Vibratory conveyors work by causing the the product which is to be conveyed to follow a trajectory in the desired direction. There are various methods for providing this movement, including mechanically, electromagnetically or using an out-of-balance drive. In all cases, the conveying surface, or trough, will vibrate while the frame or base of the machine will not. It is important that all the energy is directed into moving the conveyed product, rather than the support or surrounding steelwork. At KMG we design every vibratory conveyor for food use.
How Electromagnetically Driven Vibratory Conveyors work
Electromagnetically driven vibratory conveyors run at natural frequency. A pulse of power is sent to each electro-magnet every 40ms (25Hz) and the natural frequency of the machine is set to match the drive frequency of 25Hz. When the magnet is actuated, it pulls back the trough at natural frequency, the leaf springs are then released causing the conveying surface to move forwards. These types of vibratory conveyors work because there is a mix of horizontal and vertical force incorporated into the vibration, thereby lifting the conveyed product by a very small amount and propelling it gently forwards in the trajectory that you can see pictured below.
Electromagnetically driven vibratory conveyors are ideal for conveying all types of snacks, biscuits, cereals and pet food. They use very low power and are designed to readily stop and re-start in response to downstream demand. Electromagnetically driven vibratory conveyors will usually run at a very low amplitude and provide a very gentle, almost flowing movement. Our electromagnetically driven vibratory conveyors can even be designed to run slightly uphill.
This type of vibratory conveyor will need tuning from time to time.
How Mechanically Driven Vibratory Conveyors work
Mechanically driven vibratory conveyors work by incorporating a high powered shaking drive to the conveying surface or trough. Again, there will be both horizontal and vertical aspects to the forces generated. These are heavy duty conveyors which would typically be used for heavy, dense products for example whole potatoes. Mechanically driven vibratory conveyors will typically run at an amplitude of 8-10mm. They use considerable more power than an electromagnetically driven vibratory conveyor, however they are brute force machines which will run for many years without maintenance. They are designed to run continually and do not take kindly to start/stop operation. Have a look at our potato preparation page here to find out more.
How Out-of-Balance Vibratory conveyors work
Out-of-Balance vibratory conveyors work by oscillating in a horizontal plane and so are considered a very gentle way of conveying product. A drive unit with 4 rotating masses pushes or pulls the trough such that there is a slow forwards movement which brings the product forwards and then a fast backwards movement which leaves the product where it is, thereby conveying product forwards. Out-of-balance vibratory conveyors can be used to convey over very long distances, even over 16 metres, however they will not convey uphill. They can also be used for inline storage or for product conditioning. Have a look at this page for more information.
Steelwork, supports and robust designs
As I alluded to above, its critical that the propulsion is directed only to the trough and conveyed product, the last thing you need is for your conveyor stand to start vibrating and walk itself out of the factory. Another disadvantage of vibrating conveyors is that they can literally shake themselves apart. Anyone can design a vibrating conveyor, the really skill lies in designing a vibratory conveyor which will last for decades. At KMG, we have decades of experience in knowing how vibratory conveyors work and you can be confident that we know how to avoid the pitfalls.