my business

my business

Ideas to help educate and encourage customers to take simple steps to reduce their consumption. Learn more about: Manage My Account, My Energy Portal and SaveNow programs and rebates. Get Energy Tips and Peak Energy Day information. Learn about Smart Thermostats and Upcoming CPS Energy Events. Use our Energy Cost Calculator.

Enroll in our Budget Payment Plan, and well average your bills over the past year, add a small percentage to cover environmental factors and changing fuel costs, then charge you the resulting amount each month

Our Veterans Discount Program provides electric bill payment assistance to those who have significantly decreased abilities to regulate their core body temperatures due to severe burns received during combat

We offer help to those who provide emergency response for our country to include Firefighters and Police. Our First Responders with Burn Injuries Discount Program provides electric bill payment assistance to those who have significantly decreased abilities to regulate their core body temperatures due to severe burn injuries sustained in the course of providing first responder duties.

Now introducing the redesigned Construction Renovation web portal. The new portal is user-friendly and easy to navigate. Most importantly, it will allow most customers to create and manage their construction projects online, regardless of the project type.

The 2021 edition of CPS Energys Electric Service Standards presents for the convenience of Electrical Contractors, Architects, Engineers, and others, the current standards and requirements for electric service and meter installations. It supersedes all previous editions of the Electric Service Standards. These service standards are intended to supplement the City of San Antonio Electrical Code, National Electrical Code, and National Electrical Safety Code, and to establish certain requirements that are based on experience for maintaining safe and reliable service for CPS Energy Customers.

The Damage Prevention Bill for Texas (House Bill 2295) took effect October 1998, and is known as Utilities Code Title 5, Chapter 251. This law requires most facility owners to join a notification (or one call) center and requires excavators to call 48 hours prior to digging. It also requires any notification or one call center operating in Texas to share messages they receive between the notification centers. This provision is to ensure that excavators need only make one call to notify most buried facility owners. The Dig Safely program was introduced nationwide in June 1999. Its purpose is to help protect underground utility lines from damage by excavators, and protect excavators from the effects of damage to underground lines.

CPS Energy by way of its electric and natural gas service contract with the General Service Administration (GSA) in Washington D.C. is a federal contractor. Consequently, we are required to report our contracting activity with large, small, minority, service-disabled, veteran, historically underutilized, HUBZone, and woman-owned businesses.

CRU is dedicated to increasing community awareness of and enrollment in assistance programs, educating customers about energy efficiency and safety, and working directly with customers with unique needs.

Requests for a new streetlight in an unincorporated area or another incorporated city in the CPS Energy service delivery area should be made through the local homeowner association or municipal government office.

Our Corporate College Internship Program (CCIP), is designed to meet the industrys rapidly changing workforce needs by providing local San Antonio college students with public utility career experience.

This year marks our 75th anniversary of being owned by the city of San Antonio. Thats 75 years of providing safe, reliable, and affordable electric and gas services to the Greater San Antonio community.

A new substation, transmission line(s) and associated distribution lines, north of San Antonio near US 281 and FM 1863, will provide additional electric capacity and improve the reliability of electric services to homes and businesses in this area.

As the electric and natural gas utility in the Greater San Antonio area, we are committed to providing reliable power, so customers lights and natural gas turn on quickly, operate safely and remain affordable. As such, we are committed to improving infrastructure to ensure we provide the highest level of customer service and reliability to our community.

Ideas to help educate and encourage customers to take simple steps to reduce their consumption. Learn more about: Manage My Account, My Energy Portal and SaveNow programs and rebates. Get Energy Tips and Peak Energy Day information. Learn about Smart Thermostats and Upcoming CPS Energy Events. Use our Energy Cost Calculator.

Now introducing the redesigned Construction Renovation web portal. The new portal is user-friendly and easy to navigate. Most importantly, it will allow most customers to create and manage their construction projects online, regardless of the project type.

Our customers are learning about a variety of new ways to generate clean, efficient energy, including distributed generation, which is smaller-scale power production located where the power is consumed. CPS Energy can help you install a distributed generation (DG) system on your home or business.

CPS Energy's distribution system can facilitate the delivery of the variety of communication services offered today. With a streamlined pole attachment process, we're dedicated to partnering with companies to assist with speed-to-market processes for future technologies. CPS Energys Pole Attachment Services Office is the single point of contact for all who wish to attach infrastructure to our distribution poles.

The 2021 edition of CPS Energys Electric Service Standards presents for the convenience of Electrical Contractors, Architects, Engineers, and others, the current standards and requirements for electric service and meter installations. It supersedes all previous editions of the Electric Service Standards. These service standards are intended to supplement the City of San Antonio Electrical Code, National Electrical Code, and National Electrical Safety Code, and to establish certain requirements that are based on experience for maintaining safe and reliable service for CPS Energy Customers.

The Damage Prevention Bill for Texas (House Bill 2295) took effect October 1998, and is known as Utilities Code Title 5, Chapter 251. This law requires most facility owners to join a notification (or one call) center and requires excavators to call 48 hours prior to digging. It also requires any notification or one call center operating in Texas to share messages they receive between the notification centers. This provision is to ensure that excavators need only make one call to notify most buried facility owners. The Dig Safely program was introduced nationwide in June 1999. Its purpose is to help protect underground utility lines from damage by excavators, and protect excavators from the effects of damage to underground lines.

CPS Energy is the nations largest municipally owned energy utility providing both natural gas and electric service. We serve more than 840,750 electric customers and 352,585 natural gas customers in and around San Antonio, the nations seventh largest city.

To maintain the overall health of our infrastructure and utility system, we have to occasionally close roads to perform upgrades, maintenance and replacements. The road closures below are scheduled but on occasion, we are forced to close roads to make unscheduled repairs to our equipment.

We are proud to be a part of SA Climate Ready, working with UTSA and the City of San Antonio. This project is to develop a Climate Action and Adaptation Plan for the City of San Antonio - exploring both mitigation strategies, aiming to reduce or prevent the emission of GHGs, and adaptation strategies aming to prepare the community, municipal government operations, and other key sectors for the unavoidable impacts of climate change.

The RAC is made up of 21 members comprised of 11 appointees by the CPS Energy Board of Trustees, including Mayoral appointees and 10 City Council appointees. Members of the RAC will devote the necessary time and energy to learn about the utility business and the rate design function that allows utilities to recover their costs to provide service. This effort will help them understand and provide thoughtful input and perspectives regarding CPS Energys rate structure and rate design options.

We continue to fight to protect customers from excessive fuel and purchased power costs from the February 2021 Winter Storm Uri. Stay up to date by following us onFacebookandTwitter. More updates:NewsroomandStorm Updates.

We stand ready to help any customer in need. Our People First philosophy led us to suspend disconnects while our community bands together during this challenging time. If you are experiencing financial hardship, we urge you to contact us for help. Call us at 210-353-2222 or online at cpsenergy.com/assistance.

We encourage the use of a face-covering at any CPS Energy facility. Our customer service center hours are 7:45 am to 5:00 pm. Monday-Friday. If you have tested positive, or a family member has tested positive for COVID-19 in the last 14 days, please use our online tools or call 210-353-2222 for assistance. Please do not visit our customer service center if you have COVID-19 symptoms.

what is boiler | types of boiler | how does a steam boiler work

what is boiler | types of boiler | how does a steam boiler work

Boiler in thermal power plant accumulates the steam and build up a pressure to expend it in turbine and convert thermal energy to mechanical energy. The generator which is connected to turbine converts the mechanical energy into electric energy.

In pulverized coal fired boiler,The coal is pulverized to a fine powder, so that less than 2 % is +300 micro meter and 70 75 % is below 75 microns. The pulverized coal is blown with part of the combustion air into boiler plant through a series of burner nozzles. Combustion takes place at temperature from 1300 1700 C, depending largely on coal grade.

The Feed water enters the boiler through the economizer tubes provided in the path of the flue gas. The feed water is heated in the economizer and then enters the boiler drum situated outside the furnace at the top of the Boiler.

The water is circulated in the tubes and converted into steam by gaining heat inside the furnace.The dry and saturated steam from the boiler drum then passes through the superheater section and finally available at the boiler outlet header.

Pulverized coal fire boiler has been the preferred method for solid fuel firing but in the last few years, fluidized bed combustion boilers have begun to disturb this equilibrium by offering reliable solutions in the areas not served well by pulverized fuel boiler.

When gas or air is passed through an inert bed of solid particles such as sand or limestonesupported on a fine grid or mesh, the particle are undisturbed at low velocity. As air velocity is gradually increased, a stage is reached when the individual particle are suspended in the air stream. With further increase in the velocity of the air, the particles attain a state of high turbulence. Under such conditions, the bed assumes the appearance of a fluid and exhibits the properties associated with a fluid and hence the name Fluidized Bed combustion.

If the sand or limestone in a fluidized state is heated to the ignition temperature of the coal and the coal is injected continuously into the bed, the fuel will burn rapidly and the bed attains a uniform temperature due to effective mixing.

AFBC is atmospheric fluidized bed combustion, where the furnace pressure is atmospheric pressure and velocity of fluidized air is in the range of 1.2 to 3.7 m/sec. The in-bed tubes carrying water generally act as the evaporator. The flue gas from the furnace pass over the superheater sections of the boiler flow past the economizer, the dust collector and the air preheater before being exhausted to atmosphere.

In this system, the fluidized velocity in circulating beds ranges from 3.7 to 9 m/sec and the flue gas is recirculated with a cyclone to capture the unburnt carbon. There are no steam generation tubes immersed in the bad. Generation and super heating of steam takes place in the convection section, water wall and at the exit of the riser.

In PFBC, a compressor supplies the forced draft (FD) air and the combustor is a pressure vessel. The heat release rate in the bad is proportional to the bed pressure and hence a deep bed is used to extract large amount of heat. This will improve the combustion efficiency. Steam generated from the heat in the fluidized bed is sent to asteam turbine and hot flue gases drive a power generating gas turbine.

A steam boiler is designed to absorb the maximum amount of heat released from the process of combustion. There are three way (Radiation, convection & Conduction) that heat is transfer in the boiler and relative percentage of each heat transfer within system boiler is dependent on the type of steam boiler, fuels and the designed transfer surface.

granulators - takraf gmbh

granulators - takraf gmbh

Coal granulators have undergone various important improvements over the years, but they still retain the original concept of a machine which sizes run-of-mine coal and removes tramp iron/debris at the same time. The ability of a granulator to continue operating reliably for decades has been the primary reason for its wide adoption in the international mining industry.

The range of granulators provided by TAKRAF are sold under license from Pennsylvania Crusher Corporation and are particularly suitable for the coal industry where they boast a solid reputation for quality, performance and a long and efficient service life. This efficient service life can be ascribed to their many unique features and systematic refinements to conventional crusher features. Granulators produce a sized product with a minimum of fines as their operating principle is quite unique. Unlike ordinary hammer mills, the coal is not shattered by hammers but broken up by floating rolling rings of hardened steel.

ring granulator type coal crusher - working principle,parts

ring granulator type coal crusher - working principle,parts

The crushing action is performed when material is dropped through the feed opening where it is struck,in mid air by the multiple rings which are being driven round by the rotor discs in direction towards the breaker plate. The rings are mounted on suspension bars as shown in the diagram. When the rotor is set in the motion centrifugal force brings the ring out against material to be crushed.

As material is fed to the machine the rings are forced back towards the rotor center until bar is encountered by the ring internal surface and a forward driving force is exerted.The material is broken and discharged through the cage bars or screen plates thus easing the load and allowing the ring to move out until it is held again by suspension bar before encountering the incoming feed once again.

The rings are thus held in deep contact with the bed of material on the cage bars or screen plates and they revolve with planet like motion relative to the direction of rotor rotation. This positive rolling feature provides a constant effective crushing action which in turn ensures a granular product sizing.The size of crushed coal is determined by size of hole in screen plate and clearance

Single tooth rings or plain rings or double tooth or a mixture of both are used to meet the particular crushing condition required and the ring granulator type crusher are the ideal machines for the minimum fines production.

Crusher frame are fabricated from heavy steel plates with large inspection front and rear doors, fitted with dust tight seals. Access for further maintenance is provided on the top. Doors on the sides above the rotor shaft facilitate removal of the rotor without completely dismantling the machine. Hydraulic door opening arrangement (optional) can be provided, if required.

Cage adjustment are require to adjust clearance between the cage screen and path of ring hammer. the Cage assembly can be easily moved by a ratchet wrench and worm gear assembly either towards or away from the path of crushing rings. Adjustment which can be made while the granulator is in operation, provides control over the product size within permissible limits. The cage hinge bearing is so located that in any adjusted position all parts of cage face are practically equidistant from the rotor assembly. This ensures even wear.

The granulator rotor assembly generally require minimum maintenance with the exception of hammer and suspension bar replacement. Frequency of hammer and suspension bar replacement will depend upon the material crushed and the rate it is fed. Preventive maintenance of rotor assembly include the following:

stone & coal crusher manufacturers, fuel & ring granulator coal crusher manufacturers

stone & coal crusher manufacturers, fuel & ring granulator coal crusher manufacturers

We at Ecoman India are stone crusher manufacturers, coal crusher manufacturers, Fuel (coal) crusher manufacturers, and Ring Granulator coal crusher manufacturers selling best product range across Indian and overseas markets. Our supreme range of products has wide application in mining, construction, and allied industries.

We are following strict quality guidelines while manufacturing our various types of crushers at our production house. Our crushers are remarkably suitable for grinding tough rocks, ore, lime stone, hard granite stones, river gravels, and coal etc.

To know more on to our product range and what makes us most reliable stone crusher manufacturers, coal crusher manufacturers, Fuel (coal) crusher manufacturers, and Ring Granulator coal crusher manufacturers, contact us right now.

This is to certify that ECOMAN's Jaw Crusher of size 36" x 24" is working satisfactorily, at our site at Bhuj, for last three years. It is giving rated outputs without any failures. Their service is efficient & prompt.

granulators - an overview | sciencedirect topics

granulators - an overview | sciencedirect topics

Granulators are essentially rotary grinders that are used to grind scrap parts and melt delivery systems (sprues and runners) into feedstock sized granules for reprocessing. This allows the molder to reduce waste and produce components more cost effectively. Since these granulators will be used to cut polymers that are loaded with metal powders, the wear of the cutting blades is great. As such, the blades should be manufactured from carbide or a tool steel with high wear resistance. A design that allows resharpening of blades is desirable. Many granulators are designed so that the blades must be completely replaced when they are worn. The last consideration with respect to granulators is to have a granulator that is easy to clean thoroughly to avoid cross contamination between MIM materials. Having a granulator to serve each material may be desirable.

1.What are the different rotor designs used in granulators?2.What determines the size of the granulated particles?3.Where are granulators used in extrusion?4.What are four maintenance issues associated with granulators?5.What needs to be checked and serviced in a good preventive maintenance program for granulators?6.What is the difference between a granulator used to regrind film compared to a granulator designed to regrind profiles, pipe, and heavy stock?7.What are the differences in knives required for different resins?

Granulator machines are designed with high speed, medium inertia, open rotor body for fine grinding, with two, three, or five hardened steel knives. Granulators can grind material down to 0.177mm (80 meshes) or up to 5cm in size. Generally, the resulting particles vary in size from 3 to 20mm. Interchangeable qualifying screens with various diameter holes determine the final reduction size. With decibel ratings of less than 65Db, these units are ideal for placement at individual workstations. Granulators are sized by the dimensions of the cutting chamber and range in size from 20 25 to 40 88cm. Motor sizes range from 5 to 40HP. Complete systems can include air discharge units or conveyors, and can easily be integrated with existing shredder or grinder systems. Granulators have a smaller footprint than a full-sized grinder, but can still handle high volumes of product in the granulation process (Fig. 3.13) [68]. Hammer mills accomplish size reduction by typically impacting at rates of 7000rpm and higher [16]. A solid rotor for grinding scrap Cu wires, PCBs, metals, and plastics is used. These granulators are used for the sizing of plastics, nonferrous metals, heterogeneous materials, and enable to reach controlled output size in the recycling process with the use of classifier screens starting from 2mm diameter. The size of the granulators ranges between (1060 1800) (1700 1800) (2000) mm; power from 8 to 90kW, and weight from 0.7 to 4.2 tons.

Roll granulator, an indispensable basic production link of a large number of industrial and agricultural products, is involved in a wide range of national economy. Roll granulator is also a big energy consumer, and the pollution caused by working process is an important source of environmental pollution in China. Therefore the evaluation and optimization of the roll granulator design process is of great significance to both the manufacturers and the consumers.

The authors investigated the design, manufacture, and service process of a roll granulator in a building material equipment manufacturing group. It is a high-tech group, which manufactures large complex building material equipment for cement production line, such as cement mill, preheater system, rotary kiln, and stacker reclaimer. Due to complex structure, harsh working environment, long production cycle, and distributed manufacturing mode, it is difficult to implement the informatization construction of the building materials and equipment group. The development of new IT technologies brings opportunities for the group, which has established a complete data collection, mining, and analysis system around the PLC.

Take the roll granulator as an example, product design, manufacturing, and service mode of the group is shown in Fig. 5.5. When the company receives the order, the technician uses CAD and SolidWorks to design drawings according to customer requirements and imports the product design parameters, processing parameters, and material requirements into the enterprise resource plan (ERP) system through the product data management (PDM) system. Then, the production department organizes production according to the production details. IoT technology is used to collect real-time processing data of equipment and performance test data of products, while handheld terminals are used to collect progress data and quality inspection data. When all the components are processed, they are transported to the construction site for installation. When the product is put into use, the sensors and control system will collect the equipment operation data (such as energy consumption, vibration, and breakdown parameters) in real time and will upload it to the cloud platform. In addition, during the use and maintenance process, the customer also employs the after-sales service system to report problems and evaluations to the group and obtains continuous improvement. In this way, a large amount of data in PLC is collected and stored on the cloud platform for real-time monitoring and analysis. New IT has injected fresh energy to large complex equipment life cycle. These data will help build the DT for roll granulator and support designer for design evaluation.

The TSG consists of a barrel enclosing two co- rotating self-wiping screws. At the entrance, raw materials are fed into the transport zone and the granulation liquid is added via two nozzles, one for each screw, before the material reaches the mixing zone which consists of kneading discs (Fig. 1). The powder is hence wetted by the granulation liquid in this region. Further down, since the granulation occurs by a combination of capillary and viscous forces binding particles in the wet state, the wetted material is distributed, compacted and elongated by the kneading discs of the mixing zones, changing the particle morphology from small (microstructure) to large (macrostructure) (Vercruysse et al., 2012). The rotation of the screws conveys the material in axial direction through the different zones of the TSG by the drag and flow-induced displacement forces and thus causing mixing and granulation. The rheological behaviour of the material also changes based on liquid-to-solid ratio (L/S) (Althaus and Windhab, 2012).

Ring granulator crushers are used for coal crushing to a size that would be acceptable to or suitable for the mills/pulverizers, which then convert it into powdered coal. The essence of using a ring granulator is that it prevents both oversize and undersize coal; this helps with the quality of finished product and improves its workability. Due to the crushers strong construction, it is capable of being utilized for crushing various materials (e.g.,coal, limestone, lignite, gypsum) and other medium-to-hard friable items. Ring granulators are rugged and dependable and specially designed for continuous high-capacity crushing of materials. They are available with operating capacities from 40 to 1800 tons/hr or even more, with feed size of up to 500 mm.

Adjustment of clearance between the cage and the path of the rings is provided to take care of product gradation as well as to compensate for wear and tear of the machine parts and to maintain product size. The unique combination of impact and rolling compression makes the crushing action yield a higher output with less power consumption and a lower noise level. Here, the product is almost of uniform granular size with an adjustable range of <20 to 25 mm, and because the crushing action involves minimum attrition, minimum fines result. Further development from the conventional hammer mill through replacement of hammers by rings makes it possible to minimize both oversize and fines, thereby improving efficiency.

Ring granulator crushers work on an operating principle similar to a hammer mill, where the only change is that the hammers are replaced with rolling rings. This crusher compresses material by impact in association with shear and compression force. It is comprised of a screen plate/cage bar steel box with an opening in the top cover to introduce the material. The power-driven horizontal main shaft passes from frame side to frame side and supports a number of circular discs fixed at regular intervals along its length within the frame.

There are quite a few bars running parallel to the main shaft and around the periphery that pass through these discs near their outer edges. The bars are uniformly located about the center of the main rotating shaft. There are a series of rings, between the two consecutive disc spaces, mounted on each bar that are free to rotate on the bars irrespective of main shaft rotation.

The entire cage assembly, located below the rotor assembly, can be set at a desired close proximity to the rings by a screw jack mechanism that is adjustable from outside of the crusher frame. The rotor assembly, consisting of the shaft, discs, rings, etc., is fixed as far as the main shaft center line is concerned. This main shaft is carried in roller bearings from the box sides. The movable cage frame arrangement is provided so as to set its inner radius marginally larger than that of the ring running periphery.

When coal is fed from the top, the rings also rotate along with the shaft and around their own center line along the bars, which drag coal lumps and crush them to the desired size. After the coal has been crushed by ring granulator crusher, a vibrating screen grades the coal by size and then transports it via a belt conveyor. In this process, a dewatering screen to remove water from the product is optional.

The granulator consists of a granulation chamber, where the particle population is fluidized through an air stream with predefined pressure, temperature and humidity. Then a liquid solution or suspension is injected, which settles on the particles. Due to the low humidity and increased temperature the liquid fraction, i.e. the solvent or the external phase, is evaporated. The remaining solid forms a new layer on the particle surface. Typically, nucleation due to spray drying, particle agglomeration and breakage are in this configuration negligible. As one is in general interested in product particles with a defined particle size distribution withdrawn granules have to be sieved, which results in two additional fractions. The fine particles are directly sent back to the granulation chamber, whereas the oversized granules are send to a mill. There they are grinded to a specific size and then send back to the granulation chamber. It should be mentioned that due to this sieve-mill cycle a permanent generation of new particles is guaranteed, which hence allows a continuous process operation. The associated pilot plant and process scheme is depicted in Figure 1 (left and right). In Heinrich et al. (2002) a population balance model for the fluidized bed spray granulation with external product classification has been presented. There, it was assumed that the particles are almost spherical and can hence be described by one internal coordinate L, the particle diameter, giving rise to the particle size distribution n(t, L). The associated particle growth can be described by

In the continuous configuration of the fluidized bed spray granulation particles are continuously removed in order to achieve a constant bed mass, which correlates to a constant third moment of the particle size distribution. The particle flux being removed from the granulator is

where K is the drain, which has to be controlled such that the bed mass is constant. The removed particles nout(t,L) are then sieved in two sieves and separated into three classes: fines fraction Eq. (3), i.e. particles which are smaller than the desired product, product fraction Eq. (4), i.e. particles with the desired size and oversize fraction Eq. (5), i.e. particles being bigger than the desired product.

As has been shown in Radichkov et al. (2006) the qualitative dynamical behavior of the fluidized bed spray granulation with external product classification strongly depends on the process parameters especially the mill grade M.For sufficiently high mill grade, transition processes decay and the particle size distribution reaches as table steady state (Figure 2 left). Decreasing the mill grade below a critical value gives rise to nonlinear oscillations (Figure 2 right). Using the population balance model the critical mill grade, i.e. the mill grade where the qualitative change in the stability behavior occurs, can be derived by a one-parameter bifurcation analysis as depicted in Figure 3. It is important to mention that this qualitative behavior is not induced by the specific model formulation but is directly connected to the presented process configuration.

A ring granulator works on n operating principle similar to a hammer mill, but the hammers are replaced with rolling rings. The ring granulator compresses material by impact in association with shear and compression force. It comprises a screen plate/cage bar steel box with an opening in the top cover for feeding. The power-driven horizontal main shaft passes from frame side to frame side, supporting a number of circular discs fixed at regular intervals across its length within the frame. There are quite a few bars running parallel to the main shaft and around the periphery that pass through these discs near their outer edges. The bars are uniformly located about the center of the main rotating shaft. There are a series of rings in between the two consecutive disc spaces, mounted on each bar. They are free to rotate on the bars irrespective of the main shaft rotation. The entire cage assembly, located below the rotor assembly, can be set at a desired close proximity to the rings by screw jack mechanism adjustable from outside the crusher frame. The rotor assembly consisting of the shaft, discs, rings, etc., is fixed as far as the main shaft center line is concerned. This main shaft carries in roller bearings from the box sides. The movable cage frame arrangement is provided so as to set its inner radius marginally larger than that of the ring running periphery. When coal is fed from the top, the rings also rotate along with the shaft and around their own center line along the bars, which drags coal lumps and crushes them to the desired size. After the coal has been crushed by the coal crusher, a vibrating screen grades the coal by size and the coal is then transported via belt conveyor. In this process, a dewatering screen is optional to remove water from the product.

The feeder-blender-granulator system (see Figure 1a) consists of two feeders (API + excipient) that feed into a blender where the API and excipient are mixed due to convective/diffusive forces. The mixture of API/excipient is then continuously transported into a granulator whereby through the addition of liquid binder, the particles are formed into larger granules, to improve its flow and dissolution properties.

Each continuous feeder operates under closed-loop proportional-integral (PI) control whereby the feedrate is specified as the set-point and the feeder RPM is manipulated to ensure that the set-point is met. To model each feeder, set-point changes were made to the feedrate and the dynamic response was observed to follow a first order profile. Therefore, a first-order plus time delay (FOPDT) model was used to fit the data.

Here r is the vector of internal variables used to characterize the distribution and z is the vector of external coordinates used to depict spatial position. F(z,r,t) is the population distribution function (a.k.a. the number density function). The term r[F(z,r,t)drdt] would account for the rate at which the distribution evolves with respect to position and time due to the rate of consolidation. The term z[F(z,r,t)dzdt] accounts for the evolution of the distribution of the particle population with respect to spatial position. The function Rformation(z,r,t) and Rdepletion(z,r,t) accounts for the formation and depletion of particles respectively due to discrete aggregation and breakage phenomena. In the blender model, aggregation and breakage are neglected; therefore the PBM reduces to a two-dimensional model with respect to the vector z where z denotes the axial and radial direction. In the granulation model, the granulator is assumed to be well-mixed; therefore the PBM is a four-dimensional model with respect to r, where r denotes the volume fractions of the API, excipient, liquid and gas. Details of the blending model and granulation model can be found in [56].

Figure 2a depicts the total mass flowrate of powder that exits the blender and enters the granulator. It can be seen that steady state is reached by t=150s, whereby a step change is introduced to the rpm (rpm is doubled). This results in a sharp increase in the mass flow rate which gradually reduces to the original mass flowrate. Figure 2b depicts the average granule diameter upon particles exiting the granulator. It can be seen that in the first few seconds of operation, no powder enters the granulator as they are still being processed in the blender. Upon powder entering the granulator, there is a sharp increase in granule diameter as granules undergo aggregation and eventually a steady state is attained by t=150s, whereby the step change in rpm results in a slight immediate decrease in granule diameter (due to the sudden influx of more fine powder in the granulator). Eventually, this leads to more fine powder being aggregated and this results in an increase in granule diameter till a new steady state is achieved. Similar transient profiles are achieved for granule bulk density and granule API concentration (see Figures 2c and 2d)

A bimaterial catalyst support was obtained in a pan granulator with a composite sol-gel formulation based on -Al2O3 filler, boehmite binder and -Al2O3 beads. The resultant catalyst support shows a homogenous coating with a twenty micrometer thickness. Local mechanical properties of coating and interface are in the magnitude order of conventional -Al2O3 beads. Deposited metallic palladium nano-particles on this bimaterial are very preferentially located into the -Al2O3 coating as expected. Activity and selectivity of the bi-material catalyst show a huge improvement compared to the reference catalyst using conventional carrier.

This study demonstrated that bi-material catalyst are promising candidate for all industrial catalytic reactions that present intraparticular diffusion limitations as mechanical properties and catalytic performances are very satisfactory. It should be planned in the future to extend the concept to multifunctional catalysis.

ring hammer balancing process - coal handling plants

ring hammer balancing process - coal handling plants

22.50, 22.30, 22.00, 22.10, 22.80, 22.40, 23.00, 22.10, 22.40,23.10, 23.20, 22.50, 22.80, 23.90,23.40, 22.70, 22.40, 22.80, 23.50, 23.60, 22.70, 23.30, 22.60, 22.60, 23.20, 21.20, 22.00, 21.50, 22.40, 22.10, 21.90, 21.60,22.60, 22.00, 23.50, 22.40, 21.80, 21.60, 22.90, 22.50, 23.50, 23.60, 22.50,22.40, 23.00, 22.00, 23.50, 22.60, 22.80, 22.40, 22.40, 22.20, 23.50, 21.90, 22.60, 23.50, 22.70, 23.00, 21.80, 21.20, 21.60, 22.70, 22.70, 22.60, 22.90, 22.80, 22.90, 22.80, 23.00, 22.80, 22.50, 23.20, 23.00, 21.60, 23.5, 23.00

23.90, 23.60, 23.60, 23.50, 23.50, 23.50, 23.50, 23.50, 23.50, 23.50, 23.40, 23.30, 23.20, 23.20, 23.20, 23.10, 23.00, 23.00, 23.00, 23.00, 23.00, 23.00, 22.90, 22.90, 22.90, 22.80, 22.80, 22.80, 22.80, 22.80, 22.80, 22.80, 22.70, 22.70, 22.70, 22.70, 22.70, 22.60, 22.60, 22.60, 22.60, 22.60, 22.60, 22.50, 22.50, 22.50, 22.50, 22.50, 22.40, 22.40, 22.40, 22.40, 22.40, 22.40, 22.40, 22.40, 22.30, 22.20, 22.10, 22.10, 22.10, 22.00, 22.00, 22.00, 22.00, 21.90, 21.90, 21.80, 21.80, 21.60, 21.60, 21.60, 21.60, 21.50, 21.20, 21.20

In fig. 2 we can see that the opposite rows C and D ring hammer weight sum are equal so these opposite rows are balanced. But the total weight sum of opposite rows A and B are not equal so we need to interchange the ring hammer between these opposite rows. The process of interchanging the ring hammer is mention below

We have to interchange one or more ring hammer from each unbalance rows in such a way that the difference between two unbalance rows hammer weight is equal or approx to balancing weight and choose heavy weight from the row which have positive balanced weight.

crushers - an overview | sciencedirect topics

crushers - an overview | sciencedirect topics

This crusher developed by Jaques (now Terex Mineral Processing Solutions) has several internal chamber configurations available depending on the abrasiveness of the ore. Examples include the Rock on Rock, Rock on Anvil and Shoe and Anvil configurations (Figure 6.26). These units typically operate with 5 to 6 steel impellers or hammers, with a ring of thin anvils. Rock is hit or accelerated to impact on the anvils, after which the broken fragments freefall into the discharge chute and onto a product conveyor belt. This impact size reduction process was modeled by Kojovic (1996) and Djordjevic et al. (2003) using rotor dimensions and speed, and rock breakage characteristics measured in the laboratory. The model was also extended to the Barmac crushers (Napier-Munn et al., 1996).

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100 mm in size. They are classified as jaw, gyratory and cone crushers based on compression, cutter mill based on shear and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing of hard metal scrap for different hard metal recycling processes.

Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor and crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough pass through the openings of the grating or screen. The size of product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around of the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions.

A design for a hammer crusher (Figure 2.6) allows essentially a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, circulation of suspended matter in the gas between A- and B-zones is established and high pressure of air in the discharging unit of crusher is reduced.

Crushers are widely used as a primary stage to produce the particulate product finer than about 50100mm. They are classified as jaw, gyratory, and cone crushers based on compression, cutter mill based on shear, and hammer crusher based on impact.

A jaw crusher consists essentially of two crushing plates, inclined to each other forming a horizontal opening by their lower borders. Material is crushed between a fixed and a movable plate by reciprocating pressure until the crushed product becomes small enough to pass through the gap between the crushing plates. Jaw crushers find a wide application for brittle materials. For example, they are used for comminution of porous copper cake. A Fritsch jaw crusher with maximal feed size 95mm, final fineness (depends on gap setting) 0.315mm, and maximal continuous throughput 250Kg/h is shown in Fig. 2.8.

A gyratory crusher includes a solid cone set on a revolving shaft and placed within a hollow body, which has conical or vertical sloping sides. Material is crushed when the crushing surfaces approach each other and the crushed products fall through the discharging opening.

Hammer crushers are used either as a one-step primary crusher or as a secondary crusher for products from a primary crusher. They are widely used for crushing hard metal scrap for different hard metal recycling processes. Pivoted hammers are pendulous, mounted on the horizontal axes symmetrically located along the perimeter of a rotor. Crushing takes place by the impact of material pieces with the high speed moving hammers and by contact with breaker plates. A cylindrical grating or screen is placed beneath the rotor. Materials are reduced to a size small enough to pass through the openings of the grating or screen. The size of the product can be regulated by changing the spacing of the grate bars or the opening of the screen.

The feature of the hammer crushers is the appearance of elevated pressure of air in the discharging unit of the crusher and underpressure in the zone around the shaft close to the inside surface of the body side walls. Thus, the hammer crushers also act as high-pressure, forced-draught fans. This may lead to environmental pollution and product losses in fine powder fractions. A design for a hammer crusher (Fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit [5]. The A-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the B-zone around the shaft close to the inside surface of body side walls. As a result, the circulation of suspended matter in the gas between A and B zones is established and the high pressure of air in the discharging unit of crusher is reduced.

Secondary coal crusher: Used when the coal coming from the supplier is large enough to be handled by a single crusher. The primary crusher converts the feed size to one that is acceptable to the secondary crusher.

The main sources of RA are either from construction and ready mixed concrete sites, demolition sites or from roads. The demolition sites produce a heterogeneous material, whereas ready mixed concrete or prefabricated concrete plants produce a more homogeneous material. RAs are mainly produced in fixed crushing plant around big cities where CDWs are available. However, for roads and to reduce transportation cost, mobile crushing installations are used.

The materiel for RA manufacturing does not differ from that of producing NA in quarries. However, it should be more robust to resist wear, and it handles large blocks of up to 1m. The main difference is that RAs need the elimination of contaminants such as wood, joint sealants, plastics, and steel which should be removed with blast of air for light materials and electro-magnets for steel. The materials are first separated from other undesired materials then treated by washing and air to take out contamination. The quality and grading of aggregates depend on the choice of the crusher type.

Jaw crusher: The material is crushed between a fixed jaw and a mobile jaw. The feed is subjected to repeated pressure as it passes downwards and is progressively reduced in size until it is small enough to pass out of the crushing chamber. This crusher produces less fines but the aggregates have a more elongated form.

Hammer (impact) crusher: The feed is fragmented by kinetic energy introduced by a rotating mass (the rotor) which projects the material against a fixed surface causing it to shatter causing further particle size reduction. This crusher produces more rounded shape.

Jaw crushers are mainly used as primary crushers to produce material that can be transported by belt conveyors to the next crushing stages. The crushing process takes place between a fixed jaw and a moving jaw. The moving jaw dies are mounted on a pitman that has a reciprocating motion. The jaw dies must be replaced regularly due to wear. Figure 8.1 shows two basic types of jaw crushers: single toggle and double toggle. In the single toggle jaw crusher, an eccentric shaft is installed on the top of the crusher. Shaft rotation causes, along with the toggle plate, a compressive action of the moving jaw. A double toggle crusher has, basically, two shafts and two toggle plates. The first shaft is a pivoting shaft on the top of the crusher, while the other is an eccentric shaft that drives both toggle plates. The moving jaw has a pure reciprocating motion toward the fixed jaw. The crushing force is doubled compared to single toggle crushers and it can crush very hard ores. The jaw crusher is reliable and robust and therefore quite popular in primary crushing plants. The capacity of jaw crushers is limited, so they are typically used for small or medium projects up to approximately 1600t/h. Vibrating screens are often placed ahead of the jaw crushers to remove undersize material, or scalp the feed, and thereby increase the capacity of the primary crushing operation.

Both cone and gyratory crushers, as shown in Figure 8.2, have an oscillating shaft. The material is crushed in a crushing cavity, between an external fixed element (bowl liner) and an internal moving element (mantle) mounted on the oscillating shaft assembly. An eccentric shaft rotated by a gear and pinion produces the oscillating movement of the main shaft. The eccentricity causes the cone head to oscillate between the open side setting (o.s.s.) and closed side setting (c.s.s.). In addition to c.s.s., eccentricity is one of the major factors that determine the capacity of gyratory and cone crushers. The fragmentation of the material results from the continuous compression that takes place between the mantle and bowl liners. An additional crushing effect occurs between the compressed particles, resulting in less wear of the liners. This is also called interparticle crushing. The gyratory crushers are equipped with a hydraulic setting adjustment system, which adjusts c.s.s. and thus affects product size distribution. Depending on cone type, the c.s.s. setting can be adjusted in two ways. The first way is by rotating the bowl against the threads so that the vertical position of the outer wear part (concave) is changed. One advantage of this adjustment type is that the liners wear more evenly. Another principle of setting adjustment is by lifting/lowering the main shaft. An advantage of this is that adjustment can be done continuously under load. To optimize operating costs and improve the product shape, as a rule of thumb, it is recommended that cones always be choke-fed, meaning that the cavity should be as full of rock material as possible. This can be easily achieved by using a stockpile or a silo to regulate the inevitable fluctuation of feed material flow. Level monitoring devices that detect the maximum and minimum levels of the material are used to start and stop the feed of material to the crusher as needed.

Primary gyratory crushers are used in the primary crushing stage. Compared to the cone type crusher, a gyratory crusher has a crushing chamber designed to accept feed material of a relatively large size in relation to the mantle diameter. The primary gyratory crusher offers high capacity thanks to its generously dimensioned circular discharge opening (which provides a much larger area than that of the jaw crusher) and the continuous operation principle (while the reciprocating motion of the jaw crusher produces a batch crushing action). The gyratory crusher has capacities starting from 1200 to above 5000t/h. To have a feed opening corresponding to that of a jaw crusher, the primary gyratory crusher must be much taller and heavier. Therefore, primary gyratories require quite a massive foundation.

The cone crusher is a modified gyratory crusher. The essential difference is that the shorter spindle of the cone crusher is not suspended, as in the gyratory, but is supported in a curved, universal bearing below the gyratory head or cone (Figure 8.2). Power is transmitted from the source to the countershaft to a V-belt or direct drive. The countershaft has a bevel pinion pressed and keyed to it and drives the gear on the eccentric assembly. The eccentric assembly has a tapered, offset bore and provides the means whereby the head and main shaft follow an eccentric path during each cycle of rotation. Cone crushers are used for intermediate and fine crushing after primary crushing. The key factor for the performance of a cone type secondary crusher is the profile of the crushing chamber or cavity. Therefore, there is normally a range of standard cavities available for each crusher, to allow selection of the appropriate cavity for the feed material in question.

Roll crushers are arbitrarily divided into light and heavy duty crushers. The diameters of the light duty crushers vary between 228 and 760mm with face lengths between 250 and 460mm. The spring pressure for light duty rolls varies between 1.1 and 5.6kg/m. The heavy duty crusher diameters range between 900 and 1000mm with face length between 300 and 610mm. In general, the spring pressures of the heavy duty rolls range between 7 and 60kg/m. The light duty rolls are designed to operate at faster speeds compared to heavy duty rolls that are designed to operate at lower speeds.

It has been stressed that the coal supplier should initially crush the materials to a maximum size such as 300 mm, but they may be something else depending on the agreement or coal tie up. To circumvent the situation, the CHP keeps a crushing provision so that coal bunkers receive the materials at a maximum size of about 2025 mm.

The unloaded coal in the hoppers is transferred to the crusher house through belt conveyors with different stopovers in between such as the penthouse, transfer points, etc., depending on the CHP layout.

Suspended magnets for the removal of tramp iron pieces and metal detectors for identifying nonferrous materials are provided at strategic points to intercept unacceptable materials before they reach the crushers. There may be arrangements for manual stone picking from the conveyors, as suitable. Crushed coal is then sent directly to the stockyard.

A coal-sampling unit is provided for uncrushed coal. Online coal analyzers are also available, but they are a costly item. Screens (vibrating grizzly or rollers) are provided at the upstream of the crushers to sort out the smaller sizes as stipulated, and larger pieces are guided to the crushers.

Appropriate types of isolation gates, for example, rod or rack and pinion gates, are provided before screens to isolate one set of crushers/screens to carry on maintenance work without affecting the operation of other streams.

Vibrating grizzly or roller screens are provided upstream of the crushers for less than 25 (typical) mm coal particles bypass the crusher and coal size more than 25 mm then fed to the crushers. The crushed coal is either fed to the coal bunkers of the boilers or discharged to the coal stockyard through conveyors and transfer points, if any.

This is used for crushing and breaking large coal in the first step of coal crushing plant applied most widely in coal crushing industry. Jaw crushers are designed for primary crushing of hard rocks without rubbing and with minimum dust. Jaw crushers may be utilized for materials such as coal, granite, basalt, river gravel, bauxite, marble, slag, hard rock, limestone, iron ore, magazine ore, etc., within a pressure resistance strength of 200 MPa. Jaw crushers are characterized for different features such as a simple structure, easy maintenance, low cost, high crushing ratio, and high resistance to friction/abrasion/compression with a longer operating lifespan.

Fixed and movable jaw plates are the two main components. A motor-driven eccentric shaft through suitable hardware makes the movable jaw plate travel in a regulated track and hit the materials in the crushing chamber comprising a fixed-jaw plate to assert compression force for crushing.

A coal hammer crusher is developed for materials having pressure-resistance strength over 100 Mpa and humidity not more than 15%. A hammer crusher is suitable for mid-hard and light erosive materials such as coal, salt, chalk, gypsum, limestone, etc.

Hammer mills are primarily steel drums that contain a vertical or horizontal cross-shaped rotor mounted with pivoting hammers that can freely swing on either end of the cross. While the material is fed into the feed hopper, the rotor placed inside the drum is spun at a high speed. Thereafter, the hammers on the ends of the rotating cross thrust the material, thereby shredding and expelling it through the screens fitted in the drum.

Ring granulators are used for crushing coal to a size acceptable to the mills for conversion to powdered coal. A ring granulator prevents both the oversizing and undersizing of coal, helping the quality of the finished product and improving the workability. Due to its strong construction, a ring granulator is capable of crushing coal, limestone, lignite, or gypsum as well as other medium-to-hard friable items. Ring granulators are rugged, dependable, and specially designed for continuous high capacity crushing of materials. Ring granulators are available with operating capacities from 40 to 1800 tons/h or even more with a feed size up to 500 mm. Adjustment of clearance between the cage and the path of the rings takes care of the product gradation as well as compensates for wear and tear of the machine parts for maintaining product size. The unique combination of impact and rolling compression makes the crushing action yield a higher output with a lower noise level and power consumption. Here, the product is almost of uniform granular size with n adjustable range of less than 2025 mm. As the crushing action involves minimum attrition, thereby minimum fines are produced with improving efficiency.

A ring granulator works on n operating principle similar to a hammer mill, but the hammers are replaced with rolling rings. The ring granulator compresses material by impact in association with shear and compression force. It comprises a screen plate/cage bar steel box with an opening in the top cover for feeding. The power-driven horizontal main shaft passes from frame side to frame side, supporting a number of circular discs fixed at regular intervals across its length within the frame. There are quite a few bars running parallel to the main shaft and around the periphery that pass through these discs near their outer edges. The bars are uniformly located about the center of the main rotating shaft. There are a series of rings in between the two consecutive disc spaces, mounted on each bar. They are free to rotate on the bars irrespective of the main shaft rotation. The entire cage assembly, located below the rotor assembly, can be set at a desired close proximity to the rings by screw jack mechanism adjustable from outside the crusher frame. The rotor assembly consisting of the shaft, discs, rings, etc., is fixed as far as the main shaft center line is concerned. This main shaft carries in roller bearings from the box sides. The movable cage frame arrangement is provided so as to set its inner radius marginally larger than that of the ring running periphery. When coal is fed from the top, the rings also rotate along with the shaft and around their own center line along the bars, which drags coal lumps and crushes them to the desired size. After the coal has been crushed by the coal crusher, a vibrating screen grades the coal by size and the coal is then transported via belt conveyor. In this process, a dewatering screen is optional to remove water from the product.

Crusher machines are used for crushing of a wide variety of materials in the mining, iron and steel, and quarry industries. In quarry industry, they are used for crushing of rocks into granites for road-building and civil works. Crusher machines are equipped with a pair of crusher jaws namely; fixed jaws and swing jaws. Both jaws are fixed in a vertical position at the front end of a hollow rectangular frame of crushing machine as shown in Fig.10.1. The swing jaw is moved against the fixed jaws through knuckle action by the rising and falling of a second lever (pitman) carried by eccentric shaft. The vertical movement is then horizontally fixed to the jaw by double toggle plates. Because the jaw is pivoted at the top, the throw is greatest at the discharge, preventing chocking.

The crushing force is produced by an eccentric shaft. Then it is transferred to the crushing zone via a toggle plate system and supported by the back wall of the housing of the machine. Spring-pulling rods keep the whole system in a condition of no positive connection. Centrifugal masses on the eccentric shaft serve as compensation for heavy loads. A flywheel is provided in the form of a pulley. Due to the favorable angle of dip between the crushing jaws, the feeding material can be reduced directly after entering the machine. The final grain size distribution is influenced by both the adjustable crusher setting and the suitability of the tooth form selected for the crushing plates.

Thus, the crusher jaws must be hard and tough enough to crush rock and meet the impact action generated by the action of swing jaws respectively. If the jaws are hard, it will be efficient in crushing rock but it will be susceptible to fracture failure. On the other hand, if the jaws are tough, the teeth will worn out very fast, but it will be able to withstand fracture failure. Thus, crusher jaws are made of highly wear-resistant austenitic manganese steel casting, which combines both high toughness and good resistance to wear.

Austenitic manganese steel was invented by Sir Robert Hadfield in 1882 and was first granted patented in Britain in 1883 with patent number 200. The first United States patents, numbers 303150 and 303151, were granted in 1884. In accordance with ASTM A128 specification, the basic chemical composition of Hadfield steel is 1%1.4% carbon and 11%14% manganese. However, the manganese to carbon ratio is optimum at 10:1 to ensure an austenitic microstructure after quenching [2]. Austenitic manganese steels possess unique resistance to impact and abrasion wears. They exhibit high levels of ductility and toughness, slow crack propagation rates, and a high rate of work-hardening resulting in superior wear resistance in comparison with other potentially competitive materials [310]. These unique properties have made Hadfield's austenitic manganese steel an engineering material of choice for use in heavy industries, such as earth moving, mining, quarrying, oil and gas drilling, and in processing of various materials for components of crushers, mills, and construction machinery (lining plates, hammers, jaws, cones).

Austenitic manganese steel has a yield strength between 50,000psi (345MPa) and 60,000psi (414MPa) [3]. Although stronger than low carbon steel, it is not as strong as medium carbon steel. It is, however, much tougher than medium carbon steel. Yielding in austenitic manganese steel signifies the onset of work-hardening and accompanying plastic deformation. The modulus of elasticity for austenitic manganese steel is 27106psi (186103MPa) and is somewhat below that of carbon steel, which is generally taken as 29106psi (200103MPa). The ultimate tensile strength of austenitic manganese steel varies but is generally taken as 140,000psi (965MPa). At this tensile strength, austenitic manganese steel displays elongation in the 35%40% range. The fatigue limit for manganese steel is about 39,000psi (269MPa). The ability of austenitic manganese to work-harden up to its ultimate tensile strength is its main feature. In this regard austenitic manganese has no equal. The range of work-hardening of austenitic manganese from yield to ultimate tensile is approximately 200%.

When subjected to impact loads Hadfield steel work-hardens considerably while exhibiting superior toughness. However, due to its low yield strength, large deformation may occur and lead to failure before the work-hardening sets in [11]. This phenomenon is detrimental when it comes to some applications, such as rock crushing [12]. Work-hardening behavior of Hadfield steel has been attributed to dynamic strain aging [13]. The hardening or strengthening mechanism has its origin in the interactions between dislocations and the high concentration of interstitial atoms also known as the CottrellBilby interaction. Thus, the wear properties of Hadfield steel are related to its microstructure, which in turn is dependent on the heat-treatment process and chemical composition of the alloy. According to Haakonsen [14], work-hardening is influenced by such parameters as alloy chemistry, temperature, and strain rate.

Carbon content affects the yield strength of AMS. Carbon levels below 1% cause yield strengths to decrease. The optimum carbon content has been found to be between 1% and 1.2%. Above 1.2% carbides precipitate and segregate to grain boundaries, resulting in compromised strength and ductility particularly in heavy sections [15]. Other alloying elements, such as chromium, will increase the yield strength, but decrease ductility. Silicon is generally added as a deoxidizer. Carbon contents above 1.4% are not generally used as the carbon segregates to the grain boundaries as carbides and is detrimental to both strength and ductility [15].

Manganese has very little effect on the yield strength of austenitic manganese steel, but does affect both the ultimate tensile strength and ductility. Maximum tensile strengths are attained with 12%13% manganese contents [16]. Although acceptable mechanical properties can be achieved up to 20% manganese content, there is no economic advantage in using manganese contents greater than 13%. Manganese acts as an austenitic stabilizer and delays isothermal transformation. For example, carbon steel containing 1% manganese begins isothermal transformation about 15s after quenching to 371C, whereas steel containing 12% manganese begins isothermal transformation about 48h after quenching to 371C [15].

Austenitic manganese steel in as-cast condition is characterized by an austenitic microstructure with precipitates of alloyed cementite and the triple phosphorus eutectic of an Fe-(Fe,Mn)3C-(Fe,Mn)3P type [17], which appears when the phosphorus content exceeds 0.04% [18]. It also contains nonmetallic inclusions, such as oxides, sulfides, and nitrides. This type of microstructure is unfavorable due to the presence of the (Fe, Mn)xCy carbides spread along the grain boundaries [19]. However, in solution-treated conditions austenitic manganese steel structure is essentially austenitic because carbon is in austenite solution [19]. The practical limit of carbon in solution is about 1.2%. Thereafter, excess carbon precipitation to the grain boundaries results, especially in heavier sections [20].

Austenitic manganese steel in the as-cast condition is too brittle for normal use. As section thickness increases, the cooling rate within the molds decreases. This decreased cooling rate results in increased embrittlement due to carbon precipitation. In as-cast castings, the tensile strength ranges from approximately 50,000psi. (345MPa) to 70,000psi (483MPa) and displays elongation values below 1%. Heat treatment is used to strengthen and increase the mechanical properties of austenitic manganese steel. The normal heat-treatment method consists of solution annealing and rapid quenching in a water bath.

Considering the mechanical properties, it is difficult to imagine that a casting made from Hadfield steel could suffer failure in service. However, cases like this do happen, especially in heavy-section elements and result in enormous losses of material and long downtimes. The reason for such failures is usually attributed to insufficient ductility, resulting from sensitivity of austenitic manganese steel to section size, heat treatment, and the rapidity and effectiveness of quenching [21]. Poor quench compounded by large section size results in an unstable, in-homogenous structure, subject to transformation to martensite under increased loading and strain rate. This article investigates the cause of incessant failure of locally produced crusher jaws from Hadfield steel.

According to the recent marketing research data conducted by the foundry an estimate of 15,000metrictons of this component is being consumed annually in the local market. This is valued at about $30million. From this market demand, the foundry plant can only supply about 5% valued at $1.5million. This is because the crusher jaws produced locally failed prematurely. Hence, this study aimed at investigating the causes of failure.

Annual wine exports in the European Union is around 21.9 billion (Eurostat) with France being the main wine exporting country followed by Italy and Spain. The wine production process (Fig. 9.1) can be divided into the following stages (Sections 9.2.1.19.2.1.4).

Grape crushers or crusher destemmers are initially used via light processing to avoid seed fracture. Sulfur dioxide is added to the mass to prevent oxidation. At this stage, grape stems are produced as one of the waste streams of the winery process. The mash is pressed in continuous, pneumatic, or vertical basket presses leading to the separation of the pomace (marc) from the must. Microbial growth is suppressed via sulfur dioxide addition.

The solids present in the must are removed before or after fermentation for white wine production. Fining is achieved by combined processes including filtration, centrifugation, flocculation, physicochemical treatment (e.g., activated carbon, gelatin, etc.,), and stabilization to prevent turbidity formation (e.g., the use of bentonite, cold stabilization techniques, etc.). Clarification leads to the separation of sediments via racking.

Wine production is carried out at temperatures lower than 20C for 610 weeks in stainless steel bioreactors or vats with or without yeast inoculation (most frequently Saccharomyces cerevisiae). At the end of fermentation, the wine is cooled (4C5C) and subsequently aged in barrels or wooden vats. The sediment that is produced during fermentation and aging is called wine lees and constitutes one of the waste streams produced by wineries. Current uses of wine lees include tartrate production and ethanol distillation. Lees could also be processed via rotary vacuum filtration for recycling of the liquid fraction and composting of the solid fraction.

Wine is cooled rapidly to facilitate the precipitation of tartrate crystals. Fining is applied for the separation of suspended particles using bentonite and gelatin. Filtration is subsequently applied to remove any insoluble compounds. The wine is finally transferred into bottles.

The main differences in the red wine production process are skin maceration duration, fermentation temperature, and unit operation sequence. Whole crushed grapes are most frequently used in red wine fermentation, which is carried out at 22C28C to facilitate the extraction of color and flavors. The remaining skins, seeds, and grape solids after fermentation are pressed to recover wine with the correct proportions of tannins and other compounds necessary for the final wine product.

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