Water purifier abstract
A water purifier comprising a primary filter for removing residual
chlorine and other impurities, a secondary filter disposed downstream
of the primary filter for removing microorganisms and antimicrobial
means disposed between the primary filter and the secondary filter.
The water purifier of the invention can be used for long time since
the proliferation of microorganism, which causes clogging of the
secondary filter, is effectively prevented.
Water purifier claims
What is claimed is:
1. A water purifier comprising:
a primary filter for removing residual chlorine and other impurities
in water, a secondary filter disposed downstream of said primary
filter for removing microorganisms, and antimicrobial means disposed
between said primary filter and said secondary filter for enhancing
the filtering life of said water purifier, said antimicrobial means
comprising a water-insoluble antimicrobial agent for exerting antimicrobial
function upon contact with microorganisms to substantially prevent
microorganisms from proliferating between said primary and secondary
said secondary filter being made of hollow fibers;
said hollow fibers of said secondary filter having an exterior
said antimicrobial agent being attached to said exterior surface
of said hollow fibers of said secondary filter.
2. The water purifier of claim 1 wherein said water insoluble
antimicrobial agent comprises a zeolite with copper ions.
3. The water purifier of claim 1 wherein said water insoluble
antimicrobial agent comprises a zeolite with silver ions.
4. The water purifier of claim 1 wherein said water insoluble
antimicrobial agent comprises thiobendazole.
Water purifier description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water purifier for removing
residual chlorine or the like contained, for example, in the city
water and more particularly to the water purifier having a primary
filter for removing residual chlorine and a secondary filter disposed
downstream of the primary filter with the intention of extending
the life of the purifier by preventing the secondary filter from
2. Description of the Related Art
The city water generally contains, although the content is very
small, some amount of residual chlorine which gives uncomfortable
feeling such as odor. In some cases, therefore, the city water has
been filtered through a filtering material such as activated carbon
to remove the residual chlorine. However, there has been a fear
that, if the residual chlorine is removed and if the water is left
in a relatively pure state, microorganism such as bacteria, fungi,
etc. may proliferate and flow out.
As a water purifier for preventing the microorganism from flowing
out, there is an apparatus for example described in the Japanese
Utility Model Laid-Open Publication No. 61-22594 wherein a secondary
filter for removing the bacteria and consisting of a hollow fiber
unit is disposed downstream of the primary filter having granular
activated carbon. The problem of the outflow of microorganism described
above can be avoided with the water purifier described above.
In the conventional water purifier provided with the primary and
secondary filters as described above, however, there has been a
disadvantage that microorganisms proliferate between both filters
and the proliferated microorganisms clog the secondary filter to
considerably shorten the filtering life of the water purifier. In
order to eliminate this problem, there has been an example wherein
activated carbon applied with silver chloride as the primary filter
has been used to suppress the proliferation of microorganism. However,
since the proliferation of microorganism between the primary and
secondary filters has not been considered in the conventional construction,
the filtering life cannot be extended to a large extent.
OBJECT AND SUMMARY OF THE INVENTION
The object of the present invention, in consideration of the problem
described above, is to provide a water purifier having a remarkably
long filtering life by preventing microorganisms from proliferating
between the primary and secondary filters.
The object of this invention is achieved by the provision of a
water purifier comprising a primary filter for removing residual
chlorine and other impurities in water, a secondary filter disposed
downstream of said primary filter for removing microorganisms, and
antimicrobial means disposed between said primary filter and said
The antimicrobial means here can be realized either of the following
methods: (1) in the case hollow fibers made of plastic such as polyethylene,
polypropylene, etc. are used as the secondary filter, antimicrobial
agent is either added to the raw material plastic from which the
hollow fibers are to be made or applied to the hollow fibers, (2)
a antimicrobial filter made by applying the antimicrobial agent
to a nonwoven fabric for example is disposed at the intake port
of the secondary filter, and (3) city water with the residual chlorine
or other sterilizing agent is partially supplied between the primary
and secondary filters.
The antimicrobial agent used in this invention must be harmless
to human body, and preferably it is water-insoluble to extent its
antimicrobial function upon contact with various microorganisms
including bacteria and fungi. A specific example of the antimicrobial
agent, which may be preferably used in this invention, is zeolite
having its skeletal structure containing metallic ions, such as
copper or silver ions, or other inorganic antimicrobial elements.
Other preferable examples are water-insoluble antimicrobial agents,
such as thiobendazole.
As stated before, if the residual chlorine is removed by the primary
filter, there is a concern about the proliferation of microorganism
and the clogging of the secondary filter. In the present invention,
however, the proliferation of microorganism in that part is prevented
as the antimicrobial means is disposed between the primary and secondary
filters. As a result, there is a almost no possibility of clogging
of the secondary filter with microorganism andtherefore the filtering
life of the water purifier is remarkably extended.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional side view of a water purifier of an
embodiment of this invention;
FIG. 2 is an enlarged cross-sectional view of the hollow fiber
assembled in the water purifier;
FIGS. 3(a) through 3 (d) are schematic drawings for explaining
the test procedure for investigating the filtering life;
FIG. 4 is a characteristic chart of the total water amount passed
vs. filtered water flow rate decrease, showing the test result;
FIG. 5 is a schematic drawing showing another embodiment; and
FIG. 6 is a schematic drawing showing one other embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the invention is explained hereinafter
with reference to the drawings in which:
FIGS. 1 through 4 are for explaining a water purifier of an embodiment
according to the invention.
In FIG. 1 a water purifier 1 consists of a main housing 2 and
an inner housing 3 holding an activated carbon filter 7 as a primary
filter and received in said main housing 2 with a hollow fiber
unit 4 as a secondary filter being disposed in said activated carbon
filter 7. Said main housing 2 consists of a cylindrical body 2a
made of a sheet metal, a plastic bottom 2b detachably attached to
the bottom end of said cylindrical body 2a, and a top cover 2c secured
to the top end of said cylindrical body 2a.
Said inner housing 3 is disposed and secured in said main housing
2 by screwing its bottom wall portion 3a into the bottom portion
2b of the housing 2. In the center of said bottom wall portion 3a
formed is an inlet port 3b, wherein a reverse flow check valve 5
is disposed, and to the upstream side of the port 3b connected is
a water supply passage 6b via a connection pipe 6a. The numeral
3d denotes a guide plate. The numeral 2d denotes a bottom cap for
covering said water supply passage 6b, etc. and also serving as
a slip-stop when the water purifier 1 is placed on a table or the
The activated carbon filter 7 received in said inner housing 3
is constituted with a cylindrical support housing 7b provided with
plural of communication holes 7a, and a filter 7c surrounding the
support housing 7b, with the filter 7c being cylindrically formed
with corrugated filter cloth as a porous support applied with activated
carbon powder. The activated carbon filter 7 is held between a support
plate 3c welded to the bottom of said support housing 7b and an
upper flange portion 7d which is in turn depressed with a cap 8
screwed to said inner housing 3.
Said hollow fiber unit 4 consists of a support cap 9c screwed to
a protective housing 9a, with the cap 9c in turn being screwed to
said support housing 7b. To the support cap 9c is connected a filtered
water passage 10c via a coupling 10a and a connection pipe 10b,
with the passage 10c being introduced to outside.
A plurality of hollow fibers 9b are housed in said protective housing
9a. The hollow fiber 9b is made of a tubular body of polyethylene
or polypropylene provided with innumerable micropores 9d. The hollow
fiber 9 is bent in a U-shape and its opening end portion (top end
portion in FIG. 1) is secured with a plastic layer 9e to the top
end of the protective housing 9a.
The exterior surface of the hollow fiber 9b is treated with antimicrobial
treatment. The antimicrobial treatment is to prevent microorganisms
such as bacteria, fungi or the like from proliferating in the space
between said activated carbon filter 7 and the hollow fibers 9b
and is constituted by attaching a antimicrobial agent 11 of for
example silver-ion containing zeolite or thiobendazole to the exterior
surface of said hollow fiber 9b. In order to attach the antimicrobial
agent 11 it has only to put a specified amount of said powdered
antimicrobial agent in the protective housing 9a of the hollow fiber
unit 4 to put a net over the opening as required, to connect it
to the water purifier 1 and to let the city water flow in. This
procedure caused the antimicrobial agent 11 diffusedly adhere to
the exterior surface of the hollow fiber 9b.
The function of the present embodiment is described below.
In the water purifier 1 of the present embodiment, city water is
supplied from the water supply passage 6b, pushes and opens the
valve body 5 enters the inside of the inner housing 3 passes through
the activated carbon filter 7 passes through the micropores 9d
of the hollow fibers 9b, and is taken out of the filtered water
passage 10c. In this flow of water, impurities such as residual
chlorine is first removed by the activated carbon filter 7. Microorganisms
which entered the downstream side of the filter 7 cannot pass through
the filtering pores 9d of the hollow fiber 9b and therefore there
is no possibility of the microorganism flowing out.
In the case of conventional water purifiers, there has been a problem
here that the microorganisms proliferate in the space between the
primary and secondary filters and clog the secondary filter. In
the present embodiment, however, the antimicrobial agent 11 is attached
to the secondary filter of the hollow fibers 9b. Therefore, the
microorganisms which have entered the vincinity of the hollow fibers
9b multiply little and the period during which the hollow fibers
9b are clogged is accordingly extended, resulting in a remarkably
extended filtering life of the water purifier 1.
FIGS. 3 and 4 are for explaining the tests for verifying the effects
of extending the filtering life of the water purifier 1 according
to the present embodiment. FIG. 3(a) is a schematic drawing of the
apparatus of the present embodiment and FIGS. 3(b) through 3(d)
are schematic drawings of the first to the third comparative examples.
The water purifier 1 according to the present embodiment (FIG.
3(a)) is provided, similar to the manner described heretofore, with
a filtering cloth 7d, a filter 7c consisting of activated carbon
powder attached with silver chloride, and a hollow fiber unit 4
made of hollow fibers 9b attached with the antimicrobial agent 11.
The water purifier 21 of the comparative example 1 (FIG. 3(b))
is provided with a primary filter 22 consisting of a filtering cloth
22a and ordinary activated carbon powder 22b, and a secondary filter
23 consisting of hollow fibers 23a. A comparative example 2 (FIG.
3(c)) is provided with powder-state activated carbon 22c attached
with silver chloride. In a comparative example 3 (FIG. 3(d)), the
primary filter body 24 is constituted with a granular activated
carbon 24a attached with silver chloride.
Tests were conducted with water purifiers of the construction as
described above and having the same filtering capacity, passing
10 l of water every other day, and filtered water flow rate per
minute was measured. FIG. 4 shows the test result. The horizontal
axis shows the total water amont (liter) which passed the water
purifier and the vertical axis shows the variance (l/min) in the
measurement of the filtered water flow rate from a reference value
As seen from FIG. 4 in the comparative examples 1 through 3 where
no antimicrobial treatment is applied, the filtered water flow rate
(l/min) rapidly decreased as the passed water amount (in proportion
to the number of days) increased, showing the fact that their filtering
lives are short. In contrast to these, the amount of decrease in
the filtered water flow rate of the present embodiment is 1/3 to
1/6 compared with the comparative examples, showing that the filtering
life is three to six times those of the comparative examples.
While the anti-microbial agent 11 is attached to the hollow fibers
9b as a antimicrobial means in the embodiment described above, there
can be various kinds of variations in the antimicrobial means. For
example, the antimicrobial treatment may be performed by mixing
the antimicrobial agent into the raw material plastic from which
the hollow fibers are manufactured.
It may be also arranged as shown in FIG. 5 that a bactericidal
filter 25 made of nonwoven fabric, to which the antimicrobial means
similar to that described above is attached, is installed at a water
intake port 26a of the hollow fiber unit 26 and is supported with
a net 26b.
Furthermore, while the embodiment examples described above used
a additional antimicrobial agent, the antimicrobial means of the
present invention may be realized for example by introducing a required
amount of city water with residual sterilizing agent of chlorine
remaining as it is into the space between the primary and secondary
filters as shown in FIG. 6.
Since the antimicrobial means is interposed between the primary
and secondary filters of the water purifier according to the present
invention as described heretofore, microorganism is prevented from
proliferating in the space between said filters and, as a result,
the filtering life is remarkably extended.