Raymond Series 3 Imp Mills are available in seven sizes, with capacities from 250 to 100,000 lb/hr and feature heavy-duty all-welded plate construction designed to provide 24-hour-a-day dependability and long life.
Standard Imp Mill Systems
A typical system consists of the Imp Mill with either rotary or vibratory feeder, elevated in-stream classifier, system fan and cyclone.
Imp Mill System with Flash Drying
The Raymond Imp Mill system has the flexibility to both pulverize and dry the material simultaneously. The Imp Mill system with flash drying requires a source of heated air, which can be in the form of a fired air heater or waste heat source. The heated air is used to flash dry the material as it is pulverized and swept from the mill. Depending on the initial moisture content of the feed, a portion of the dried product may be combined with the moist feed material in a double paddle mixer. This “conditioned” feed is easier to handle and is more efficiently dried and pulverized. A vent is provided to remove a portion of the moist air and the balance of the warm air is returned to the system where it is mixed with fresh, warm air coming from the air heater.
Imp Mill System with Flash Calcining
In addition to free moisture, some materials, such as gypsum, contain chemically-bound water, which must be removed in order to change the physical characteristics of the material. This process, known as calcining, can be easily accomplished with a Raymond Imp Mill system.
Essentially similar to the Imp Mill system with flash drying, the Imp Mill system with flash calcining is provided with a number of special features which make it suitable for the higher temperatures involved. Our experience in the processing of gypsum, by-product gypsum and waste wallboard provides our customers with a single source of equipment supply for processing gypsum and the manufacturing of gypsum wallboard stucco.
Because the Raymond Series 3 Imp Mill system can be configured in a number of different ways, it is capable of pulverizing, classifying, drying, calcining and beneficiating various materials.
Materials of Construction
A selection of construction materials is available to ensure long life and efficient operation with a wide variety of abrasive or corrosive materials, or for applications that require special treatment. These materials can be incorporated in the Raymond Imp Mill’s housing, shaft, housing liner, hammers and hammer disks, as well as ductwork and classifiers. They include abrasion resistant steels, stainless and other corrosion and heat resistant alloys, special overlays, coatings and liners.
Raymond supplies high efficiency cyclone collectors for its Imp Mill systems to separate the entrained pulverized solid particles from the airstream. Air exiting the cyclone is normally recirculated to the mill, with a small portion vented to a secondary collector, usually of the fabric filter type, or the full air stream may be directed to the secondary collector.
When operated in closed circuit with an elevated instream classifier, oversized particles are continuously returned to the grinding chamber until they are reduced to the required fineness. This is not only provides good particle size control, it also improves the mill’s grinding efficiency.
A variety of different types of classifiers, which can meet the requirement of almost any application, are available for the Raymond Imp Mill system.