Vibratory conveyor
Vibratory conveyors are mechanical conveying devices for bulk goods of all kinds, in which the medium to be transported is moved by means of linear vibrations . They belong to the group of vibration machines , which also includes sieving machines .
functionality
The vibratory conveyor moves diagonally upwards in the transport direction and back. During the forward movement, it lifts the material to be conveyed depending on the throwing code and pushes it in the desired direction. When returning, the conveyed material stops because of the inertia and the downward movement (and the associated lower friction). With the next forward oscillation, the material is pushed a little further forward. This process is repeated with the frequency of the vibratory drive. The speed of the material feed is determined by the amplitude width and the frequency of the vibration of the conveyor. For each oscillation, the material is pushed on by approximately the horizontal vector of the oscillation amplitude.
application
Vibratory conveyors are very robust conveying devices that require little maintenance and are suitable for bulk goods of various grain sizes. Their area of application ranges from powdery goods to gravel or rubble. In addition to their robustness, another advantage is their high vertical load capacity, which is only limited by the design of the suspension. They still work perfectly under high silos with the corresponding material pressure, whereas conveyor belts block or wear out quickly with the same application. In addition, they are fairly insensitive to jams or blockages in the conveying path. While other conveyor systems such as screws or belts fail due to overload, vibratory conveyors usually work themselves free again.
A disadvantage is that they only work optimally in an approximately horizontal direction.
A special type of bowl feeder are the vibratory bowl feeders , which are suitable for sorting individual parts.
construction
Vibratory conveyors consist of the actual conveyor device (conveyor trough or conveyor pipe), the drive part and an elastic suspension. All components of the conveyor, with the exception of the suspension, must be designed to be very resistant to bending and torsion in order to transmit the vibrations evenly to the entire device and to avoid fatigue fractures for as long as possible. That is why they are often stiffened with many rib and gusset plates . Because of the abrasion caused by the conveyed material, the sliding surfaces are usually covered with easily replaceable wear plates. The suspension consists either of elastically mounted steel ropes or rods, rubber pads or springs.
Imbalance drive
The unbalance motors used for vibratory conveyors are usually maintenance-free three-phase motors with adjustable unbalance weights mounted on one or both shaft ends. The amplitude of such vibratory feeders is changed by manually adjusting the imbalance. The frequency is determined by the speed. Two drives in opposite directions are always required, as a single motor would produce a circular movement and not the desired linear oscillation. The running time of such conveyors is only limited by the service life of the motor bearings and the service life of the wear plates, which is why they are mainly used for large and long-running systems.
Oscillating armature drive
In the case of the oscillating armature drive , a coil with changing field strength sets a heavy, spring-mounted armature into oscillation, which is then transmitted to the conveyor. These drives are more complicated, more expensive and not quite as robust as unbalance drives, but they offer significant advantages: By changing the frequency and / or the coil current, the transport speed can be set within wide limits. For example, large quantities can be conveyed quickly during weighing and still dosed very finely at the end of the process. In addition, only one drive is required with this design.