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Time was when all hammermill carne under the generic title of "pulverizer," which was quite appropriate as it aptly described the kind of work to which they were, in those days, almost exclusively applied. This duty consisted largely of such work as pulverizing limestone for various purposes: agricultural flour, glass sand, tube mill feed, and so forth.
This was work for which the hammermill was and is preeminently well suited, and large numbers of them are used today for such service. The field has however in recent years been greatly expanded. The following list, while not comprehensive, includes some of the more important present-day applications:
- Agricultural limestone.
- Grits.
- Glass sand, or flour.
- Raw material s for cement manufacture.
- Coal and coke crushing.
- Preparation of tube mill feed on several nonabrasive materials.
- Gypsum crushing and pulverizing.
- Shale crushing.
- Grinding hay and grains for chopped feeds.
- Manufactured sand for concrete aggregates.
- Commercial crushed stone production.
- Dry crushing of ores for dry or wet concentration.
Not all of the uses listed can, in our opinion, be considered as economically sound applications for the hammermill. This machine cannot be expected to
operate economically on abrasive feed, and it should not be so applied unless there are strong reasons for doing so. Generally this narrows itself down to cases where no other type of crusher wilI deliver the type of product required; occasionally the high reduction ratio of which they are capable wilI dictate their use in temporary jobs where the cost of a two-stage set-up of more economical operating characteristics would more than offset the cost of the single hammermill plus the expected cost of maintenance. A case in point to illustrate the latter condition is that of pilot plant testing in the development of new mining properties. |
