Roots Rotary Lobe Blower , Tri Lobe Air Blower With Brushless DC Electric Motor

Roots air blower tri lobe roots blower roots rotary blower carbon steel material brushless dc electric motor

Roots blower basic principle

1. Roots blower is a volume rotary blower.

This kind of compressor relies on synchronous gears at the shaft end of the rotor to keep the two rotors engaged. Each concave curved surface part of the rotor and the inner wall of the cylinder form a working volume, which takes away the gas from the suction port during the rotation of the rotor. When it moves to the exhaust port and is connected to the exhaust port, the pressure in the working volume rises suddenly because of the gas reflux with higher pressure, and then the gas is transported to the exhaust channel. The two rotors are not in contact with each other, and they are sealed by tightly controlled gaps, so the discharged gas is not contaminated by lubricating oil. 

2. The selection of roots blower 

In sewage plant, model selection of the blower fan manufacturer product samples are given on the standard of performance parameters of the inlet conditions, fan in be used actually is not a standard status, however, when the blower environmental conditions such as temperature, atmospheric pressure and altitude is not at the same time, the performance of the fan will also change, will not be able to direct use of model selection of the design product based on the performance parameters of the samples, However, it is necessary to convert the performance requirements of the fan into the fan parameters under the standard intake state to select the model according to the actual use state.

The level of the exhaust pressure of the volumetric blower does not depend on the fan itself, but on the situation of the device after the gas is discharged by the blower, that is, the so-called "back pressure". The aeration blower has the characteristics of forced gas transmission. The exhaust pressure marked on the blower nameplate is the rated exhaust pressure of the fan. In fact, the blower can work at any pressure below the rated exhaust pressure, and can also work beyond the rated exhaust pressure as long as the strength and exhaust temperature allow.

For sewage treatment plants, the absolute pressure (back pressure) generated by the exhaust system is the sum of the pressure loss value of the pipeline system, the water depth of the aeration pool and the ambient atmospheric pressure. (roughly, the water depth plus one meter)

3. Air volume (oxygen demand)

When calculating the oxygen demand of sewage treatment, the result is the mass flow rate of oxygen required under the standard state QM (kg/min), and then it is converted into the volume flow rate of air required under the standard state QV1 (m3/min). If the blower is not used in the standard state, such as when it is used in the plateau area, the air density and moisture content will change. The volume flow rate of air supplied by the blower is the same as the standard state, and the mass flow rate of the air supplied will be reduced, which may lead to insufficient oxygen supply. The simplest calculation method is to calculate a square of four aeration heads according to the area of the sewage pool, and the air supply of each aeration head is 0.03m3/min (0.03 here is the middle value of the aeration head).

4. The difference between winter and summer

Blower selection should pay attention to the change law of air supply flow rate of the blower. For the same blower, in winter and summer, its volume flow rate will not change, but due to the different air density, the mass flow rate will change, that is to say, the oxygen supply will be different. This is due to the decrease of winter temperature and the increase of air density, so the mass flow rate of dry air supplied by the fan is greatly increased compared with the standard state, which causes the increase of oxygen supply. From the actual measurement of operation, the dissolved oxygen of the aeration pool in winter every year will be 1 ~ 3mg/L higher than that in summer.

Therefore, in the process of production operation, it is necessary to adjust the equipment in time for this change, so that the oxygen filling capacity of the blower is compatible with the oxygen demand in the actual operation. For Roots blower, the use of frequency converter, by changing the fan speed to adjust the air supply is very economical and practical.

 
Key Features 

• Impeller diameter: 90~3500 mm 
• Speed of mainshaft: 560~2900 rpm
• Pressure range: 3000~25425 Pa
• Flow range: 1297~83305 m3/h
• Air Temperature: 20~1000 Celsius degree

• Material: Cast Iron, Carbon Steel, Stainless Steel.

• Efficiency: 80%-90%

Please advise us the USAGE and following Parameter.Our engineering Dept will recommend the most suitable product for you.