Industrial Conveyors Information
Industrial conveyors are horizontal, inclined, declined, or vertical machinery that transport bulk materials or discrete units from one place to another at a controlled rate.
There are two main conveyor technologies: bulk material and unit handling. There are also many different conveyor types. Belt conveyors are the most popular type of conveyor. Industrial conveyors differ in terms of features. Roller, live roller, belt and gravity conveyors are designed to allow the accumulation of materials. Industrial conveyors with magnets are used to move ferrous materials.
Types of Industrial Conveyors
Types of industrial conveyors include:
Air tables - Air tables are used when products must be rotated manually or positioned correctly. They are used with workstation operations and other activities that require quick, easy handling of products. Air tables can also be used when more than two conveyor lines converge and packages must be transferred from one line to another.
Ball transfer tables - Ball transfer tables are used when products are required to be manually rotated or correctly positioned, such as a workstation or other similar operation that requires quick, easy handling of the product. They can also be used when more than two conveyor lines converge and packages must be transferred from one line to another.
Anti-static conveyors - Anti-static conveyors are made of materials that do not allow the build up or storage of an electrical field.
Belt conveyors - Belt conveyors are made of an endless, fabric-covered belt that traverses between two or more pulleys and is supported by idler rolls at intermediate points. Belt conveyors can move materials ranging from fine powders to large, lumpy stones at belt speeds ranging from 20 to 300 m/min.
Bucket conveyors - Bucket conveyors consist of a bucket elevator and an endless belt or chain with a series of attached buckets. The buckets are filled, lifted vertically to a head pulley or sprocket, and dumped. The buckets are then returned to a tail pulley or sprocket at the bottom. Bucket elevators are not self-feeding. To avoid overfilling the buckets and damaging the machinery, bucket elevators should be fed at a controlled rate. Typically, bucket elevators are placed where the chain or belt path is vertical or steeply-inclined in a single plane. Special, chain-supported bucket systems that can travel in two and three planes are also available. There are four broad categories of bucket elevators:
- Internal discharge
The most commonly used types are centrifugal elevators and continuous discharge elevators. Positive discharge elevators and internal discharge elevators are used for special applications.
Cart-on-track conveyors - Cart-on-track conveyors are used to pull a cart along a track. Basic components include a rotating tube, track, and cart. The rotating tube, which is similar to a screw, transports the cart. The drive wheel is connected to the cart, which rests on the tube. Varying the angle of contact between the drive wheel and the tube can control the speed. Because they are independently-controlled, multiple carts can be located on the tube. These carts can accumulate on the tube and remain stationary when drive wheel is parallel to the tube.
Chain conveyors - There are five basic types of chain conveyors: push-bar conveyors, twin chains conveyors, sliding chain conveyors, heavy-duty plates for assembly conveyors, and apron or slat conveyors. These different types have two distinct functions:
- Support the product being conveyed.
- Carry the actuating elements between the two chains.
Chain conveyors operate overhead or are set on the floor. In a sliding chain conveyor, either plain links or links with special attachments such as lugs are made up into the conveyors to handle cases, cans, pipes, or other similar products. Slats or apron conveyors are fitted with slats of wood or metal, either flat or in special shapes between two power chains. The slats can handle heavier objects such as barrels, drums, or crates. Because of the cleats, these conveyors can carry articles up steep inclines. Push-bar conveyors are a variation of the slat type. In this conveyor, two endless chains are cross-connected at intervals by pusher bars that propel the load along a stationary bed or trough of the conveyor.
Chute conveyors - Chute conveyors are a less expensive way to move materials with a conveyor. Often, chute conveyors are used to link two powered conveyors together, and for accumulation in shipping areas. Spiral chutes are used to convey items from floor to floor without using much space. The main limitation of chute conveyors is the lack of control over the items being conveyed. These items can become wedged in the conveyor and cause blockage.
Cleated conveyors - Cleated conveyors are designed to transport and control material over an inclined or horizontal plane.
Drag conveyors - Drag conveyors (drag chain conveyors) pull or drag material through a tube or U-shaped trough. Types include tubular, round bottom, flat bottom, and v-groove drag conveyors. Drag conveyors can be installed in a vertical, horizontal, or inclined position. The design of drag conveyors aids in self-clean outs and allows only negligible product degradation.
Flexible screw conveyors - With flexible screw conveyors, the rotating screw is the only moving part that comes into contact with the material being moved. The intake side of the conveyor does not contain seals or internal bearings, which greatly reduces the need for maintenance. The flexible screw can operate in a flexible or rigid tube; however, the flexible screw enables the conveyor to adjust to slight curves or moderate bends in the flow path when operated inside a flexible tube.
Free and power conveyors - Free and power conveyors are similar to trolley conveyors. They contain specifically spaced carriers that are transported by an overhead chain. Free and power conveyors derive their name from their design. They use one powered track and one non-powered track. The carriers are suspended on the non-powered or free track, and the two tracks are connected by “dogs”. The dogs mate with similar connections on either track to pull the carriers along. The main benefit of free and power conveyors is the ability to disconnect some carriers so they can be accumulated or switched onto spurs.
Gravity conveyors - Gravity conveyors do not use an external power source to move materials or products. Typically, they are titled or used on an incline to facilitate the manual movement of materials or products.
Monorails - Monorails are self-powered vehicles that ride on an overhead track. They conserve floor space and provide a flexible means of transportation. Monorails consist of a single, overhead track (monorail), or a track network on which one or more carriers ride.
Pneumatic tube conveyors - Pneumatic tube conveyors are tube systems that use low-pressure air to push or pull a short, closed cylinder through a pipe between the origin and destination.
Pneumatic or vacuum conveyors - Conveyors use the flow of pressurized air or a vacuum to move bulk material from one location to another.
Roller conveyors - Roller conveyors may be a powered or non-powered. The non-powered conveyors are referred to as gravity conveyors by inclining the roller section. The powered roller conveyors are either belt or chained driven. The rollers are connected individually to the drive shaft. The roller conveyors are well suited for accumulating loads and merging and sorting materials. Because of the rollers, the materials being moved on these conveyors must have a rigid riding surface.
Sanitary conveyors - Sanitary conveyors can be sterilized and are designed for medical, pharmaceutical, and food processing applications.
Screw/Auger conveyors - Screw conveyors or auger conveyors are of simple, relatively low cost construction. A screw conveyor consists of a helical flight fastened around a rigid pipe or solid shaft, mounted within a tubular or U-shaped trough. As the screw rotates, material heaps up in front of the advancing flight and is pushed through the trough. Particles in the heap, adjacent to the flight surface, are carried part way up the flight surface and then flow down on the forward-moving side of the heap. These conveyors can handle a wide variety of solid particles ranging from lumps to powders. Lumpy, sticky, or fibrous materials may cause problems in a screw conveyor.
Slat conveyors - Slat conveyors have slats that are spaced apart from one another and are connected to a chain. Slat conveyors are similar to belt conveyors because the item being transported retains its position relative to its surroundings. Since the slats move with the items being transferred, their placement and flow can be controlled. Slat conveyors are ideal for heavy items that could damage belting.
Sorting conveyors - Sorting conveyors are used for merging, identifying, inducting, and separating products to be conveyed to specific destinations.
Table top conveyors - Table top conveyors are ideal for conveying bulk food, parts or packages for assembly or product packaging lines. These conveyors may be integrated into existing conveying systems or used as standalone conveyors.
Tow line conveyors - Tow line conveyors are used to move carts, truck, etc., along a fixed path. The carts are attached to the conveyor using a tow-line and they are pulled along the floor by a motor. This tow-line can be located above, in the floor, or on the floor.
Trolley conveyors - Trolley conveyors are a continuous loop of chain or cable that is suspended from a formed or structural track with carriers attached periodically to hang or contain products. Overhead trolley conveyor systems are frequently used in automated or semi-automated painting systems for moving product through the cleaning, painting and drying operations. They are also used for a variety of other applications such as transporting parts between operations, providing a continuous supply of empty cartons, carrying parts overhead during a natural drying or cooling operation and many, many others. These conveyors can be designed to transport loads up to several thousands of pounds if needed. One of the values of overhead trolley conveyors, besides being overhead and out of the way, is they can handle odd shaped parts that are difficult to convey on belt and roller type conveyors.
Vertical reciprocating conveyors - Use a single platform, forks or cage to lift or lower loads between various levels in intermittent flow operations.
Vertical continuous conveyors - Use multiple platforms, forks or cages to lift or lower loads between various levels in intermittent flow operations.
Vibrating conveyors - Consist of a trough supported by tuned springs and/or hinged links having a drive system. The drive system is arranged to oscillate the trough, causing solid particles to be moved along the trough.
Washdown-capable conveyors - Washdown-capable industrial conveyors are also associated with sanitary or hygienic applications.
Performance specifications for industrial conveyors include:
- Maximum load
- Load capacity
- Volume of material transported
- Mass flow of material
- Number of pieces per minute.
ASME B20.1 - Safety standard for conveyors and related equipment
BS 4531 - Specification for portable and mobile troughed belt conveyors
BS 8438 - Troughed belt conveyors - specification
BS EN 12882 - Conveyor belts for general purpose use - electrical and flammability safety requirements
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