Mechanical Engineering

How does a US landfill operate

What is a landfill

A landfill is a site specifically built to handle waste materials and is planned to occupy a large area. The landfill is officially classified as a disposal site and controlled through zoning and waste management laws. Such a site is created by using layers of compacted waste material, covering it with soil, then topped off with a layer of clay.

This article will look at a dumpster rental’s role in a landfill operation and how they can be used to help improve the process.

What Type of waste reaches a Landfill

A dumpster is the waste container that helps landfills operate in the US. The waste includes the garbage and the recyclable materials like paper, plastic, wood, and metals. The dumpster carries the trash to the landfill.

The destruction, consisting of the garbage unsuitable for recycling, is disposed of in the landfill, also called a garbage dump or the garbage site. The waste is collected from the home, offices, and industrial places.

The dumpsters and the waste bins delivered by the dumpster rental companies help the landfill operate. The waste is collected from the locations in the dumpsters provided by the dumpster rental companies, and the waste is disposed of in the landfill.

What happens to waste after being deposited in a landfill

Over time, buried waste breaks down into smaller pieces and mixes with the soil layers above it. This process is called leachate. Leachate is a mixture of rainwater, garbage, and other liquids that drain from waste and sewage.
Over time, the trash in landfills breaks down, and the size of the pieces becomes smaller. This allows juices to flow more quickly through the debris, turning the garbage into sludge.

Once the trash has decomposed, leachate can flow out of the landfill and into the ground below. As the leachate flows through the soil, it leaves salts and other chemicals behind. This can be harmful to plants and animals that live on the ground.

How does a US landfill works

There are many ways to dispose of your unwanted junk. One of the most accessible and affordable ways to do this is to rent a dumpster. A dumpster rental is an excellent way to get rid of large amounts of trash when your home or business is undergoing a major clean up. There are various dumpster sizes available depending on the user’s needs.

If you are not sure what a dumpster rental is, it is a large metal container that can be filled with all of your trash. The container is then sealed, and the waste is hauled away to a landfill.

How dumpster rental is needed in the operation of the landfill

Dumpster rentals are also needed in the operation of the landfill. They are used for the collection of debris on the site. Dumpster rental companies help collect garbage that can be easily disposed of.

Waste disposal is a task that is often taken for granted. We are often so used to our daily routines that we forget the amount of waste we generate daily. We pay no mind to the fact that someone has to collect the waste and ensure it is disposed of properly.

And while most people have no issues with this, they would be surprised to learn that there is more to waste disposal than they could ever imagine. Not only does it require a lot of human resources, but it also requires a lot of machinery. Garbage trucks are a sight that we are used to seeing in every neighborhood.

What are the plans for US landfills

A dumpster rental is the most common way to remove waste materials. It is more cost-effective, environment-friendly, and efficient, and it is a non-hazardous way of waste management. A container is attached to the vehicle and filled with various waste materials, and the container is then taken to a landfill site and disposed of.

In the United States, there are over 3,000 landfills that accept trash. Most landfills are lined with concrete, plastic, clay, or other waterproof material to protect groundwater. The liner also minimizes leachate, the liquid seeping down through the different waste materials.

Renting a dumpster is relatively more straightforward and faster than you may expect. If you have any queries about hiring a dumpster for your next project, please don’t hesitate to contact the nearest dumpster rental company. Allow them to assist you in locating the ideal solution for your undertaking!

If you are aware of the conditions of landfills, you will be more inclined to think twice before discarding waste. With the help of a dumpster rental, you can be sure that you will have efficient and waste-free services.

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The Power Of Mechanical Engineering

Mechanical engineers are often overlooked when it comes to fame and fortune. But their importance to the world is far greater than you might think.

Pretty much every industry uses machines and designs that wouldn’t have been possible without mechanical engineering. Even the enormous growth of cloud infrastructure wouldn’t have been possible with the advancements in cooling technology that were developed by mechanical engineers.

Mechanical Engineering In Renewable Energy

Mechanical, electrical, chemical, systems, and other sorts of engineers all contribute to the advancement of renewable energy infrastructure in the energy sector, which, like most modern fields of technology, is very multidisciplinary.

Every stage of renewables development and distribution can be handled by mechanical engineers. In order to lower costs of renewable energy infrastructure, mechanical engineers play a crucial role in discovering strategies to reduce the cost of silicon for solar panels and inventing more efficient ways to construct wind farms. Engineers in renewable power have a wide range of responsibilities, but these are some of the more important ones:

Improve the current renewable energy technologies in order to reduce the cost of constructing the necessary infrastructure.

Integration of various renewable energy technologies into a single system

Investigate various materials and their interactions in order to build new systems, methods, and infrastructure for the generation and distribution of energy in renewable sources.

Assessing a company’s sustainability goals, such as defining technology requirements, costs, and other aspects of investment and construction of renewable energy infrastructure, is an important part of providing advice on renewable – energy projects.

Design and optimise renewable energy equipment and services with the help of teams of engineers.

It is important to educate non-technical stakeholders such as business leaders and legislators about the viability of diverse renewable energy sourcing and distribution models.

Mechanical engineers provide various contributions to the renewable energy sector by research & development, addressing the problems like how to safely store energy for extended periods of time and how to enhance the design for equipment ranging form cooling systems to wind generators.

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Free Autocad Exercises From Beginner To Advanced


myCADsite provides online AutoCAD tutorials both for new and expert users with really no registration needed. Tutorials are grouped into 4 levels: beginning AutoCAD, basic AutoCAD, intro to 3D & advanced topics. Each set of lectures is followed with a quiz to check your knowledge. You’ll also discover example CAD files and movies to accompany these HTML AutoCAD courses. To stay current on news & tutorials as they’re published, you may follow myCADsite on Twitter or Facebook.


Cadalyst delivers a vast assortment of AutoCAD & other CAD software lessons, tips and training tools. They have a comprehensive CAD tips gallery with films that teach students how to accomplish certain tasks in AutoCAD. For example, you may find videos illustrating three various ways to place a frame around the text in AutoCAD, how and where to scale something with a reference & so many more.


CADTutor provides free tutorials, tips & articles on AutoCAD, 3ds Max & linked software products. Not just that, but CADTutor can quickly help us connect with other CAD learners and experts their AutoCAD forums, that are a terrific free learning resource that can’t afford to miss out on.

Tutorial 45

This is just another should AutoCAD site have that on your list. Why? Tutorial 45 presents a compilation of free AutoCAD lessons containing practise exercises, listings of AutoCAD functions, 3D projects & easy to follow what articles. It includes all the basics users need!

Ellen Finkelstein

Ellen Finkelstein’s AutoCAD tips site is a big store of freeware AutoCAD tips, techniques & lessons arranged into categories which make it easy to access this extensive AutoCAD resource. Sift through the amount of categories that include: sketching, editing, text & dimensions, 3D, plotting & presentation, troubleshooting, AutoCAD customisation, and layers. With amount of resources accessible, you’re likely to find the aid you need.

AutoCAD Tutorial From Computer Aided Guide

Computer Aided Guide is basically a blog from all things CAD. Here you’ll discover all AutoCAD articles grouped into a comprehensive overview that provides for a nice free AutoCAD instructional resource that can bookmark.

The CAD Setter Out

The CAD Setter Out is the another site with all AutoCAD content organised in the AutoCAD tutorial category. To help readers & learners discover the specific AutoCAD tutorial they needed, the AutoCAD posts are further split down using post tags as AutoCAD creation, AutoCAD Edit, AutoCAD Document, AutoCAD Productivity,& AutoCAD Customization. provides a series of free AutoCAD courses, tips & techniques, and articles. The resources can stop there. You can find more free resources including such AutoCAD blocks, references, and more.


CadOasis offers various free AutoCAD tutorials especially designed to bring AutoCAD features to CAD users. So if you’re trying to gain a good insight of the essential on AutoCAD operations, here is the place to check out.

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Artificial Leaf Solar Power – How Does It Work?

For you to better understand how artificial leaf solar power works, you must first understand the concept of photosynthesis. Therefore, what is photosynthesis?

Photosynthesis is a process whereby an organism uses the power of sunlight to produce sugar. Plants, bacteria, and some single-celled organisms use photosynthesis to survive. In other words, these organisms use cellular respiration to convert sunlight into ATP (Adenosine Tri-Phosphate) ‘fuel’ to support a specific function. For example, plants use photosynthesis to create the green pigment chlorophyll.

As you probably know, chlorophyll is important as it plays a role in removing CO2 (carbon dioxide) from the air and release oxygen. ATP is an energy that is stored in living systems and consists of Nucleotide and three groups of Phosphate.

Why Is Understanding Photosynthesis Important In This Topic? 

Because nearly all living things depend on the energy produced from photosynthesis for nourishment, scientists wanted to understand this process and how we (human beings) can harness the potential power of sunlight.

After a lot of research, trial and error, and testing, solar cells were invented. These solar cells have the potential of converting sunlight into electric current.

Solar Cell Topic Overview 

Solar cells are also known as Photo Voltaic Cells. They are made from a semiconducting material, often silicon. When the semiconducting material is hit with light, it absorbs it using photons. The absorbed energy knocks electrons out of the silicon, which allows them to flow.

If semiconducting material like silicon is mixed together with other impurities such as boron or phosphorus, an electrical field. This electrical field acts like a diode where it only allows electrical current to flow in one direction and hence the production of electricity.

To know more on this topic, read more on: – Repeated Mechanical Stress creates stronger Nano Composites | Calculate High Cycle Fatigue | Nano Composite Material

The Limitations Of Solar Cells 

A solar cell can only achieve efficiencies of about 10%. Furthermore, they are expensive to manufacture. With this information, it is very clear that its major drawback is inefficiency. Besides, it is almost impossible to avoid inefficiency with silicon cells. That is because it demands an accurate photon or light band gap energy to allow electrons to flow. If the light has a low energy band gap, then it will pass through. If the energy band gap is high than the desired energy, then the extra energy will be wasted as heat.

Why Artificial Leaf

The artificial leaf comes with a mixture of photosynthesis, conventional solar cells, and hydrogen fuel cell.

Solar power with artificial leaf combines the available solar cell, with affordable catalysts made of Cobalt, and Nickle, which splits water into hydrogen and oxygen. The hydrogen is stored and used as an energy source.

Collecting and storing the energy from the sun as hydrogen fuel is the key to overcome the limits of the solar cell. It produces current while the sun is shining but also demands to be stored somewhere for night use or during cloudy weather. The energy can be stored in batteries, but we all know how limited this can be. Therefore, storing the energy as hydrogen may be the answer for producing continuous energy.

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All About Pressure Thermoforming

Pressure Forming 

Pressure forming helps produce injection-mold-quality high-definition plastic components, housing, containers, and without the high cost and tooling. Positive pressure is used to force the heated plastic parts into the mold cavity in the process. The method is known as Blow Forming or Pressure Thermoforming.

Pressure Forming Working Operation 

Pressure forming is a highly versatile method that uses air pressure from 20 to 150 psi to force the heated sheet of plastic into the temperature-controlled mold cavity. The mold consists of vent holes so that the trapped air can escape. The final part features tight radii, intricate contours, and sharp definition. In fact, accurate details and textures are usually built right into the tooling. The method helps produce aesthetically pleasing plastic parts of varying sizes at a much lower cost. The method also helps better monitor sheet and tool temperatures and control material shrinkage.

Types Of Molding Operation 

  • Positive Mold
  • Negative Mold

The positive mold has a convex shape, while the negative mold has concave cavities.

Pressure Forming VS Thermo Forming 

Pressure forming is quite cost-effective when producing small items. This is the basic advantage of pressure forming compared to thermoforming. In fact, the cost of the mold in thermoforming is quite high. Hence, lower quantity precision jobs are best suited for pressure forming.


Pressure forming is mostly used to create a wide range of plastic products used in the food industry, including food trays. Some of the other products include internal parts, covers, blisters, bezels, housings, bases, and spare parts used in business machines, computers, peripherals, electronics, bio-medical applications, and instruments.


Pressure forming helps achieve many features beyond vacuum forming capabilities – such as ribs, louvers, crisp details, logos, and recessed areas. The method is great for small and medium-sized production processes that don’t justify the cost of molding dies. On the other hand, the aluminum tooling used in the method has an extended lifecycle due to the non-abrasive process. Hence, it helps save a great deal of money in your business. Pressure forming tools are inexpensive compared to injection tools. It costs less than 10% of the cost of an injection tool. Tooling lead time is also saved by at least 25%. Sheet gauges between .020″ – .500″ can be pressure formed.

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Autocad Freestyle 2D Explanation and Exercises

AutoCAD Freestyle: What Is It? 

AutoCAD Freestyle was built from the AutoCAD platform. It’s also compatible with the file format of AutoCAD DWG. You can create a file in AutoCAD or even AutoCAD LT and then open it in AutoCAD Freestyle. You can also add notes, sketches, and drawing enhancements. You can also save round-trip or finishing workflow in conjunction with other applications based on DWG.

While AutoCAD necessitates a considerable amount of training, nearly anyone is able to begin AutoCAD Freestyle immediately, given the integrated learning tools it comes with.

When you open a DWG file from other applications in AutoCAD Freestyle, you can’t edit the original objects. That means that all text and geometry are locked into their layers.

AutoCAD Freestyle can only open a single paper pace layout each time. When DWG files that are created using other applications have more than one paper space layout, then users can choose a specific layout to utilize.

DWG files that are created using other applications have a 3D view that might be a bit limited in terms of functionality if opened and viewed using AutoCAD Freestyle.

All fill elements, geometry, and text that get added to files through AutoCAD Freestyle get automatically put onto new layers specific to AutoCAD.

If you are a user of AutoCAD or other software applications based on DWG, and you intend to send DWG files to users not accustomed to DWG drawings, then it’s smart to make a DWG file using a single viewport with a paper space layout.

In the application, there isn’t a way to add blocks or new symbols to the library. However, you can do it if you manually edit the AcTpCatalogacadfs.atc ToolPalette file. There is support for dynamic blocks.

AutoCAD Freestyle usually saves to the 2007 AutoCAD DWG file format, but it has the ability to open 2010 DWG formatted files. It appears that the first release was based on 2010 AutoCAD, given the interval version number 18.0, rather than the 2011 AutoCAD 18.1.

Dedicated Sets Of Tools

There are intelligent objects for architectural, engineering, electrical design and more that are included in AutoCAD’s industry-specific capabilities.

  • Automate the creation of floor plans, divisions, and elevations.
  • Quickly create plumbing, ductwork, and electrical circuits by using part libraries.
  • Generate annotations, layers, timetables and tables automatically.
  • For accurate enforcement of industry standards, use a rules-based workflow

This page includes some instances of AutoCAD’s functionality. In order to create these fantastical architectural illustrations, AutoCAD is used. If you’ve never used AutoCAD before, here’s a listing of 50 Commands That Should Know to get you started.

Working On The Go

AutoCAD is available on nearly any device, according to Autodesk, making it easy to maintain a streamlined workflow. Using AutoCAD phone app or the AutoCAD web app, drawings may be created, viewed, altered, and annotated while on the go.

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The Benefits Of Reverse Engineering And How To Do It

How Is Reverse Engineering Defined? 

Reverse engineering is making a product or a component of an item without any blueprints, models, or documentation. It allows you to copy a product or component by recording the item’s physical aspects such as dimensions, properties, and various features.

In what situations would you need to reverse engineer? Here are some examples:

  • The product or component is no longer produced by the original company that manufactured it
  • A client needs an item, but the original maker of the item does not exist anymore
  • There is a design, but there are insufficient details to make a copy of the product, or the original design documents don’t exist anymore.
  • You have a product; you want to improve the good features and remove the bad features
  • You want to improve old and inefficient manufacturing processes
  • You have a competitor’s product, and you want to evaluate its good and bad components. You want to know what the benchmarks are so you can exceed them to gain a competitive advantage in the market
  • You want to evaluate a product to see how you can improve performance
  • You have a CAD model, but it does not have enough information to support manufacturing or changes
  • You need parts, but they are not available from the original supplier, or the supplier is charging an inflated price that you are not willing to pay

In reverse engineering, you first determine the components in your product and how they work together. Then, you make a blueprint that represents this product. Finally, you use your blueprint to create a copy of this product.

Before we dive into some of the best reverse engineering techniques, there are some important aspects to keep in mind.

  • To justify the commitment of time, money, and resources of the reverse engineering project, you should do analyses of the product’s life cycle and the cost versus benefits.
  • It is worthwhile if you plan to produce a high number of these items and achieve cost-effectiveness. The exception is that if the product you need to make is absolutely essential to a system, it can justify a higher expenditure.

Reverse Engineering Of A Product That Requires Computer Aided Design (CAD) 

By using computed tomography or a laser scanner, you can use CAD to create parametric surface patches by getting 3-D positional data, then reverse engineer that into surface points that come together to make the shape.

Reverse engineering software allows you to create a quality poly-mesh. The non-uniform rational B-spline (NURBS) curves and surfaces are fed into the CAD applications for more detailed rendering and analysis. Paths to cut are generated for the computer-aided manufacturing stage of the process where the physical product is produced.

Services include scanning with a laser, which can be with or without contact, a comparison analyzing how the CAD model deviates from the actual part, and inspects the dimensions. Reverse engineering includes the hardware for scanning and digitization, CAD software for design, and the reverse engineering plug-in that incorporates CAD.

It’s important to keep in mind that some design information is not directly available in the end product. This includes things like processes to create the materials or tolerances for molds.

CAD computer software You Can Use For Your Reverse Engineering Efforts 

  • RapidformXO Redesign: this enables you to use physical parts to efficiently make parametric CAD models. Any user who is familiar with CAD will find this intuitive to use.
  • Geomagic Studio: this translates polygon meshes and 3-dimensional scan data into 3D models. Great for making fast prototypes, designing and analyzing the product.
  • RevWorks: A great tool for improving productivity and efficiency. This links your 3D scanning system or CMM (coordinate measuring machine) to SolidWorks. Great for any reverse engineering process that integrates CAD.
  • DezignWorks: The standard for SolidWorks. This allows you to make highly detailed 2-dimensional and 3-dimensional shapes with the coordinate measuring machine systems from Faro, Romer, Baces, and MicroScribe.
  • Rhinoceros NURBS Modeling for Windows: this allows you to design, edit, and render NURBS surfaces, curves, and solids on the Windows platform. It supports all 3-dimensional scanners and portable CMMs.

Software used for inspection includes: 

  • MobiGage: This can be used on your iPod Touch or iPhone. It handles data collection from linking a MobiBox Silver interface to MicroScribes. This is done wirelessly.
  • Delcam’s PowerINSPECT: This is the industry leader in providing a comprehensive solution to CAD-based inspection.
  • RapidformXO/Verifier: Perfect tool for parts inspection using a 3D scanner.
  • Geomagic Qualify: this allows you to compare a digital model to a physical part efficiently and accurately for inspection and evaluation of product quality

When Reverse Engineering Would Be Used:

Reverse engineering is often used in a wide range of industries, including automotive, entertainment, consumer electronics, and software engineering, just to name a few. For instance, when a company comes out with a new product in the manufacturing industry, a competing company might get the product and take it apart to study the components, features, and operation.

In the chemical industry, a company might reverse engineer a competitor’s product to challenge a patent. In the software industry, existing source code is reverse engineered to create better source code. In civil engineering, an old, proven bridge design is reverse engineered to make it even more stable.

Sometimes, designers create a rough shape of their ideas by using materials like wood, plaster, foam rubber, or clay. However, the detailed design is done by CAD in order to make the actual part. With that said, it is not absolute that the model created in CAD will be an accurate representation to the physical model. This problem is solved with reverse engineering in a part-to-CAD process because you start with the physical model first. Then this data becomes the source for the CAD model.

Reverse engineering can also be used when you want to shorten the time to develop a product. The faster you can get a product from design to market in the current marketplace, the better competitive position you will be in.

Companies embrace rapid product development, or RPD, a technology that supports designers and manufacturers to cut down development lead times. This applies to all manufacturing industries. Reverse engineering allows you to take a physical product, translate it into a digital format, change the model, and then output the design to make a fast prototype or speed up manufacturing.

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How Tandem Windshield Wipers With Electronic Control Work

The same simple design has been used for windshield wipers for decades. And while this is clearly a reliable and effective design, modern technology has enabled us to do better.
Electronic motor control is now so performant that it can be used to replace many mechanical solutions. This leads to more efficient mechanisms, lower part counts, and better reliability.

Conventional Windshield Wipers

One rotation direction is used with conventional wiper drives, and the wiper direction is reversed when the crank switches sides.

The new wipers’ mechanical components require less space to work because they employ electronically controlled motors that can reverse the rotation direction at the wiper’s turning point.

No matter how hard or fast the wind is blowing or how much friction is present, the window area is always visible due to the electronic controller.

The area that is swept by the wipers can actually be increased by lowering the tolerance distance and altering the wiping angle. Objects such as snow that would normally provide obstructions can be detected by the controller.

The reversing points provide a way for the controller to avoid blocking by making the wipers sweep less of the window. In order to make the system as quiet as possible, before a reversal happens, the motor is slowed down.

When paired with a rain sensor, the electronic speed controller works quite well in operating continuously at a variable speed while keeping in mind how much water has gathered on the windshield.

Two motor wiper systems can also be used when there is an electronically controlled wiper motor. The controller works in sync with each wiper arm, which both have a drive unit of their own.

Advantages Over Conventional Wipers 

  • Connecting rods aren’t needed for the system to work.
  • Less space is needed.
  • It has lighter weight.

Features & Benefits 

The wipers can be put in place under the bonnet’s trailing edge when they’re turned off. This is called an extended parking position, and it’s a useful extra feature for wipers. Vehicles have better aerodynamics with the wipers parked in this position because of a reduction in driving noise. Drivers can even see more with the wipers parked, which lowers the risk of accidents caused by vehicle collisions or drivers hitting a pedestrian.

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How Does A Bucket Elevator Work?

Bucket elevators are conveyors that carry bulk materials along an inclined or vertical path. The bucket elevators for vertical and mechanical transportation of goods has become an important link in production processes for several industrial sectors.

The standard bucket elevator is made up of:

  • An endless belt
  • Chains or a chain that the bucket attaches to
  • Necessary discharging and loading terminal machinery
  • A drive arrangement
  • Supporting casing or frame

The Layout Of A Bucket Elevator – Bucket Elevator Parts 

Materials are first fed into a type of inlet hopper. The cups or buckets dig into materials, which are then conveyed up and over a pulley or head sprocket, followed by throwing the materials out of a discharge throat. The empty buckets then continue this cycle by returning back to a boot.

The Industrial Bucket Elevators come in various sizes, weights, and shapes, using either continuous buckets or centrifugal buckets. The belt is usually made from metal, plastic, rubber, or natural fibers.

The Centrifugal Bucket Elevators are more commonly used for conveying free-flowing materials. These buckets operate at high speed to throw materials out of the buckets inside a discharge throat using centrifugal force.

Continuous Bucket Elevators operate at a slower speed and include buckets that are evenly spaced. The buckets’ even placement lets gravity successfully discharge loads onto an inverted-front of a preceding bucket. These buckets will then guide the materials into a discharge throat along the elevator’s descending side. This minimizes product damage or is used to handle fluffy, light materials whereby aeration of the materials needs to be avoided.

Bucket Elevator Chain And Belt Type 

The motion of a chain or belt is un-directional. Bucket elevators are simple yet extremely reliable devices for lifting bulk materials. Bucket elevators share a few benefits, which include the simplicity of fabrication and design, the initial investment is low, and they require minimal floor space.

Bucket Elevator Types 

In most cases, bucket elevators are grouped according to the discharge mode and the bucket “spacing.” These include:

  • Centrifugal discharge elevators
  • Positive discharge elevators
  • Continous or gravity discharge elevators

Bucket Elevator Components

The main parts of a bucket elevator include:

  • Buckets
  • Boot arrangement
  • Carrying medium
  • Casings
  • Head arrangement

Bucket Elevator Round Link Chain 


The types of materials that are typically conveyed by a bucket elevator include:

  • Foundry sand
  • Limestone crushed to 25 to 30mm sizes
  • Coal
  • Sugar
  • Coke
  • Chemicals
  • Animal feed
  • Phosphate rock
  • Friable
  • Cement mill clinker
  • Snacks
  • Candy
  • Fragile materials
  • Rice
  • Coffee
  • Seed
  • Detergents
  • Plastic granules
  • Soaps

Limitations Of Round Link Chain Bucket Elevators

The limitations of these systems typically include the following:

  • The lump size must be under 100mm
  • The materials should have an ambient temperature or, in some cases, slightly above
  • The materials cannot be excessively abrasive or corrosive

The Benefits Of The Belt System Over The Chain System 

The traction elements are either an endless chain or endless belt, but the belt systems are preferable for certain conditions due to these reasons:

  • Quieter operation
  • Higher speeds become possible
  • Offers improved abrasive resistance for materials such as coke or sand
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Casting Testing And Inspection

Many different methods have been developed for inspecting castings for any defects that might arise during the production process. These inspections can either be finished product inspections or in-process inspections.

In-process inspections are conducted before too many castings are produced to detect any flaws that might have developed during the process. That allows for corrective measures to be taken to remove the defect from the remaining units. With finished product inspections, the castings are inspected after all of them are finished to ensure that the product meets the customer’s requirements.

Defective castings can either be salvaged or totally rejected and re-melted for the materials contained in them, depending on the defect’s extent and nature. These methods can also be divided into non-destructive and destructive categories depending on the extent of the damage that is sustained by the casting during the inspection process. Usually, destructive methods are related to breaking or sawing off parts of the castings in places where it is suspected there are internal defects or voids. During strength tests, castings can also become damaged. The disadvantage to destructive tests is that saw cus might miss the flaw, or a sample might not represent the whole lot. Due to these reasons, non-destructive tests are relied on more often than destructive tests.

The following are some of the most prominent non-destructive methods that are used:

Visual Inspection

This involves using the naked eye or a microscope or magnifying glass to inspect the casting’s surface. This method can only detect surface defects like mismatches, external cracks, swells, fusion, and blowholes. Some form of visual inspection is done on almost all castings.

Dimensional Inspection

This type of inspection is conducted to ensure that the casings have all of the necessary overall dimensions along with machining allowances. It might be necessary to break part of the casting to measure the inner dimensions.

Sound Test

This is a type of rough test used to indicate a discontinuity or flaw in a casting. It involves suspending the casing from an appropriate type of support that is free of obstructions. Then various areas on the surface of the casting are tapped using a small hammer. If there is any change in tone, that is an indication that there is a flaw. This method cannot indicate the extent or precise location of the flaw.

Impact Test

A hammer of a certain weight strikes or falls on the casting on this test. A defective casing will fail due to the impact of the hammer’s blow. However, this is a very unreliable and crude inspection method.

Pressure Test

This type of test is conducted on castings that need to be leak-proof. The castings openings are all closed, and a fluid or gas under pressure is then introduced into them. This pressure will cause castings with porosity. To detect leakage, a casting can be submerged in a water tank, or a soap film can be used to apply the pressure if compressed air is used. Visual inspection can detect leakage if a liquid is used to apply pressure.


Radiography uses gamma rays or X-rays that penetrate through the casting to provide a shadow image on the photographic film placed in the back of the casting. The rays have very short wavelengths of 0.001 to 40 Angstrom units, to around 3 Angstrom units on gamma-rays in comparison to around 5500 Angstrom units n the middle of the visible spectrum.

These waves being able to penetrate through metal will also depend on how dense the metal is. They are to penetrate more easily in areas with less meal than those where there is more meal, leading to a shadow picture forming on the film. These pictures make it easy to identify any defects the casting might have. Gamma rays have shorter wavelengths which means they can penetrate through metal better and are used more frequently as a result.

Magnetic Particle Testing

This type of test is used to detect cracks in metals such as steel and cast iron which may be magnetized. The casting is magnetized to conduct the test. The fine particles of steel or iron are spread on the surface. If there is a void or crack in the casting, it will result in the magnetic field being interrupted, and magnetic flux will leak where the crack is.

The particles of steel or iron that are spread onto the surface of the casting are held by the leaking flux and provide a visual indication of the extent and nature of the crack. Voids or very small cracks close to the surface might not be detected by radioactive, but this method can easily reveal them.

Penetrant Testing

This type of test is used to detect very small surface cracks. Compared to the magnetic particle test, it has the advantage of being able to use it with any material. Whatever parts are being tests are either covered with or dipped into a penetrant testing looking with good penetrating and wetting abilities. Capillary action is used to draw the liquid into the voids or cracks.

Once the penetrant is applied to the surface being tested, the excess penetrant gets wiped off of the surface and then dried. Next, a developer is applied. The developer helps to draw the penetrant out so that it will be visible on the surface. These penetrant liquids frequently contain materials that fluoresce under an ultraviolet die or light to indicate they are present.

Ultrasonic Testing

This type of testing is used for detecting defects such as porosity, voids, or cracks within the casting’s interior. Transmission and reflection of high-frequency sound waves are used b this method. It produces ultrasonic sound waves that are much higher compared to the audible range and are passed through the casting.

A cathode-ray oscilloscope records the time interval between the reflected ray and the transmitted ray. Any void or crack in the casting will rest in some sound or reflection from the crack and appear as a pip in between the two pips that represent that casting’s thickness. It is easy to calculate the depth of the crack on the crack on the casting surface by the distance in between the pips.

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