching (see Figure 1). In a bin, the powder is submitted to pressure, due to the fact that there is a height of powder in the bin, the powder on top pushing on the powder below the hopper. Reaching a certain level in the bin where the material has time to consolidate. The hopper design plays a role in this as hoppers with sharp angles and rough surfaces can inhibit powder flow. LIW feeder flow rates can be compromised when the sudden change of the powder weight (e. Ratholing. flow, including ratholing, erratic flow, flood-ing and segregation. Changing (reformulating) the powder to reduce the cohesive strength and wall fric- tion, however, may reduce the likelihood of ratholing. 456 inches. Retrofit solutions. It is only possible to compare materials using the same reference stress. Two modes of flow can result in dense phase, namely piston/plug flow and. Explains how bulk solids flow influences the design of a plant or an installation. 10). We Resolve Storage Structure Ratholing. Even high viscous material can be fed through the feeder and discharger smoothly. Boateng AA, Barr PV. Jenike shear testing has determined the following. Arching. Depending on their makeup, products in powder or bulk form are prone to cling to surfaces, especially if they’re high in fat or moisture. . was used to control the flow of powder. Solve your powder handling problems, whether it is. Understanding the rheological properties of the. described ratholing and powder bridging in a small-scale feeder for fine, cohesive and compressible powders (Santos et al. The API AeroFlow® automated flowability analyzer was tested using 6 pharmaceutical excipients. 2. However, when the fine iron is held inside a coagulation of powder, then it could be held out of the reach of the maximum magnetic force. This type of flow pattern is indicative of uniform, first-in-first-out flow, where ratholing, erratic flow, segregation, and flooding problems are mitigated. Powder blockage in silos. Able to work with a variety of material with flow adjusting mechanism. 3. Powder strength data at each consolidating stress are plotted on the graph in Figure 4 to produce a graph called a “flow function. Measuring flow properties leads to proper equipment selection and process reliability. Jenike & Johanson is presenting the following AIChE sponsored courses June 18-20 at the Canadian Management Centre in Toronto:Flow of Solids in Bins, Powder Bulk Solids is part of the Informa Markets Division of Informa PLCRat-holing problem: * is one of common powder flow problems * When powders are released via a butterfly or slide valve, flow takes place directly above the container outlet. A high fat powder (HFP) with 73% milk fat content, whey permeate powder (WPP) with 86% lactose, rennet casein powder (RCP) and sodium caseinate powder (SCP) were donated by Kerry Ltd. Silo discharge solutions for powder bridging and ratholing. This was attributed to the fact that the poor flowability of APAP could cause ratholing and high flow variations, especially when the powder. rathole, bridging and segregation to occur. 23Marinelli will discuss how to design the best kind of bin, silo, hopper, or feeder at Powder & Bulk Solids Texas, October 13-14, as one of two conference sessions he will present. See Fig. Poor flowability of powders in a hopper means that flow obstruction due to arching occurs or uneven flow causes ratholing. Despite being a simple test of compressibility, it can be useful for identification of powder flow behavior. Expanded flow: Term used to describe flow in a vessel that combines a core flow converging hopper with a mass flow attached below it. Hoppers designed for mass flow with high-quality surface finishes can address these issues. How it works. Besides that, powder flow can be determine by the angle of repose make by the powder itself when poured onto a flat surface throughout the hopper. In addition to potential ratholing, powders, like cement or flour, can become aerated when filling a bin and, if the silo is not designed with sufficient retention time for the material to become deaerated by the time it reaches the outlet, it will flow out of the silo uncontrollably, like. It is the only flow aid that can handle. Minor powder flow issues during R&D can turn into major headaches once scale-up to industrial production begins. Critical Rathole Diameters, Df, ft—“D” is the diameter of the opening required to collapse a rathole, while “f” stands for funnel flow. Preventing Flow Stoppages in Powder Handling Processes. Bridging, ratholing, arching and comparable behaviors are the bane of powder handling and formulating. Data were presented as mean. bulk solid materials exhibit in bins and silos. , answered a few questions from Powder & Bulk Solidson common powder handling and flow issues and how operators can take steps to fix or prevent. 5). Ratholing. Powder avalanching in a rotating drum evaluates dynamic powder flow characteristics based on theAn annular shear cell was used for measuring the flow function and effective angle of internal friction, as described by Teunou, Fitzpatrick, and Synnott (1999a). Table 1 – Flow Property Parameters Measured on Three Powders with the Jenike and Peschl Testers . The advantages for handling powders and bulk solids via fluidization instead of traditional deaerated gravity flow include: Elimination or reduction of arching (bridging) or ratholing problems Powder Cone Valve System. If the material being handled is cohesive, the material outside of this channel will. 4. The vane lid is used to perform the flow function test. A bin experiencing ratholing will have limited live (i. Mechanical Agitation when used properly will condition the material to a uniform bulk. Under the silo a screw feeder with a varying pitch. Gravity Flow. Arching/Bridging & Ratholing. Attempts to initiate flow, such as use of vibration on hopper with rubber mallet or increasing powder paddle feeder, did not work. 2002). • The particle size distribution – indicator of powder flow and the segregation potential • Bulk and tapped density – indicator of powder flow, mixing (fill volume) and tablet die filling. It allows users to measure the dynamic flow and shear properties of powders as well as quantifying bulk properties such as density, compressibility and permeability. Eastern/11 a. Getting the powder flow wrong can be highly disruptive to plant performance and productivity, particularly where equipment has to be taken off-line and stripped down for cleaning out blockages. It may be necessary to apply several linear vibrators when the entire bin must be cleaned. "Rotoflo is the best silo discharger!Ratholing can occur when coal flow takes place in a channel located above the silo, bunker or hopper outlet. flowability. UNIT- 3: HANDLING OF SOLIDS (2 HOURS) Sliding and flow of powder, Method for free flowing powder and granules, methods for cohesive powders Bins, Vacuum and conveyor. A key variable that will have an impact on the flow is its cohesive strength. A brief introduction to discrete elemental method (DEM) which computes and models powder. Powder Hand Process 4:293–299. 11. the types of flow problems that can occur and the flow patterns. ratholing (when the powder flows out only from the center leaving the rest of the material static against the walls). It offers automatic and controlled discharge of virtually any powder type, winning where other systems have failed. Powder & Bulk Processing. High batch accuracy with difficult-to- handle material. 361. The unique design can feed sticky, fluffy, lumpy, flaky, and fibrous materials without issues of bridging and ratholing in the hopper. The purposes of this investigation were to develop a method to evaluate flow properties of powders from avalanching tests and to detect similarities and relationships between these data and conventional powder flow properties. Unload and produce good faster in your production process. As the level of fly ash in the flow channel drops, a resistance to further flow into this channel occurs due to. Andrew W. ) (Ganesh et al. 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. 1. ), and dry, uniformly-sized larger materials will be free flowing. 71 Funnel / core flow. 9b, although the variation of the blend flow was larger compared to the total powder flow in case study 1. 36 3 Wall Friction Angle 24. . Unstick material and promote even flow. Hey Guys! Today I'm going to show you how to replace a bad cv joint (Constant Velocity Joint) step by step. Check drier is switched on. Material Flow Solutions, Inc. 9 b, although the variation of the blend flow was larger compared to the total powder flow in case study 1. Effective feeder design not only enhances the flow within bins, hoppers, and stockpiles but also. hopper that gives mass flow with one powder may give core flow with another. ”. Angle of repose. Powder Rheology. 2. Material hang-up (arching and/or ratholing) problems are generally caused by one of four things: cohesive forces between powder particles or granules, external forces, inter-particle locking, or elastic constraint issues. Bridging, ratholing, arching and comparable behaviors are the bane of powder handling and formulating. Fluidization is commonly used with pulverized fuel handling, drying operations, reaction processes, and fine powder hopper discharge systems. to 20 deg. In silos and hoppers it’s often the cause of flow problems like ratholing and bridging. 2. Geometry modifications are. 9b, although the variation of the blend flow was larger compared to the total powder flow in case study 1. The large open inlet exceeds most materials’ critical arching diameter, preventing bridging and ratholing. 1 Shear strength. This is indicated in hopper calculations as “Free Flow” or “0. The principles discussed in this chapter can be applied to analyzing new or existing equipment designs. the relationship is called powder flow function Yield locus and family of yield loci Determination of y and c. An arching flow p Figure 3. 4. As a general rule, extremely fine powders (<200 mesh) deaerate and pack readily (dusts, talc, etc. refilling) and unexpected events (e. This occurs when particles are conveyed in the gas stream at a velocity that is less than the saltation velocity. Ratholing occurs when material in the center discharges completely while material nearer the walls of the hopper. 361 14. Conducting studies throughout R&D and scale-up can help identify and isolate where in the process a formulation issue began. Consequently, meas-urement of the wall friction characteristic of a. m. T or F A bulk solid is a granular solid, such as gravel, sand, sugar, grain, cement, or other solid material, that can be made to flow. Wall friction, internal friction and bridging properties determine the applicable hopper angle and opening diameter. For calculation of bridges and ratholing in silos, there are two main phenomena to be. How to prevent solids and powder flow stoppages with proper feeder design FREE | October 18,. Our pneumatic and electric bin and hopper vibrators will: Promote the consistent and controlled material flow of dry or semi-dry bulk materials. 4. Use the following guidelines for impacting vibrators: Wall Thickness of 0. 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. Particle size also affects wetting. Powder is moist. This method may be used for all powders, dairy and non-dairy products. flow rate through an orifice compressibility index and hausner ratio angle of repose shear cell. At this point, peripheral bulk materials remain in place, so the hopper cannot be emptied. Flow and potential rathole formation in conical hoppers. This results in a no-flow. Hoppers designed for mass flow with high-quality surface finishes can address these issues. When the flow channel empties and material flow ceases, it can form a stable rathole that may collapse and block the opening. Ratholing occurs when discharge takes place only in a flow channel located above the outlet. 448 m, respectively), corroborating the previous results that demonstrated that shape had more. 2 Calculation of the Minimum Required Outlet. Flow function test. 3’ diameter opening is required to collapse a rathole, even at this low head. Its unique construction fulfills allows for quantitative dosing steadily and evenly. Free-Flow: The powder flows reliably through very small outlet dimensions under gravity. 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. The Cone Valve technology within each of the Matcon IBCs overcomes powder bridging due to both the lifting action of the cone and its integral vibration during lift. Additionally, when vibrators are used, the Magnetic. Bridging or ratholing in the silo can block the whole process and cause a discontinuity with high technical and financial consequences. • Stable and strong thanks to high-quality Inox tube frame construction. 487 and 1. 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. Frequently powders that are deemed easy flowing exhibit flow problems such as bridging, ratholing, or erratic discharge. , flow pattern (mass flow or funnel flow), and obstructions to flow (arching, ratholing). 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. Still, the material at the bin walls remains stagnant and leaves. Conversely, StarTab hadPoor material flow doesn’t just affect productivity. Chem Eng Sci. Mixing & Blending. Before. This can lead to ratholing and bridges. Circle Feeder is the premier choice feeder that can prevent the segregation during mass flow discharging. 2. Powder blockage in silos. A proven and practical scientific approach for designing bins and feeders based on a material’s flow properties. Pacific, Joe Marinelli, president, Solids Handling Technologies Inc. Discharge of powder from a hopper or bin is a common operation in solid dosage form manufacture. A superb discharge device, it overcomes all the typical powder handling and flow problems of bridging, blockages, mix segregation, flushing and core flow that are commonly associated with butterfly valves. Bulk solids problems such as bridging, ratholing and demixing are proactively prevented. Ratholing can lead to costly powder flow problems. Robert Sedlock. 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. 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. Aside from funnel flow, powder bridging is another undesirable flow issue which can occur in the hopper (Fig. 2. In all applications, this fluidizer prevents bridging, ratholing, and material hang-ups. Identifies suitable test methods and helps to interpret and understand their results. If the material is even slightly cohesive, material may stick to the walls and eventually become part of the bin structure. Powder flow is a critical attribute of pharmaceutical blends to ensure tablet weight uniformity and production of tablets with consistent and reproducible properties. Powder Machine Parameter Value/Equation 1 Jenike 1 Inst Flow Function 0. If you are experiencing issues with dust in your manufacturing facility, it is probably due to open processing. The purposes of this investigation were to develop a method to evaluate flow properties of powders from avalanching tests and to detect similarities and relationships between. 3 and Fig. Powder Mix Segregation. For example, a Flodex may show a neat API powder has flowability of 26mm, with a round tablet design of 12mm in diameter. Jenike, who pioneered the theory of bulk solids flow at the University of Utah in Salt. Systems supplied by PTSA often include silos, hoppers, and other storage vessels. Keywords: live bottom, cohesive, powder, hopper design. 10). While these vessels are simple in design, the choice of instruments and devices fitted will often make the difference to whether the material floes or not. 14. Carson, “Fine Powder Flow Phenomena plastic powder, food products, and pharmaceuticals. Process Systems 1. Most flow problems are connected with the funnel flow pattern and can be avoided if the hopper is designed for mass flow (Johanson, 2002, Purutyan et al. TheFlowability is the ability of a powder to flow, and it is measured as the time in seconds necessary for a given volume of powder to leave a rotary drum through a slit of a certain size. 3b) occurs in case of funnel flow if only the bulk solid above the outlet is flowing out, and the remaining bulk solid - the stagnant zones – is consolidated and forms the rathole. Arches come in two types: interlocking arches, built up of large, mechanically. Jenike shear testing has determined the following characteristics given below. Figure 1. flow, including ratholing, erratic flow, flood-ing and segregation. Reduce costs in manual labor for unsticking materials from bins or hopper walls. 4. LEARN MORE Powder Cone Valve System. Options for explosion proof and pneumatic vibrators for hazardous. Bridges of powder can form in your containers preventing flow. Figure 2: The two primary flow patterns that occur in gravity discharge are funnel flow and mass flow. A mass flow screw feeder prevents preferential flow which can lead to ratholing and arching problems. Valves & Actuators. 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. 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. Flow issues can hurt your facility so let us fix your ratholing problems. 2. • Easy to clean due to detachable components. One of the recommended types of flow aids is called Mechanical Agitation. In systems not designed with the material type in mind, powders and bulk solids can. Dimensions to Prevent Arching: Mass Flow Bin. One of the recommended types of flow aids is called Mechanical Agitation. Air displacement as the product flows from the container can cause segregation, leading to an inconsistent end product. 327. E & FN Spon, London and New York, pp 131–141Bin Activators are equipment conically shaped that aid dry bulk material flow from storage silos, or hoppers. Flow aids are used to return to a more regulated flow pattern and are relatively inexpensive. Problems of powder flow a. The way bulk powders flow impacts on the design of. Occurs for small outlet size =< 6-10 * max particle size (D 90 ) b. encountered issues with achieving a consistent feed rate of a highly drug-loaded pre-blend due to the poor flowability and packing consistency. 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. 770-255-1322. There are many factors, e. Powder has a natural ability to move and fall when it is stored in a silo or a hopper. Problems such as arching, bridging, segregation, ratholing, and more, resulting from a material with poor flow properties, can cause issues such as:. The large open inlet exceeds most materials’ critical arching diameter, preventing bridging and ratholing. 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. 19 5 Inst Flow Function - Prorated 0. Avoid silo problems, such as bridging, funnel flow, ratholing, arching, segregation and product decay. Provided here is a review of shear-cell testing and how the technique can be used to predict arching, ratholing and other behaviors. AirSweep breaks up material blocks and sweeps the vessel walls clean. Apparatus. On the other hand, NP0 produced mass flow behaviour even for the narrowest orifice diameter of 2 mm. (USP 1-May-2024) Changes in flow rate as the container empties can also be. Irregular flow; d. 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. 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. Discharge of powder from a hopper or bin is a common operation in solid dosage form manufacture. This creates a non-flow regime whereby a discharge aid is needed to re-initiate powder flow from the silo. 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. The entire process is user-controlled and transparent: Diagrams and extrapolations. The reason for this is the strength (unconfined yield strength) of the bulk solid. FLOW PROBLEMS 2. Shear cell techniques were used to measur e the following powder flow pro-perties: powder flowfuncti on, effective angle of internal fricti on and angle of wall friction. The depth of the trough into which the powder is filled is 12 mm and. Increase powder fluidity enables spreading. In this work, the piping flow of cohesive granular materials in a flat-bottomed silo is investigated using finite element method (FEM). Aside from funnel flow, powder bridging is another undesirable flow issue which can occur in the hopper (Fig. If you’re in supplement processing and need expert advice or equipment related to powder handling, supplement or food production, call Right Stuff Equipment at 303. Typical powder flow issues found in the hopper are ratholing, bridging, and segregation. . May be formed by 1. offers powder testing services (flowability, friction, time consolidation, strength as used for comparative tests, silo design for flow and silo design for strength) and. The hopper design can play a role in this as those with sharp angles and rough surfaces can inhibit powder flow. While addition of magnesium stearate had improved powder flow, ratholing was still observed for T100M across all orifice diameters. Granular materials can exhibit complex solid- and liquid-like behaviours which are not fully understood. Mass flow develops when all the material in a silo is in motion whenever any is withdrawn. Motors & Drives Valves & Actuators Powder & Bulk Solids. 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. This device mixes with the bulk powder to increase. Ratholing. Powder rheology is the study of the behaviour of powders as bulk assemblies, consisting of solids, liquids and gases. Provided here is a review of shear-cell testing and how the technique can be used to predict arching, ratholing and other behaviors. Native corn starch did not flow from the hopper, so tablets were not compressed and had a severe ratholing problem. 3485 Empresa Drive San Luis Obispo, CA 93401 Tel: 805-541-0901. This article describes a study scientists conducted to resolve a powder-binding problem that developed during the scale-up—from proof-of-concept scale to pilot. 1 is handled? Is the 100-mm diameter outlet of the hopper large enough to prevent an obstruction to flow?Powder flow tester, Software for silo design. Eliminate bridging, rat holes, stuck material and uneven flow in chutes and pipes. Whether powder will flow smoothly or in an erratic manner inside a bin or a hopper depends on the flow pattern inside that equipment. Particle size distribution (PSD) estimation by sieving of the two powders was performed according to Ph. Typically, a dilute phase line conveys less than 15 lb (~7 kg) of solids per pound (~0. These flow problems can result in powder caking, production delays, increased operator intervention, or product losses. A brief introduction to the flow properties of bulk solids, and common instruments and tests used to measure them, is given first, followed by a detailed summary of the research works. b. ), and dry, uniformly-sized larger materials will be free flowing. 8 B), F > 63 and F > 90 had practically equal outlet diameters (1. Flow difficulties at the blending step often manifest as slow/no discharge or ratholing. Here, flowability and magnetization were measured for a dual-phase steel powder in size fractions from 20 ⩽ D / μ m ⩽ 40 to > 200 µm. 2. Knowledge about bulk density of materials is essential for avoiding ratholing and arching effects in silos and hoppers. In order to achieve mass flow, tion hoppers) are shown in Figures 5 and 6, respectively. A critical orifice measurement apparatus was developed to study powder flow initiation from an arching state into an enclosure where the air pressure is reduced. 10a or M-cell that is. 2. 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. The ladder bowl allows the powder to flow evenly around this insertion station and keep a better powder level at the first tamping station. Material builds up on the vessel walls, restricting the flow and the vessel’s full storage capacity. The powder has relatively low cohesive strength. Referring now to another embodiment shown in FIGS. The reason for this is that when a result in a flooding condition at the outlet. 1. powder flow problems. Because of this flow pattern, funnel flow silos that are not emptied. Due to the cohesive strength of fine dry fly ash, the material is a great source of friction. Obstruction to flow due to bridging arises when a stable arch forms over the hopper outlet, which prevents material from being discharged . aid, modifying the feeder, or using gas injection. The corresponding control schemes at different levels for the feeding-blending system are provided in Table 6. , useable) capacity, as low as only 10–20% of the bin’s rated storage capacity. One of the recommended types of flow aids is called Mechanical Agitation. Funnel flow produces 'last in, first out' powder delivery and a greater likelihood of operational problems such as ratholing, segregation, and flooding. 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. The material forms a narrow passageway above the feed auger or outlet, while the remaining materials in the storage structure are stationary and can begin caking to. The flow properties that govern whether a powder is prone to ratholing include cohesive strength, wall fric-tion, and bulk density [1-5]. 4. (USP 1-May-2024) Of particular significance is the utility of monitoring flow continuously, since pulsating flow patterns have been observed even for free-flowing powders. 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. Motor with gear suitable for running at 30 rpm. Material flow from a bin or silo is inextricably linked to how the feeder extracts the material from the bin outlet. The hopper must be designed so the outlet diameter is larger than the outlet rathole critical diameter. spoilage, flooding, or ratholing are likely to occur, then a mass-flow discharge pattern should be selected. Pumps, Motors & Drives. offers powder testing services (flowability, friction, time consolidation, strength as used for comparative tests, silo design for flow and silo design for strength) and solves practical problems in the field of bulk solids handling (silo design for flow to avoid problems like arching, segregation, ratholing) on the basis of the mechanical properties. powder addition easier. Thus, reliable information of flow properties of the pulverized coal concerned is required for reliable flow from the hopper, which is essentially crucial in handling and processing operations [8], [9]. 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. The API AeroFlow automated flowability analyzer was tested using 6 pharma. ) but it. Again, this impacts powder bowl depth, evenness and weight control. 2. In this study, we showed that the.