What is Air Blower?
The air blower is mainly composed of the following six parts: motor, air filter, blower body, air chamber, base (and oil tank), drip nozzle. The blower operates eccentrically on the rotor offset in the cylinder, and changes the volume between the blades in the rotor slot to suck in, compress, and discharge air. During operation, the pressure difference of the blower is used to automatically send the lubrication to the drip nozzle and drip into the cylinder to reduce friction and noise, while keeping the gas in the cylinder from returning. This type of air blower is also called a sliding vane blower. There are many types of air blowers, mainly divided into the following categories.
- Root blower
Root blower is a positive displacement blower, which is a type of rotary blower, which uses two blade-shaped rotors or three blade-shaped rotors to move relative to each other in the cylinder to transport gas. Due to the continuous rotation of the rotor, the pumped gas is sucked from the air inlet into the air between the rotor and the pump casing, and then discharged through the exhaust port. There is no internal compression process for the gas through the Roots blower.
Root blowers are commonly used blowers in small and medium sulphuric acid plants. When the required air volume is small, centrifugal blowers are often unsuitable due to the small diameter of the impeller, which is generally difficult to reach the pressure head required for sulfuric acid production at a speed of 2950 rpm. Root blowers have the advantages of both reciprocating compressors and centrifugal air blowers. When the speed of the reciprocating compressor is constant, the air pressure changes slightly, and the air supply volume can be kept unchanged, that is, to maintain the proportional relationship between the speed and the air volume. It also has the advantages of high speed of centrifugal blower, no need of air valve and crankshaft, lighter weight and convenient application. The disadvantage is that when the outlet is blocked, it is easy to increase the pressure and even cause damage to the machine itself. After being used for a long time, the air supply decreases due to the expansion of the gap between the two rotors and the gap between the rotor and the casing.
- Blast furnace blower
The current blast furnace blowers all use blade fans, mainly centrifugal and axial flow. The centrifugal air blower has the advantages of simple structure, reliable operation, high design point efficiency and low noise. Centrifugal blast furnace blowers have relatively mature manufacturing and use experience in China, and blast furnaces below 400m3 are widely used in industrially backward regions and countries.
- Magnetic levitation blower
Magnetic levitation blower is a type of turbine that uses magnetic levitation bearings. The main structure is that the blower impeller is directly mounted on the extended end of the motor shaft, and the rotor is suspended vertically on the active magnetic bearing controller, without the need for speed increaser and coupling, and is directly driven by a high-speed motor. The core of the single-stage high-speed centrifugal blower controlled by the frequency converter is the technology of magnetic suspension bearing and permanent magnet motor. The magnetic levitation blower has the advantages of energy saving, high efficiency, high system integration and high cooling efficiency.
- Single-pole high-speed centrifugal blower
The unipolar high-speed centrifugal blower is a product developed in the 1990s with the application of the "three-dimensional flow theory" in the design of centrifugal compressors and blowers. The unipolar high-speed centrifugal blower adopts the ternary flow design theory in the design, so that the efficiency of the unipolar centrifugal blower is as high as 82%, which is much better than that of the multi-pole centrifugal blower. The axial inlet guide vane adjustment device is adopted in the structure. Under constant pressure, the flow is adjusted to 65%~105% of the rated current, and the flow adjustment range of a single unit is 45%-100%, which makes it run under low load conditions with higher efficiency. This is a low-speed multi-pole blower and Roots Advantages that the blower does not have. Due to its small size, light weight, high efficiency, energy saving, wide adjustment of performance range and high level of automation, the unipolar high-speed centrifugal blower has become the mainstream product of aeration blowers in the sewage treatment industry.
- Multi-stage centrifugal blower
Centrifugal blower is also called turbo blower. Under the action of the rotating impeller, the gas obtains an increase in pressure and flow rate, which can realize continuous air supply. Its working principle is that when the motor rotates to drive the fan impeller to rotate, the gas is thrown out under the action of centrifugal force and the flow direction is changed. The kinetic energy is converted into static pressure energy, and the gas is discharged from the exhaust port. At the same time, a certain negative pressure is formed between the impellers to make the outside world. The gas is added under the action of atmospheric pressure to achieve the purpose of continuous blowing. Centrifugal blowers are divided into multi-stage centrifugal blowers and single-stage centrifugal blowers according to the number of impellers.
Compared with roots blowers, low-speed multi-stage centrifugal blowers have the advantages of lower noise, stable and reliable operation, and higher efficiency. Since the 1980s, they have gradually replaced roots blowers in foreign sewage treatment plants, but they still There are disadvantages such as large volume, heavy weight, poor flow regulation performance, low efficiency, and high energy consumption.
- Air suspension centrifugal blower
Air suspension centrifugal blower is a brand-new concept centrifugal blower. It draws lessons from the turbine engines of aviation and spacecraft, applies advanced air suspension technology, and adopts two high-end core technologies of "high-speed direct-connected motor" and "air suspension bearing". The speed gear coupling, cooling system and oil lubrication system of the traditional single-stage high-speed turbo blower are improved, which greatly improves the technical performance and operational reliability of the product.