1. A pressure-type filtration device comprising: a plurality of filtration chambers each of which has filtering 5 material therein and which are arranged concentrically; a raw water distribution part which is arranged at a center part of the plurality of filtration chambers in a plan view and to which raw water to be filtered is supplied from the outside; a flow channel system which connects raw water introducing 10 ports of the plurality of filtration chambers and the raw water distribution part and is capable of attaining a first state and a second state, the first state being a state in which the raw water in the raw water distribution part is distributed to the raw water introducing ports of the plurality of filtration chambers, and the 15 second state being a state in which a raw water introducing port of a backwash target filtration chamber and a waste water pipe are connected and raw water in the raw water distribution part is distributed to the raw water introducing ports of the filtration chambers other than the backwash target filtration chamber; and 20 a purified water chamber into which filtered water from the filtered water outlets of the plurality of filtration chambers flows, and which act as a filtered water path which guides the filtered water from the plurality of filtration chambers other than the backwash target filtration chamber to the filtered water outlet 25 of the backwash target filtration chamber.

2. The pressure-type filtration device according claim 1, wherein the plurality of filtration chambers, the raw water distribution part and the purified water chamber are provided in 30 a filtration body, and the plurality of filtration chambers have shapes formed by equally dividing an inner part of the filtration body excluding the raw water distribution part and the purified water chamber along radial directions from the center of the filtration body. 29 􀀃

3. The pressure-type filtration device according claim 1, wherein the flow channel system includes discrete channel systems which are provided to each filtration chamber and each of which has 5 one or more valve devices to alternatively connect the raw water introducing port of the filtration chamber to the raw water distribution part and the waste water pipe.

4. The pressure-type filtration device according claim 2, 10 wherein the filtration body is circular in cross-section view.

The present invention relates to a pressure-type filtration
5 device.
[Background]
[0002] A pressure-type filtration device (closed type
filtration device) is known as a filtration device to purify water
10 by filtering raw water. In order to keep performance of the
pressure-type filtration device, it is necessary to periodically
perform water discarding which is for cleaning of filtering material
and for stabilization of filtering material particles. One of the
washing methods of filtering material is backwashing.
15 [0003] A system (see e.g., PTL1) has been therefore developed
which includes a plurality of pressure-type filtration devices and
which is configured in such a manner that each pressure-type
filtration device can be backwashed by filtered water obtained by
the other pressure-type filtration devices.
20 [Citation List]
[Patent Literature]
[0004]
[PTL 1] Japanese patent laid-open publication No. 2003-93808.
25 [Summary]
[Technical Problem]
[0005] To the above-described system, configuration is
adopted in which a plurality of pressure filters that are arranged
in a line are connected by a plurality of header pipes (raw water
30 main pipe, communication pipes, etc.). However, with the
configuration, it is difficult to approximately uniform quantity
of raw water to be supplied to each pressure filter device in the
filtration step.
[0006] It is therefore the object of the present invention to
2
􀀃
provide a pressure-type filtration device, which includes a
plurality of filtration chambers, where each filtration chamber can
be cleaned individually and quantity of raw water to be supplied
to each filtration chamber in the filtration step can be made
5 approximately uniform.
[Solution to Problem]
[0007] To accomplish the above object, a pressure-type
filtration device according to the present invention comprises: a
plurality of filtration chambers each of which has filtering
10 material therein and which are arranged concentrically; a raw water
distribution part which is arranged at a center part of the plurality
of filtration chambers in a plan view and to which raw water to be
filtered is supplied from the outside; a flow channel system which
connects raw water introducing ports of the plurality of filtration
15 chambers and the raw water distribution part and is capable of
attaining a first state and a second state, the first state being
a state in which the raw water in the raw water distribution part
is distributed to the raw water introducing ports of the plurality
of filtration chambers, and the second state being a state in which
20 a raw water introducing port of a backwash target filtration chamber
and a waste water pipe are connected and raw water in the raw water
distribution part is distributed to the raw water introducing ports
the filtration chambers other than the backwash target filtration
chamber; and a purified water chamber into which filtered water from
25 the filtered water outlets of the plurality of filtration chambers
flows, and which act as a filtered water path which guides the
filtered water from the plurality of filtration chambers other than
the backwash target filtration chamber to the filtered water outlet
of the backwash target filtration chamber.
30 [0008] Namely, the pressure-type filtration device of the
present invention has such configuration that the plurality of
filtration chambers are arranged concentrically centering on the
center part of the raw water chamber. Therefore, "the channel
system" in the pressure-type filtration device of the present
3
􀀃
invention can be designed and manufactured easily so that the
channel resistance of the raw water channel between each filtration
chamber and the raw water chamber becomes approximately equal.
Accordingly, by adopting the above configuration, it is possible
5 to easily realize the pressure-type filtration device where
quantity of raw water to be supplied to each filtration chamber in
the filtration step is approximately uniform.
[0009] Note that the plurality of filtration chambers in the
pressure-type filtration device of the present invention are not
10 necessarily arranged in a perfect circle so long as they are arranged
concentrically. Therefore, the pressure-type filtration device of
the present invention may be realized as an device where distances
between some filtration chambers and the raw water distribution part
are longer/shorter than distances between the other filtration
15 chambers and the raw water distribution part. Further, the
plurality of filtration chamber in the pressure-type filtration
device of the present invention are not necessarily arranged with
a constant angular space. Therefore, the pressure-type filtration
device of the present invention may be realized, for example, as
20 an device of which filtration chambers are arranged in an
approximately semicircular shape.
[0010] As the channel system in the pressure-type filtration
device of the present invention, various systems with different
specific configurations can be adopted. For example, it is possible
25 to adopt the channel system which includes discrete channel systems
which are provided to each filtration chamber and each of which has
one or more valve devices to alternatively connect the raw water
introducing port of the filtration chamber to the raw water
distribution part and the waste water pipe.
30 [0011] To reduce the size, the pressure-type filtration device
of the present invention may be realized as the device "wherein the
flow channel system includes discrete channel systems which are
provided to each filtration chamber and each of which has one or
more valve devices to alternatively connect the raw water
4
􀀃
introducing port of the filtration chamber to the raw water
distribution part and the waste water pipe." Note that, when this
constitution is adopted, it is desirable to adopt the filtration
body, the cross section shape of which is polygonal or circular.
5 [0012] Further, the pressure-type filtration device of the
present invention may be realized as the device "wherein the channel
system is one valve device which is capable of attaining the first
state and the second state by moving a valve element in a valve box."
[0013] The number of the filtration chambers of the
10 pressure-type filtration device of the present invention and the
number of the filtration chambers to be backwashed (backwash target
filtration chambers) are not particularly limited. It is available
to determine the number of the filtration chambers and the number
of the filtration chambers to be backwashed from a backwashing step
15 flow velocity which is defined as a flow velocity required to
backwashing and a filtering speed. For example, when the filtration
speed is 200 m/day and the backwashing flow velocity is 1,000 m/day,
the number of the filtration chamber may be six and the number of
the filtration chambers to be backwashed may be one. Further, when
20 the filtration speed is 300 m/day, and the backwashing flow velocity
is 900 m/day, the number of filtration chambers may be four and the
number of filtration chambers to be backwashed may be one.
Moreover, when the filtration speed is 120-150 m/day, and the
backwashing flow velocity is 840-1050 m/day, the number of
25 filtration chambers may be eight and the number of filtration
chambers to be backwashed may be one.
[0014] Further, when the backwashing step flow velocity is
almost twice of the filtration flow quantity, the number of
filtration chambers may be three and the number of filtration
30 chambers to be backwashed may be one, or also the number of filtration
chambers may be six and the number of filtration chambers to be
backwashed may be two.
[Advantageous Effects of Invention]
5
􀀃
[0015] According to the present invention, it is possible to
easily realize the pressure-type filtration device where quantity
of raw water to be supplied to each filtration chamber in the
filtration step is approximately uniform.
5
[Brief Description of Drawings]
[0016]
FIG. 1 is a top plan view of the pressure-type filtration
device according to a first embodiment of the present invention.
10 FIG. 2 is a front view of the pressure-type filtration device
according to the first embodiment.
FIG. 3 is an explanatory drawing of the internal structure
of the pressure-type filtration device according to the first
embodiment.
15 FIG. 4 is a sectional view of the selector valve cut by a plane
passing through the center of the selector valve.
FIG. 5A is a plane view of a valve element in the selector
valve.
FIG. 5B is a side view of the valve element.
20 FIG. 6 is a development view of a shaft part which is a
component of the selector valve.
FIG. 7 is an explanatory drawing of position relations that
the valve element and the raw water outlet of the selector valve
can take.
25 FIG. 8 is a section view of the valve element along the
VIII-VIII line of Fig.7 viewing from the arrow direction.
FIG. 9 is an explanatory drawing of the constitution of the
selector valve.
FIG. 10A is an explanatory drawing of paths of raw water and
30 so on in the filtration step of the pressure-type filtration device
according to the first embodiment.
FIG. 10B is an explanatory drawing of paths of raw water and
so on in the backwashing step of the pressure-type filtration device
according to the first embodiment.
6
􀀃
FIG. 10C is an explanatory drawing of paths of raw water and
so on in the water discarding step of the pressure-type filtration
device according to the first embodiment.
FIG. 11 is a sectional view of the pressure-type filtration
5 device according to a second embodiment of the present invention.
FIG. 12 is a top plan view of the pressure-type filtration
device according to the second embodiment.
FIG. 13 is an explanatory drawing of the raw water paths and
so on in the filtration step of the pressure-type filtration device
10 according to the second embodiment.
FIG. 14 is an explanatory drawing of raw water paths and so
on in the backwashing step of the pressure-type filtration device
according to the second embodiment.
FIG. 15 is an explanatory drawing of raw water paths and so
15 on in the water discarding step of the pressure-type filtration
device according to the second embodiment.
FIG. 16A is a plane view to explain a variation of the valve
element in the selector valve of the pressure-type filtration device
according to the first embodiment.
20 FIG. 16B is an explanatory drawing of the constitution of the
valve element shown in FIG. 16A.
FIG. 17 is an explanatory drawing of a variation of the
pressure-type filtration device according to the second embodiment.
FIG. 18 is an explanatory drawing of other variations of the
25 pressure-type filtration device according to the second embodiment.
[Description of Embodiments]
[0017] The embodiments will now be described with reference
to the accompanying drawings.
30 [0018] <>
FIG. 1 is a top plan view of a pressure-type filtration device
1 according to a first embodiment of the present invention.
Further, FIG. 2 is a front view of the pressure-type filtration
device 1 and FIG. 3 is an explanatory drawing of the internal
7
􀀃
structure of the pressure-type filtration device 1.
[0019] The pressure-type filtration device 1 according to the
present embodiment is a pressure-type filtration device to which
the principle of the self-backwashing equipment is applied. As
5 illustrated in FIGs, 1 through 3, the pressure-type filtration
device 1 comprises a filtration device main body 10, a raw water
pipe 20, filtered water pipes 22a - 22c, a water discarding pipe
23, and so on.
[0020] The raw water pipe 20 (FIG. 3) is a pipe to supply water
10 to be purified by the filtration device main body 10 (which will
be denoted hereinafter as raw water) to the filtration device main
body 10. The filtration device main body 10 is a device that filters
raw water supplied through the raw water pipe 20 and output
filtration result of raw water (which will be denoted hereinafter
15 as filtered water) from a filtered water outlet 22d (FIG. 2) which
is an open end of the filtered water pipe 22a. As illustrated in
FIGS. 1 and 3, in the filtration device main body 10, a raw water
chamber 11, six filtration chambers 12 and a purified water chamber
13 are arranged. Moreover, a selector valve 30 is attached to the
20 central part of the upper surface central part of the filtration
device main body 10.
[0021] The selector valve 30 is a six-way valve that is
developed for the pressure-type filtration device 1 (the filtration
device main body 10). As illustrated in FIG. 3, the selector valve
25 30 is formed by a selector valve body part 30a that is housed in
an outer shell 10a of the filtration device main body 10 and a drive
part 30b that protrudes from the outer shell 10a.
[0022] The selector valve body part 30a is a unit (valve device)
where a cylindrical valve element 40 moves vertically and rotates
30 in a cylindrical valve box having an upper lid and a bottom lid.
As shown in FIG. 3, at the upper part of the side surface of the
valve box of the selector valve body part 30a, six raw water inlets
32a are arranged with a constant angular space. Further, at the
part of the side surface of the valve box of the selector valve body
8
􀀃
part 30a lower than each raw water inlet 32a, six raw water outlets
32b are arranged with a constant angular space. Moreover, an
opening 32c, which acts as an outlet of washing waste water (details
will be discussed later), is formed on the lower surface of the
5 selector valve body part 30a, and the opening 32c is connected to
a waste water pipe 24 extending vertically downward to the outside
of the outer shell 10a of the filtration device main body 10.
[0023] Before explaining the details of the selector valve 30
(the selector valve body part 30a and the drive part 30b),
10 constitution of the pressure-type filtration device 1 other than
the selector valve 30 will be discussed.
[0024] The raw water chamber 11 (FIG. 3) is a part (vessel)
into which raw water is supplied through the raw water pipe 20. The
shape of the raw water chamber 11 (shapes of partitions which are
15 components of the raw water chamber 11 and to which the selector
valve body part 30a is fitted, and so on) is determined in such a
manner that the raw water inlet 32a of the selector valve body part
30a acts as an outlet of the raw water supplied through the raw water
pipe 20. Furthermore, it is determined that only six raw water
20 outlet 32b of the selector valve body part 30a are act as outlets
of raw water supplied to the selector valve body part 30a from the
raw water inlets 32a.
[0025] Each filtration chamber 12 (FIG. 3) is a unit where
filtering material 12a is arranged on a water collection board 15
25 (partition plate formed by strainer and the like for supporting the
filtering material 12a, collecting filtered water and scattering
backwashing water). Note that, the filtration chamber 12 according
to the present embodiment is a unit of which the water collection
board 15 functions as the filtered water outlet. Further, although
30 anthracite, manganese sand and filtration gravel are depicted as
the filtering materials 12a in FIG. 3, the filtering material 12a
is for removing impurities included in raw water, and, kind,
particle diameter and uniformity coefficient of the filtering
material 12a are determined based on components and density of the
9
􀀃
removal object.
[0026] As illustrated in FIG. 1, each filtration chamber 12
has shape obtained by the shape dividing the principal part of the
inner space of the filtration device main body 10 (outer shell 10a)
5 into six in radial directions from the center of the filtration
device main body 10. The selector valve 30 is attached to the
filtration device main body 10 in such a manner that raw water can
be supplied to each filtration chamber 12 through only corresponding
raw water outlet 32b.
10 [0027] The purified water chamber 13 (FIG. 3) is space in the
filtration device main body 10 lower than water collection boards
15 in six filtration chamber 12 . As shown in the Figure, In the
purified water chamber 13, one end of a filtered water pipe 22b is
inserted which extends to the lower surface of the selector valve
15 body part 30a in the form of accommodating the waste water pipe 24
therein. To the part of this filtered water pipe 22b higher than
the upper surface of the filtering material 12a, one end of a filtered
water pipe 22c which extends approximately horizontally to the
outside of the outer shell 10a of the filtration device main body
20 10 is connected. A filtered water pipe 22a is connected to the other
end of the filtered water pipe 22c, and the filtered water supplied
to the purified water chamber 13 from each filtration chamber 12
passes the filtered water pipes 22b, 22c and 22a in this order and
then flows out from the filtered water outlet 22d.
25 [0028] Note that, purpose of raising the filtered water to a
position above the upper surface of the filter material 12a before
flowing out the filtered water is so that there is an amount of water
covering the filter material 12a In each filtration chamber 12, even
if a supply of raw water decreases by some kind of factors.
30 [0029] As illustrated in FIG. 2, at a part of the filtered water
pipe 22a near the filtered water outlet 22d, a filtered water valve
27 to permit or stop the outflow of filtered water from the filtered
water outlet 22d is arranged. The filtered water pipe 22a is
connected to the waste water pipe 24 in the part upstream from the
10
􀀃
filtered water valve 27 via the water discarding pipe 23. The water
discarding valve 28 is mounted on the way of the water discarding
pipe 23, which is opened when filtered water flowing within the
filtered water pipe 22a is drained from the waste water pipe 24.
5 [0030] Constitution of the selector valve 30 will be described
with reference to FIGS. 4 to 8. Note that, FIG. 4 is a sectional
view of the selector valve 30 cut by a plane passing through the
center of the selector valve 30. However, hatching is omitted in
this sectional view. (A) and (B) in FIG. 5 are a plane view and
10 a side view of the valve element 40, respectively. FIG. 6 is a
development view of a shaft part 60 which is a component of the
selector valve 30. FIG. 7 is an explanatory drawing of position
relations that the valve element 40 and the raw water outlet 32b
of the selector valve can take, and FIG. 8 is a section view of the
15 valve element 30 along the VIII-VIII line of Fig. 7 viewing from
the arrow direction. FIG. 9 is an explanatory drawing of the
constitution of the selector valve 30.
[0031] As illustrated in FIG. 4, the selector valve 30 is
divided into a selector valve body part 30a and a drive part 30b
20 by an isolation plate 38.
[0032] To start with, constitution of the selector valve body
part 30a is described. The selector valve body part 30a comprises
the isolation plate 38, a housing 31, the valve element 40 and so
on.
25 [0033] The housing 31 is a member functioning as a valve box
of the selector valve body part 30a by being fixed to the isolation
plate 38.
[0034] At the upper part of the side surface of the housing
31, six circular raw water inlets 32a having the same diameter are
30 arranged with a constant angular space. At the part of the housing
31 lower than the each raw water inlet 32a, six circular raw water
outlets 32b having the same diameter are arranged with a constant
angular space. The diameter of this raw water outlet 32b is bigger
than the diameter of the raw water inlet 32a (in the present
11
􀀃
embodiment approximately 2.5 times of the diameter of raw water
inlet 32a). Further, the housing 31, as shown in the Figure, has
the shape that allows the valve element 40 therein to be lowered
down to a position where the top surface is lower than the lower
5 end of each raw water outlet 32b.
[0035] The valve element 40 is a member having a shape shown
in FIG. 5 (A) and 5(B). That is, the valve element 40 is a
substantially columnar member. Further, five raw water channels
41a communicating between the top and side surfaces of the valve
10 element 40 and a washing waste water channel 41b communicating
between the bottom and side surfaces of the valve element 40 are
formed in the valve element 40. Hereinafter, the openings of the
raw water channel 41a on the side surface and on the top surface
of the valve element 40 are referred to as the side surface opening
15 and the upper surface opening of the raw water channel 41a,
respectively. Similarly, the openings of the washing waste water
channel 41b on the side surface and on the top surface of the valve
element 40 are referred to as the side surface opening and the upper
surface opening of the washing waste water channel 41b,
20 respectively.
[0036] Each raw water channel 41a formed in the valve element
40 is a channel having approximately the same diameter (in diameter)
as the raw water inlet 32a. Further, five raw water channel 41a
are in the same shape as shown in FIGs 5(A) and 5(B).
25 [0037] The washing waste water channel 41b formed in the valve
element 40 is a channel the cross sectional area of which is larger
than that of the raw water channel 41a (in the present embodiment,
a circular channel the diameter of which is substantially 2.5 times
larger than that of the raw water channel 41a). The six channels
30 (five raw water channels 41a and one washing waste water channel
41b) in the valve element 40 are formed in such a manner that center
intervals between every two adjacent side surface openings are
equiangular intervals (that is, 60 degrees intervals). Further,
on the side surface of the valve element 40, O-ring grooves (which
12
􀀃
has dovetail groove shape) each surrounding the surface side opening
are formed, and the valve element 40 is placed within the housing
31 in a condition where an O-ring is inserted in each O-ring groove.
[0038] As illustrated in FIG, 4, a stem 45 for rotating and
5 vertically moving the valve element 40 in the housing 31 is provided
at the center part of the valve element 40. The stem 45 extends
into the drive part 30b through an opening (bearing part) of the
isolation plate 38, and the opening of the isolation plate 38 is
configured in such a manner that allows the stem 45 to be rotated
10 and vertically moved while ensuring watertightness and
airtightness.
[0039] Hereinafter, the drive part 30b of the selector valve
30 will be described. The drive part 30b of the selector valve 30
is a unit for vertically moving and rotating the valve element 40
15 in the selector valve body part 30a (housing 31). As shown in FIG.
4, the drive part 30b comprises a housing 50, a piston 53 and a shaft
part 60.
[0040] The housing 50 is formed by a cylindrical cylinder part
52 and a top cover 51 covering the upper end of the cylinder part
20 52, and so on. The top cover 51 is provided with a compressed air
introducing port 51a from which compressed air is introduced when
the piston 53 is moved downward. Further, the isolation plate 38
constituting the bottom surface of the drive part 30b is provided
with a compressed air introducing port 38a from which compressed
25 air is introduced when the piston 53 is moved upward.
[0041] The piston 53 is formed by sealing a lower end of a
cylindrical member 53b having outer diameter slightly smaller than
the in diameter of the cylinder part 52 by a disc shaped member 53a.
Around the upper and lower sides of the member 53b of the piston
30 53, O-ring grooves are formed, and the piston 53 is inserted into
the housing 50 (cylinder part 52) in a condition where an O-ring
is fitted in each O-ring groove.
[0042] Near the upper end of the piston 53 (member 53b), a
plurality of (in the present embodiment, six number of) cam
13
􀀃
followers 54 are attached at equal angular intervals.
[0043] The shaft part 60 is a cylindrical member that is fixed
to the housing 50 (top cover 51). A cam groove 61 having the shape
shown in FIG. 6 is formed on the outside surface of the shaft part
5 60.
[0044] Namely, the cam groove 61 on the outside surface of the
shaft part 60 has a shape that allows a relative angle of the cam
follower 54 to the shaft part 60 to be changed for 30 degrees in
a certain direction when the cam follower 54 positioned at the lower
10 end of the cam groove 61 reaches the upper end of the cam groove
61 along the cam groove 61. Further, the cam groove 61 has a shape
that allows the relative angle of the cam follower 54 to the shaft
part 60 to be changed for 30 degrees in the same direction when the
cam follower 54 positioned at the upper end of the cam groove 61
15 reaches the lower end of the cam groove 61 along the cam groove 61.
[0045] Moreover, the selector valve 30 is configured in such
a manner that sizes of each part (length in the vertical direction
of the cam groove 61, installation angle of the valve element 40
to the stem 45, etc.) satisfies the following conditions.
20 (1) The upper surface of the valve element 40 becomes a position
lower than the lower end of each raw water outlet 32b when the cam
follower 54 is positioned at the lower end of the cam groove 61(see.
FIG. 4).
(2) States shown in FIGS. 7 to 9, namely, states where the side
25 surface openings of the channels 41a and 41b are respectively
opposed to the raw water outlets 32b of the selector valve body part
30a, are provided when the cam follower 54 is positioned at the upper
end of the cam groove 61.
[0046] Hereinafter, function of the pressure-type filtration
30 device 1 will be discussed. Note that, in the following discussion,
a control device is defined as a device (a kind of computer) to
control the filtered water valve 27, the water discarding valve 28
and the selector valve 30 of the pressure-type filtration device
1. The normal position is a position of the valve element 40 in
14
􀀃
the housing 31 when the cam follower 54 is positioned at the lower
end of the cam groove 61 (see FIG. 4). The backwashing position
is a position of the valve element 40 in the housing 31 when the
cam follower 54 is positioned at the upper end of the cam groove
5 61 (see FIG. 9). The backwashing position of a filtration chamber
12 is defined as the backwashing position, among six backwashing
positions where the orientations (rotary angles in the housing 31)
of the valve element 40 are different, to which the side surface
opening of the washing waste water channel 41b is directed.
10 [0047] In the filtering step of raw water by the pressure-type
filtration device 1, the filtered water valve 27, the water
discarding valve 28 and the selector valve 30 are controlled by the
control device in such a manner that the filtered water valve 27
is opened, the water discarding valve 28 is closed and the selector
15 valve 30 is positioned in the normal position. The state where the
filtered water valve 27 is opened, the water discarding valve 28
is closed and the selector valve 30 is positioned in the normal
position will be denoted hereinafter as the filtering state.
[0048] The upper surface of the valve element 40 positioned
20 in the normal position is lower than the lower end of each raw water
outlet 32b of the housing 31 (FIG. 4). Further, the shape of each
raw water outlet 32b is the same. Accordingly, when the filtering
state is formed, raw water flowing into the selector valve body part
30a through the six raw water inlets 32a from the raw water chamber
25 11 is equally distributed to the six filtration chamber 12 through
the six raw water outlets 32b in the selector valve body part 30a.
[0049] Further, the filtering state is the state where the
filtered water valve 27 is opened and the water discarding valve
28 is closed, and therefore filtered water supplied to the purified
30 chamber 13 from each filtration chamber 12 flows out from the
filtered water outlet 22d through the filtered water pipe 22
(filtered water pipes 22b, 22c and 22a).
[0050] When a predetermined backwashing start condition,
e.g., a backwashing start condition such as "filtration of raw water
15
􀀃
is performed for a prescribed time(e.g., 24 to 48 hours)" or
"filtration resistance rises and reaches the set value" is
satisfied, the control device performs backwashing step of the
following contents.
5 [0051] The control device, to start with, performs a first
control processing to form "a backwashing state where the filtered
water valve 27 is closed, and water discarding valve 28 is closed,
and the valve element 40 is positioned in the backwashing position
for a certain filtration chamber 12". The control performed to the
10 selector valve 30 in the first control processing is control to
rotate the valve element 40, which is positioned in the normal
position, 30 degrees and thereby raise it to the backwashing
position (that is, control to raise the piston 53 positioned at the
lower end to the upper end). The control performed to the selector
15 valve 30 in the first control processing may be control in which
the rotation angle of the valve body 40 is not 30 degrees, so long
as it can move the valve element 40 to the washing position
[0052] When the valve element 40 is positioned in the
backwashing position for a filtration chamber 12 (which will be
20 hereinafter denoted as the backwash target filtration chamber 12),
the side surface opening of each channel 41a, 41b in the valve element
40 is opposed to each raw water outlet 32b of the housing 31 (see
FIG. 9). Further, the raw water channel 41a, the washing waste water
channel 41b communicates between the side and upper surfaces of the
25 valve element 40, between the side and lower surfaces of the valve
element 40, respectively, and each raw water channel 41a has
approximately the same shape.
[0053] Therefore, when the valve element 40 is positioned in
the backwashing position for the backwash target filtration chamber
30 12, the raw water flowing into the selector valve body part 30a from
the raw water chamber 11 is evenly distributed to five filtration
chamber 12 other than the backwash target filtration chamber 12
through five raw water channels 41a of the valve element 40.
[0054] Further, when the valve element 40 is positioned in the
16
􀀃
backwashing position for the backwash target filtration chamber 12,
the raw water introducing port of the backwash target filtration
chamber 12 (the raw water outlet 32b from which raw water is supplied
to the backwash target filtration chamber 12) is communicated with
5 the waste water pipe 24 by the washing waste water channel 41b of
the valve element 40. That is, the backwash target filtration
chamber 12 goes into a state where water can flow from the lower
part to the upper part because the raw water introducing port is
open (raw water is not introduced from the raw water introducing
10 port). Further, when both of the filtered water valve 27 and the
water discarding valve 28 are closed, the filtrated water in the
purified water chamber 13 cannot flow out to the filtered water pipe
22b.
[0055] Therefore, when the above backwashing state, as
15 schematically shown in FIG. 10B, the backwash target filtration
chamber 12 is backwashed with filtered water from five filtration
chamber 12 other than the backwash target filtration chamber 12,
and washing waste water from the backwash target filtration chamber
12 flows out to the outside through the washing waste water channel
20 41b and the waste water pipe 24.
[0056] The control device which finished the first control
processing of the above contents waits until a backwashing time
(e.g., 6 to 7 minutes) passes which is set beforehand as time to
perform backwashing.
25 [0057] When the backwashing time passes, the control device
performs control to the selector valve 30 (drive part 30b), the
control being to lower the piston 53 positioned at the upper end
to the lower end and then raise it to the upper end. When this
control (which will be referred to as backwash target change
30 control) is performed, the valve element 40 is positioned in the
backwashing position for the filtration chamber 12 next to the
filtration chamber 12 that is backwashed, and therefore the control
device waits until the backwashing time passes.
[0058] When the backwashing time passes, the control device
17
􀀃
performs the backwash target change control again, and then waits
until the backwashing time passes.
[0059] The control device repeats the above control processing
until backwashing of every filtration chambers 12 is completed.
5 When backwashing of every filtration chamber 12 is completed, the
control device performs control to the selector valve 30 (drive part
30b), the control being to lower the piston 53 positioned at the
upper end to the lower end and then raise it to the upper end, and
controls the water discarding valve 28 so as to open.
10 [0060] When the above control is performed to the water
discarding valve 28, "a state where the filtered water valve 27 is
closed, the water discarding valve 28 is opened and the valve element
40 is positioned in the normal position" is formed. Therefore, it
follows that filtered water from six filtration chambers 12 flows
15 out from the waste water pipe 24 through the water discarding pipe
23 as schematically shown in FIG. 10C.
[0061] The control device that forms the above state (which
will hereinafter be termed the water discarding state) by
controlling the selector valve 30 and the water discarding valve
20 28 waits until a time (e.g., ten minutes) set beforehand passes.
When that time passes, the control device controls the filtered
water valve 27 and the water discarding valve 28 such that the
filtered water valve 27 is opened and the water discarding valve
28 is closed. Namely, the control device performs control to
25 restore the pressure-type filtration device 1 to the state where
raw water is filtered (state where filtered water from six
filtration chamber is flowed out from the filtered water outlet
22d). Then, the control device having finished the control enters
a state of monitoring whether the backwashing start condition is
30 satisfied.
[0062] As discussed above, the pressure-type filtration
device 1 according to the present embodiment includes six filtration
chambers 12 arranged concentrically and the raw water chamber 11
arranged in the central part of the filtration chambers 12.
18
􀀃
Moreover, in the pressure-type filtration device 1, raw water is
supplied to each filtration chambers 12 from each of the raw water
outlets 32b having the same shape provided in the selector valve
body part 30a (see FIG. 4). Accordingly, in the pressure-type
5 filtration device 1, substantially uniform amount of raw water is
supplied to each filtration chamber 12 in the filtration step.
[0063] Further, the pressure-type filtration device 1
includes the purified water chamber 13 which can act as the filtered
water path that introduces filtered water from the filtration
10 chambers 12 other than the backwash target filtration chamber 12
to the filtered water outlet (the water collection board 15) of the
backwash target filtration chamber 12. Moreover, this purified
water chamber 13 is provided at the central part (just below six
filtration chambers 12, see FIG. 3) of six filtration chambers 12.
15 Therefore, in the pressure-type filtration device 1, a total of
water filtered in the filtration chambers 12 other than the backwash
target filtration chamber 12 is supplied to the backwash target
filtration chamber 12 in the backwashing step.
[0064] Furthermore, the filtration device main body 10 of the
20 pressure-type filtration device 1 has such constitution that the
raw water chamber 11 and a plurality of filtration chambers are
placed in one outer shell 10 with no gaps therebetween.
Accordingly, the pressure-type filtration device 1 can be installed
in a smaller area than the pressure-type filtration device to which
25 other constitution is adopted to equalize filtered water supplied
to each filtration chamber (the pressure-type filtration device 2
which will be discussed later and the like).
[0065] <>
FIG. 11 is a sectional view of the pressure-type filtration
30 device 2 according to a second embodiment of the present invention,
and FIG. 12 is a top plan view of the pressure-type filtration device
2.
[0066] The pressure-type filtration device 2 according to the
present embodiment is an device to which the principle of the self
19
􀀃
backwashing equipment is applied as with the pressure-type
filtration device 1.
[0067] As illustrated in FIG. 11 and FIG. 12, the pressure-type
filtration device 2 includes six filtration chamber 70, a raw water
5 chamber 71, a waste water chamber 72, a purified water chamber 73,
a raw water pipe 80 for supplying raw water to the raw water chamber
71, and so on. Further, the pressure-type filtration device 2 (FIG.
11) has such constitution that the raw water chamber 71, the waste
water chamber 72 and the purified water chamber 73 are lined up to
10 the vertical direction.
[0068] Each filtration chamber 70 of the pressure-type
filtration device 2 is a filtration chamber (filter) having the same
configuration, which includes a water collection board 70c and
filtering material (in FIG. 11, anthracite manganese sand and
15 filtration gravel) arranged on the water collection board 70c. As
shown in FIG. 12, six filtration chambers 70 of the pressure-type
filtration device 2 is arranged concentrically centering on the part
consisting of the raw water chamber 71, the waste water chamber 72
and so on.
20 [0069] As shown in FIG. 11, a raw water introducing port 70a
of each filtration chamber 70 is connected to the raw water chamber
71 and the waste water chamber 72 by a pipe system of the same
constitution including a three-way valve 75. Note that the pipe
system connecting each filtration chamber 70 to the raw water
25 chamber 71 and the waste water chamber 72 may be the pipe system
constituted by using pipes having the same inner diameter or the
pipe system constituted by using pipes having pipes having different
inner diameters so long as it allows a required quantity of filtered
water to be flowed back in the filtration chamber 70.
30 [0070] The filtered water outlet 70b of each filtration chamber
70 is connected to the purified water chamber 73. The pipe of the
approximately same shape (inner diameter, length) is used for
connection between the filtered water outlet 70b of each filtration
chamber 70 and the purified water chamber 73.
20
􀀃
[0071] To the waste water chamber 72, a waste water pipe 83
is attached, which extends from the center art of the lower surface
of the waste water chamber 72 and penetrates the purified water
chamber 73. In the purified water chamber 73, one end of a filtered
5 water pipe 81a is inserted which extends to the lower surface of
the waste water chamber 72 in the form of accommodating the waste
water pipe 83 therein. To the part of the filtered water pipe 81a
higher than the upper surface of the filtering material in each
filtration chamber 70, one end of a filtered water pipe 81b the other
10 end of which functions as a filtered water outlet 81d. At the part
of the filtered water pipe 81b near the filtered water outlet 81d,
a filtered water valve 76 is provided, and the part of the filtered
water pipe 81b upstream from the filtered water valve 76 and the
waste water pipe 83 are connected via a water discarding pipe 82
15 provided with a water discarding valve 77.
[0072] A function of pressure-type filtration device 2 will
be explained.
At the time of the filtration step of raw water by the
pressure-type filtration device 2, the valves 75-77 are controlled
20 by a control device for the pressure-type filtration device 2, and
"a filtering state where the filtered water valve 76 is opened, the
water discarding valve 77 is closed, and each three-way valve 75
communicates the filtration chamber 70 with the raw water chamber
71" is formed.
25 [0073] As already explained, each pipe system connecting the
filtration chamber 70 with the raw water chamber 71 and waste water
chamber 72 has the same constitution. As shown in FIG. 11, a raw
water introducing port 70a of each filtration chamber 70 is
connected to the raw water chamber 71 and the waste water chamber
30 72 by a pipe system having the same constitution including a
three-way valve 75. Note that the pipe system connecting each
filtration chamber 70 to the raw water chamber 71 and the waste water
chamber 72 may be the pipe system constituted by using pipes having
the same inner diameter or the pipe system constituted by using pipes
21
􀀃
having pipes having different inner diameters so long as it allows
a required quantity of filtered water to be flowed back in the
filtration chamber 70. Therefore, when each three-way valve 75
connects the filtration chamber 70 with the raw water chamber 71,
5 raw water supplied from the outside through raw water pipe 80 is
equally distributed to the six filtration chamber 70 through the
raw water chamber 71 as schematically shown in FIG. 13. The
filtration state is a state where each filtration chamber 70 is
communicated with the raw water chamber 71 by each three-way valve
10 75, the filtered water valve 76 is opened and water discarding valve
77 is closed. Accordingly, it flows that, when the filtering state
is formed, filtered water from each filtration chamber 70, to which
the same quantity of raw water is supplied, flows out from the
filtered water outlet 81d of the filtered water pipe 81b through
15 the purified water chamber 73 and filtered water pipe 81a.
[0074] Moreover, when the predetermined backwashing condition
is satisfied, the control device performs control processing for
backwashing of the following contents.
[0075] The control device having started the control
20 processing for backwashing, to begin with, performs a first control
processing to form "a backwashing state where the filtered water
valve 76 and the water discarding valve 77 are closed, one three-way
valve 75 communicates the filtration chamber 70 with the waste water
chamber 72, and each of the other three-way valves 75 communicates
25 the filtration chamber 70 with the raw water chamber 71."
[0076] When the above backwashing state is formed, the
filtration chamber 70 (denoted hereinafter as the backwash target
filtration chamber 70) that is communicated with the waste water
chamber 72 through the three-way valve 75 goes into a state where
30 water can flow from the lower part to the upper part. Also, it comes
to raw water in the raw water chamber 71 to be equally distributed
to only five filtration chambers 70 other than the backwash target
filtration chamber 70. Therefore, it follows that, when the above
backwashing state is formed, the backwash target filtration chamber
22
􀀃
70 (the left side filtration chamber 70 in FIG. 11) is backwashed
with filtered water from five filtration chamber 70 other than the
backwash target filtration chamber 70, and washing waste water from
the backwash target filtration chamber 70 flows out to the outside
5 through the waste water chamber 72 and the waste water pipe 83 as
schematically shown in FIG. 14.
[0077] The control device having finished the first control
processing waits until a backwashing time set beforehand as an
execution time of backwashing passes. Then, when the backwashing
10 time passes, the control device performs the first control
processing again in the form that the backwashing target filtration
chamber 70 is changed to another filtration chamber 70 to which
backwashing is not carried out, and thereafter waits until the
backwashing time passes.
15 [0078] The control device repeats the above processing until
backwashings of all filtration chamber 70 are completed. When
backwashings of all filtration chamber 70 are completed, the control
device forms "a water discarding state where the filtered water
valve 76 is closed, the water discarding valve 77 is opened, and
20 each three-way valve 75 communicates the filtration chamber 70 with
the raw water chamber 71" by controlling valves 75-77. When the
backwashing state is formed, it follows that filtered water from
six filtering chamber 70 flows out from the waste water pipe 83
through the water discarding pipe 82 as shown in FIG. 15.
25 [0079] Thereafter, the control device waits until a preset time
(e.g., ten minutes) passes, and controls the filtered water valve
76 and the water discarding valve 77 such that the filtered water
valve 76 is opened and the water discarding valve 77 is closed when
the preset time passes. That is, the control device performs
30 control to restore the pressure-type filtration device 2 to the
state where raw water is filtered (state where filtered water from
six filtration chamber 70 is flowed out from the filtered water
outlet 81a). Then, the control device having finished the control
enters a state of monitoring whether the backwashing start condition
23
􀀃
is satisfied. The control device having finished the control
terminates the backwashing control processing and enters into the
status of monitoring whether the backwashing start condition is
satisfied.
5 [0080] As discussed above, the pressure-type filtration
device 2 according to the present embodiment includes six filtration
chambers 70 arranged concentrically and the raw water chamber 71
arranged in the central part of the filtration chambers 70.
Moreover, in the pressure-type filtration device 2, raw water in
10 the water chamber 71 is supplied to the raw water introducing port
70a of each filtration chambers 70 by the pipe system having the
same constitution. Accordingly, in the pressure-type filtration
device 2, substantially uniform amount of raw water is supplied to
each filtration chamber 70 in the filtration step.
15 [0081] Further, the pressure-type filtration device 2
includes the purified water chamber 73 which can act as the filtered
water path that introduces filtered water from the filtration
chambers 70 other than the backwash target filtration chamber 70
to the filtered water outlet 70b of the backwash target filtration
20 chamber 70. This purified water chamber 73 is provided at the
central part of six filtration chambers 70, and the filtered water
outlet 70b of each backwash target filtration chamber 70 is
connected to the purified water chamber 73 by the pipe having the
same shape. Therefore, it follows that, in the backwashing step
25 of the pressure-type filtration device 1, substantially uniform
amount of raw water is supplied to each filtration chamber 70.
[0082] <>
The reason why the pressure-type filtration device of each
embodiment is configured as an device where the number of the
30 filtration chambers is six and one filtration chamber is backwashed
in the backwashing step, is that it is assumed that the flow velocity
required for backwashing (hereinafter, backwashing step flow
velocity) is 1,000 m/day and the filtration speed in the backwashing
step (hereinafter, backwashing step filtration speed) is 200 m/day.
24
􀀃
That is, when the backwashing flow velocity and the backwashing step
filtration speed are the above values, the flow velocity (filtered
water quantity) required to backwash one filtration chamber 70 can
be covered by filtered water from five filtration chambers 70. The
5 pressure-type filtration device of each embodiment is therefore
configured as an device where the number of the filtration chambers
is six and one filtration chamber is backwashed in the backwashing
step. However, the number of filtration chambers may not necessarily
be six, and the number of filtration chambers that are backwashed
10 in the backwashing step may not necessarily be one.
[0083] Specifically, the value of "the backwashing flow
velocity / backwashing step filtration speed" varies according to
the application (filtering material in each filtration chamber) of
the pressure-type filtration device. Therefore, for example, when
15 the backwashing flow velocity is 1,000 m/day and the backwashing
step filtration speed is 500 m/day, the number of the filtration
chambers that act as raw water supply sources and the number of the
filtration chambers that are backwashed in the backwashing step may
be 2N (in N is natural number) and N, respectively. Further, when
20 the value of "the backwashing flow velocity / backwashing step
filtration speed" is approximately three, the number of the
filtration chambers that act as raw water supply sources and the
number of the filtration chambers that are backwashed in the
backwashing step may be 3N and N, respectively.
25 [0084] Note that the pressure-type filtration device 2
according to the second embodiment can be operated in such a manner
that two filtration chamber 70 are backwashed in the backwashing
step by altering control to six three-way valves 75 without changing
the constitution. Further, the pressure-type filtration device 1
30 according to the first embodiment can be modified to the device of
which two filtration chamber 70 are backwashed in the backwashing
step by changing the valve element 40 to the valve element 40' shown
in FIGS. 16A and 16B, namely, the valve element 40' provided with
four raw water channel 41a and two washing waste water channel 41b
25
􀀃
therein.
[0085] As described above, in the pressure-type filtration
device 1, the selector valve 30 where the diameter of the raw water
outlet 32b is approximately 2.5 times larger than the diameter of
5 the raw water inlet 32a and the inner diameter of the washing waste
water channel 41b of the valve element 40 is approximately 2.5 times
larger than the inner diameter of the raw water channel 41a, is used.
Purpose of using the selector valve 30 having such constitution is
to prevent that filtered waste quantity that flows backward in the
10 backwash target filtration chamber is limited by channel resistance
of the washing waste water channels 41b and the raw water outlets
32b (see FIG. 9). Further, in order to cause the required amount
of filtered water to flow backward in the filtration chamber 12,
the cross-section ratio of the washing waste water 41b and the raw
15 water channel 41a may be larger/smaller than the above-mentioned
value.
[0086] The pressure-type filtration device 2 according to the
second embodiment may be modified into the pressure-type filtration
device 2' having constitution shown in FIG. 17. That is, the
20 pressure-type filtration device 2 may be modified into the
pressure-type filtration device 2' in which two two-way valves 75a
and 75b are used instead of each three-way valve 75.
[0087] The pressure-type filtration device 1, 2 may be modified
into such devices where the waste water pipe 24 and the filtered
25 water pipe 22b, the waste water pipe 83 and the filtered water pipe
81a does not constitutes a double pipe.
[0088] The pressure-type filtration device 2 may be modified
into such devices in which the selector valve is used instead of
six three-way valves 75 and the waste water chamber 72. Note that
30 modification of the pressure-type filtration device 2 into such
devices can be made, for example, by adopting configuration where
raw water in the raw water chamber 71 flows into the selector valve
body part 30a through each raw water inlet 32a, each raw water outlet
32b of the selector valve body part 30a is connected to the raw water
26
􀀃
inlet 70a of each filtration chamber 70 by pipe, and the opening
32c is connected to waste water pipe 83 by pipe, as shown in FIG,
18.
[0089]
5 The plurality of filtration chambers (12, 70) in the pressure-type
filtration device 1, 2 are not necessarily arranged in a perfect
circle so long as they are arranged concentrically. Therefore, the
filtration device main body 10 (see FIG. 2) of the pressure-type
filtration device 1 may be modified into a unit comprising outer
10 shell 10a having noncylindrical shape. The pressure-type
filtration device 2 may be modified into such devices where
distances between some filtration chambers 70 and the raw water
chamber 71 are longer/shorter than distances between the other
filtration chambers 70 and the raw water chamber 71. Further, the
15 plurality of filtration chamber in the pressure-type filtration
device 1, 2 are not necessarily arranged with a constant angular
space. Therefore, the pressure-type filtration device 1 may be
modified into such devices having a semicircle shape or a fan shape
in a top view. Also, the pressure-type filtration device 2 may be
20 modified into such devices where a plurality of filtration chamber
70 is arranged along an arc such as a semicircle.
[DESCRIPTION OF THE REFERENCE NUMERALS]
[0090]
25 1, 2 pressure-type filtration device
10 filtration device main body
10a outer shell
11, 71 raw water chamber
12a filtering material
30 12, 70 filtration chamber
13, 73 purified water chamber
15 water collection board (filtered water outlet)
18 maintenance port
20, 80 raw water pipe
27
􀀃
22a - 22c, 81a, 81b filtered water pipe
22d filtered water outlet
23, 82 water discarding pipe
24, 83 waste water pipe
5 27, 76 filtered water valve
28, 77 water discarding valve
30 selector valve
30a selector valve body part
30b drive part
10 31, 50 housing
32a raw water inlet
32b raw water outlet
32c opening
38a, 51a pressurized air introducing port
15 38 isolation plate
40 valve element
41a raw water channel
41b washing waste water channel
45 stem
20 52 cylinder part
53 piston
54 cam follower
60 shaft part
61 cam groove
25 70a raw water introducing port
70b filtered water outlet
70c water collection board
72 waste water chamber
75 three-way valve
30 75a, 75b two-way valve

I/We Claim:
1. A pressure-type filtration device comprising:
a plurality of filtration chambers each of which has filtering
5 material therein and which are arranged concentrically;
a raw water distribution part which is arranged at a center
part of the plurality of filtration chambers in a plan view and to
which raw water to be filtered is supplied from the outside;
a flow channel system which connects raw water introducing
10 ports of the plurality of filtration chambers and the raw water
distribution part and is capable of attaining a first state and a
second state, the first state being a state in which the raw water
in the raw water distribution part is distributed to the raw water
introducing ports of the plurality of filtration chambers, and the
15 second state being a state in which a raw water introducing port
of a backwash target filtration chamber and a waste water pipe are
connected and raw water in the raw water distribution part is
distributed to the raw water introducing ports of the filtration
chambers other than the backwash target filtration chamber; and
20 a purified water chamber into which filtered water from the
filtered water outlets of the plurality of filtration chambers
flows, and which act as a filtered water path which guides the
filtered water from the plurality of filtration chambers other than
the backwash target filtration chamber to the filtered water outlet
25 of the backwash target filtration chamber.
2. The pressure-type filtration device according claim 1,
wherein the plurality of filtration chambers, the raw water
distribution part and the purified water chamber are provided in
30 a filtration body, and
the plurality of filtration chambers have shapes formed by
equally dividing an inner part of the filtration body excluding the
raw water distribution part and the purified water chamber along
radial directions from the center of the filtration body.
29
􀀃
3. The pressure-type filtration device according claim 1,
wherein the flow channel system includes discrete channel systems
which are provided to each filtration chamber and each of which has
5 one or more valve devices to alternatively connect the raw water
introducing port of the filtration chamber to the raw water
distribution part and the waste water pipe.
4. The pressure-type filtration device according claim 2,
10 wherein the filtration body is circular in cross-section view.