The PRECIOUS Hammer Mills are durable utility grinders capable of grinding most free-flowing materials. Hammer mills operate on the principle that most materials will grind or crush upon impact with the hammers. The Precious Hammer Mill are designed for fine crushing of soft up till medium hard, non abrasive and non adhesive materials, such as bituminous coal, limestone etc.
A large application of hammer mills can be seen in cement factories and in lime works foe preliminary crushing of bituminous coal for treatment of lime stones, for sintering purpose and according to the needs even in other industrial branches. Their advantages is a high degree of crushing, high performance, a possibility of change of granulometric composition of the product within a large range an easy access to the internal compartment and consequently an easy operation and maintenance of the machines. Operating area of the Precious hammer mills can be heated by means of hot gases and thus conditions are created for treatment of materials with a higher degree of moisture.
Main parts of the PRECIOUS hammer mill are a welded case, rotor with hammers, grates and drive. The case of the hammer mill consists of lower and upper three parts portions. The middle part of the upper portion is fixed to the charging hopper, while the lateral parts which are lined with grooved armours can be lifted around revolving hangers either hydraulically or in case of smaller sizes, manually. In the lower part of the case are adjustable discharge grates, the position of which as against the concerned space can be adjusted by means of upper and lower regulation, placed on the exterior side of the lower part of the case. In the crushing compartment delimitated by the upper part of the case and by the grates turns the rotor consisting of a shaft and of a number of disks through which are passed bars of hammers. On the bars are fixed the hammers in a rotary way. The drive consists of a dust-proof electric motor of a closed structure, connected with a flexible coupling or through transmission by means of vee- belts with shaft of rotor. A particular attention during the stage of development of hammer mills was devoted to easy service and maintenance. Hydraulic or mechanical lifting equipment facilitates access to the whole upper half of the rotor without a difficult disassembly of the entry part; thus it shortens substantially outage time during repairs of the machines and during the exchange of hammers.
Operation of the mill:
The material is fed into a hammer mill from the top and by gravity falls into the grinding chamber. The material is contacted by a series of rotating hardened hammers. The material is ground by repeated contact with these hammers, contact with the walls of the grinding chamber, and particle to particle contact. The material remains in the grinding chamber until it is suitably sized to pass through the perforated screen that covers the bottom half of the grinding chamber. We offer interchangeable screens with whole diameters from 2" to 1/64" to allow for course or fine grinding of most any product. The output (volume) of the hammer mill is dependent upon the screen size, shaft speed (normally 3,600 rpm), and the configuration of the hammers. We offer hammer mills with bottom discharge (gravity fall) and we offer hammer mills equipped with material handling fans (recommended for finer grinds). Precious hammer mills may be belt driven or direct driven to fit your specifications. As a consequence of symmetric design the mills can be operate in both directions of rotor rotation they are reversing. The material to be crushed arriving in to the crushing area through the entry orifice comes into a direct contact with the hammers; the hammers rotating at a speed of 35 � 60 m.s -1, both crush the material and throw it against the armour plating of the upper part of the case. Here the material is crushed furthermore rebounds back and is pulled down by the hammers to the grate, where the milling process comes to the end. Material of a required fineness falls down through slots in between the grate bars. Dimensions of the slots can be chosen according to the needs from 10 to 40 mm, the slot of 10 mm width being the standard dimension. Composition of the granulometry of the product going out can be changed within large limits by changing the arrangement of the outlet grate and of the milling path. We can configure our hammer mills to best suit your application. We are happy to test grind any product free of charge. If you are interested in sending a product for test grinding please contact us. By test grinding your product we are able to prove the capability of our hammer mills and determine the proper model and set up (bottom discharge or material handling fan, and belt drive or direct drive) to suit your needs.
- Type of material to be crushed, its size, specific mass, hardness, moisture, temperature, knock-off rate according to L.A., abrasion according to bond and other properties.
- Required output of the mill in tons per hour
- Required fineness of the outgoing product.
- Operating voltage for electric motor, type of current.
- Layout sketch, considered location of mill
- Number of operating hours of the mill per day.
- Basic arrangement with the closed milling path is used especially for crushing limestone for sintering purpose and for grinding similar types of material. Fineness of the outlet product thus obtained is of 0 �3 mm with grate slots of 10 mm.
- A Closed milling path armour removed over the dividing level is used for materials with higher moisture content, for example for limestone up till 6% of H2O, and in other cases when a partial glueing of grate slots occurs.
- Arrangement with the open milling path is used for crushing bituminous coal for coking and for coarse grinding of limestones, of cement related raw material convenient for the technology of crushing in hammer mills. Achieved fineness of coal is of 0 � 3 mm for limestones for cement related raw materials and for other appropriate materials it is of 0 � 10 mm.
- Arrangement with an open milling path at a random place of the milling path. It is used for less easily crushable materials mentioned in the previous variant.
- Grinds almost anything!
- Large output, to 800 lbs. /hr
- Large effective screen area with screens from 35 meshes to 100 mm!
- Fold back design for easy cleaning and inspection
- Stainless steel model available
- Options include side discharge, blower discharge, custom hoppers and discharge chutes
- Three models available for even higher throughput
- Safe - twin safety switches prevent mill from being started with hood open
- Minimal power requirement
Materials that have been grind include: Alfalfa, Bones, Bottles, Bread, Casein, Ceramics, Cereals, Charcoal, Chemicals, Clay, Coal, Copra, Cork, Corn, Cotton seed hulls, Drugs, Feathers, Food, Fruit, Gelatin, Glass, Grains, Graphite, Gypsum, Kaolin, Limestone, Macaroni, Marble, Mica, Newspaper, Oilcake, Pepper, Phosphates, Plastics, Refuse, Roots, Sawdust, Silage, Soap chips, Soya beans, Spices, Straw, Tobacco, Vegetables, Wheat, Wood by-products, X-ray film.......
Technical: PRECIOUS'S engineering staff is also available to assist in designing a system to efficiently handle your product. Whether you need a complete layout or simply need to fit a new piece of equipment into your existing layout, our staff is available to assist you. We are also proud to offer conveying equipment (mechanical or pneumatic) and storage equipment (collectors and piping systems).
Marketing: PRECIOUS'S competent sales staff is always available to discuss your application and recommend a model and configuration to suit your needs.