Method of Operation

For the economical size reduction of natural and synthetic rubber of any kind, in form of bales, sheets or chips, vulcanized or un-vulcanized, with or without textile reinforcement, PALLMANN offers Ultra-Granulators™, series PS-C.

The rubber bales are fed by hand or via a conveyor belt into the Ultra-Granulators™, series PS-C through  a patented infeed chute  with shuttle flaps that guarantees a guided material feeding and a dosed material intake.

The material is the granulated to the desired size by means of the specially designed guillotine rotor; the open design, without a traversing shaft and with a high momentum flywheel, allow a low friction and therefore temperature gentle size reduction.

The particle size is determined  by the screen mesh size installed in the knife mill.  A pneumatic aspiration system is installed downstream from the rubber granulator in order to discharge the heat produced during the granulating process and also to transport the granules.

The machine is easily accessible for quick and thorough cleaning as well as for knife exchange as the upper part of the housing can be hydraulically swung open.  Low downtime is guaranteed as the rotor and  the stator knives are adjustable outside of the machine and the screen is easily exchangeable.

Material transport can be performed mechanically or pneumatically. Standard one, two or three step size reduction systems can be offered.  We specialize in custom designed complete production lines.

One Step Preparation

In cases where relatively simple types of rubber such as NBR, SBR and EPDM are to be granulated from a standard bale size to granule particle sizes smaller than 10 mm, the granulating process can be often performed in one step. 

If the addition of a dusting agent such as talcum or zinc stearate is required, the dusting agent is injected directly into the cutting chamber via a dosing rotary airlock as well as a high pressure blower.  Therefore, right directly after the cut, the surfaces of the cut granules are dusted thus preventing caking.  Overdosed dusting agent is separated from the granules by means of a recovery system and then reused.

Sample One Step System

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Two Step Preparation

If standard rubber bales from relatively non-sensitive types of rubber are to be reduced to particle sizes smaller than 4 mm, granulating systems operating on a two step principle are used.

A PALLMANN Ultra-Granulator™, series PS-C with guillotine rotor is used for the precutting of the bales.  Downstream fine granulation is also performed on a PALLMANN knife mill equipped with a guillotine rotor.  The rubber bales are fed by hand or  by means of a conveyor belt into the Ultra-Granulator™, series PS-C and cut into pieces smaller than 40 mm.  An additional conveyor belt transports  the rubber pieces to the downstream fine granulating system where the product is granulated to the desired particle size which is determined by the mesh size installed in the knife mill. A pneumatic aspiration system is installed downstream from the rubber knife mill in order to discharge the hat produced during the granulation process and also to transport the granules.

The addition of a dusting agent such as talcum o r zinc stearate is necessary for these two granulating steps.  The dusting agent is injected directly into the cutting chamber via a dosing rotary airlock as well as a high pressure blower.  Therefore, right directly after the cut, the surfaces of the cut granules are dusted thus preventing caking.  Overdosed dusting agent is separated from the granules by means of a recovery system and then reused.

Sample One Step System

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Applications

Natural or Synthetic Rubber Bales Sheets Chips Vulcanized or un-vulcanized

Technical Specifications