Note: Descriptions are shown in the official language in which they were submitted.
CA 02396510 2002-07-30
WATER PURIFIER
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a water purifier with an
activated carbon filter having a solid block shape. The water
purifier concerning the present invention can include water purifiers
used for cooking or drinking for ordinary homes, medical offices,
restaurants, and the like.
Description of the Related Art
Conventionally, in Japan, water purifiers with a filter using
granular activated carbon powder have been widely used for removing
disinfectant components, trihalomethanes, and the like by adsorption
and chemical reaction. There have been used sintered activated
carbon block filters formed by combining with aggregate of the
activated carbon powder by sintering.
In U.S.A. advancing informational disclosure, some reports
disclose that weakened polio virus,namely, vaccine excreted from a
living body, sometimes recovers toxicity when it flows in rivers with
feces . In Japan, some reports disclose that in addition to the polio
virus, a plurality of fungi abundantly increase in digestive organs -
these fungi contain six groups of coxsackie virus, ecology virus,
infectious hepatitis virus, adenovirus, and reovirus. Moreover,
U.S.A, has decided removal of viruses such as polio viruses as a
standard of water supply. Poliomyelitis have been sometimes detected
in some regions such as Russia, South-East Asia, Africa, and Latin
America. So, water purifiers are urgently requested which can
effectively remove fungi such as polio viruses, with simplicity,
usability, and cheapness .
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In U. S .A. , there have been popular compressed activated carbon
block filters having a hollow cylinder shape, which are formed of the
mixture mixing activated carbon powder with thermoplastic resin
powder. This purpose is to remove protozoa having a size of several
tens ,u m, bacteria, and the like.
According to the sintered activated carbon block filter of the
above mention, the water permeable area is considerably small in
comparison with the water purifier using a hollow fiber membrane. So,
if the pore is set to be small for improving catching ability of the
sintered activated carbon block filter, the amount of penetrating
water is lowered per unit time at usual water pressure. So, this
activated carbon block filter can not be used as a practical water
purifier.
Then, according to the sintered activated carbon block filter,
it is requested that the particle size of activated carbon powder is
set to be large for increasing the amount of penetrating water per
unit time. Such case, however, induces the problem that a catching
ability is insufficient though the amount of penetrating water is
increased per unit time. That is to say, the sintered activated
carbon block filter does not catch: (1) "brevundimonas diminuta"
hereinafter it is also referred to as "brevundimonas") having a
diameter of 0.3,u m, being generally used for a bacteria-proof in
Japan, and (2 ) "escherichia coli" having a diameter of 0 . 65 ~.c m.
Further, the sintered activated carbon block filter does not
catch: (1) polio virus having a diameter of 25-35 nm; and (2)
"bacteriophage MS-2" being used as a substitution for polio viruses .
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WATER PURIFIER
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As above mentioned the conventional water purifiers are insufficient
in improving catching ability and water permeability.
SLJMMA,RY OF THE INVENTION
The present invention has been accomplished in view of the
aforementioned circumstances. It is therefore an object of the
present invention to provide a water purifier which can increase
catching ability. Further, it is therefore an object of the present
invention to provide a water purifier which can increase catching
ability, and water permeability.
In a first aspect of the present invention, a water purifier
comprises: a container having a room; and a filtering material
disposed in the room for purifying water supplied to the room; and
wherein the filtering material is formed of a sintered activated
carbon block filter having a plurality of pores. Accordingly, in the
first aspect of the present invention, ability is ensured for
catching fungi and particles.
In a second aspect of the present invention, a water purifier
comprises: a container having a room; and a filtering material
disposed in the room for purifying water supplied to the room;
wherein the filtering material is formed of a sintered activated
carbon block filter having a plurality of pores; and wherein the
filtering material has a first filtering material and a second
filtering material characterized in that:
one thing out of the first filtering material and the second
filtering material is formed of a sintered activated carbon block
filter whose average pore diameter is relatively small and whose
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amount of penetrating water is relatively small per unit timed and
another thing out of the first filtering material and the
second filtering material is formed of a sintered activated carbon
block filter whose average pore diameter is relatively large and
whose amount of penetrating water is relatively large per unit time.
Thus, said one thing is smaller than said another thing in the average
pore diameter and in the amount of penetrating water per unit time.
The term of "the amount of penetrating water" means the amount of
water which can penetrate through the activated carbon block
filter, and means water permeability.
In the second aspect of the present invention, said one thing
out of the first filtering material and the second filtering material
is formed of the sintered activated carbon block filter whose average
pore diameter is relatively small and whose amount of penetrating
water is relatively small per unit time. Accordingly, ability is
ensured for catching fungi including viruses and bacterium,and for
catching particles.
Also, in the second aspect of the present invention, said
another thing out of the first filtering material and the second
filtering material is formed of a sintered activated carbon block
filter whose average pore diameter is relatively large and whose
amount of penetrating water is relatively large per unit time.
Accordingly, the amount of penetrating water is ensured per unit time
to improve water permeability. As a result, the water purifier can
improve both ability for catching fungi and particles-, and water
permeability.
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Preferable Modes
According to a preferable mode of the present invention, the
water purifier can include a water supplying portion for supplying
water to a room of a container containing a filtering material, and a
water discharging portion for discharging water purified by the
filtering material in the room.
According to a preferable mode of the present invention, there
can be provided a first filtering material and a second filtering
material. The first and second filtering materials can be coaxially
placed. One thing out of the first filtering material and the second
filtering material can be disposed at an outer circumferential side
thereof: another thing out of the first filtering material and the
second filtering material can be disposed at an inner circumferential
side thereof. For said one thing, the average pore diameter is
smaller than that of said another thing. For said one thing, though
ability is sufficient for catching fungi and fine particles, pressure
loss is large per unit time in supplying water, and water permeability
is small. When said one thing is disposed at the outer
circumferential side of the filtering material, the area of
water-supplying surface of said one thing is advantageously
increased, and thereby water permeability is increased, while the
catching ability is increased for fungi and fine particles .
Still, as for said one thing whose average pore diameter is
relatively smaller, the average pore diameter may be 0.1 - 0.5,1. m,
especially 0.2 - 0.3,u m. Here, the pore diameter is not limited to
these ranges. Further, as for said another thing whose average pore
diameter is relatively larger, the average pore diameter may be 0.5 -
3. 05 ,u m, especially 0. 5 - 1. 0 ,(.~ m. Here, the pore diameter is not
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limited to these ranges.
According to a preferable mode of the present invention, the
filtering material can have a cylindrical shape, and it can be
provided with an electrode terminal for applying voltage in a radius
direction of the filtering material. This case is advantageous in
applying voltage the whole filtering material for disinfecting fungi
caught in the pore of the filtering material .
According to a preferable mode of the present invention, the
first filtering material and the second filtering material can have a
cylindrical shape, and the both can be coaxially placed in a unit. In
this case, the first filtering material and the second filtering
material can be integrally connected with each other. Moreover, the
first filtering material and the second filtering material can be
coaxially and independently disposed. This case can be obtained by
fitting the first filtering material with the second filtering
material.
According to a preferable mode of the present invention, the
water purifier can include: (1) one electrode selected from a
positive electrode and a negative electrode attached directly or
indirectly to the filtering material; (2j a first electrode terminal
electrically connected with said one electrode: (3) another electrode
selected from a positive electrode and negative electrode attached
directly or indirectly to the container side; and (4) a second
electrode terminal electrically connected with said another
electrode. This case is advantageous in applying voltage to the
filtering material for electrically disinfecting fungi caught in the
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pore of the filtering material.
According to a preferable mode of the present invention, the
filtering material can have a cylindrical shape with a hole in which a
cylindrical member is disposed for forming a way communicated with a
water supplying portion or a water discharging member. There can be
an electrode terminal electrically connected with at least one
selected from a positive electrode and a negative electrode. This
case is advantageous in applying voltage to the filtering material
for electrically disinfecting fungi caught in the pore of the
filtering material.
sintered activated carbon blockfilter
According to a preferable mode of the present invention,
there can be provided a sintered activated carbon block filter formed
as the first filtering material and the second filtering material
constituting the filtering material. The sintered activated carbon
block filter ( hereinafter it is sometimes referred to as block
filter) will be explained. The present inventors have discovered a
following process. The process can include operations of: (1)
preparing a starting material formed by mixing a carbon mixture and a
ceramic binder of artificial or natural, the carbon mixture includes
a base activated carbon powder having an average diameter of 35,(.C m
(or above 30 ,(.C m) - 200 ,u m and a super fine activated carbon powder
having an average diameter of 30,(.c m or less; (2) forming a body by
pressing the starting material; and (3) sintering the body to form a
sintered activated block filter having a plurality of the pores.
The sintered activated block filter produced by the above
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mentioned process is effective: for improving ability for catching
fungi such as viruses; for lowering a pore diameter because of
increasing the amount of the super fine activated carbon powder; and
for ensuring the amount of penetrating water per unit time because of
mixing the base activated carbon powder whose average diameter is
large in addition to the super fine activated carbon powder in such a
manner that a practical water permeability is acquired. A principal
reason of improving ability for catching fungi such as viruses is as
follows : the activated carbon powder such as the super fine activated
carbon powder having ability for catching fungi such as viruses is
frequently exposed to a penetrating minute water-path formed in the
sintered activated carbon block filter. In particular, it is assumed
that the super fine activated carbon powder forms a site for adsorbing
fungi such as viruses having a tendency to be negatively charged.
Further, for improving- ability for catching fungi such as
viruses and for achieving a practical water permeability, the present
inventors have discovered following effective matters: (1) a
proportional weight rate is effective between the carbon mixture and
the ceramic binder; and (2) it is preferable that the amount of the
carbon mixture is increased and that the amount of the ceramic binder
of artificial or natural ceramic binder is decreased. Since the
binder has a tendency to cover the surface of activated carbon powder
particles, the activated carbon has a tendency to be hardly exposed to
the penetrating minute water-path formed in the sintered activated
carbon filter. So, when the amount of the ceramic binder is
decreased, the activated carbon powder such as the super fine
activated carbon powder is easy to be exposed to the penetrating
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CA 02396510 2002-07-30
minute water-path formed in the sintered activated carbon block
filter.
Moreover, the present inventors have also discovered the
effect that fungi such as viruses are disinfected by supplying
boiling water to the sintered activated carbon block filter. Namely,
when the artificial or natural ceramic binder is used; the sintered
activated carbon block filter does not generate a thermal problem in
the case where boiling water penetrates the sintered activated carbon
block filter. This effect is different from resin binder.
According to a preferable process of the present invention,
the process can include features of: (1) preparing a starting
material by mixing a carbon mixture and a ceramic binder of artificial
or natural, the carbon mixture is formed by mixing a base activated
carbon powder having an average diameter of 35 ,u m (or above 30 ,u m) -
200,C.~ m with a super fine activated carbon powder having an average
diameter of 30 ,(.C m or less; (2) setting the amount of the ceramic
binder to be 50 weight ~ or less, and setting the amount of the carbon
mixture to be ~0 weight o or more, when the total amount of the carbon
mixture and the ceramic binder is set to be 100 weight ~~ (4) forming a
body by pressing the starting material; and (5) sintering the body to
form the sintered activated block filter having a plurality of the
pores.
The sintered activated block filter produced by the above
mentioned process is effective: (1) for improving ability for
catching fungi such as viruses; (2) for decreasing a pore diameter
because of increasing the amount of the super fine activated carbon
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powder; and (3) for increasing the amount of penetrating water per
unit time because of mixing of the super fine activated carbon powder
and the base activated carbon powder whose average diameter is large
so as to obtain a practical water permeability
According to a preferable mode of the present invention,
basic designing ideas can be set as the following matters of [1]-[3]
in the sintered activated carbon block filter.
[1]
It is effective that to add a super fine activated carbon
powder having an average diameter of 30 ,u m or less, in addition to a
base activated carbon powder having a large average diameter. The
super fine activated carbon powder can be easily exposed with high
frequency to the penetrating minute water-path formed in the sintered
activated carbon block filter. The super fine activated carbon powder
can be preferable in a diameter of 30 ,u m or less - a . g. , a diameter of
20 ,u m or less . So, when the super fine activated carbon powder is 100
weight $, particles of 1-20,(.C m diameter can be 80 weight o or more,
and particles of below 1,u m diameter can be 20 weight ~ or less.
Still, the base activated carbon powder is effective for increasing
strength of the sintered activated carbon block filter, in ensuring
water permeability per unit time, and in suppressing the surplus
lowering of the pore diameter.
[2]
It is known that resin binder is considerably located in the
negative side in the electrification column and that resin binder is
electrically charged to a negative state. Also, it is known that
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fungi such as viruses are also electrically charged to a negative
state on technical references. Therefore, it is guessed that the
block filter using resin binder is insufficient in ability for
catching fungi such as the viruses because of electrostatic refusal.
On the other hand, when binder is artificial or natural ceramic
system, influence of electrostatic refusal is suppressed in the block
filter with respect to fungi such as viruses to be negatively charged
- thereby catching or adsorbing ability is ensured for fungi such as
viruses.
[3]
Binder has a tendency to cover the surface of the activated
carbon powder; so, the super fine activated carbon powder is hard to
be exposed to the penetrating minute water-path formed in the
sintered activated carbon block filter because of the binder. Thus,
the amount of the carbon mixture can be preferably higher and the
amount of the ceramic binder can be preferably lower in the starting
material which is formed by mixing the carbon mixture and the ceramic
binder. That is to say, when the total of the carbon mixture and the
ceramic binder is set to be 100 weight ~, the ceramic binder can be
preferably 50 weight °s or less, and the carbon mixture can be
preferably 50 weight ~ or more . When the amount of the ceramic binder
is lowered, it is guessed that the activated carbon powder such as
the super fine activated carbon powder is easy to exposed with high
frequency to a penetrating minute water-path formed in the block
filter.
By the above mentioned matters of [1] - [3], catching and
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adsorbing abilities are improved in the water purifier. Especially,
it is effective for catching fungi such as viruses. So, it is
possible that the sintered activated carbon block filter efficiently
catch "brevundimonas" having an outer diameter of 0.3 ,u m and a length
of 0.8,01 m - the smallest testing bacteria in Japan. It is possible
that the sintered activated carbon block filter efficiently catches
"bacteriophage MS-2", namely, a substitutional fungus for
polio-virus in U.S.A. This catching ability is obtained both at a
test water pressure of 1.0 kgf/cm2 being used in Japan and at a test
water pressure 60 psi (4.2 kgf/cm2) being used in U.S.A. Still,
estimating tests generally can use substitutional fungi of
"bacteriophage MS-2" instead of pathogenic polio-viruses.
According to a preferable mode of the present invention,
basic designing ideas can additionally be set as the following
matters of [4] and [5] in producing the sintered activated carbon
block filter.
[4]
It is desirable that sintering temperature can be set to be
1200 °C or less ( generally 950 - 1200 °C ) . This can prevent
the pore
of the sintered activated carbon block filter from shrinking
superfluously in sintering so as to suppress deterioration of
catching or adsorbing ability. Sintering time is varied depending on
size of the block filter and sintering temperature - for example from
30 minutes to 50 hours .
[5]
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It is preferable that compacting pressure increases for
pressing the starting material. Compacting pressure may be for
example lMPa. When the starting material is granulated, an increase
of compacting pressure allows the contacting surfaces of granules to
be crushed to advantageously lower the pore diameter.
Combining the above mentioned matters of [ 1 ] - [ 3 ] and the above
mentioned matters of [4] [5] may be further effective in forming an
ideal pore diameter of the sintered activated carbon block filter.
According to a preferable mode of the present invention, in
the sintered activated carbon block filter used_as a filtering
material of the water purifier, when the amount of the super fine
activated carbon is superfluously larger in the carbon mixture, the
base activated carbon powder is insufficient in amount, and the
sintered activated carbon block filter becomes inferior to be
insufficient in strength. When the amount of the super fine activated
carbon powder is superfluously smaller in the carbon mixture,
insufficient pores are formed. According to the block filter ( said
one thing ), a ratio of super fine activated carbon powder / base
activated carbon powder car_ be preferable in the range 0.1 - 0.8 by
weight ratio. In particular, in the range 0.2 - 0.5, in the range
0.25 - 0.40, or in the range 0.25 - 0.35.
When the average pore diameter of the block filter is
superfluously larger, catching or adsorbing ability is lowered, while
the amount of penetrating water is ensured per unit time. When the
average pore diameter of the block filter is superfluously smaller,
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the amount of penetrating water is lowered per unit time, while
catching or adsorbing ability is ensured. According to a preferable
mode of the block filter, the most frequency peak of pore diameter can
exist within 10,u m or less in a distribution of the pores. In this
case, when the pore volume is set to be 100 volume ~, the pore
exceeding 10 ,cc m can be set below 20 volume ~, below 10 volume ~, below
volume ~, or 0 volume ~ .
According to a preferable mode of the block filter - in
particular, according to said one thing in which average pore
diameter and water permeability are relatively smaller - the total
amount of the ceramic binder and the carbon mixture are set to be 100
weight o, a lower limit of the amount of the super fine activated
carbon powder can be preferably, over 8 weight ~, and over 14 weight ~.
For example, the lower limit may be over 10 weight ~, over 15 weight
over 20 weight ~, or over 30 weight $ . The upper limit of the amount
of the super fine activated carbon powder may be below 40 weight
This is advantageous in lowering average pore diameter.
According to a preferable made of the block filter - in
particular, according to said one thing in which average pore
diameter and water permeability are relatively smaller - when the
carbon mixture and the ceramic binder are set to be 100 weight ~, the
amount of the binder can be preferably set to 30 - 60 weight $, 30 - 50
weight g, 30 - 48 weight ~, or 30 - 45 weight ~ . The binder can
preferably include artificial or natural ceramic binder -- at least
one of alumina component and silica component is mainly contained.
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According to a preferable mode of the block filter, the most
frequency peak exists in 10 ,cc m or less in the pore distribution of the
block filter. Also, when the pore volume is set to be 100 volume o, the
amount of the pores of 2.5 ,C.c m or less can be set to over 40 volume o,
or over 50 volume ~, and the pore exceeding 8 ,u m can be set to below 30
volume ~. This is advantageous in lowing the pore diameter.
According to a preferable mode of the block filter - in
particular, according to said one thing in which average pore
diameter and water permeability are relatively smaller - it is
preferable that the artificial or natural ceramic binder is smaller
in particle diameter. Fine particle of the binder powder is effective
for decreasing pore diameter of the block filter. The artificial or
natural ceramic binder is preferable 150 ,(.~ m or less in particle
average diameter. The binder can be especially below 50 ,c.~ m, below 30
,u m, below 10 ,u m, and below 5 ,u m in particle average diameter.
According to a preferable mode of the block filter, when the
binder of artificial or natural ceramic system is set to be 100 weight
$, it is preferable that the minute particles having a diameter of 5 ,c,C
m or less can be preferably over 30 weight ~ -- in particular over 40
weight ~, over 50 weight ~, or over 60 weight $ . When the binder of the
artificial or natural ceramic system is set to be 100 weight o, it is
preferable that the minute particles having a diameter of 5,u m or
less can be over 70 weight o, -- it is preferable that the minute
particles having a diameter 1 ,ct m or less can be over 30 weight $ .
According to a preferable mode of the block filter, the amount
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of the binder of artificial or natural system can be smaller than that
of carbon mixture. This case is advantageous in lowering the pore
diameter of the block filter. When the proportion of the super fine
activated carbon powder is abounding, crack problem may be sometimes
generated in the block filter. However, when the particles of the
ceramic binder is lowered in diameter, the block filter is ensured in
strength to effectively suppress the crack problem.
According to a process technique of a preferable block filter,
average particle size is larger in the base activated carbon powder
for ensuring both strength and water permeability of the block
filter. Therefore, when the base activated carbon powder is set to be
100 weight o, particles of 35 - 200 ,CC m, or particles of 30 - 200 ,tt m,
can be set to 10 - 70 weight ~. The super fine activated carbon powder
has a smaller average diameter in comparison with the base activated
carbon powder, and it has the particles having a diameter of 30 ,u m or
less - especially a diameter of 20,u m or less. For the super fine
activated carbon powder, when the super fine activated carbon powder
is set to be 100 weight ~, particles of 1 - 20 ,u m can be set over 80
weight o, and particles of under 1 ,u m can be set below 20 weight ~.
However, a proportional rate is not limited to this. The super fine
activated carbon powder is advantageous for lowering the pore
diameter of the block filter, while generating a somewhat tendency to
decrease strength of the block filter.
According to a preferable process technique of the block
filter, compacting pressure can be set over 1.0 MPa for pressing the
starting material. In this case, it is advantageous to lower pore
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diameter by crushing the contacting surface of the carbon powder
granules, when the starting material has a granular shape. Compacting
pressure can be set over 1.2 MPa or 1.5 MPa. An upper limit of
compacting pressure, depending on a pressing machine, can be set for
example 2.0 MPa, 4.0 MPa, or 5.0 MPa.
In pressing the starting material formed by mixing the carbon
mixture with the ceramic binder, since the surface of the activated
carbon powder is covered with the ceramic binder, the activated
surface area being formed in the activated carbon powder is easy to be
decreased. So, according to a preferable process technique, since a
proportion of the binder is set to be relatively smaller, the
activated surface area of the activated carbon powder is easy to be
exposed to the penetrating minute water-path formed in the block
filter. Though the sintered activated carbon block filter, including
the super fine activated carbon powder, is excellent in catching
fungi such as viruses, it exhibits high pressure loss in supplying
water to lower the water permeability.
Still, the above mentioned description on the sintered
activated carbon block filter is preferably applied to the sintered
activated carbon block filter whose average pore diameter is
relatively smaller and whose water permeability is relatively
smaller. Also, the above mentioned description on the sintered
activated carbon block filter can sometimes be applied. on request,
to the sintered activated carbon block filter whose average pore
diameter is relatively larger and whose water permeability is
relatively larger.
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BRIEF DESCRIPTION OF THE DRAWING
A more complete appreciation of the present invention and many
of its advantages will be readily obtained as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawing and detailed
specification, all of which forms a part of the disclosure:
Figure 1 is a graph which shows a distribution of the particle
size of a super fine activated carbon powder;
Figure 2 is a graph which shows a distribution of the particle
size of a carbon mixture in which a base activated carbon powder is
mixed with, the super fine activated carbon powder;
Figure 3 is a graph which shows a distribution of the particle
size of a carbon mixture concerning comparative product;
Figure 4 is a photomicrography ( magnification: x1000 ) of a
block filter concerning invention product No. 1;
Figure 5 is a photomicrography ( magnification: x1000 ) of a
blockfilter concerning a comparative product;
Figure 6 is a graph which shows a pore distribution of the
block filter concerning invention product No. 1;
Figure 7 is a graph which shows a pore distribution of the
block filter concerning the comparative product;
Figure 8 is a sectional view of a water purifier concerning
embodiment 1, having a filtering material formed of an outside
filtering material concerning the invention product and an inside
filtering material concerning the comparative product
Figure 9 is a sectional view of a water purifier concerning
embodiment 2, having a filtering material formed of an outside
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filtering material concerning the invention product and an inside
filtering material concerning the comparative product; and
Figure 10 is a sectional view of a water purifier concerning
embodiment 3, having a filtering material formed of an inside
filtering material concerning the invention product and an outside
filtering material concerning the comparative product:
Figure 11 is a sectional view of a water purifier concerning
embodiment 4 having a filtering material formed of the invention
product; and
Figure 12 is a sectional view of a water purifier concerning
embodiment 5 having a filtering material formed of the invention
product.
DETAILED DESCRIPTION OF THE P~tEF'ERRED EMBODIMENTS
Embodiments will be explained based on the accompanying
figures . Firstly, manufacturing of a sintered activated carbon block
filter constituting the filtering material will hereinafter be
explained. In the super fine activated carbon powder used in the
present embodiment, there are mostly occupied particles having a size
of 20 ,u m or less. Figure 1 shows a particle size distribution of the
super fine activated carbon powder. For the super fine activated
carbon powder, as shown in Figure 1, the particle diameter is set
within 25 ,(.L m, and the particles having 20 ,u m or less occupies 99. 80
weight ~. For the super fine activated carbon powder, the most
frequency region is set in the range 4.47-13.25,cL m, and a median
diameter is set in 6-7,1.c m. The base activated carbon powder being
used in the present embodiment has an average particle diameter of
30-100 ,u m.
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Figure 2 shows a particle diameter distribution of the carbon
mixture, concerning invention product No. 1, in which the base
activated carbon powder is mixed with the super fine activated carbon
powder. Figure 2 indicates that the carbon mixture considerably
contains the fine activated carbon powder having a diameter of 30 ,tc m
or less, when the whole of the carbon mixture is set to be 100 weight ~.
So, when the base activated carbon powder is set to be 100 weight ~,
the particles having a diameter of 35-200 ,fit m occupies 10-70 weight ~.
Figure 3 shows the particle diameter distribution of carbon
mixture concerning the comparative product. Figure 3 indicates that
the carbon mixture scarcely containing a super fine activated carbon
powder having a diameter of 30 ,(.c m or less in the comparative product,
when the whole of the carbon mixture is set at 100 weight o .
The ceramic binder used in the present embodiment is
alumina-silica system (alumina: 40-70 weight ~, silica: 30-60 weight
o ) having a diameter of 150,u m or less. That is to say, when the
ceramic binder is set to be 100 weight $, 80 weight o of the ceramic
binder is the super fine particle having a diameter of about 5 ,u m or
less.
The present inventors have decided a mixing proportion of the
ceramic binder, the base activated carbon powder, and the super fine
activated carbon powder, shown in Table 1, for forming the starting
material concerning invention product No. 1. In this case, the
present inventors fully mixed the starting material by a mixer for
mixing the activated carbon powder and the binder. After mixing the
starting material by the mixer for 5 minutes, the present inventors
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sprayed water to the starting material, and stopped the mixing
operation after 5 seconds. The produced particles have a small
diameter, and they contain a small amount of moisture. If the
produced particles scarcely contain an amount of moisture, the
particles insufficiently combine with each other so as to form coarse
pores. So, it is important to increase an amount of moisture in the
starting material. In view of this, the present inventors provided a
room moisturized by a high-pressure atomizer for setting a
supersaturated humidity condition, kept the staring material in the
room for 3 days, and thereby exceeded 50~ in the amount of water of the
starting material.
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- 22 -
CA 02396510 2002-07-30
Using a hydraulic pressing machine, the present inventors
pressed the aggregate of the starting material having a granular
shape at a pressure of 1.5 MPa to form a body having a cylinder shape
having an outer diameter of 129 mm, an inner diameter of 29 mm, and a
height of 200 mm. Afterwards, the present inventors dried the body by
a hot wind, fired the body in a nitrogen atmosphere at the maximum of
temperature 1195 °C by a continuous tunnel kiln having a transit time
of 10 hours, and thereby produced a sintered activated carbon block
filter concerning invention product No. 1 shown in Table 1 .
In addition, based on conditions shown in Table 1, the present
inventors prepared a starting material concerning invention product
No. 2 by a similar procedure to form a block filter concerning
invention product No. 2. This case uses the above mentioned base
activated carbon powder, the above mentioned super fine activated
carbon powder, and the above mentioned binder. Based on conditions
shown in Table 1, the present inventors respectively prepared each of
starting material concerning invention product Nos. 3-5 by a similar
procedure so as to form each of block filters concerning invention
product Nos. 3-5. Also, the present inventors produced the comparative
product.
Table 1 shows physical properties of the block filters. As
shown in Table l, in invention product No. 1, the amount of binder is
48~ by weight ratio, being below the amount of carbon mixture
(52~=40$+12~). In invention product No. 2, the amount of binder is
35.4 by weight ratio, being below the amount of carbon mixture
(64~=54~+l00) . In invention product No. 3, the amount of binder is as
- 23 -
CA 02396510 2002-07-30
much as 58~. In invention product No. 4, the amount of binder is as
much as 60~. Invention product No. 5 contains binder as little as
30$, including the super fine activated carbon powder, and not
including the base activated carbon powder. The comparative product
includes the base activated carbon powder, not including the super
fine activated carbon powder.
When a proportion of the super fine activated carbon powder is
abounding, the sintered activated carbon block filter lowers in
strength to be broken. However, according to the present embodiment,
as above mentioned, since the particles of the ceramic binder,
artificial binder or natural binder, is set to be small in grain size,
the sintered activated carbon block filter is advantageously improved
in strength so as to reduce a pore diameter in the sintered activated
carbon block filter.
Figure 4 shows a photomicrography ( test piece : No. 11-3 ) of
the sintered activated carbon block filter concerning invention
product No. 1. Figure 5 shows a photomicrography ( test piece : No.
2W-3 ) of the sintered activated carbon block filter concerning the
comparative product. In Figures 4 and 5, a blackish area shows the
activated carbon powder, and a whitish area shows the ceramic based
binder. As shown in Figure 4, in invention product No. 1, since the
blackish area is large, it is understood that the activated carbon
powder such as the super fine activated carbon powder is frequently
exposed to a penetrating minute water-path formed in the block
filter. So, invention product No. 1 is advantageously improved in
catching and adsorbing abilities. Still, Figure 4 suggests that the
- 24 -
CA 02396510 2002-07-30
blackish area is about 70-85 area ~ when the whole visual field shown
in Figure 4 is set at 100 area $ . As shown in Figure 5, in the
comparative product, since the whitish area is large, it is
understood that the binder is frequently exposed to a penetrating
minute water-path formed in the block filtsr and that the activated
carbon powder is scarcely exposed to the penetrating minute
water-path. Such comparative product is not effective in catching
and adsorbing abilities.
Figure 6 shows a distribution of pore diameter of the sintered
activated carbon block filter concerning invention product No. 1.
This distribution is measured by mercury inserting method. As shown
in Figure 6, invention product No. 1 with a small pore diameter does
not substantially contain the pores exceeding 10 ,u. m, and it is
sufficient in pore diameter. Invention product No. 2 indicates the
same pore-distribution as invention product No. 1. That is to say,
for the sintered activated carbon block filters concerning invention
product Nos. 1 and 2, when the pore volume is set at 100 volume $, the
pores having a pore diameter of 2.5 ,lc m or less are set over 40 volume
or more, and the pore having a pore diameter exceeding 8,i.L m is
fewer. This result allows the amount of pare volume to become large
so as to increase an amount of water discharged from the sintered
activated carbon block filter. Also, this result allows the pore
diameter to be small to effectively catch viruses .
Figure 7 shows a distribution of pore diameter of the sintered
activated carbon block filter concerning the comparative product. In
the sintered activated carbon blockfilter concerning the comparative
- 25 -
CA 02396510 2002-07-30
product, the pore diameter is coarse, and the coarse pore of exceeding
20 ,u m is large in volume o . As shown in Figure 7, in the comparative
product, the minute pores of 2. 5 ,(.t m or less is relatively abounding,
a frequency peak is near 20 ,u m in diameter, and coarse pores of about
100 ,u m are considerably existed. The existence of coarse pores over
20,CC m can increase the amount of penetrating water per unit time,
while it is not sufficient in capture or absorption ability of the
sintered activated carbon blockfilter.
As shown in Table 1, invention product Nos . 1 and 2 are 39-42$
in the porosity rate of the block filter. In the meantime, the
comparative product not including the super fine activated carbon
powder porosity is as little as 37~ in the porosity rate of the block
filter. For compressive strength, invention product Nos. 1-4 are
sufficient. However, compressive strength is considerably lowered
in invention product No. 5 not including the base activated carbon
powder. Compressive strength is higher in the comparative product
not including the super fine activated carbon powder. A
chloroform-removing ratio is measured by inserting starting water
dissolving chloroform having a concentration of 40ppb into the block
filter. For the chloroform-removing ratio, invention product Nos. 1
and 2 are sufficient in comparison with invention product Nos. 3, 4
and the comparative product.
test for removing dust particle
The present inventors carried out a test by inserting air
including dust particles having a diameter of approximately 0 .3 ,(,L m
into the block filter. Dust particles held in the air are measured
- 26 -
CA 02396510 2002-07-30
per air of 1 liter by a laser beam. For measuring the number of dust
particles, which penetrate the block filter, having an average
diameter of 0 . 3 ,c.~ m, as shown in Table 1, invention product No . 1
exhibits below ten (10) , so it is sufficient. Invention product No. 2
exhibits the range from forty to fifty (40-50), so it is sufficient.
Invention product No. 3 exhibits six hundred (600), so it is good.
Invention product No. 4 exhibits twenty (20) , so it is sufficient.
Invention product No. 5 is not measured because of insufficient
strength. The comparative product exhibits over five thousand
(5,000), so it is insufficient. According to this test, in air of 1
liter before penetrating the block filter, the number of dust
particles having a diameter of 0.3 ,u m are measured on the average of
forty-five thousand (45,000). Thus, invention product Nos. l, 2, 3,
and 4 are good in catching the fine particles in comparison with the
comparative product. In particular, invention product Nos. 1 and 2,
having a small amount of binder, are excellent in catching the fine
particles in comparison with invention product Nos. 3, 4, and the
comparative product.
penetrating test of "brevundimonas fungus"
The present inventors also carried out a test in which
"brevundimonas fungus" having an outer diameter of 0.3,u m and a
length of 0.8 ,t.C m penetrates the block filter. In invention product
No. 1, though an average pore diameter of the block filter exhibits
0.40,(.0 m to be a comparative large, the number of "brevundimonas
fungi" which penetrate the block filter is 0 - so, catching ability
is excellent in invention product No. 1. In invention product No. 2,
- 27 -
CA 02396510 2002-07-30
the number of "brevundimonas fungi" which penetrate the block filter
is 510 /ml/ 3,500,000 - so, catching ability is sufficient. The
terms of "510 / ml/ 3,500,000" means the number of "brevundimonas
fungi" which penetrate the block filter is five hundred and ten (510)
in the case where water is used including three million five hundred
thousand (3,500,000) of "brevundimonas fungi" per water of lml
(milliliter) . The invention product No. 4 is three hundred and fifty,
350 /ml/ 1, 200, 000 - so, catching ability is good.
In the comparative product whose water-discharging ability is
sufficient and whose catching ability is not always sufficient, the
number of "brevundimonas fungi", which penetrate the block filter,
exceeds one thousand (1, 000) - so, catching ability is insufficient.
Therefore, invention product Nos . 1-4 have a superiority in catching
ability in comparison with the comparative product. In particular,
invention product Nos. 1 and 2 can provide the sintered activated
carbon block filter with bacteria-proof in comparison with the
comparative product. - so, invention product No. 1 is very
sufficient in catching ability.
test for removing substitutional fungi for polio viruses
The present inventors carried out a test for removing
substitutional fungi for polio viruses. Since there is seldom a
crisis of poliomyelitis, Japan does not impose legal controls in
removing polio viruses . However, advanced countries of water supply,
such as U.S.A, impose legal controls in removing polio viruses as a
standard of purified water. In view of this situation, half of water
purifiers used in home of U.S.A. are a reverse osmosis membrane type
- 28 -
CA 02396510 2002-07-30
having a pore diameter of 10 ~ (angstrom) - this is defense for polio
viruses in each home. The polio virus has a spherical shape of
25-35nm ( 250-350 ~ : 0. 025-0.035 ,cc m ) in outer diameter, and it has
a plurality of protrusions in circumference thereof . The test using
polio viruses is very dangerous. Then, U.S.A. allows "bacteriophage
MS-2" with an almost equal size and shape as a substitutional fungus
in medical fields and the like. So, the present inventors carried out
a water penetrating test using "bacteriophage MS-2". The starting
water before penetration includes the number of MS-2 of 1, 000, 000/m1.
Table 1 shows test results. As shown in Table 1, invention
product No . 1 do not allow penetration of "bacteriophage MS-2". It is
appreciated that the block filter concerning invention product No. 1
can effectively catch polio viruses or "bacteriophage MS-2". A
plenty of activated carbon powders such as super fine activated
carbon powders are frequently exposed to the minute water-path for
penetrating water in the block filter concerning invention product
No. 1, as shown in Figure 4. Water pressure is set at 30 psi (2.1
kgf/cm2) and 60 psi (4.2 kgf/cm2), respectively in this test.
Especially, the water pressure of 60 psi is similar to the average
water pressure in U.S.A. Invention product No. 4 has a small average
pore diameter of 0.24 ,c..E m in the above block filter, being anticipated
in catching "bacteriophage MS-2". Invention product No. 4 do not
allow the penetration of :"bacteriophage MS-2" at a water pressure of
30 psi (2.1 kgf/cm2). Also, invention product No. 4 reduces the
penetration number of "bacteriophage MS-2" to below 50 at a water
pressure of 60 psi (4.2 kgf/cm2)
- 29 -
CA 02396510 2002-07-30
Incidentally, the compressed activated carbon powder with
polyethylene binder is generally used in U.S.A., and the hollow fiber
membrane of the polypropylene is generally used in Japan. It is known
that they can remove soluble lead and lead ions. Also, it is known
that material of polyethylene and polypropylene become negatively to
generate negative static electricity having a voltage tens of
thousand volts in water. So, lead ions having electrically positive
charges is easy to be adhered to polyethylene or polypropylene by
electrostatic absorption.
However, no reports indicate that viruses such as polio viruses
are caught by the block filter having polyethylene binder. This is
because the virus having negative charges is seldom adhered to
polyethylene cr polypropylene to be negatively charged. There are
some reports of catching fungi - "brevundimonas" with a diameter of
0.3 ,u m, a smallest diameter to be caught by pores, "escherichia coli"
with a diameter of 0. 65 ,(.~ m, "protozoans" with several tens ,(.C m, and
fungi with several tens ,u m.
It is known that "bacteriophage MS-2" for working as a
substitutional fungus for polio virus is totally composed of capsid
protein of "VP1-VP4", and it is covered with "VP1-VP3" to exhibit an
electrically negative charge because of carboxyl group. Therefore,
it is estimated that viruses with an electrically negative charge is
not caught by polyethylene binder because of electrostatic refusal -
polyethylene binder whose surface is to be an electrically negative
charge.
On other hand, on using conditions of the block filter of water
purifiers, it is appreciated that the ceramic binder such as the
artificial ceramic binder or natural ceramic binder is not charged in
- 30 -
CA 02396510 2002-07-30
an electrically negative or positive state. Therefore, it is
appreciated that the block filter using the ceramic binder can catch
viruses having an electrically negative charge without generating an
electrostatic refusal, unlike the polyethylene binder which is easy
to become negatively.
Conventionally, some references disclose that methods using
the flocculant of electrically positive charge - e.g., "water
petrifying technology" (published by Gihoudou company, on page 45,
"item of condensation and flock" ) as a technology for removing
viruses having a negative charge in a water supplying field. Also, it
is known that virus become electrically negative charge in various
quarters.
Since invention product No. 5 extremely reduces a proportion
of the ceramic binder and do not include the base activated carbon
powder, it has a porosity rate of 39.1 °~. Invention product No. 5,
however, is insufficient in sintered strength so that pores quickly
collapse because of pressure of penetrating water. Further, the
present inventors individually carried out the operations of: (1)
producing test specimens at a compacting pressure of 3. 1 MPa, 2. 5 MPa,
and 0.8 MPa, respectively, not be shown in Table 1, with selecting the
same composition as invention product No. 5; and (2) measuring pore
distributions of the sintered activated carbon block filters of test
specimens. When the base activated carbon powder is not mixed and
when the binder is as low as about 30~, even if the compacting pressure
is increased, the pores are quickly collapsed. So, invention product
No . 5 is applicable in the case where the pressure of the penetrating
- 31 -
CA 02396510 2002-07-30
water is small, or the case where a collapse of pores do not affect a
practical usage.
Also, the comparative product includes the base activated
carbon powder, never including the super fine activated carbon
powder. So, a rate of activated carbon powder is 50 weight ~ and the
alumina binder is 50 weight ~ in the starting material of the
comparative product. Accordingly, the block filter concerning the
comparative product is considerably varied in pore diameter and in
the pore distribution of the block filter, depending on compacting
pressure. Namely, it has a tendency in which the porosity rate of the
block filter is decreased with increasing compacting pressure.
Keeping a coarse pores, the block filter concerning the comparative
product considerably includes bulky pores having a diameter from 2.5
,~t m to several tens ,~t m. Accordingly, it is appreciated that mixing
of the fine activated carbon powder such as the super fine activated
carbon powder is effective in lowering the pore diameter of the block
filter.
As above mentioned, when the amount of ceramic binder is
little in the starting material, the increasing of compacting
pressure is not effective in lowering the pore diameter of the
sintered activated carbon block filter - the increasing of the
amount of the super fine activated carbon powder is effective in
lowering the pore diameter.
The present embodiment selects silica-alumina based binder as
a ceramic binder. The present embodiment can select at least one of
- 32 -
CA 02396510 2002-07-30
silica, magnesia, clay based binder, etc., having binding ability.
The present embodiment can use them with the silica-alumina based
binder or without the silica-alumina based binder.
Figure 8 shows a water purifier concerning embodiment 1.
Filtering material 1 provided with the water purifier is formed of a
block filter. The filtering material 1 has a vertical cylindrical
shape, having an outer diameter of 122mm, an inner diameter of 35mm,
and a height of 186mm. The filtering material 1 has an inner
circumference surface 140 forming a hole3 formed along an axial
direction, a vertical direction, in a central portion thereof. There
are fixed caps 4, 4 made of resin for preventing a collapse of axial end
surfaces of the filtering material 1. The caps 4,4 are fixed at the
filtering material 1 with adhesive such as silicon adhesive. Since
the caps 4, 4 cc,ver the axial end surfaces of the filtering material 1,
the caps 4, 4 prevent water from flowing from the axial end surface of
the filtering material 1 in such a manner that water penetrates the
filtering material 1 in a radius direction. Especially, this
advantageously allows water to penetrate the filtering material 1
from the outer circumferential portion of the filtering material 1 to
the central portion of the filtering material 1 .
As shown in Figure 8, the water purifier includes: (1) a
cylindrical container 101 having a room 100 and formed of metal
material such as stainless steel to exhibit electrical conductivity;
(2) the filtering material 1 having water permeability and contained
vertically in the room 100 of the container 101; (3) an inner cylinder
2 for working as a cylindrical member and disposed vertically in the
hole 3 of the filtering material 1; (4) a pedestal 102 formed of
- 33 -
CA 02396510 2002-07-30
material not having an electrical conductivity (for example resin )
and disposed at the bottom of the container 101; (5) a lid 103 formed
of material having an electrical conductivity, for example metal such
as stainless steel, and disposed for covering an upper opening of the
container 101; ( 6) , a water supplying portion 104 disposed at an outer
circumferential portion of the container 101 for supplying water to
the room 100 of the container 101; (7) a water discharging portion
105 disposed at the central portion of the upper portion of the
container 101 and communicated with the room 100 and the inner
cylinder 2; (8) several first electrodes 107 having a projection
shape formed of material having an electrical conductivity, for
example metal such as titanium alloy or copper alloy, and inserted
into the bottom of the filtering material l; (9) a conductive member
108 electrically connected with the first electrode 107; (10) an
electrode terminal 109 ( a first electrode terminal ) electrically
connected with the first electrode 107 by way of the conductive member
108; (11) a second electrode 110 held on the pedestal 102 and
electrically connected with the lower portion of the inner cylinder
2; and (12) an electrode terminal 111 ( a second electrode terminal)
electrically connected with the second electrode 110 and attached at
the container 101 by way of the inner cylinder 2 and the lid 103 .
The inner cylinder 2 has a plurality of openings 2c in the
circumferrencial wall thereof for inducing water. The conductive
member 108 has a ring shape and is disposed at the bottom surface of
the filtering material 1. The inner cylinder 2 is formed of
conductive material, for example metal. The container 101 has a
cylindrical shape whose axial line is vertically disposed. The lid
- 34 -
CA 02396510 2002-07-30
103 closes the upper opening of the container 101. The lid 103 is
electrically connected with the outer circumferential portion of the
container 101 and the inner cylinder 2. So, the outer circumferential
portion of the container 101 and the inner cylinder 2 will be in the
same electrical pole. The inner cylinder 2 has a way 2a disposed
vertically and communicated with the water discharging portion 105.
As shown in Figure 8, the filtering material 1, being placed in
the water purifier, has a cylindrical shape. The filtering material 1
is formed of both of: an inside filtering material 10A (said another
thing) having a cylindrical shape disposed inside; and an outside
filtering material lOB (said one thing) having a cylindrical shape
coaxially disposed outside. The outside filtering material lOB (said
orie thing) is coaxially disposed with the inside filtering material
10A (said another thing). The outside filtering material lOB (said
one thing)is composed by a fine pore layer formed by a sinter
activated carbon block filter of invention product No. 1 or 2
including the super fine activated carbon powder. As above mentioned,
in invention product No. 1 or 2, ability is excellent for catching
fungi such as viruses, pressure loss is high in supplying water, and
the amount of penetrating water is small per unit time. Then, for
compensating water permeability, the inside filtering material 10A
(said another thing) does not include the super fine activated carbon
powder, and it is composed by a coarse pore layer formed of the
comparative product ( shown in Table 1) in which the average pore
diameter is coarse. For the comparative product, ability is not
always sufficient for catching fungi such as viruses, pressure loss
is lower in supplying water, and the amount of penetrating water is
- 35 -
CA 02396510 2002-07-30
large per unit time. Therefore, the water purifier can increase the
amount of penetrating water per unit time, while ensuring the ability
for catching fungi such as viruses .
According to the water purifier, the inside filtering material
10A and the outside filtering material lOB may integrally be formed in
a unit. Also, the inside filtering material 10A may be coaxially
fitted with the outside filtering material 10B.
As above mentioned, since the outside filtering material lOB
(said one thing) formed of invention product No. 1 or 2 is composed of
a fine pore layer, it is smaller in the amount of penetrating water per
unit time. In this respect, the outside filtering material lOB is
large in a radius distance of "r1" between a center line of the
filtering material 1 and the outer surface thereof (shown in Figure
8). So, the outside filtering material lOB is advantageous in
increasing a starting surface of the water-penetrating area of the
filtering material 1 . As a result, the outside filtering material lOB
is large as much as possible in the amount of penetrating water per
time, thereby increasing the amount of purified water in the water
purifier.
The present embodiment forms a clearance 130 having a ring
shape coaxially between an outer circumference surface lm of the
filtering material 1 and an inner circumference surface lOlm of the
container 101. Since the first electrode 107 is set as a positive
electrode: so, the filtering material 1 in which the first electrodes
107 are buried has a positive electrode surface. The second
electrode 110 is set as a negative electrode. Therefore, the inner
- 36 -
CA 02396510 2002-07-30
cylinder 2 formed of the electrical conductive material to be
conducted with the second electrode 110 will become a negative
electrode. The pores are communicated with each other to exhibit
water permeability.
When water is purified by using the water purifier, the
electrode terminal 109 electrically connected with the first
electrode 107 is set in a positive pole, and the electrode terminal
111 electrically connected with the second electrode 110 is set in a
negative pole. In this condition, voltage (far example, voltage of
1-10 volts, 1-5 volts, or 2-3 volts) is applied to the electrode
terminals 109 and 111. The voltage is DC (direct current) voltage.
The filtering material 1 is electrically connected with the first
electrode 107, it will fundamentally become positively. The inner
cylinder 2 are connected with the second electrode 110 will become a
negative electrode. The container 101 is connected with the upper
portion of the inner cylinder 2 by way of the lid 103. So, the
container 101 will become negatively. As a result, voltage is applied
to the filtering material 1 in a radius direction thereof, and voltage
is applied to fungi caught in the pores of the filtering material 1 to
disinfect the fungi. Since voltage is applied to the filtering
material 1 in a radius direction thereof, voltage is advantageously
applied to the whole of the filtering material 1.
In purifying water, water is supplied into the room 100 from
the water supplying portion 104. The water is supplied in the
clearance 130 between the outer circumference surface 1m of the
filtering material 1 and the container 101. Further, the water
- 37 -
CA 02396510 2002-07-30
penetrates the inside of the filtering material 1 in a centripetal
direction exhibiting an arrow direction of "W", a radius direction,
from the outer circumferential surface of filtering material 1 to the
center area thereof. Though a compressive force is generated to the
filtering material 1 in the centripetal direction, a tensile force
can not work to the filtering material 1 . Because the water penetrates
the filtering material 1 in an arrow direction of "W". So, this can
advantageously avoid fracture of the filtering material 1, even if
water pressure is higher.
As shown in Figure 8, since the water discharging portion 105
is disposed at the upper portion of the container 101 to face the
central area of the upper portion of the filtering material 1, the
water can advantageously run in the centripetal direction, the radius
direction, from the outer circumferential surface of filtering
material 1 to the center area thereof .
Water runs in the centripetal direction, the arrow direction
of "W", from the outer circumferential surface of the filtering
material 1 to the center area thereof . So, firstly, water penetrates
the filtering material lOB (said one thing) whose average pore
diameter is relatively smaller and whose water permeability is
relatively smaller per unit time . Secondly, the water penetrates the
filtering material 10A (said another thing) whose average pore
diameter is relatively larger and whose water permeability is
relatively larger per unit time. As a result, fungi, dusts and the
like are effectively caught by the filtering material 10B placed
apart from the water discharging portion 105, thereby keeping the
filtering material 10A clean as much as possible.
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CA 02396510 2002-07-30
The water penetrated the filtering material 1 comes to the hole
3 of the filtering material l, and it flows from the openings 2c of the
inner cylinder 2 disposed in the filtering material 1 to the way 2a of
the inner cylinder 2. The water runs upwards along the way 2a of the
inner cylinder 2, and it is discharged as purified water from the
outlet 105a of the water discharging portion 105 disposed at the upper
portion of the container 101 .
Since voltage is applied, the pore inwall of the filtering
material 1 may exhibit a positive charge. The pore inwall catches or
adsorbs fungi such as superfine viruses having a diameter of 25-35
nanometer (nm) by electrostatic adsorption effect, thereby fixing the
fungi in the pores of the superfine activated carbon powder
constituting the exposed inwall of pores. So, the pore inwall
prevents the fungi from being emitted. This can improve catching and
absorptive abilities of the filtering material 1 .
Still, the above usage shows that the first electrode 107 and
the electrode terminal 109 are positive, and the second electrode 110
and the electrode terminal 111 are negative. Also, it is possible
that the first electrode 107 and the electrode terminal 109 are
negative and the second electrode 110 and electrode terminal 111 are
positive. Such case can apply voltage to the filtering material 1 in
a radius direction to carry out an electrical fungicide .
The above mentioned block filter, whose ability is excellent in
catching viruses, can catch or adsorb viruses and bacteria. However,
there is a problem that fungi such as viruses and bacteria caught in
the inside of the filtering material 1 exists. Therefore, all
components' of the water purifier are formed of material having
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heat-resistance of 90-100°C . Therefore, the water purifier can
periodically be cleaned by supplying boiling water to the water
purifier. It is known that fungi such as viruses and bacteria die
over 75 °C within at least 1 minute . Still, alternating voltage can be
applied to the first electrode 107 and the second electrode 110.
Embodiment 2
Figure 9 shows embodiment 2. A water purifier concerning
embodiment 2 is fundamentally identical with that of embodiment of 1
in structure and effect. The common portion is referred to the common
code. In embodiment 2, a filtering material 1 mounted on the water
purifier includes : ( 1 ) an inside filtering material 10A (said another
thing) having a cylindrical shape and disposed inside: and (2) an
outside filtering material lOB (said one thing) having a cylindrical
shape and disposed coaxially outside for forming in a multiple layer
structure. The outside filtering material lOB (said one thing)is
coaxially disposed with the inside filtering material 10A (said
another thing). The outside filtering material lOB is composed of a
fine pore layer formed by the block filter of invention product No. 1
or 2 including the super fine activated carbon powder: As above
mentioned, for invention product No . 1 or 2, ability is excellent for
catching fungi such as viruses, pressure loss is high in supplying
water, and the amount of penetrating water is small per unit time.
Then, for compensation of water permeability, the inside
filtering material 10A - said another thing - does not include the
super fine activated carbon powder, and it is composed by a coarse
pore diameter layer formed of the comparative product ( shown in Table
1) in which the average pore diameter is large. For the comparative
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product, ability is not excellent for catching fungi such as viruses,
pressure loss is lower, and the amount of penetrating water is large
per unit time. Therefore, the water purifier concerning embodiment 2
can increase the amount of penetrating water per unit time, while
ensuring ability for catching fungi such as viruses. However,
embodiment 2 is not provided with the first electrode 107, and it does
not apply voltage to the filtering material 1. Even when voltage was
not applied to the filtering material 1, electromotive force
naturally generated in water was 250mV and 400 ,u A (micro ampere) by
electroconductive different materials in such a manner that the
filtering material 1 formed by the block filter is electrically
charged in a positive .
Embodiment 3
Figure 10 shows embodiment 3. A water purifier concerning
embodiment 3 is fundamentally identical with that of embodiment 1 in
structure and effect. The common portion is referred to the common
code. As shown in Figure 10, in embodiment 3, a filtering material 1
mounted on the water purifier includes: an inside filtering material
10A (said one thing) having cylindrical shape and disposed inside;
and an outside filtering material lOB (said another thing)having a
cylindrical shape and disposed coaxially outside.
The inside filtering material 10A shown in Figure 10 - said
one thing - is coaxially disposed with the out inside filtering
material 10B. The inside filtering material 10A (said one thing) is
composed of a fine pore layer formed by a block filter of invention
product No. 1 or 2 including the super fine activated carbon powder
and the ceramic binder. Invention product No. 1 or 2 has an excellent
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ability for catching fungi such as viruses. For invention product No.
1 or 2, the average pore diameter is small, pressure loss is high in
supplying water, and the amount of penetrating water is small per unit
time.
Then, for compensation of pressure loss and water
permeability, the outside filtering material 10B shown in Figure 10 -
said another thing - does not include the super fine activated carbon
powder. The outside filtering material 10B shown in Figure 10 (said
another thing)is composed by a coarse pore layer formed of the
comparative product ( shown in Table 1 ) . For the comparative product,
ability is not always excellent for catching fungus such as virus,
pressure loss is lower in supplying water, and the amount of
penetrating water is large per unit time. Therefore, the water
purifier concerning embodiment 3 can increase the amount of
penetrating water per unit time, while ensuring an ability for
catching fungus such as virus . '
The inside filtering material 10A- said one thing - in which
the amount of penetrating water is small per unit time. The wall
thickness of the inside filtering material 10A is shown as "ta" . The
outside filtering material lOB - said another thing - in which the
amount of penetrating water is large per unit time . The wall thickness
of the outside filtering material lOB is shown as "tb" . Here, "ta" is
smaller than "tb". This can ensures the amount of penetrating water
per unit time in the water purifier.
According to the present embodiment, as shown in Figure 10,
water runs in the centripetal direction, the arrow direction of "W",
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from the outer circumferential surface of filtering material 1 to the
center area thereof. So, firstly, the water penetrates the filtering
material lOB whose average pore diameter is relatively large and
whose water permeability is relatively large per unit time. Secondly,
water penetrates the filtering material 10A whose average pore
diameter is relatively small and whose water permeability is relative
small per unit time .
Incidentally, according to the test for penetrating
"brevundimonas", a substitutional fungi for polio viruses, at the
case of a water pressure of 4.2 kgf/cm2, a sufficient catching ability
requires that the wall thickness of the fine pore layer is at least 15
mm. The test result shows that the thickness up to 25 mm in the fine
pore layer correlates closely with the amount of penetrating water.
Further, the wall thickness over 25mm of the fine pore layer hardly
correlates with the amount of penetrating water in a viewpoint of the
relationship between wall-thickness and water permeability.
Also, embodiments 1-3 can allow the operations of: (1)
individually cutting a fine pore layer and a coarse pore layer to be a
different size: and (2) combining with each other in a unit to form the
filtering material 1. Further, embodiments 1-3 can allow the
operations of: (1) preparing one starting material for forming the
fine pore layer and another starting material for forming the coarse
pore layer; (2) inserting said one and another of starting materials
separately into a pressing die-cavity (3) pressing the stating
materials to integrally form the filtering material 1. This method is
advantageous in production. Such case permits a different compounding
rate between the one starting material for forming the fine pore layer
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CA 02396510 2002-07-30
and the another starting material for forming the coarse pore layer.
This may generate differences in a drying contraction quantity, and a
sintering contraction quantity between the fine pore layer and the
coarse pore layer. So, this may require a consideration for
preventing cracks.
Embodiment 4
Figure 11 shows a sectional view of a water purifier concerning
embodiment 4 having a filtering material 1. The water purifier
concerning embodiment 4 is fundamentally identical with that of
embodiment 1 i.nstructure and effect. The common portion is referred
to the common code. As shown in Figure 11, the filtering material 1
mounted on the water purifier includes a cylindrical shape. The
filtering material 1 is composed of a fine pore layer formed by a block
filter of invention product No. 1 or 2 including the super fine
activated carbon powder, the base activated carbon powder, and the
ceramic binder. The ceramic binder is alumina-silica system (alumina:
40-70 weight ~, silica: 30-60 weight ~ ) having a diameter of 150 ,u m
or less. That is to say, when the ceramic binder is set to be 100
weight ~, 80 weight ~ of the ceramic binder is the super fine particle
having a diameter of about 5 ,u m or less. Invention product No. 1 or 2
has an excellent ability for catching fungi such as viruses .
Embodiment 5
Figure 12 shows a sectional view of a water purifier concerning
embodiment 5 having a filtering material 1. The water purifier
concerning embodiment 5 is fundamentally identical with that of
embodiment 2 in structure and effect, not including an electrode. The
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CA 02396510 2002-07-30
common portion is referred to the common code. As shown in Figure 12,
the filtering material 1 mounted on the water purifier includes a
cylindrical shape. The filtering material 1 is composed of a fine pore
layer formed by a block filter of invention product No. 1 or 2
including the super fine activated carbon powder, the base activated
carbon powder, and the ceramic binder. The ceramic binder is
alumina-silica system (alumina: 40-70 weight ~, silica: 30-60 weight
having a diameter of 150,LC m or less. That is to say, when the
ceramic binder is set to be 100 weight ~, 80 weight ~ of the ceramic
binder is the super fine particle having a diameter of about 5 ,u m or
less. Invention product No. 1 or 2 has an excellent ability for
catching fungi such as viruses .
additional remarks
In embodiment 1, the outside filtering material 10B - said
one thing whose average pore diameter is relatively small - is
composed by a block filter of invention product No. 1 or 2 including
the super fine activated carbon powder to exhibit a small diameter
pore. The outside filtering material 10A - said another thing whose
average pore diameter is relatively larger - is composed by a block
filter of the comparative product not including the super fine
activated carbon powder to exhibit a coarse diameter pore.
However, the outside filtering material lOB exhibiting a
small diameter pore can be composed by a block filter of invention
product No. 3 or 4 including the super fine activated carbon powder
and the ceramic binder. In this case, the inside filtering material
exhibiting a large diameter pore is composed by a block filter of the
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CA 02396510 2002-07-30
comparative product not including the super fine activated carbon
powder.
Also, embodiments 1-3 uses the ceramic binder as a binder for
forming the block filter; further, they may sometimes use resin
binder. Embodiments 1-3 uses the filtering material having a
two-layer structure: further, they may sometimes use a filtering
material having a three-layer structure. The size of the filtering
material 1 is not limited within the above mentioned range .
Having now fully described the present invention, it will be
apparent to one of the ordinary skill in the art that many changes and
modifications can be made thereto without departing from the split of
scope of the present invention as set forth herein including the
appended claims.
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