Reducer type paddlewheel aerator VS BLDC motor inverter aerator

Currently, most of the aerators are AC induction motor (asynchronous motor) aerators with gearbox (reduction gear).

In China, the proportion of BLDC motor aerators used in aquaculture is increasing year by year, while the proportion of the market with gearbox aerator is decreasing year by year, this article will analyze the difference between the two kinds of aerators. This article will analyze the differences between the two types of aerators for your reference.

Different structure:

induction motor AC induction motor structure:

asynchronous motor asynchronous motor is divided into squirrel cage type three-phase asynchronous motor and wire wound three-phase asynchronous motor. Stator by the base, stator core, stator winding; rotor by the rotor core, rotor winding (or squirrel cage), as well as the corresponding shaft and bearings are composed. The base of the three-phase asynchronous motor has a heat dissipation rib, which increases the heat dissipation function of the asynchronous motor. The shaft of the three-phase asynchronous motor is equipped with a fan to help dissipate the heat.

Permanent magnet synchronous motor structure:

The vast majority of high-speed permanent magnet synchronous motors use a built-in rotor structure, the permanent magnets are located in the core between the squirrel cage guide bars and the rotor shaft; the squirrel cage guide bar structure provides the same principle as an asynchronous motor to start the motor, there is no can't be started, unless by other starting methods.

A permanent magnet synchronous motor consists of a stator, rotor, and end cover components. The stator is basically the same as an ordinary induction motor, with a laminated structure to minimize iron consumption during motor operation. The rotor can be made solid or laminated.

Different working principle

AC induction motor working principle:

An asynchronous motor is the stator inputs alternating current (utility 50Hz/60Hz), generating a rotating magnetic field, while the rotor is induced to produce a magnetic field so that the two magnetic fields so that rotor follow the rotating magnetic field of the stator and rotate. The rotor is slower than the stator rotating magnetic field, there is a rotational difference, not a synchronized so-called asynchronous motor. The speed difference of the asynchronous motor follows the change in load size.

Principle of operation of BLDC motor:

Synchronous motor rotor in the iron core surface affixed with pairs of magnets or iron core inserted into pairs of magnets to form an unchanging magnetic field, so that the rotor will follow the stator rotating magnetic field - up to the turn and synchronization, began to be called synchronous motor. Synchronous motor regardless of the load size, as long as not out of step, the speed will not change; the speed of the motor is determined by the frequency of the input current and the number of magnetic poles of the motor.

Brushless DC Inverter Paddle Wheel Aerator

is an alternating current (AC) that is converted to direct current (DC) and then converted to the frequency of the required speed.

Why does an asynchronous motor aerator need a gearbox reducer?

The speed of a three-phase asynchronous motor is fixed, usually around 1500 rpm for a 4-pole motor (or 2800 rpm for a 2-pole motor). The impeller speed of an asynchronous motor oxygenator is 110 rpm. If you need to change the speed, you need to use a reducer. gearbox reducer is a mechanical transmission device that converts the high-speed rotational power of the input shaft to the low-speed rotational power of the output shaft to decelerate and increase the force. A reducer usually consists of gears, bearings, oil seals, and other components. During the deceleration of the motor through the gearbox, electrical energy is lost by about (10-20%) (depending on the newness and quality of the aerator), and the efficiency of an asynchronous motor is about 80-70%, depending on the quality.

Why does a BLDC motor aerator not need a gearbox?

The magnetic field created by the fixed permanent magnets in a DC motor (brush motor) does not move but is rotated by the magnetic field created inside the coil (rotor) by the brush control coil in the sequence of energization and de-energization. The number of rotations is changed by changing the voltage. BLDC motors are based on DC motors, and instead of mechanical brushes, inverters (controllers) are used to energize the stator coils at a programmed frequency to form a rotating magnetic field that rotates the rotor of the magnets. By controlling the direction and size of the current to the coil to control the rotation of the rotor.

BLDC motors use permanent magnets as the rotor. Since there is no need to energize the rotor, brushes, and commutator are not required. Electricity to the coil is controlled externally.

Rotor Differences:

The main structural difference between a permanent magnet synchronous motor and an induction asynchronous motor is the rotor. The asynchronous motor rotor has no permanent magnets, only the excitation winding (or squirrel cage).

A synchronous motor rotor has no excitation winding but only permanent magnets.

Why does a Brushless DC Inverter aerator save power?

Since the magnetic field of the BLDC aerator motor is generated by NdFeB (a type of permanent magnet), it is possible to avoid generating the magnetic field through the excitation current, which leads to copper consumption (resistance heating), and the copper consumption is low and the efficiency is high.

Because BLDC motor rotor operation does not need excitation current, reduces the temperature rise of the motor, the same load, permanent magnet synchronous motor temperature rise is low, low energy consumption, to achieve the purpose of power saving and energy saving.

Permanent magnet synchronous motor power density and torque density are high, compared with the asynchronous motor under the same power and torque, lightweight, and small size.

Asynchronous motor oxygenator advantages and disadvantages:

Asynchronous motor advantages:

no permanent magnet (NdFeB), low cost, low price.
Easy maintenance

Disadvantages:

maintenance trouble, every 6 months or 4000 hours to replace the lubricating oil.
Periodic painting to prevent corrosion.
Large size
Heavy machine.
Not energy-saving, high power consumption.
Noise, the longer the oxygenator is used, the greater the noise.
Lack of phase burning motor.

Complicated installation, if the motor and gearbox are installed incorrectly, it will greatly shorten the service life of the machine.

Machine oil leakage will cause pond pollution. Fish and shrimp death.

As the birth rate decreases and labor costs increase, the cost of maintaining the machine will continue to rise

Inverter aerator advantages and disadvantages

Pros:

Gearbox type aerator, BLDC paddlewheel motor inverter aerator has a higher efficiency of 90-93% (high-speed motor), and the permanent magnet synchronous motor can run at low speed and high torque (compared to the high-speed motor, the efficiency will be reduced), it can directly drive the load without a gearbox. Power consumption is 70% of the asynchronous motor, about 30% power savings.

The speed of the permanent magnet synchronous motor is adjusted by the controller according to the program, and the speed starts slowly after the aerator starts, which doesn't hurt the body of the fish and shrimp.

Extremely low noise

No oil, (no need to gearbox deceleration torque increase)

The machine is light and easy to carry.

Wide range of voltage operation, for example, 380V AC, the oxygenator can run at 260V-450V.

No burning of the motor during phase failure.

Easy to install

Disadvantage:

BLDC motor permanent magnet is made of rare earth material, expensive cost.

Difficult to repair

Types of automatic feeders used in Aquaculture

1. According to the feeding form, feeders are mainly divided into centrifugal feeders, air-driven feeding machines

, and drop-type feeders.

1.1Centrifugal fish feeder

Centrifugal auto feeder: It consists of a feed box, a controller, a feeding mechanism for throwing motion, a throwing motor, a throwing plate, etc. The feeding form is a mechanical centrifugal throwing feeder. This is the most common type of feeder in aquaculture, suitable for pellet feed, and is often used in outdoor small and medium-sized ponds.

Main features:

The hopper is composed of a box with a cover, which has a moisture-proof function;
The eccentric wheel is driven by a motor to vibrate and feed, avoiding blockage of the feeding pipe;
The feeding form is mechanical centrifugal throwing, and the throwing area is large;
It is suitable for pellet feed, not for powder feed;
It occupies a small area, has a simple structure, is easy to operate, and is easy to maintain.

1.2Air conveying feeder

Air-conveying feeder: It consists of a feed box, a feeding mechanism, a feeding mechanism (air compressor or fan, a conveying pipe, a conveying distribution device, etc.) and a controller.

There are two feeding methods: one is a feeding method that relies solely on windpipe injection, which is often used in the circulating aquaculture raceway breeding mode. The other is to use a motor to drive the scattering disc to rotate and suck the feed into the scattering disc to achieve 360° scattering of feed. It is often used in large water surface breeding environments such as cages and reservoirs.

Main features:

The feed box is large and the feed storage capacity is large;
The feed transmission distance is long and the feeding capacity is strong;
Suitable for pellet feed;
The scattering area is large and can be used for large water surface breeding.

Drop type feeder

1.3 Drop-type feeder: It consists of a feed box, a feeding mechanism, and a controller, and the feeding form is a free-falling feeder.

There are usually two types of feeding mechanisms: one is that the motor drives the feeding plate to rotate, and the feed falls centrifugally. The other is that the motor drives the spiral auger to rotate, and the feed in the silo is transferred to the feeding port, which is set at the end of the spiral auger to discharge the feed. Drop-type feeders are often used for factory/experimental breeding of fry or small feeding amount

Main features:

Small size and lightweight;
Suitable for small particle feed such as powder;
Only used for small breeding ponds such as fry;
Simple structure and cheap price.

Fish Farm Supply Co Inc. of Canada has developed a self-demand feeder based on the drop-down feeder (as shown in Figure 4). This type of feeder does not require power supply. When the farmed fish enter the bait delivery area and trigger the switch of the underwater device of the feeder, the feed outlet will open and drop the feed. It has the characteristics of simple structure, simple maintenance, and low cost. However, this type of feeder has requirements on the learning ability and training of fish, and individuals with higher social status in the fish school will occupy the triggering and bait delivery area of the feeder and prevent other individuals from approaching this area, which may easily cause obvious differences in the size of fish individuals; the trigger sensor device is prone to frequent "unintentional" triggering by individuals in the fish school, resulting in feed waste.

2. According to the application environment, feeding machines are divided into pond feeding machines, cage feeding machines and RASfeeding machines.

2.1 Pond feeders

Pond fish farming feeders: Since the feed used in pond farming is mainly pellet feed, the use of feeders is usually divided into two situations according to different farming environments. Centrifugal feeders are used in small and medium-sized ponds, and air-assisted feeders are used in large water surfaces and reservoirs. To improve the feeding efficiency in this scenario, unmanned boats and drones are gradually being used.

2.2Cage fish farming feeders

Cage feeders: Cage feeders are divided into surface cage feeders and deep-water cage feeders.

2.2.1 Surface cage feeders

Surface cage feeders use air-assisted feeders to sprinkle feed in the middle area of the cage through a distribution device and a feeding device. Surface cage feeders are often used in cages in waters with small winds and waves.

2.2.2 Deep-water cage feeders

Deep-water cage feeders need to deliver feed directly to the center of the cage a few meters below the water surface.

The feeding speed is controlled by adjusting the water pump, and then the fish are fed using the distribution device and the feeding device. The feeding effect is better when the light is used in conjunction with the cage feeder. Deep-water cage feeders are often used for breeding in oceans, reservoirs, and other waters. Because sea bass, grouper, salmon, and other marine fish are often eaten abroad, and marine aquaculture is mainly caged, the cage feeder is a common feeder abroad.

Main features:

1. Modified based on the air-conveying feeder;

2. Large feed box, large feed storage capacity;

3. Long feed transmission distance, strong feeding capacity;

4. Feed is thrown on the water surface in the middle area of the net cage.

2.3 RAS fish farming feeder

RAS feeder: Usually a walking system consisting of tracks, walking pulleys, and positioning sensors is combined with a drop-type/centrifugal feeder to complete the feeding work. Generally, the feeder is required to feed accurately and can be remotely monitored through the Internet to achieve automatic management.

Main features:

It has the functions of feed storage, metering, and spreading;
Accurate feeding;
The high degree of automation and integration.
Intelligent precision feeding system
The traditional feeding machine can only set the feeding amount each time according to the experience of fishermen, and cannot sense the changes in a series of environmental factors such as water quality and weather to decide whether to feed or increase or decrease the feeding amount. Therefore, it cannot be well adjusted in real time according to the growth of fish. Most of the current feeding machines simply replace the process of manually throwing feed.

At present, most of the research on precision feeding at home and abroad is based on the theoretical feeding rhythm of the aquaculture objects, that is, feeding is carried out at a fixed time with a specific feeding strategy, and feeding is selectively stopped depending on the satiety of the fish, which belongs to passive feeding. The difficulty of this type of research/application lies in how to accurately quantify the degree of feeding desire of the aquaculture objects during the feeding process.

With the help of acoustic technology and computer vision, the feeding needs of fish during feeding are often realized through quantitative analysis of the feeding behavior, feeding audio and residual bait amount of farmed animals, and the feeding time and feeding amount are automatically adjusted according to the real-time feeding needs.

AQ1 Systems Pty Ltd of Australia has designed a feeding system that uses feeding audio. Using hydrophone sensors, the feeding activity of fish is determined by measuring the "feeding" sound. The system has an adaptive feeding algorithm to control the feeding rate and is built to high-quality marine standards. This easy-to-maintain system provides farmers with flexible and cost-effective feeding control and environmental monitoring. The feeding system can be combined with different types of feeders to adapt to different farming environments.

There are not many feeding devices based on computer vision on the market. The working principle of feeding devices mainly consists of two aspects:

Use an underwater camera to shoot the residual bait at the bottom of the cage. When the amount of residual bait is lower than the preset threshold, the feeder will start feeding.

Monitor the position and density of fish, quantify the hunger or feeding desire of the fish school through relevant means, and then feed the signal back to the control system to control the working status of the feeder.

In addition to the above methods, changes in water quality parameters (such as water temperature and dissolved oxygen) during feeding can also provide a reference for assessing fish feeding needs.

The robot feeding system designed by Arvo-tec of Finland is characterized by a small feeding volume but high precision. This system consists of 1 to 4 small funnel-shaped feeding units - feeding robots, which move between the various breeding ponds along the track installed above the breeding pond to feed.

The system can monitor water temperature and dissolved oxygen concentration, and then feed the data back to the control system and automatically make certain corrections to the feeding program to meet any slight changes in feed demand. And when the feeding robot reaches the feeding point on the track, the large silo can automatically refill the feed to the small funnel-shaped silo on the robot.

5. According to the feeding position of the feeder, it is divided into fixed and mobile feeders.

5.1 Fixed feeders

Main features:

The fixed feeder has a simple structure and is easy to maintain.
Suitable for ponds that are not very large and suitable for fish farming.
Convenient loading and unloading of feed.

5.2 Moving automatic feeder

Main features:

1. The operating procedures and design structure are slightly complex and have higher requirements for users.

2. The machine moves and feeds, feeding more evenly, ensuring that most fish and shrimp can eat the feed.

3. Save feed, improve feed conversion rate, and reduce feed ratio by up to 20%. Shrimp or fish farms can avoid feed waste.

cost, significantly reducing breeding costs.

4. Since the machine is working on the move, there are requirements for the wire distribution of the aerator in the shrimp pond, and there must be no other wires blocking the moving path.

Different types of aerators in aquaculture

A pond aerator is an effective device to increase the amount of dissolved oxygen in aquaculture ponds. The aerator must operate deep in the pond to improve the soil quality at the bottom of the pond and avoid the production of toxic gases in the subsoil to effectively prevent the problems of tilapia and shrimp. Possibility of death from disease. The aerator is a device that quickly transfers "oxygen" from the air to the breeding water body. It can solve the problem of floating heads of breeding animals due to lack of oxygen in pond breeding, eliminate harmful gases, promote convective exchange in the water body, and improve water quality conditions. , reduce the feed coefficient FCR Feed conversion ratio, improve aquaculture productivity, thereby increasing the stocking density, increasing the feeding intensity of fish and shrimp, promoting growth, greatly increasing the unit output, and fully achieving the purpose of increasing the income of fish farming and shrimp farming.

There are many types of aerators, including impeller aerators, paddlewheel aerators, floating fountains, Oxygen Generator, and jet aerators, etc.

It is subdivided according to the mode of supplying energy. diesel engine water pump. #diesel engine paddle wheel aerator,aireador solar para piscicultura #aireadores solares para acuicultura and electric aerators.

Fountain aerator

#scott aerator #pond pump #fountain pump principle: Pump up the water with poor water quality in the lower part of the pool and spray it upward, around, or forward at high speed.

Advantages:

1.1. It can extend and expand the time and area of aeration and oxygenation in the air;

1.2 It has a good oxygenation function, which can quickly increase the dissolved oxygen content of surface water in a short period. It also has an artistic viewing effect and is suitable for use in fish ponds gardens or tourist areas.

Disadvantages:

Due to its small effective oxygenation area and poor energy consumption conversion, it is currently only used in parks, sightseeing fish ponds, small ponds, etc. It is not only beautiful, but also practical.

Air jet aerator

Principle: The centrifugal pump rotates to suck in oxygen-deficient water from the bottom of the pond and pressurizes it, accelerating the input to the jet. When the water is ejected from the nozzle, a high-speed water column jet containing a large number of bubbles is formed. This water column is injected into the pond water body and creates a Convection to achieve the effect of oxygenating the pond

Advantages:

2.1. Simple structure, can form water flow and stir water;

2.2. The jet aerator can slowly oxygenate the water body without damaging the fish's body. It is suitable for use in aquaculture hatcheries Prawn hatcheries and nursery ponds.

Disadvantages:

The oxygenation effect is not ideal. In actual production, it is often made into a jet-type oxygenation feeding boat to achieve the dual effect of adding oxygen while feeding. The oxygenation area is small, and it is easy to wash the silt from the bottom of the pool to the water surface.

3,.paddlewheel aerator #kincir air tambak #aireadores #aireadores de paletas

Principle: Two rectangular parallelepiped pontoons are used as buoyancy devices. The motor is mounted on the pontoons to drive the vertical impeller in the middle to generate water waves to achieve the effect of increasing oxygen.

Advantages:

3.1. The whole machine is light in weight, simple in structure, low in cost, and has a good oxygenation effect in shallow ponds;

3.2. It has a strong push flow ability and certain mixing ability in the middle and upper layers, which can obtain a better contact area between oxygen and water, and has high oxygenation efficiency;

3.3. Arrange more than 2 paddlewheel aerators in the pond to form directional water flow throughout the pond.

Disadvantages:

3.1. The lifting force for bottom water is not large enough, and the oxygenation effect in deep water areas is not ideal;

3.2. It is not suitable for first aid when aquaculture animals float.

impeller aerator impeller aerator

Principle: The impeller sucks up the oxygen-deficient water at the bottom of the pond, and then pushes it out in all directions to make the water flow. The water under the impeller is strongly stirred by the blades and tubes, stirring up waves on the surface of the water, forming a water curtain that can be wrapped into the air. As the impeller is rotating, negative pressure is formed at the back of the stirring pipe so that the air can be sucked into the water through the stirring pipe, and it is immediately stirred into micro-bubbles to enter the pressure area of the impeller, so it is also helpful to improve the dissolution speed of oxygen in the air and improve the efficiency of oxygenation.

Advantages:

1. Lifting and stirring. Impeller oxygenator can lift the bottom water, so that it alternates with the surface water, so as to play to the bottom water oxygenation effect, its pond oxygenation depth of more than 2 meters;

4.2 the mechanical structure is relatively simple, in the use of the process of mechanical failure rarely occurs, maintenance is more convenient, reducing maintenance costs;

4.3 in the process of use can form the upper and middle water flow so that the upper and middle water body dissolved oxygen uniformly, suitable for pond breeding and pond first aid equipment;

4.4 aeration in addition to harmful gases. Impeller aerator has a strong aeration function, harmful gases in the pond water such as ammonia, hydrogen sulfide, methane, carbon monoxide, etc. can be effectively aeration.

Disadvantages:

4.1 it must be in smooth conditions of electricity can be used, in remote mountainous areas of lack electricity, and set up wires, the cost is higher;

4.2 the oxygenator generally must be fixed at a point in the pond, change the location of the more troublesome, and the oxygenation area is limited to a certain range, for larger ponds on the bottom of the water body the oxygenation effect is poor;

4.3the aerator's float is exposed to the air all year round, after sunlight exposure, it easily corrodes and damaged, and needs to be replaced frequently;

4.4 belongs to a single point of oxygenation, and mechanical operation noise, easily affects the growth of aquatic animals and injury to aquatic animals;

4.5 the impeller oxygenator is easily to the bottom of the pond mud pumped up, not suitable for use in shallow ponds.

microporous aeration oxygenator and blower

Principle: the use of a roots blower air blower air suspension blower or oxygen concentrator, most people use roots blower air into the gas pipeline, the gas pipeline will be sent to the air into the microporous tube, and the microporous tube will be dispersed into the water in the form of micro-bubbles air micro Bubbles float upward from the bottom of the pool, bubbles in the gas under the action of high partial pressure of oxygen, oxygen is fully dissolved into the water, but also cause the rotation of the water flow and up and down flow, the up and down flow of the water flow will be the upper layer of oxygen-rich water into the bottom, at the same time the rotation of the water flow will be the microporous tube around the oxygen-rich water outward diffusion, to achieve the uniformity of the pool water to increase the oxygenation.

Oxygen Generator for nursery

Advantages:

5.1. Power saving. The bottom of the microporous oxygenator pressure width, simple structure, easy maintenance, long service life, and the whole machine vibration is small. Practice has proved that the underwater aeration oxygenation effect is good, compared with the traditional oxygenation method, to achieve the same effect, you can save electricity 60 ~ 80%. A 3HP blower, effective oxygenation of the water surface for 2-3 hectares;

5.2 it improves the ecological environment of aquaculture water. Aeration and oxygenation at the bottom of the water body to produce a wide range of bubble flow, sufficient airflow, and large surface contact, can ensure that the bottom of the water body of dissolved oxygen in the 6.5 mg / l, to accelerates the bottom of the water body of organic matter and nitrite deposited in the oxidative decomposition of hazardous substances and can be harmful to toxic gases out of the water surface, thereby improving and stabilizing the quality of the water, for the fish vannamei to create a suitable environment for the growth of the fish, can reduce the occurrence of diseases. The occurrence of disease;

5.3 it is in favor of high-density breeding. Aeration oxygenation for the static bottom of the water to increase oxygen, the entire body of water effective dissolved oxygen is sufficient to improve the water body of the various layers of space culture object's ability to increase appetite, shorten the breeding cycle, to increase the biological load of the water body to create the conditions;

5.4 it is easy to use. Different water surface areas can be configured with different power of the fan, a fan can practice double-pond oxygenation or multi-pond oxygenation, and the main pipe, branch pipe connection is easy to replace;

5, in the water, will not leak. Compared with the traditional oxygenator, the bottom of the microporous oxygenation is piping in the water, and with the motor on the shore, there is no possibility of leakage in the water.

Disadvantages:

5.1 the first investment in the capital relative to the impeller type and other oxygenators, the cost is high;

5.2the current level of microporous technology is limited, and the production of aeration tubes, is easy to clog;

5.3 it is not suitable for deep-water ponds, generally more than 1.5 m -2.0 m water depth, pond water pressure is too high can not play a good oxygenation effect.

6. swell aerator swell aerator #water treatment

Principle: The working principle of the surge aerator is to use the floating body impeller to lift the water in the center and resonate to cause water waves to spread around.

Advantages:

6.1simple design, lightweight, power saving.

6.2 the water is not easy to use. 3, to improve the sunlight on the water body;

6.3 Improve the light intensity of the sunlight on the water body and the air-liquid contact area, promote the growth of algae, give full play to and utilize the pond's ecological oxygenation capacity;

6.4 better weather in the case of stronger oxygenation capacity

Disadvantages:

6.1 the pond is shallow surge is too large easily stirs up the water, and can not be used;

6.2 The oxygenation effect is not high in cloudy and rainy days.

Brushless DC Inverter Paddle Wheel Aerator

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