Large cannon barrel aerator and energy-saving oxygenation method of large cannon barrel aerator

Abstract

The present invention is applicable to the field of water body oxygenation, and provides a cannon barrel aerator and a method for energy-saving oxygenation of a cannon barrel aerator. The cannon barrel aerator includes: an air pump, an aeration pipe, and a connecting pipe. The air pump drives air to enter the aeration pipe through the connecting pipe and enter the water body through the aeration pipe. The cannon barrel aerator also includes: a plug flow pump, the plug flow pump has a cylindrical shell and a spiral impeller is arranged in the cylindrical shell; a transfer pipe, which is used to connect the connecting pipe and the aeration pipe, and the transfer pipe passes through the cylindrical shell and is fixed behind the spiral impeller; a large water pipe, which is connected to the rear end of the cylindrical shell and extends backward; wherein the aeration pipe is fixed to the connecting terminal of the transfer pipe and is located in the large water pipe and extends backward. The cannon barrel aerator provided by the present invention has significant improvements in energy saving and consumption reduction and oxygenation effect compared with the existing oxygenation equipment in the field.

Description

Technical Field

[0001] The invention belongs to the technical field of water body oxygenation, and in particular relates to a large cannon barrel aerator and an energy-saving oxygenation method of the large cannon barrel aerator. Background Art

[0002] Aerators are widely used in aquaculture. Their function is to increase the oxygen content in water and improve water quality. They are a key tool for stabilizing and increasing production in aquaculture. From the current situation of aerators, the aerators that have been produced on a large scale have low technical content and general oxygenation effects. In particular, the high energy consumption of aerators has always been a pain in the hearts of aquaculture farmers. On the other hand, some aerators indirectly increase oxygen by improving water quality. Improper use will not only fail to increase oxygen, but will cause water oxygenation. The most representative one is the surge aerator. Among farmers, the "three-on and two-off" aerator startup method is even more popular, that is, "three-on" means that the aerator can be turned on at noon on a sunny day, if it is cloudy, it will be turned on in the morning of the next day, and if it is rainy, it will be turned on at midnight. "Two-off" means that the aerator should not be turned on in the evening, and it should not be turned on at noon on rainy days. It can be seen that the existing aerator has a general oxygenation effect.

[0003] In terms of energy saving, most manufacturers have only made minor improvements and launched aerators powered by variable frequency motors, but the energy saving is limited and the rated power is usually above 1.5KW. In recent years, my country's aquaculture industry has developed in the direction of high density and intensiveness, and the total amount of aquaculture is huge and growing rapidly. Under this background, there is an urgent need for an aerator that is efficient in oxygenation, energy-saving, simple to use and easy to maintain. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of high energy consumption and low oxygenation effect in existing oxygenation equipment, and to invent a large barrel oxygenator and a method for energy-saving oxygenation of the large barrel oxygenator.

[0005] The present invention provides a cannon barrel aerator, comprising: an air pump, an aeration pipe, and a connecting pipe, wherein the air pump drives air to enter the aeration pipe through the connecting pipe and then enter the water body through the aeration pipe, and the cannon barrel aerator also comprises:

[0006] A plug flow pump, the plug flow pump comprising a cylindrical housing and a spiral impeller arranged in the cylindrical housing;

[0007] A transfer pipe, used to connect the connecting pipe and the aeration pipe, the transfer pipe passes through the cylindrical housing and is fixed behind the spiral impeller;

[0008] A large water pipe connected to the rear end of the cylindrical shell and extending backward;

[0009] Wherein, the aeration pipe is fixed to the connecting terminal of the adapter pipe and is located inside the large water pipe and extends backward.

[0010] Furthermore, the large barrel aerator also includes an electric motor and a speed reduction and speed change mechanism. The electric motor is a double-axle extension electric motor and drives the air pump and the speed reduction and speed change mechanism at the same time. The output shaft of the speed reduction and speed change mechanism is fixedly connected to the spiral impeller.

[0011] Furthermore, the spiral impeller includes a hub and a single blade fixed on the hub, the pitch ratio of the spiral impeller is in the range of [0.5, 1], and the pitch ratio is the ratio of the axial length of the leading edge of the blade along the spiral line of the blade to the diameter of the spiral impeller.

[0012] Furthermore, the spiral impeller includes a hub and a single blade fixed on the hub, the pitch ratio of the spiral impeller is in the range of [0.5, 0.75], and the pitch ratio is the ratio of the axial length of the leading edge of the blade along the spiral line of the spiral impeller to the diameter of the spiral impeller.

[0013] Furthermore, the axial projection area of ​​the blade is equal to the disk area, and the disk area is the axial projection area of ​​the region covered by the rotation of the blade.

[0014] Furthermore, the oxygen enrichment equipment also includes a watertight compartment, the electric motor and the air pump are fixed in the watertight compartment, the speed reduction and speed change mechanism is fixed in the watertight compartment and its output shaft passes through the watertight compartment and is connected to the impeller shaft.

[0015] Furthermore, the plug flow pump also includes a water filter grid, the front end of which is connected to the watertight compartment and the rear end of which is connected to the cylindrical shell, and the water enters the cylindrical shell through the water filter grid.

[0016] The present invention also provides a method for energy-saving oxygenation of a large barrel aerator, comprising the following steps:

[0017] The plug flow pump has a cylindrical housing and a spiral impeller, and the spiral impeller rotates at less than 200 rpm to push water backward to form a water flow;

[0018] A large water pipe is connected to the rear end of the cylindrical shell and extends along the direction of the water flow, and the large water pipe guides the water flow to move backward and spreads it to the surroundings at the water outlet of the large water pipe;

[0019] An aeration pipe is placed in the large water pipe, the aeration pipe extends along the direction of water flow, and the aeration pipe inputs air into the water flow in the large water pipe;

[0020] The water flow velocity in the large water pipe is controlled to be less than 1 m / s, and the volume ratio of the air flow of the aeration pipe to the water flow of the large water pipe is less than 1:5.

[0021] The large barrel aerator provided by the present invention has significant improvements in energy saving and consumption reduction as well as oxygenation effect compared with the existing oxygenation equipment in the field. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other implementation plans can be obtained based on these drawings without paying creative work.

[0023] Figure 1 1 is a schematic diagram of the structure of a cannon barrel aerator according to an embodiment of the present invention, wherein the cylindrical shell is partially visualized;

[0024] Figure 2 It is a partial structural diagram of a large barrel aerator according to an embodiment of the present invention, in which the area where the motor, the speed reduction and speed change mechanism and the air pump are located is visualized;

[0025] Figure 3 It is a schematic diagram of the spiral impeller and matching parts of the large barrel aerator according to an embodiment of the present invention.

[0026] Description of Figure Numbers:

[0027]

[0028] DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0031] It should also be noted that the directional terms such as left, right, up and down in the embodiments of the present invention are merely relative concepts or are based on the normal use status of the product and should not be considered as restrictive.

[0032] Please refer to Figures 1 to 3 This embodiment provides a large cannon barrel aerator, which is used to increase the amount of dissolved oxygen in water and promote water circulation in the water body, thereby improving water quality.

[0033] The large cannon barrel aerator includes: an air pump 14, an aeration pipe 12, a transfer pipe 9, a connecting pipe, an air pump air inlet transfer terminal 4, and an air pump air outlet transfer terminal 5. The connecting pipe includes an air inlet pipe 3 and an air outlet pipe 6. One end of the air inlet pipe 3 is an air inlet, and the other end is connected to the air pump air inlet transfer terminal 4. The other end of the air pump air inlet transfer terminal 4 is connected to the air pump 14. One end of the air pump air outlet connection terminal 5 is connected to the air pump 14 and the other end is connected to the air outlet pipe 6. The transfer pipe 9 has a port connected to the air outlet pipe 6 and a plurality of connection terminals. There are multiple aeration pipes 12, and they are respectively connected to the corresponding connection terminals. The air pump 14 drives the air to pass through the air inlet pipe 3, the air pump air inlet transfer terminal 4, the air pump 14, the air pump air outlet transfer terminal 5, the air outlet pipe 6, and the transfer pipe 9 in sequence, and then enters the aeration pipe 12 and enters the water body through the aeration pipe 12.

[0034] For further information, please refer to Figure 1 The large cannon barrel aerator also includes a rain cover 1 and an air filter 2. The rain cover 1 is fixed above the air inlet to prevent rainwater from entering the air inlet pipe 3, and the air filter 2 is fixed in the air inlet pipe 3. The air enters the air inlet pipe 3 from the air inlet and is filtered by the air filter 2, and then enters the air pump 14 through the air pump air inlet adapter terminal 4, and enters the air outlet pipe 6 through the air pump air outlet adapter terminal 5 after being pressurized by the air pump 14, and then enters the adapter tube 9 from the air outlet pipe 6, and finally enters the water flow in the large water pipe 13 through the micropores of the aeration pipe 12.

[0035] The wall of the aeration tube 12 has micropores for air to pass through and to prevent water from entering the aeration tube 12. The number of micropores is not less than 17,000 / m. The numerous micropores burst tiny bubbles, increasing the surface area of ​​contact between air and water, thereby increasing the amount of dissolved oxygen. There are multiple aeration tubes 12, and the multiple aeration tubes 12 extend forward and backward and aerate evenly along the tube path. Each aeration tube 12 is connected to the transfer tube 9 respectively, and the end of the aeration tube 12 away from the transfer tube 9 is isolated to ensure that there is sufficient air pressure in the aeration tube 12.

[0036] Please refer to Figure 1 The large cannon barrel aerator also includes a plug flow pump and a large water pipe 13. The plug flow pump includes a cylindrical housing 10 and a spiral impeller 210 is arranged in the cylindrical housing 10. The large water pipe 13 is connected to the rear end of the cylindrical housing 10 and extends backward. The transfer tube 9 passes through the cylindrical housing 10 and is fixed behind the spiral impeller 210. The aeration pipe 12 is fixed to the connection terminal of the transfer tube 9 and is located in the large water pipe 13 and extends backward.

[0037] The working process of the large cannon barrel aerator provided in this embodiment is as follows: the spiral impeller 210 of the plug flow pump rotates, sucking water from the front of the cylindrical shell 10, and forming a water flow moving backward. When passing through the area enclosed by the large water pipe 13, the aeration pipe 12 located in the large water pipe 13 inputs air into the water flow, and the water flow mixed with air continues to move backward until it leaves the large water pipe 13.

[0038] The large barrel aerator provided in this embodiment improves the oxygenation efficiency and the amount of dissolved oxygen per unit energy consumption by combining the plug flow pump, the large water pipe 13 and the aeration pipe 12, thereby achieving the effect of oxygenation and energy saving. Specifically:

[0039] The aeration tube 12 is fixed in the large water pipe 13 to form a tube in a tube. The tiny bubbles released from the micropores of the aeration tube 12 merge with the flowing water. The water flows into the large water pipe 13 in an unsaturated state, leaves the large water pipe 13 after being fully saturated, and diffuses to the surroundings with the outlet of the large water pipe 13 as the center, thereby increasing the dissolved oxygen content of the water body and expanding the oxygenation range.

[0040] Under the setting of the large water pipe 13, the water flows into from the front of the plug flow pump and then leaves from the water outlet of the large water pipe 13, and merges into the water body outside the large water pipe 13. After a long time, it enters from the front of the plug flow pump again, forming a large-scale circulation of water flow, which is conducive to the isolation of oxygen-rich water and oxygen-deficient water that has just completed oxygenation, and greatly improves the dissolved oxygen content per unit energy consumption.

[0041] The use of the large water pipe 13 also prolongs the aeration time of the water flow. Assuming that the large water pipe 13 is 5 meters, the water flows in the large water pipe 13 at a flow rate of less than 0.5 meters per second, and has an aeration time of more than 10 seconds. The aeration is sufficient and the oxygen utilization rate is high, which is a technical advantage completely different from the existing aerator. In order to ensure that the water flow has enough oxygenation time, the water flow speed in the large water pipe 13 should be controlled below 1 meter per second, specifically from the water outlet speed of the plug flow pump, the diameter of the spiral impeller, and the diameter of the large water pipe. In addition, the largeness of the large water pipe 13 is a relative concept. The total flow rate generated in 6 hours should be greater than the total amount of water in the water body served by the water pipe at a speed of 1 meter per second.

[0042] In order to further improve the oxygenation efficiency and energy-saving effect, this embodiment also provides a method for energy-saving oxygenation of a large barrel aerator, comprising the following steps:

[0043] The plug flow pump has a cylindrical housing 10 and a spiral impeller 210, and the spiral impeller 210 rotates at less than 200 revolutions per minute to push water backward to form a water flow;

[0044] The large water pipe 13 is connected to the rear end of the cylindrical housing 10 and extends along the direction of the water flow. The large water pipe 13 guides the water flow to move backward and spreads it to the surroundings at the water outlet of the large water pipe 13;

[0045] An aeration pipe 12 is placed in the large water pipe 13. The aeration pipe 12 extends along the direction of the water flow. The aeration pipe 12 inputs air into the water flow in the large water pipe 13.

[0046] The water flow velocity in the large water pipe 13 is controlled to be less than 1 m / s, and the volume ratio of the air flow of the aeration pipe 12 to the water flow of the large water pipe 13 is less than 1:5.

[0047] The energy-saving oxygenation method of the cannon barrel aerator provided in this embodiment adopts the above-mentioned cannon barrel aerator, and controls the rotation speed of the spiral impeller 210, the flow rate of the aeration pipe 12, and the water flow speed in the large water pipe 13, so as to achieve efficient oxygenation while taking energy saving into consideration.

[0048] The energy-saving effect is mainly reflected in:

[0049] 1. The spiral impeller 210 pushes the flow axially at a speed lower than 200 rpm. Under the same power, the water flow rate is increased by reducing the water flow velocity, or in other words, the power required to push the same water flow rate is smaller, thereby achieving energy saving.

[0050] 2. As mentioned above, the large water pipe 13, the plug flow pump, the aeration pipe 12 and other structural arrangements increase the amount of dissolved oxygen. The increase in the amount dissolved per unit time, that is, the increase in dissolution efficiency, also represents an increase in effective energy conversion, thereby achieving an energy-saving effect.

[0051] 3. The water flow velocity in the large water pipe 13 is controlled to be less than 1 m / s, and the volume ratio of the air flow rate of the aeration pipe 12 to the water flow rate in the large water pipe 13 is less than 1:5. At 20°C and standard atmospheric pressure, 1 liter of water can only dissolve 7-9 mg of oxygen, while 1 liter of air can contain up to 300 mg of oxygen. In the actual oxygenation process, since the water body already contains a certain amount of oxygen, it only needs to add 4-5 mg of oxygen per liter of water to make it saturated. Therefore, the aeration volume of the aeration pipe 12 and the water flow volume ratio in the large water pipe 13 are controlled below 1:5, which is conducive to increasing the dissolved amount of oxygen in the unit energy consumption. The reduction of aeration volume will reduce the power required by the air pump.

[0052] Please refer to Figure 2 The large cannon barrel aerator provided also includes a motor 15 and a speed reduction and speed change mechanism 16. The motor 15 is a double-axle extension motor and drives the air pump 14 and the speed reduction and speed change mechanism 16 at the same time. The output shaft 17 of the speed reduction and speed change mechanism 16 is fixedly connected to the spiral impeller 210. In the illustrated embodiment, the output shaft 17 of the speed reduction and speed change mechanism 16 is fixedly connected to the impeller shaft 213 of the spiral impeller 210 through the coupling 18.

[0053] In this embodiment, the rated speed of the motor 15 is not less than 2800 rpm, and the speed of the output shaft 17 of the speed reduction mechanism 16 is 60 to 200 rpm. The lower the speed, the larger the outer diameter of the blade 212 of the spiral impeller 210.

[0054] The motor 15 can be an AC motor or a brushless DC motor. The motor 15 drives the plug flow pump and the air pump 14 at the same time, saving the number of equipment (compared to two motors driving the air pump and the plug flow pump respectively), reducing the use of copper and iron core materials, and also avoiding unnecessary copper loss and iron loss, greatly improving the power efficiency of the entire aerator. On the other hand, the space occupied by the equipment is reduced, the length of the connecting pipe is reduced, thereby reducing the air pressure loss and enhancing the aeration capacity of the air pump 14.

[0055] The speed reduction and speed change mechanism 16 converts the output energy of the high-speed rotation of the motor 15 into a low-speed and high-torque rotation acting on the impeller shaft 213. Under the same power, reducing the speed is conducive to increasing the thrust (P=F*V), and increasing the thrust can simultaneously drive a larger volume of water flow, so that a large volume of water flows slowly through the area where the aeration pipe 12 is located. A lower speed is conducive to the full dissolution of water and air, and a large flow of water represents an increase in solvent, thereby increasing the amount of oxygen dissolved. In addition, the low-speed rotation of the spiral impeller 210 is conducive to reducing water turbulence, thereby reducing energy loss.

[0056] Please refer to Figure 1-3 The plug flow pump includes a water filter grid 7, a spiral impeller 210, an impeller shaft 213, a front bearing 216, a rear bearing, a front bracket 214, a rear bracket 215, and a cylindrical shell 10. The front bracket 214 and the rear bracket 215 are both hollow structures. The spiral impeller 210 is sleeved on the impeller shaft 213 and fixedly connected to the impeller shaft 213. The front bearing 216 is fixed on the front bracket 214, and the rear bearing is fixed on the rear bracket 215. The rear end of the impeller shaft 213 is slidably connected to the rear bearing, and its front end passes through the front bearing 216 and is connected to the speed reduction mechanism 16.

[0057] The cylindrical shell 10 is fixedly connected to the front bracket 214 and the rear bracket 215 to enclose and form a flow-pushing chamber for accommodating the spiral impeller 210. Behind the flow-pushing chamber is a water outlet chamber. The rear end of the water filter grid 7 is connected to the cylindrical shell 10, and a water inlet chamber is formed inside the water filter grid 7.

[0058] Driven by the motor 15, the impeller shaft 213 rotates so that water passes through the filter water grid 7 into the water inlet chamber, and then passes through the front bracket 214 into the flow chamber. Under the thrust of the rotating spiral impeller 210, the water moves backward to form a water flow, passes through the rear bracket 215 into the water outlet chamber, and then enters the large water pipe 13.

[0059] The beneficial effects of each structure also include:

[0060] The setting of the water filter grid 7 isolates large pieces of garbage in the water body from entering the plug flow pump, thereby increasing the service life of the spiral impeller 210 and improving the overall structural strength of the aerator.

[0061] The front bracket 214, the rear bracket 215 and the impeller shaft 213 provide a structural frame to ensure the structural strength of the plug flow pump.

[0062] The front bearing 216 and the rear bearing adopt ceramic bearings, which do not require lubrication and waterproofing, thereby improving the applicability of the structure.

[0063] Please refer to Figure 3 In this embodiment, the driving efficiency of the spiral impeller 210 is improved by designing the blades 212 of the spiral impeller 210, thereby achieving energy saving effect:

[0064] The spiral impeller 210 includes a hub 211 and a single blade 212 fixed to the hub 211. Compared with the multi-blade design, the design of the single blade 212 can effectively reduce the generation of water turbulence at the same speed, thereby improving the conversion rate of the rotational energy of the spiral impeller 210 into the kinetic energy of the water moving backward, thereby improving the efficiency of pushing water. In this embodiment, each section of the blade 212 is set to be of equal thickness. The equal thickness setting is conducive to saving equipment manufacturing costs.

[0065] Preferably, the pitch ratio of the spiral impeller 210 is in the interval [0.5, 1], and the pitch ratio is the ratio of the axial length of the leading edge of the blade 212 along the spiral line of the blade 212 to the diameter of the spiral impeller 210. The leading edge of the blade 212 is the line from the point where the front end of the blade 212 intersects with the hub 211 to the point where the blade 212 is farthest from the hub 211. It has been proved by many experiments that under this pitch ratio, the spiral impeller 210 has good water pushing efficiency.

[0066] In another embodiment, the pitch ratio of the spiral impeller 210 is in the range of [0.5, 0.75]. Under this pitch ratio, the water pushing efficiency of the spiral impeller 210 is further improved.

[0067] In this embodiment, the axial projection area of ​​the blade 212 is equal to the disk area, and the disk area is the axial projection area of ​​the area covered by the rotation of the blade 212. That is, the blade 212 is formed by the guide edge rotating one circle along the spiral line of the blade 212. This design guides the water flow and reduces the generation of turbulence.

[0068] Preferably, the radial distance between the blade 212 and the housing is less than or equal to 2 mm. The small gap reduces the amount of water in the gap, thereby improving the efficiency of the blade 212 in pushing water.

[0069] In this embodiment, the motor 15 is 300W, the diameter of the spiral impeller 210 is 30CM (when the motor 15 is 500W, the diameter of the spiral impeller 210 is increased by 40%), the spiral impeller 210 is a spiral single impeller, the axial length of a single spiral circle exceeds 20CM, and the total number of spiral circles of the blades 212 of the spiral impeller 210 is not less than one circle.

[0070] In this embodiment, the motor 15, the speed reducing gearbox 16 and the air pump 14 are designed to be waterproof as a whole:

[0071] The oxygenation equipment also includes a watertight compartment 8, in which the motor 15 and the air pump 14 are fixed, and the speed reduction and speed change mechanism 16 is fixed in the watertight compartment 8, and its output shaft 17 passes through the watertight compartment 8 and is connected to the impeller shaft 213. That is, the electromechanical structure of the aerator is enclosed as a whole by setting up the watertight compartment 8. A through hole for the output shaft 17 to pass through is provided in the watertight compartment 8 and a waterproof design is made. The sealing method of the output shaft 17 can adopt liquid magnetic sealing, magnetic contactless drive isolation cover sealing, etc. An air pump air inlet and an air pump air outlet are provided in the watertight compartment 8, which are respectively connected to the air pump air inlet adapter terminal 4 and the air pump air outlet adapter terminal 5, and a waterproof design is made. The waterproof method can be welding or setting a watertight ring, etc.

[0072] The watertight compartment 8 and the plug flow pump are both detachably connected to the water filter grid 7. The oxygenation equipment can be disassembled into four major parts: the watertight compartment 8 where the motor 15, the speed reduction gearbox and the air pump 14 are located; the plug flow pump; the water filter grid 7; the large water pipe 13, the aeration pipe 12, the air intake pipe 3 and other parts. This design facilitates the disassembly and transportation of the equipment.

[0073] In this embodiment, the large water pipe 13 is a water pipe made of soft and foldable material, so as to facilitate installation and transportation. The large water pipe 13 and the plug flow pump are connected through a connecting assembly 11.

[0074] The connection assembly 11 includes a clamp, a screw and a nut. The clamp is annular and has a left through hole and a right through hole at both ends for the screw to pass through. The outer surface of the plug flow pump is provided with a limit groove that matches the clamp. The water pipe is inserted into the plug flow pump forward so that the front pipe edge of the water pipe is located at the limit groove or exceeds the limit groove. Then the clamp is sleeved on the water pipe and located above the limit groove. The screw passes through the left through hole and the right through hole and is connected to the nut to fix the large water pipe 13 on the plug flow pump.

[0075] Furthermore, the screw is a butterfly screw, or the nut is a butterfly nut, thereby achieving tool-free disassembly and assembly.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A large cannon barrel aerator, comprising: An air pump, an aeration pipe, and a connecting pipe, wherein the air pump drives air to enter the aeration pipe through the connecting pipe and then enter the water body through the aeration pipe, wherein the large barrel aerator further comprises: A plug flow pump, the plug flow pump comprising a cylindrical housing and a spiral impeller arranged in the cylindrical housing; A transfer pipe, used to connect the connecting pipe and the aeration pipe, the transfer pipe passes through the cylindrical housing and is fixed behind the spiral impeller; A large water pipe connected to the rear end of the cylindrical shell and extending backward; Wherein, the aeration pipe is fixed to the connection terminal of the transfer pipe and is located inside the large water pipe and extends backward; The helical impeller comprises a hub and a single blade fixed on the hub, the pitch ratio of the helical impeller is in the interval of [0.5, 1], the pitch ratio is the ratio of the axial length of the leading edge of the blade along the helical line of the blade for one rotation to the diameter of the helical impeller, the leading edge of the blade is the line between the point where the front end of the blade intersects with the hub and the point where the blade is farthest from the hub; or The helical impeller comprises a hub and a single blade fixed on the hub, the pitch ratio of the helical impeller is in the interval of [0.5, 0.75], the pitch ratio is the ratio of the axial length of the leading edge of the blade rotating along the spiral line of the helical impeller for one circle to the diameter of the helical impeller, the leading edge of the blade is the line between the point where the front end of the blade intersects with the hub and the point where the blade is farthest from the hub; The axial projection area of ​​the blade is equal to the disk area, and the disk area is the axial projection area of ​​the area covered by the rotation of the blade; The radial distance between the blade and the housing is less than or equal to 2 mm.

2. The large barrel aerator according to claim 1, characterized in that: The large cannon barrel aerator also includes an electric motor and a speed reduction and speed change mechanism. The electric motor is a double-axle extension electric motor and drives the air pump and the speed reduction and speed change mechanism at the same time. The output shaft of the speed reduction and speed change mechanism is fixedly connected to the spiral impeller.

3. The large barrel aerator as claimed in claim 2, characterized in that: The large cannon barrel aerator also includes a watertight compartment, the electric motor and the air pump are fixed in the watertight compartment, the speed reduction and speed change mechanism is fixed in the watertight compartment and its output shaft passes through the watertight compartment and is connected to the spiral impeller shaft.

4. The large barrel aerator as claimed in claim 3, characterized in that: The plug flow pump also includes a water filtering grid frame, the front end of which is connected to the watertight compartment and the rear end of which is connected to the cylindrical shell, and the water enters the cylindrical shell through the water filtering grid frame.

5. A method for energy-saving oxygenation using a large barrel aerator according to any one of claims 1 to 4, characterized in that: The following steps are involved: The plug flow pump has a cylindrical housing and a spiral impeller, and the spiral impeller rotates at less than 200 rpm to push water backward to form a water flow; A large water pipe is connected to the rear end of the cylindrical shell and extends along the direction of the water flow, and the large water pipe guides the water flow to move backward and spreads it to the surroundings at the water outlet of the large water pipe; An aeration pipe is placed in the large water pipe, the aeration pipe extends along the direction of water flow, and the aeration pipe inputs air into the water flow in the large water pipe; The water flow velocity in the large water pipe is controlled to be less than 1 m / s, and the volume ratio of the air flow of the aeration pipe to the water flow of the large water pipe is less than 1:5.

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