A major, new uranium plant in Namibia was experiencing constant mechanical failures on their recently installed agitators. Problems included shaft breakages, gearbox failure, and other associated problems.
After a visit to the site AFROMIX submitted a report, together with recommendations, to resolve the problems. Initial components were provided within three weeks, and complete rectifications within three months.
No reported mechanical failures have occurred since installation.
At the heart of every AFX peristaltic pump lies a heavy-duty peristaltic hose specially developed to work hand in hand with the pump roller technology installed in the AFX PUMP SERIES. We stock a comprehensive range of hose materials for each pump to be compatible with the unique chemical and abrasive characteristics of every application. A carefully designed and manufactured hose element is the single most vital component for the performance durability and efficiency of any peristaltic pump. To ensure a good pump you must have a good hose, and this is where AFX excels. Each hose we supply is built under stringent quality control measures, using high-quality, compounded rubbers, reinforced with four individual layers of braided nylon carefully set at optimum angles. Once cured, the outer diameter of each hose is precision machined to exacting tolerances ensuring a perfectly sized hose. An accurately sized hose ensures perfect compression, which eliminates internal slip (which reduces pump efficiency and allows for the abrasive slurries to prematurely destroy the hose).
NATURAL RUBBER (NR) |
EPDM |
| A general purpose material with excellent mechanical and abrasion resistant properties. Suitable for all water-based applications and mild acids, alkalis or oxidising agents. Max. fluid temperature: 80 °C Min. temperature: -20 °C | Ethylene propylene diene rubber. Excellent chemical resistance, especially to ketones, esters, alcohols and concentrated acids. Max. fluid temperature: 90 °C Min. temperature: -10 °C |
NITRILE (NBR) |
CSM (HYPALON®) |
| Acrylonitrile butadiene rubber. A durable material resistant to oils, greases, alkalis and detergents. Compliant to European BfR standards, this liner can also be used in a wide range of applications in the food industry. Max. fluid temperature: 80 °C Min. temperature: -10 °C | Chlorosuphonyl polyethylene rubber. Excellent chemical resistance to high concentration acids, ozones, and other oxidising materials. Max. fluid temperature: 80 °C Min. temperature: -10 °C |
CHEMICAL COMPATIBILITY CHART |
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Chemical Compatibility Chart - 2016 |
Download |
Peristaltic pumps are by nature inherently pulsing in operation. Excessive pressure spikes and pulsations within the pump system can be extremely damaging to the pump hose and the process system.
The primary reason for hose failure is from cyclic fatigue (number of hose compressions). Pump hose failure is inevitable, but exactly when hose failure will occur is dependent upon many factors and may not always be at a convenient time when a technician is watching the pump.
Our extensive range of peristaltic hose pumps includes one of the largest pumps of this type in the world. Our 150mm pump has a maximum flow rate of 147m³/hr and can deliver pressures up to 10 Bar. These units are ideal for thickener underflow applications.
OPERATING PRINCIPLE
APPLICATIONS |
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| Chemical: | Corrosive acids and shear sensitive media |
| Water and waste treatment: | Sludge pumping |
| Fishing industry: | Bulk fish transfer and effluent handling |
| Paint and pigment: | Dispersion mill feed and latex transfer |
| Pulp and paper: | Dyes, sizing agents, and titanium dioxide dosing |
| Mining: | Tailing slurries transfer, sludge transfer |
| Mineral processing: | Carbon and ceramic media transfer |
| Mineral Recovery: | Filter Press Feed, electro winning Feed |
| Ceramics: | Clay slip and glaze pumping |
| Construction: | Cements, coatings, spray concrete and aggregate pumping |
| Food and Beverage: | Yeast cropping, additives and effluent pumping reagents transfer and dosing, sump discharge |
KEY BENEFITS |
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| Energy efficiency: | Reductions in friction thanks to specially developed roller technology greatly reduces power consumption and mechanical wear. |
| Built for difficult applications: | AFX pumps can handle high abrasive slurries, corrosive material, high solids applications, gaseous liquids and very dense liquids and slurries with remarkable ease |
| Sensitive handling: | AFX pumps are Ideal for shear sensitive products |
| Chemically compatible: | Every AFX pump is supplied with internals to be chemically compatible with your product |
| Fool proof: | AFX series pumps can run dry indefinitely, without damage |
| Fully reversible: | Your AFX pump can easily change direction to flush or reverse transfer when necessary. |
| Minimal maintenance: | The heavy duty, high pressure hose is the only wearing item in your AFX pump. |
| Flexible to your needs: | Pump casings and internal components are available in a choice of materials including stainless steel |
| Suctions power: | The AFX pump is self-priming pump and has a suction lift capability of up to 9 metres |
| Accuracy: | AFX pumps have a fixed flow per revolution resulting in a highly accurate flow rate for dosage sensitive applications |
PUMP SELECTION
spreading from mining processes to chemical and agricultural testing laboratories as well as personal care and pharmaceutical laboratories, the need for this equipment is on the rise. Pilot plants and bench plants are small modular industrial systems, which are designed and implemented to generate information and understand particular behaviours during test or trial periods. This is usually done before building the large full-scale plant, which entails large capital outlays as well as major risks associated with the process. The use of the pilot or bench plants enables one to make a calculated and informed decision on whether or not to move forward with the full-scale operation. It equips the client with freedom to run tests accurately as well as change and modify procedures on the smaller scale.
BAFFLES AND BAFFLE COILS
Mounting bases and pedestals are critical in ensuring that the gearbox of the agitator is correctly aligned and mounted to the supporting beam structure. Our pedestals and bases are designed to significantly reduce the potential of twisting or flexing within the gearbox housing; which is often a common cause of some gearbox failures.IMPELLERS
Mixing technology represents a balance between the requirements of the process and the output efficiency of the impeller within the process. Often referred to as propellers, the impellers selected for a specific agitation system are required to produce one of three basic fluid regimes: Flow (Q), Shear (H) and Pressure (P); and there is also the possibility of producing a combination of the three.
IMPELLER TYPE: F3
IMPELLER TYPE: FS4
IMPELLER TYPE: P3
IMPELLER TYPE: P4
FOLDING IMPELLERS
IMPELLER TYPE: R6
FCE3 CLEAN EDGE IMPELLER
AFX has over 30 years' experience in the field of mixing technology. We have a broad range of quality process mixing systems and agitators to suit various industrial applications and provide solutions to all your manufacturing requirements.
PRESSURE OXIDATION
GAS DISPERSION
IRON REMOVAL
CYANIDE DETOX
PEDESTAL MOUNTED MIXERS
R6 PUMP IMPELLER
SIDE ENTRY AGITATORS
TOP ENTRY MIXERSGEARBOXES
On our larger agitators, gearboxes are designed to incorporate a dry well and heavy-duty output bearings. In the majority of instances, we also allow for an extended bearing distance. Normally, gearboxes are selected on torque alone, but with agitators, the overhung load is large, and the drive is subjected to high external loads. Our selection, therefore, doesn't only cater for the transmission of power, but also its ability to withstand external forces.
BASES
With tanks being larger, the structures the agitator needs to mount onto becomes more susceptible to inaccuracies and misalignment. With the intention of saving costs, many manufacturers allow their gearboxes to be bolted directly onto faulty beam structures. By mounting a machined gearbox directly onto a fabricated structure, it preloads the housing. This causes additional stress within the housing itself. During operation, this misalignment, combined with any twisting of the beams, will cause premature casing failure. AFX-designed gearbox bases have machine mounting surfaces that don't need shimming and won't preload the gearbox casing. Bases are designed to withstand much greater loads than what the agitator is subjected to. This enables the base to increase the rigidity of the structure.
Our range of portable top entry mixers suited to smaller mixing and blending applications provides the customer with the freedom to decide how to mount, move or permanently fix the agitator. Portable air or direct drive units are supplied with swivel brackets perfect for mounting at the desired angle. Some small direct and gear drive units can be wall mounted for applications with multiple containers. Angular mounted or angular offset agitators are commonly employed for use in cylindrical mixing vessels which are un-baffled. The portability of our small agitators gives good flexibility, allowing freedom to move from one vessel to another. Our applications engineers are on hand to advise the most suitable configuration for your needs, to ensure these versatile agitators offer the user the most economic mixing solution.
To eliminate potential design errors, AFX ensures that all its manufacturing drawings are produced in 3D. A process referred to as Finite Element Analysis (FEA) is used in instances where large, or infrequent components are designed. The analysis combines all the operating loads of the system, allowing the designer to see potential flaws before manufacturing takes place.
MOUNTING BASE
Mounting bases must accommodate machined gearbox bases and fabricated beam structures and prevent twisting and stressing of gearbox casings – a common cause of failure of proprietary drivers.
BEARING MEMBER
Bearing members often house mechanical seals or serve to isolate the gearbox from high bending moments. Accurate prediction of stress, movement and deflection are critical.
AFX makes use of Finite Element Analysis (FEA) for its designs allowing its engineers to model the combination of loads applied to the actual components resulting from the impeller’s rotation system and its interaction with fluids and slurries. By making use of this method, the applied bending moment, torque and thrust can be predicted and adequately accommodated in the design. Detailed FEA is required in instances where important components carry critical loading. Shown below are some examples of our FEA applications.
Computational Fluid Dynamics (CFD) is the method of applied mathematics, physics and computational software used to visualise how a gas or liquid flows, as well as how a gas or liquid affects certain objects as it flows past. AFX makes use of CFD in numerous applications to calibrate flow numbers, view velocity vectors and assist with solving process problems.
Agitator shafts are manufactured to a stringent straightness tolerance of 1mm/metre of shaft length.
We manufacture various types of impellers for different applications, including high viscosity blending.
Mounting bases are critical components in ensuring that the gearboxes are correctly aligned and mounted to the beams or structure.
These independent units are designed to accommodate all the loads and forces applied as a result of the mixing action.
Our pumps are at the forefront of peristaltic pumping technology. Developed to handle near impossible pumping applications, the AFX series pumps have become industry favourites.
SMALL TOP ENTRY AGITATORSOur range of portable top entry mixers suited to smaller mixing and blending applications provides the customer with the freedom to decide how to mount, move or permanently fix the agitator. Portable air or direct drive units are supplied with swivel brackets perfect for mounting at the desired angle. Some small direct and gear drive units can be wall mounted for applications with multiple containers. Angular mounted or angular offset agitators are commonly employed for use in cylindrical mixing vessels which are un-baffled. The portability of our small agitators gives good flexibility, allowing freedom to move from one vessel to another. Our applications engineers are on hand to advise the most suitable configuration for your needs, to ensure these versatile agitators offer the user the most economic mixing solution.
As the name suggests, these agitators are directly powered by the installed motor. Being a very cost-effective and quick agitator to supply, there are many small and easy blending applications where direct drive agitators are well suited. Using our range of F3 axial flow impellers, the agitator delivers on the process requirements. Most commonly used in small pilot and bench plants, pharmaceutical laboratories, test laboratories in research and development departments as well as in batch development within the personal care industry, these direct drives are adaptable, easy to use, require little maintenance and ensure that the desired process outcomes are met. Available with variable speed drives and various mountings, we are certain that we will meet your process solution.
As all mixing and blending applications differ, the demands placed on the agitator do too. In some applications, the use of a direct drive is just not possible for various mechanical reasons. Keeping this in mind, we offer small portable gear driven agitators. Sizing the agitator to suit your vessel as well as to ensure that the desired process is achieved, we strive to bring you the best top entry solutions. Tailoring our manufacturing methods, we can keep costs competitive and guarantee the best quality agitator. The majority of these units can be found in applications where a solid suspension is required, or the viscosity of the product is high within the vessels or where the mixing application is arduous. These agitators power a large segment of the market, where the demand has not waivered. Available with a selection of various options to ensure that the agitator is customised to suit your specific needs and process requirements, our range of AMX portables are a solution within the various markets, and they continue to expand their application reach.
AFX offers small electric or pneumatic agitators perfectly suited to small instant blending applications in 210-litre drums, where flash mixing and blending is required. Although designed primarily for 210-litre drums, these adaptable mixers can be easily adjusted to suit smaller containers by changing the shaft length. Two standard designs are available to suit both open and closed top drums. For closed top drums, agitators are supplied with a dual bladed folding impeller designed to fit through the bung hole on the top of the closed drum. The agitator comes complete with a threaded bung hole adaptor for mounting and operating purposes. For open top drums, agitators are usually supplied with our fixed three bladed F3 impellers. These units are cost-effective, efficient, easy to operate and maintain. Their portable design allows the freedom to move from one vessel to another. Operating between 300 – 3000 rpm. The wetted parts are manufactured from stainless steel and the aluminium housing aids the light-weight design of this agitator. These agitators are the number one solution for light drum mixing and blending applications.
AFX offers a range of Intermediate Bulk Container (IBC) mixers (also known as TOTE or flow bin mixers) specifically designed to handle mixing duties within the container. Our mixers handle varying ranges of viscosity, densities and other processing requirements. The main feature of AFX’s design is found in a range of folding impellers. These impellers are based on our range of high-efficiency hydrofoils that can fold in to facilitate fitting through the limited container opening, without the need for any modification to the container. The container openings vary from 100mm (4″) up to 200mm (8″). Our stainless steel impellers are available in varying diameters from 132mm (5,2″) up to 435mm (17,1″) which allows us to meet most application requirements. With the impeller being a hydrofoil the design offers the efficiencies of a fixed bladed impeller system. Our design results in lower power consumption compared to our competitors while maintaining the same results. This improves the process efficiencies and reduces the mechanical loading on the agitator. This reduced mechanical loading allows the agitator to be lightweight and durable.
TOP ENTRY MIXERS
The need for larger mixers has increased in recent years, mainly due to the industry’s requirement to expand operations, or to keep production costs as low as possible. At AFX, we customise our top entry mixers to accommodate your process. Our top entry mixers are available in different technical specifications and can be used for specific purposes across different industries. In the past, large top entry units were more commonplace in the mining industry. However, this trend is now changing with other industries now also requesting larger and more specialised mixers.
As agitators become larger, the loading requirements increase considerably, and every component is looked at individually, ensuring it is robust enough to handle the application. At AFX, all design work is further scrutinised using Finite Element Analysis (FEA) to ensure that failures do not occur. Many companies tend only to use FEA’s once they have experienced problems or failures. We use FEA’s and our design know-how to avoid problems before they happen.
Components are isolated and designed to handle loads far more than what they would experience during operation. Our software allows us to predict and simulate very accurately what loads will be experienced during operation. Even with this in mind, all our designs are conservative and can tolerate any fluctuating loads and peaks that the plant may experience. These components also have unique design features, such as:
GEARBOXES
On our larger agitators, gearboxes are designed to incorporate a dry well and heavy-duty output bearings. In the majority of instances, we also allow for an extended bearing distance. Normally, gearboxes are selected on torque alone, but with agitators, the overhung load is large, and the drive is subjected to high external loads. Our selection, therefore, doesn’t only cater for the transmission of power, but also its ability to withstand external forces.
BASES
With tanks being larger, the structures the agitator needs to mount onto becomes more susceptible to inaccuracies and misalignment. With the intention of saving costs, many manufacturers allow their gearboxes to be bolted directly onto faulty beam structures. By mounting a machined gearbox directly onto a fabricated structure, it preloads the housing. This causes additional stress within the housing itself. During operation, this misalignment, combined with any twisting of the beams, will cause premature casing failure. AFX-designed gearbox bases have machine mounting surfaces that don’t need shimming and won’t preload the gearbox casing. Bases are designed to withstand much greater loads than what the agitator is subjected to. This enables the base to increase the rigidity of the structure.
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