A negative pressure bend flow separation tube

Abstract

The present invention belongs to the field of circulating aquaculture equipment, and specifically relates to a negative pressure curved flow separation pipe. The negative pressure curved flow separation pipe is installed at the front end of the water inlet of the microfiltration machine, and includes a separation pipe body, a return pipe and a plurality of bends. The separation pipe body has a spiral structure. The separation pipe body is provided with a cylindrical cavity, and the return pipe is installed in the cylindrical cavity. One end of the bend is connected to the separation pipe body, and the other end is bent downward and connected to the return pipe. The tail water entering the separation pipe body will flow upward along the separation pipe body in a rotating manner. At the connection between the separation pipe body and the bend, the principle of the difference in the distribution of solids and liquids during the turning process of the water flow is utilized, so that the solid particles will flow along the bend inside the separation pipe body to the return pipe, and the liquid will flow upward along the separation pipe body in a rotating manner. In this way, the solid-liquid separation of the tail water is achieved, and the problem of solid particles in the tail water easily clogging the microfiltration machine after entering the microfiltration machine is avoided, thereby improving the filtration stability of the microfiltration machine.

Description

Technical Field

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

[0002] The recirculating aquaculture system is a new type of aquaculture model that uses a series of water treatment units to treat wastewater generated in the aquaculture ponds and then recycle it for reuse. The main principle of the recirculating aquaculture system is to integrate advanced technologies from disciplines such as environmental engineering, civil engineering, modern biology, and electronic information. The system aims to remove harmful pollutants such as residual bait and feces, ammonia nitrogen, and nitrite nitrogen from the aquaculture water, thereby purifying the aquaculture environment. The system uses physical filtration, biological filtration, CO2 removal, disinfection, oxygenation, and temperature control to return the purified water to the aquaculture pond. It not only solves the problem of low water resource utilization, but also provides a stable, reliable, and comfortable living environment for aquaculture organisms, providing favorable conditions for high-density aquaculture.

[0003] In existing recirculating aquaculture systems, microfiltration machines are generally used to filter the tail water from aquaculture. However, the tail water generally contains a large amount of fish bait and feces. These solid particles will cause clogging of the microfiltration machine, thereby greatly reducing the filtration efficiency of the microfiltration machine. Summary of the Invention

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

[0005] The present invention is implemented by the following technical solutions: a negative pressure curved flow separation pipe, which is installed at the front end of the water inlet of the microfiltration machine and is used for solid-liquid separation of tail water entering the microfiltration machine; 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 form 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 the curved pipes are all 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 on which the bottom surface of the return pipe lies is set as the reference plane, the center of the connection between the elbow 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 line 1; the angle between the vertical projection of the elbow on the reference plane and line 1 is smaller than the angle between the vertical projection of the elbow on the reference plane and 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 and flows upward along the separation tube body until it enters 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 and flow 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, and 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 bent 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 return pipe, and the filter barrel is rotatably connected to the return pipe. A plurality of filter screens are provided in the filter barrel, and the plurality of filter screens are used to separate the solid-liquid mixed tail water entering the return 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 first water outlet pipe 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 100 mm in the vertical direction.

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

[0018] As a further improvement of the present invention, a one-way valve is provided on the water outlet pipe 2, which 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. 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 utilized, so that the solid particles in the tail water will gather on the side close to the curved pipe, and the liquid in the tail water will 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 prone to clogging the microfilter after entering the microfilter, and greatly reducing the solid particles in the tail water entering the microfilter, 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 disposed below the return pipe. The filter barrel can collect the separated solid particles and the entrained liquid in a unified manner. The solid-liquid mixed tail water collected in the filter barrel can be separated again through a filter screen. 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, thereby realizing the recycling filtration and use of the tail water and improving the utilization efficiency of the tail water. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A three-dimensional 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 This is a structural schematic diagram of the separation pipe body and the bend pipe of the negative pressure bend flow separation pipe provided by the present invention, with the plane where the bottom surface of the return pipe is located as the 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 top view of the negative pressure curved flow separation tube provided by the present invention.

[0028] Figure 6 This is an enlarged schematic diagram of part of the structure when the separation pipe body and the elbow provided by the present invention 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 tank; 61. water outlet pipe 2. DETAILED DESCRIPTION

[0030] The present invention will be 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 new embodiments.

[0031] In the description of the present invention, it should be noted that for directional words, such as the terms "center", "transverse", "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 accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and should not be understood as limiting the specific scope of protection of the present invention. The terms "first", "second", etc. in the description 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" and any variations thereof in the description and claims of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0032] This embodiment provides a negative pressure bend flow separation tube, please refer to Figure 1 and Figure 2 , which is installed at the front end of the water inlet of the microfiltration machine, and is used to separate the solid and liquid of the tail water entering the microfiltration machine. 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, and 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 separator body 1 is connected to an inlet pipe 4, and the upper end is connected to an outlet pipe 5. Tailwater from the circulating water system that needs to be filtered enters the separator body 1 through the inlet pipe 4, flows upward along the separator body 1, and finally flows through the outlet pipe 5 into the microfilter. The microfilter can refilter the tailwater after it has been filtered through the negative pressure bend separator.

[0033] The negative pressure curved flow separation tube of the present invention can be applied to treating 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 velocity 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 At point A, the center of the return pipe 2 is point 2, that is, Figure 3 The straight line connecting the vertical projections of point O, 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 angle β is defined as the median angle. This arrangement allows for solid-liquid separation after the tailwater enters the separation tube body 1 by utilizing the differences in the distribution of solids and liquids during the bend. When the tailwater enters the separation tube body 1 from the inlet pipe 4, due to the spiral structure of the separation tube body 1, its inner diameter gradually decreases from bottom to top. Furthermore, the tailwater enters the separation tube body 1 at a high velocity, which easily generates a negative pressure within the separation tube body 1. Under this negative pressure, solid particles in the tailwater approach the inner wall of the separation tube body 1, while liquid in the tailwater approaches the outer wall of the bend 3. At the junction of the separation tube body 1 and the bend 3, solid particles in the tailwater are located on the side closest to the bend 3. Due to the upward momentum of the tailwater, the inertia of the solid particles during flow, and gravity, the solid particles in the tailwater flow along the bend 3 and into the return pipe 2. The liquid in the tailwater continues to rotate upward along the separation tube body 1, ultimately entering the microfiltration unit through the outlet pipe 5. This achieves a preliminary filtration of the tailwater before it enters the microfiltration unit. Since the tail water discharged from the recirculating 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 microfiltration machine for filtration, this will cause a large load on the microfiltration machine, and the solid particles are easy to clog the microfiltration machine, resulting in poor filtration efficiency and easy damage to the microfiltration machine, making the subsequent maintenance cost high. The present invention provides a negative pressure bend flow separation tube, which is installed at the front end of the water inlet of the microfiltration machine. It can effectively achieve solid-liquid separation of the tail water through the structure of the negative pressure bend flow separation tube itself, and remove the solid particles in the tail water, thereby avoiding the problem of solid particles in the tail water easily clogging the microfiltration machine after entering the microfiltration machine, so that the solid particles in the tail water entering the microfiltration machine are greatly reduced, thereby improving the filtration stability of the microfiltration machine and extending the service life of the microfiltration machine.

[0036] In this embodiment, please refer to Figure 4 and Figure 5 , the separation tube body 1 can be a spiral structure of 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 setting up 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 solid and liquid distribution at the turning point of the water flow to achieve the separation operation of solid particles in the tail water. There are two bends 3 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 turn, the bend 3 is located at the turning point of the half spiral turn. By arranging the bend 3 at the turning point of the spiral turn, the difference in solid and liquid distribution during the turning process of the water flow is utilized, so that solid particles in the tail water can enter the bend 3 at the turning point of the spiral turn, and then enter the return pipe 2 through the bend 3, while the liquid in the tail water will continue to flow downward along the spiral turn, thereby achieving a solid-liquid separation operation for the tail water. It can be understood that in this embodiment, there is a turning point on each half spiral turn. By arranging the bend 3 at the turning point, the solid-liquid separation operation of the tail water can be effectively achieved by utilizing the principle of the difference in solid and liquid distribution of the tail water at the turning point of the spiral structure of the separation tube body 1. By providing two elbows 3 within a spiral turn, and both elbows 3 process the turning point of each half spiral turn, the turning point can be understood as the place where the flow direction of the water changes the most within the half spiral turn. At this point, the negative pressure generated by the tail water is the largest. Therefore, 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 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, improving its separation effect.

[0037] Understandably, please refer to Figure 2 and Figure 6 In each half-helical turn, the elbow 3 is located at the lowest point of the turn. By placing 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 solid-liquid separation effect in the tail water.

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

[0039] The ratio of the axial length of the separation tube body 1 to the inner diameter of the separation tube body 1 is 5:1 to 10:1. It should be understood that the inner diameter of the separation tube body 1 herein 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 at the connection with the water inlet pipe 4, and the minimum inner diameter of the separation tube body 1 should be located at the inner diameter at the connection with the water outlet pipe 5. In this embodiment, the tail water in the recirculating aquaculture system can be pumped to the water inlet pipe 4, then enter the separation tube body 1 through the water inlet pipe 4, and move upward along the separation tube body 1 to the water outlet pipe 5, and finally flow out of the water outlet pipe 5 into the microfiltration machine. 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 smaller driving force while ensuring that a negative pressure is generated in the separation tube body 1, so that the solids and liquids 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 smaller 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 have an equal-diameter and equal-pitch spiral structure. It should be understood that in this embodiment, equal-diameter refers to the vertical distance from each point on each spiral turn to the central axis of the cylindrical cavity 11 being equal, while equal-pitch refers to the fact that the pitch of each spiral turn of the separation tube body 1 is the same. This equal-diameter and equal-pitch spiral structure effectively improves the stability of water flow within the separation tube body 1. Furthermore, the inner diameter of the separation tube body 1 decreases from bottom to top, with a reduction ratio of 2%-5% for every 100 mm 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 actual operation, 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 in 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 connected to the return pipe 2 by rotation. Figure 1 In this embodiment, the filter barrel 6 can be connected to the lower end of the return pipe 2 by means of a threaded connection, which is easy to install and remove. Multiple filter screens are provided in the filter barrel 6, which 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 achieve solid-liquid separation by utilizing the difference in solid and liquid distribution at the bend of the water flow. In this process, as solid particles enter the bend 3, a small amount of liquid will inevitably enter the return pipe 2 along with the solid particles. Therefore, in this embodiment, a filter barrel 6 is provided below the return pipe 2. The filter barrel 6 can collect the separated solid particles and the entrained liquid in a unified manner, and the solid-liquid mixed tail water collected in the filter barrel 6 can be separated again through the filter screen. The filter barrel 6 is provided with an outlet pipe 2 61, which is connected to the inlet pipe 1 4. The tail water filtered by the filter barrel 6 can enter the inlet pipe 1 4 along the outlet pipe 2 61. Inlet pipe 1 (4) can be a tee pipe. One of its openings is connected to outlet pipe 2 (61) of filter barrel 6 via a pipe. The second opening of inlet pipe 1 (4) is connected to outlet pipe 3 of the recirculating aquaculture system's tailwater via a pipe. The third opening of inlet pipe 1 (4) is connected to the lower end of separation pipe body 1. In actual operation, tailwater generated in the recirculating aquaculture system can enter separation pipe body 1 through outlet pipe 3 and the second opening of inlet pipe 1 (4). Separation pipe body 1 performs solid-liquid separation on the incoming tailwater, with the majority of the separated liquid continuing to flow upward along separation pipe body 1. Most of the separated solid particles and a small amount of mixed liquid enter return pipe 2 through elbow pipe 3. This mixed solid-liquid tailwater can then undergo a secondary filtration through filter barrel 6. The solid particles in the secondary filtered tailwater remain in filter barrel 6, and the liquid can be pumped back from outlet pipe 2 (61) to inlet pipe 1 (4), where it can then re-enter separation into separation pipe body 1 for solid-liquid separation.

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

[0045] In actual application, if the content of solid particles in the tail water after filtering 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 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 microfiltration machine, the valve between the outlet pipe 2 61 and the inlet pipe 1 4 is opened, 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 detected solid particle content does not reach the standard that can be directly pumped into the microfiltration machine, the valve between the outlet pipe 3 and the microfiltration machine is opened, so that the tail water filtered by the filter barrel 6 can be directly pumped into the microfiltration machine 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. The standard can be defined as the solid particle concentration in the pumped tail water being lower than 50 mg / L. Because when the solid particle concentration is too high, it is easy to cause the microfilter to be clogged 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 by solid particle clogging when filtering the tail water, which greatly improves the filtering effect of the microfilter. At the same time, it also extends the service life of the microfilter so that it will not be damaged by clogging and reduces its maintenance cost.

[0048] In addition, a one-way valve is installed on the second outlet pipe 61. This valve prevents the tail water from flowing between the filter barrel 6 and the first inlet pipe 4 from flowing only from the second outlet pipe 61 of the filter barrel 6 to the first inlet pipe 4. By installing the one-way valve, the tail water in the first inlet pipe 4 will only enter the separation pipe body 1 through the third pipe opening and will not flow back into the filter barrel 6.

[0049] It can be understood that in this embodiment, a water collection tank can be provided between the negative pressure bend flow separation pipe and the microfilter, and the outlet pipe 2 61 is also a three-way pipe. The first pipe mouth of the outlet pipe 2 61 is directly connected to the separation pipe body 1, the second pipe mouth of the outlet pipe 2 61 is connected to the microfilter, and the third pipe mouth of the outlet pipe 2 61 is connected to the water collection tank. When the content of solid particles in the tail water after the tail water passes through the separation pipe body 1 is greater than 50 mg / L, the tail water separated by the separation pipe body 1 can enter the water collection tank through the outlet pipe 2 61 and the third pipe mouth. The water entering the water collection tank can be pumped into the water inlet pipe 1 4 again by a water pump, so that the tail water can undergo a secondary solid-liquid separation operation through the separation pipe body 1. The above operation is performed until the content of solid particles in the tail water after separation by the separation pipe body 1 is lower than 50 mg / L. At this time, the tail water after solid-liquid separation can be directly transported to the filter for filtration. By providing a water collection tank, the problem of the tail water after solid-liquid separation by the separation tube body 1 still having a high solid particle content, which may cause clogging of the microfiltration machine, can be effectively avoided, thereby achieving the purpose of protecting the microfiltration machine. The present invention provides a negative pressure bend flow separation tube as described above at the water inlet of the microfiltration machine, which can effectively perform a preliminary solid-liquid separation operation on the tail water before entering the microfiltration machine, so that the solid particle content of the tail water entering the microfiltration machine is low, making the microfiltration machine less likely to be clogged when filtering the tail water, thereby increasing the service life of the microfiltration machine and improving the stability of the movement of the entire recirculating aquaculture system. In addition, the negative pressure bend flow separation tube of the present invention has a compact structure, a small footprint, high space utilization, and 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 foregoing embodiments. The foregoing embodiments and description merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A negative pressure bend separation tube, characterized in that: It is installed at the front end of the water inlet of the microfiltration machine and is used to separate the solid and liquid of the tail water entering the microfiltration machine; the negative pressure bend separation pipe includes: The separation tube body (1) has a spiral structure, and the spiral structure enables the separation tube body (1) to enclose 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) installed in the cylindrical cavity (11), wherein 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 curved pipes (3), each of the curved pipes (3) being installed in the cylindrical cavity (11); one end of the curved pipe (3) being connected to the separation pipe body (1), and the other end of the curved pipe (3) being 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 circle of the bend pipe (3) at the connection with the separation pipe body (1) is point 1, the center of the circle 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 bend pipe (3) on the reference plane and straight line 1 is smaller than the angle between the vertical projection of the bend 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 in a rotational manner upward 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), solid particles in the tail water flow along the bend pipe (3) inside the separation pipe body (1) to the return pipe (2), and liquid in the tail water flows in a rotational manner upward 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) being respectively provided 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 bends (3), and the connection angle between the bends (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 return pipe (2), and the filter barrel (6) is rotatably connected to the return pipe (2). A plurality of filter screens are provided 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).

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 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), which is connected to the first water inlet pipe (4). 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: A one-way valve is provided on the second water outlet pipe (61), 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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