A low-temperature multi-effect seawater desalination system automatic backwashing filter device and backwashing method thereof

Abstract

The present invention relates to the field of seawater desalination technology, and in particular to an automatic backwashing filter device for a low-temperature multi-effect seawater desalination system, comprising a first filter and a second filter, characterized in that: the first filter and the second filter are interconnected through a pipeline, a first sewage discharge control valve and a second sewage discharge control valve are connected to the lower ends of the first filter and the second filter respectively, a filter cartridge is disposed inside the first filter and the second filter, an upper fixed baffle of the filter cartridge is fixedly connected to the upper end of the filter cartridge, a lower fixed baffle of the filter cartridge is fixedly connected to the lower end of the filter cartridge, and an upper variable pitch impeller is installed on the inner side of the upper fixed baffle of the filter cartridge. After the implementation of the present invention, the safe and stable operation of the seawater desalination device can be effectively guaranteed, and the frequency of nozzle disassembly and cleaning can be reduced. The present invention has the advantages of flexible operation, stable performance, high efficiency, short downtime, low maintenance cost and significant effect.

Description

Technical Field

[0001] The invention relates to the technical field of seawater desalination, and in particular to an automatic backwashing filter device of a low-temperature multi-effect seawater desalination system and a backwashing method thereof. Background Art

[0002] At present, the low-temperature multi-effect seawater desalination device refers to the desalination technology with the highest evaporation temperature of the original seawater below 70℃. It is characterized by connecting a series of evaporators containing spray tube bundles in series, using a certain amount of steam input, and evaporating and condensing multiple times. The evaporation temperature of the latter effect is lower than that of the previous effect. After multiple evaporations and condensations, desalinated water with multiple times the amount of steam is obtained. In the heat exchange process of low-temperature multi-effect seawater desalination, the original seawater or concentrated seawater is evenly distributed on the outer surface of the heat exchange tube bundle of each evaporator through the nozzle through the feeding system in a thin film distribution, flowing from top to bottom. Part of the seawater absorbs the latent heat of the condensed steam in the heat exchange tube and vaporizes. The remaining concentrated seawater is pumped into the next effect group of the evaporator through the feeding pump. The above process is repeated to realize the desalinated water production process.

[0003] Since the low-temperature multi-effect seawater desalination system has a relatively low requirement for the turbidity of the effluent from the seawater pretreatment (generally not higher than 15NTU), with the long-term use of the seawater pretreatment system, part of the sediment is deposited in the coagulation sedimentation tank and the clear water tank and enters the feeding system and spraying system of the seawater desalination device; in addition, due to the corrosion and shedding of the anti-corrosion coating inside the evaporator of the seawater desalination system, these flaky particles are mixed with the remaining sediment entering the seawater desalination device. At the beginning of the design of the seawater desalination system, a basket filter was used, and the filter screen was not provided with a sewage flow channel. During operation, it is very easy for particulate matter to block the mesh holes at a local position, causing the concentrated seawater flow rate to slow down, resulting in the accumulation of mixed sediment inside the filter screen, causing the filter inlet and outlet pressure difference to increase, the flow rate to decrease, affecting the water production ratio of the seawater desalination device, and causing nozzle blockage, which leads to uneven water distribution, spray pipe rupture, reduced contact area between steam (heat source) and water (cold source), reduced heat exchange efficiency, and scaling of the heat exchange tube.

[0004] The current cleaning method is only to manually remove the upper end cover of the filter, take out the filter screen for external cleaning, and the implementation process is relatively complicated, especially during the operation of the seawater desalination device, the filter screen cleaning operation process poses a great hidden danger to the continuous, safe and stable operation of the equipment. The implementation process is difficult, time-consuming, labor-intensive, and has high labor costs. There are great construction safety risks and many uncontrollable factors, so the effect of using manual mechanical cleaning methods is not ideal.

[0005] Therefore, there is a need for an automatic backwashing filter device and a backwashing method for a low-temperature multi-effect seawater desalination system that can solve the above problems. Summary of the invention

[0006] The present invention mainly aims at the problems that the impurities such as shellfish, lacquer, mud and sand mixed in the raw seawater and concentrated seawater of each level in the feeding system of the low-temperature multi-effect seawater desalination device block the nozzles, resulting in uneven water distribution, broken spray pipes, reduced steam-water contact area, reduced heat exchange efficiency, scaling of heat exchange tubes, etc. An automatic backwashing filter device and backwashing method for a low-temperature multi-effect seawater desalination system are proposed. After implementation, the safe and stable operation of the seawater desalination device can be effectively guaranteed, and the frequency of nozzle disassembly and cleaning can be reduced. The present invention has the advantages of flexible operation, stable performance, high efficiency, short downtime, low maintenance cost and significant effect.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: an automatic backwash filtration device for a low-temperature multi-effect seawater desalination system, comprising a first filter and a second filter, the first filter and the second filter being connected to each other through a pipeline, a first sewage discharge control valve and a second sewage discharge control valve being connected to the lower ends of the first filter and the second filter respectively, a filter cartridge is arranged inside the first filter and the second filter, an upper fixed baffle of the filter cartridge is fixedly connected to the upper end of the filter cartridge, a lower fixed baffle of the filter cartridge is fixedly connected to the lower end of the filter cartridge, an upper variable pitch impeller is installed on the inner side of the upper fixed baffle of the filter cartridge, a lower variable pitch impeller is installed on the outer side of the lower fixed baffle of the filter cartridge, a swirl guide rod is arranged inside the filter cartridge, and a plurality of swirl blades are installed on the swirl guide rod.

[0008] Furthermore, the first filter and the second filter each have an inlet end and an outlet end, and a first water inlet control valve and a second water inlet control valve are respectively installed on the inlet ends of the first filter and the second filter, and a first water outlet control valve and a second water outlet control valve are respectively installed on the outlet ends of the first filter and the second filter.

[0009] Further, a first inlet pressure transmitter is installed on the inlet end of the first filter, a first outlet pressure transmitter is installed on the outlet end of the first filter, a second inlet pressure transmitter is installed on the inlet end of the second filter, and a second outlet pressure transmitter is installed on the outlet end of the second filter.

[0010] Furthermore, the filter cartridge is a columnar filter screen that is transparent from top to bottom, and a plurality of reinforcing ribs are arranged inside the filter screen.

[0011] Furthermore, an aeration disturbance cylinder is arranged outside the filter cartridge, and the internal structure of the aeration disturbance cylinder is a hollow pore screen, which is used to distribute the impact effect generated by the compressed gas explosion process to remove stubborn impurity particles attached to the filter cartridge.

[0012] Furthermore, a thrust bearing is installed inside the filter cartridge, and the upper variable pitch impeller and the lower variable pitch impeller are coaxially connected to the upper and lower ends of the thrust bearing.

[0013] Furthermore, a circulation reflux pump is installed on one side of the filter cartridge, and the circulation reflux pump is used to push the upper variable pitch blades.

[0014] Furthermore, the tops of the first filter and the second filter are both connected to exhaust control valves.

[0015] Furthermore, one side of each of the first filter and the second filter is connected to a circulation thrust pump, and the circulation thrust pump is used to push the swirl blades provided on the swirl guide rod.

[0016] A backwashing method for an automatic backwashing filter device of a low-temperature multi-effect seawater desalination system, characterized in that it comprises the following steps:

[0017] S1: First, the first filter and the second filter are operated simultaneously. At this time, the first water inlet control valve, the second water inlet control valve, the first water outlet control valve, and the second water outlet control valve are all in the open state, and the first sewage control valve and the second sewage control valve are in the closed state. The original seawater or concentrated seawater flows in through the inlet ends of the first filter and the second filter respectively, and flows out from the outlet ends of the first filter and the second filter.

[0018] S2: The operating load is high, and the filter performs the backwashing process in the following operating states: the first filter operates normally and the second filter operates in the backwashing state. At this time, the first water inlet control valve, the second water inlet control valve, the first water outlet control valve, and the second water outlet control valve are all in the open state, and the second sewage control valve is in the open state. At this time, the control system is adjusted:

[0019] (1) The up and down variable pitch impeller adjusts the blade direction to be perpendicular to the water flow to form the maximum thrust to drive the filter cartridge drive shaft and the filter cartridge cleaning brush;

[0020] (2) The circulating thrust pump pushes the swirl blades on the swirl guide rod, and then transmits the rotational power to the filter cartridge drive shaft and the filter cartridge cleaning brush through the forward drive gear to perform the backwash operation; the backwash sewage is discharged through the second sewage discharge control valve of the filter tank, and the operation state is restored after the cleaning is completed. The control system automatically adjusts the opening of the first water inlet control valve, the second water inlet control valve, the first water outlet control valve, and the second water outlet control valve according to the flow requirements.

[0021] S3: The operating load is low, and the filter is shut down and backwashed. The process is as follows: the first filter is in normal operation and the second filter is in shut down and backwashed. At this time, the first water inlet control valve, the second water inlet control valve, the first water outlet control valve, the air source control valve, and the exhaust control valve are all in the open state, the second water outlet control valve is in the closed state, and the second sewage control valve is in the open state. At this time, the control system is adjusted:

[0022] (1) The upper and lower variable pitch impellers adjust the blade direction to be perpendicular to the water flow to form the maximum thrust to drive the filter cartridge drive shaft and the filter cartridge cleaning brush;

[0023] (2) The circulating thrust pump pushes the swirl blades provided on the swirl guide rod, and then transmits the rotational power to the filter cartridge drive shaft and the filter cartridge cleaning brush through the forward drive gear;

[0024] (3) The impact effect of the compressed gas explosion process distributed by the aeration disturbance cylinder removes stubborn impurity particles attached to the filter cartridge;

[0025] (4) The circulating reflux pump pushes the upper variable pitch blade of the filter cartridge drive shaft to form an auxiliary thrust to drive the swirl blades, and then evenly transmits the rotational power to several filter cartridge drive shafts and filter cartridge cleaning brushes through the forward drive gear to perform the shutdown backwashing operation process; the backwash sewage is discharged through the second sewage discharge control valve of the filter tank body, and the operation state is restored after the cleaning is completed. The control system automatically adjusts the opening of the first water inlet control valve, the second water inlet control valve, the first water outlet control valve, and the second water outlet control valve according to the flow requirements.

[0026] S4: The control system can automatically control the filter backwashing operation process according to the feedback data of the filter inlet and outlet pressure transmitters and the load status of the seawater desalination device, which can specifically achieve:

[0027] (1) Two filters run simultaneously;

[0028] (2) One filter is running while the other is backwashing;

[0029] (3) Both filters are in backwash operation;

[0030] (4) When one filter is running and the other is shut down for backwashing, in order to avoid flow interruption accidents in the feed system and the spray system, the control system sets control logic to prohibit the two filters from being shut down for backwashing at the same time.

[0031] The advantages of the present invention are as follows: Compared with the existing technology, the advantages and effects of the present invention are as follows:

[0032] 1. After the implementation of the present invention, the safe and stable operation of the seawater desalination device can be effectively guaranteed, and the frequency of nozzle disassembly and cleaning can be reduced. The present invention has the advantages of flexible operation, convenient disassembly, stable performance, high backwashing efficiency, short downtime, low maintenance cost and significant comprehensive effect.

[0033] 2. The present invention can automatically control the filter backwashing operation process according to the feedback data of the filter inlet and outlet pressure transmitters and the load status of the seawater desalination device, and can specifically achieve:

[0034] (1) Two filters run simultaneously;

[0035] (2) One filter is running while the other is backwashing;

[0036] (3) Both filters are in backwash operation;

[0037] (4) One filter is in operation while the other is shut down for backwashing.

[0038] In order to avoid interruption accidents in the feeding system and the spraying system, the control system sets the control logic to prohibit the two filters from being in the shutdown backwash state at the same time.

[0039] 3. The present invention has a small footprint, good filtering effect, simple cleaning process, short downtime period, high degree of automation, and can achieve continuous, efficient and stable operation.

[0040] 4. The aeration disturbance cylinders in the present invention are respectively arranged outside the filter cartridges. The aeration disturbance cylinder structure is an air hole screen with a hollow interior, which is used to distribute the impact effect generated by the compressed gas explosion process to remove the stubborn impurity particles attached to the filter cartridges.

[0041] 5. The upper variable pitch impeller and the lower variable pitch impeller in the present invention can freely adjust the blade direction according to the control system command. The vertical midpoint of the upper variable pitch impeller coincides with the vertical midpoint of the upper fixed partition of the filter cartridge, and the vertical midpoint of the lower variable pitch impeller coincides with the vertical midpoint of the lower fixed partition of the filter cartridge, thereby ensuring that the water flow entering the filter cartridge forms the maximum thrust through the impeller arrangement position, which is used to drive the upper and lower variable pitch impellers to drive the filter cartridge drive shaft and the filter cartridge cleaning brush arranged on the upper part to perform the backwash operation process.

[0042] 6. The swirl guide rod in the present invention is located at the center of the filter structure, and a swirl blade is arranged at the bottom thereof. The circulating thrust pump pushes the swirl blade arranged on the swirl guide rod, and then the rotational power of the rotating guide rod is evenly transmitted to several filter cartridge drive shafts and filter cartridge cleaning brushes through the forward driving gear, and the backwash operation process is implemented synchronously.

[0043] 7. The circulating reflux pump in the present invention is arranged in the water inlet chamber of the filter, and its outlet pipe directly corresponds to the upper variable pitch blade of the filter cartridge drive shaft, which is used to form an auxiliary thrust to drive the swirl blade and then evenly transmit the rotational power to several filter cartridge drive shafts and filter cartridge cleaning brushes through the forward drive gear.

[0044] 8. The present invention comprises a plurality of filter cartridges, and the filter cartridges are vertically transparent columnar filter screens, and reinforcing ribs are arranged inside the filter screens to ensure strength and avoid erosion and deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 It is a structural schematic diagram of the present invention;

[0047] in:

[0048] 1. First filter; 2. First water inlet control valve; 3. First water outlet control valve; 4. First sewage control valve; 5. Second filter; 6. Second water inlet control valve; 7. Second water outlet control valve; 8. Second sewage control valve; 9. First inlet pressure transmitter; 10. First outlet pressure transmitter; 11. Second inlet pressure transmitter; 12. Second outlet pressure transmitter; 13. Exhaust control valve; 14. Upper fixed baffle of filter cartridge; 15. Lower fixed baffle of filter cartridge Partition; 16, filter cartridge; 17, cartridge cleaning brush; 18, aeration disturbance cylinder; 19, upper variable pitch impeller; 20, lower variable pitch impeller; 21, thrust bearing; 22, circulation thrust pump; 23, forward drive gear; 24, swirl guide rod; 25, circulation reflux pump; 26, air source control valve; 27, control system; 28, reflux control valve; 29, end cover tightener; 30, end cover fixing lock pin; 31, filter cartridge drive shaft; 32, end cover fixing hinge; DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] Embodiment 1:

[0052] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1 The automatic backwashing filter device of a low-temperature multi-effect seawater desalination system shown in the figure includes a first filter 1 and a second filter 5. The upper variable pitch impeller 19 and the lower variable pitch impeller 20 in the present invention can freely adjust the blade direction according to the instruction of the control system 27. The vertical midpoint of the upper variable pitch impeller 19 coincides with the vertical midpoint of the upper fixed baffle 14 of the filter cartridge, and the vertical midpoint of the lower variable pitch impeller 20 coincides with the vertical midpoint of the lower fixed baffle 15 of the filter cartridge, so as to ensure that the water flow entering the filter cartridge forms a maximum thrust through the impeller arrangement position, which is used to drive the upper and lower variable pitch impellers 20 to drive the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17 arranged on the upper part thereof to perform a backwashing operation process. The swirl guide rod 24 in the present invention is located at the center of the filter structure, and a swirl blade is arranged at the bottom thereof. The circulating thrust pump 22 pushes the swirl blade arranged on the swirl guide rod 24, and then the rotational power is evenly transmitted to the rotational power of the rotating guide rod through the forward drive gear 23 to a plurality of filter cartridge drive shafts 31 and the filter cartridge cleaning brush 17, and the backwashing operation process is implemented synchronously.

[0053] Embodiment 2:

[0054] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1The automatic backwash filter device of a low-temperature multi-effect seawater desalination system shown in the figure includes a first filter 1 and a second filter 5. The circulating reflux pump 25 in the present invention is arranged in the water inlet chamber of the filter, and its outlet pipe directly corresponds to the upper variable pitch blade of the filter cartridge drive shaft 31, which is used to form an auxiliary thrust to drive the swirl blade and then evenly transmit the rotational power to a plurality of filter cartridge drive shafts 31 and the filter cartridge cleaning brush 17 through the forward drive gear 23. The present invention is also provided with an end cover presser 29, an end cover fixing lock pin 30, and an end cover fixing hinge 32, which are respectively arranged on the top end cover of the filter, and the end cover fixing hinge 32 is arranged at any end of the top end cover of the filter to contact The bonding surface is used to provide a supporting fulcrum during the folding and opening process of the filter end cover; the end cover fixing locking pin 30 is arranged on the symmetrical side of the position of the end cover fixing hinge 32 at the top of the filter, and is used to assist the end cover clamp 29 in fixing the filter end cover; the end cover clamp 29 includes an end cover clamping guide rod, an end cover clamping handle, an end cover clamping bolt, etc. The end cover clamping bolt is located at the center of the spherical surface of the filter end cover and is perpendicular to the spherical surface. The filter end cover is evenly tightened or loosened by rotating the end cover clamping handle. In addition, the end cover fixing hinge 32 and the end cover fixing locking pin 30 are used to realize the rapid opening and closing of the filter end cover, which is convenient for replacing and inspecting the internal components of the filter.

[0055] Embodiment 3:

[0056] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1 The present invention is a low-temperature multi-effect seawater desalination system automatic backwash filtering device, comprising a first filter 1 and a second filter 5. The present invention is applicable to the fields of petroleum, chemical industry, water treatment and other industries. The present invention is only selected for the economic and practical conditions of the site. The first filter 1 and the second filter 5 in the present invention are connected by a mother pipe connection method to realize mutual standby status. The filter commissioning status can also be freely adjusted according to the actual operation of the seawater desalination device, but at least one filter is guaranteed to be in operation; the present invention is only selected for the economic and practical conditions of the site. The present invention includes a plurality of filter cartridges 16. The filter screen thickness, hole diameter, opening rate, etc. in the present invention can be freely adjusted according to actual conditions. The present invention is only selected for the economic and practical conditions of the site. The end cover clamp 29, the end cover fixing lock pin 30, and the end cover fixing hinge 32 of the present invention are respectively arranged on the top end cover of the filter. On this basis, slight modifications can be made to realize the rapid opening and closing of the filter end cover. The present invention is only selected for the economic and practical conditions of the site.

[0057] Embodiment 4:

[0058] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1The present invention is a low-temperature multi-effect seawater desalination system automatic backwashing filter device, comprising a first filter 1 and a second filter 5. The present invention can be freely adjusted according to the operating state of the seawater desalination device. The present invention is only selected for the economic and practical situation of the site. The present invention can adopt other forms of aeration according to the specific actual situation. The present invention is only selected for the economic and practical situation of the site. The present invention comprises a plurality of filter cartridges 16. The filter cartridges 16 are a columnar structure filter screen that is transparent from top to bottom. Reinforcement ribs are arranged inside the filter screen to ensure strength and avoid scouring and deformation. After the implementation of the present invention, the safe and stable operation of the seawater desalination device can be effectively guaranteed, and the frequency of nozzle disassembly and cleaning can be reduced. The present invention has the advantages of flexible operation, convenient disassembly, stable performance, high backwashing efficiency, short downtime, low maintenance cost and significant comprehensive effect. The present invention can automatically control the filter backwashing operation process according to the feedback data of the filter inlet and outlet pressure transmitters and the load state of the seawater desalination device, and can specifically realize (1) two filters running at the same time; (2) one filter running and the other filter running backwashing; (3) both filters are in operation backwashing; (4) one filter running and the other filter stopping backwashing. In order to avoid the interruption of the feeding system and the spraying system, the control system 27 sets the control logic to prohibit the two filters from being in the shutdown backwash state at the same time. The present invention has a small footprint, good filtering effect, simple cleaning process, short shutdown cycle, high degree of automation, and can achieve continuous, efficient and stable operation.

[0059] Embodiment 5:

[0060] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1 The automatic backwashing filter device of a low-temperature multi-effect seawater desalination system shown in the figure includes a first filter 1 and a second filter 5. The upper variable pitch impeller 19 and the lower variable pitch impeller 20 can freely adjust the blade direction according to the command of the control system 27. The vertical midpoint of the upper variable pitch impeller 19 coincides with the vertical midpoint of the upper fixed baffle 14 of the filter cartridge, and the vertical midpoint of the lower variable pitch impeller 20 coincides with the vertical midpoint of the lower fixed baffle 15 of the filter cartridge, so as to ensure that the water flow entering the filter cartridge forms the maximum thrust through the impeller arrangement position, which is used to drive the upper and lower variable pitch impellers 20 to drive the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17 arranged on the upper part thereof to perform backwashing operation The present invention relates to a process in which a swirl guide rod 24 is located at the center of a filter structure, and a swirl blade is arranged at the bottom thereof. A circulating thrust pump 22 pushes the swirl blade arranged on the swirl guide rod 24, and then the rotational power is evenly transmitted to a plurality of filter cartridge drive shafts 31 and filter cartridge cleaning brushes 17 through a forward drive gear 23, and a backwashing operation process is implemented synchronously. The outlet pipe directly corresponds to the upper variable pitch blade of the filter cartridge drive shaft 31, and is used to form an auxiliary thrust to drive the swirl blade, and then evenly transmit the rotational power to a plurality of filter cartridge drive shafts 31 and filter cartridge cleaning brushes 17 through the forward drive gear 23.

[0061] Embodiment 6:

[0062] Figure 1 It is a structural schematic diagram of the present invention, such as Figure 1 The present invention shows an automatic backwashing filter device for a low-temperature multi-effect seawater desalination system, comprising a first filter 1 and a second filter 5. The present invention also includes an end cover presser 29, an end cover fixing lock pin 30, and an end cover fixing hinge 32, which are respectively arranged on the top end cover of the filter. The end cover fixing hinge 32 is arranged on a contact joint surface at any end of the top end cover of the filter, and is used to provide a support fulcrum during the folding and opening process of the filter end cover; the end cover fixing lock pin 30 is arranged on a symmetrical side of the position of the end cover fixing hinge 32 at the top of the filter, and is used to assist the end cover presser 29 in fixing The filter end cover is fixed; the end cover clamp 29 includes an end cover clamping guide rod, an end cover clamping handle, an end cover clamping bolt, etc. The end cover clamping bolt is located at the center of the filter end cover sphere and is perpendicular to the sphere. The filter end cover is evenly tightened or loosened by rotating the end cover clamping handle. In addition, the filter end cover is quickly opened and closed in conjunction with the end cover fixing hinge 32 and the end cover fixing locking pin 30, which is convenient for replacing and inspecting the internal components of the filter. The filter cartridge 16 is a columnar structure filter screen that is transparent from top to bottom, and reinforcing ribs are arranged inside the filter screen to ensure strength and avoid scouring and deformation.

[0063] Working method: The present invention comprises the following steps when used:

[0064] S1: First, the first filter 1 and the second filter 5 are operated simultaneously. At this time, the first water inlet control valve 2, the second water inlet control valve 6, the first water outlet control valve 3, and the second water outlet control valve 7 are all in the open state, and the first sewage control valve 4 and the second sewage control valve 8 are in the closed state. The original seawater or concentrated seawater flows in through the inlet ends of the first filter 1 and the second filter 5, respectively, and flows out from the outlet ends of the first filter 1 and the second filter 5.

[0065] S2: The operating load is high, and the filter performs the backwashing process in the operating state: the first filter 1 operates normally and the second filter 5 operates in the backwashing state. At this time, the first water inlet control valve 2, the second water inlet control valve 6, the first water outlet control valve 3, and the second water outlet control valve 7 are all in the open state, and the second sewage control valve 8 is in the open state. At this time, the control system 27 is adjusted:

[0066] (1) The up and down variable pitch impeller 20 adjusts the blade direction to be perpendicular to the water flow to form the maximum thrust to drive the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17;

[0067] (2) The circulating thrust pump 22 pushes the swirl blades provided on the swirl guide rod 24, and then transmits the rotational power to the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17 through the forward drive gear 23 to perform the backwashing operation; the backwashing sewage is discharged through the second sewage discharge control valve 8 of the filter tank body, and the operation state is restored after the cleaning is completed. The control system 27 automatically adjusts the opening of the first water inlet control valve 2, the second water inlet control valve 6, the first water outlet control valve 3, and the second water outlet control valve 7 according to the flow requirements.

[0068] S3: The operating load is low, and the filter performs the backwashing process in the shutdown state: the first filter 1 operates normally and the second filter 5 is in the shutdown backwashing state. At this time, the first water inlet control valve 2, the second water inlet control valve 6, the first water outlet control valve 3, the air source control valve 26, and the exhaust control valve 13 are all in the open state, the second water outlet control valve 7 is in the closed state, and the second sewage control valve 8 is in the open state. At this time, the control system 27 is adjusted:

[0069] (1) The upper variable pitch impeller 19 and the lower variable pitch impeller 20 adjust the blade direction to be perpendicular to the water flow to form the maximum thrust to drive the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17;

[0070] (2) The circulating thrust pump 22 pushes the swirl blades provided on the swirl guide rod 24, and then transmits the rotational power to the filter cartridge drive shaft 31 and the filter cartridge cleaning brush 17 through the forward drive gear 23;

[0071] (3) The impact effect generated by the explosion process of the compressed gas distributed by the aeration disturbance cylinder 18 removes the stubborn impurity particles attached to the filter cartridge 16;

[0072] (4) The circulating reflux pump 25 pushes the upper variable pitch blade of the filter cartridge drive shaft 31 to form an auxiliary thrust to drive the swirl blades and then evenly transmit the rotational power to a number of filter cartridge drive shafts 31 and the filter cartridge cleaning brush 17 through the forward drive gear 23 to perform a shutdown backwashing operation; the backwash sewage is discharged through the second sewage discharge control valve 8 of the filter tank body, and the operation state is restored after the cleaning is completed. The control system 27 automatically adjusts the opening of the first water inlet control valve 2, the second water inlet control valve 6, the first water outlet control valve 3, and the second water outlet control valve 7 according to the flow requirements.

[0073] S4: The control system 27 can automatically control the filter backwashing operation process according to the feedback data of the filter inlet and outlet pressure transmitters and the load status of the seawater desalination device, which can specifically achieve:

[0074] (1) Two filters run simultaneously;

[0075] (2) One filter is running while the other is backwashing;

[0076] (3) Both filters are in backwash operation;

[0077] (4) One filter is running while the other is shut down for backwashing. To avoid flow interruption accidents in the feed system and the spray system, the control system 27 is configured with control logic to prohibit the two filters from being shut down for backwashing at the same time.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic backwash filter device for a low-temperature multi-effect seawater desalination system, comprising a first filter (1) and a second filter (5), characterized in that: The first filter (1) and the second filter (5) are connected to each other via a pipeline; a first sewage discharge control valve (4) and a second sewage discharge control valve (8) are connected to the lower ends of the first filter (1) and the second filter (5), respectively; a filter cartridge (16) is arranged inside the first filter (1) and the second filter (5); an upper filter cartridge fixed baffle (14) is fixedly connected to the upper end of the filter cartridge (16); a lower filter cartridge fixed baffle (15) is fixedly connected to the lower end of the filter cartridge (16); an upper variable pitch impeller (19) is installed on the inner side of the upper filter cartridge fixed baffle (14); a lower variable pitch impeller (20) is installed on the outer side of the lower filter cartridge fixed baffle (15); a swirl guide rod (24) is arranged inside the filter cartridge (16); and a plurality of swirl blades are installed on the swirl guide rod (24); An aeration disturbance cylinder (18) is arranged outside the filter cartridge (16), and the internal structure of the aeration disturbance cylinder (18) is a hollow pore screen, which is used to distribute the impact effect generated by the compressed gas explosion process to remove stubborn impurity particles attached to the filter cartridge (16); A thrust bearing (21) is installed inside the filter cartridge (16), and the upper variable pitch impeller (19) and the lower variable pitch impeller (20) are coaxially connected to the upper and lower ends of the thrust bearing (21).

2. The automatic backwash filter device for a low-temperature multi-effect seawater desalination system according to claim 1, characterized in that: The first filter (1) and the second filter (5) each have an inlet end and an outlet end, and a first water inlet control valve (2) and a second water inlet control valve (6) are respectively installed on the inlet ends of the first filter (1) and the second filter (5), and a first water outlet control valve (3) and a second water outlet control valve (7) are respectively installed on the outlet ends of the first filter (1) and the second filter (5).

3. The automatic backwashing filter device for a low-temperature multi-effect seawater desalination system according to claim 2 is characterized in that: A first inlet pressure transmitter (9) is installed on the inlet end of the first filter (1), a first outlet pressure transmitter (10) is installed on the outlet end of the first filter (1), a second inlet pressure transmitter (11) is installed on the inlet end of the second filter (5), and a second outlet pressure transmitter (12) is installed on the outlet end of the second filter (5).

4. The automatic backwashing filter device for a low-temperature multi-effect seawater desalination system according to claim 1 is characterized in that: The filter cartridge (16) is a vertically transparent columnar filter screen, and a plurality of reinforcing ribs are arranged inside the filter screen.

5. The automatic backwashing filter device for a low-temperature multi-effect seawater desalination system according to claim 1 is characterized in that: A circulating reflux pump (25) is installed on one side of the filter cartridge (16), and the circulating reflux pump (25) is used to push the upper variable pitch blades.

6. The automatic backwashing filter device for a low-temperature multi-effect seawater desalination system according to claim 1 is characterized in that: The tops of the first filter (1) and the second filter (5) are both connected to exhaust control valves (13).

7. The automatic backwashing filter device for a low-temperature multi-effect seawater desalination system according to claim 1 is characterized in that: One side of each of the first filter (1) and the second filter (5) is connected to a circulating thrust pump (22), and the circulating thrust pump (22) is used to push the swirl blades provided on the swirl guide rod (24).

8. A backwashing method for an automatic backwashing filter device of a low-temperature multi-effect seawater desalination system, characterized in that: The following steps are involved: S1: First, the first filter (1) and the second filter (5) are operated simultaneously. At this time, the first water inlet control valve (2), the second water inlet control valve (6), the first water outlet control valve (3), and the second water outlet control valve (7) are all in an open state, and the first sewage control valve (4) and the second sewage control valve (8) are in a closed state. The original seawater or concentrated seawater flows in through the inlet ends of the first filter (1) and the second filter (5), respectively, and flows out from the outlet ends of the first filter (1) and the second filter (5); S2: The operating load is high, and the filter performs the backwashing process in the operating state: the first filter (1) operates normally and the second filter (5) operates in the backwashing state. At this time, the first water inlet control valve (2), the second water inlet control valve (6), the first water outlet control valve (3), and the second water outlet control valve (7) are all in the open state, and the second sewage control valve (8) is in the open state. At this time, the control system (27) is adjusted: (1) The up and down variable pitch impeller (20) adjusts the blade direction to be perpendicular to the water flow to generate maximum thrust to drive the filter cartridge drive shaft (31) and the filter cartridge cleaning brush (17); (2) The circulating thrust pump (22) pushes the swirl blades provided on the swirl guide rod (24), thereby transmitting the rotational power to the filter cartridge drive shaft (31) and the filter cartridge cleaning brush (17) through the forward drive gear (23) to perform the backwashing operation process; the backwashing sewage is discharged through the second sewage discharge control valve (8) of the filter tank body, and the operation state is restored after the cleaning is completed. The control system (27) automatically adjusts the opening of the first water inlet control valve (2), the opening of the second water inlet control valve (6), the opening of the first water outlet control valve (3), and the opening of the second water outlet control valve (7) according to the flow demand; S3: The operating load is low and the filter is backwashed in a shutdown state. The first filter (1) is in normal operation and the second filter (5) is in a shutdown backwash state. At this time, the first water inlet control valve (2), the second water inlet control valve (6), the first water outlet control valve (3), the air source control valve (26), and the exhaust control valve (13) are all in an open state, the second water outlet control valve (7) is in a closed state, and the second sewage control valve (8) is in an open state. At this time, the control system (27) is adjusted as follows: (1) The upper variable pitch impeller (19) and the lower variable pitch impeller (20) adjust the blade direction to be perpendicular to the water flow to form a maximum thrust to drive the filter cartridge drive shaft (31) and the filter cartridge cleaning brush (17); (2) The circulating thrust pump (22) pushes the swirl blades provided on the swirl guide rod (24), thereby transmitting the rotational power to the filter cartridge drive shaft (31) and the filter cartridge cleaning brush (17) through the forward drive gear (23); (3) The aeration disturbance cylinder (18) distributes compressed gas to generate impact action during the explosion process to remove stubborn impurity particles attached to the filter cartridge (16); (4) The circulating return pump (25) pushes the upper variable pitch blade of the filter cartridge drive shaft (31) to form an auxiliary thrust to drive the swirl blades and then evenly transmit the rotational power to a plurality of filter cartridge drive shafts (31) and the filter cartridge cleaning brush (17) through the forward drive gear (23) to perform a shutdown backwashing operation process; the backwash sewage is discharged through the second sewage discharge control valve (8) of the filter tank body, and the operation state is restored after the cleaning is completed. The control system (27) automatically adjusts the opening of the first water inlet control valve (2), the opening of the second water inlet control valve (6), the opening of the first water outlet control valve (3), and the opening of the second water outlet control valve (7) according to the flow demand; S4: The control system (27) can automatically control the filter backwashing operation process according to the feedback data of the filter inlet and outlet pressure transmitters and the load status of the seawater desalination device, and can specifically achieve: (1) Two filters run simultaneously; (2) One filter is running while the other is backwashing; (3) Both filters are in backwash operation; (4) One filter is running while the other filter is shut down for backwashing. To avoid flow interruption accidents in the feed system and the spray system, the control system (27) is configured with control logic to prohibit the two filters from being shut down for backwashing at the same time.

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