U.S. patent application number 09/828946 was filed with the patent office on 2001-08-16 for water quality meter and water quality monitoring system.
Invention is credited to Enoki, Hideo, Fukunaga, Masao, Ishihara, Tamio, Kanamaru, Masatoshi, Miyake, Ryo, Mori, Sadao, Saito, Koji, Terayama, Takao, Yamada, Katsutoshi.
Application Number | 20010013488 09/828946 |
Document ID | / |
Family ID | 26424270 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010013488 |
Kind Code |
A1 |
Fukunaga, Masao ; et
al. |
August 16, 2001 |
Water quality meter and water quality monitoring system
Abstract
A water quality meter is composed of a plurality of analyzing
units for analyzing water samples introduced from a water
distribution pipe, each analyzing unit including a reagent mixing
cell and a measuring cell, and a liquid introducing unit integrated
with the analyzing units, which is composed of a single member in
which a plurality of fluid flow paths for feeding various types of
liquid including the water sample into the analyzing unit are
formed. Furthermore, the cells and the plurality of
three-dimensional fluid flow paths formed in the single member are
fabricated by a micro-fabrication technique using photo-curing
resin.
Inventors: |
Fukunaga, Masao;
(Hitachinaka-shi, JP) ; Ishihara, Tamio;
(Hitachinaka-shi, JP) ; Saito, Koji; (Mito-shi,
JP) ; Yamada, Katsutoshi; (Hitachinaka-shi, JP)
; Enoki, Hideo; (Niihari-gun, JP) ; Mori,
Sadao; (Tsuchiura-shi, JP) ; Miyake, Ryo;
(Tsukuba-shi, JP) ; Terayama, Takao; (Ushiku-shi,
JP) ; Kanamaru, Masatoshi; (Inashiki-gun,
JP) |
Correspondence
Address: |
KENYON & KENYON
1500 K STREET, N.W., SUITE 700
WASHINGTON
DC
20005
US
|
Family ID: |
26424270 |
Appl. No.: |
09/828946 |
Filed: |
April 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09828946 |
Apr 10, 2001 |
|
|
|
09281098 |
Mar 29, 1999 |
|
|
|
Current U.S.
Class: |
210/85 ; 210/93;
210/96.1 |
Current CPC
Class: |
C02F 2201/009 20130101;
C02F 2201/008 20130101; C02F 2209/40 20130101; C02F 2103/02
20130101; C02F 2209/29 20130101; G01N 33/1893 20130101; C02F 1/008
20130101; Y02A 20/212 20180101; C02F 2209/11 20130101 |
Class at
Publication: |
210/85 ; 210/93;
210/96.1 |
International
Class: |
B01D 017/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 1998 |
JP |
10-83208 |
Jul 15, 1998 |
JP |
10-200071 |
Claims
What is claimed is:
1. A water quality meter sized and configured for attachment to a
location on a pipe so as to draw water out of said pipe prior to
its supply to an end use in a water distribution system which
supplies water that is obtained by purifying raw water as drinking
water to each end user via a water distribution piping network,
said water quality meter comprising: a plurality of analyzing
units, each of which includes a measurement flow path in which
liquid flows, for introducing a water sample into said measurement
flow path from said location on said pipe, and analyzing said water
sample; a photometer which is situated at a measurement flow path
in at least one of said analyzing units, for irradiating liquid
flowing in said measurement flow path with light and measuring
absorbency of said liquid; and a liquid introducing unit comprising
a single member in which a plurality of fluid flow paths for
feeding a plurality of types of liquid including said water sample
into said plurality of analyzing units is formed.
2. A water quality meter sized and configured for attachment to a
location on a pipe so as to draw water out of said pipe prior to
its supply to an end use in a water distribution system which
supplies water that is obtained by purifying raw water as drinking
water to each end user via a water distribution piping network,
said water quality meter comprising: a plurality of analyzing
units, each of which includes a measurement flow path in which
liquid flows, for introducing a water sample into said measurement
flow path from said location on said pipe, and analyzing said water
sample; a pair of electrodes, which is situated in a measurement
flow path in at least one of said analyzing units for measuring one
of electric conductivity and pH; and a liquid introducing unit
comprising a single synthetic member in which a plurality of fluid
flow paths for feeding or expelling a plurality of types of liquid
including said water sample into said plurality of analyzing units
is formed.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a water quality meter to
measure the quality of drinking water distributed via pipes and a
water quality monitoring system using the water quality meter.
[0002] As an example of a water quality monitoring system, an
automatic water quality measurement system known to be used in
Tokyo, and its design specification is described in a paper of The
Journal of The Society of Instrument and Control Engineers (Japan),
Vol. 33, No. 8, August 1994, pp. 649653.
[0003] In this water quality measurement system, a water quality
meter is provided at each of the piping subsystems composing a
water supply piping network at a water supplier, and it
continuously measures the water quality of each piping system.
Furthermore, the measured water quality is transmitted to a control
center with a telemeter at regular intervals.
[0004] As a means for measuring the water quality for end users, a
manual analysis in which the distributed water of the end user is
sampled and manually analyzed with a reagent or an off-line
measurement using a portable water quality meter is performed.
[0005] In a conventional water quality monitoring system such as
the above-mentioned system, since a water quality meter is provided
in each water piping subsystem, the number of the provided meters
is comparatively small, and the average quality of water
distributed in each subsystem can be determined. However, the
conventional system has a problem in that the quality of water
which end users drink is not determined.
[0006] The quality of water is measured and controlled at a water
supplying facility. However, the water quality is degraded while
water passes through a water distribution piping network. For
example, the concentration of chlorine to maintain the bactericidal
activity in drinking water is decreased due to chemical reactions
with the materials composing the water distribution system or with
components contained in the drinking water. Also, the chromaticity
of drinking water is increased by coloring due to stains on the
inside surfaces of the pipes, and the turbidity of drinking water
is also increased due to the peeling of deposits on the inside
surfaces of the pipes. Although the above-mentioned degradation of
water quality is naturally caused in main pipes, this degradation
is more strongly caused in end side pipes in a water distribution
piping network or in pipes in the houses of end users. It is well
known that the concentration decrease of residual chlorine in water
is proportional to the staying time in water. The staying time of
chlorine in water is longer in the end side pipes than in the main
pipes in which water always flows. Therefore, the concentration of
residual chlorine is decreased in the end side pipes. Furthermore,
in the extreme case, the concentration of chlorine becomes zero,
and water without the bactericidal activity may be drunk. The
concentration decrease of residual chlorine causes the degradation
of the bactericidal activity of water, which may cause the breeding
of microbes, and especially of pathogenic microbes (for example,
0-157 coliform bacilli), and further cause a social problem
concerning the safety and health of people. On the other hand,
increasing the concentration of chlorine in drinking water to a
higher level to maintain the bactericidal activity of drinking
water causes the problem of a bleaching powder smell or a safety
problem of producing harmful substances such as a chloric residuum
of trihalomethane.
[0007] As to the chromaticity and the turbidity of drinking water
in the end side pipes also, problems similar to the above-mentioned
problems are caused due to the long staying time of water. In
particular, a water storage tank is used in aggregate residences or
business establishments, and if the water storage tank is not well
managed, the above problems are often caused.
[0008] In an ideal water quality management system, the quality of
water in the end side pipes, which end users drink, is monitored,
and is adequately managed based on the results of the monitoring.
The size of a conventional water quality meter, for example, 1.2
m.times.1.8 m.times.0.6 m, is so large that it cannot be provided
in places such as a typical house or aggregate residences. Since
the price of a conventional water quality meter or the cost of
providing a conventional water quality meter is high, the number of
conventional water quality meter provided in typical houses or
aggregate residences is small. Furthermore, since professional
expertise is required for the maintenance of a conventional water
quality meter and the consideration for the safety of a meter is
important, it is difficult to use a conventional water quality
meter in typical houses. Thus, conventional water quality meters
have not been provided at a desirable pipe location in the
neighborhoods of houses of end users or of aggregate
residences.
[0009] On the other hand, although the quality of water at the end
side of a water distribution piping network can be measured by a
manual analysis or with a portable water quality meter, it takes a
long time for measuring results to be obtained, and water quality
data cannot be continuously obtained, which makes it impossible to
determine the range of variation in water quality in a day, or the
transient behavior of water quality.
[0010] In water quality data, the maximum and minimum values in a
transient state are important, and the development of a system and
a control method of the system to reduce the variation in these
values is mandatory. Therefore, a manual analysis or a portable
water quality meter is not suitable for the above continuous
monitoring system.
[0011] In a very rare example, by restricting measurement
categories and places in which water quality detectors are
provided, for example, by providing residual chlorine concentration
detectors at the rate of one per ten to thirty-plus thousand end
users at end side pipes of a water distribution system, an on-line
water quality measurement has been performed. However, conventional
water quality meters used in the above water quality measurement
can measure only one category, and are also large and expensive
meters similar to ones used in water purifying facilities.
Therefore, places in which such meters are set cannot be easily
obtained, and it is also to difficult to obtain sufficiently
detailed measurements of water quality.
SUMMARY OF THE INVENTION
[0012] The present invention has been achieved in consideration of
the above described problems, and is aimed at providing a water
quality meter and a water quality monitoring system in which water
quality meters can be set at places near the end side pipes of a
drinking water distribution system, and further can measures a
plurality of measurement categories.
[0013] To attain the above object, the present invention provides a
water quality meter attached at a location on a pipe in a water
distribution system which supplies water that is obtained by
purifying raw water as drinking water to each end user via a water
distribution piping network, the water quality meter comprises:
[0014] at least one analyzing unit for analyzing a water sample
introduced from the location on the pipe; and
[0015] a liquid introducing unit composed of a single member in
which a plurality of fluid flow paths for feeding various types of
liquid including the water sample into the analyzing unit are
formed.
[0016] Moreover, in the above water quality meter, the member
composing the liquid introducing unit is made of plastic which is
cured by ultraviolet irradiation.
[0017] Further, in the above water quality meter, the analyzing
unit includes a measurement flow path in which liquid flows, and a
plurality of apertures open to the measurement flow path, with
liquid to be fed into the analyzing unit from the liquid
introducing unit being introduced to the measurement flow path
through the apertures.
[0018] Furthermore, the above water quality meter further includes
a plurality of containers for liquid to be fed into the analyzing
unit, the liquid in the containers being fed into the analyzing
unit via the fluid flow paths in the liquid introducing unit.
[0019] Still further, in the above water quality meter, liquid
stored in each of the containers is one of a reagent prepared
corresponding to a measurement category, washing water to wash the
measurement flow path, and reference water to be used for
correcting a result of a measurement performed by the analyzing
unit.
[0020] Also, in the above water quality meter, the containers are
detachably attached to the water quality meter.
[0021] Additionally, in the above water quality meter, the
analyzing unit is fabricated by using a micro-fabrication
technique.
[0022] On top of that, in the above water quality meter, a
plurality of analyzing units is connected to the liquid introducing
unit.
[0023] Moreover, in the above water quality meter, a plurality of
analyzing units analyzes the same measurement category.
[0024] Also, the present invention provides a water quality
monitoring system for monitoring the quality of water distributed
by a water distribution system including water purifying facilities
to purify raw water taken in from rivers, lakes, and/or wells to a
quality suitable for drinking water, water distribution facilities
for distributing the water purified by the water purifying
facilities, a water quality control center for monitoring and
controlling the water purifying facilities and the water
distribution facilities, and a water distribution piping network
for feeding the purified water to end users, the water quality
monitoring system comprises:
[0025] water quality monitoring meters set at predetermined
locations in the water distribution piping network, each of the
water quality monitoring meters including at least one analyzing
unit for analyzing a water sample introduced from the location on
the pipe; a liquid introducing unit composed of a single member in
which a plurality of fluid flow paths for feeding various types of
liquid including the water sample into the analyzing unit are
formed; and a transmission unit for transmitting to the control
center;
[0026] wherein results of measurements performed by each of the
water quality meters are transmitted to the water quality control
center via the transmission unit of the water quality meter.
[0027] Further, in the above water quality monitoring system, each
of the water quality meters is set in one of a manhole, a fire
hydrant, a water meter box, a utility in the house of an end user,
all of which are provided in the water distribution network.
[0028] Still further, in the above water quality monitoring system,
the transmission between the control center and each of the water
quality meters is performed with a radio transmission.
[0029] Furthermore, in the above water quality monitoring system,
each of the water quality meter includes a solar battery and a
storage battery connected to the solar battery via a diode, and the
water quality meter is powered by energy fed from the solar battery
and/or the storage battery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a block diagram showing the composition of a water
quality meter of an embodiment according to the present
invention.
[0031] FIG. 2 shows an example of the composition of a drinking
water distribution system using a water quality monitoring system
with water quality meters of the embodiment according to the
present invention.
[0032] FIG. 3 shows an example of a method of setting a water
quality meter at an end user side in a water quality monitoring
system of an embodiment according to the present invention.
[0033] FIG. 4 is a schematic block diagram showing the internal
composition of a water quality meter of the embodiment according to
the present invention.
[0034] FIG. 5 shows the detailed structure of a mother board used
in the embodiment according to the present invention.
[0035] FIG. 6 is a perspective view showing a three-dimensional
structure of fluid flow paths used in the mother board.
[0036] FIG. 7 is a vertical cross section showing the composition
of a mixing and analyzing unit in a water quality meter of the
embodiment according to the present invention.
[0037] FIG. 8 shows the composition of an analyzing cell in each
mixing and analyzing unit.
[0038] FIG. 9 shows another example of a method of setting a water
quality meter at an end user side in the water quality monitoring
system of the embodiment according to the present invention.
[0039] FIG. 10 shows an example of a water quality monitoring
system of another embodiment according to the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0040] Hereafter, details of the embodiments will be explained with
reference to the drawings. FIG. 2 shows an example of a basic
composition of a drinking water distribution system using a water
quality monitoring system with water quality meters of the
embodiment according to the present invention. Raw water taken from
rivers, lakes, wells, and so on is purified to make the water
quality suitable for drinking water by the water purifying
facilities 1, and is sent to the water distribution facilities 2.
The drinking water output from the water distribution facilities 2
is introduced into a water quality meter 8 via a water distribution
system main pipe 4 and a water distribution subsystem main pipe 5,
or further via a water supplier sub-pipe 6 and an end-user side
pipe 7. Each water quality meter includes a transmission means, and
can perform the transmission with a water quality control center 3.
Information on the quality of the distributed drinking water which
has been measured in an on-line manner by the water quality meters
8 is transmitted to the water quality control center 3 by a radio
means, a line transmission method, a transmission satellite, etc.
The water quality control center 3 then processes the received
information, and controls the water purifying facilities 1 and the
water distribution facilities 2 so as to ensure that the quality of
distributed water is in a state suitable for drinking water.
[0041] FIG. 3 shows an example of a method of setting a water
quality meter at an end user side in a water quality monitoring
system of an embodiment according to the present invention. The
distributed drinking water branched from the water distribution
subsystem main pipe 5 on the water supplier side, the water
supplier side sub-pipe 6, or the end-user side pipe 7, enters the
end-user piping 11 via a shut off valve 10 and a water meter 9, and
a plurality of measurement categories for the quality of the
drinking water is simultaneously measured by the water quality
meter 8. The end-user piping is a network system composed of pipes,
and some of the drinking water is fed to an end user from a
location on the end user piping 11 via a feed water faucet 12 such
as a water tap faucet. The water quality meter 8 can be attached
before or after the water meter 9, or in a water meter container
box, and further has a size such that it can be easily set in a
manhole, a fire hydrant, a utility in the house of an end user, or
in the vicinity of a water tap faucet. Although the composition of
the water quality meter 8 is later explained in detail, in
accordance with the embodiment of the present invention, the water
quality meter 8 can be easily set in a space of 10 cm.times.20
cm.times.20 cm.
[0042] FIG. 4 is a schematic block diagram showing the internal
composition of a water quality meter of the embodiment. Water
sample introduced from the pipes 4, 5, 6, and 7 via a liquid
introducing unit 13 is measured for each measurement category by
the mixing and analyzing unit 110, using a predetermined measuring
sequence, and the measured value for the category is converted to
an electrical signal. Further, the electrical signal is sent to a
signal processing/control unit 18. The mixing and analyzing unit
110 is composed of a plurality of reagent mixing parts 14a-14c
provided for the respective measurement categories, and a plurality
of measuring parts 15-17 corresponding to the respective reagent
mixing parts 14a-14c. Each of the plurality of reagent mixing parts
14a-14c and the plurality of measuring parts 15-17 is formed as a
cell with a module structure. Therefore, it is easy to provide
cells corresponding to the number of required measurement
categories. The measurement categories are the concentration of
residual chlorine, the turbidity, the chromaticity, the
conductivity, pH, the concentration of chloric residua such as
trihalomethane, the number density of pathogenic microbes, and so
forth. The signal processing/control unit 18 receives power from a
power source unit 20, and processes result data of measurements
performed by the mixing and analyzing unit 110. The result data
processed by the signal processing/control unit 18 are converted to
signals for transmission by a transmission unit 19. Further, the
converted signals for transmission are transmitted to the water
quality control center 3 by a radio means, or a telemeter via an
exclusive transmission line or a public transmission line.
[0043] By applying a micro-fabrication technique, the mixing and
analyzing unit 110 can be fabricated in a very small size, and the
power consumption and the amount of the water sample and mixed
reagent can be reduced. Accordingly, a battery can be used as the
power source unit 20, and withdrawal collection or evaporation of
the exhaust water becomes possible, which makes constructing work
for equipment to process the exhaust water from the water quality
meter 8 unnecessary. In addition, wiring works for data
transmission from the water quality meter 8 also become unnecessary
because a radio data transmission line is used. Thus, the freedom
of choice in locating the water quality meter 8 is greatly
expanded.
[0044] In the following, the detailed composition of a water
quality meter of the embodiment will be explained with reference to
FIG. 1. The water quality meter 8 is constructed by attaching pumps
(74, 84, 87, and 90), electromagnetic valves (69, 73, 83, 93,
75a-75c, 85a-85c, and 91a-91c), and analyzing cells (76, 77, and
78), to a mother board 101. Here, diaphragm valves and metering
pumps (syringe pumps) are used for the pumps 87 and 89 and the
pumps 74 and 84, respectively. Moreover, fluid flow paths are
formed in the regions surrounded by dotted lines shown in FIG. 1,
inside the mother board 101. Drinking water 52 flowing in a pipe 51
at the water supplier or end user side is sampled via a pipe 53.
Further, the sampled drinking water passes through a manual valve
54, a pipe 55, a depressurization valve 56, a pipe 57, a manual
valve 58, and is sent to an exhaustion conduit 60 from a pipe
59.
[0045] A part of the water sample 52 whose pressure is maintained
at a constant value is branched from the pipe 57 by the pipe 61,
and is introduced to a filter 63 for removing comparatively large
extraneous substances in the branched water via a manual valve 62.
Further, the water is introduced to a degassing tank 66 via a flow
path 65 in the mother board 101. Inside the degassing tank 66,
bubbles contained in the water sample 52 gather in the upper part
of the degassing tank 66, and this gas is exhausted at appropriate
intervals to the exhaust water conduit 60 from the mother board 101
via an electrode 69 and a flow path 70.
[0046] Water sample 71 in the tank 66, from which bubbles are
removed, is introduced to the metering pump 74 via a flow path 73
and the electromagnetic valve 73. Moreover, the water sample 71 is
selectively sent to the plurality of analyzing cells 76, 77, and
78, each analyzing cell analyzing an independent measurement
category, via the plurality of electromagnetic valves 75a, 75b, and
75c, and a plurality of fluid inlet holes 71a, 71b, and 71c. The
shape and size of the analyzing cells 76-78 are the same, and the
arrangement of the flow paths in the cells is also the same, so
that the cells interchangeable with each other. Also, these
analyzing cells are detachably held on the upper face of the mother
board 101. Furthermore, a plurality of cartridges 79, 80, and 81
containing liquid are held detachably held on the outside of the
mother board 101, and liquid contained in each cartridge is fed to
the mother board 101. Liquid 82 (reagent) from the cartridge 79 is
selectively sent to the analyzing cells 76-78, the electromagnetic
valve 83 and the metering pump 84, via one of the plurality of
electromagnetic valves 85a-85c that corresponds to the selected
analyzing cell, and also via one of the plurality of flow inlet
holes 82a-82c that corresponds to the selected analyzing cell.
[0047] Similarly, liquid 86 (washing water) from the cartridge 80
is selectively sent to the analyzing cells 76-78 by the metering
pump 87, via one of the plurality of electromagnetic valves 88a-88c
that corresponds to the selected analyzing cell, and also via one
of the plurality of flow inlet holes 86a-86c that corresponds to
the selected analyzing cell. Also, liquid 89 (reference water) from
the cartridge 81 is selectively sent to the analyzing cells 76-78
by the metering pump 90, via one of the plurality of
electromagnetic valves 91a-91c that corresponds to the selected
analyzing cell, and also via one of the plurality of flow inlet
holes 89a-89c that corresponds to the selected analyzing cell.
[0048] Each analyzing cell (whose structure is later explained in
detail) is composed of a reagent mixing part in which mixing or a
reaction of the water sample with the liquid fed from each
cartridge is performed; or liquid fed from each cartridge flows
through along with a measuring part for measuring liquid sent from
the reagent mixing part for a predetermined measurement category,
and is shaped by a micro-fabrication technique. Thus, although the
size of this analyzing cell is very small, its function is
equivalent to that which one set of analyzing equipment of a
conventional size possesses. Last, exhaust water 92 whose analysis
has been finished is expelled to the outside of the water quality
meter 8 via flow paths 70. If the exhaust water 92 is harmful, or
there is not a water exhaust utility, the exhaust water 92 is
expelled into an exhaust water storage container 95.
[0049] Furthermore, in the following, details of the mixing and
analyzing unit 110 will be explained with reference to FIG. 5. The
shape of the mother board 110 is a rectangular parallelepiped, and
there are connection holes for inputting and outputting water
sample on the right side face of the mother board 110 with the
electromagnetic valves 93 and 69 being attached to the
corresponding holes. Moreover, the flow inlet holes 89a-89c and
82a-82c for inputting the reference water 89 and the reagent 82 are
arranged longitudinally, and the electromagnetic valves 88a-88c and
91a-91c are attached to the corresponding holes. On both sides of
each of the longitudinally arranged inlet holes, there is a pair of
internal threads, and each of the electromagnetic valves 93, 69,
88a-88c, and 91a-91c, is fixed to the mother board 101 with screws
by using the internal threads.
[0050] Similarly, there are flow inlet holes for inputting water
sample on the left side face of the mother board 101, and the
electromagnetic valves 83 and 73 are attached to the corresponding
holes. Moreover, the flow inlet holes 71a-71c for inputting water
sample and 86a-86c for inputting the washing water 86 are arranged
longitudinally, and the electromagnetic valves 75a-75c and 85a-85c
are attached to the corresponding holes. Also, on both sides of
each of the longitudinally arranged inlet holes, there is a pair of
internal threads, and each of the electromagnetic valves 83, 73,
85a-85c, and 75a-75c, is fixed to the mother board 101 with screws
by using the internal threads.
[0051] On the other hand, on the upper face of the mother board
101, there are open holes are formed to communicate with the pumps
74, 84, and 87, so that pressure is applied to fluid flowing in the
mother board 101 so as to send the fluid onward. Furthermore, the
analyzing cells 76-78 are fixed to the upper face. These analyzing
cells 76-78 are connected to the mother board 101 via the flow
inlet holes 82a-82c, 71a-71c, 89a-89c, 86a-86c, and 309a-309c.
[0052] The main fluid flow paths formed in the mother board 101 are
explained below with reference to FIG. 6. All the internal fluid
flow paths (paths 65, 68, 70, 72, 92, 94, etc.) are
three-dimensionally formed in the mother board 101.
[0053] On the back face of the mother board 101, there are flow
inlet holes for introducing the water sample 52, the reagent 82,
the washing water 86, and the reference water 89. As mentioned
above, the shape of the mother board 101 is a rectangular
parallelepiped, and on its outer surface, there are a plurality of
flow inlet or connection holes and a plurality of internal threads
for holding valves, pumps, analyzing cells, etc. via sealing
elements without connection pipes on the surface of the mother
board 101.
[0054] If the resin parts are removed from an illustration of the
mother board 101, and only the internal fluid flow paths are
illustrated, the paths are seen as shown in FIG. 6. Such
three-dimensional fluid flow paths have rarely been realized. If
one intends to form such stereoscopic fluid flow paths, the paths
should be conventionally formed by superimposing a plurality of
plates in which two-dimensional paths are mechanically formed. This
embodiment adopts a photo-forming method in which a
three-dimensional shape is formed by irradiating a part of the
shape in liquid ultraviolet-curing type plastic in a transparent
container with an ultraviolet laser beam. To form the
three-dimensional fluid flow paths in this embodiment, parts of the
three-dimensional fluid flow paths in ultraviolet-curing-type
plastic are not irradiated with an ultraviolet laser beam, and
these parts remain as liquid plastic. Afterward, by washing out the
liquid plastic which has not cured, the remaining solidified
plastic parts complementary to the three-dimensional fluid flow
paths can be obtained. In this embodiment, transparent
ultraviolet-curing-type epoxy resin is used so that states inside
the fluid flow paths can be observed. The photo-forming method can
cheaply and quickly form a three-dimensional shape using only
three-dimensional data of the shape (which are used for CAD),
without a shaping mold which and further improves the reliability
of the connection parts of the fluid flow paths and the external
equipment such as valves, pumps, and so on.
[0055] As shown in FIG. 6, the sizes or shapes of the fluid flow
paths in the mother board 101 can be freely designed while
satisfying a constraint in that two points are connected with the
shortest three-dimensionally smooth-curve route without steep
bending, which causes very little stagnation of dust and bubbles in
fluid in the fluid flow paths.
[0056] Furthermore, since a branch or a connection in the flow
paths can be formed at an optional position inside of the mother
board 101 without a coupling element, mixing or separating of fluid
can be performed at an optional position inside of the mother board
101. The degassing tank 66 can also be formed in a space with the
three-dimensional shape of a degassing tank 104 shown in FIG.
6.
[0057] In the above monitoring system according to the present
invention, the plurality of pumps and electromagnetic valves are
controlled by a sequence control method, and drinking water 52
sampled from the drinking water distribution pipe 51 and liquid in
each of the plurality of cartridges are introduced into the
corresponding reagent mixing part. Further, In the reagent mixing
part, the introduced liquid reacts with the water sample, and the
result of the reaction is measured by the measuring part. Here, In
cases where a reagent is not used, no reagent is introduced.
[0058] In a typical case according to the embodiment, the water
sample is drinking water distributed by a water distribution system
and a reagent such as DPD or orthotolidine reacting with chlorine
and causing color development. Moreover, washing water such as
dilute chloric acid, neutral detergent, etc.; and reference water
such as pure water, calibration water, etc. are selected as liquid
86 in the cartridge 80 and liquid 89 in the cartridge 81,
respectively. The water sample, the reagent, the washing water, and
the reference water are introduced to the corresponding analyzing
cells at a predetermined interval using a sequence control method.
In the above case, the analyzing cells 76, 77, and 78 are used as a
residual chlorine concentration meter, a chromaticity meter, and a
turbidity meter, respectively. The reagent liquid 82 is introduced
only to the analyzing cell 76 allocated as the residual chlorine
concentration meter.
[0059] Naturally, a measurement category can be changed by changing
the type of reagent, and the allocation of each analyzing cell to
some one of the required measurement categories is optional.
[0060] In the residual chlorine concentration meter, the degree of
color development due to the reaction of the water sample and the
reagent is measured by an absorptiometric method. In the
chromaticity meter, a reagent is not used, and the absorbance of
water sample is measured. However, since the absorbance of the
water sample is low, a comparison measurement method is adopted
using the reference water (pure water), and a base level of the
zero absorbance is calibrated for a predetermined period. As for
the turbidity meter, neither reagent nor reference water is used,
but impurity particles are counted. Further, the total number is
converted to the turbidity value.
[0061] Moreover, if an analyzing cell with electrodes is used, the
conductivity or pH of the water sample can be measured without
changing the structure of the analyzing cell.
[0062] A predetermined quantity of the washing water liquid 86 is
introduced to each analyzing cell at prescribed time intervals, and
washes the fluid flow paths in the analyzing cell, the electrodes,
and so on. Substances washed out from the analyzing cells are
expelled from the mixing and analyzing unit 110 along with the
water sample 71 or the reference water 89.
[0063] Here, although one cartridge is used for the reagent in this
embodiment, a plurality of cartridges can be provided for reagents,
and various types of reagent can be used for the different
measurement categories for which a reagent is necessary, by using a
selection valve, for example.
[0064] In the following, details of the structure of each of the
analyzing cells 76, 77, and 78 shown in FIG. 4 will be explained
with reference to FIG. 7 and FIG. 8. Although only the analyzing
cell 76 is explained below, the structure of the other cells 77 and
78 are the same as that of the cell 76, and explanations for the
structures of the cells 77 and 78 have therefore been omitted.
[0065] Although the principle of measurement performed in each
analyzing cell is different from those of the other analyzing cell
(the absorptiometry for a predetermined wavelength is carried out
in the residual chlorine concentration meter and the chromaticity
meter, and a fine particle number coefficient method is adopted for
the turbidity meter. Moreover, the conductivity or pH can be
measured by using an analyzing cell with electrodes.), the
analyzing cells have a module composition in which both the size
and shape, and the arrangement of the internal fluid flow paths,
are common among the analyzing cells. Although the three analyzing
cells are detachably attached to the upper surface of the mother
board 101 in this embodiment, the number of analyzing cells is not
restricted to three. That is, by changing the arrangement of the
internal fluid flow paths in the analyzing cells, the number of
analyzing cells mounted on the mother board 101 can be freely
changed. Also, the arrangement of the analyzing cells is arbitrary.
By selecting a liquid or a reagent for an analyzing cell according
to a measurement category, and setting a measurement sequence, it
is possible to set the analyzing cell to perform a required
measurement function.
[0066] In another example, all of the analyzing cells can be set so
as to measure the same measurement category. By setting a plurality
of analyzing cells measuring the same measurement category on the
mother board 101, the reliability of the measurement for that
category can be improved. Accordingly, even if a malfunction occurs
in one of the analyzing cells, the measurement can be continued by
using the remaining normal cells, which can extend the life time of
the total monitoring system.
[0067] As shown in FIG. 7, each analyzing cell is composed of the
reagent mixing part 201 (flow cell substrate 325) and the measuring
part 202 ( measurement cell substrate 209). The structure of the
reagent mixing part (flow cell substrate 325) is explained in
detail below with reference to FIG. 8. The flow cell substrate 325
has a duplex layered structure of a silicon substrate 301 and a
Pyrex glass cover 302, and is fabricated by the micro-fabrication
technique. An S-shaped fluid flow path 305, an inclined face 303
and a flat bottom face 304 are formed in the substrate 301 by
shaping a wafer of highly pure silicone using an anisotropic
etching. Furthermore, a plurality of rectangular penetrating holes
306, 307, 308, and 309, and a mesh-type hole 310 in which fine
holes with a diameter of several micrometers are formed in a mesh
state with a pitch of 100-200, .mu.m, are also on the back side of
the substrate 301. All of the holes 306-310 are connected to the
fluid flow path 305. Moreover, the cover 302 is connected to the
upper surface of the substrate 301 by an anodic bonding method. The
substrate 301 and the cover 302 are connected to each other to
which a predetermined voltage is applied at a high temperature in a
vacuum state in a wafer size. Afterward, the wafer is cut to as a
required size for use. The usage size, which depends on the shape
of the flow path 305, is about 1 cm.times.2 cm.
[0068] One of the various types of liquid (water sample 71, reagent
82, washing water 86, and reference water 89) is selected and fed
to each agent mixing part 201 (flow cell substrate 325), by
selectively driving the electromagnetic valves and the pumps
attached to the side faces of the mother board 101. In this
embodiment, the reference water 89, the washing water 86, water
sample 71, and the reagent 82 are fed to the holes 306, 307, 308,
and 310, respectively. The liquid flows in the flow path 305, is
introduced to the straight path 311, and finally expelled to the
outside of the analyzing cell.
[0069] Here, in this embodiment, the liquids from the cartridges
are injected to the penetrating holes so that at the further
upstream the position in the fluid flow path, the cleaner (purer)
the water that flows. By the above liquid injection method, the
whole of the flowpath 305 can be cleaned. In addition, by filling
the flow path 305 with the cleanest water, for example, the
reference (pure) water, when measurements are not being made, and
introducing the other liquid only for measurements, the degradation
of measurement sensitivity due to the contamination of the flow
paths 305 can be prevented.
[0070] Furthermore, all of the various types of liquid flow in
different paths each in the mother board 101. That is, the various
types of liquid are separately fed to the flow cell substrate 325,
and never mixed until the liquid enters the flow path 305 in which
a measurement such as the absorbance measurement is executed.
Therefore, since the mixing of the various types of liquid occurs
just before the measurement, the contamination of the flow paths in
the mother board 101 due to the mixing of the various types of
liquid is kept as low as possible, which can result in highly
accurate measurements.
[0071] Next, the measuring part 202 (measurement cell substrate
209) will be explained. A light emitting element 203 such as an
LED, a laser diode, etc., a lens system for converging a light beam
emitted from the light emitting element 203 at the inclined face
303 in the straight path 311, and a light detecting element 205 for
monitoring changes in the quantity of the light beam are arranged
in the measurement part 202. The converged light beam 206 which has
been transmitted through the straight path 311 is reflected by the
inclined face 303' opposite to the inclined face 303, and returns
to the measurement part 202. The light beam which has returned to
the measurement part 202 is measured by a light detecting element
208 provided in the measurement part 202. The light emitting
element 203, the light detecting elements 205 and 208, the lens
system 204, and the straight path 311 are attached to the
measurement cell substrate 209 so that their relative positions are
fixed. Further, the measurement cell substrate 209 is detachably
attached to the mother board 101.
[0072] Although explanations for the other analyzing cells for the
chromaticity and the turbidity are omitted, for these cells, the
shape and size of the analyzing cells 76-78 are common, as is the
arrangement of flow paths.
[0073] The residual chlorine concentration meter for which the
analyzing cell 76 is used is explained below. In this residual
chlorine concentration meter, while the washing water 86 and the
reference water 89 are not fed, the water sample 71 and the reagent
82 are fed to the concentration meter at a predetermined ratio, and
mixed in the flow path 305. Here, the reagent 82 is injected into
the water sample through the mesh-type hole 310. By passing the
reagent 82 through the mesh-type hole 3 10, the reagent 82 can be
homogeneously injected into the water sample, which will enable the
reagent 82 to diffuse in the water sample for a short time.
Accordingly, the color development reaction of the water sample 71
and the reagent 82 is quickly completed with the degree of color
development being proportional to the residual chlorine
concentration. The mixture of the water sample 71 and the reagent
82 in which the color development reaction has been completed is
introduced to the straight path 311, and the degree of color
development is measured by the absorptiometric method. While
measuring the absorbance of the mixture, the flow of the mixture is
temporarily stopped so as to stabilize the measured value. After
the measurement, the measured mixture 312 is expelled through the
penetrating hole 309. When calibrating the sensitivity for or the
zero point of the degree of color development proportional to the
residual chlorine concentration, the reference water 89 whose
chlorine concentration was measured in advance is fed into the
analyzing cell 76, and the degree of color development is measured
using the above-explained procedures. This measured value for the
degree of color development is used as the reference value to
correct the measured values for the degree of development. The
washing water 86 is fed into each analyzing cell to wash and remove
mineral or plant contaminants in its reagent mixing part
(especially in the straight path 311) corresponding to the grade of
contamination.
[0074] Here, in the structure of the analyzing cell according to
the present invention, if fine extraneous substances or bubbles
adhere to the inside of the flow path 311, the quantity of the
light beam 206 transmitting through the path 311 changes
considerably, which makes it impossible to correctly measure the
absorbance of the mixed liquid. Since the fine extraneous
substances or bubbles are very small, and adhere to many different
locations, all of the extraneous substances or bubbles cannot
removed by the usual procedure of washing the flow paths in each
analyzing cell. In the present invention, a plurality of washing
liquid feeding patterns other than the usual washing liquid feeding
procedure is prepared, and any one of the patterns can be
selected.
[0075] The prepared washing liquid feeding patterns are as
follows.
[0076] (1) The water sample 71 is fed as the washing liquid. That
is, since the pump 74 for feeding the water sample 71 is a metering
pump, this pump can feed the washing liquid using high pressure
although the flow rate of the washing liquid has a definite value.
The fine extraneous substances and bubbles are removed by the water
sample 71, which is fed at a higher pressure than a water sample
fed for a usual measurement.
[0077] (2) The washing water 87 and/or the reference water 81 is
fed as the washing liquid. That is, since the pumps for feeding the
washing water 87 and the reference water 81 are diaphragm pumps,
and feed liquid with a pulsating flow, the fine extraneous
substances and bubbles are removed by the pulsating flow.
[0078] (3) The washing water 86 (which is more effective if it
includes surfactant) is fed to the straight path 311, and remains
there for a time. Afterward, the path 311 is washed by the water
sample 71. This pattern is effective for contaminant which cannot
be removed by a change in the flow rate, as in pattern (2).
[0079] In accordance with the present invention, the fine
extraneous substances and bubbles can be removed by using one or a
combination of the above washing liquid feeding patterns, which can
provide a more reliable water quality meter. Moreover, the washing
liquid feeding pattern can be designated from the water quality
control center 3 by a remote transmission.
[0080] In FIG. 9, another water quality monitoring system of a
composition different from that of the system shown in FIG. 3 is
shown. In the embodiment shown in FIG. 9, the water meter 9 and the
water quality meter are integrated. Since the water quality meter
according to the present invention can, by adopting the
micro-fabrication technique, be made smaller while retaining the
ability of to measure a plurality of measurement categories, the
water quality meter can be incorporated into the water meter 9. The
water distributed to each end user flows through the water meter 9
via the water supplier side sub-pipe 6 and the shut off valve 10,
and the flow rate of the water is measured by the meter 9.
Simultaneously, part of the water is fed into the water quality
meter 8 via a water sample-introducing pipe 24. According to this
composition, the integrated water meter and water quality meter are
contained in the box for the water meter 9, and can be attached to
a water distribution pipe for the end user. Thus, a special space
and/or an special attachment labor for the water quality meter
become unnecessary, and the integrated water meter and water
quality meter can be as easily attached as a conventional water
meter.
[0081] In FIG. 10, another water quality monitoring system of a
composition different from that of the system shown in FIG. 9 is
shown. In the embodiment shown in FIG. 10, power fed to the water
quality meter is generated in the system itself with solar
batteries. The power generated by the solar batteries is fed to the
water quality meter via a diode 22, and surplus power is stored in
a storage battery 23. If the sunlight energy is not obtained at
night or on a rainy day, the storage battery 23 backs up power
supplied to the water quality meter by discharging the stored
energy. The diode 22 is provided as a protection means for
preventing a reverse current flow to the solar batteries 21 when
discharging energy from the storage battery 23. According to the
above composition, by selecting the proper capacity for the solar
batteries 21 and that for the storage, battery 23, an autonomous
operation of the water quality meter without external power becomes
possible. Equipment or labor to secure AC power is not necessary,
which can remove the limitation for selecting the location of the
water quality meter and reduce the cost of fabrication.
[0082] Since the above-explained water quality meter 8 is located
at the house of each end user, the control center 3 can control the
quality of water distributed to each end user. In another example,
the water quality meters are located at houses at a ratio of one to
thirty-plus houses, which can reduce the quantity of transmitted
data between the control center 3 and the water quality meters to
one thirtieth or less of the original volume, and greatly reduce
the load of data processing in the control center 3. Furthermore,
it becomes possible to control the quality of water distributed to
end users with the remarkably higher accuracy than a conventional
system which can control the quality of water at the end user side
only at a ratio of one to several hundreds of thousands of
houses.
[0083] Furthermore, since the size of the water quality meter 8
according to the present invention has been considerably decreased
with the micro-fabrication technique, the quantity of the water
sample or reagent used for the water quality measurements can be
reduced to a level of micro-litters. Accordingly, the time interval
for refills of the reagent, washing water, etc. can be extended by
more one month even with continuous measurements.
[0084] The above embodiments are summarized as follows.
[0085] (1) The water quality meter according to the present
invention is set at the end side part of the water distribution
piping network, near or in the house of each end user, and a
control center performs collective water quality control based on
information transmitted from each water quality meter.
[0086] (2) The water quality meter is set in a manhole, a fire
hydrant, a water meter box, a utility (for example, under a drain
in the house of an end user), etc. Thus, the possibility that
ordinary people might touch the water quality meter is decreased,
and so the safety can be assured.
[0087] (3) The sample inlet unit, the reagent mixing part, and the
measuring part, which generally increase the size of a measurement
apparatus, are made much smaller by adopting the micro-fabrication
technique. The size of the water quality meter can be decreased to
one-thousandth of that of a conventional water quality meter by
using the presently developed micro-fabrication technique.
[0088] (4) The three-dimensional fluid flow paths in the analyzing
cell are formed by using ultraviolet-curing-type plastic, which can
make possible a tubeless structure. Thus, the mixing and analyzing
unit can be made smaller, and the reliability of the unit can also
be improved.
[0089] (5) The fabrication and an installation cost of the water
quality meter are decreased by making the meter smaller, and since
the micro-fabrication technique is used in the silicon
semiconductor element processing, the fabrication cost can be
greatly decreased even further by mass-producing water quality
meters according to the present invention.
[0090] (6) The quantity of liquid used for the water quality
measurement can be reduced to a level of micro-litters because the
size of the water quality meter is very small. Thus, the period for
refills of the reagent can be extended by more one month even if
the measurements are continuously performed. Moreover, the quantity
of exhaust water is very small, and if an exhaust water withdrawal
and collection, or evaporation method is adopted, the installation
of exhaust water equipment is not necessary.
[0091] (7) The reagent, the reference water, and so on, which are
consumed in the measurements, are each stored in cartridges and fed
to the analyzing cells each, which can make refilling them very
easy.
[0092] (8) The decrease in size of the water quality meter also
greatly decreases its power consumption. Thus, a built-in battery
or a solar battery can be used as a power source, and transmission
wiring also becomes unnecessary by using a radio circuit as a
signal transmission means.
[0093] (9) The composition of the fluid flow paths is such that the
various types of liquid to be used are not mixed before reaching
each analyzing cell, which can prevent contamination in the flow
paths. Furthermore, a plurality of penetration holes for
introducing various types of liquid each are formed in a flow path
in each analyzing cell, and these various types of liquid are
introduced from the respective penetration holes so that the
further upstream the position in the fluid flow path, the cleaner
the liquid (the purer the water) that flows, which can suppress
contamination in the flow path in the analyzing cell.
[0094] (10) Since it is assumed that fine extraneous substances or
bubbles will adhere to the inside surface of the flow path in the
analyzing cell if a comparatively large variation occurs in the
results of the measurement, one of a variety of prepared washing
liquid feeding patterns other than the usual washing water feeding
procedure is selected and executed to remove the fine extraneous
substances or bubbles.
[0095] In accordance with the present invention, the effects
described below can be expected.
[0096] (1) Since a water quality meter with a size of
one-thousandth of that of a conventional water quality meter can be
provided, the flexibility in the installation of the meter can
improved.
[0097] (2) Since a water quality meter of a small size and minimal
power consumption can be achieved, it is possible to construct an
on-line water quality monitoring system which can measure a
plurality of measurement categories without wiring by using a
battery as a power source and a radio transmission means.
[0098] (3) By adopting a module structure for the analyzing cells,
the selection, combining, or changing of the measurement categories
is easy, which enables it to be more flexible in responding to
changes in the measurement sequence.
[0099] (4) By applying a photo-forming method using
ultraviolet-curing in the formation of three-dimensional fluid flow
paths with three-dimensional CAD data of the flow paths, the
three-dimensional fluid flow paths can be formed without using a
mold, by which the water quality meter can be cheaply and quickly
fabricated.
[0100] (5) Since a micro-sized sampling and analyzing unit can be
fabricated, the quantity of liquid needed for the water quality
measurement is reduced, which can considerably extend the time
interval for refills of the liquid.
[0101] (6) Since various types of liquid to be used for the
measurement are not mixed until just before the measurement is
performed, the contamination of the internal fluid flow paths can
be prevented, which can greatly improve the accuracy of the water
quality measurement.
[0102] As explained above, in accordance with the present
invention, it is possible to provide a micro-sized water quality
meter with a high reliability, and a water quality monitoring
system using the water quality meter.
[0103] Speaking in greater detail, since a water quality meter has
a size of one-thousandth of that of a conventional water quality
meter can be provided, it is possible to provide a water quality
meter of a very small size and a low water sample flow rate.
Accordingly, the water quality meter can be driven by an internal
battery, and continuous measurements over a long period are
possible with a only small quantity of reagent. Therefore, special
wiring and piping are not necessary to install the water quality
meter, which can greatly reduce the installation cost. Thus, the
water quality monitoring system can be very easily constructed.
[0104] Furthermore, since the analyzing cells have a common module
structure, it is possible to realize a water quality meter for a
variety of measurement categories, in which there is a great deal
of freedom in the selection and combination of the measurement
categories.
* * * * *