A filtration system and filtration method with backwash water recovery function

Abstract

The application belongs to the technical field of water filtration, and particularly discloses a filtering system with backwashing water recycling function and a filtering method. The filtering system comprises a filter, a first conveying pump, a second conveying pump, and a filtering water inlet pipeline, a filtering water outlet pipeline, a backwashing water inlet pipeline and a backwashing water outlet pipeline. The top of the filter is provided with an air vent. The inlet end of the second conveying pump is in communication with the space below the filter layer of the filter. The outlet end of the second conveying pump is in communication with the inlet end of the first conveying pump. The water inlet end of the filtering water inlet pipeline is in communication with the outlet end of the first conveying pump. The filtering water inlet pipeline, the filtering water outlet pipeline, the backwashing water inlet pipeline and the backwashing water outlet pipeline are all in communication with the filter. The filtering method based on the filtering system can improve the utilization rate of water resources, reduce water waste, reduce the operation cost of water treatment, and has good economic benefits and environmental protection effects.

Description

Technical Field

[0001] This invention belongs to the field of water filtration system technology, and relates to a filtration system and method with backwash water recovery function, specifically a filtration system and method that recovers water stored in the filter before backwashing. Background Technology

[0002] In the field of water treatment, especially in swimming pool and amusement pool water treatment systems, filters are key equipment for ensuring water cleanliness. Traditional filtration systems typically use particulate media filtration devices such as quartz sand filters, which physically trap and adsorb suspended solids and impurities in the water through filter media layers. To maintain the normal working efficiency of the filter, the filter media needs to be cleaned regularly, such as through backwashing and forward washing processes.

[0003] like Figure 1 As shown, during filtration, open the valves on the filter inlet pipe 11 and the filter outlet pipe 13, and close the valves on the forward flush outlet pipe 14, the backwash water inlet pipe 15, and the backwash water outlet pipe 12. After the filtered water enters the filter, it passes through the filter layer for filtration. During backwashing, close the valves on the filter inlet pipe 11, the filter outlet pipe 13, and the forward flush outlet pipe 14, and open the valves on the backwash water inlet pipe 15 and the backwash water outlet pipe 12. This allows the backwash water to enter the filter layer from below, causing the sand particles in the filter layer to expand. Through the mutual friction between the sand particles, the dirt adhering to the surface of the sand particles is scrubbed off and discharged from the filter with the water. This process lasts approximately 6-8 minutes. During the forward flushing operation, close the valves on the backwash water outlet pipe 12, the filter outlet pipe 13, and the backwash water inlet pipe 15, and open the valves on the filter inlet pipe 11 and the forward flushing outlet pipe 14. The forward flushing water that has passed through the filter layer is discharged through the forward flushing outlet pipe, for example, discharged into the municipal drainage pipe. This process lasts for about 5 to 10 minutes.

[0004] In actual operation, it was found that the water discharged during the initial backwashing stage was usually directly discharged without being effectively recycled. This practice not only wastes a large amount of clean water resources but also increases the cost of heating the pool water. This problem of low water utilization is particularly prominent against the backdrop of increasingly scarce water resources. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a filtration system with backwash water recovery function to overcome or at least partially solve the aforementioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A filtration system with backwash water recovery function includes a filter, a first delivery pump, a second delivery pump, and filter inlet pipes, filter outlet pipes, backwash water inlet pipes, and backwash water outlet pipes, all connected to the filter. The filter has a vent valve at its top, which allows the space above the filter layer in the filter to communicate with the outside atmosphere. The inlet of the second delivery pump is connected to the space below the filter layer in the filter, and the outlet of the second delivery pump is connected to the inlet of the first delivery pump. The inlet of the filter inlet pipe is connected to the outlet of the first delivery pump, the outlet of the filter inlet pipe is connected to the space above the filter layer in the filter, the inlet of the filter outlet pipe is connected to the space below the filter layer in the filter, the inlet of the backwash water inlet pipe is connected to the outlet of the first delivery pump, the outlet of the backwash water inlet pipe is connected to the space below the filter layer in the filter, and the inlet of the backwash water outlet pipe is connected to the space above the filter layer in the filter.

[0008] Preferably, the filtration system is further provided with an air inlet pipe; the air outlet of the air inlet pipe is connected to the space below the filter layer in the filter.

[0009] Preferably, the filtration system is also equipped with a liquid level sensor, which can detect changes in the liquid level in the filter.

[0010] Preferably, the filtration system also includes a water storage tank, the inlet of which is connected to the outlet of the second delivery pump, and the outlet of which is connected to the inlet of the first delivery pump.

[0011] A filtration method with backwash water recovery function, comprising using the aforementioned filtration system with backwash water recovery function for water filtration, the filtration method including:

[0012] Step S1, Filtration: Start the first delivery pump to send the water to be filtered into the filter through the filter inlet pipe. After the filtered water passes through the filter layer in the filter in the forward direction, it is discharged through the filter outlet pipe.

[0013] Step S2, backwash water recovery: Open the vent valve, start the second delivery pump, and deliver the water to be filtered above the filter layer in the filter to the inlet of the first delivery pump as backwash water after passing through the filter layer.

[0014] Step S3: Backwashing with water. Close the vent valve and start the first delivery pump to send backwash water into the filter through the backwash water inlet pipe. After the backwash water passes through the filter layer in the filter in the reverse direction, it is discharged through the backwash water outlet pipe.

[0015] Preferably, in step S2, the liquid level in the filter is pumped down to below the filter layer by the second delivery pump.

[0016] Preferably, in step S2, the liquid level in the filter is pumped to the bottom position of the filter by the second delivery pump.

[0017] Preferably, the filtration system with backwash water recovery function is further provided with an air inlet pipe, the air outlet of which is connected to the space below the filter layer in the filter; in step S2, the liquid level in the filter is pumped to a position close to the upper surface of the filter layer by the second delivery pump; in step S3, backwash air washing is also included before backwash water washing, the air valve and air inlet pipe are opened, and backwash air is introduced into the filter to perform air washing on the filter layer.

[0018] Preferably, in step S3, after the backwashing air wash has been performed for a preset time, the first delivery pump is started, and backwashing air wash and backwashing water wash are performed simultaneously.

[0019] Preferably, the filtration system with backwash water recovery function is equipped with a liquid level sensor. In step S2, after the liquid level sensor detects that the liquid level of the filter has dropped to a preset position, the liquid level sensor sends a control signal to control the second delivery pump to stop operating.

[0020] The beneficial effects of this invention are that, compared with the prior art, by setting a second delivery pump at the bottom of the filter and a vent valve at the top, and extending the outlet end of the second delivery pump to the inlet end of the first delivery pump, the water to be filtered in the filter can be diverted to the inlet end of the first delivery pump before backwashing begins, through the second delivery pump and the vent valve, so as to be used as subsequent backwash water, thereby realizing the recycling of backwash water, significantly reducing water waste, lowering the operating cost of water treatment, and having good economic benefits and environmental protection effects. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0022] Figure 1 This is a schematic diagram of the structure of a filtration system in the prior art;

[0023] Figure 2 This is a schematic diagram of a filtration system with backwash water recovery function according to an embodiment of the present invention;

[0024] Figure 3This is a schematic diagram of a filtration system with backwash water recovery function in another embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of a filtration system with backwash water recovery function in another embodiment of the present invention;

[0026] Figure 5 To adopt Figure 2 The flowchart of the filtering method of the filtering system in the embodiment shown is illustrated. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] The technical solution provided in this embodiment will be described in detail below with reference to the accompanying drawings.

[0029] Combination Figure 2 As shown, this embodiment discloses a filtration system with backwash water recovery function, including a filter 21, a first delivery pump 22, a second delivery pump 23, and a filter inlet pipe 24, a filter outlet pipe 25, a backwash water inlet pipe 26, and a backwash water outlet pipe 27, all of which are connected to the filter 21.

[0030] A vent valve 28 is provided at the top of the filter 21, which allows the space above the filter layer in the filter 21 to be connected to the outside atmosphere, achieving pressure balance inside and outside the tank. In this embodiment, the filter 21 adopts a filter tank structure, with a quartz sand filter layer inside as the filter media. Of course, in other embodiments, other filter media can be used to form the filter layer, such as glass filter media, garnet filter media, magnetite filter media, activated carbon, etc.

[0031] The inlet of the second pump 23 is connected to the space below the filter layer in the filter 21, and the outlet of the second pump 23 is connected to the inlet of the first pump 22, enabling the filtered water in the filter 21 to be diverted to the inlet of the first pump 22. In this embodiment, both the first pump 22 and the second pump 23 are centrifugal pumps, each with one inlet and one outlet, providing stable water flow power to the system.

[0032] The inlet end of the filter inlet pipe 24 is connected to the outlet end of the first delivery pump 22, the outlet end of the filter inlet pipe 24 is connected to the space above the filter layer in the filter 21, the inlet end of the filter outlet pipe 25 is connected to the space below the filter layer in the filter 21, the inlet end of the backwash water inlet pipe 26 is connected to the outlet end of the first delivery pump 22, the outlet end of the backwash water inlet pipe 26 is connected to the space below the filter layer in the filter 21, and the inlet end of the backwash water outlet pipe 27 is connected to the space above the filter layer in the filter 21.

[0033] In the filtration system of this embodiment, the filter inlet pipe 24, filter outlet pipe 25, backwash water inlet pipe 26, and backwash water outlet pipe 27 all adopt valved pipes, that is, each pipe is equipped with an independently controllable control valve to control the on / off state of the corresponding pipe. By operating the control valve, switching between different functions can be achieved. The control valve can be a manual control valve, an electric control valve, or a pneumatic control valve; it can be an on / off valve or a flow control valve with adjustable flow rate.

[0034] When electric or pneumatic control valves are used, automated control can be achieved. For example, by using a programmable logic controller (PLC) to control the water treatment process in this system, the control valves on the corresponding pipelines can be switched between opening and closing to change the flow path and achieve automated switching control for different water treatment stages.

[0035] During the water treatment process using the filtration system of this embodiment, in the normal water filtration stage, the valves on the filter inlet pipe 24 and the filter outlet pipe 25 are opened, the valves on the backwash water inlet pipe 26 and the backwash water outlet pipe 27 are closed, the first delivery pump 22 is started, the second delivery pump 23 and the vent valve 28 are closed, and the water to be filtered is introduced into the filter 21 through the filter inlet pipe 24, and the filtration process is completed by passing through the filter layer from top to bottom. The filtered water is then transported to the downstream pipe through the filter outlet pipe 25. When backwashing is required after a period of filtration, firstly, open the vent valve 28 and the second transfer pump 23, and close the valves on the first transfer pump 22, the filter inlet pipe 24, the backwash water inlet pipe 26, the filter outlet pipe 25, and the backwash water outlet pipe 27. Through the pumping of the second transfer pump 23, the water to be filtered in the filter 21 is guided to the inlet of the first transfer pump 22 after passing through the filter layer and completing the filtration, so that it can be recycled as backwash water. Then, close the vent valve 28 and the second transfer pump 23, and open the valves on the first transfer pump 22, the backwash water inlet pipe 26, and the backwash water outlet pipe 27. Through the first transfer pump 22, the backwash water is introduced into the lower part of the filter layer in the filter 21, so that the backwash water passes through the filter layer from bottom to top for backwashing. The impurities in the filter layer are discharged with the water through the backwash water outlet pipe 27, thereby completing the backwashing operation.

[0036] In the filtration system of this embodiment, by setting a second delivery pump at the bottom of the filter and a vent valve at the top, and extending the outlet end of the second delivery pump to the inlet end of the first delivery pump, the vent valve can be opened before backwashing begins. The water to be filtered in the filter is then diverted to the inlet end of the first delivery pump through the second delivery pump, and used as backwash water for subsequent backwashing. This achieves backwash water recycling, significantly reduces water waste, lowers the operating cost of water treatment, and has good economic and environmental benefits.

[0037] Combination Figure 2 As shown, in this embodiment, the backwash water outlet pipe 27 is connected to the inlet of the filter 21, so that the inlet of the filter also serves as the backwash outlet. The backwash water inlet pipe 26 is connected to the outlet of the filter 21, so that the outlet of the filter also serves as the backwash inlet. This can further reduce the number of openings and the number of installation pipes on the filter, and optimize the structural design of the filter.

[0038] In addition, such as Figure 2 As shown, in the filtration system of this embodiment, the filter 21 adopts a closed vertical tank structure. Of course, in other embodiments, depending on the space of the usage environment, other forms of closed tank structures may also be adopted, such as a horizontal closed tank.

[0039] Combination Figure 3 As shown, another embodiment also discloses a filtration system with backwash water recovery function, compared to Figure 2 The embodiment shown differs in that the filtration system further includes an air inlet pipe 31. The outlet end of the air inlet pipe 31 is positioned in communication with the space below the filter layer in the filter 21.

[0040] In this embodiment, by setting an air inlet pipe that connects to the space below the filter layer in the filter, flushing air, such as compressed air, can be introduced into the filter during the backwashing process. The flushing air is then used to backwash the filter layer, thereby improving the cleaning effect and efficiency of the filter layer.

[0041] In this embodiment, the air intake pipe 31 also adopts a valved pipe, that is, the pipe is equipped with an independently controllable control valve to control the opening and closing of the pipe. At the same time, the air intake pipe 31 is connected to the water outlet of the filter 21, so that the water outlet on the filter also serves as the backwash air inlet, thereby further reducing the number of openings on the filter and the number of pipes installed, and optimizing the structural design of the filter.

[0042] In other embodiments, the air intake line can be set independently on the filter, that is, an independent air inlet is set on the filter and connected to the air intake line. Especially for horizontal filters, by setting the air intake line independently, the uniformity of the delivered gas can be ensured, and the quality and efficiency of backwashing can be improved.

[0043] Furthermore, combined with Figure 3 As shown, the filtration system in this example also includes a liquid level sensor 32. The liquid level sensor 32 is mounted on the filter 21 and is used to detect changes in the liquid level height within the filter 21. Specifically, this liquid level sensor can be a pressure-type liquid level sensor to accurately acquire liquid level changes.

[0044] In this embodiment, with the air inlet pipe installed, by further installing a liquid level sensor on the filter, the liquid level change can be detected in real time during the process of the second delivery pump drawing out the water to be filtered from above the filter layer before backwashing. When the liquid level drops to near the upper surface of the filter layer, for example, to a position 100mm away from the upper surface of the filter layer, a signal can be sent to stop the second delivery pump, and at the same time, compressed air can be introduced into the air inlet pipe to perform air washing on the filter layer, thereby achieving automated control and improving the convenience and efficiency of operation.

[0045] In other embodiments, depending on the backwashing method, such as directly backwashing the filter layer, the level sensor can send a signal to stop the second delivery pump when the liquid level drops to near the bottom of the filter, thereby completing the water recovery operation before backwashing. This achieves automated control and improves operational convenience and efficiency. Furthermore, in other embodiments, the level sensor can be placed in other locations, such as on the filter outlet pipe, to detect the liquid level in the filter.

[0046] Combination Figure 4 As shown, another embodiment also discloses a filtration system with backwash water recovery function, compared to Figure 2 The embodiment shown differs in that the filtration system further includes a water storage tank 41. The inlet of the water storage tank 41 is connected to the outlet of the second delivery pump 23, and the outlet of the water storage tank 41 is connected to the inlet of the first delivery pump 22. This allows the outlet of the second delivery pump 23 to be connected to the inlet of the first delivery pump 22 via the water storage tank 41, thereby supplying the water pumped by the second delivery pump 23 from the filter 21 to the first delivery pump 22 for recycling in a manner that allows it to be temporarily stored in the water storage tank 41. This meets the needs of different usage scenarios, such as a downstream swimming pool system. Depending on the usage environment, a balance tank or equilibrium tank upstream of the first delivery pump can also be used as the water storage tank. Similarly, referring to the above description, in... Figure 3 In the filtration system shown, the outlet of the second delivery pump 23 can also be connected to the inlet of the first delivery pump 22 through a water storage tank.

[0047] In this embodiment, the water storage tank and the first delivery pump are arranged in parallel, with independent control valves at the inlet and outlet of the water storage tank. The water storage tank also has a vent with a volume not less than the amount of water to be recovered. By controlling the inlet and outlet control valves, precise control can be achieved for the second delivery pump to supply water to the water storage tank and the first delivery pump to draw water from the water storage tank, thus improving the water storage tank's ability to balance and regulate the water supply within the system.

[0048] Combination Figure 5 As shown, this embodiment also discloses a corresponding Figure 2 The filtration method of the filtration system shown specifically includes:

[0049] Step S1, filtration. Start the first delivery pump 22 to send the water to be filtered into the filter 21 through the filter inlet pipe 24, so that the water to be filtered passes through the filter layer in the filter 21 in a forward direction and is discharged through the filter outlet pipe 25.

[0050] Step S2, backwash water recovery. Open the vent valve 28 and start the second transfer pump 23 to transport the water to be filtered above the filter layer in the filter 21 through the filter layer to the inlet of the first transfer pump 22 as backwash water.

[0051] Step S3, backwashing. After the second delivery pump 23 draws the liquid level in the filter 21 down to below the filter layer, close the vent valve 28, start the first delivery pump 22, and send backwash water into the filter 21 through the backwash water inlet pipe 26. The backwash water passes through the filter layer in the filter 21 in the reverse direction and is discharged through the backwash water outlet pipe 27, thereby backwashing and cleaning the filter layer.

[0052] In the backwashing process of the filtration method in this embodiment, the water to be filtered in the filter is first filtered by the second delivery pump and the air valve and then diverted to the inlet of the first delivery pump. This allows the water to be used as backwash water, realizing the recycling of backwash water, reducing the amount of water directly discharged during the backwashing process, significantly reducing water waste, lowering the operating cost of water treatment, and achieving good economic and environmental benefits.

[0053] In step S3 above, the second transfer pump 23 can be used to pump the liquid level in the filter 21 to the bottom of the filter 21. This can significantly reduce the amount of water remaining in the filter when backwash water is introduced, allowing the backwash water entering through the backwash water inlet pipe to enter the filter at a higher speed and perform high-speed backwashing of the filter layer, thereby improving the effect and quality of backwashing.

[0054] Combination Figure 3 As shown, through Figure 3 When the filtration system of the illustrated embodiment performs filtration, it is in conjunction with... Figure 5 The difference in the filtration method shown is that, in the backwash water recovery process of step S2, after the liquid level in the filter 21 is pumped down to a position close to the upper surface of the filter layer by the second transfer pump 23, for example, down to a position 100mm away from the upper surface of the filter layer, backwash air washing is also included before the backwash water washing in step S3, that is, the air valve 28 and the air inlet pipe 31 are opened to introduce compressed air into the filter 21 to perform air washing on the filter layer, thereby improving the cleaning effect and efficiency of the filter layer.

[0055] Furthermore, in step S3, after the backwashing air wash has reached the preset time, the first delivery pump 22 is started to introduce backwash water into the filter 21, simultaneously performing backwashing air washing and backwashing water washing, further improving the cleaning effect and efficiency of the filter layer. Of course, combined with... Figure 3As shown, in the above operation, the liquid level sensor 32 installed on the filter 21 can be used to automatically control the liquid level reduction operation in step S2. For example, after the liquid level drops to the preset position, a signal is automatically sent to stop the second delivery pump 23 and to control the valve on the air inlet pipe 31 to open and introduce compressed air for backwashing, thereby improving the convenience and efficiency of the operation.

[0056] Combination Figure 4 As shown, through Figure 4 When the filtration system of the illustrated embodiment performs filtration, it is in conjunction with... Figure 5 The difference in the filtration method shown is that, in the backwash water recovery process of step S2, the control valve at the outlet of the water storage tank 41 is first closed and the control valve at the inlet of the water storage tank 41 is opened. The water in the filter 21 is pumped to the water storage tank 41 for temporary storage by the second transfer pump 23. Then the water stored in the water storage tank 41 can be used for pumping by the first transfer pump 22.

[0057] The above description is merely a specific embodiment of the present invention. Under the teachings of the present invention, those skilled in the art can make other improvements or modifications based on the above embodiments. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present invention, and the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A filtration system with backwash water recovery function, characterized in that, The system includes a filter, a first delivery pump, a second delivery pump, and filter inlet pipes, filter outlet pipes, backwash water inlet pipes, and backwash water outlet pipes, all connected to the filter. The filter has a vent valve at its top, allowing the space above the filter layer to connect with the outside atmosphere. The inlet of the second delivery pump connects to the space below the filter layer, and the outlet of the second delivery pump connects to the inlet of the first delivery pump. The inlet of the filter inlet pipe connects to the outlet of the first delivery pump, the outlet of the filter inlet pipe connects to the space above the filter layer, the inlet of the filter outlet pipe connects to the space below the filter layer, the inlet of the backwash water inlet pipe connects to the outlet of the first delivery pump, the outlet of the backwash water inlet pipe connects to the space below the filter layer, and the inlet of the backwash water outlet pipe connects to the space above the filter layer.

2. The filtration system with backwash water recovery function according to claim 1, characterized in that, The filtration system is also equipped with an air inlet pipe; the air outlet of the air inlet pipe is connected to the space below the filter layer in the filter.

3. The filtration system with backwash water recovery function according to claim 1, characterized in that, The filtration system is also equipped with a liquid level sensor, which can detect changes in the liquid level in the filter.

4. The filtration system with backwash water recovery function according to claim 1, characterized in that, The filtration system also includes a water storage tank, the inlet of which is connected to the outlet of the second delivery pump, and the outlet of which is connected to the inlet of the first delivery pump.

5. A filtration method with backwash water recovery function, characterized in that, Water filtration is performed using a filtration system with backwash water recovery function as described in any one of claims 1-4, the filtration method comprising: Step S1, Filtration: Start the first delivery pump to send the water to be filtered into the filter through the filter inlet pipe. After the filtered water passes through the filter layer in the filter in the forward direction, it is discharged through the filter outlet pipe. Step S2, backwash water recovery: Open the vent valve, start the second delivery pump, and deliver the water to be filtered above the filter layer in the filter to the inlet of the first delivery pump as backwash water after passing through the filter layer. Step S3: Backwashing with water. Close the vent valve and start the first delivery pump to send backwash water into the filter through the backwash water inlet pipe. After the backwash water passes through the filter layer in the filter in the reverse direction, it is discharged through the backwash water outlet pipe.

6. The filtration method with backwash water recovery function according to claim 5, characterized in that, In step S2, the liquid level in the filter is pumped down to below the filter layer by the second delivery pump.

7. The filtration method with backwash water recovery function according to claim 6, characterized in that, In step S2, the liquid level in the filter is pumped to the bottom position of the filter by the second delivery pump.

8. The filtration method with backwash water recovery function according to claim 5, characterized in that, The filtration system with backwash water recovery function is also provided with an air inlet pipe, the air outlet of which is connected to the space below the filter layer in the filter; in step S2, the liquid level in the filter is pumped to a position close to the upper surface of the filter layer by the second delivery pump; in step S3, backwash air washing is also included before backwash water washing, the air valve and air inlet pipe are opened, and backwash air is introduced into the filter to perform air washing on the filter layer.

9. The filtration method with backwash water recovery function according to claim 8, characterized in that, In step S3, after the backwashing air wash has been performed for a preset time, the first delivery pump is started, and backwashing air wash and backwashing water wash are performed simultaneously.

10. The filtration method with backwash water recovery function according to claim 5, characterized in that, The filtration system with backwash water recovery function is equipped with a liquid level sensor. In step S2, after the liquid level sensor detects that the liquid level of the filter has dropped to a preset position, the liquid level sensor sends a control signal to control the second delivery pump to stop operating.

Images