Why is the correct speed on your vibrating screen important?
Vibratory screens on mobile machines have very specific design criteria. These include screen angle, G-forces and operating speed. Screen angles play a lesser role, as you can adjust the angle based on the application at hand.
The screen operating speed is one of the most common causes of screen inefficiency. Operating the screen at a lower speed than designed usually results in the following:
- Material carry-over – improper stratification and separation
- Screening media (mesh) blinding
- Excessive screening media wear
- Screen box “banging” on the support structure
- Isolation spring failures
- Improper screen stroke characteristics
To verify the screen’s operational speed, use a tachometer to measure the screen shaft’s rotational speed. Each machine has a unique operating speed; check with your HelpDesk team to determine the required speed for your specific machine.
- Access the screen shaft on the opposite side of the drive by removing the cover.
- Start the screen box and measure the speed with the tachometer.
If the screen box speed is found to be too low, adjust the flow control valve to the screen (if fitted). If no flow control valve is installed, the hydraulic supply pump will need to be replaced. This is typically required when the internal gear set has worn to the point where the designed oil flow can no longer be achieved.
For newer machines, check the screen’s operational speed every six months. For older machines, the speed should be checked more frequently to ensure efficient screening performance.
