V-type filter and its backwashing method

Abstract

The present invention provides a V-type filter and an anti-backwashing method thereof. The anti-backwashing method includes an air anti-backwashing step, an air-water mixed anti-backwashing step, and a water anti-backwashing step, and determines whether the water anti-backwashing step meets the end condition; wherein, meeting the end condition means meeting one of the following conditions: the water anti-backwashing time reaches the personalized preset time and the turbidity value of the sewage discharged is lower than the preset turbidity value; or the water anti-backwashing time is greater than the overtime alarm value; wherein, the personalized preset time is less than or equal to the system default preset time, and the system default preset time is less than or equal to the overtime alarm value; if the judgment result is yes, the water anti-backwashing step ends. The anti-backwashing method can ensure that each filter body is thoroughly washed and achieve a water-saving effect at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of backwashing of filter tanks, and more specifically, to a V-shaped filter tank and its backwashing method. Background Art

[0002] The V-shaped filter tank gets its name because the inlet troughs on both sides are designed in the shape of the letter V. It is a deep homogeneous filter media or uniform particle size filter tank, combining the advantages of rapid filtration tanks and coarse filter media filter tanks. Due to the advantages of strong pollutant interception capacity, good filtered water quality, relatively fast filtration rate, long operation cycle, ideal backwashing effect, and suitability for automation transformation and operation, the V-shaped filter tank process has been widely applied in the production of domestic water treatment plants. It is a key link in the production of domestic drinking water, guarding the last pass before the raw water to be filtered enters the clear water tank, and is closely related to the water quality of the water leaving the plant.

[0003] See Figure 1 and Figure 2 , the V-shaped filter tank includes a total inlet channel and a plurality of filter tank bodies 12. Each filter tank body 12 includes a V-shaped trough 121, a filter tank part 122, a drainage channel 125, long-stem filter nozzles 123, homogeneous filter media 124, etc. A sewage discharge port 1251 is opened on the end wall of the drainage channel 125. The filtering working principle of the V-shaped filter tank is as follows: The raw water to be filtered flowing in from the total inlet channel through the inlet valve 13 overflows the weir opening 14 and enters the two-side V-shaped troughs 121 through the side holes 120 on both sides. It enters the interior of the filter tank part 122 simultaneously from the water distribution holes 1211 at the bottom of the V-shaped trough 121 and the trough weir 1212 of the V-shaped trough 121. After being filtered by the homogeneous filter media layer 124, it becomes clear water. The clear water flows from the filter nozzles 123 to the bottom space 16, converges from the square holes 18 into the air-water distribution pipe channel 15, and finally flows through the pipe gallery water seal well, the outlet weir, and the clear water pipe 19 to the clear water tank.

[0004] If the water quality data such as the turbidity of the raw water to be filtered does not change significantly, it is customary in the industry to set fixed backwashing time values (for example: air backwashing for 60 seconds, air-water mixed backwashing for 420 seconds, water backwashing for 420 seconds) for each stage (air backwashing, air-water mixed backwashing, water backwashing) of the backwashing process of each V-shaped filter tank, and it remains fixed for a quite long period. However, after years of use, the decay of the working performance of each filter tank varies from tank to tank. Therefore, setting a unified and fixed backwashing time value for each V-shaped filter tank will result in the dual drawbacks of being neither conducive to thoroughly washing each filter tank clean nor possibly causing excessive backwashing of some filter tanks, leading to a large waste of water resources. Summary of the Invention

[0005] The first object of the present invention is to provide a backwashing method for a V-shaped filter tank that can ensure that each filter tank body is thoroughly washed clean while achieving a water-saving effect.

[0006] The second object of the present invention is to provide a V-type filter tank adopting the above backwashing method.

[0007] To achieve the above first object, the present invention provides a backwashing method for a V-type filter tank. The backwashing method includes an air backwashing step, an air-water mixed backwashing step, and a water backwashing step, and determines whether the water backwashing step meets the end condition. Among them, meeting the end condition means meeting one of the following conditions: the water backwashing time reaches the personalized preset time and the turbidity value of the sewage discharged is lower than the preset turbidity value; or the water backwashing time is greater than the overtime alarm value. Among them, the personalized preset time is less than or equal to the system default preset time, and the system default preset time is less than or equal to the overtime alarm value. If the judgment result is yes, the water backwashing step ends.

[0008] As can be seen from the above solution, the end condition of the water backwashing step is to simultaneously meet condition A "the water backwashing time reaches the personalized preset time" and condition B "the turbidity value of the sewage discharged is lower than the preset turbidity value", or meet condition C "the water backwashing time is greater than the overtime alarm value". In this way, it can not only ensure that the filter tank body obtains at least the personalized preset backwashing time, but also avoid the phenomenon that the backwashing cannot be stopped due to the failure of the turbidity meter. It effectively prevents water quality safety accidents such as incomplete and unclean flushing of the filter tank caused by misjudgment of the system due to factors such as abnormal turbidity meter or signal feedback failure. In addition, by setting the water backwashing time personalized, it can not only ensure that each filter tank body is thoroughly flushed, but also reduce unnecessary consumption of backwashing water volume.

[0009] A preferred solution is that the personalized preset time is less than the system default preset time, and the system default preset time is less than the overtime alarm value.

[0010] A further solution is that the V-type filter tank includes a turbidity meter and a plurality of filter tank bodies. The plurality of filter tank bodies are arranged in parallel, and each filter tank body is provided with a sewage discharge port. The turbidity meter is used to real-time monitor the turbidity value of the sewage discharged from the sewage discharge port.

[0011] A still further solution is that the V-type filter tank further includes a sewage collection channel. Each sewage discharge port is communicated with the sewage collection channel, and the turbidity meter is installed in the sewage collection channel.

[0012] It can be seen that the water backwashing stage of the V-type filter tank is the link with the largest water consumption in the backwashing process and also accounts for a relatively large proportion of the self-use water volume of the water plant. Therefore, installing a turbidity meter in the sewage collection channel where the sewage from the backwashing sewage discharge channels of all filter tank bodies flows out, which is used to real-time monitor the turbidity value of the sewage discharged during the water backwashing stage. This method can accurately judge whether the filter tank body is thoroughly backwashed and use this as an important basis for ending the water backwashing stage. Compared with the existing method of using a fixed backwashing time, it is more reasonable, effectively reduces the self-use water volume of the water plant, and achieves the purpose of energy conservation and consumption reduction.

[0013] To achieve the above second objective, the present invention provides a V-shaped filter. The V-shaped filter adopts the above backwashing method. The V-shaped filter includes a sewage collection channel, a turbidimeter, and a plurality of filter body units. The plurality of filter body units are arranged in parallel. Each filter body unit is provided with a sewage discharge port, and each sewage discharge port is communicated with the sewage collection channel. The turbidimeter is installed in the sewage collection channel for real-time monitoring of the turbidity value of the sewage discharged.

[0014] A preferred solution is that the V-shaped filter further includes a drain valve. The drain valve is arranged at the sewage discharge port for opening or closing the sewage discharge port. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of the filter body unit of the existing V-shaped filter.

[0016] Figure 2 is a schematic structural diagram of the existing V-shaped filter.

[0017] Figure 3 is a schematic structural diagram of the first perspective of the V-shaped filter according to the embodiment of the present invention.

[0018] Figure 4 is a schematic structural diagram of the second perspective of the V-shaped filter according to the embodiment of the present invention.

[0019] Figure 5 is a backwashing flow chart of the V-shaped filter according to the embodiment of the present invention.

[0020] The present invention will be further described below in conjunction with the drawings and embodiments. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Referring to Figure 3 and Figure 4 , the V-shaped filter includes an inlet main channel 4, a sewage collection channel 1, a turbidimeter 2, a drain valve, and a plurality of filter body units 3. The plurality of filter body units 3 are arranged in parallel. Each filter body unit 3 is communicated with the inlet main channel 4. The extending direction of the inlet main channel 4 is parallel to the arrangement direction of the filter body units 3. The filter body unit 3 includes long-stem filter heads, filter media, and two V-shaped grooves 32 arranged in parallel, a drainage channel 33, and two filter sections 34. The drainage channel 33 is located between the two filter sections 34, and the filter sections 34 are located between the drainage channel 33 and the V-shaped grooves 32. A plurality of long-stem filter heads are arranged at the bottom of the filter sections 34. The long-stem filter heads are used for distributing backwashing water and gas. The filter media are arranged in the filter sections 34. An air-water distribution pipe channel is further provided at the bottom of each drainage channel 33.

[0022] Each filter body 3 is provided with a sewage discharge port 31, and the sewage discharge port 31 is located on the end wall of the drainage channel away from the inlet main channel. Each sewage discharge port 31 is communicated with the sewage collection channel 1. A turbidimeter 2 is installed in the sewage collection channel 1 to monitor the turbidity value of the sewage discharged in real time. A drain valve is arranged at the sewage discharge port 31 to open or close the sewage discharge port 31.

[0023] In the V-shaped filter, each filter body 3 is individually backwashed, that is, each backwashing only flushes one filter body 3. During backwashing, the inlet valve is closed, but a part of the water in the inlet main channel 4 still flows into the filter body 3 from the normally open square holes on both sides, flows from one side of the V-shaped groove 32 to the other side of the drainage channel 33, forming surface flushing. Then the drain valve is opened to discharge the water on the pool surface from the sewage discharge port 31 of the drainage channel 33 until the water surface of the filter part 34 is flush with the top of the V-shaped groove 32.

[0024] The backwashing process includes an air backwashing step, an air-water mixed backwashing step, and a water backwashing step. Regarding the flushing time values at each stage of the system backwashing process, the operator can conveniently set or modify the backwashing time in a personalized and differentiated manner through a human-machine interface or a touch screen according to the working performance of each filter body 3 to be backwashed. This backwashing time is a personalized preset time. According to the differences in the working performance of the filters, setting the flushing time at each stage of the backwashing process of the filters in a personalized manner can not only ensure that each filter body 3 is thoroughly flushed, but also reduce unnecessary consumption of backwashing water volume.

[0025] See Figure 5 , the backwashing method of the V-shaped filter includes the following steps.

[0026] Step S1, determine whether to select to backwash a certain filter body 3. If so, execute step S2.

[0027] Step S2, pre-filtering before backwashing.

[0028] Step S3, determine whether the pre-filtering time before backwashing is over. If so, execute step S4.

[0029] Step S4, pre-sewage discharge before backwashing.

[0030] Step S5, determine whether the pre-sewage discharge time before backwashing is over. If so, execute step S6.

[0031] Step S6, air backwashing: open the air inlet valve, start the air supply equipment, air enters the bottom of the filter part 34 evenly through the small holes in the upper part of the air-water distribution pipe channel, is ejected by the long-stem filter head, scrubs the impurities on the surface of the filter material and suspends them in the water, and is washed into the drainage channel 33 by the surface flushing water.

[0032] Step S7, determine whether the air backwashing time is over. If so, execute step S8.

[0033] Step S8, air-water mixed backwashing: While performing air backwashing, start the backwashing water pump and open the backwashing water valve. The backwashing water also enters the air-water distribution pipe channel. The air and water flow into the bottom water distribution area of the filter section 34 through small holes and square holes respectively, and evenly enter the filter section 34 through long-stem filter heads. The filter media is further washed, and the surface flushing continues.

[0034] Step S9, determine whether the air-water mixed backwashing time has ended. If so, execute Step S10.

[0035] Step S10, water backwashing: Perform single water backwashing, and the surface flushing continues. Finally, all impurities in the water are flushed into the drainage channel 33. The sewage in the drainage channel 33 flows from the sewage outlet 31 to the sewage collection channel 1, and the turbidimeter 2 monitors the turbidity value of the sewage discharged in the sewage collection channel 1 in real time.

[0036] Step S11, determine whether the end condition F is satisfied, F = A * B + C; where A is that the water backwashing time reaches the personalized preset time; B is that the turbidity value of the discharged sewage is lower than the preset turbidity value; C is that the water backwashing time is greater than the overtime alarm value. Specifically, as long as one of the following two conditions is satisfied, it is confirmed that the end condition F is satisfied: The first condition is: the water backwashing time reaches the personalized preset time and the turbidity value of the discharged sewage is lower than the preset turbidity value; the second condition is: the water backwashing time is greater than the overtime alarm value.

[0037] Preferably, the personalized preset time is less than the system default preset time, and the system default preset time is less than the overtime alarm value; if the judgment result of Step S11 is yes, the water backwashing step ends.

[0038] For example, when backwashing the No. 1 filter body 3, the personalized preset time of the water backwashing step is set to 380 seconds, and the system default preset time is 420 seconds. When the No. 1 filter body 3 enters the water backwashing step and the water backwashing time is 390 seconds, if the turbidity value of the discharged sewage is lower than the preset turbidity value at this time, that is, earlier than the system default preset time of the water backwashing, the backwashing step can be ended in advance, and 30 seconds of the water volume of the backwashing water flowing out can be saved. If the water backwashing time has exceeded 420 seconds, but the turbidity value of the discharged sewage is still higher than the preset turbidity value at this time, it means that more sludge is flushed out of the filter body 3 by the water backwashing, and the filter body 3 is still not washed clean, then the system continues to execute the water backwashing step to ensure that the filter body 3 can be thoroughly washed. When the water backwashing time reaches the overtime alarm value, the water backwashing step ends, which can stop the backwashing step when problems such as large measurement errors or low values occur in the turbidimeter 2.

[0039] As can be seen from the above, the end condition of the water backwashing step is that both condition A "the water backwashing time reaches the personalized preset time" and condition B "the turbidity value of the sewage discharge is lower than the preset turbidity value" are satisfied, or condition C "the water backwashing time is greater than the overtime alarm value" is satisfied. In this way, it can not only ensure that the filter tank body obtains at least the personalized preset backwashing time, but also avoid the phenomenon that the backwashing cannot be stopped due to the failure of the turbidity meter. It effectively prevents the system from misjudging and ending the backwashing in advance due to factors such as abnormal turbidity meter or signal feedback failure, resulting in water quality safety accidents where the filter tank is not thoroughly washed and is not clean. In addition, by setting the water backwashing time personalized, it can not only ensure that each filter tank body is thoroughly washed, but also reduce the unnecessary consumption of backwashing water volume.

[0040] In addition, the personalized preset time can also be equal to the system default preset time. The system default preset time can also be equal to the overtime alarm value. The above changes can also achieve the purpose of the present invention.

[0041] Finally, it should be emphasized that the above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. Backwashing method for V-shaped filter, the backwashing method comprising an air backwashing step, an air-water mixed backwashing step and a water backwashing step; Characterized in that: Determine whether the water backwashing step meets the end condition, wherein meeting the end condition means meeting one of the following conditions: the water backwashing time reaches the personalized preset time and the turbidity value of the sewage discharged is lower than the preset turbidity value; or, the water backwashing time is greater than the overtime alarm value, and the personalized preset time is set according to the working performance difference of the filter; Wherein, the personalized preset time is less than the system default preset time, and the system default preset time is less than the overtime alarm value; If the judgment result is yes, the water backwashing step ends.

2. The backwashing method according to claim 1, characterized in that: The V-shaped filter comprises a turbidimeter and a plurality of filter bodies, the plurality of filter bodies are arranged in parallel, each filter body is provided with a sewage discharge port, and the turbidimeter is used for real-time monitoring of the turbidity value of the sewage discharged from the sewage discharge port.

3. The backwashing method according to claim 2, characterized in that: The V-shaped filter further comprises a sewage collection channel, each sewage discharge port is communicated with the sewage collection channel, and the turbidimeter is installed in the sewage collection channel.

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