Roots fan is a volumetric fan. The air flow is proportional to the rotational speed. The three-blade impeller is sucked and exhausted three times by two impellers every time it rotates. Compared with the two-blade impeller, the gas pulsation becomes less, the load changes less, the mechanical strength is higher, the noise is lower and the vibration is smaller. There are two three-blade impellers on two parallel axles. There is always a small gap between the wheel and the orifice in the elliptical box and each impeller. Because the impeller rotates in the opposite direction and uniformly, a certain amount of gas surrounded by the box and impeller is transported from the inhaled side to the exhausted side. Each impeller keeps the correct phase from the synchronous gear all the time, and does not touch each other. Therefore, it can be high-speed without internal lubrication, and has simple structure, stable operation, stable performance and adaptability to various uses. It has been used in a wide range of fields. In short, its working principle is: the top of the rotor is like the moment when the exhaust outlet line opens, the high-pressure air of the exhaust outlet can be reversed and compressed. This countercurrent and compression produce drastic pressure changes. This pressure change causes the noise of the fan.
Roots blower is a kind of volumetric rotary blower. Its principle is that when air passes through the muffler into the blower, the two impellers in the casing will keep a certain gap between each other. Then Roots blower will drive the equal speed reverse rotation through the synchronous gear, push the inhaled gas from the inlet to the outlet, and overcome the resistance of the high pressure gas at the outlet side by phase method, and pass through the exhaust muffler. Safety valves and other forced exclusion units, ultimately to achieve the purpose of conveying gas.
From the point of view of use, when the Roots blower fan starts, there is no need to install valves at the intake, while the centrifugal blower must close all the inlet valves and install energy-saving valves at the intake. Moreover, Roots blower and centrifugal blower must adjust the air volume by adjusting the rotational speed. The larger the adjusting range, the smaller the centrifugal blower can adjust by adjusting the intake valve. It should be noted that after the selection of the centrifugal blower model, the boost will be fixed, and the overpressure can not be used. If the pressure is found to be low in the use process, the blower can not be used by increasing the power of the motor. When the pressure selected by Roots blower is not the maximum allowable boost of the blower, the use pressure of the blower can be increased by increasing the power of the motor. Power. In addition, from the point of view of performance characteristics, Roots blower has the characteristics of hard exhaust when the pressure becomes smaller and the flow changes very little. When the pressure of centrifugal blower varies, the flow rate varies greatly. From the price point of view, small flow blower, Roots blower than centrifugal blower has greater advantages.
1. Fans can be classified into several types according to the material used, such as iron shell fans (ordinary fans), FRP fans, plastic fans, aluminium fans, stainless steel fans, etc.
2. The fan can be divided into centrifugal, axial, oblique (mixed) and cross-flow types according to the direction of flow after the air enters the impeller.
3. Fans can be divided into pressure-type local fans (hereinafter referred to as pressure-type fans) and flameproof motors which are placed outside or inside the runner and flameproof motors which are placed in the flameproof sealed chambers (hereinafter referred to as extractive local fans).
4. Fans can also be divided into single-stage, double-stage or multi-stage pressurized fans according to the form of pressurization. Roots fans are multi-stage pressurized fans.
5. Fans can be divided into: axial flow fan, mixed flow fan, Roots blower, roof fan, air conditioner fan, etc. according to the purpose.
6. Pressure of fan can be divided into low pressure fan, medium pressure fan and high pressure fan.
7. Classified according to different uses: ordinary Roots blower; negative pressure Roots blower; Roots blower for special gases.
The negative pressure Roots blower is mainly used for vacuum packaging and other pumping purposes, while the special gas Roots blower is mainly used for conveying inflammable and explosive gases such as natural gas and gas. The sealing mode is piston ring seal, which can ensure zero leakage.
8. According to the different classification of impellers: two-blade Roots blower; three-blade Roots blower.
Roots blower was first used with two-blade type. With the renewal of technology, the three-blade roots blower gradually replaced the two-blade roots blower with the air volume below 130 m3/min, but the two-blade roots blower was still used over 130 m3/min.
Note: The impeller of a fan has three blades called a three-leaf Roots blower and two blades called a two-leaf Roots blower.
9. According to different cooling modes, they are classified as air-cooled Roots fans and water-cooled Roots fans.
When the pressure is below 65KPA, air-cooled Roots blower is selected, and water-cooled Roots blower is selected when the pressure is above 65KPA.
10. According to the structure of fan, it can be classified as single tank type, double tank type and dense type.
When the pressure is below 50 KPA, single tank type is chosen, and double tank type is chosen when the pressure is above 50 KPA. The dense roots blower covers a small area. The outlet of the blower is below the blower. The outlet muffler is connected from the bottom of the blower. The outlet is placed horizontally with the ground. Intensive selection is generally specified for customers.
Food vacuum package blower
Roots blower for flour industry
No comments:
Post a Comment