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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device which permits easy delivery of a
sterile water or pharmaceutical liquid used in the fields of medical
treatment, health and hygienics or sanitation, biochemistry, bacteriology,
or in the fields associated with foods and drinks and cosmetics. More
particularly, the present invention is concerned with improvements in a
liquid purifying device which is suitable for delivering or dispensing a
sterile liquid, through an outlet of a container communicating with the
ambient atmsophere, while preventing contamination by microorganisms
passing into the container through the outlet.
2. Discussion of the Prior Art
Various aqueous solutions, pharmaceutical liquids or liquid drugs are used
in the fields of medical treatment, health and hygienics, biochemistry and
bacteriology, for example. Examples of such liquids include pharmaceutical
liquids used in medical institutions such as hospitals, and soaking or
cleaning solutions for contact lenses. The liquids are generally purchased
as accommodated in comparatively large containers, and are dispensed in
desired amounts when needed, for a reltively long period. The containers
have dispenser outlets through which the liquids are delivered. This
arrangement for dispensation of the liquids suffers from contamination of
the liquids by bacteria or microorganisms which may come into the
containers through the liquid delivery outlet.
In view of the above drawback, the assignee of the present application
proposed liquid purifying devices as disclosed in laid-open Publication
Nos. 62-125804 and 62-90706 of unexamined Japanese Patent Application and
unexamined Japanese Utility Model Application, respectively. These devices
use a container for accommodating a liquid, and a micro-porous membrane
disposed in a liquid delivery path. The container is formed of a suitable
elastic material so that the container body is elastically contracted, by
squeezing hand pressure, to deliver the liquid, and is elastically
restored to its original shape upon releasing of the hand pressure. The
micro-porous membrane permits the liquid to flow therethrough but inhibits
passage of bacteria therethrough. In this device, the bacteria contained
in the liquid are removed by the micro-porous membrane provided in the
liquid delivery path, when the liquid is delivered or dispensed from the
container. Accordingly, even the liquid which is contaminated by
microorganisms within the container may be purified so that the liquid as
dispensed may be made sterile.
In the proposed liquid purifying devices, however, the liquid delivery path
or passage for delivering the liquid from the container is held exposed to
the ambient atmosphere. Therefore, the interior of the liquid delivery
passage, and the micro-porous membrane filter disposed therein may be
contaminated by microorganisms introduced through the exposed end of the
passage. The microorganisms may easily enter the liquid delivery passage,
together with a flow of the ambient air into the interior of the container
through the liquid delivery passage, due to a comparatively reduced
pressure within the container, which is developed when the contracted
container is elastically restored to its original shape. Consequently, a
portion of the liquid mass which has been purified by the porous film
filter but has not been delivered may be contaminated by the
microorganisms contained in the air which is sucked into the liquid
delivery passage. Thus, the proposed liquid purifying device is not
satisfactory in its capability of removing microorganisms, and has some
room for improvements.
SUMMARY OF THE INVENTION
The present invention was made in view of the prior art situations
described above. It is accordingly an object of the present invention to
provide a liquid purifying device for dispensing a sterile liquid, which
is simple and compact in construction, and which is suitably protected
against contamination by microorganisms through a liquid delivery passage
exposed to the atmosphere, thereby providing improved liquid purifying
capability.
The above object may be accomplished according to the principle of the
present invention, which provides a liquid purifying device for dispensing
a liquid, comprising: (a) a container having an enclosed interior space in
which a mass of the liquid is stored; (b) first valve means, attached to
the container, for permitting a supply flow of a pressurized gas
therethrough into the interior space of the container to raise a pressure
within the interior space, and for inhibiting a discharge flow of the
pressurized gas and the liquid therethrough out of the interior space; (c)
a liquid delivery path having one end submerged in the mass of the liquid
and extending through the container such that the other end is disposed
outside the interior space, the liquid being delivered out of the interior
space through the liquid delivery path, due to the pressure within the
interior space which is raised by the pressurized gas; (d) second valve
means, disposed in the liquid delivery path, for selectively closing and
opening the liquid delivery path; and (e) a micro-porous membrane disposed
in a portion of the liquid delivery path which is upstream of the second
valve means, as viewed in a direction in which the liquid is delivered out
of the interior space. The micro-porous membrane filters the liquid to
remove microorganisms from the liquid delivered through the other end of
the liquid delivery path.
In the liquid purifying device of the present invention constructed as
described above, the liquid delivery path is held closed by the second
valve means provided therein, except when the liquid is purified and
delivered. In this closed condition, the liquid delivery path is protected
against contamination by microorganisms, the pressure within the interior
space of the container is kept higher than the atmospheric pressure, even
while the liquid delivery path is open with the second valve means placed
in its open position to permit the purified liquid to be delivered out of
the container. In this condition, the liquid in the delivery path or the
ambient air is prevented from flowing back through the delivery path in
the direction toward the interior space of the container. Thus, the
interior of the delivery path and the micro-porous membrane disposed in
the delivery path are completely protected against contamination by
microorganisms. Accordingly, the instant liquid purifying device is
capable of dispensing the liquid in a sterile condition, for a prolonged
period of time, with high liquid purifying stability.
The interior space of the container of the purifying device of the
invention is adapted to receive a pressurized gas such as a compressed or
liquefied gas, so that the pressure within the interior space is kept
higher than the atmospheric pressure. This arrangement permits the liquid
to be filtered by the micro-porous membrane under a higher pressure than
in the conventional device wherein the elastic container is contracted to
raise the pressure within the container. Accordingly, the instant device
assures a higher degree of efficiency of filtration of the liquid by the
micro-porous membrane, namely, a larger amount of flow of the liquid
through the micro-porous membrane per unit area of the membrane.
Therefore, the porous filter may be made compact, whereby the purifying
device may be made compact and small-sized.
According to the instant purifying device, the liquid may be replenished as
needed, or the container may be re-charged with the liquid when necessary.
Thus, the device may be used practically permanently, and is therefore
economical to use.
In one form of the present invention, the purifying device further
comprises pressurized-gas supply means for supplying one of a compressed
gas and a liquefied gas, as the pressurized gas, into the interior space
of the container through the first valve means. The pressurized-gas supply
means may be located outside the container, or alternatively disposed
within a structure of the container, such that the pressurized-gas supply
means communicates with the interior space through the first valve means.
An air filter may be provided in a passage between the pressurized-gas
supply means and the interior space of the container, for filtering the
pressurized gas to remove microorganisms from the pressurized gas which is
supplied into the interior space.
In another form of the invention, the second valve means includes a valve
stem, a valve seat and biasing means for normally holding the valve stem
in a closed position. The valve stem has a passage which constitutes a
part of the liquid delivery path. The passage is closed by the valve seat
when the valve stem is placed in the closed position. The valve stem is
axially movable against a biasing action of the biasing means, from the
closed position to an open position in which the passage is open to permit
the liquid to be delivered through the liquid delivery path. This type of
valve is generally used in a spray can which is charged with a pressurized
fluid. In this case, the liquid may be readily dispensed from the
container, by operating the valve stem to the open position, for example,
by finger pressure.
The pressurized gas used according to the invention may be a compressed gas
such as compressed ambient air, helium, argon, nitrogen, oxygen or carbon
dioxide, or a mixture thereof. Alternatively, the pressurized gas may be a
liquefied gas such as liquefied chloro-fluorinated hydrocarbon,
chlorinated hydrocarbon or hydrocarbon, or a mixture thereof. Among these
gases, ambient air is advantageous for its easy handling, low cost and
harmlessness.
In a still further form of the invention, the porous filter comprises an
array of micro-porous hollow fibers, each of which has a micro-porous wall
structure having a pore size determined so as to permit passage of the
liquid therethrough but inhibit passage of the microorganisms
therethrough. The micro-porous hollow fibers may preferably be formed of
polyolefin. The liquid delivery path may include a chamber in which the
array of micro-porous hollow fibers is accommodated. In this case, the
chamber has a header secured thereto so as to divide the chamber into two
parts, and the array of micro-porous hollow fibers is U-shaped such that
the U-shaped hollow fibers are held at opposite end portions thereof by
the header such that the remaining portions of the hollow fibers are
disposed in one of the two parts which is nearer to the end of the liquid
delivery path submerged in the liquid mass.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and optional objects, features and advantages of the present
invention will be better understood by reading the following detailed
description of presently preferred embodiments of the invention, when
considered in connection with the accompanying drawings, in which:
FIG. 1 is a schematic elevational view in longitudinal cross section of a
liquid purifying device constructed according to one embodiment of the
invention;
FIG. 2 is a partly cut-away elevational view in cross section of first
valve means in the form of a suction check valve used in the liquid
purifying device of FIG. 1;
FIGS. 3 and 4 are elevational views in cross section showing a construction
of second valve means in the form of a dispenser valve incoporated in a
container cap used in the device of FIG. 1, the figures indicating a
closed and an open position of the valve, respectively;
FIG. 5 is a fragmentary schematic elevational view in cross section of the
device, illustrating a micro-porous hollow fiber module used in the
device;
FIG. 6 is a partly cut-away perspective view of another embodiment of the
liquid purifying device of the invention;
FIG. 7 is a perspective view indicating a condition in which a liquid
container is received in a casing;
FIG. 8 is a schematic elevational view in longitudinal cross section of a
further embodiment of the liquid purifying device of the invention;
FIG. 9 is an enlarged fragmentary elevational view in cross section
illustrating an upper end portion of a cylinder which constitutes a part
of compressed-air supply means used in the embodiment of FIG. 8;
FIG. 10 is a plan view of the upper end portion of the cylinder of FIG. 9;
FIGS. 11, 12 and 13 are elevational views in longitudinal cross section of
known liquid purifying devices used as comparative examples compared with
the device according to the present invention, in evaluating the liquid
purifying capability;
FIGS. 14, 16 and 17 are schematic elevational views in longitudinal cross
section of further embodiments of the invention, which are constructed to
be connected to a separate compressed-gas supply means;
FIGS. 15 and 21 are schematic elevational views of first valve means in the
form of a suction check valve, FIG. 15 indicating a closed position of the
valve, FIG. 21 indicating an open position of the valve in communication
with a bomb which is filled with a compressed gas or liquefied gas;
FIGS. 18 and 19 are views depicting external compressed-gas supply means
connected to the liquid purifying devices of FIGS. 16 and 17,
respectively;
FIG. 20 is a schematic elevational view in longitudinal cross section of a
still further embodiment of the present invention; and
FIG. 22 is a schematic cross sectional view showing a modified form of
first valve means used in the liquid purifying device of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIG. 1, reference numeral 10 denotes a container in the
form of a bottle having an interior storage space 12, and an opening 14 at
its upper end communicating with the space 12. The container 10
accommodates a mass of a desired liquid 16, which is introduced through
the opening or upper open end 14. The container 10 is formed of a soft or
hard resin, a glass, a ceramic material, or any other suitable material
conventionally used for containers, which does not affect the liquid 16
stored in the container or which is not affected by the liquid 16.
The opening 14 of the container 10 is formed through a cylindrical
bottleneck 18 at its upper end, which is externally threaded, for
engagement with an internally threaded cap 20, so that the opening or
upper end 14 of the container 10 is gas- or fluid-tightly closed by the
cap 20, for providing the fluid-tight enclosed storage space 12.
The container 10 has a gas inlet 22 formed through a shoulder portion
thereof, so that the interior storage space 12 communicates with the
outside of the container. The container 10 is provided with first valve
means in the form of a suction check valve 24 fitted in the gas inlet 22.
As illustrated in FIG. 2, the check valve 24 is a generally cylindrical
member having a blind hole 26 which is open at one end thereof and closed
at the other end. The check valve 24 has a slit 30 formed through a
cylindrical wall 28 which defines the blind hole 26. In operation, the
cylindrical wall 28 is elastically deformed due to a difference between an
internal pressure in the blind hole 26 and an external pressure outside
the cylindrical wall 28, whereby a fluid may flow from the blind hole 26
into the interior space 12 of the container 10. However, the check valve
24 does not permit the gas in the container 10 to pass out of the
container 10 through the blind hole 26. In this sense, the check valve 24
is referred to as a "suction check valve" of a slit type, wherein only the
flow of the fluid into the container interior space 12 of the container 10
through the slit 30 is permitted. Namely, the suction check valve 24
permits a pressurized fluid (e.g., compressed or liquefied gas) to be
introduced into the interior space 12 through the gas inlet 22, while
inhibiting a discharge flow of the fluid from the space 12 through the gas
inlet 22 (i.e., through the slit 30).
To the suction check valve 24 fitted in the gas inlet 22 of the container
10, there is connected an open end of an air pump in the form of a
conventionally available rubber bulb 32, which is alternately contracted
and expanded so as to suck in the ambient air and feed the sucked air
through its open end connected to the check valve 24. Thus, the operation
of the rubber bulb 32 causes the compressed or pressurized air to flow
into the interior storage space 12 of the container 10, through the gas
inlet 22, i.e., through the check valve 24, whereby the pressure of the
air in the storage space 12 accommodating the liquid 16 is raised. It will
be understood that the rubber bulb or air pump 32 functions as means for
supplying a pressurized air into the interior storage space 12 of the
container, in the present embodiment.
In the meantime, the cap 20 is provided with second valve means in the form
of a dispenser valve 34 of a push-operated type. This dispenser valve 34
is a known one commonly used as a valve for spraying minute liquid
particles from a bomb. A typical arrangement of the dispenser valve 34 is
illustrated in FIG. 3, wherein the cap 20 has an integrally formed valve
housing 36 whose interior communicates with the interior space 12 of the
container 10. The dispenser valve 34 includes a valve body in the form of
a stem 42 which has an axial passage 38 formed in the longitudinal
direction and radial holes 40 communicating with the axial passage 38. The
axial passage 38 is open to the atmosphere. The valve housing 36 is
provided with an elastic valve seat 44 and a retainer 48 secured thereto.
The stem 42 of the dispenser valve 34 slidably engages the elastic valve
seat 44 and the retainer 48, so that the stem 42 is longitudinally movable
over a predetermined distance. The stem 42 is biased by biasing means in
the form of a coil spring 46 in the longitudinal direction from the spring
46 toward the retainer 48, so that the stem 42 is normally placed in its
closed position of FIG. 3. In this closed position, the radial holes 40
are closed by the valve seat 44, and the biasing force of the coil spring
46 is received by the retainer 48 via the stem 42 and the valve seat 44.
In FIG. 3, reference numeral 50 designates an operating head fixedly fitted
on the upper end portion of the stem 42. This head 50 is finger-operated
to place the dispenser valve 34 in its open position of FIG. 4. The
operating head 50 has an L-shaped passage 54 formed therethrough, for
fluid communication of the axial passage formed through the stem 42, with
a nozzle 52 which is secured to the head 50 such that the free open end of
the nozzle 52 is open to the atmosphere.
Thus, the dispenser valve 34 constructed as described above is normally
held in its closed position by the spring 46 and the retainer 48, with the
radial holes 40 closed by the valve seat 44, so that the interior storage
space 12 of the container 10 is closed to the atmosphere. When the
operating head 50 is finger-pressed, the stem 42 is moved to its open
position against the biasing action of the spring 46, whereby the elastic
valve seat 44 is elastically deformed by the stem 42, to expose the radial
holes 40 to the interior storage space 12, as illustrated in FIG. 4. In
this way, the storage space 12 of the container 10 is brought into
communication with the ambient atmosphere, through the interior of the
valve housing 36, radial holes 40 and axial passage 38 in the stem 42, and
L-shaped passage 54 and nozzle 52 of the operating head 50.
The lower open end of the valve housing 36 is connected to a feed tube 56
which extends through the interior storage space 12, to a level close to
the bottom of the container 10, such that the lower end of the feed tube
56 is open to the mass of the liquid 16 contained in the space 12. The
feed tube 56 is formed of a relatively soft material such as polyethylene,
and has a weight 58 fixedly mounted on its lower end portion so that the
feed tube 56 may be elastically flexed toward the lower cylindrical wall
portion of the container 10 when the container 10 is inclined, when the
amount of the liquid 16 left is relatively small, for example. This allows
the lower end of the feed tube 56 to be sufficiently submerged in the mass
of the liquid 16 even when its residual amount is small. As is apparent
from the above description, the present embodiment has a liquid delivery
path through which the interior space 12 of the container 10 communicates
with the outside of the container 10, for dispensing the liquid 16. The
liquid delivery path consists of the interior of the valve housing 36,
tube 56, radial holes 40, axial passage 38, L-shaped passage 54 and nozzle
52.
When the operating head 50 is finger-pressed to open the dispenser valve 34
after the pressure in the interior space 12 is raised by the repeated
operation of the air pump or rubber bulb 32, the liquid 16 accommodated in
the inerior space 12 is delivered through the nozzle 52, via the feed tube
56 and the dispenser valve 34, due to a difference between the pressure
within the space 12 and the atmospheric pressure. The delivery of the
liquid 16 from the nozzle 56 is stopped with the dispenser valve 34 closed
by releasing a finger pressure from the operating head 50.
The feed tube 56 includes a cylindrical chamber 60 formed at a
longitudinally intermediate portion thereof. The cylindrical chamber 60
has a relatively large diameter and accommodates a hollow or macaroni
fiber module 62. As illustrated also in FIG. 5, the hollow fiber module 62
includes a U-shaped array of a plurality of hollow fibers 64 each having a
micro-porous wall structure, and a header 66 to which the end portions of
the U-shaped array consisting of the opposite open ends of the fibers 64
are bonded with a suitable adhesive such as polyurethane. The module 62 is
disposed in the cylindrical chamber 60 of the feed tube 56, with the
header 66 fixedly or removably supported by the wall of the chamber 60,
such that the chamber 60 is divided by the header 66 into two parts.
While the opposite open ends of the micro-porous hollow fibers 64 of the
module 62 are open to the part of the chamber 60 nearer to the valve
housing 36, the open ends of the fibers 64 are fluid-tightly sealed with
respect to the other part of the chamber 60 in which the substative
portion of the U-shaped array of the fibers 64 is accommodated. Namely,
the header 66 is fluid-tightly sealed with respect to the inner surface of
the chamber 60, so that the liquid 16 fed into the upstream part of the
chamber 60 may flow into the valve housing 36 through the wall of the
hollow fibers 64 of the module 62.
The micro-porous wall structure of each of the multiple hollow fibers 64 of
the module 62 has pores whose diameters are large enough to permit the
liquid 16 to pass therethrough, but are small enough to inhibit the
passage of bacteria in the liquid 16, thereby filtering the bacteria.
Preferably, in order to remove microorganisms in the liquid 16, the
diameters of the pores of the hollow fibers 64 are determined so that the
micro-porous structure may remove or trap pseudomonas diminuta ATCC 19146.
Namely, a typical micro-porous structure of the fibers 64 should prevent
the passage of particles having a diameter of 0.2-0.3 .mu.m.
When it is desired to filter virus as well as microorganisms, the
micro-porous structure of the hollow fibers 64 should have smaller pores.
For example, the diameters of the pores should be determined so as to
prevent the passage of particles of 0.08 .mu.m or larger, 0.07 .mu.m or
larger, and 0.025 .mu.m or larger, for the micro-porous structure to be
able to remove influenza virus, Bovinerota virus, and polio virus and/or
hepatitis B virus, respectively.
The micro-porous hollow fibers 64 may be made of high polymers, preferably,
such as polyolefin, polyvinyl alcohol, polysulfone, polyacrylonitrile,
cellulose acetate, polymethyl methacrylate and polyamide, by a suitable
known method such as micro phase separating method or drawing method.
Particularly, the micro-porous follow fibers of polyolefin by a drawing
technique are preferably used according to the present invention.
In the above case, polyolefin is melt-spun at a temperature slightly lower
than the ordinary spinning temperature, and at a comparatively high draft,
to obtain un-drawn oriented crystal hollow fibers which have a "stacked
lamellae" structure. The thus obtained un-drawn hollow fibers are
heat-treated as needed, and then drawn at a suitable temperature, in a
single layer or two or more layers. In this drawing process, the
non-crystallized or incompletely crystallized portions between the
lamellae are drawn, while preventing the unfolding of the lamellae, at a
temperature lower than the crystalline dispersive temperature at which the
molecular movement within the crystals becomes active. As a result of the
drawing process, there is obtained a slit-like porous structure which has
an outer shell consisting of the crystalline lamellae, and inner minute
threadlike fibril elements. The prepared porous structure is thermally
set, whereby the hollow fibers having micro pores are produced. The pore
size of the porous structure may be controlled by the spinning, drawing
and thermally setting conditions.
The thus fabricated polyolefin micro-porous hollow fibers can let much
water run through the porous structure in spite of their high rejection to
the particles, and have at the same time a relatively high strength.
Accordingly, the hollow fibers are easily processed into a module (62) and
are highly resistant to mechanical stresses during use. Such micro-porous
hollow fibers are available from Mitsubishi Rayon Co., Ltd., Japan, as
KPF190M (made of polypropylene), EHF390A (made of polyethylene), and
EHF270H (made of polyethylene). The first two types are suitable for
filtering polio virus and/or hepatitis B virus, and all of the three types
are suitable for filtering bovinerota virus. For filtering microorganisms,
EHF270T and EHF270W also available from Mitsubishi Rayon may be suitably
used, as well as the three types indicated above. When it is desired to
filter only the microorganisms, the type EHF270T is most preferable, for
its high permeability to water and high capability of trapping the
microorganisms. The type EHF270H exhibits a high degree of permeability,
and is capable of filtering some species of virus.
When the liquid 16 is an aqueous solution, the porous hollow fibers 64
preferably have a porous structure which exhibits sufficiently high
hydrophilic property. When the polyolefin porous hollow fibers having
hydrophobic property are used for filtering the aqueous solution, the
hollow fibers should preferably be processed to give the porous structure
hydrophilic property. When the liquid 16 is an olive oil or other oily
liquid, it is desirable that the porous hollow fibers 64 exhibit
hydrophobic property.
In the simple liquid purifying device constructed as described above,
pressing the operating head 50 will cause the liquid 16 to be fed into the
chamber 60 of the feed tube 56, from the storage space 12 of the container
10 whose pressure is elevated by the air introduced by the rubber bulb 32.
As a result, the liquid 16 in the chamber 60 permeates through the porous
structure of the hollow fibers 64 of the module 62, whereby the
microorganisms are filtered by the porous hollow fibers 64. Accordingly,
the liquid 16 delivered through the nozzle 52 is sterile or free of
microorganisms.
Further, the liquid delivery path or passage (including the tube 56) and
the hollow fiber module 62 disposed therein are completely protected
against contamination by microorganisms, by the normally closed dispenser
valve 34, which is disposed near the open end of the liquid delivery path.
That is, the liquid delivery path is normally closed by the dispenser
valve 34, between the external open end and the hollow fiber module 62.
Accordingly, the liquid delivery path, hollow fiber module 62 and the
liquid 16 are effectively protected against contamination by
microorganisms while the instant device is not in use.
Furthermore, the instant liquid purifying device is protected against
contamination by microorganisms even while the dispenser valve 34 is in
the open position. More specifically, the liquid 16 is forced to flow
through the open dispenser valve 34, always in the direction toward the
external open end of the liquid delivery path (toward the nozzle 52), due
to the higher pressure in the interior storage space 12 than the external
atmospheric pressure Even in the open position of the dispenser valve 34,
there may arise no flow of the liquid 16 in the reverse direction toward
the interior space 12 of the container 10, whereby the entry of external
microorganisms into the liquid delivery path, and the entry through the
open dispenser valve 34 into the feed tube 56 may be effectively avoided
or minimized.
Thus, the instant liquid purifying device is capable of filtering
microorganisms by means of the porous hollow fibers 64, while effectively
protecting the liquid 16 in the delivery path against contamination by
microorganisms. Namely, the device maintains a highly stable purifying
function for a relatively long period of time.
In the liquid purifying device of the type described above, the permeation
of the liquid 16 through the micro-porous structure of the hollow fibers
64 occurs due to the comparatively high pressure within the container.
Consequently, the efficiency of filtering of the liquid 16 (that is, the
rate of flow of the liquid per unit area of the fibers 64) by the hollow
fibers 64 may be held at a relatively high level. Accordingly, the hollow
fiber module 62, and the liquid purifying device as a whole, may be made
relatively compact and small-sized. This is an additional advantage of the
present device.
Moreover, since the rubber bulb 32 as the compressed-gas supply means for
pressurizing the interior space 12 is provided outside the container 10,
the container may be readily re-charged with the liquid 16, by simply
removing the cap 20.
In the instant embodiment, the ambient atmosphere (air) is used as a gas
for pressurizing the interior storage space 12 of the cotnainer 10. Thus,
the instant liquid purifying device does not cause an environmental
pullution (air pollution) as encountered where a special compressed gas
such as a compressed flon gas is used.
In the instant embodiment, the push-operated type dispenser valve 34 as
used for a spray can or bomb charged with a pressurized fluid is used as
the second valve means for dispensing the purified liquid 16 by
finger-pressing the operating head 50. Therefore, the purification and
dispensation of the liquid 16 may be easily and efficiently effected by a
single hand.
In the instant purifying device, the hollow fiber module 62 disposed in the
liquid delivery path for filtering microorganisms contained in the liquid
16 has a relatively large filtering surface area, since the module 62
consists of an array of the multiple hollow fibers 64. Accordingly, the
instant device permits a sufficiently large amount of the liquid 16
purified per unit time, i.e., a sufficiently high rate of delivery of the
purified liquid 16, even when the liquid 16 is a comparatively viscous
liquid such as an olive oil. This favorably results in reducing the size
of the device, and provides improvements in ease of handling or
manipulation of the device.
Referring next to FIG. 6, another embodiment of the liquid purifying device
will be described. This embodiment uses a modified form of the
compressed-gas supply means for pressuring the interior storage space 12
of the container. In the interest of brevity and simplification, the same
reference numerals as used with respect to the preceding embodiment will
be used in FIG. 6, to identify the functionally corresponding elements,
and redundant description of these elements will not be provided.
In the instant modified embodiment, the lower portion of the container 10
is inserted or put within a cylindrical casing 70 which is closed at its
bottom end. Between the bottom walls of the casing 70 and the container
10, there is disposed a bellows type air pump 72 which is formed of an
elastic material such as a soft resin material. The air pump 72 is secured
at its opposite ends to the opposite bottom walls of the casing 70 and
container 10. The interior of the bellows of the air pump 70 communicataes
with the external space (ambient atmosphere) through a check valve (not
shown), and with the interior space 12 of the container 10 through a feed
tube 78 extending into the space 10, and a suction check valve (first
valve means) 76.
The air pump 72 sucks in the ambient air through the appropriate check
valve and compresses the sucked air, when the bellows is alternately
contracted and expanded by reciprocatingly moving the container 10
relative to the casing 70. Thus, the compressed air is forced into the
interior space 12 through the feed tube 78 and the suction check valve 76.
Referring further to FIG. 7, reference numerals 80 designate tabs which are
formed on the outer circumferential surface of the container 10. The tabs
80 are normally held in engagement with corresponding cutouts 82 formed
through the cylindrical wall of the casing 70, so that the container 10 is
held in its rest position under the elastic | | |
