JPH03296404A - Method for washing filter tank - Google Patents

Abstract

PURPOSE:To get high washing effect using a small amount of washing water by repeating by turns washing water supply to the filter tank where filter media are set and interruption of the water supply. CONSTITUTION:Into a filter tank 8 where filter media are set washing water is fed and stopped repeatedly by turns. Duration for feeding the washing water is taken as time length required for filtration efficiency to reach its peak value, while duration for interruption of the water supply is taken as the time length required for sedimentation of dirts and filter media stirred up in the filter tank. In this way the whole washing process consists of individual washing cycles being performed each in relatively short time. Each cycle is performed till the moment when max. washing efficiency is achieved. Therefore, an effective washing of the filter media can be realized at every cycle. It is hence possible to carry out effective washing, consuming a much smaller amount of the water as compared with conventional methods for continuous washing.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for cleaning a filtration tank included in a filtration device for purifying bathtub water, for example. However, the object to be filtered is not limited to bath water.

<Conventional technology> Conventionally, in a filtration device installed in a bathtub, etc., a circulation pump sucks out bathwater from the bathtub and passes the bathwater from the top to the bottom of the filtration tank, thereby removing the water contained in the bathtub water. After cleaning and removing dirt such as dirt, dust, and impurities, this clean water is returned to the bathtub.

As you repeat this type of filtration and cleaning of bathtub water, dirt accumulates on the filter medium and the filtration capacity gradually decreases. This is done by passing wash water (bath water or tap water) from the bottom to the top of the tank. Conventionally, the wash water is continuously passed through the filter tank for a certain period of time.

<Problems to be Solved by the Invention> By the way, it has been pointed out that the conventional cleaning method requires a huge amount of water and is uneconomical. Moreover, after a certain period of time has elapsed from the start of cleaning, there is a limit to the cleaning effect, as it becomes difficult to remove the filter medium and the dirt in the filter medium.

In addition, if you increase the flow rate of cleaning water (amount per unit time),
Although it is possible to improve the cleaning effect even a little, the amount of water used increases further, leading to an increase in running costs, and the filter medium becomes more likely to leak outside.

The present invention was devised in view of these circumstances, and an object of the present invention is to provide a high cleaning effect with a small amount of water.

Means for Solving the Problems> In order to achieve the above objects, the present invention has the following configuration.

The method for cleaning a filtration tank of the present invention is a method for cleaning a filtration tank in which a filter medium is stored, and is characterized by alternately repeating introduction of washing water into the filtration tank and stopping the introduction of washing water. .

It is preferable that the introduction time of the washing water is the time required for the washing efficiency to reach its peak, and the introduction stop time of the washing water is the time required for the dirt and filter material flying up in the filtration tank to settle. Further, when the introduction of washing water is stopped, a predetermined amount of water in the filtration tank may be drained.

Effect> Focusing on the fact that the time from the start of cleaning until the cleaning efficiency reaches its peak is relatively short, we decided to perform the short cleaning operation in multiple steps.

In other words, even if the cleaning is performed for a short time, foreign matter can be efficiently removed at the initial stage of each cleaning operation. Moreover,
Because it cleans in a short time, less water is used than before.

Further, if a predetermined amount of water in the filter tank is drained when cleaning is stopped, the resistance to passage of the cleaning water at the initial stage of cleaning is reduced, and the filter medium can be cleaned more efficiently.

Here, before describing the examples, a confirmation test of the filter medium restoration performance by washing, which was the basis for constructing the examples, will be described.

Figure 2 shows the schematic configuration of the test equipment.
is a bathtub, 34 is a hair catcher, 36 is a circulation pump, 3
B is a transparent filtration tank, 38a is an upper inlet/outlet of the transparent filtration tank 38, 38b is a lower inlet/outlet, 40 is a filter medium, 50 is a gas turbine, 52 is a pump, 54 is a suction port, 56 is a clean water flow port, 58 is a drain port, 60.62, 64.66 are valves, and 68 is a drainage container.

The transparent filter tank 38 has a height of 750 mm and a diameter of 19 mm.
Using an 8mm cylindrical piece, 100mm of gravel and 375mm of ceramic beads were placed on the perforated partition plate as filter media.
It is loaded and stored up to a height of m.

In the filtration device having the above structure, the flow rate to the filtration tank 38 during filtration is 301/min, and the flow rate during cleaning is 321/min, which varies depending on the piping resistance.

[Filtration process]

Foreign matter (iron rusted rice) is mixed into the bathtub 32, and the valve 60
．． When only the valve 66 is opened and the circulation pump 36 is driven, the bath water in the bathtub 32 flows from the suction port 54 to the hair catcher 3.
4 to circulation pump 36 and valve 60. The water flows into the filtration tank 38 from the upper entrance/exit 38a.

Thereby, foreign substances contained in the bathtub water are removed by the filter medium 40 and the bathtub water is cleaned. This clean water is returned to the bathtub 32 from the clean water flow port 56 via the valve 66 at the lower entrance/exit.

This filtration was continued until the water in the bathtub 32 became almost transparent as determined by visual observation.

[Washing process]

Pump 52 is activated by closing valves 60.66 and opening valves 62.64. As a result, 50
Washing water is introduced from the lower inlet/outlet 38b of the filtration tank 38 through the pump 52 and the valve 64, and the impurities adhering to the filter medium 40 flow out from the upper inlet/outlet 38a of the filtration tank 38, and are then passed through the valve 62. Drain container 6 through drain port 58
It is stored in 8.

This cleaning was performed three times, and the results of turbidity estimation by visual observation inside the transparent filtration tank 38 and turbidity measurement using a turbidity meter of the waste water inside the drainage container 68 are shown in Figure 3 and the table below. show,
Note that measurements using a turbidimeter were performed every 30 seconds.

■　First cleaning test Washing was performed continuously for 5 minutes and 30 seconds.

At this time, visual observation of the transparent filtration tank 38 revealed that 6 to 7 seconds after the start of cleaning, foreign matter suddenly rose up from the filter medium 40 and was flowed out, but it was confirmed that it became almost transparent after 45 to 50 seconds. . On the other hand, when the water stored in the drainage container 68 was measured with a turbidity meter, the turbidity was 0.1 or less 5 minutes after the start of cleaning.

(2) Second Washing Test After the first washing test was completed, the filter medium 40 and the foreign matter floating up in the filter tank 38 were waited for to settle down, and then washing was continued for 5 minutes. At this time,
Visual observation revealed that it was quite cloudy, although it was not the first time, but it was confirmed that it became almost transparent after 30 to 35 seconds. The turbidity was 0.25 when measured using a turbidity meter 30 seconds after the start of washing. In addition, the reason why the measurement was stopped after 3 minutes in FIG. 3 is because the turbidity meter used in the test cannot accurately measure 0.1 or less.

(3) Third cleaning test Continuous cleaning was performed for 5 minutes in the same manner as the second cleaning test. At this time, visual observation showed that it was almost transparent from the beginning of cleaning. The turbidity measured by a turbidity meter was 0.2 30 seconds after the start of cleaning.

From the above table, it was found that the degree of turbidity due to washing becomes severe within 45 seconds after the start of washing. In other words,
It can be assumed that it is more effective to perform backwashing for 45 seconds or less three times intermittently than to perform continuous washing for 5 minutes or more. That is, as can be seen from Figure 3 and the table above, the first washing was carried out for 45 seconds until the turbidity became almost transparent by visual inspection, and the second washing was carried out for 30 seconds until the turbidity reached 0.25 on the turbidity meter. It has been found that it is sufficient to carry out the third washing for 20 seconds, and that the inside of the filter tank 38 can be cleaned to an almost transparent state by performing the third washing for 20 seconds.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 is a block diagram showing the filtration device.
is a bathtub, 4 is a hair catcher, 6 is a circulation pump, 8 is a filtration tank, 10 is a filter medium, 12 is an automatic air release valve, ■1 to V5
are the first to fifth electric valves, and the portions excluding the bathtub 2 constitute a filtration device. The hair catcher 4 removes hair and large debris contained in hard bathtub water from the bathtub 2.

A suction side of a circulation pump 6 is connected to a suction port 14 provided in the bathtub 2 via a hair catch ±4. The piping system on the discharge side of the circulation pump 6 is branched into two at a three-way switching part a, one is connected to the upper inlet/outlet 8a of the filtration tank 8 via the first electric valve v1, and the other is connected to the upper inlet/outlet 8a of the filtration tank 8. It is pipe-connected to the lower inlet/outlet 8b of the filtration tank 8 via an electric valve (2). First electric valve ■1 and upper entrance/exit 8a
A three-way switching section C is provided in the piping system between the second electric valve v2 and the lower inlet/outlet 8b, and the three-way switching section C and is the third
The electric valve v3 and the fourth electric valve v4 are connected via piping.

A three-way switching section d is provided in the piping system between the fourth electric valve ■4 and the three-way switching section C, and this three-way switching section d and the clean water flow port 16 to the bathtub 2 are connected to the fifth electric pulp v5. Piping is connected via. A three-way switching section e is provided in the piping system between the third electric pulp v3 and the fourth electric valve v4, and a drain pipe 18 is connected to the three-way switching section e.

A perforated partition plate 20 is provided at the bottom of the filtration N8, and a large number of filter media 10 are loaded and stored in the upper part of the partition plate 20.
An upper entrance/exit 8a opens above the top surface, and a lower entrance/exit 8b opens below the perforated partition plate 20.

22 is a sequence controller, which controls the circulation pump 6 and the first to fifth electric valves Vl to v5 in a predetermined order. Reference numeral 24 denotes a remote control operation unit attached to the wall inside the bathtub, and is configured to give commands for each mode to the sequence controller 22.

In addition, in the first embodiment, the fourth electric valve v4 and the automatic air bleed valve! 2 is not operated, so these may be omitted.

Next, the operation of the filtration device having the above configuration will be explained.

[Filtration mode]

When the sequence controller 22 receives a filtration mode command from the remote control operation unit 24, the sequence controller 22 operates the first electric valve v1.
and opens the fifth electric valve v5. Other electric valve V2. V3. V4 remains closed. Next, the sequence controller 22 drives the circulation pump 6. As a result, as shown by the thin solid line arrow, the bath water in the bathtub 2 is sucked out from the suction port 14, and the hair catching process 4
, circulation pump 6, three-way switching section a, first electric valve v1
and the upper inlet/outlet 8a of the filtration tank 8 via the three-way switching part.
It flows in from.

The bathtub water passes through the filter tank 8 from top to bottom, and while passing through the filter medium 10, dirt (dirt, dirt, etc.) contained in the bathtub water is removed.
impurities, etc.) are removed and purified. The clean water is returned to the bathtub 2 from the clear water return port 16 via the lower entrance/exit 8b, the three-way switching parts c and d, and the fifth electric valve v5.

When the filtration mode command is released from the remote controller 24 or when the sequence controller 22 counts up a predetermined cleaning time, the circulation pump 6 is stopped.

As such filtration mode is repeated, dirt accumulates in the filtration tank 8 (.

[Washing mode]

■ The sequence controller 22 is connected to the remote control operation section 2.
When the command for the cleaning mode is received from 4, the first electric valve (1) and the fifth electric valve (5) are closed, and the second electric valve (v2) and the third electric valve (v3) are opened. The fourth electric valve v4 remains closed.Next, the sequence controller 22 drives the circulation pump 6 and performs the first cleaning for a predetermined time. The water in the bathtub 2 is sucked out as cleaning water from the suction port 14, and is passed through the hair catcher 4, the circulation pump 6, the three-way switching section a, the second electric valve v2, and the three-way switching section C to the lower entrance/exit of the filtration tank 8. 8b.

The cleaning water flowing in from the lower entrance/exit 8b is passed through the perforated partition plate 2
0, passes through the filter medium 10 from bottom to top, and reaches the upper entrance/exit 8a, but while passing through the filter medium 10, dirt is successively separated from the filter medium 10. The cleaning water containing dirt is discharged to the outside from the drain pipe 18 via the upper entrance/exit f3a, the three-way switching section S, the third electric valve v3, and the three-way switching section e.

The sequence controller 22 stops the circulation pump 6 after counting the first cleaning time T1. This first cleaning time TI is set to approximately 45 seconds, which is a period until the peak of cleaning has passed, as confirmed in a test. During washing, the filter medium 10 in the upper part of the filter tank 8 flies up, but the first washing time T1 is short and the flow rate of the washing water (for example, 321/sin) does not reach that much. There is no flow out from the filter tank 8, and when the circulation pump 6 is stopped, the filter medium 10 and dirt that have flown up settle down, and the predetermined waiting time T
After 20 seconds (approximately 20 seconds), it completely sinks and stands still.

(i) When the sequence controller 22 counts up the waiting time T while the circulation pump 6 is stopped, the sequence controller 22 drives the circulation pump 6 again and performs the second cleaning for a predetermined period of time.
This further promotes the separation of dirt from the filter medium 1O and from the filter medium 1O. When the sequence controller 22 counts up the second cleaning time T (approximately 30 seconds), it stops the circulation pump 6 and waits for the count up of the waiting time T0 until the filter medium 10 and the dirt settle and stand still.

■ Waiting for the count-up, the sequence controller 22 drives the circulation pump 6 again to perform the third cleaning for a predetermined time, and the third cleaning time Ts (approximately 2
0 seconds), after stopping the circulation pump 6, the second electric valve V2 and the third electric valve v
Close valve 3.

Through the three separate washings described above, dirt is almost completely separated from the filter medium IO.

In conventional continuous cleaning, for example, backwashing is performed for 6 minutes at a cleaning flow rate of 321/win, so the amount of water used for this cleaning is 32X6-1927, but in the case of this example, Tl-45 seconds, Tl-
Since it is 30 seconds and T3 is 20 seconds, the amount of water used is 32X (45+30+20)/601IT501, which is less than one third.

However, the filter medium cleaning efficiency has improved from 90% to 97%.
It can be increased up to 98%.

Next, the cleaning operation of the filtration device according to the second embodiment will be explained. In this second embodiment, the fourth electric valve v4 and the automatic air bleed valve 12 are operated.

■' Similarly to ■ in the first embodiment, the sequence controller 22 controls the electric valve V2. After opening the valve V3 and driving the circulation pump 6 to wash the filtration tank 8 in the flow path indicated by the thick solid line arrow for the first washing time TI (approximately 45 seconds), the circulation pump 6 is stopped and the waiting time is Wait for 20 seconds (approximately 20 seconds).

■' The action controller 22 closes the second electric valve v2 and the third electric valve ■3, and closes the fourth electric valve v2.
Open electric valve v4. Note that the first electric valve v1 and the fifth electric valve v5 remain closed. By opening the fourth electric valve v4, the water in the filtration tank 8 flows through the lower inlet/outlet 8b, the three-way switching parts c and d, the fourth electric valve v4, and the three-way switching part e, as shown by the broken line arrow. and is discharged from the drain pipe 18. At this time,
The automatic air bleed valve 12 opens due to the reduced pressure inside the filtration tank 8, and air enters the filtration tank 8, thereby promoting the discharge of water from the filtration tank 8. The water in the filter tank 8 is discharged through the filter medium 10.
The water level of the filtration tank 8 is lowered to a position P where dirt such as dirt generated at a predetermined height L (30 to 40 cm if the height of the filtration tank 8 is 75 cm) is particularly significant from the top surface of the filter medium 1O. up to. When a water level sensor (not shown) or a timer detects that the water level has decreased to this position P, the fourth electric valve v4 is closed.

■'The circulation pump 6
is driven, and the second cleaning is performed for the second cleaning time Tx (approximately 3
0 seconds), the water level is lowered once to the position P where the dirt is particularly significant, and the washing is performed again, so there is less resistance to separating the dirt from the filter medium 10 by washing, and the separation is performed effectively. be able to. and,
After stopping the circulation pump 6, the second electric valve v2 and the third electric valve v3 are closed.

As a result of the above, dirt is almost completely separated from the filter medium IO.

In the case of this example, T+=45 seconds and "rz=-3° seconds, so the amount of water used for cleaning is 32x (45+
30)/60=4(1, 1961 in the case of the conventional example)
In addition, the cleaning efficiency of the filter medium is higher than that of the first embodiment, and is nearly 100%.

It should be noted that if the water level in the filter tank 8 is lowered to the position P before step 2', a -mega higher filter medium cleaning efficiency can be obtained.

<Effects of the Invention> As explained above, according to the present invention, cleaning is performed in relatively short periods of time, and the cleaning time for each time is up to the point at which the cleaning efficiency is high in terms of filter medium cleaning efficiency. ,
The filter medium can be efficiently cleaned in each cleaning, and compared to conventional continuous cleaning, the filter medium can be cleaned efficiently with a much smaller amount of water.

In addition, by draining a predetermined amount of water in the filter tank while cleaning is stopped, reducing the resistance at the initial stage of cleaning, it is possible to effectively remove foreign matter from the filter medium, making it even more efficient. This has the effect that cleaning can be performed.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a filtration device according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a test device for confirming filter medium restoration performance, and FIG. 3 is a characteristic diagram of filter medium cleaning efficiency obtained as a result of the test.

Claims (3)

[Claims] (1) A method for cleaning a filtration tank in which a filter medium is housed, the method comprising alternately repeating introduction of washing water into the filtration tank and stopping introduction of the washing water. (2) In claim (1), the introduction time of the washing water is the time required for the washing efficiency to reach its peak, and the time for stopping the introduction of the washing water is the time required for the dirt and filter media that fly up in the filtration tank to settle. A method for cleaning a filtration tank, characterized in that it takes a long time. (3) The method for cleaning a filter tank according to claim (1), characterized in that when the introduction of cleaning water is stopped, a predetermined amount of water in the filter tank is drained.