Structure and composition of blower

Impeller machinery is a device that transfers energy to continuous flowing fluid by the dynamic action of rotating blades on the impeller or drives blades to rotate by the energy from the fluid. In turbomachinery, rotating blades do positive or negative work on the fluid to increase or decrease the pressure of the fluid. Impeller machinery is divided into two categories: one is working machine, from which fluid absorbs power to increase head or water head, such as vane pump and fan; The other is prime mover, in which fluid expands, reduces pressure or water head to generate power, such as steam turbine and water turbine. People call the prime mover turbine, and turn the working machine into vane type fluid machinery.

According to the different working principles of fans, they can be divided into two categories: blade type and volumetric type, among which blade type can be divided into axial flow type, centrifugal type and mixed flow type. According to the pressure generated by the fan, it can be divided into blower, compressor and ventilator. According to the current mechanical industry standard JB/T2977-92, fan refers to the fan whose outlet pressure (gauge pressure) is less than 0.015MPa when the inlet is standard air inlet; The blower is called when the outlet pressure (gauge pressure) is between 0.015MPa and 0.2MPa; The outlet pressure (gauge pressure) greater than 0.2MPa is called compressor.

The main components of the blower are: volute, flow collector and impeller.

The collector can guide the gas to the impeller, and the inlet air flow condition of the impeller is guaranteed by the geometry of the collector. There are many kinds of collector shapes, mainly including: cylinder, cone, cone, arc, cylinder arc, arc cone, etc.

The impeller is generally composed of four parts: wheel cover, wheel disc, blade and shaft disc. The connection mode of its structure is mainly welding and riveting. According to the different installation angles of the impeller outlet, it can be divided into three types: radial, forward and backward. The impeller is the most important part of the centrifugal fan, driven by the prime mover, and the heart of the centrifugal impeller machine. It is responsible for the energy transmission process described by the Euler equation. The flow inside the centrifugal impeller is affected by the impeller rotation and surface curvature, and is accompanied by flow separation, reflux and secondary flow, which makes the flow inside the impeller very complex. The internal flow condition of the impeller directly affects the aerodynamic performance and efficiency of the whole stage and the whole machine.

The volute is mainly used to collect the gas from the impeller. At the same time, it can convert the kinetic energy of the gas into the static pressure energy of the gas by appropriately reducing the gas speed, and guide the gas to leave the volute outlet. As a fluid impeller machine, blower is a very effective method to improve its overall performance and working efficiency by studying its internal flow field. In order to understand the real flow condition inside the centrifugal blower and improve the impeller design and volute design to improve the performance and efficiency, scholars have done a lot of basic theoretical analysis, experimental research and numerical simulation for the centrifugal impeller and volute.

Other structures of the blower:

Rotor: composed of shaft, impeller, bearing, synchronous gear, coupling, shaft sleeve, etc.

Bearing: 3000 double row centripetal spherical roller bearing is selected as the locating end near the coupling end. As the free end, the near gear end selects 32000 single row radial short cylindrical roller bearing to adapt to the axial displacement of the rotor during thermal expansion.

Synchronous gear: It is composed of gear ring and hub, which is convenient for adjusting impeller clearance.

Engine body: it is composed of the casing and left and right wallboards. The left and right wallboards, bearing seats and sealing parts installed in the left and right wallboards can be mutually used.

Base: medium and small fans are equipped with a common base, while large fans are only equipped with a fan base, which is convenient for installation and debugging.

Lubrication: gear is immersed, and bearing is splash lubricated. Good lubrication effect, safe and reliable.

Transmission mode: direct coupling is the main mode. If required by performance specifications, the V-belt pulley speed change mode can also be selected. Elastic coupling shall be selected to mitigate impact and compensate a small amount of axis deviation. Except that the motor is used as the driving machine for large flow fan, steam turbine or other driving machines can also be used.