IMPROVE- MENTS IN FILTERS FOR PURIFYING AIR AND LIQUIDS
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by Charles Weightman Harrison at
the Office of the Commissioners of Patents, with his Petition, on the
22nd September 1858.
I, CHARLES WEIGHTMAN HARRISON, of Woolwich, in the County of Kent.
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN FILTERS FOR PURIFYING AIR AND LIQUIDS," to be as follows:-
The first part of my Invention relates to means whereby air on its passage
within or out of dwellings, ships, and buildings, or erections generally, may bo
filtered or purified of noxious or offensive gases. I effect this object by
causing the currents of impure air to be brought into intimate contact with a
regulated surface of carbon or other similar material, which shall. by its
absorbent or oxidising properties deprive such air of unpleasant or injurious
odors. The construction upon this principle of air filter or ventilator, which I
have found it most couvenient to form, and to be effectual in use, consists in
placing a number of moulded carbon plates in a frame at a small distance apart
one from another. The air being allowed to pass only through the narrow spaces
between the plates, its impurities become destroyed by the oxidising action of
their surfaces. I do not, however, confine myself to this particular arrange-
ment. I find it of advantage to form carbon air filters with an indented or
a corrugated surface.
The second part of my Invention refers to portable water filters, and my
improvements herein comprise the construction of a central chamber or well
in the filter, and the combination of pumping apparatus. with portable filters,

page_text: whereby the water may be conveniently drawn. I prefer to form these filters
of moulded carbon, or partly of moulded carbon and partly of earthenware, and
of a conical or tubular shape.
The third part of my Invention refers to the construction of filtering cisterns
eapable of affording large supplies of pure water. In a reservoir or cistern of
suitable size, I place a number of porous plates of moulded carbon or other
material, so as to form divisions, the edges of the plates fitting into grooves in the
sides and bottom of the cistern, where they are made water-tight; I then cement
the plates together, in pairs, at the top, by means of a strip of carbon or slate
and marine glue or gutta percha, and I fill up the spaces between every pair
of plates with sand or other loose matter; over the whole I place a perforated
tray or slab covered with coarse sand or grit. The water entering at the top
passes through the sand and moulded carbon, from whence it is drawn by
appropriate connections. Instead of plates, I sometimes employ hollow tubes
of moulded carbon, the interstices between them being in like manner filled
with sand, and the purified water drawn off either at the side or bottom as
desired.
The fourth part of my Invention consists in forming decolorizing filters of
vegetable carbon and bone dust, these are well mixed together, either alone or
with sawdust, then moulded in any desired shape, and afterwards burnt in a close
oven. In place of bone dust I sometimes use pure phosphate of lime, alumina,
or an oxide of manganese or other metal, to mix with the carbon previous to
moulding. Or, I mould together alternate layers of carbon, and any of these
substances. I also manufacture highly porous filters by moulding the sawdust
of cork or other light wood and bone dust, without the usual combination of
carbon, and I afterwards carbonize these materials in close vessels.