Precision Control: The Technical Guide to Roller Crusher Gap Adjustment
In the production of high-quality manufactured sand, the fineness modulus (FM) is the most critical quality indicator. For a Hydraulic Roller Crusher, the ability to maintain a precise and stable gap between the two rollers is what separates a professional operation from a mediocre one.
This guide explores the mechanics of hydraulic gap control and how to optimize it for different material requirements.

The science of the gap: How hydraulic cylinders maintain constant pressure to define the final product size
1. The Role of the Hydraulic Shim System
Unlike old-fashioned manual bolt adjustments, modern hydraulic rollers use a combination of hydraulic pressure and mechanical shims (spacer plates).
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Stability: The hydraulic cylinder provides the locking force, while the shims ensure the rollers cannot move closer than the set minimum distance.
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Safety: The system acts as a giant spring. If a non-crushable object (tramp iron) enters, the hydraulic pressure spikes, and the “movable roller” retreats to prevent shaft breakage.
2. Step-by-Step: Adjusting for Fine Sand (0-5mm)
To achieve a high yield of 0-5mm sand, follow these technical parameters:
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De-pressurize: Safely release the hydraulic system pressure via the control valve.
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Shim Selection: Add or remove high-precision steel shims. For 0-5mm sand, the physical gap is typically set between 2mm to 4mm, depending on the moisture of the pebble.
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Re-pressurize: Engage the hydraulic pump until the working pressure reaches the target (e.g., 8-12 MPa for hard river pebbles).
3. Maintenance of the Adjustment Mechanism
A common mistake in roller crusher gap adjustment is neglecting the sliding surfaces.
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Lubrication: The sliding bearing blocks must be greased weekly. If they seize, the hydraulic cylinders cannot adjust the gap evenly, leading to “tapered” roller wear.
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Parallelism Check: Periodically measure the gap at both the left and right ends of the rollers. A deviation of more than 1mm can cause uneven motor load and premature bearing failure.
Conclusion
Mastering roller crusher gap adjustment is essential for any plant manager aiming for a high-quality finished product. By combining hydraulic power with disciplined maintenance, you can maximize both your sand quality and your equipment’s lifespan.
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