Roots blower belongs to positive displacement blower, which is a kind of rotary blower. 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. The gas passes through the Roots blower without internal compression.
Roots Blower
Roots blower belongs to positive displacement blower, which is a kind of rotary blower. 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. The gas passes through the Roots blower without internal compression.
Roots blower is a commonly used blower in small and medium-sized sulfuric acid plants. When the required air volume is small, the centrifugal blower is often unsuitable due to the small diameter of the impeller, and it is generally difficult to achieve the pressure head required for sulfuric acid production at a speed of 2950 rpm. Roots blower has the advantages of both reciprocating compressor and centrifugal blower. It has the characteristics that the air pressure of the reciprocating compressor changes slightly when the rotation speed is constant, and the air supply volume can remain unchanged, that is, the proportional relationship between the rotation speed and the air volume is maintained. , It also has the advantages of high rotational speed of centrifugal blower, no valve and crankshaft, light 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 a long period of use, the air supply volume will decrease 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 are all blade-type fans, which are mainly divided into two categories: centrifugal type and axial flow type. The centrifugal 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 backward industrial regions and countries. However, with the increase of the blast furnace, the adjustment loss, external dimensions and weight of the centrifugal blower have increased significantly, which brings great difficulties to manufacturing, transportation, installation and maintenance, and is also affected by Rotating parts - the limitation of impeller material strength, main shaft rigidity, motor start and other factors reduces the reliability and economy of the fan operation. The axial flow blower has the characteristics of compact structure, small size, light weight, good load regulation, wide application range, small rotational inertia of the fan, and easy start of the motor, so it is widely used in large-scale and modern blast furnaces. China has widely used axial flow blowers in blast furnaces over 500m3, and has accumulated certain experience in manufacturing and operation.
Magnetic levitation blower
Magnetic levitation blower is a type of turbine using magnetic levitation bearings. Its main structure is that the blower impeller is directly installed on the extension end of the motor shaft, and the rotor is vertically suspended on the active magnetic bearing controller, without the need for a speed increaser and a coupling, and it is directly driven by a high-speed motor. The single-stage high-speed centrifugal blower whose speed is regulated by the frequency converter, its core is the technology of magnetic suspension bearing and permanent magnet motor. The main technical features of the magnetic levitation blower are:
(1) High-efficiency impeller: The high-efficiency impeller is designed with ternary flow, and the five-axis machining technology ensures the manufacturing accuracy of the impeller.
(2) Magnetic bearing: no mechanical wear, low energy, semi-permanent life.
(3) Integration of structural design: The fan impeller is directly installed on the shaft end of the motor, and is integrated with the control system. It is assembled in the box, and the structure is simple and concise.
(4) Convenient installation and maintenance: no need for lifting equipment and tall space, no special foundation, convenient maintenance, and saving the infrastructure cost of the machine room.
(5) Modular design of the system: According to the different flow of users, multiple blowers are allowed to work in parallel, with a wide adjustment range and strong flexibility.
The advantages of magnetic levitation blower:
(1) Energy saving and high efficiency: The magnetic suspension bearing is adopted, without contact loss and mechanical loss, and realizes the stepless speed change adjustment of high speed.
(2) High system integration: It has imported filters, cooling systems, fully automatic anti-surge systems, power failure and fault protection systems, etc., which bring operational safety, convenience and reliability. [6]
(3) High cooling efficiency: The cooling system adopts an external condenser, which can effectively protect the fan system and realize the start and stop of the fan at any time.
Single pole high speed centrifugal blower
The single-pole high-speed centrifugal blower is a product developed in the 1990s with the application of the "ternary flow theory" in the design of centrifugal compressors and blowers. The single-pole high-speed centrifugal blower adopts the ternary flow design theory in the design, so that the efficiency of the single-pole centrifugal blower is as high as 82%, which is much better than that of the multi-pole centrifugal blower. 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 operate with high efficiency under low load conditions. This is a low-speed multi-pole blower and Roots Advantages that the blower does not have. Due to the characteristics of small size, light weight, high efficiency, energy saving, wide performance range adjustment and high automation level, the single-pole high-speed centrifugal blower has become the mainstream product of the aeration blower in the sewage treatment industry.
Multistage centrifugal blower
Centrifugal blower is also called turbine 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 changes the flow direction, the kinetic energy is converted into static pressure energy, the gas is discharged from the exhaust port, and 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 blasting. Centrifugal blowers are divided into multi-stage centrifugal blowers and single-stage centrifugal blowers according to the number of impellers. A multi-stage low-speed centrifugal blower normally refers to a centrifugal blower with two or more impellers connected in series on the same main shaft, with at most eight stages of fan blades and a rotor speed of 3000~3600r/min. Centrifugal blowers generally use inlet throttling to adjust flow and pressure, so that the fan can run at a lower power, without air regulation, and can maintain the same high efficiency as the rated operating condition, and is used for unstable pressure and flow conditions. .
The air supply volume of the multi-stage centrifugal blower is generally large, but the air pressure generated is not high, the outlet gauge pressure is generally ≤110kPa, and the flow rate is generally about 130m3/min. Compared with the Roots blower, the low-speed multi-stage centrifugal blower has the advantages of lower noise, stable and reliable operation of the fan, and higher efficiency. Since the 1980s, the Roots blower has been gradually replaced in foreign sewage treatment plants, but still There are disadvantages such as large volume, heavy weight, poor flow regulation performance, low efficiency, and large energy consumption.
Air Suspension Centrifugal Blower
Air Suspension Centrifugal Blower is a brand-new concept of centrifugal blower. It draws lessons from the turbine engine 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, and the technical performance and operational reliability of the product are greatly improved.
The air suspension single-stage centrifugal blower is made of SVS titanium alloy material, the impeller has strong deformation resistance, and the best efficiency angle design is selected, and the efficiency is as high as 88%. It is a new type of motor developed with the development of control technology, which is more efficient and energy-saving; the frequency conversion adjustment method is adopted to make the adjustable range of the suspended centrifugal blower wider; the air self-cooling technology can ensure that the blower remains reliable in hot summer. Due to the use of high-speed direct-coupled motors, air suspension bearings and three-dimensional simulated turbine impellers, the energy consumption caused by mechanical transmission and mechanical friction is greatly reduced, so the efficiency is extremely high; air suspension bearings have a longer life than magnetic suspension bearings. The replacement price is also relatively low; the start and stop does not depend on the power supply, and the operation is more stable and reliable than the magnetic levitation centrifugal blower; compared with the Roots blower, it can save 25%~35% of energy, and compared with the traditional multi-stage centrifugal blower, it can save energy by 15%~20% %, compared with the traditional single-stage high-speed centrifugal blower, it can save energy by 10% to 15%. The air volume is 35~160 m3/min, and the maximum outlet air pressure is 100kPa.