JPH0255088B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting and stopping a backwash siphon tube in a gravity filtration device.

Conventionally, when starting each siphon in a gravity-type filtration device, a vacuum pump or ejector was connected to the top of the siphon tube, and the vacuum pump or ejector reduced the air pressure in the siphon tube to start the siphon. A drawback is that an expensive vacuum pump or pressure water pump for the ejector must be provided as a power source.

The present invention compensates for these conventional drawbacks and makes it possible to reliably start and stop a backwashing siphon pipe without the need for a special power source, with low production costs and operation management costs, and with simple operation. purpose.

That is, the present invention includes a plurality of filter basins 3 which are partitioned by a partition wall 14 into a floor 6 and a backwash wastewater inflow chamber 13, and which are installed adjacent to and separated from the backwash wastewater inflow chamber 13, so that the backwash water of the floor 6 is separated from the backwash wastewater inflow chamber 13. A common backwash drainage retention conduit 16 that maintains the water level below the water level at which the backwash water overflows and communicates with the bottom of the floor 6 and maintains the water level above the water level at which the backwash water in the floor 6 overflows. The common overwater drain 9, each backwash wastewater inflow chamber 13, and the common backwash wastewater retention drain 16 are connected to each other by having a bent portion above the water level of the overwater basin 3, and both ends thereof are It consists of at least a plurality of backwashing siphon tubes 5 consisting of sealed inverted U-shaped tubes,
In a gravity-type filtration device in which the water in the backwash drainage inlet chamber 13 is discharged through a backwash siphon pipe 5 and the excess water is caused to flow back to the floor 6 by the water head held by the overflow conduit 9, backwashing is performed. Distance H ₁ between the water surface of the backwashing wastewater inflow chamber 13 and the top of the backwashing siphon pipe 5 when trying to start the backwashing siphon pipe 5
, the low level water level in the water tank 19 and the backwash drainage retention conduit 16 of the suction and drainage pipe 23 attached to the water tank 19, which will be described later.
The distance H ₂ from the water seal water level in the water tank 19 has a relationship of H ₁ <H ₂ , and the distance H ₅ between the high level water level in the water tank 19 and the water seal water level in the suction/discharge pipe 23 and the water seal water level in the backwash siphon pipe The airtight water tank 19 is installed so that the distance H ₄ between the upper part of the backwashing siphon pipe 5 and the water surface of the backwashing water retention conduit 16 satisfies the relationship H ₅ <H ₄ . The upper part and the water tank 19 are connected by a common communication pipe 20, and the communication pipe 20
common automatic valves V ₂ in order from the one closest to water tank 19,
A common siphon stop automatic release valve V ₃ and an automatic valve V ₁ for each backwash siphon pipe are provided, and the water tank 19 is further provided with a water surface detection meter 25 for detecting a high level water level in the water tank 19. The automatic valve V ₂ is linked to a total of 25, and the water tank 1
9 is provided with a suction/drainage pipe 23 whose lower end is water-sealed and whose upper end penetrates the water tank 19 and opens within the water tank 19, and has an inner diameter larger than that of the suction/drainage pipe 23;
An outer cylindrical pipe 29 whose upper part is sealed and has a water flow port 30 below the opening of the suction/drainage pipe 23 in the water tank 19 is fixed in the water tank 19 so as to cover the suction/drainage pipe 23 in the water tank 19. An air discharge valve V ₅ consisting of an automatic valve or a manual valve is installed at the upper part of the outer cylinder pipe 29.
A water tank 19 is connected with an exhaust pipe 28 having an inlet valve V6, and a supply pipe 21 is provided in the water tank 19 with an inlet valve _V6 consisting of an automatic valve or a manual valve. When discharging from the water level to the low level water level from the suction/drainage pipe 23,
By suctioning the air present inside the backwashing siphon pipe 5 and the communication pipe 20, the water in the backwashing wastewater inflow chamber 13 is sucked up, and the backwashing siphon pipe 5
When starting and stopping one of the plurality of backwashing siphon pipes 5, when starting the first backwashing siphon pipe 5, the automatic valve V ₂ and the siphon stop automatic opening are used. The valve V ₃ and the inflow valve V ₆ are opened to fill water into the water tank 19, and when the water level reaches the above-mentioned high level, the automatic valve V ₂ is closed, and the inflow valve V ₆ and the siphon stop automatic release valve V ₃ are opened. , then open the automatic valves V ₁ and V ₂ of the backwashing siphon pipe 5 to be activated, close the automatic valve V ₁ of the other backwashing siphon pipe 5, and open the air discharge valve V ₅ The backwashing siphon pipe 5 is started by opening the water tank 19 to discharge the water in the water tank 19 from the suction/discharge pipe 23 according to the water head difference, and then immediately closing the air discharge valve V ₅ . The automatic valves V ₁ and V ₂ of the backwashing siphon pipe 5 are opened, water is sucked up from the suction and drainage pipe 23 by the negative pressure generated at the upper part of the backwashing siphon pipe 5, and the water level reaches the high level water level. Close automatic valve V ₂ when the temperature reaches
The water in the water tank 19 is used as starting water for the next backwashing siphon pipe 5, and the automatic valve _V1 of the backwashing siphon pipe 5 which is started is used.
When opening the siphon stop automatic release valve V ₃ to stop the backwashing siphon pipe 5, and when starting the backwashing siphon pipe 5 next time,
Close the siphon stop automatic release valve V ₃ , open the automatic valves V ₁ and V ₂ of the backwash siphon pipe 5 to be activated, and close the automatic valve V ₁ of the other backwash siphon pipe 5. , the backwashing siphon pipe 5 is activated by discharging the water in the water tank 19 sucked up from the suction and drainage pipe 23 according to the water head difference, and the automatic valve of the backwashing siphon pipe 5 is activated even after activation.
V ₁ and automatic valve V ₂ are opened, water is sucked up from the suction and drainage pipe 23 by the negative pressure generated in the upper part of the backwashing siphon pipe 5, and when the water level reaches the above-mentioned high level, automatic valve V ₂ is opened. The water tank 19 is closed and the water is retained in the water tank 19, and the water in the water tank 19 is used as starting water for the backwashing siphon pipe 5 from the next time onwards. The present invention relates to a method for starting and stopping a backwashing siphon tube of a gravity-type filtration device, which is characterized by sequentially repeating stopping and stopping of the washing siphon tube 5.

The present invention will be explained in detail below with reference to the drawings.

Each of the drawings is a longitudinal cross-sectional view showing an example of an embodiment of a filtration device using the starting and stopping device for a backwashing siphon pipe of the present invention, and as shown in FIG. 1, a plurality of filter ponds 3 are provided in a row in the vertical direction, and a raw water inflow conduit 2 common to each of the filter ponds 3 is provided above the filter ponds 3. In addition, a raw water distribution chamber 4 is provided on the side of the raw water inflow conduit 2 corresponding to each filter pond 3, and a raw water inflow chamber 15 is provided outside the raw water distribution chamber 4 via a water seal weir 27. Each raw water distribution chamber 4 and raw water inflow conduit 2 are read directly through a plurality of water flow siphon pipes 22 (for convenience, only one water flow siphon pipe 22 is shown). Further, each filter basin 3 is partitioned into two chambers by a partition wall 14, one chamber is used as a backwash wastewater inflow chamber 13, and each chamber 13 and each raw water inflow chamber 15 are communicated with each other through a plurality of raw water pipes 24. Further, a support bed 7 is provided below the other chamber of each of the overpass ponds 3, and a floor 6 is formed above the support bed 7, and above the bed 6 and opposite to the height of the upper end of the partition wall 14. A plurality of wash drainage gutters 12 are provided, and one end of the backwash drainage gutters 12 on the partition wall 14 side is opened. In addition, an overwater collection chamber 8 is provided below the support floor 7, and the chamber 8 is connected to a common overwater conduit 9.
The overflow water flowing out from each overwater basin 3 is made to flow through each overflow water collecting chamber 8 and into a common overwater conduit 9. Further, the overwater drain 9 is communicated with the overwater outflow drain 10 via an overflow weir 11, and the overflow weir 11 is provided so as to be higher than the upper end of the backwash drainage gutter 12, so that the water level of the overwater drain 9 is is maintained approximately constant at the height of the overflow weir 11. In addition, a water surface detector 26 is attached to each pond 3.

In addition, a common backwash wastewater retention conduit 16 is arranged adjacent to and separated from each backwash wastewater inflow chamber 13, and the backwash wastewater retention conduit 16 and the backwash wastewater inflow chamber 13 of each filter basin 3 are connected. Each filter basin 3 is communicated with a plurality of backwashing siphon pipes 5 which are inverted U-shaped pipes having a bent portion above the water level and having both ends sealed with water (for convenience, the backwashing siphon pipes 5 (Only one unit is shown.) Further, a backwash wastewater outflow culvert 18 is provided further outside the backwash wastewater retention culvert 16, and a water seal weir 17 having a height lower than the partition wall 14 is provided between the backwash wastewater retention culvert 16 and the backwash wastewater outflow culvert 18. The water level of the backwash wastewater retention conduit 16 is kept constant at the height of the water seal weir 17.

In addition, the sealed water tank 19 is backwashed to the waste water retention conduit 16.
Distance H ₁ between the water surface of the backwash wastewater inflow chamber 13 and the upper part of the backwash siphon pipe 5 when the backwash siphon pipe 5 is to be activated,
As will be described later, the distance H ₂ between the low level water level D in the water tank 19 and the water surface of the backwash wastewater retention conduit 16 has a relationship of H ₁ < H ₂ , and the high level water level A in the water tank 19 and the water suction pipe (described later) The distance H ₅ from the water seal water level of 23,
The upper part of the backwashing siphon pipe 5 and the backwash wastewater retention conduit 1
6 so that the distance H ₄ from the water surface satisfies the relationship H ₅ <H ₄ . Note that the capacity of the water tank 19 will be described later. Further, in this embodiment, water from the raw water inflow conduit 2 is used as the water required for starting the siphon pipe for the first time, but the present invention is not limited to this, and other water may be used. In addition, a common communication pipe 2 is connected to the upper part of the water tank 19.
0, and attach a common automatic valve V ₂ and a common siphon stop automatic release valve V ₃ to the communication pipe 20 from the side closest to the water tank 19, and after installing the siphon stop automatic release valve V ₃ . The communication pipe 20 is branched and connected to the upper part of each backwashing siphon pipe 5. In addition, the siphon stop automatic release valve V ₃
An automatic valve V ₁ is provided for each backwashing siphon pipe 5 in each communication pipe 20 between the backwashing siphon pipe 5 and the backwashing siphon pipe 5.
In addition, the said siphon stop automatic release valve V ₃ and automatic valve
The communication pipe 20 between V ₁ is further branched and an automatic valve is installed.
It may be connected to the upper part of each water flow siphon pipe 22 via V ₄ . Further, below the water tank 19, there is provided a water-sealed suction/drainage pipe 23 with its lower end opened below the water surface of the backwash wastewater retention conduit 16. Furthermore, the upper end of the suction/drainage pipe 23 is passed through the water tank 19 and opened at the lower part of the water tank 19, and water flows downward from the opening of the suction/drainage pipe 23 in the water tank 19 as shown in FIG. An outer cylindrical pipe 29 with a sealed upper part having a mouth 30 is fixed in the water tank 19 so as to cover the suction/drainage pipe 23 in the water tank 19, and an air discharge valve consisting of an automatic valve or a manual valve is installed at the upper part of the outer cylindrical pipe 29. Connect the exhaust pipe 28 with V ₅ .

In addition, the water tank 19 and the raw water inflow conduit 2 are communicated via the supply pipe 21 having an inflow valve V ₆ consisting of an automatic valve or a manual valve. Needless to say, when water other than the raw water is supplied, the other end of the supply pipe 21 is connected to the supply source. Note that when the inflow valve V ₆ is opened and raw water is supplied from the supply pipe 21 to the water tank 19, the water level in the water tank 19 rises, and the raw water passes through the water flow port 30 of the outer cylindrical pipe 29 and gradually flows through the water channel 31. However, almost at the same time as the water level in water tank 19 reaches high level A, waterway 3
The height of the suction/drainage pipe 23 in the water tank 19 is adjusted so that the water surface of the water tank 19 reaches the upper end of the suction/drainage pipe 23. In addition, a water surface detector 25 for detecting the high level water level A is provided in the water tank 19, and the water surface detector 25 and the automatic valve _V2 are linked, and as will be described later, the backwashing siphon pipe 5
When the water surface of the water tank 19 reaches the high water level A by sucking up water from the suction and drainage pipe 23 due to the negative pressure generated at the upper part of the water tank 19, the automatic valve _V2 linked to the water level detector 25 closes and water is drawn up from the suction and drainage pipe 23. Configure the system so that water wicking is stopped. Further, the diameter of the suction/drainage pipe 23 is set to such a thickness that the water in the water tank 19 can be rapidly discharged, and the water in the backwash drainage retention conduit 16 can be sucked up into the water tank 19 in a short time.

Further, the low level water level D of the water tank 19 mentioned above is lower than the high level water level A, and the water level D is lower than the high level water level A.
The water tank 19 has a capacity sufficient to suck and depressurize the air present inside the backwashing siphon pipe 5 and the communication pipe 20.
When the water inside is discharged through the suction/discharge pipe 23 with a water head difference, the backwashing siphon pipe 5 is configured to start while the water level reaches from A to D.

When carrying out filtration in such a filtration device 1, first the water flow siphon pipe ₂₂ is activated, but as shown in FIG. siphon tube 2
2, the water flow siphon pipe 22 can be started by using the water tank 19 used in the present invention. That is, the air discharge valve V ₅ is closed, the automatic valve V ₂ and the siphon stop automatic release valve V ₃ are opened to open the water tank 19 to the atmosphere, and the inflow valve V ₆ of the supply pipe 21 is opened to allow raw water to flow into the water tank 19. For example, raw water is supplied from the drain 2 as make-up water. When the water level of the water tank 19 rises to the high water level A, the automatic valve V ₂ is automatically closed, but if the inflow valve V ₆ is a manual valve, it is closed artificially to stop the supply of raw water. Also, when the supply of raw water is stopped, close the siphon stop automatic release valve _V3 . Furthermore, when water is supplied to the water tank 19 in this way, as the water rises in the water channel 31, the air in the water channel 31 is compressed, as shown in FIG. becomes pressurized.

Next, when the automatic valves V ₄ and V ₂ of the water flow siphon pipe 22 are opened and the air discharge valve V ₅ is opened, the pressurized air in the upper part of the outer cylinder pipe 29 flows out through the exhaust pipe 28 and exits. The air pressure in the upper part of the cylindrical pipe 29 decreases, and the water in the water tank 19 flows through the water flow port 30 of the outer cylindrical pipe 29.
The water is rapidly discharged from the suction and drainage pipe 23 via the waterway 31, and the water level in the water tank 19 is lowered. As the water level decreases, the air in the water siphon pipe 22 is sucked into the water tank 19 through the communication pipe 20, and the air pressure in the water siphon pipe 22 is sealed by the raw water inflow conduit 2 and the raw water distribution chamber 4. decreases rapidly, the water level in the water passing siphon pipe 22 rises, and the siphon is activated. In addition, as soon as water starts to be discharged from the suction/discharge pipe 23, the air discharge valve _V5 is closed. If the air exhaust valve V ₅ is left open, it will not be possible to apply suction force to the communication pipe 20, so it is important to close the air exhaust valve V ₅ as soon as water begins to discharge from the suction/discharge pipe 23. It is. However, this operation is performed only for the first activation of the siphon tube, and will not be necessary from the next time onwards.

In this way, the raw water in the raw water inflow conduit 2 flows through the water flow siphon pipe 22 into the raw water distribution chamber 4, then into the raw water inflow chamber 15, and further through the raw water pipe 24 into the over pond 3.
The excess water flows into the backwash wastewater inlet chamber 13, passes over the partition wall 14 and passes through the floor 6 in a downward flow, and the excess water flows out through the excess water collection chamber 8, the excess water conduit 9 and the excess water outflow conduit 10. In this way, the water passage siphon pipe 22
Compared to the backwashing siphon pipe 5, the air capacity inside the siphon pipe is small, for example, about 1/12, and when trying to start the water flow siphon pipe 22, the water surface on the inflow side and the water flow siphon pipe The distance H ₃ from the upper part of the water passage 22 is much smaller than H ₁ in a normal gravity-type filtration device, and there is a relationship of H ₃ ≪ H ₂ . If it is branched and communicated with the water tank to be used, the water in the water tank 19 is rapidly drained by the above-mentioned operation,
It can be started easily.

When the water flow siphon pipe 22 starts, the water tank 1
Discharge of raw water from the suction/discharge pipe 23 of 9 is stopped, and the water level in the water tank 19 becomes constant. Then close the automatic valve V ₄ , open the siphon stop automatic release valve V ₃ ,
The water in the water tank 19 is discharged from the suction and drainage pipe 23.
When the water level in the water tank 19 drops to the water flow port 30, water discharge from the suction/drainage pipe 23 stops, air flows into the water channel 31, and the water level in the water channel 31 decreases. Thereafter, the inflow valve V ₆ is opened, raw water is stored in the water tank 19 up to the high water level A as described above, and the automatic valve V ₂ is closed, and the inflow valve V ₆ and the siphon stop automatic release valve V ₃ are closed. It is on standby for the first activation of the backwashing siphon tube 5.

Note that when water is supplied to the water tank 19 as described above, the air discharge valve V ₅ is closed, so the water level in the water channel 31 rises again, and the air in the upper part of the outer tube 29 and in the suction/discharge pipe 23 is in a pressurized state. becomes. If the above-mentioned washing is continued, the floor 6 will become clogged, so backwashing is performed. In other words, at the beginning of the overflow period, the water level in the overflow pond 3 is almost the same as the water level in the overflow channel 9, but as the floor 6 becomes clogged, the water level in the overflow pond 3 gradually rises until the water level reaches the water level. It reaches B of the detector 26. Automatic valve when reached like this
V ₄ and the siphon stop automatic release valve V ₃ are opened to introduce air into the water flow siphon pipe 22 to turn off the siphon and interrupt the flow of raw water into the filtration pond 3.

Further, when the water sampling time set in advance by a timer (not shown) ends, the automatic valve V ₄ and the siphon stop automatic release valve V ₄ may be opened to stop the water flow siphon pipe 22. When the inflow of raw water is interrupted, the water in the over pond 3 passes through the floor 6 and flows out from the over water culvert 9, and the water level drops from B to C, which is slightly above the water level in the over water culvert 9.
Draining of water is completed.

A water surface detector (not shown) is used to detect the end of water draining.
may be provided to detect that the water level has fallen to C, or the time for the water level to fall to C may be set in advance and detected using a timer (not shown).

After doing this, the first backwashing siphon pipe 5 is started, but in this case, the automatic valve V ₄ and the siphon stop automatic release valve V ₃ are closed, and the automatic backwashing siphon pipe 5 to be started is closed. Open valve V ₁ and automatic valve V ₂ and close automatic valve V ₁ of the other backwash siphon pipe 5, then open the air discharge valve.
Open _V5 . As a result of this operation, the pressurized air in the outer tube 29 is discharged from the exhaust pipe 28, the air pressure in the upper part of the outer tube 29 decreases, and the water in the water tank 19 flows through the water flow port 30 of the outer tube 29 and the water channel 31. Suction and drainage pipe 2
3. Excretes more rapidly. As the water level in the water tank 19 decreases, the air in the backwash siphon pipe 5 is sucked into the water tank 19 through the communication pipe 20 and is sealed by the backwash wastewater inflow chamber 13 and the backwash wastewater retention conduit 16. The air pressure in the backwashing siphon pipe 5 drops rapidly, the water level inside the backwashing siphon pipe 5 rises, and the siphon is activated. Incidentally, when water starts to be discharged from the suction/drainage pipe 23 of the water tank 19, the air discharge valve _V5 is immediately closed in the same way as when the water flow siphon pipe 22 is started. In this way, the water in the filter basin 3 is discharged from the backwash wastewater inflow chamber 13 through the backwash siphon pipe 5, the backwash wastewater retention culvert 16, and the backwash wastewater outflow culvert 18, and the water level in the backwash wastewater inflow chamber 13 is reversed. It falls below the washing drainage gutter 12. Also, during this time, filtration is being carried out in other overwater basins, and the water level in overwater culvert 9 is kept constant at the height of overflow weir 11. Due to the water head difference with the edge, excess water in the overwater drain 9 flows back from the overwater collection chamber 8 to backwash the floor 6, and backwash wastewater flows into the backwash wastewater inflow chamber 13 from the backwash drainage gutter 12. do. In addition, the backwash wastewater flowing into the backwash wastewater inflow chamber 13 passes through the backwash siphon pipe 5 and is discharged from the backwash wastewater retention conduit 16 and the backwash wastewater outflow conduit 18 as described above, Since the water level is maintained below the backwash drainage gutter 12 and above the water level of the backwash drainage retention conduit 16, backwashing of the floor 6 is continuously performed.

On the other hand, when the backwashing siphon pipe 5 is activated, the discharge of water from the suction and drainage pipe 23 of the water tank 19 is stopped, and the water surface in the water tank 19 becomes a low water level D. If automatic valve V ₁ and automatic valve V ₂ are left open after that, a negative pressure of, for example, 4 to 5 m H ₂ O is generated at the upper part of the backwash siphon pipe 5 due to activation of the backwash siphon pipe 5. Therefore, the air in the water tank 19 is transferred to the communication pipe 2.
0 and can be sucked into the backwashing siphon tube 5 in the opposite direction. In addition, as the air is sucked, the backwash wastewater in the backwash wastewater retention conduit 16 is sucked up into the water tank 19 through the suction and drainage pipe 23, and the water level in the water tank 19 rises, but reaches the high level A. Automatic valve V ₂ closes automatically at point.

While the siphon pipe 5 for backwashing is activated for the first time in this way, the negative pressure generated at the upper part of the siphon pipe 5 for backwashing is used to suck up the backwash wastewater from the backwash wastewater retention conduit 16 into the water tank 19. Therefore, it is only necessary to supply make-up water such as raw water to the water tank 19 only when starting the siphon pipe 22 for water flow and the siphon pipe 5 for backwashing for the first time, and each siphon pipe for each siphon from the next time There is no need to separately secure the charging water required when starting the pipe, and there is no need to increase the amount of water discharged from the backwash drainage retention conduit ₁₆ . Valve V ₆ only needs to be activated for the first time, and after that it is basically automatic valve V ₁ ,
The backwashing siphon pipe 5 can be started and stopped only by operating the automatic valve V ₂ and the siphon stop automatic release valve V ₃ .

Next, after backwashing has been performed for a predetermined period of time, the backwashing siphon pipe 5 is stopped, but before that, the water flow siphon pipe 22 may be activated to start water flow. In other words, in a normal gravity filtration device, the capacity of the siphon tube for water flow is much smaller than that for backwashing, and the capacity of the siphon tube for water flow is _much smaller than that for backwashing.
is much smaller than _H1 , the automatic valve _V4 of the water flow siphon pipe 22 is opened, and the communication pipe 2 with the residual negative pressure generated by the activation of the backwashing siphon pipe 5 is
By simply sucking the air in the water-flowing siphon tube 22, the water surface of the water-flowing siphon tube 22 can be raised to easily start the siphon, and water can be started. In addition, when starting the water flow siphon pipe 22, the communication pipe 20 is, for example,
It has a residual negative pressure of 1.5 to 3m H ₂ O, and such negative pressure is enough to start, but if the automatic valve V ₁ is left open, a Since negative pressure is also added, the water flow siphon tube 22 can be activated more easily.

After starting flushing in this way, immediately close the automatic valve V ₄ of the water flow siphon pipe 22, then open the siphon stop automatic release valve V ₃ to release air into the activated backwash siphon pipe 5. will be introduced to stop the discharge of backwash wastewater.

In addition, after performing the filtration for a predetermined time, backwashing is performed again, but first, as described above, open the automatic valve V ₄ of the siphon pipe 22 for water flow, and introduce air into the siphon pipe 22 for water flow. Turn off the siphon and interrupt the flow of raw water. After that, the backwashing siphon pipe 5 is started, but since the inside of the water tank 19, the outer cylindrical pipe 29, and the suction/drainage pipe 23 are full of water, there is no need to open the air discharge valve _V5 from next time onwards.
Just by closing the siphon stop automatic release valve V ₃ and opening the automatic valves V ₁ and V ₂ of the backwashing siphon pipe 5 to be activated, the water in the water tank 19 is rapidly discharged from the suction and drainage pipe 23. As mentioned above, the backwash siphon tube 5 can be activated. It goes without saying that the automatic valve _V1 of the backwashing siphon pipe 5, which is not activated in this operation, remains closed. Also, even after startup, the automatic valve
When V ₁ and automatic valve V ₂ are opened, for example, 4 to 4
Since a negative pressure of 5 m H ₂ O is generated, the water in the backwash drainage retention conduit 16 can be sucked up by the suction and drainage pipe 23, and when the water level in the water tank 19 reaches the high water level A, the automatic valve is automatically activated. V ₂ closes.

By making the interior of the water tank 19 unique in this way, when starting the backwashing siphon tube 5 for the second time and thereafter, there is no need to perform the same operation as the first time, and the operation is linked to the water surface detector 25. The backwashing siphon pipe 5 can be easily activated only by switching the automatic valve V ₂ and the automatic valve V ₁ .

In addition, by branching and communicating the water flow siphon pipe 22 with the communication pipe 20 via the automatic valve V ₄ , there is no need to perform the same operations as the first time when starting the system from the second time onwards. , it can be started easily by simply switching the automatic valve V ₄ , and there is no need to _separately install a siphon stop automatic release valve. can be used to stop the siphon. Note that the air discharge valve _V5 and the inflow valve _V6 are basically always closed when starting and stopping each siphon pipe from the next time onwards.

The method for starting and stopping the backwashing siphon pipe of the present invention is to discharge water from the water tank with a water head difference that is larger than the water head difference in the backwashing siphon pipe, and to suck air in the backwashing siphon pipe that communicates with the water tank. The method was to start the siphon, open the siphon stop automatic release valve, introduce air into the backwash siphon pipe, and stop the siphon.
There is no need for a special power source such as a vacuum pump, and the siphon can be reliably started or stopped simply by opening and closing a small-diameter automatic valve, resulting in low production and operation management costs, and simple and reliable operation. can start and stop the siphon.

In addition, water can be filled into the water tank by sucking it up into the tank through the suction and drainage pipe using the negative pressure generated by the activation of the backwash siphon pipe, so it is possible to increase the amount of water drained from the water tank. do not have.

Furthermore, by making the inside of the water tank have a unique structure, it is possible to omit providing an automatic valve having a relatively large diameter in the intake/discharge pipe.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a self-cleaning gravity-type filtration device using a method for starting and stopping a backwashing siphon pipe according to an embodiment of the present invention, and FIG. It is an enlarged explanatory diagram. 1...Gravity filtration device, 2...Raw water inlet, 3...
Water pond, 4... Raw water distribution room, 5... Backwash siphon pipe, 6... Floor, 7... Support floor, 8... Super water collection room,
9... Overwater drain, 10... Overwater outflow drain, 11... Overflow weir, 12... Backwash drainage gutter, 13... Backwash drainage inlet chamber,
14... Partition wall, 15... Raw water inflow chamber, 16... Backwash wastewater retention culvert, 17... Water seal weir, 18... Backwash wastewater outflow culvert,
19... Water tank, 20... Communication pipe, 21... Supply pipe, 22
...Water flow siphon pipe, 23...Suction and drainage pipe, 24...
Raw water pipe, 25... Water surface detection meter, 26... Water surface detection meter,
27...water seal weir, 28...exhaust pipe, 29...outer cylinder pipe, 3
0...Water flow port, 31...Waterway, _V1 , _V2 , _V4 ...Automatic valve, _V3 ...Siphon stop automatic release valve, _V5 ...Air discharge valve, _V6 ...Inflow valve.

Claims (1)

[Claims] 1 A plurality of filter basins 3 are partitioned into a floor 6 and a backwash wastewater inflow chamber 13 by a partition wall 14, and are installed adjacent to and separated from the backwash wastewater inflow chamber 13, so that the backwash water in the floor 6 overflows. a common backwash drainage retention conduit 16 that maintains a water level below the water level where the backwash water from the floor 6 overflows; The water channel 9, each backwash wastewater inflow chamber 13, and the common backwash wastewater retention channel 16 are communicated with each other by having a bent part above the water level of the filter basin 3, and both ends thereof are water-sealed. The water in the backwash wastewater inflow chamber 13 is discharged by the backwash siphon pipes 5,
In a gravity-type filtration device in which excess water is caused to flow back to the floor 6 by the water head held by the excess water conduit 9, the water surface of the backwash wastewater inflow chamber 13 when trying to start the backwash siphon pipe 5 and , the distance H ₁ from the top of the backwashing siphon pipe 5, and the distance H 2 between the low level water level in the water tank 19 and the water seal level in the backwash wastewater retention conduit 16 of the suction/drainage pipe 23 attached to the water tank 19, which will be described later _. becomes the relationship H ₁ < H ₂ , and
Distance H ₅ between the high level water level in the water tank 19 and the water seal water level of the suction and drainage pipe 23, and the backwashing siphon pipe 5
Distance between the top of the water surface and the water surface of the backwash drainage retention channel 16 H ₄
A sealed water tank 19 is installed so that H ₅ <H ₄ , and the upper part of each backwashing siphon pipe 5 and the water tank 19 are connected with a common communication pipe 20. The communication pipe 20 is provided with a common automatic valve V ₂ , a common siphon stop automatic release valve V ₃ , and an automatic valve V ₁ for each backwash siphon pipe in order from the one closest to the water tank 19 . Water surface detection meter 25 that detects high level water level of
In addition, the automatic valve V ₂ is linked to the water level detector 25, and the water tank 19 is provided with an intake/drain pipe 23 whose lower end is sealed with water and whose upper end penetrates the water tank 19 and opens within the water tank 19. In addition, there is a water flow port 3 which has a larger inner diameter than the suction and drainage pipe 23 and is located below the opening of the suction and drainage pipe 23 in the water tank 19.
The outer cylindrical pipe 29 with a sealed upper part having a diameter of 0.
It is fixed in the water tank 19 so as to cover the suction and drainage pipe 23 in the water tank 19, and an exhaust pipe 28 having an air discharge valve _V5 consisting of an automatic valve or a manual valve is connected to the upper part of the outer cylindrical pipe 29. a supply pipe 21 having an inlet valve V ₆ consisting of an automatic valve or a manual valve,
And the capacity of the water tank 19 is increased so that when the water in the water tank 19 is discharged from the suction/drainage pipe 23 from the high water level to the low water level, the air present inside the backwashing siphon pipe 5 and the communication pipe 20 is By suctioning, the water in the backwashing drainage inflow chamber 13 is sucked up to a capacity that allows the backwashing siphon pipe 5 to start, and when starting and stopping one of the plurality of backwashing siphon pipes 5, When starting the backwashing siphon pipe 5, the automatic valve
V ₂ , siphon stop automatic release valve V ₃ , inflow valve V ₆ is opened to fill the water tank 19 with water, and when the water level reaches the high level water level, automatic valve V ₂ is closed and inflow valve V ₆ , Close the siphon stop automatic release valve _V3 , then open the automatic valves _V1 and _V2 of the backwashing siphon pipe 5 to be started,
Then, the automatic valve V ₁ of the other backwashing siphon pipe 5 is closed, and the air discharge valve V ₅ is opened to discharge the water in the water tank 19 from the suction and drainage pipe 23 according to the head difference, and immediately after that, the air discharge valve V ₅ is closed. By starting the backwashing siphon pipe 5, and opening the automatic valves V ₁ and V ₂ of the backwashing siphon pipe 5 which are activated even after starting, the backwashing siphon pipe 5 is activated. Water is sucked up from the suction and drainage pipe 23 by the negative pressure generated in the upper part, and when the water level reaches the above-mentioned high level, the automatic valve V ₂ is closed to retain the water in the water tank 19, and the water in the water tank 19 is is used as starting water for the next backwashing siphon pipe 5, and while the automatic valve _V1 of the backwashing siphon pipe 5 that is running is opened, the siphon stop automatic release valve _V3 is opened and the backwashing siphon pipe 5 is started. 5, and when starting the next backwashing siphon pipe 5, close the siphon stop automatic release valve _V3 , and close the automatic valve _V1 and automatic valve of the backwashing siphon pipe 5 to be started. Open V ₂ ,
Then, the automatic valve V ₁ of the other backwashing siphon pipe 5 is closed, and the water in the water tank 19 sucked up from the suction and draining pipe 23 is discharged according to the water head difference, thereby starting the backwashing siphon pipe 5. The automatic valves V ₁ and V ₂ of the activated backwashing siphon pipe 5 are opened, and water is sucked up from the suction and drainage pipe 23 by the negative pressure generated at the upper part of the backwashing siphon pipe 5, and the water level reaches the above level. Automatic valve when water level reaches high level
V ₂ is closed to retain water in the water tank 19, and the water in the water tank 19 is transferred to the siphon pipe 5 for backwashing from next time onwards.
After that, it is used as starting water for starting the backwashing siphon pipe 5 for the next time and for starting the backwashing siphon pipe 5.
A method for starting and stopping a siphon tube for backwashing in a gravity-type filtration device, characterized by sequentially repeating the following steps: