Sand filter device water-saving backwashing system

Abstract

The application discloses a sand filtering device water-saving forward and reverse washing system, which comprises a sand filtering device, a water storage tank, a forward and reverse washing water supply pipeline and a forward and reverse washing water return pipeline; the sand filtering device is connected with an external cooling circulating water unit through an inlet pipe and an outlet pipe to form a normal filtering circulation loop; the water storage tank is communicated with a drain pipe of the external cooling circulating water unit; the forward and reverse washing water supply pipeline is communicated with the water storage tank and is branched into a forward washing water supply branch communicated with the inlet pipe and a reverse washing water supply branch communicated with the outlet pipe; the forward and reverse washing water return pipeline is communicated with the water storage tank and is branched into a forward washing water return branch communicated with the outlet pipe and a reverse washing water return branch communicated with the inlet pipe; water in the water storage tank realizes forward and reverse washing of the sand filtering device through different water flow paths. The system utilizes the collected cooling circulating water unit drainage to clean the sand filtering device, reduces water resource consumption, simultaneously optimizes the sedimentation and pollution discharge structure and the offline cleaning mode, improves the filtering capacity of the sand filtering device and improves the water resource utilization rate.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, specifically to a water-saving forward and reverse washing system for a sand filter device. Background Technology

[0002] Sand filters, as core equipment for separating insoluble substances in circulating water treatment, effectively remove impurities from water through the contact flocculation, adsorption, and retention effects of their filter media, meeting the system's water quality requirements. They are widely used in cooling circulating water units and have become an indispensable key component. During operation, when the impurities trapped by the sand filter components reach a certain amount, they need to be cleaned through backwashing and forward washing. During cleaning, the impact force of the water flow is used to peel off contaminants from the surface of the filter components, removing the sludge and other deposits trapped during filtration. Wastewater is discharged through a drain valve, thus ensuring the long-term stable operation of the device.

[0003] While existing sand filtration systems are effective in water purification, they suffer from technical deficiencies in water resource utilization. The cooling circulating water unit requires periodic wastewater discharge to control water conductivity. This wastewater is often directly discharged into ditches simply because its conductivity exceeds standards, even though its physical impurity content is consistent with the system's operating water quality. This lack of proper utilization leads to water waste. Furthermore, the sand filter's own forward and reverse washing processes rely on the system's raw water, consuming a large amount of clean water and resulting in low water resource utilization. As industrial production demands increasingly higher water quality, frequent forward and reverse washing operations further exacerbate the water consumption problem. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a water-saving forward and reverse washing system for a sand filter device, which at least solves or alleviates the problems existing in the prior art.

[0005] To achieve the above objectives, a water-saving forward and reverse washing system for a sand filter includes: a sand filter, the upper part of which is connected to an inlet pipe and an internal filter assembly is provided, and the bottom part is connected to an outlet pipe. The inlet pipe and the outlet pipe are respectively connected to the outlet main pipe and the inlet main pipe of an external cooling circulating water unit. A water storage tank, which is connected to the drain pipe of an external cooling water circulation unit, to collect the drainage from the cooling water circulation unit; The forward and reverse washing water supply pipeline has one end connected to the water storage tank, and the other end branches into a forward washing water supply branch connected to the inlet pipe and a reverse washing water supply branch connected to the outlet pipe. The forward and reverse wash return water pipeline has one end connected to the water storage tank, and the other end branches into a forward wash return water branch connected to the outlet water pipe and a reverse wash return water branch connected to the inlet water pipe. During the forward wash, the water in the storage tank enters the sand filter through the forward wash water supply branch and the inlet pipe, and returns through the outlet pipe and the forward wash return water branch. During backwashing, the water in the storage tank enters the sand filter through the forward wash water supply branch and the inlet pipe, and returns through the outlet pipe and the backwash return water branch.

[0006] Optionally, the inlet pipe is connected to the inlet via an inlet valve, and a booster pump is installed at the inlet to allow water to flow through the inlet pipe into the upper part of the sand filter based on the water pressure provided by the booster pump; the outlet pipe is connected to the outlet via an outlet valve, so that the water entering the upper part of the sand filter is filtered by the filter assembly and flows out at the outlet; the outlet and inlet are respectively connected to the inlet main pipe and outlet main pipe of the external cooling circulating water unit to form a circulation loop; Optionally, the forward and reverse wash water supply pipeline is connected to the water storage tank through the forward and reverse wash water pump, the forward wash water supply branch is connected to the inlet pipe through the forward wash water supply valve, and the reverse wash water supply branch is connected to the outlet pipe through the reverse wash water supply valve. The forward wash return water branch is connected to the outlet water pipe through the forward wash return water valve, and the backwash return water branch is connected to the inlet water pipe through the backwash return water valve.

[0007] Optionally, during normal operation, the inlet valve and outlet valve are open, while the backwash return valve, forward wash return valve, backwash supply valve, and forward wash supply valve are closed. When the filter assembly is being forward washed, the forward wash water supply valve and the forward wash return water valve are opened, while the inlet valve, the outlet valve, the backwash water supply valve, and the backwash return water valve are closed. The forward and backwash water pumps drive the water in the storage tank to enter the upper part of the sand filter device through the forward wash water supply branch and the inlet pipe in sequence. After the filter assembly is forward washed, the water flows back to the storage tank through the outlet pipe, the forward wash return water branch, and the forward and backwash return water pipe. When backwashing the filter assembly, the backwash water supply valve and the backwash return water valve are opened, while the inlet valve, the outlet valve, the forward wash water supply valve, and the forward wash return water valve are closed. The forward and reverse wash water pumps drive the water in the storage tank to enter the bottom of the sand filter device through the backwash water supply branch and the outlet pipe in sequence. After backwashing the filter assembly, the water flows back to the storage tank through the inlet pipe, the backwash return water branch, and the forward and reverse wash return water pipes.

[0008] Optionally, the water storage tank is provided with an upper baffle and a lower baffle arranged alternately, as well as a bottom inclined plate at the bottom of the tank, so that impurities in the drainage will settle and accumulate at the bottom of the tank; the bottom of the water storage tank is provided with a drain outlet; an overflow pipe is provided near the drain outlet, and the overflow pipe is used to assist in drainage through the siphon effect.

[0009] Optionally, the upper baffle and the lower baffle are staggered in the water storage tank in a manner that is parallel to each other and perpendicular to the horizontal plane. The upper edge of the upper baffle is flush with the upper edge of the water storage tank, and the lower edge of the lower baffle is connected to the bottom surface of the water storage tank. Both the lower edge of the upper baffle and the upper edge of the lower baffle are submerged in water. The bottom inclined plate is set at a preset angle to the horizontal plane, and its edges are connected to the lower baffle and the bottom surface and side wall of the water storage tank, respectively.

[0010] Optionally, the outlet of the drain pipe of the cooling circulating water unit is located in the area between the upper and lower baffles and above the bottom inclined plate, so as to flush away the sediment impurities on the bottom inclined plate based on the water flow.

[0011] Optionally, the outlet end of the forward and reverse wash return water pipeline is located above the area enclosed by the upper baffle and the side wall of the water storage tank.

[0012] Optionally, the drain outlet is located at the lowest point of the area enclosed by the upper baffle, the side wall of the water storage tank, and the bottom inclined plate. The drain outlet passes through the side wall of the water storage tank via a drain pipe connected to it. A drain valve is provided on the drain pipe to discharge the precipitated impurities.

[0013] Optionally, the overflow pipe passes through the upper side wall of the water storage tank, its water intake is located inside the water storage tank and near the sewage outlet, the water outlet of the overflow pipe extends out of the water storage tank and is connected to the water outlet of the sewage outlet, and the height of the water outlet is lower than the height of the water intake.

[0014] Optionally, it also includes a first check valve and a second check valve; the first check valve is located in the inlet pipe and is close to the outlet of the booster pump, and the second check valve is located in the forward and reverse wash water supply pipeline and is close to the outlet of the forward and reverse wash water pump, so as to prevent cross-flow of water between the cooling circulating water unit and the water storage tank.

[0015] Optionally, the upper part of the side wall of the water storage tank is provided with a tap water float inlet, located in the area enclosed by the lower baffle and the side wall of the water tank. Its height is 10 to 20 cm lower than the height of the overflow pipe passing through the side wall of the water storage tank, and is used to automatically start water replenishment when the water level in the water storage tank is lower than the set value.

[0016] Optionally, the inlet of the forward and reverse washing water supply pipeline is located at the lower part of the side wall of the water storage tank, and within the area enclosed by the lower baffle and the side wall of the water tank.

[0017] Optionally, the capacity of the water storage tank is not less than 10% of the rated flow rate of the sand filter device.

[0018] This technical solution reduces water waste by collecting system drainage through a storage tank connected to the cooling circulating water unit's drain pipe. The staggered arrangement of upper and lower baffles and the inclined plate at the bottom allows impurities in the drainage to settle and accumulate at the bottom of the tank. Combined with the siphon effect of the drain outlet and overflow pipe, this effectively purifies the water. Simultaneously, the layout of the forward and reverse washing water supply and return pipes and corresponding valves allows for forward and reverse washing of the sand filter using water from the storage tank, avoiding the use of the system's raw water and significantly reducing water consumption during the sand filter's forward and reverse washing process. Furthermore, by forming a circulation loop between the sand filter and the cooling circulating water unit, independent offline forward and reverse washing is achieved. This not only fully utilizes the drainage from the cooling circulating water unit, which was originally directly discharged, reducing water consumption, but also increases the filtration capacity and effect of the sand filter by increasing the frequency of forward and reverse washing, further ensuring the stability of the cooling circulating water unit's water quality and improving the overall water resource utilization rate. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of the accompanying drawings are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a water-saving forward and reverse washing system for a sand filter device provided in this embodiment; Figure 2 This is a schematic diagram of the normal operating water flow path of a water-saving forward and reverse washing system for a sand filter device provided in this embodiment; Figure 3 This embodiment provides a schematic diagram of the water flow path in the forward washing mode of a water-saving forward and reverse washing system for a sand filter device. Figure 4 This is a schematic diagram of the water flow path in the backwash mode of a water-saving forward and reverse washing system for a sand filter device provided in this embodiment; In the diagram, the labels represent: 1. Sand filter device; 11. Inlet pipe; 111. Inlet valve; 112. Inlet; 113. Booster pump; 12. Filter assembly; 13. Outlet pipe; 131. Outlet valve; 132. Outlet; 14. First check valve; 2. External cooling circulating water unit; 21. Outlet main pipe; 22. Inlet main pipe; 23. Drain pipe; 231. Outlet end; 3. Water storage tank; 31. Upper baffle; 32. Lower baffle; 33. Bottom inclined plate; 3 4. Sewage outlet; 341. Sewage pipe; 342. Sewage valve; 35. Overflow pipe; 351. Water intake; 36. Float water inlet; 4. Forward and reverse wash water supply pipeline; 41. Forward wash water supply branch; 411. Forward wash water supply valve; 42. Reverse wash water supply branch; 421. Reverse wash water supply valve; 43. Forward and reverse wash water pump; 44. Second check valve; 5. Forward and reverse wash return water pipeline; 51. Forward wash return water branch; 511. Forward wash return water valve; 52. Reverse wash return water branch; 521. Reverse wash return water valve. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the term "comprising" in the specification, claims, and accompanying drawings of this application is intended to cover non-exclusive inclusion. In this application, the terms "upper," "lower," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily used to better describe this application and its embodiments and are not intended to limit the indicated components to having a specific orientation. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0022] Figure 1 This is a schematic diagram of a water-saving forward and reverse washing system for a sand filter according to an embodiment of this application; Figure 2 This is a schematic diagram of the normal operating water flow path of a water-saving forward and reverse washing system for a sand filter device provided in this embodiment; Figure 3 This embodiment provides a schematic diagram of the water flow path in the forward washing mode of a water-saving forward and reverse washing system for a sand filter device. Figure 4 This embodiment provides a schematic diagram of the water flow path in the backwashing mode of a water-saving forward and reverse washing system for a sand filter device; as shown. Figures 1-4As shown, a water-saving forward and reverse washing system for a sand filter device is provided, comprising: a sand filter device 1, wherein an inlet pipe 11 is provided at the upper part of the sand filter device 1, a filter assembly 12 is provided inside, and an outlet pipe 13 is provided at the bottom; the inlet pipe 11 is connected to an inlet 112 through an inlet valve 111, and a booster pump 113 is provided at the inlet 112 to allow water to flow through the inlet pipe 11 into the upper part of the sand filter device 1 based on the water pressure provided by the booster pump 113; the outlet pipe 13 is connected to an outlet 132 through an outlet valve 131, so that the water entering the upper part of the sand filter device 1 is filtered by the filter assembly 12 and flows out at the outlet 132; the outlet 132 and the inlet 112 are respectively connected to the inlet main pipe 22 and the outlet main pipe 21 of an external cooling circulating water unit 2 to form a circulation loop; A water storage tank 3 is connected to the drain pipe 23 of the cooling circulating water unit to collect the drainage of the cooling circulating water unit. The water storage tank 3 is provided with an upper baffle 31 and a lower baffle 32 arranged alternately at the top and bottom, and a bottom inclined plate 33 set at the bottom of the water tank so that impurities in the drainage will settle and accumulate at the bottom of the water tank. A drain outlet 34 is provided at the bottom of the water storage tank 3. An overflow pipe 35 with a water inlet 351 is provided near the drain outlet 34. The overflow pipe 35 is used to assist in drainage through the siphon effect.

[0023] In this embodiment, wastewater that would normally be directly discharged from the system is collected into the water storage tank 3 via the drain pipe 23 connected to the cooling circulating water unit, avoiding waste of high-quality water resources and providing a reliable water source for the forward and reverse washing of the sand filter device 1, reducing dependence on the system's raw water. Secondly, the staggered upper baffle 31 and lower baffle 32 inside form a baffle channel, extending the water flow path. Combined with the inclined plate at the bottom, impurities in the drainage naturally slide down the surface of the inclined plate to the sewage outlet 34 area, achieving efficient sedimentation and separation, and significantly reducing the impurity content entering the sand filter device 1. Furthermore, the overflow pipe 35 with water inlet 351 located near the sewage outlet 34 utilizes the siphon effect to enhance the sewage discharge capacity during the water tank drainage process, automatically discharging impurities settled at the bottom, avoiding secondary suspension of impurities, and ensuring stable water quality in the water storage tank 3. Finally, the combined design of the baffle, inclined plate and overflow pipe 35 not only achieves the synergy of physical sedimentation and dynamic sewage discharge, but also shortens the sedimentation path of impurities through space optimization, improves purification efficiency, provides clean water source for sand filter device 1, extends the service life of filter component 12 and reduces system maintenance costs.

[0024] The forward and reverse wash water supply pipeline 4 has one end connected to the water storage tank 3 via the forward and reverse wash water pump 43, and the other end branches into a forward wash water supply branch 41 and a reverse wash water supply branch 42. The forward wash water supply branch 41 is connected to the inlet pipe 11 via the forward wash water supply valve 411, and the reverse wash water supply branch 42 is connected to the outlet pipe 13 via the reverse wash water supply valve 421. The forward and reverse wash return water pipe 5 is connected to the water storage tank 3 at one end, and branches into the forward wash return water branch 51 and the reverse wash return water branch 52 at the other end. The forward wash return water branch 51 is connected to the outlet water pipe 13 through the forward wash return water valve 511. When the forward wash water supply valve 411 and the forward wash return water valve 511 are open, and the inlet valve 111, the outlet valve 131, the backwash water supply valve 421, and the backwash return water valve 521 are closed, the forward and backwash water pump 43 drives the water in the storage tank 3 to enter the upper part of the sand filter device 1 through the forward wash water supply branch 41 and the inlet water pipe 11 in sequence. After the forward wash filter assembly 12, the water flows back to the storage tank 3 through the outlet water pipe 13, the forward wash return water branch 51, and the forward and backwash return water pipe 5. The backwash return water branch 52 is connected to the inlet pipe 11 through the backwash return water valve 521. When the backwash supply water valve 421 and the backwash return water valve 521 are open, and the inlet valve 111, the outlet valve 131, the forward wash supply water valve 411, and the forward wash return water valve 511 are closed, the forward and reverse wash water pump 43 drives the water in the storage tank 3 to enter the bottom of the sand filter device 1 through the backwash supply water branch 42 and the outlet pipe 13 in sequence. After backwashing the filter assembly 12, the water flows back to the storage tank 3 through the inlet pipe 11, the backwash return water branch 52, and the forward and reverse wash return water pipeline 5.

[0025] In this embodiment, the forward and reverse wash water supply pipeline 4 and the return water pipeline are respectively connected to the water storage tank 3. Combined with the forward and reverse wash water pump 43, the corresponding forward wash water supply valve 411, forward wash return water valve 511, reverse wash water supply valve 421, and reverse wash return water valve 521, a cleaning circuit independent of the main cooling water circulation system is formed. The opening and closing combination of the valves realizes the flexible switching between normal circulation filtration and forward and reverse washing.

[0026] During normal circulation filtration, the inlet valve 111 and outlet valve 131 are open, while the backwash return valve 521, forward wash return valve 511, backwash supply valve 421, and forward wash supply valve 411 are closed. At this time, the booster pump 113 pressurizes the water from the outlet main pipe 21 of the external cooling circulating water unit 2 and delivers it to the upper part of the sand filter device 1 through the inlet 112 and inlet pipe 11. The water flows from top to bottom through the internal filter assembly 12. Under the flocculation, adsorption, and interception effects of the filter assembly 12, insoluble substances in the water are removed. The purified water flows out from the outlet pipe 13 at the bottom of the sand filter device 1 and returns to the inlet main pipe 22 of the cooling circulating water unit through the outlet 132, thus forming a complete circulation loop to achieve continuous filtration and purification of the cooling circulating water and ensure that the system water quality meets the operating requirements. During forward washing, the forward washing water supply valve 411 and forward washing return water valve 511 are opened, while the inlet valve 111, outlet valve 131, backwash water supply valve 421, and backwash return water valve 521 are closed. The forward and backwash water pump 43 drives the water in the storage tank 3 to enter the upper part of the sand filter device 1 through the forward washing water supply branch 41 and the inlet pipe 11, rinsing the filter assembly 12 from top to bottom. Wastewater flows back to the storage tank 3 through the outlet pipe 13 and the forward washing return water branch 51. During backwashing, the backwash water supply valve 421 and backwash return water valve 521 are opened, while the other related valves are closed. The water in the storage tank 3 enters the bottom of the sand filter device 1 through the backwash water supply branch 42 and the outlet pipe 13, forcefully flushing the filter assembly 12 from bottom to top, removing deep impurities, and then flows back through the inlet pipe 11 and the backwash return water branch 52. This design not only utilizes system drainage to replace raw water for cleaning, significantly reducing water consumption, but also avoids interference with the main system's operation through an offline cleaning mode independent of the main cooling circulating water system. Furthermore, thanks to a stable cleaning water source and flexible cleaning modes, the system can appropriately increase the frequency of forward and reverse washing, thereby improving the filtration capacity and effect of the sand filter device 1, ultimately achieving a dual improvement in water resource utilization and water quality stability.

[0027] Optionally, the upper baffle 31 and the lower baffle 32 are staggered in the water storage tank 3 in a manner that is parallel to each other and perpendicular to the horizontal plane. The upper edge of the upper baffle 31 is flush with the upper edge of the water storage tank 3, and the lower edge of the lower baffle 32 is connected to the bottom surface of the water storage tank 3. The lower edges of the upper baffle 31 and the upper edges of the lower baffle 32 are submerged in water. The bottom inclined plate 33 is set at a preset angle to the horizontal plane, and its edges are connected to the lower baffle 32 and the bottom surface and side wall of the water storage tank 3, respectively.

[0028] In this embodiment, the upper baffle 31 and the lower baffle 32 in the water storage tank 3 are staggered in a way that is parallel to each other and perpendicular to the horizontal plane. The upper edge of the upper baffle 31 is flush with the upper edge of the water storage tank 3, and the lower edge of the lower baffle 32 is connected to the bottom of the tank. Both the lower and upper edges of the two are submerged in water. Together with the bottom inclined plate 33 which is inclined at a preset angle to the horizontal plane, the edge is connected to the lower baffle 32, the bottom of the tank and the side wall, forming a multi-level sedimentation and purification structure. First, the staggered vertical baffle design creates a flow-deflecting channel within the water storage tank 3, forcing the water flow to meander and prolonging the sedimentation time of impurities. Simultaneously, the inertia of the water flow causes particulate impurities to collide with the baffles, accelerating their settling. Second, the layout of the upper baffle 31 flush with the tank edge and the lower baffle 32 touching the bottom ensures that the water flow is deflected throughout the tank, guaranteeing the stability of the sedimentation process. Third, the inclined angle of the bottom plate 33 causes settled impurities to slide and accumulate along the plate surface towards the drain outlet 34, shortening the sedimentation path and improving discharge efficiency. Its connection with the lower baffle 32, the bottom of the tank and the side wall forms a closed sedimentation area, which further enhances the directional aggregation effect of impurities. In addition, this structure can achieve efficient separation of impurities without additional power, which not only reduces system energy consumption, but also optimizes the water flow path and sedimentation space, so that the water storage tank 3 can achieve the best water purification effect within a limited volume, providing a clean cleaning water source for the sand filter device 1, thereby reducing maintenance costs caused by impurities clogging the filter components 12, and finally achieving the dual benefits of water resource recycling and stable system operation.

[0029] Optionally, the outlet end 231 of the drain pipe 23 of the cooling circulating water unit is located in the area between the upper and lower baffles 32 and above the bottom inclined plate 33, so as to flush away the sediment impurities on the bottom inclined plate 33 based on the water flow.

[0030] In this embodiment, the outlet end 231 of the drain pipe 23 of the cooling circulating water unit is located in the area between the upper and lower baffles 32 of the water storage tank 3, and is located above the bottom inclined plate 33. This layout design has significant technical advantages. On the one hand, since the outlet 231 of the drain pipe 23 is located between the upper and lower baffles 32, when the water flows into the water storage tank 3, it can naturally meander in the baffle-formed flow channel, further extending the sedimentation time of impurities and improving the sedimentation effect. On the other hand, the water outlet is located above the bottom inclined plate 33, so that the drainage of the cooling circulating water unit can directly flush the impurities that have settled on the bottom inclined plate 33 after entering the water storage tank 3. With the help of the kinetic energy of the water flow, the impurities attached to the inclined plate are flushed up and moved with the water flow, and finally discharged through the drain outlet 34 or overflow pipe 35, avoiding the accumulation of impurities on the inclined plate and affecting the sedimentation efficiency. In addition, this design does not require additional stirring or rinsing equipment, and cleverly uses the kinetic energy of the drainage itself to achieve self-cleaning of the inclined plate, reducing system energy consumption and maintenance costs. At the same time, the stable water flow helps to keep the water quality in the water storage tank 3 clean.

[0031] Optionally, the outlet end of the forward and reverse wash return water pipeline 5 is located above the area enclosed by the upper baffle 31 and the side wall of the water storage tank 3.

[0032] Optionally, the drain outlet 34 is located at the lowest point of the area enclosed by the upper baffle 31, the side wall of the water storage tank 3, and the bottom inclined plate 33. The drain outlet 34 passes through the side wall of the water storage tank 3 via a drain pipe 341 connected to it. A drain valve 342 is provided on the drain pipe 341 to discharge the precipitated impurities.

[0033] In this embodiment, the drain outlet 34 is located at the lowest point of the area enclosed by the upper baffle 31, the side wall of the water tank 3, and the bottom inclined plate 33. It is connected to the drain valve 342 via a drain pipe 341 that passes through the side wall of the water tank 3. This design offers significant advantages in impurity handling and system maintenance. First, the drain outlet 34 is located at the lowest point of the area. Utilizing gravity, impurities deposited on the bottom inclined plate 33 can naturally converge there, achieving efficient collection without additional power and effectively reducing system energy consumption. Second, the combination of the drain pipe 341 and the drain valve 342 allows operators to flexibly control the timing and volume of drainage according to actual needs. When impurities in the water tank 3 settle to a certain extent, simply opening the drain valve 342 quickly removes the deposited impurities, preventing their accumulation from affecting the water quality of the water tank 3. Furthermore, this layout makes the drainage path direct and smooth, reducing the risk of impurities clogging the pipes during drainage and lowering maintenance frequency and costs. Finally, timely removal of deposited impurities ensures that the water stored in the water tank 3 remains clean.

[0034] Optionally, the overflow pipe 35 passes through the upper side wall of the water storage tank 3, and its water intake 351 is located inside the water storage tank 3 and near the sewage outlet 34. The water outlet 231 of the overflow pipe 35 extends out of the water storage tank 3 and is connected to the water outlet 231 of the sewage outlet 34. The height of the water outlet 231 is lower than the height of the water intake 351.

[0035] In this embodiment, the overflow pipe 35 is designed to pass through the upper side wall of the water storage tank 3, with the water inlet 351 near the sewage outlet 34 and the water outlet 231 lower than the water inlet 351. Through the ingenious siphon principle and structural layout, multiple technical advantages are achieved. First, the water inlet 351 is positioned close to the drain outlet 34, allowing the overflow pipe 35 to prioritize drawing water containing more sediment and impurities from the area near the bottom inclined plate 33 when the water level in the storage tank 3 rises. The siphon effect of the water flow effectively removes impurities deposited in the drain outlet 34 area, enhancing the self-cleaning capability of the storage tank 3. Second, the height difference between the outlet 231 and the water inlet 351 ensures that the overflow pipe 35 automatically activates the siphon effect when the water level reaches a certain height, continuously discharging impurities without additional power, thus reducing system energy consumption. Third, the connection between the overflow pipe 35 and the outlet 231 of the drain outlet 34 not only optimizes the drainage path but also creates a synergistic effect during drainage, further improving impurity discharge efficiency and reducing the frequency of manual cleaning. Furthermore, this design avoids water quality deterioration caused by long-term impurity accumulation, ensuring the cleanliness of the water in the storage tank 3 and providing a stable and high-quality cleaning water source for the sand filter device 1.

[0036] Optionally, it also includes a first check valve 14 and a second check valve 44; the first check valve 14 is located in the water inlet pipe 11 and is close to the water outlet 231 of the booster water pump 113, and the second check valve 44 is located in the forward and reverse wash water supply pipeline 4 and is close to the water outlet 231 of the forward and reverse wash water pump 43, so as to prevent water flow from mixing between the cooling circulating water unit and the water storage tank 3.

[0037] In this embodiment, the first check valve 14 and the second check valve 44 added to the system are respectively located near the outlet 231 of the booster water pump 113 and the forward and reverse wash water pump 43, providing a reliable guarantee for the stable operation of the system and the efficient use of water resources. First, the first check valve 14 is installed near the outlet 231 of the booster water pump 113 and the inlet pipe 11, ensuring that the water flow of the cooling circulating water unit can only flow into the sand filter device 1 in one direction, effectively preventing backflow of water in the main system and ensuring the normal pressure and flow stability of the cooling circulating water system. Second, the second check valve 44 is located near the outlet 231 of the forward and reverse wash water supply pipeline 4 and the forward and reverse wash water pump 43, preventing the water in the storage tank 3 from flowing back to the pump during the forward and reverse wash process, avoiding the waste of cleaning water and the risk of contaminating the water quality of the main system. Furthermore, the synergistic effect of the two check valves This design fundamentally eliminates the problem of water flow crosstalk between the cooling circulating water unit and the water storage tank 3, preventing water loss in the main system due to crosstalk and ensuring the cleanliness of the cleaning water in the water storage tank 3. In addition, the installation of the one-way valve does not require complex control procedures; precise control of the water flow direction is achieved through mechanical structure, reducing the risk of system malfunction and maintenance costs. Ultimately, this design ensures that the sand filter device 1 can operate stably in both normal filtration and forward / reverse washing modes, significantly improving the safety and reliability of the entire water-saving forward / reverse washing system, thereby improving the efficiency of water resource utilization.

[0038] Optionally, the upper part of the side wall of the water storage tank 3 is provided with a tap water float inlet 36, located in the area enclosed by the lower baffle 32 and the side wall of the water tank. Its height is 10 to 20 cm lower than the height of the overflow pipe 35 passing through the side wall of the water storage tank 3, and is used to automatically open the water supply when the water level of the water storage tank 3 is lower than the set value.

[0039] In this embodiment, a tap water float inlet 36 is installed on the upper part of the side wall of the water storage tank 3, and it is placed in the area enclosed by the lower baffle 32 and the side wall of the water tank. Simultaneously, the height of this inlet is 10 to 20 cm lower than the height of the overflow pipe 35 passing through the side wall of the water storage tank 3. This design ensures stable system operation and rational water resource utilization from multiple dimensions. First, placing the inlet in the area enclosed by the lower baffle 32 and the side wall ensures that the replenished tap water will not directly impact the impurities already settled on the bottom inclined plate 33, avoiding secondary suspension and ensuring the cleanliness of the water in the water storage tank 3. Second, the 10 to 20 cm height difference between the tap water float inlet 36 and the overflow pipe 35 allows for automatic water replenishment via a float linkage mechanism when the water level in the water storage tank 3 drops to a set threshold, without manual intervention. This ensures that the water storage tank 3 always maintains a sufficient water volume, guaranteeing a continuous and stable water supply during the forward and reverse washing processes of the sand filter device 1. Water; in addition, the design provides dual protection for emergency water replenishment and overflow prevention. When the manual sewage discharge is large or the cooling circulating water unit is insufficient, the water inlet replenishes water in time, while the overflow pipe 35 can prevent the water level from overflowing due to excessive water level, thus avoiding water waste. Finally, through this intelligent and stable water replenishment structure, not only is the reliability of system operation improved and the risk of sand filter device 1 cleaning interruption caused by water shortage reduced, but the water resource allocation capacity of the entire water-saving forward and reverse washing system is further optimized, ultimately achieving the dual benefits of efficient water resource utilization and stable system operation.

[0040] Optionally, the inlet of the forward and reverse washing water supply pipeline 4 is located at the lower part of the side wall of the water storage tank 3, and within the area enclosed by the lower baffle 32 and the side wall of the water tank.

[0041] In this embodiment, the inlet of the forward and reverse washing water supply pipeline 4 is located at the lower part of the side wall of the water storage tank 3 and within the area enclosed by the lower baffle 32 and the side wall of the water tank. This design improves the system performance and water resource utilization efficiency from multiple levels. On the one hand, placing the water inlet in the area enclosed by the lower baffle 32 and the side wall effectively avoids drawing water from the upper part of the water storage tank 3, where there may be suspended impurities. This ensures that the water entering the forward and reverse washing water supply pipeline 4 is clean, providing high-quality cleaning water for the sand filter device 1, thereby improving the filtration effect and service life of the sand filter device 1. On the other hand, since this area is located at a lower position in the water storage tank 3, gravity allows the water to naturally converge, facilitating more efficient water extraction by the forward and reverse washing water pump 43, reducing pump energy consumption, and improving water extraction efficiency. In addition, this layout keeps the water inlet away from the water inlet area of ​​the cooling circulating water unit drain pipe 23, avoiding interference from newly entering water storage tank 3 drainage on the water extraction process, and preventing sedimentation impurities from affecting the water quality due to water flow disturbance. Finally, this structural design, combined with the sedimentation and purification mechanism inside the water storage tank 3, further ensures the stability and cleanliness of the water source during the forward and reverse washing process, ensuring that the sand filter device 1 can maintain efficient and stable operation in water-saving mode, achieving the recycling of water resources and synergistic optimization of system performance.

[0042] Optionally, the capacity of the water storage tank 3 is not less than 10% of the rated flow rate of the sand filter device 1.

[0043] In this embodiment, the capacity of the water storage tank 3 is designed to be no less than 10% of the rated flow of the sand filter device 1. This parameter setting plays a key role in ensuring the stable operation of the system and improving the efficiency of water resource utilization. First, this capacity standard ensures that the water storage tank 3 can store sufficient drainage from the cooling circulating water unit to meet the water demand of multiple forward and reverse washing cycles of the sand filter device 1, avoiding cleaning interruptions due to insufficient water and thus ensuring the continuous and efficient operation of the sand filter device 1. Second, the ample water storage provides a buffer for the system to cope with drainage fluctuations. Even if the drainage volume of the cooling circulating water unit decreases in the short term, the water storage tank 3 can maintain a stable water supply, ensuring the continuity of the cleaning process. Third, the reasonable capacity setting effectively reduces energy consumption and management costs caused by frequent water replenishment while avoiding water waste. In addition, the water storage tank 3 that meets this capacity requirement can match the operating rhythm of the sand filter device 1, making the water supply stable during forward and reverse washing, improving the cleaning effect, and thus extending the service life of the filter components 12 of the sand filter device 1. Finally, this capacity design achieves an organic balance between water storage, water supply, and water conservation, enhancing the reliability and practicality of the entire sand filter device's water-saving forward and reverse washing system.

[0044] Optionally, the inlet valve 111, outlet valve 131, backwash return valve 521, forward wash return valve 511, backwash supply valve 421, and forward wash supply valve 411 are controllable valves to facilitate automated control.

[0045] Optionally, it also includes a control system, which is electrically connected to the electric valve and is used to control the opening and closing of the valve according to a set mode switching sequence. The mode switching sequence is normal mode → backwash mode, lasting 5 minutes → forward wash mode, lasting 2 minutes → normal mode. During all valve switching processes, the principle of closing before opening is followed.

[0046] In this embodiment, the linkage design of the control system and the electric valve, combined with the preset mode switching sequence and the "close first, then open" principle, improves the operational efficiency of the water-saving forward and reverse washing system of the sand filter device from multiple dimensions. First, by setting a fixed process of "normal mode → backwash mode (5 min) → forward washing mode (2 min) → normal mode," the system can achieve automated cyclic operation. Compared with manual operation, this not only avoids problems such as inaccurate control of cleaning time and chaotic process connections, but also ensures that the sand filter device 1 is regularly and efficiently cleaned, continuously maintaining good filtration performance. Second, the 5-minute backwashing stage utilizes the water in the storage tank 3 to powerfully flush the filter component 12 from bottom to top, effectively removing deeply trapped pollutants. The subsequent 2-minute forward washing process rinses residual impurities on the surface of the filter component 12 from top to bottom. The two processes complement each other, forming a scientific and efficient cleaning combination, significantly improving the water-saving forward and reverse washing system. This design significantly improves cleaning efficiency. Furthermore, the "close first, open later" valve switching principle prevents cross-contamination between the cooling water main system and the forward and reverse washing circuits during mode switching. This ensures stable main system pressure and prevents wastewater from contaminating the raw water, guaranteeing the cleanliness of the water in storage tank 3 and providing a reliable guarantee for subsequent cleaning. In addition, the automated control system greatly reduces the need for manual intervention, minimizing labor costs and the risk of operational errors. It can also achieve long-term unattended operation through preset programs. Ultimately, this design, through intelligent and standardized mode switching and valve control, achieves comprehensive optimization of system stability, cleaning efficiency, water resource utilization efficiency, and safety.

[0047] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A water-saving forward and reverse washing system for a sand filter device, characterized in that, include: The sand filter device (1) is connected to the inlet pipe (11) at its upper part and is equipped with a filter assembly (12) inside. The bottom is connected to the outlet pipe (13). The inlet pipe (11) and the outlet pipe (13) are respectively connected to the outlet main pipe (21) and the inlet main pipe (22) of the external cooling circulating water unit (2). A water storage tank (3) is connected to the drain pipe (23) of the external cooling water circulation unit (2) to collect the drainage of the cooling water circulation unit; The forward and reverse washing water supply pipeline (4) has one end connected to the water storage tank (3) and the other end branched into a forward washing water supply branch (41) connected to the inlet pipe (11) and a reverse washing water supply branch (42) connected to the outlet pipe (13). The forward and reverse wash return water pipeline (5) has one end connected to the water storage tank (3) and the other end branched into a forward wash return water branch (51) connected to the water outlet pipe (13) and a reverse wash return water branch (52) connected to the water inlet pipe (11). During the washing process, the water in the storage tank (3) enters the sand filter device (1) through the washing water supply branch (41) and the inlet pipe (11), and returns through the outlet pipe (13) and the washing return water branch (51). During backwashing, the water in the storage tank (3) enters the sand filter device (1) through the forward wash water supply branch (41) and the inlet pipe (11), and returns through the outlet pipe (13) and the backwash return water branch (52).

2. The water-saving forward and reverse washing system of the sand filter device according to claim 1, characterized in that, The inlet pipe (11) is connected to the inlet (112) through the inlet valve (111). A booster pump (113) is provided at the inlet (112) so that water flows through the inlet pipe (11) into the upper part of the sand filter device (1) based on the water pressure provided by the booster pump (113). The outlet pipe (13) is connected to the outlet (132) through the outlet valve (131) so that the water entering the upper part of the sand filter device (1) is filtered by the filter assembly (12) and flows out at the outlet (132). The outlet (132) and the inlet (112) are respectively connected to the inlet main pipe (22) and the outlet main pipe (21) of the external cooling circulating water unit (2) to form a circulation loop.

3. The water-saving forward and reverse washing system of the sand filter device according to claim 2, characterized in that, The forward and reverse wash water supply pipeline (4) is connected to the water storage tank (3) through the forward and reverse wash water pump (43), the forward wash water supply branch (41) is connected to the inlet pipe (11) through the forward wash water supply valve (411), and the reverse wash water supply branch (42) is connected to the outlet pipe (13) through the reverse wash water supply valve (421). The forward wash return water branch (51) is connected to the outlet pipe (13) through the forward wash return water valve (511), and the backwash return water branch (52) is connected to the inlet pipe (11) through the backwash return water valve (521).

4. The water-saving forward and reverse washing system of the sand filter device according to claim 3, characterized in that, During normal operation, the inlet valve (111) and outlet valve (131) are open, while the backwash return valve (521), forward wash return valve (511), backwash supply valve (421), and forward wash supply valve (411) are closed. When the filter assembly (12) is being forward washed, the forward wash water supply valve (411) and the forward wash return water valve (511) are opened, and the inlet valve (111), outlet valve (131), backwash water supply valve (421), and backwash return water valve (521) are closed. The forward and backwash water pump (43) drives the water in the storage tank (3) to enter the upper part of the sand filter device (1) through the forward wash water supply branch (41) and the inlet pipe (11) in sequence. After the filter assembly (12) is forward washed, the water flows back to the storage tank (3) through the outlet pipe (13), the forward wash return water branch (51), and the forward and backwash return water pipeline (5). When backwashing the filter assembly (12), the backwash water supply valve (421) and the backwash return water valve (521) are opened, and the inlet valve (111), the outlet valve (131), the forward wash water supply valve (411), and the forward wash return water valve (511) are closed. The forward and reverse wash water pump (43) drives the water in the storage tank (3) to enter the bottom of the sand filter device (1) through the backwash water supply branch (42) and the outlet pipe (13) in sequence. After backwashing the filter assembly (12), the water flows back to the storage tank (3) through the inlet pipe (11), the backwash return water branch (52), and the forward and reverse wash return water pipe (5).

5. The water-saving forward and reverse washing system of the sand filter device according to claim 4, characterized in that, The water storage tank (3) is provided with an upper baffle (31) and a lower baffle (32) arranged alternately, and a bottom inclined plate (33) set at the bottom of the water tank, so that impurities in the drainage will settle and gather at the bottom of the water tank; the bottom of the water storage tank (3) is provided with a drain outlet (34); a water intake (351) of an overflow pipe (35) is provided near the drain outlet (34), and the overflow pipe (35) is used to assist in the drainage through the siphon effect.

6. The water-saving forward and reverse washing system of the sand filter device according to claim 5, characterized in that, The upper baffle (31) and the lower baffle (32) are staggered in the water tank (3) in a way that they are parallel to each other and perpendicular to the horizontal plane. The upper edge of the upper baffle (31) is flush with the upper edge of the water tank (3), and the lower edge of the lower baffle (32) is connected to the bottom surface of the water tank (3). The lower edge of the upper baffle (31) and the upper edge of the lower baffle (32) are both submerged in water. The bottom inclined plate (33) is set at a preset angle to the horizontal plane, and its edge is connected to the lower baffle (32), the bottom surface of the water tank (3), and the side wall of the water tank (3) respectively.

7. The water-saving forward and reverse washing system of the sand filter device according to claim 6, characterized in that, The outlet end (231) of the drain pipe (23) of the cooling circulating water unit is located in the area between the upper and lower baffles (32) and above the bottom inclined plate (33) to flush away sediment impurities on the bottom inclined plate (33) based on the water flow.

8. The water-saving forward and reverse washing system of the sand filter device according to claim 6, characterized in that, The drain outlet (34) is located at the lowest point of the area enclosed by the upper baffle (31), the side wall of the water tank (3) and the bottom inclined plate (33). The drain outlet (34) passes through the side wall of the water tank (3) through the drain pipe (341) connected to it. The drain pipe (341) is equipped with a drain valve (342) to discharge the sedimented impurities.

9. The water-saving forward and reverse washing system of the sand filter device according to claim 8, characterized in that, The overflow pipe (35) passes through the upper side of the side wall of the water storage tank (3), and its water intake (351) is located inside the water storage tank (3) and near the sewage outlet (34). The water outlet (231) of the overflow pipe (35) extends out of the water storage tank (3) and is connected to the water outlet (231) of the sewage outlet (34). The height of the water outlet (231) is lower than the height of the water intake (351).

10. The water-saving forward and reverse washing system of the sand filter device according to claim 9, characterized in that, It also includes a first check valve (14) and a second check valve (44); the first check valve (14) is located in the inlet pipe (11) and is close to the outlet (231) of the booster water pump (113), and the second check valve (44) is located in the forward and reverse wash water supply pipeline (4) and is close to the outlet (231) of the forward and reverse wash water pump (43) to prevent water flow from mixing between the cooling circulating water unit and the water storage tank (3).

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