The Coperion K-Tron K3 line of vibratory feeders features improved high accuracy thanks to innovative patent-pending drive technology. They are available in a standard design or a hygienic easy-to-clean design.
Q. What mistakes are made when selecting vibratory feeders?
A. It’s not an all-purpose device. It is only for free flowing material. We do not have an enforced material motion like in a screw feeder. But sometimes facilities want to compromise on this because of the advantages.
Q. Are there special design considerations?
A. One point to be considered is we don’t have agitators inside, so it is more sensitive to blocking. To remedy this, we have a technology called ActiFlow™, which uses vibration to break bridges in the hopper. It will not break the bridges. And if it is too strong, it will compact the material and then it bridges even more than before. The device measures how much material is on the tray and calculates from there. Many people prefer this over a mechanical agitator since you don’t have to clean something inside because it’s already outside of the hopper.
Q. How does the K3 differ from other alternatives?
A. We’ve talked about the pendulum shock-absorber technology. There is nothing like this on the market. What we haven’t talked about is the hygienic design. We have a device that needs to vibrate. Usually to allow these vibrations, you have gaps. But for hygienic environments you try to avoid gaps. We designed a silicone boot, which covers the whole drive. There are no gaps. It is completely enclosed.
Another is the controller itself. It is a closed-loop control. We measure the motion 1,500 times per second. And by measuring the motion, we can adapt the excitation signal of the coil in real time. Others do not measure any vibration, they only increase the signal or lower it. We measure the motion and compare it to the excitation and then we see if we are in resonance, and we drive our vibratory in resonance frequency.
Most of the devices on the market avoid resonance frequency. For example, if you are on a swing and you are moving in the right frequency, with a little motion you get a big oscillation. This means you’re in resonance. But if you move in a much faster frequency, you get almost no oscillation. This is what most devices on the market do.
We measure the current 25,000 times per second and make adjustments to ensure a clean sine curve and very smooth motion. This reduces noise and vibration. Compared to other devices, which are pretty simple, it’s very complicated, but it gives us a lot of controllability as well as efficiency. To give you an example, we measured power consumption at a feed rate of 12,566 pounds (5,700 kilograms) an hour. We used only 20 watts of power to feed that amount.
That’s a third of a light bulb. Because we drive it in resonance, we only need a little bit of energy to keep it moving.
Q. Anything you’d like to add?
A. We should talk about the weighing technology, which is a core competence of our company. We build our own scales and controls. If you apply more force to the scale, the vibrating wire is more loaded and the resonance frequency increases. By measuring this resonance frequency, we know how much weight is on the scale. We measure over 100 times a second.
We achieve higher accuracy because the scale is adapted to the environment. We have a demo video (https://bit.ly/k3-feeder) that shows one scale with the filter and one without, both subjected to vibrations. On one you see a noisy signal and on the other one, you see a straight signal.
On the one with filter you can actually see the change in weight signal due to drops falling out and on the other you see nothing because the signal is very noisy. So that’s very impressive.
Something else we haven’t discussed is pressure in the system. Pressure fluctuations can seriously impact the weighing accuracy of a feeding system. This leads to incorrect weight signals, causing erroneous mass flow and poor feeding accuracy. We’ve developed EPC -- electronic pressure compensation. We measure the pressure on the outlet and in the hopper. And if the pressure changes, we compensate this error on the scale electronically.
Coperion K-Tron has over 100 patents for mechanical components and control technologies to our feeding and weighing solutions. This experience allows us to tailor our products and services to the needs of various industries.
For more information, send an email to info@coperion.com or visit www.coperion.com.