Getting the most out of your Jaw Crusher
Difference between Closed Side Setting and Open Side Setting
- Measuring the Closed Side Setting (CSS) or Open Side Setting (OSS) is usually confusing as many methods are employed without understanding consequences.
- CSS is the smallest discharge opening dimension on the jaw.
- OSS is the largest discharge opening dimension on the jaw. It is equal to the CSS plus the throw of the swing stock.
- The dimension on the discharge end of the jaw liners are measured from Peak to Root.
- To measure the discharge dimension, lock out the crusher.
- Check the arrow on the flywheel as this will identify the position of the eccentric shaft.
- When the arrow points upward then the measured value at the discharge end of the jaw liners will be the CSS.
- If the arrow points downward then the measured value at the discharge end of the jaw liners will be the OSS. In this case, the measurement obtained here will need to be subtracted from the eccentric stroke of the swing jaw shaft to obtain the CSS.
Arrow on fly wheel
1 – Look through slotted area on guard at alignment minimum jaw opening
2 – Alignment arrow points vertically up at arrow on shaft end plate
Figure 1 above: Image taken from Sandvik operator manual for QJ341
Figure 2 above: Discharge Setting
Taken from Sandvik Training JAW-ST
Arrow on flywheel pointing upward: X = CSS
Arrow on flywheel pointing downward: X = OSS – eccentric throw = CSS
Figure 3 above: Taken from Sandvik Training JAW-ST
- Use the jaw crusher reverse function on the display screen to get the arrow on the flywheel in the correct position.
- Always measure the CSS with the arrow on the flywheel pointing upward so that there is no confusion with subtracting strokes.
- Take care around the flywheels as the balance weights may rotate the flywheels at any time.
- Try to a keep crushing ratio of 4:1 to get the maximum life out of the mechanical components. Take the maximum feed size divided by the CSS to obtain the crushing ratio.
- Maximum feed size into the jaw is 80% of the feed opening.