PARTICULATE FILTER

摘要

The present invention relates to a hemispherical or torispherical particulate filter block for filtering particulate contaminants including microorganisms like cysts, bacteria and viruses while at the same time providing for relatively high flow rates over long period of time. The invention is especially useful for incorporation in a water filter for filtration of water under gravity which removes the above contaminants in addition to chemical contaminants. Of the methods known in the art, filtration is the most widely used, as it is relatively inexpensive and does not require continuous supply of electricity. However, filters have the problem in that either that are not able to remove all the impurities in water or choke rather fast and need to be replaced. The present invention is aimed at solving this problem. Accordingly, the present invention provides a hemispherical or torispherical particulate filter block comprising a first layer of particles of 30 to 60 mesh size and a second layer of particles of 60 to 200 mesh size integrally bonded together with a binder.