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The "lateral canal" or "peripheral canal" blower
This type of blower, which has only recently been developed, is perfectly adapted to the aeration of small tanks, with a pumping pressure of around 0.2 bar (2 m water pressure) in single stage and 0.5 bar in two stage operation, and the flow reaches 1000 m3/hour. These devices are uncomplicated and have a simple mechanical construction charged, with a guarantee of sturdiness: one wheel is directly driven by a motor at 3000 t/min. as with an aerator. The seemingly light construction is however justified by good quality manufacture. Upon installation, the usage characteristics must be well defined because an adaptation error can put the engine into overload and thus overheat the blower to cause it to jam. In use, the maintenance is limited to consistent care of the filtration (with particular attention to seawater, as salt accumulation can block the filter). On the other side of the coin, for this well working, good quality machine, there is a particularly poor yield in compression. The energy consumption can become costly for a high rate of flow. An economic comparison study with other types of blower is therefore essential. |
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The “Roots” blower (called 'rotary piston machine’)
| This is a ‘volumetric’ type device. That is to say that in a mechanical way, it mechanically isolates volumes of gas to compress them. Two ‘bean-shapes’ lobes rotate in contraflow on a weak action stator with one of the lobe shafts driving the second via gears outside of the compression chamber. When the delivery and pressure necessary for the oerafion of a tank have been determined, the question of the choice of the best adapted compression means remains. There is a wide range of equipment for different applications and it is important to select the appropriate one. This type of blower has a very large flow range. greater than 10 000 m3/h and pressures of 1 bar (that is 10 m of water pressure). In practice, a limit of 0.8 bar is often recommended. These machines which are more complex than the previous ones, are however very reliable and require little maintenance. However, an overload can cause overheating, and abnormal contact between the lobes and stator can cause unreparable damage to the machine. Like all volumetric machines, in the event of faulty operation, the pumping pressure can become very high so that it's necessary to fit a safety valve. “Roots” blowers are quite noisy, despite the installation of silencers. Once the flow and the pressure necessary to aerate the tank have been determined, there is the question of the best-adapted means of compression. There is a wide range of devices which cover all areas of application and it is important to choose well. Their practical output, although better than the blowers with peripheral canals, is stiil mediocre, at around 65 %. |
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To contact AQUALOG |
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The "centrifugal" blower
It is the centrifugal blower, which has improved characteristics to the point of obtaining a pressure over 0.7 bar. This is the machine that is recommended for large outputs from about 5000 m3/hr to beyond 100.000 m3/hr. Their efficiency of between 0.78 and 0.8, is excellent. Their apparent working simplicity hides, in fact, sophisticated technology as the rates of rotation and peripheral wheel speeds are quite high. Their use is essential for the aeration of very large basins and tanks because of their energy economy. The three types of machines described above are “non-lubricated" and therefOre deliver air that is free from oil vapour, which can be used directly for tank aeration. There are many other types of machine but, they are adapted for more minor applications than tank aeration. TheSe are, briefly: - the evacuation pumps or compressors with blades which have a very large range of flow and pressure (flow: 1 to 10.000 m3/hr, pressure 20 bars) have very varied applications such as vacuum packed fish products. Some versions are not lubricated. - the lubricated or non-lubricated piston compressors. - and also the range of screw compressors discussed, lubricated or non-lubricated, particularly for “industrial air” at 7 bars. This list shows the range of various means of air compression and the importance of closely studying the type and features of the compressors when setting up an aquaculture system. |
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Paddle Compressor
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This machine works in the same way as the suction pump. Flow of 5-6300 m3/h PressUre : from vacuum to 20 bars Particutarly recommended for biogas |
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Compressed air without a trace of oil
To provide hygiene, security and economy, these compressors produce compressed air completely Without oil. 24-hour use and compact, quality ISO 9001 and low sound levels. 8 or 10 bar: Non-lubricated spiral compressors. Flow 10-48 m3/hr. 8.6 max. bar: Non-lubricated lobe compressors: Flow 0f 130-315 m3/hr 0.5-2.5 bar: Non-lubricated lobe compressors: Flow of 470-830 m3/hr. Other available ranges: piston compressors and screw compressors. |
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Aqualog
Bouée Borha
Corniche du Bois Sacré
Marépolis Est
83500 La Seyne sur Mer
Tél. : 04 94 10 26 26
Fax : 04 94 10 26 30
