Negative pressure bending flow separation pipe

Abstract

The invention belongs to the field of recirculating aquaculture equipment, and particularly relates to a negative pressure bending flow separation pipe. The negative pressure bending flow separation pipe is mounted at the front end of a water inlet of the microfilter and comprises a separation pipe body, a return pipe and a plurality of bent pipes. The separation pipe body is of a spiral structure. The separation pipe body is provided with a cylindrical cavity, the backflow pipe is installed in the cylindrical cavity, one end of the bent pipe is communicated with the separation pipe body, and the other end is bent downwards and communicated with the backflow pipe. The tail water entering the separation pipe body can rotate and flow upwards along the separation pipe body. At the joint of the separation pipe body and the bent pipe, solid particles can flow to the return pipe along the bent pipe on the inner side of the separation pipe body by utilizing the principle that solid and liquid are distributed differently in the turning process of water flow, and the liquid can rotate upwards and flow along the separation pipe body. Therefore, solid-liquid separation of the tail water is realized, the problem that solid particles in the tail water are easy to block the micro-filter after entering the micro-filter is avoided, and the filtering stability of the micro-filter is improved.

Description

Technical Field

[0001] The invention belongs to the field of aquaculture equipment, and in particular relates to a negative pressure curved flow separation pipe. Background Art

[0002] The recirculating aquaculture system is a new type of aquaculture model, which uses a series of water treatment units to treat the wastewater generated in the aquaculture pond and then recycle it for reuse. The main principle of the recirculating aquaculture system is to integrate advanced technologies in the fields of environmental engineering, civil engineering, modern biology, electronic information, etc., in order to remove harmful pollutants such as residual bait, feces, ammonia nitrogen, nitrite nitrogen, etc. in the aquaculture water body and purify the aquaculture environment. It uses physical filtration, biological filtration, CO2 removal, disinfection, oxygenation, temperature control and other treatments to make the purified water body comfortable again in the aquaculture pond. It can not only solve the problem of low water resource utilization, but also provide a stable, reliable, comfortable and oily living environment for aquaculture organisms, and provide favorable conditions for high-density aquaculture.

[0003] In existing recirculating aquaculture systems, tail water from aquaculture is generally filtered through a microfilter. The tail water generally contains a large amount of fish bait and feces. These solid particles can clog the microfilter, thereby greatly reducing the filtration efficiency of the microfilter. Summary of the invention

[0004] In order to solve the technical problem in the prior art that a microfilter in a circulating aquaculture system is easily clogged and thus leads to poor filtering efficiency, the present invention provides a negative pressure curved flow separation tube.

[0005] The present invention is implemented by the following technical scheme: a negative pressure curved flow separation pipe, which is installed at the front end of the water inlet of the microfilter and is used for solid-liquid separation of tail water entering the microfilter; the negative pressure curved flow separation pipe comprises: a separation pipe body, a return pipe and a plurality of curved pipes, the separation pipe body is in a spiral structure, and the spiral structure makes the separation pipe body itself surround a cylindrical cavity; the lower end of the separation pipe body is connected to an inlet pipe 1, and the upper end of the separation pipe body is connected to an outlet pipe 1; the inner diameter of the separation pipe body gradually decreases from bottom to top; the return pipe is installed in the cylindrical cavity, the central axis of the return pipe coincides with the central axis of the cylindrical cavity, and the outer diameter of the return pipe is smaller than the diameter of the cylindrical cavity; a plurality of curved pipes are installed in the cylindrical cavity; one end of the curved pipe is connected to the separation pipe body, and the other end of the curved pipe is bent downward and connected to the return pipe;

[0006] The plane where the bottom surface of the return pipe is located is set as the reference plane, the center of the connection between the bent pipe and the separation pipe body is point 1, the center of the return pipe is point 2, and the straight line formed by the vertical projections of point 1 and point 2 on the reference plane is straight line 1; the angle between the vertical projection of the bent pipe on the reference plane and straight line 1 is smaller than the angle between the vertical projection of the bent pipe on the reference plane and straight line 1;

[0007] The tail water to be filtered enters from the water inlet pipe 1 at the lower end of the separation tube body, rotates upward along the separation tube body until entering the microfiltration machine from the water outlet pipe 1; at the connection between the separation tube body and the bend pipe, the solid particles in the tail water will flow along the bend pipe inside the separation tube body to the return pipe, and the liquid in the tail water will rotate upward along the separation tube body.

[0008] As a further improvement of the present invention, the ratio of the length of the separation tube body in the axial direction to the inner diameter of the separation tube body is 5:1 to 10:1.

[0009] As a further improvement of the present invention, the separation tube body includes multiple spiral circles, each of which is provided with two bent pipes, each of which is divided into two half spiral circles, the two bent pipes are respectively arranged in the two half spiral circles, and the two bent pipes in the same spiral circle are centrally symmetrical about the central axis of the return pipe.

[0010] As a further improvement of the present invention, within the semi-helical circle, the curved pipe is located at the lowest point of the turning point of the semi-helical circle.

[0011] As a further improvement of the present invention, the separation tube body includes a plurality of spiral coils, each of the spiral coils is provided with three bends, and the connection angle between the bends and the return pipe is 45°-70°.

[0012] As a further improvement of the present invention, a filter barrel is connected below the reflux pipe, and the filter barrel is rotatably connected to the reflux pipe. A plurality of filter nets are arranged in the filter barrel, and the plurality of filter nets are used to separate the solid-liquid mixed tail water entering the reflux pipe.

[0013] As a further improvement of the present invention, the water inlet pipe 1 is a three-way pipe.

[0014] As a further improvement of the present invention, the water outlet pipe 1 is a three-way pipe.

[0015] As a further improvement of the present invention, the inner diameter of the bent pipe is one quarter to one half of the inner diameter of the separation pipe body.

[0016] As a further improvement of the present invention, the separation tube body is an equal-diameter and equal-distance spiral structure, the spiral angle of the separation tube body is 30°-60°, and the inner diameter of the separation tube body gradually decreases from bottom to top, and the reduction ratio is 2%-5% for every 100mm in the vertical direction.

[0017] As a further improvement of the present invention, a water outlet pipe 2 is provided on the filter barrel, and the water outlet pipe 2 is connected to the water inlet pipe 1. The tail water filtered by the filter barrel can enter the water inlet pipe 1 along the water outlet pipe 2.

[0018] As a further improvement of the present invention, a one-way valve is provided on the water outlet pipe 2, and the one-way valve allows the water between the filter barrel and the water inlet pipe 1 to flow only from the water outlet pipe 2 of the filter barrel to the water inlet pipe 1.

[0019] The technical solution provided by the present invention has the following beneficial effects:

[0020] (1) The negative pressure curved flow separation tube of the present invention has a spiral structure of the separation tube body. At the connection between the separation tube body and the curved pipe, the difference in the distribution of solids and liquids in the water flow during the curve is used to make the solid particles in the tail water gather on the side close to the curved pipe, and the liquid in the tail water gather on the side of the separation tube body away from the curved pipe. Therefore, under the action of the rising impact of the tail water and the inertia and gravity of the solid particles during the flow, the solid particles in the tail water will enter the return pipe along the curved pipe, while the liquid in the tail water will continue to rotate and flow upward along the separation tube body. In this way, the solid particles in the tail water are removed, thereby solving the problem in the prior art that the solid particles in the tail water are easy to cause blockage to the microfilter after entering the microfilter, so that the solid particles in the tail water entering the microfilter are greatly reduced, thereby improving the filtration stability of the microfilter and extending the service life of the microfilter.

[0021] (2) The negative pressure curved flow separation tube of the present invention limits the ratio of the length of the separation tube body in the axial direction to the inner diameter of the separation tube body, so that the tail water can flow upward along the separation tube body under a relatively small driving force while ensuring that a negative pressure is generated in the separation tube body, so that the solid and liquid in the tail water entering the separation tube body can be effectively separated at the bend, thereby achieving a greater degree of solid-liquid separation in the separation tube body in the tail water while satisfying a relatively small driving force, thereby saving separation costs while also improving separation efficiency.

[0022] (3) The negative pressure curved flow separation pipe of the present invention has a filter barrel arranged below the return pipe, which can collect the separated solid particles and the entrained liquid uniformly, and the solid-liquid mixed tail water collected in the filter barrel can be separated again through the filter net. The separated solid particles remain in the filter barrel, and the separated tail water can re-enter the separation pipe body through the outlet pipe 2, so as to realize the circulation filtration and use of the tail water and improve the utilization efficiency of the tail water. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A stereoscopic diagram of the negative pressure curved flow separation tube provided by the present invention.

[0024] Figure 2 This is a schematic structural diagram of the negative pressure curved flow separation tube provided by the present invention at another angle.

[0025] Figure 3 It is a schematic structural diagram of a separation pipe body and a bend pipe of a negative pressure bend flow separation pipe provided by the present invention on a plane where the plane where the bottom surface of the reflux pipe is located is taken as a reference plane.

[0026] Figure 4 This is an enlarged schematic diagram of the structure of the separation tube body provided by the present invention.

[0027] Figure 5 This is an enlarged schematic top view of the negative pressure curved flow separation tube provided by the present invention.

[0028] Figure 6 This is a partial enlarged schematic diagram of the structure of the separation pipe body and the elbow provided by the present invention when they are connected.

[0029] The markings in the figure are: 1. separation tube body; 11. cylindrical cavity; 2. return pipe; 3. elbow; 4. water inlet pipe 1; 5. water outlet pipe 1; 6. filter barrel; 61. water outlet pipe 2. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0031] In the description of the present invention, it should be noted that for directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention. The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "including" and "having" in the specification and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device including a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] This embodiment provides a negative pressure curved flow separation tube, please refer to Figure 1 and Figure 2 , which is installed at the front end of the water inlet of the microfilter, and is used to separate the solid and liquid of the tail water entering the microfilter. The negative pressure curved flow separation pipe includes a separation pipe body 1, a return pipe 2 and a plurality of curved pipes 3. The separation pipe body 1 is a spiral structure, and the spiral structure makes the separation pipe body 1 itself surround a cylindrical cavity 11. The return pipe 2 is installed in the cylindrical cavity 11, the central axis of the return pipe 2 coincides with the central axis of the cylindrical cavity 11, and the outer diameter of the return pipe 2 is smaller than the diameter of the cylindrical cavity 11, so that the return pipe 2 is installed in the cylindrical cavity 11 and does not contact the separation pipe body 1. Multiple curved pipes 3 are installed in the cylindrical cavity 11. One end of each curved pipe 3 is connected to the separation pipe body 1, and the other end of each curved pipe 3 is bent downward and connected to the return pipe 2. The separation pipe body 1 and the return pipe 2 are connected by setting the curved pipe 3. The lower end of the separation tube body 1 is connected to a water inlet pipe 4, and the upper end of the separation tube body 1 is connected to a water outlet pipe 5. The tail water that needs to be filtered in the circulating water system can enter the separation tube body 1 through the water inlet pipe 4, and flow upward along the separation tube body 1, and finally flow into the microfilter from the water outlet pipe 5. The microfilter can perform a second filtration operation on the tail water filtered by the negative pressure curved flow separation tube.

[0033] The negative pressure curved flow separation tube of the present invention can be used to treat tail water with a suspended matter concentration of 200-800 mg / L, and its working flow rate can be 0.2-1.0 m / s.

[0034] The negative pressure curved flow separation tube of the present invention has a separation efficiency of more than 72.3% for impurity particles of 50 μm under the conditions of tail water suspended particle concentration of 500 mg / L and flow rate of 0.5 m / s.

[0035] In this embodiment, please refer to Figure 2 and Figure 3 , set the plane where the bottom surface of the return pipe 2 is located as the reference plane, and the center of the circle where the elbow 3 is connected with the separation pipe is point 1, that is, Figure 3 The center of the return pipe 2 is point 2, that is, Figure 3 The straight line connecting the vertical projections of point 1 and point 2 on the reference plane is line 1, that is, Figure 3 The angle between the vertical projection of the elbow 3 on the reference plane and the straight line OA (i.e. Figure 3 The median angle α) is smaller than the angle between the vertical projection of the elbow 3 on the reference plane and the straight line 1 (i.e. Figure 3 The middle angle β). Through this arrangement, after the tail water enters the separation pipe body 1, the solid-liquid separation is realized by utilizing the difference in the distribution of solids and liquids in the water flow during the turning process. When the tail water enters the separation pipe body 1 from the water inlet pipe 4, since the separation pipe body 1 is a spiral structure, its inner diameter gradually decreases from bottom to top, and the speed of the tail water entering the separation pipe body 1 is very large, which will cause negative pressure to be easily generated in the separation pipe body 1. Under the action of negative pressure, the solid particles in the tail water will approach the inner wall of the separation pipe body 1, and the liquid in the tail water will approach the outer wall of the elbow 3. At the connection between the separation pipe body 1 and the elbow 3, since the solid particles in the tail water are on the side close to the elbow 3, under the action of the rising impact of the tail water and the inertia and gravity of the solid particles during the flow, the solid particles in the tail water will enter the return pipe 2 along the elbow 3, and the liquid in the tail water will rotate and flow upward along the separation pipe body 1, and finally enter the microfilter through the outlet pipe 5, thereby realizing the preliminary filtration operation of the tail water before the tail water enters the microfilter. Since the tail water discharged from the circulating aquaculture system contains a large amount of solid particles such as fish bait and feces, if the tail water containing these solid particles directly enters the microfilter for filtration, this will cause a large load on the microfilter, and the solid particles are easy to clog the microfilter, resulting in poor filtration efficiency and easy damage to the microfilter, resulting in high maintenance costs in the later stage. The present invention provides a negative pressure curved flow separation tube, which is installed at the front end of the water inlet of the microfilter. It can effectively separate the solid and liquid of the tail water through the structure of the negative pressure curved flow separation tube itself, and remove the solid particles in the tail water, thereby avoiding the problem that the solid particles in the tail water easily cause clogging of the microfilter after entering the microfilter, so that the solid particles in the tail water entering the microfilter are greatly reduced, thereby improving the filtration stability of the microfilter and extending the service life of the microfilter.

[0036] In this embodiment, please refer to Figure 4 and Figure 5 The separation tube body 1 can be a spiral structure with equal diameter and equal distance, and it includes multiple spiral coils, which are connected in sequence to form the separation tube body 1. The structure of each spiral coil is the same and the rotation angle of a single spiral coil is 360°. By providing multiple spiral coils, the tail water can rotate and flow upward in the separation tube body 1, thereby utilizing the principle of the difference in the distribution of solids and liquids in the water flow at the bend to achieve the separation operation of solid particles in the tail water. Two bends 3 are provided in each spiral coil, and each spiral coil can be divided into two half spiral coils, one of the bends 3 is located in one of the half spiral coils, and the other bend 3 is located in the other half spiral coil. The two bends 3 in the same spiral coil are centrally symmetrical about the central axis of the return pipe 2. Please refer to Figure 6 , in each half spiral circle, the bend pipe 3 is at the turning point of the half spiral circle, and the bend pipe 3 is set at the turning point of the spiral circle. By utilizing the difference in the distribution of solids and liquids in the water flow during the turning process, the solid particles in the tail water can enter the bend pipe 3 at the turning point of the spiral circle, and then enter the return pipe 2 through the bend pipe 3, while the liquid in the tail water will continue to flow downward along the spiral circle, thereby realizing the solid-liquid separation operation of the tail water. It can be understood that in this embodiment, there is a turning point on each half spiral circle, and by arranging the bend pipe 3 at the turning point, during the solid-liquid separation process, the principle of the difference in the distribution of solids and liquids in the tail water at the turning point of the spiral structure of the separation tube body 1 can be well utilized to realize the solid-liquid separation of the tail water. By arranging two elbows 3 in one spiral circle, and both elbows 3 process the turning point of each half spiral circle, the turning point can be understood as the place where the flow direction of the water flow changes the most in the half spiral circle, and the negative pressure generated by the tail water is the largest at this place, so the solid particles in the tail water will enter the return pipe 2 through the elbow 3, and the liquid in the tail water will continue to rotate and flow upward along with the separation tube body 1. As a result, the separation tube body 1 in this embodiment can effectively separate the solid particles in the tail water and improve its separation effect.

[0037] Understandably, please refer to Figure 2 and Figure 6 In each half spiral, the elbow 3 is located at the lowest point of the turn of the half spiral. By arranging the elbow 3 at the lowest point of the turn, the solid particles in the tail water separated at the turn can all enter the elbow 3 under the action of inertia and gravity, thereby further improving the effect of solid-liquid separation in the tail water.

[0038] In other embodiments, three curved pipes 3 may be arranged in each spiral turn, and the connection angle between the curved pipe 3 and the return pipe 2 is 45° to 70°.

[0039] The ratio of the length of the separation tube body 1 in the axial direction to the inner diameter of the separation tube body 1 is 5:1 to 10:1. It can be understood that the inner diameter of the separation tube body 1 here refers to the maximum inner diameter of the separation tube body 1. Since the inner diameter of the separation tube body 1 gradually decreases from bottom to top, the maximum inner diameter of the separation tube body 1 should be located at the inner diameter of the connection with the water inlet pipe 4, and the minimum inner diameter of the separation tube body 1 is the inner diameter of the connection with the outlet pipe 5. In this embodiment, the tail water in the circulating aquaculture system can be transported to the water inlet pipe 4 by a water pump, and then enter the separation tube body 1 through the water inlet pipe 4, and move upward with the separation tube body 1 to the outlet pipe 5, and finally flow out from the outlet pipe 5 to the microfilter. By limiting the ratio of the length of the separation tube body 1 in the axial direction and the inner diameter of the separation tube body 1, the tail water can flow upward along the separation tube body 1 under a relatively small driving force while ensuring that a negative pressure is generated in the separation tube body 1, so that the solid and liquid in the tail water entering the separation tube body 1 can be effectively separated at the turning point, thereby achieving a greater degree of solid-liquid separation in the separation tube body 1 in the tail water while satisfying a relatively small driving force, thereby saving separation costs while also improving separation efficiency.

[0040] The helical angle of the separation tube body 1 can be 30°-60°.

[0041] The separation tube body 1 can be an equal diameter and equal distance spiral structure. It can be understood that in this embodiment, equal diameter means that the vertical distances from each point on each spiral circle to the central axis of the cylindrical cavity 11 are equal, and equal distance means that the pitch of each spiral circle of the separation tube body 1 is the same. By setting it as an equal diameter and equal distance spiral structure, the stability of water flow in the separation tube body 1 can be effectively improved. In addition, for the inner diameter of the separation tube body 1, its inner diameter decreases from bottom to top, and the reduction ratio is 2%-5% for every 100mm of the inner diameter of the separation tube body 1 along the vertical direction.

[0042] The inner diameter of the bend 3 is one quarter to one half of the inner diameter of the separation tube body 1. It can be understood that the inner diameter of the separation tube body 1 here can be the inner diameter of the separation tube body 1 at the connection between the separation tube body 1 and the bend 3. Therefore, in the actual operation process, the inner diameter of each bend 3 is actually different. The inner diameter of the bend 3 installed at the lower end of the separation tube body 1 is the largest, and the inner diameter of the bend 3 installed at the upper end of the separation tube body 1 is the smallest. The above setting is to correspond to the gradual decrease of the inner diameter of the separation tube body 1 from bottom to top. The ratio of the inner diameter of the separation tube body 1 at the connection between the separation tube body 1 and the bend 3 to the inner diameter of the bend 3 is between one quarter and one half. At the same time, by setting this ratio, most of the solid particles in the tail water at the bend of the separation tube body 1 can enter the bend 3 under the action of inertia and gravity, thereby improving the solid-liquid separation effect of the entire negative pressure bend flow separation tube.

[0043] The filter barrel 6 is connected to the lower part of the return pipe 2, and the filter barrel 6 is rotatably connected to the return pipe 2. Figure 1 In this embodiment, the filter barrel 6 can be connected to the lower end of the return pipe 2 by a threaded connection, and the threaded connection is very simple to install and disassemble. A plurality of filter screens are arranged in the filter barrel 6, and the plurality of filter screens are used to separate the solid-liquid mixed tail water entering the return pipe 2. It can be understood that in this embodiment, the separation tube body 1 can realize solid-liquid separation by utilizing the difference in the distribution of solids and liquids at the bend of the water flow. In this process, as the solid particles enter the elbow 3, it is inevitable that a small part of the liquid will enter the return pipe 2 along with the solid particles. Therefore, in this embodiment, a filter barrel 6 is arranged below the return pipe 2, and the filter barrel 6 can collect the separated solid particles and the entrained liquid uniformly, and the solid-liquid mixed tail water collected in the filter barrel 6 can be separated again through the filter screen. A water outlet pipe 2 61 is arranged on the filter barrel 6, and the water outlet pipe 2 61 is connected to the water inlet pipe 1 4. The tail water filtered by the filter barrel 6 can enter the water inlet pipe 1 4 along the water outlet pipe 2 61. The water inlet pipe 14 can be a three-way pipe, one of the pipe openings of the water inlet pipe 14 is connected to the water outlet pipe 2 61 of the filter barrel 6 through a pipe, the second pipe opening of the water inlet pipe 14 can be connected to the water outlet pipe 3 of the tail water in the circulating aquaculture system through a pipe, and the third pipe opening of the water inlet pipe 14 is connected to the lower end of the separation pipe body 1. In actual operation, the tail water generated in the circulating aquaculture system can enter the separation pipe body 1 through the water outlet pipe 3 and the second pipe opening of the water inlet pipe 14, and the separation pipe body 1 can perform solid-liquid separation on the entering tail water, and most of the separated liquid continues to flow upward along with the separation pipe body 1. Most of the separated solid particles and a small part of the mixed liquid enter the return pipe 2 through the bend pipe 3, and this part of the solid-liquid mixed tail water can be filtered for the second time through the filter barrel 6, and the solid particles in the tail water after the second filtration remain in the filter barrel 6, and the liquid can be refluxed from the water outlet pipe 2 61 to the water inlet pipe 14 through the water pump, so as to enter the separation pipe body 1 again for solid-liquid separation.

[0044] It is understandable that a water outlet pipe 3 may also be provided on the filter barrel 6, and the water outlet pipe 3 may be directly connected to the microfilter. The water outlet pipe 3 may directly pump the filtered liquid in the filter barrel 6 into the microfilter through a water pump for filtration.

[0045] In actual application, if the content of solid particles in the tail water after filtering by the filter barrel 6 is still high, the valve between the outlet pipe 2 61 and the inlet pipe 1 4 is opened at this time, so that the tail water filtered by the filter barrel 6 can be circulated and filtered again through the separation tube body 1. If the content of solid particles in the tail water after filtering by the filter barrel 6 is low, the valve between the outlet pipe 3 and the microfilter can be directly opened, so that the tail water filtered by the filter barrel 6 can be directly pumped into the microfilter through the water pump for secondary filtration.

[0046] The solid particle content of the tail water after filtering in the filter barrel 6 can be detected by existing technical means. If the detected solid particle content reaches the standard that can be directly pumped into the microfilter, the valve between the outlet pipe 2 61 and the inlet pipe 1 4 is opened, so that the tail water filtered through the filter barrel 6 can be circulated and filtered again through the separation tube body 1. If the detected solid particle content does not reach the standard that can be directly pumped into the microfilter, the valve between the outlet pipe 3 and the microfilter is opened, so that the tail water filtered through the filter barrel 6 can be directly pumped into the microfilter through the water pump for secondary filtration.

[0047] It is understandable that the standard for the tail water to be directly pumped into the microfilter can be set according to the models of different microfilters, and the standard can be defined as the solid particle concentration in the pumped tail water being less than 50 mg / L. Because the solid particle concentration is too high, it is easy to cause the microfilter to be blocked and affect its filtering effect. Therefore, in this embodiment, by setting this standard, the concentration of solid particles in the tail water entering the microfilter is low, so that the microfilter will not be damaged due to solid particle blockage when filtering the tail water, which greatly improves the filtering effect of the microfilter, and also extends the service life of the microfilter, so that it will not be damaged due to blockage, reducing its maintenance cost.

[0048] In addition, a one-way valve is provided on the outlet pipe 2 61, which allows the tail water between the filter barrel 6 and the inlet pipe 1 4 to flow only from the outlet pipe 2 61 of the filter barrel 6 to the inlet pipe 1 4. By providing the one-way valve, the tail water in the inlet pipe 1 4 can only enter the separation pipe body 1 along the third pipe opening, and will not flow back into the filter barrel 6.

[0049] It can be understood that in the present embodiment, a water collecting tank may be further provided between the negative pressure curved flow separation pipe and the microfilter, the outlet pipe 61 is also a three-way pipe, the first pipe opening of the outlet pipe 61 is directly connected to the separation pipe body 1, the second pipe opening of the outlet pipe 61 is connected to the microfilter, and the third pipe opening of the outlet pipe 61 is connected to the water collecting tank. When the content of solid particles in the tail water after the tail water passes through the separation pipe body 1 once and is greater than 50 mg / L, the tail water separated by the separation pipe body 1 can enter the water collecting tank through the outlet pipe 61 and the third pipe opening, and the water entering the water collecting tank can be pumped into the inlet pipe 4 again by a water pump, so that the tail water can pass through the separation pipe body 1 for a secondary solid-liquid separation operation, and the above operation is performed until the content of solid particles in the tail water separated by the separation pipe body 1 is lower than 50 mg / L, at which time the tail water after solid-liquid separation can be directly transported to the filter for filtration. By setting up a water collection tank, it is possible to effectively avoid the problem that the solid particle content in the tail water after solid-liquid separation by the separation tube body 1 is still very high and causes clogging of the microfilter, thereby achieving the purpose of protecting the microfilter. The present invention can effectively perform preliminary solid-liquid separation operations on the tail water before entering the microfilter by setting up the above-mentioned negative pressure curved flow separation tube at the water inlet of the microfilter, so that the solid particle content of the tail water entering the microfilter is low, and the microfilter is not easily clogged when filtering the tail water, thereby improving the service life of the microfilter and the stability of the movement of the entire circulating aquaculture system. In addition, the negative pressure curved flow separation tube in the present invention has a compact structure, a small footprint, a high space utilization rate, and a good separation effect.

[0050] The above describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention to be protected. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A negative pressure curved flow separation tube, characterized in that: It is installed at the front end of the water inlet of the microfilter and is used to separate the solid and liquid of the tail water entering the microfilter; the negative pressure curved flow separation pipe includes: The separation tube body (1) has a spiral structure, and the spiral structure enables the separation tube body (1) to surround a cylindrical cavity (11); the lower end of the separation tube body (1) is connected to a water inlet pipe (4), and the upper end of the separation tube body (1) is connected to a water outlet pipe (5); the inner diameter of the separation tube body (1) gradually decreases from bottom to top; A return pipe (2) is installed in the cylindrical cavity (11), the central axis of the return pipe (2) coincides with the central axis of the cylindrical cavity (11), and the outer diameter of the return pipe (2) is smaller than the diameter of the cylindrical cavity (11); and a plurality of bent pipes (3), wherein the plurality of bent pipes (3) are installed in the cylindrical cavity (11); one end of the bent pipe (3) is connected to the separation pipe body (1), and the other end of the bent pipe (3) is bent downward and connected to the return pipe (2); The plane where the bottom surface of the return pipe (2) is located is set as the reference plane, the center of the connection between the bent pipe (3) and the separation pipe body (1) is point 1, the center of the return pipe (2) is point 2, and the straight line formed by the vertical projections of point 1 and point 2 on the reference plane is straight line 1; the angle between the vertical projection of the bent pipe (3) on the reference plane and straight line 1 is smaller than the angle between the vertical projection of the bent pipe (3) on the reference plane and straight line 1; The tail water to be filtered enters from the water inlet pipe 1 (4) at the lower end of the separation pipe body (1), and flows upward in a rotational manner along the separation pipe body (1) until entering the microfiltration machine from the water outlet pipe 1 (5); at the connection between the separation pipe body (1) and the bend pipe (3), the solid particles in the tail water flow along the bend pipe (3) on the inner side of the separation pipe body (1) to the return pipe (2), and the liquid in the tail water flows upward in a rotational manner along the separation pipe body (1).

2. The negative pressure curved flow separation tube according to claim 1, characterized in that: The ratio of the length of the separation tube body (1) in the axial direction to the inner diameter of the separation tube body (1) is 5:1 to 10:

1.

3. The negative pressure curved flow separation tube according to claim 1, characterized in that: The separation tube body (1) comprises a plurality of spiral turns, each of which is provided with two curved pipes (3), each of which is divided into two half spiral turns, the two curved pipes (3) are respectively arranged in the two half spiral turns, and the two curved pipes (3) in the same spiral turn are centrally symmetrical about the central axis of the return pipe (2).

4. The negative pressure curved flow separation tube according to claim 3, characterized in that: In the semi-helical circle, the curved pipe (3) is located at the lowest point of the turning point of the semi-helical circle.

5. The negative pressure curved flow separation tube according to claim 1, characterized in that: The separation tube body (1) comprises a plurality of spiral coils, each of which is provided with three curved pipes (3), and the connection angle between the curved pipes (3) and the return pipe (2) is 45°-70°.

6. The negative pressure curved flow separation tube according to claim 1, characterized in that: A filter barrel (6) is connected below the reflux pipe (2), and the filter barrel (6) is rotatably connected to the reflux pipe (2). A plurality of filter screens are arranged inside the filter barrel (6), and the plurality of filter screens are used to separate the solid-liquid mixed tail water entering the reflux pipe (2).

7. The negative pressure curved flow separation tube according to claim 1, characterized in that: The water inlet pipe 1 (4) is a three-way pipe; And / or, the water outlet pipe 1 (5) is a three-way pipe.

8. The negative pressure curved flow separation tube according to claim 1, characterized in that: The inner diameter of the curved pipe (3) is one quarter to one half of the inner diameter of the separation pipe body (1); And / or, the separation tube body (1) is an equal-diameter and equal-distance spiral structure, the spiral angle of the separation tube body (1) is 30°-60°, and the inner diameter of the separation tube body (1) gradually decreases from bottom to top, and the reduction ratio is 2%-5% for every 100 mm in the vertical direction.

9. The negative pressure curved flow separation tube according to claim 6, characterized in that: The filter barrel (6) is provided with a second water outlet pipe (61), the second water outlet pipe (61) being connected to the first water inlet pipe (4), and the tail water filtered by the filter barrel (6) enters the first water inlet pipe (4) along the second water outlet pipe (61).

10. The negative pressure curved flow separation tube according to claim 9, characterized in that: The second water outlet pipe (61) is provided with a one-way valve, and the one-way valve allows the water between the filter barrel (6) and the first water inlet pipe (4) to flow only from the second water outlet pipe (61) of the filter barrel (6) to the first water inlet pipe (4).

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