When the Symons brothers invented the cone crusher over 60 years ago, they employed the principle wherein the length of the crushing stroke was related to the free fall of material by gravity. This permitted the material being crushed to fall vertically in the crushing chamber; and in effect caused the particles to be crushed in a series of steps or stages as the particles got smaller due to the crushing action. This also helps to reduce the rate of wear of the liners since the sliding motion of the particles is minimized.
Process Research
During the last decade the Process Machinery Division of Rexnord has developed a unique process knowledge about the effects of cone crusher design parameters such as speed, throw and cavity design on crusher productivity. This knowledge was gained through extensive test programs both at our Mineral Research and Test Center and at customers plants employing the well proven Symons cone crushers of various sizes. These tests indicated that crusher productivity could be greatly increased for a given size crusher, when the unit is beefed-up mechanically.
2390 Omnicone
The 2390 Omnicone crusher is the result of a joint effort by Rexnord Inc. and Bougainville Copper Ltd. The project was conceived in 1983 as a way for Rexnord to market its advanced process technology gained through dedicated research programs as well as a way for Bougainville Copper to increase the concentrator throughput and efficiency by increasing power input at each crushing station by a very substantial amount.
Design
The 2390 Omnicone, although using the existing Omnicone mechanical design as a basis, went far beyond a simple extension of the line. The design power rating for a 7 ft. Omnicone would have been 500 hp if we had followed our previous scale-up of the Omnicone line. Our target was to utilize 1000 hp and thus the drive train needed to be uprated. But just connecting a larger motor does not mean that you can efficiently utilize this power. On all cone crushers there are three limits to productivity. These are power input capability, crushing force available and volumetric capacity. In order to match a 1000 hp capability, we need also address the other two limits — force and volume.
Design Features
The 2390 Omnicone has the following advanced design features for ease of operation and maintenance and increased productivity.
- Cavity clearing for reduced downtime.
- Balanced design. Minimizes foundation requirements.
- Adjusting under load with automation capability for ease of operation and increased productivity.
- Ability to select-different speed and throw combinations to optimize application.
- Maintenance free seals.
- One head for all cavities. Saves on parts stocking.
- Liner thickness of up to 8 inches (200 mm). Allows longer period of operation between liner changes and thus lower downtime.
- 1000 hp capability to give maximum productivity.
- Ease of maintenance. All assembly and disassembly is done from the top or the side and requires minimum head room.
- Rotating bowl for even wear of the liners and same setting around the crushing cavity.
- Sleeve bearings used throughout for trouble-free operation, ease of maintenance and low cost replacement.
- Fits on the existing 7 ft. Symons foundation with minor modifications to the foundation.
- Has a crushing force monitor to safeguard against frequent overloads.
- Large committed resources to conduct process and design research which will provide productivity improvements in the future.
Testing
The crusher was completely assembled, the hydraulic systems were checked, and the crusher was run no-load to check operation at the anticipated speed and throw combinations.
Strain gage testing was also done using a simulated crushing load. This work confirmed our finite element analysis and the crusher was shipped to site.
Early on, failures were experienced on the socket liner, thrust bearing and eccentric bearing.
Preliminary results to date indicate that the crusher with small diameter liners is performing as follows:
