50 results about "Filtration - action" patented technology

A method for producing a lead acid battery that operates on the oxygen cycle is disclosed. The method includes the steps of: assembling a cell comprising a positive plate, a negative plate, and a sheet of separator material which is an absorbent, porous filtration medium, so that there is free space between the plates and surfaces of the separator, inserting the cell into a case, introducing into the case a mixture of sulfuric acid and silica including silica from a never dried precipitated silica slurry, causing the sulfuric acid in the mixture in the free space to gel, and sealing the case. The sulfuric add in the mixture in the free space can be caused to gel by an increase in the silica content thereof, by an increase in the specific gravity thereof, or by both an increase in the silica content thereof, and an increase in the specific gravity thereof.

The invention discloses a membrane microalgae photobioreactor for realizing in-situ solid-liquid separation. The membrane microalgae photobioreactor comprises a liquid level balance water tank, a reactor main body, a micropore diffuser, a hollow fiber membrane assembly and a constant flow pump. In the culture method of the membrane microalgae photobioreactor, a culture solution enters the reactor main body through the liquid level balance water tank, required nutrients are provided for the growth of microalgae, the liquid level is kept constant, in-situ solid-liquid separation of a cultured algae solution is realized by using the hollow fiber membrane assembly arranged in the middle of the reactor, water is drained out of the constant flow pump through the membrane assembly under the suction filtration action of the constant flow pump, microalgae cells are kept in the reactor, and harvesting of microalgae cells is performed periodically. The novel membrane microalgae photobioreactor capable of realizing in-situ solid-liquid separation is simple in structure and convenient to operate. The membrane microalgae photobioreactor can run under a high hydraulic load while microalgae culture is performed by using effluent and the like with low nitrogen and phosphorous contents in urban sewage treatment plants, so that the running efficiency of the photobioreactor is increased greatly.

A method for producing a lead acid battery that operates on the oxygen cycle is disclosed. The method includes the steps of: assembling a cell comprising a positive plate, a negative plate, and a sheet of separator material which is an absorbent, porous filtration medium, so that there is free space between the plates and surfaces of the separator, inserting the cell into a case, introducing into the case a mixture of sulfuric acid and silica including silica from a never dried precipitated silica slurry, causing the sulfuric acid in the mixture in the free space to gel, and sealing the case. The sulfuric acid in the mixture in the free space can be caused to gel by an increase in the silica content thereof, by an increase in the specific gravity thereof, or by both an increase in the silica content thereof, and an increase in the specific gravity thereof.

The invention discloses an apparatus for collecting and recovering garbage in rivers and lakes, comprising a tank (1); a water inlet (6) is arranged at the top of the tank (1); a turbine pump (2) is arranged below the tank (1); chute-shaped turbine blades (3) are arranged inside the turbine pump (2); a motor (4) for driving the rotation of the turbine blades (3) is arranged at the bottom of the turbine pump (2); and a sieve plate (5) is arranged above the turbine blades (3); filtration holes (10) are densely distributed in the sieve plate (5). According to the invention, driven by water, the garbage flows into the apparatus; after filtration by the sieve plate (5), water and garbage are separated, water is discharged, and the garbage is left in the apparatus as a raw material for recovery, thereby effectively solving the problem of collecting and recovering garbage in rivers and lakes in cities.

The invention relates to a high-efficiency energy-saving processing method of a sweet potato juice, which comprises the following steps: peeling the raw material sweet potatoes, crushing, heating, and gelatinizing to obtain a sweet potato pulp, carrying out high-temperature enzymolysis on the sweet potato pulp, pressing the sweet potato pulp to obtain a sweet potato juice and peel trimmings, and carrying out after-treatment on the sweet potato juice to obtain the sweet potato juice finished product. The method is characterized in that the sweet potatoes are crushed and extruded, the extruded sweet potatoes are heated and gelatinized, and the extruded sweet potato juice is used as spray water in the pressing process; and wood fibers is mixed and added in the sweet potato pulp pressing process. According to the method, the sweet potatoes are directly extruded after being crushed, and the extruded sweet potato juice is used as spray water for gelatinization, so that no water is additionally added, thereby saving the time and energy consumption; and meanwhile, the wood fibers, which have smooth surface and have not burrs, are added in the sweet potato pressing process and can fully display the filtration action in the pressing process, so that the juice in the sweet potato trimmings can be sufficiently extruded, thereby enhancing the juice yield of the sweet potato trimmings.

The invention belongs to the field of sewage treatment and particularly relates to a sewage treatment method and device which are integrated with sequencing-batch type operation, mobile-bed biofilm process and deep-bed filtration. The device comprises a reactor body, grained media filter and a movable catchment component which is still smaller than water in proportion after biofilm formation. The reactor performs operations on water inflowing, reacting, standing and water outflowing according to the sequencing batch type, and pollutants in inflowing water are degraded or mineralized under common action of a biofilm and activated sludge in the reactor; during the standing period, when a bed layer of certain thickness is formed in a floating manner on the media filter loading the biofilm, water subjected to reacting is enabled to move upwards relative to the bed layer of the media filler, solid-liquid separation of the inflowing water is strengthened through filtration of the bed layer of the media filler, and the water penetrating the bed layer of the media filler is led out from the reactor to become reacted inflowing water. The reactor completing water outflowing can enter the operation period of the next sequencing batch. The sequencing-batch type mobile filtration bed sewage treatment method and device is specially suitable for treatment of domestic sewage of small and tiny type villages.

The invention discloses a pet loo, relates to the technical field of pet supplies, and solves the technical problem that a pet loo in the prior art has low utilization rate for pet excrement treatmentconsumables and is not intelligent. The pet loo comprises a roller assembly and a transmission mechanism, wherein the roller assembly is internally provided with a sieve plate, the sieve plate is provided with meshes with the sizes greater than those of the excrement treatment consumables and less than that of pet excrement, and the transmission mechanism drives the roller assembly to rotate forward or backward, so that the roller assembly controls the discharge of the pet excrement or the excrement treatment consumables through the filtration action of the meshes separately. The pet loo hasthe advantages that after a pet uses the loo, the remaining excrement treatment consumables can continue to be stored in the roller assembly for standby application, thereby increasing the utilizationrate of the excrement treatment consumables, and the transmission mechanism drives the roller assembly to rotate, thereby improving the automation of the pet excrement treatment process.

The invention provides a network security accessing and sealing method and device based on an FPGA (field programmable gate array). The device comprises a network data memory, a user rule memory and a characteristic comparator. The method comprises the steps of receiving an external network data packet, and momentarily memorizing the data packet in a network data memorizer; detecting the characteristic value of the network data packet, wherein the characteristic value comprises a source directory IP (internet protocol) address, a source directory port and a protocol, and monitoring the control bit of a message; querying a corresponding action of the hit data packet with the characteristic value which is coincident with the set source directory IP address, the set source directory port and the set protocol, analyzing the packet header information and the filtration action according to a rule filtering result, and judging whether to transmit the sealing packets and which types of the sealing packets to be transmitted; and transmitting the data packet forged by the construction of the packet transmitting action, and interrupting the network access. After the method is used, the security accessing and sealing are realized, and the ping pang operation is adopted when the data packet is written and read, so that the processing speed of the data flow is increased. The illegal TCP (transmission control protocol) access is interrupted by transmitting the forged data packet, and the access of some illegal networks can be effectively interrupted, so that the safety performance of the network is improved.

The invention relates to a method for coating a paper substrate with silicon dioxide directly. Under normal temperature and pressure, a binding agent containing starch is completely dissolved in deionized water, and silicon dioxide is added to prepare a solution with uniformly dispersed coating materials; the surface of the paper substrate is uniformly coated with the solution with uniformly dispersed coating materials with a suction filtration coating method, and the surface of the paper substrate is uniformly coated with one layer of silicon dioxide particles under the bonding action of the binding agent of the starch and the like and the suction filtration action of a suction filtration pump; according to the method, the surface of the paper substrate can also be uniformly coated with other oxide particles, carbon nanotubes, polymer materials, metal powder and the like; the method has the advantages that the operation is simple and convenient, raw materials are easy to obtain, the equipment is simple, the prepared paper surface properties are uniform, mass production is easy, the preparation process is green and environment-friendly and the like.

The invention relates to reuse equipment and a method for wickerwork printing and dyeing wastewater treatment. The equipment comprises a wastewater pond, a coagulative precipitation tank, a fiber rotary disc filter pond and a clean water pond, wherein wastewater generated in a wickerwork printing and dyeing process flows into the wastewater pond, a lifting pump is arranged in the wastewater pond,the wastewater is pumped into the coagulative precipitation tank through the lifting pump, a coagulant and a coagulant aid are input in the coagulative precipitation tank, and after flocculation and precipitation reactions, the precipitate enters a sludge dewatering equipment for compressing, dehydrating and transferring the precipitate; the precipitated supernate enters the fiber rotary disc filter pond through a decanter, the filter rotary disc filter pond intercepts suspended solids in the supernate under the filtration action of filter cloth, filtered water enters the clean water pond, andthe filtered water enters the wickerwork printing and dyeing process to be reused.

The invention is suitable for the field of image processing and provides a target locating method and device as well as an image display device. The method comprises the following steps: obtaining a pixel coordinate of an image formed by a monochrome light source on a target on a photosensitive element, and then calculating a space coordinate of the monochrome light source on the target according to the pixel coordinate of the image and the space coordinate of an optical imaging element, wherein the image is the image leaved on the photosensitive element after the monochrome light source passes through the optical imaging element on the image display device, and the optical imaging element comprises a convex lens or a small hole containing a film optical filter. According to the embodiment of the invention, the image display device is used for calculating the space coordinate of the monochrome light source by obtaining the pixel coordinate of the image formed by the monochrome light source on the target on the photosensitive element; the speed of analyzing the monochrome light source is high; and under the filtration action of the optical filter, the problem of easily formed interference among lights is solved.

The invention relates to a high-efficiency biological aerated filter (BAF) device used for explosive wastewater treatment, belongs to the field of wastewater treatment, and aims to effectively overcome the defects during the explosive wastewater reuse of complex treatment process, high treatment cost and the like of ammonia nitrogen and organic matter degradation; the device comprises a water intake system, a water discharge system, an aerating system, a backwash water intake system, a backwash water discharge system, a supporting layer and a filler layer. According to the high-efficiency biological aerated filter (BAF) device used for explosive wastewater treatment, the physicochemical process and the biochemical process are combined, fine suspended matters are intercepted under the adsorptive filtration action of the filler, and most of ammonia nitrogen and organic pollutants are removed under the internal and external biochemical treatment action of the filler, and the condition that effluent can reach the standard and be reused is ensured; besides, the device is low in cost and good in treatment effect, ammonia nitrogen after wastewater treatment is reduced to be 5 mg / L or below, and COD is smaller than 50 mg / L.

The invention relates to a concentrated filtering device and a cleaning method of filter elements. The concentrated filtering device comprises a filtering water tank, a filtering component, a water producing tank, a water intake pump and a back flush device, wherein the filtering component is arranged in the filtering water tank; the back flush device is used for back flushing the filtering component; the filtering component comprises a plurality of cylindrical filter elements which are arranged vertically and are parallel mutually; components playing a filtering role in the filter elements are filtering membranes; the plurality of filter elements are communicated with the water producing tank through a water generating pipeline so as to form a water producing passage; and the water producing passage is provided with a control valve; especially the back flush device comprises a gas generating device for providing gas to the filtering component so as to implement gas flushing for the filtering elements. According to the invention, a gas flushing back flush mode is adopted, the water producing rate can be improved, and the operation cost is lowered; and meanwhile, the device is simpler, the cost is lowered, and the operation is more convenient.

The invention discloses an efficient activated sludge interception type secondary sedimentation tank process system with a coupled deep filtration function. According to the invention, a water delivery system communicates with the efficient activated sludge interception type secondary sedimentation tank having the coupled deep filtration function; and the efficient activated sludge interception type secondary sedimentation tank with the coupled deep filtration function comprises a tank body, a water inlet pipe, a water distribution system, an overflow weir, a slag blocking plate, a slag scraping plate, a mud scraping plate, a driving motor, a stirring device and a coupling filter tank. The system has the functions of net compensation, flocculent precipitation and filtration, also has the functions of mud-water separation, chemical phosphorus removal and deep filtration, can obviously improve the mud-water separation effect of a secondary sedimentation tank and reduce the hydraulic retention time and occupied area of the secondary sedimentation tank, and is coupled with a deep filtration system, so secondary lifting energy consumption is saved, and corresponding sewage pipelines aresaved.

The invention belongs to the field of filtration, and particularly relates to a use method of a filtering membrane assembly. A filtering device comprises a machine body, the bottom of the machine body is fixedly connected with a water outlet pipe, the upper surface of the machine body is fixedly connected with an outer cover, the upper surface of the outer cover is fixedly connected with a water inlet pipe, and the lower surface of the outer cover is fixedly connected with a main blow-off pipe. According to the use method of the filtering membrane assembly, by arranging a centrifugal mechanism, when fluid filtered by a standing mechanism and an adjusting mechanism flows to the centrifugal mechanism from a sieve plate, a turbine drives a roller to rotate under the action of fluid impact force, and the fluid flows out from a through hole in the top of the roller under the influence of centrifugal force; and settled impurities flow into the bottom cover from the through hole in the bottom of the roller and are finally discharged from an auxiliary blow-off pipe, and the fluid subjected to multi-stage filtration finally flows out of a water outlet pipe under the adsorption filtration action of a multilayer plate and activated carbon, so that the problems of single-stage filtration and poor filtration effect of traditional filtration equipment are solved.

The invention discloses a water-saving type height-adjustable organic vegetable irrigating device. The water-saving type height-adjustable organic vegetable irrigating device comprises a workbench. A cabinet is connected to the bottom of the workbench fixedly. A motor is mounted in the cabinet fixedly. A first conveying belt is in transmission connection with the output end of the motor. One side of the first conveying belt is in transmission connection with one side of a first pulley in the workbench. A fixing shaft is inserted to the axis of the first pulley movably. The water-saving type height-adjustable organic vegetable irrigating device has the advantages that through a liquid collecting groove, a sleeve and a filter screen, water in a water tank flows into a water pipe by turning on a water pump and a valve, and organic vegetables are watered by a water spray head; water overflowing from a planting frame is collected by the liquid collecting groove, returns into the water tank through a guide pipe and is recycled under the filtration action of the filter screen, so that economy and practicability are achieved, water resource is saved greatly, and planting cost is reduced.

The invention is applicable to the technical field of filtration, and provides a multi-medium filter which comprises a sleeve-shaped barrel, a liftable filter frame is arranged in the barrel, the filter frame is sequentially divided into a plurality of filter layers from top to bottom, and a containing barrel for containing filtered media is slidably inserted into each filter layer; according to the multi-medium filter, the containing barrels are arranged to contain filtered media, each medium corresponds to one containing barrel to be contained, the media can be independently extracted and replaced, the multiple containing barrels stacked along the side plates carry out random combination and arrangement control on the filtering media according to needs, the filtering range is enlarged, and through meshing of the toothed plates and the gears on the side plates and arrangement of the hydraulic cylinder and the motor in the vertical direction, semi-automatic replacement of all media in the containing barrel is achieved, the media can be conveniently and timely operated, and the filtering effect on liquid is prevented from being affected.

The invention relates to a tail gas filter with the good purifying effect. The tail gas filter comprises a filter tank (1). A first filter screen (2), a first ceramic honeycomb carrier (3), a second ceramic honeycomb carrier (7) and a second filter screen (8) are sequentially arranged inside the filter tank (1) in the airflow direction. The surface of honeycomb ceramics is coated with an acid-resisting coating. The tail gas filter with the good purifying effect is good in acid resistance, and tail gas with the main components being CO, HC and NOx is reacted into CO2, H2O, N2 and O2 under the four-stage filtration action of the first filter screen, the first ceramic honeycomb carrier, the second ceramic honeycomb carrier and the second filter screen. Meanwhile, black smoke particles in waste gas can be effectively filtered out through micro pores in partition walls and further be burnt under the action of catalyst coatings, and the tail gas purifying effect is further improved.

The invention relates to the technical field of oil-gas separation, in particular to a comprehensive oil-gas separation device, which comprises a rotary separation cylinder and an adsorption filtration channel, and performs three-stage separation on an oil-gas mixture in a targeted manner by virtue of the arrangement of a three-stage oil-gas separation structure. Separation of large-particle oil drops, medium-particle oil drops and gas is completed under the rotation and centrifugal action of the rotary separation cylinder, separation of small-particle oil drops and small-particle oil drops and gas is completed under the adsorption and filtration action of the adsorption and filtration channel, the oil content of finally separated gas is obviously reduced, the gas reaches the emission standard, and the gas is discharged outwards through an exhaust port. In addition, the device can be used in parallel to treat a large amount of oil-gas mixture generated in industrial production, and the device is flexible to use.

The invention relates to a method and system for removing ammonia nitrogen and organic matters in wastewater. The method comprises the following specific steps: the wastewater enters a biological aerated filter, and wastewater containing nitrate and macromolecular organic matters is obtained under the filtration action of a filter material and the treatment of microorganisms; the wastewater containing nitrate and macromolecular organic matters enters an ultraviolet irradiation tank, nitrate ions generate hydroxyl free radicals and nitrogen free radicals under the irradiation of ultraviolet rays, and the macromolecular organic matters are decomposed under the action of the hydroxyl free radicals and the nitrogen free radicals, so that small molecular substances, carbon dioxide and water areobtained. The treatment effect of the macromolecular organic matters is improved, and the method is suitable for treating wastewater with higher content of macromolecular organic matters.

The invention belongs to the field of biological metallurgy and specifically relates to a method for reducing the content of suspended particles in a biological heap leaching qualified liquid. A solution upper heap is initially started by using small flow; and an ore heap is gradually and slowly moistened by using an intermittent spraying and flow gradually-increasing mode; under the capillary actions of internal cracks of the ore heap and ore surfaces, a solution is enabled to be in contact with the ores and react with the ores in a more moderate manner within an enough long time; after the ore heap is sufficiently moistened, a filtration effect on the solution can be generated; at the moment, the intermittent spraying can be changed into continuous spraying; most suspended particles in the solution can be kept in the ore heap under the filtering effect of the ore heap, so that the content of the suspended particles in the solution which is leached from the heap can be reduced. Therefore, the purpose of controlling the TSS content of the qualified liquid is realized.

The invention discloses an operation method of an extrusion molding system after paper-plastic separation, and belongs to the technical field of waste carton treatment. The operation method comprises the specific steps as follows: plastic pieces after paper and plastic separation fall into a thruster of an extrusion molding mechanism through free falling of a feed hopper; the plastic pieces are melted into a liquid at a high temperature under continuous heating of a heater; impurities which cannot be melted fall into an impurity collecting box for temporary storage when pushed into a filter mechanism through the filtration action of the filter mechanism; generated smoke is discharged through an exhaust tube in the heating process; the plastic liquid is subjected to filtration and extrusion molding through the filter mechanism and is cooled by a cooling pond to form a strip-shaped plastic finished product suitable for being granulated and processed; and the generated smoke sequentially enters a chemical solution treatment box, a spray tower and an adsorption tank for treatment through the exhaust pipe. The aims of improving the production efficiency by recycling the plastic pieces, reducing the production cost and fully treating the smoke in the extrusion molding process are achieved.

The invention provides an intelligent environment DNA collection method which comprises the following steps: a control assembly controls a gas-liquid dual-purpose pump to carry out first suction filtration action on a water sample, so that the water sample flows through a current collection filter membrane through a water inlet pipeline and then is discharged through a water outlet pipeline, a pair of sampling equipment is rinsed, and after rinsing, the water sample is discharged through a water outlet pipeline; marking and storing the current collection filter membrane after the first suction filtration action; then, the control assembly is used for controlling the gas-liquid dual-purpose pump to perform N suction filtration actions on the water sample, and each suction filtration action in the N suction filtration actions correspondingly uses one standby filter membrane, so that the water sample flows through the corresponding standby filter membrane from the water inlet pipeline and then is discharged through the water outlet pipeline; n is an integer greater than or equal to 2; and marking and storing the standby filter membrane obtained at each time in the N suction filtration actions, so as to achieve the technical purpose of sampling the water sample through a plurality of filter membranes, thereby achieving the technical effect of improving the sampling efficiency.

This invention discloses a de-diamonds filtration method and a device used in image code-decode devices including: receiving a big diamonds pixel data output by a mobile compensation unit to divide the data into multiple pixel data and carrying out a data exchange process to the data and storing the data into a storage buffer, utilizing said pixel data in the buffer storage to filter the level pixel of the diamonds to update part of the pixel data in the buffer, and exchanging said data in the buffer and carrying out vertical pixel filtration action using the pixel data to update part of saidlarge diamonds pixel data in the buffer.

The invention discloses a filter device for self-overflowing dissolving agent sewage treatment, belonging to the technical field of sewage treatment, which can realize the introduction of sewage through the left end of the filter treatment pipe, and can filter the dissolving agent in the sewage through the setting of a non-return component. The particles play a non-return function, combined with the filtering effect of the filter screen, so that the dissolving agent particles in the sewage are intercepted between the non-return plate and the filter screen, and fall into the collection recovery pipe through the guide hopper. The setting of the material recovery component, the positive rotation of the adjustment rod can drive the movable pipe plug, movable bucket plug, and movable hole plug to move downward, so that the solvent particles in the aggregate recovery pipe can be dropped without stopping the sewage treatment. Put it into the spherical filter material net, then reverse the adjustment lever to reset, then the filtered dissolving agent particles can be taken out through the discharge hole and recovered, so that the dissolving agent particles can be easily taken out and recycled, and the sewage treatment efficiency can be improved. Significantly improved usability.

The invention provides an unpowered sewage treatment device in order to integrate pretreatment and advanced treatment of sewage and carry out aerobic biochemical treatment, anaerobic biochemical treatment and solid-liquid separation treatment on the sewage by utilizing a small altitude difference to enable the sewage to reach the discharge or reuse standard. The device comprises a water inlet pipe1, an excrement tank 2, a biochemical tank 3 and a water outlet pipe 4, a filtering system 5 is arranged in the excrement residue pool and connected with the biochemical pool 3 through a connecting pipe 9, a lower partition plate 6 and an upper partition plate 7 are arranged in the biochemical pool 3, under the filtering action of the filtering system 5, solid pollutants in sewage are interceptedin the excrement residue pool 2, the sewage enters the filtering system 5 and enters the biochemical pool 3 through the connecting pipe 9, and exchange of surface water and lower water is completed for multiple times under the action of the lower partition plate 6 and the upper partition plate 7. After aerobic, anoxic and anaerobic biochemical reactions are completed for many times to degrade pollutants, the pollutants flow out of the water outlet pipe 4.

The invention provides a mask which mainly comprises a mask body and tying belts, and the mask body comprises a wrinkle surface, a flat edge, a pull-limiting elastic line and a nose bridge strip; a wrinkle-free flat edge is arranged on the periphery of the wrinkle surface, and a tension-limiting elastic line perpendicular to each wrinkle line is arranged on the wrinkle surface; the nose bridge strip is arranged on the flat edge of the upper edge. When the mask is packaged and stored, wrinkles are folded into a plane shape, and when the mask is used, the wrinkles are opened to a certain degreeto form a bowl shape. The mask wrinkle structure ensures three-dimensional filtration, the tension-limiting elastic lines can prevent wrinkles from being flattened, the mask can be prevented from being pulled to the lower jaw and covering the neck to lose a filtration effect, and it is ensured that the filtration area is large and the inspiration resistance is small; the structure is simple, the mask conforms to ergonomics, the protection performance is good, and wearing is comfortable.

The invention discloses a preparation method of a composite air filter material, and belongs to the technical field of composite materials. Basalt, vermiculite and the like are used as raw materials,so that the filter material has a self-cleaning effect, and a nano silicon dioxide component can adsorb part of water to wet the surface of the filter material, so that the dispersion effect is improved, and the filter effect can also be well improved. Hard and soft components are combined; nanoparticles are supported, the cross-linking effect between macromolecular colloids is facilitated; hydrogen-bond interaction among the components is used; a gel layer of a nanoscale film is formed on the surface of the filter material; filtration resistance is reduced, according to the present invention,hydrogen-containing silicone oil and allyl methacrylate are adopted as raw materials, so that organic and inorganic components penetrate through each other to form a multi-layer network, and the multi-layer network has characteristics of amphipathy and large internal space so as to easily improve the filtration effect, and the problems of poor filtration effect and high filtration resistance of the existing commonly used air filtration material are solved.

The invention relates to a concentrated filtering device and a cleaning method of filter elements. The concentrated filtering device comprises a filtering water tank, a filtering component, a water producing tank, a water intake pump and a back flush device, wherein the filtering component is arranged in the filtering water tank; the back flush device is used for back flushing the filtering component; the filtering component comprises a plurality of cylindrical filter elements which are arranged vertically and are parallel mutually; components playing a filtering role in the filter elements are filtering membranes; the plurality of filter elements are communicated with the water producing tank through a water generating pipeline so as to form a water producing passage; and the water producing passage is provided with a control valve; especially the back flush device comprises a gas generating device for providing gas to the filtering component so as to implement gas flushing for the filtering elements. According to the invention, a gas flushing back flush mode is adopted, the water producing rate can be improved, and the operation cost is lowered; and meanwhile, the device is simpler, the cost is lowered, and the operation is more convenient.