Screening & Separation
Screening equipment is used to sort bulk materials with great attention to detail so that only the right particles end up in the final bulk stream. Unlike separating equipment, screeners sift materials mechanically. There are many different types of screening equipment that can be used in a bulk system.
The piece of equipment that is used depends on the industry and type of material being processed. Sometimes solids must be separated from solids, and in other applications liquids are removed from solids or vice-versa. While there is a long list of screening equipment, below are a couple of the most popular and common types among bulk material handlers.
Vibratory screeners are likely the most common piece of screening equipment in bulk applications. As the material moves across the screen, the machine creates vibrations that shake out small particles and remove clumps from the material. This is one of the most effective and efficient ways to separate materials by size. The size of the particles being sifted out can be determined by the pattern and shape of the metal screen and the rate of the vibrations. Vibratory screeners come in many different sizes and can process large volumes of material in certain applications. A linear vibrator is used to gently process dry goods by sifting them on a fine screen at a low frequency and in a stationary horizontal position.
High Frequency Screens
High frequency screens use intense vibrations to separate fine particles in applications like mineral processing. An electromagnetic vibrator connected to the surface of the screen controls the intensity of the vibrations as materials are introduced to the screen from a conveyor. High frequency screens can be used as a secondary screening measure to remove fine particles before or after the primary screening process.
While high frequency screens and vibratory screeners are the most likely to be found in a bulk material handling system, other types of screeners that may be used include: rod decks, disc screeners and star screeners. Each of these is best suited to sort larger individual objects rather than the fine particles or granules that are typically processed in most bulk facilities. In recycling and waste recovery centers, disc and star screeners are usually used to separate recyclable materials based on their size.
Screening equipment in bulk applications allows bulk material handling facilities to refine and purify their materials before they are packaged or shipped to distribution centers. With the right piece of screening equipment in a system, bulk handlers can process material in large volumes without compromising the quality of their product or allowing it to be contaminated by unwanted debris. Applications for screeners vary greatly and can include agricultural products, pet food, bulk baking ingredients, pharmaceutical batches and more. Screening equipment is easy to maintain and designed to operate continuously for high volume production in a busy bulk material handling facility. Some machines are even self-cleaning, meaning that they remove debris from the mechanism without the need for manual cleaning between production runs.
When raw bulk materials are being processed, sometimes it is important to separate the materials based on quality or particle size. In some applications, the final product must be 100% pure, or may only be of value when it had been refined. While this can be accomplished manually, it is much more efficient when separation equipment is used to sort bulk material. Some of the most common pieces of material separation equipment for bulk applications are listed and described below.
Magnetic separators are important in the mining industry where they can be use to separate ferrous and non-ferrous metals. A magnetic separator can prevent harmful bits of metal from entering machinery further down the line, and they can remove impure or unwanted materials from a stream. The magnets pull out the unwanted material as the bulk materials pass by on a conveyor. A permanent magnetic separator does not need any electric power to operate. These mechanisms can last for a long time without requiring maintenance or losing a significant amount of strength. More powerful industrial magnetic separators may use coils and direct currents to create a stronger magnetic field.
To make sure that volume measurements in a bulk handling system are accurate, an air separator is used. As bulk material passes through the chamber of an air separator, air or gases are removed from the material. Vacuum technology is commonly used to suck all of the air out of a confined space so that the only remaining substance is the bulk material itself. An air separator can easily be integrated into a pneumatic conveying system as either side of the unit can be connected to pipes or tubes.
Flotation separators use the principle of buoyancy to separate bulk materials. Water is added to a large tank, and the water’s density can be altered using certain additives that help to create the desired effect. Next, the material is added to the water. As a result, only materials with a density greater than that of the water will sink to the bottom of the tank as the rest remain floating at the surface. Mechanical arms scoop up the floating materials and move them along to the next part of the system. Floatation separation is an efficient way to separate minerals from other particles and debris. The debris that has fallen to the bottom of the tank can be ejected through a discharge hatch or periodically cleaned out of the tank from above.
Materials separation equipment is used to sort particles in bulk material handling systems in industries that range from agriculture to pharmaceuticals to food processing, mining and beyond. With machines that can separate high volumes at such a rapid rate, bulk material handlers in some industries are able to process more materials in a day than they could by way of manual labor in a week. Technological advancements like this are what help to make bulk material operations so large and efficient today and enhance the many possibilities of bulk handling.
A vibratory screener is a stationary or portable piece of equipment in a bulk material handling facility that removes unwanted materials from a batch using vibrations. Materials are moved over a screen and vibrated in such a way that only the desired particles fall through, while larger debris is caught by the screen. If there is unwanted liquid in the material, a sieve type vibratory screener is used to separate the solids from the liquid. Sometimes the waste is recycled after cleaning if it can be broken down into a useable form.
Vibratory screeners are not just used to separate materials; they are also important for classifying bulk materials by size. The larger or smaller materials that are removed may not necessarily be unwanted, they might just need to be classified and packaged differently. Plastic pellets can be sized and screened using a vibratory feeder during the handling process. Although there is a wide variety of vibratory screening machines available on the market, some unique handling applications require customized screeners. Specialized manufacturers offer custom-built vibratory screeners based on the dimensions and processing needs of your facility.
There are a number of considerations that need to be made when you are purchasing a piece of vibratory screening equipment, or when you are working with a team of engineers to design one. First, you need to determine what vibration frequency works best for the material that you will be handling. This can be determined by testing with a vibratory screener at various frequencies to find the optimal setting. You will also need to find out how large the screen should be and what size the reservoir needs to be. The reservoir holds material or feeds it into the next stage of the process. The size of the screen and the reservoir below it will depend on the scale of the bulk material operation. However, even in a large processing facility, the vibratory screener cannot be too large or it will not screen material as thoroughly.
Leading Screening & Separation Equipment Manufacturers
ERIEZ is a global manufacturer of an entire range of vibratory separators and related machinery. We serve all the process industries, including food, chemical, pharmaceutical, ceramics, glass, packaging, metalworking, minerals processing and others. We also offer feeding machines so that all of your needs can be met. Please contact our company for a quote today!
Internationally known, Carrier Vibrating Equipment specializes in manufacturing vibratory feeders and separators. We have been pioneers in process equipment technology for over 60 years. Our economical products are easily installed, offering minimum downtime and low maintenance. Our equipment serves industries such as chemical, glass, dairy, pharmaceutical and explosives.
At General Kinematics, we design and manufacture vibratory separators for applications in foundries, recycling mining, coal and food processing. We are always working on new, creative designs for our customers that are cost effective in pricing. We have the expertise and knowledge to respond to your objectives for efficient, dependable, products.