Roots Blower It is a positive displacement fan, and the air volume delivered is proportional to the speed. Two impellers suck and exhaust three times every time the three blade impeller rotates. Compared with the two blade impeller, the gas pulse is less, the load changes less, and the mechanical strength is high. Two three blade impellers are set on the two parallel shafts. There is always a small gap between the wheel and the inner hole surface of the elliptical case and between the three impellers. Because the impellers rotate at a constant speed in opposite directions, a certain amount of gas surrounded by the case and the impeller is transported from the suction side to the discharge side. Each impeller is always kept in the correct phase by the synchronous gear, which will not touch each other, so it can be high-speed, does not need internal lubrication, and has simple structure, stable operation, stable performance, suitable for a variety of purposes, and has been used in a wide range of fields.
Usually, the Roots blower and water pump on the sewage treatment system are operated at a constant speed by the motor, and then the air volume is adjusted by changing the opening of the valve at the outlet of the blower or the water supply is adjusted by changing the opening of the regulating valve on the outlet pipeline of the water pump. The biggest feature of fans and water pumps is that the load torque is proportional to the square of the speed, while the shaft power is proportional to the cubic of the speed. Therefore, if the constant speed operation of the motor is changed to adjust the speed of the motor according to the required flow, a large amount of power can be saved. In the sewage treatment system, the main function of Roots blower is to flush oxygen for the biochemical system, so that the biochemical system has sufficient oxygen. We put an online dissolved oxygen meter in the biochemical tank, set the oxygen content required in the water on the dissolved oxygen meter, send the data of the online dissolved oxygen meter to the PLC, and the PLC controls the inverter, and then the inverter controls the Roots blower, which has obvious effects. We know that the wind pressure of Roots blower is not limited by the fan speed, and the wind pressure can remain unchanged no matter how the speed changes. The air volume is proportional to the fan speed, i.e. Q=KN
Q: Represent air volume N: Represent fan speed K: Represent coefficient
It can be seen from the formula that the air volume regulation is achieved by changing the motor frequency completely by the frequency converter to achieve stepless speed change, which has the effect of adjusting the air volume. According to the lowest frequency of 15HZ of the process fan applied on site, it is usually about 35HZ. In some cases, 50HZ operates with full air volume. Since the biochemical system processes are basically the same, the air volume regulation in different biochemical systems is basically the same. Therefore, the application of frequency conversion technology can achieve about 40% energy saving effect.
Roots blower is a constant torque load, and its power saving rate is in direct proportion to the speed drop, that is, N%=△ N%. Although it is different from ordinary fans and pumps, its power saving rate is higher, and as long as the aeration system in the biochemical tank is not bad, it works continuously, and the starting time is also very long, so it has great power saving potential and high power saving costs.
After the technical transformation of Roots blower, the production mode of adjusting the air pressure or air volume by adjusting the size of the outlet valve has changed. The labor intensity is reduced, the adjustment is timely, and the energy consumption of a single machine is significantly reduced. The inverter has the following advantages after the energy-saving transformation of the fan: 1. Improve the power factor and reduce the reactive power loss; 2. The inverter control has the function of automatic energy-saving control, which can automatically adjust the voltage and frequency according to the load conditions, so that the motor can operate at the highest efficiency; 3. The frequency converter has advanced magnetic flux vector control, low frequency output rated torque, and can implement strong control on Roots blower; 4. Save and reduce operation cost; 5. Realize soft start and no large current impact during startup; 6. Prolong the service life of Roots fan. In the sewage treatment system, various pumps also need energy conservation. We can use frequency converter control according to the needs of the process to achieve the purpose of energy conservation. At the same time, when installing pumps, we should also pay attention to the following points to achieve the purpose of energy conservation.
1、 Adjust the axial clearance to prevent the impeller ring and axial clearance from being inappropriate. When using, it should be adjusted according to the factory instructions of the pump.
2、 Timely remove pipe blockages. Foreign matters left in the inlet pipe, impeller or flow passage of the guide housing will reduce the water yield.
3、 Prevent the water pump from entering the air. When air is fed into the water pump, the water output will be significantly reduced, and the sealing parts should be inspected and maintained.
4、 The use of coupling direct transmission instead of flat belt can improve transmission efficiency.
5、 In some places, the bottom valve shall not be used if possible
6、 Select a reasonable installation position, reduce elbows, and make the water outlet face the pool.
7、 Shorten the line.
8、 Enlarge the outlet pipe diameter.
9、 The water can be removed when it can be kept clean.
