A conventional IP55 inverter-rated 4 pole motor drives the mill via a reducing pulley and belt. The package is designed to mount up to a (30kW) 180L frame flange mounted motor with installed power selected to match processing capacity.
Power and rotation transfer to the carousel and mill roller is via a specially stiffened drive shaft (7) mounted within an oil-lubricated double roller bearing transfer assembly. The purpose of the arrangement being to negate runout and stabilise milling performance.
The mill housing is a self-supporting structure containing the inlet, milling and discharge sections.
The mill housing is readily serviceable and designed to be serviced by a single technician; within the majority of Safe Working limitation. The maximum lift weight of removable Housing items including the wear ring is 24kg.
The entire mill service is executable in-situ by progressively dismantling components from the machine as they become visible during disassembly – ensuring a systematic and progressive maintenance approach is always achieved.
The inherent flexibility provided by the IIT modular mill is maintained in M350. In M350 we have moved this “swap out” concept forward to the exchange of only the mill roller carousel.
Servicing is thus limited to sub-assembly replacement and key item service kits to minimise stock holding, offline periods, and service time.
The mill housing is supported on a robust plinth through which the main bearing housing is installed, and power transferred. This assembly transfers any natural or induced vibration to the machine support base frame.
The inlet assembly receives raw and recycled feedstocks and introduces them into the mill module via a security mesh to prevent oversize and foreign body ingress.
Once material has passed through the mesh it is received into the flow balancing cone where, through the combined action of gravity and mill rotation it is continually and evenly fed onto the spreader plate.
The spreader plate guides the material to the outer gap; or annulus, where it drops down into the grinding zone. This dynamic centrifugal feed system ensures an even load distribution in the grinding zone with a well-balanced milling force between the ring and rollers.
Material residence time in the non-captive bed grinding zone is generally less than a second, making a major contribution to the m-series mills’ low relative specific grinding energy - kWh/t.
The milling action in the IIT machine is achieved when coarse material passes through a grinding zone, where it is subject to a high crushing force and becomes comminuted. This grinding zone is formed by a static ring and dynamically rotated rollers.
The milling or grinding ring is supported between two specially constructed body sections. The ring is executed in Hardened and Tempered EN8 or similar hardened steels as a consumable and sacrificial (wearing) part.
The grinding rollers are executed in high chrome irons as standard.
The M350 discharge assembly is specially constructed to enable ATEX compliance, minimal solids hold up and ease of cleaning.
All wear surfaces have been profiled to promote powder flow through the hopper to the outlet connection.
The discharge assembly is provided with a high level blockage sensor (tuning fork type).
The outlet is provided with a T section to allow configuration for single pass milling, or classification with either feed to the mill or direct to the classifier to pre-strip in-specification material.
Due to the rotary action it is inevitable vibration arises within the machine as a result of the milling action creating unbalance within the machine. To overcome transfer of this vibration to the machine components we have isolated the mill from the drive assembly and the main support frame.
The mill and motor are isolated from each other via the use of a drive belt and mounting both onto a common frame which is isolated from the support frame with anti-vibration mounts.
The entire assembly is designed to support the static and dynamic vibrational loads of the operating mill without requiring expensive foundations or complex fixings.
Additional vibration isolation from the building can be achieved through the use of suitable isolation matting or mounts.