The reasons and treatment methods of ventilator asthma
Generally speaking, high -pressure small flow fans are more prone to surge than low -pressure large flow fans. The product can be measured by experimental methods. The pressure rises to an air replacement fan of 500 ~ 1000Pa, and the surge flow generally accounts for 50%of the design flow.
The sound of breathing is very harmful to the ventilator. When the waves occur, due to the pulsation and periodic vibration of strong airflow, the noise is intensified, which will not only greatly increase the leaves of the impeller, but also have a significant impact on the impeller welding and connecting rivets. In addition, the axial force of the main shaft and bearing, bearing, and bearing seats will increase significantly, causing direct damage to the impeller, the spindle, the bearings, the bearing seat and the foundation.
Observe the pressure and traffic of the ventilator exit. When the ventilator runs under stable conditions, the export pressure and the import flow are not greatly changed. It is regular. The measured data shakes near the average, and the range of fluctuations is small. When it is close to breathing, both have undergone tremendous changes.
Observe the vibration of gas and bearings. When it is close to breathing, a strong vibration will occur in the fan bearing seat, and a strong vibration will occur in the export pipe.
1. When choosing a blossom, its performance should be within high efficiency zones.
Don't artificially increase the optional coefficient to ensure that the actual traffic of the fans in actual operation is much higher than the design flow. Using a large number of throttle can easily adjust the fan to the surging area.
To this end, in the design and selection of fan, ensure that the range of working conditions is not close to the surging area. For example, in the selection of circulating fluidized bed fans, the general design institute provides two parameter points TB and BMCR. TB is a boiler load point. The BMCR point is the design and operation point. The performance of the TB point uses 15%-30%of the BMCR point. Both options need to consider the fan into a stable working area from the BMCR point to reach the TB point.
This enables the BMCR dot to run at high -efficiency areas, and the blower is usually not running at this point, so the TB point is placed in a low -efficiency area. Therefore, it is particularly important to master and understand the purpose of the book.
2. If the fan is surging during the system operation, you can also adjust the range of work by changing the fan speed.
The centrifugal ventilator can change the diameter of the impeller. Axial circulation fan can change the angle of the dynamic leaf installation. Through this method, the performance curve of the ventilator can move to a small traffic area. Then, the Langyong boundary line also moved to a small traffic area accordingly. This can also expand the scope of stability of the ventilator. 3. Some units do not have the above -mentioned regulatory conditions. They cannot stop and affect production. Therefore, there is a simple and fast adjustment method to eliminate the surge. It is the storm snow valve.
If Q = Q is added with Q book paper greater than qmin, you can remove the book immediately. However, it is pointed out that the atmospheric gases are harmless gases. If there is harmful gases, flow from small pipelines into the inlet pipeline of the ventilator. The disadvantage of this method is to release part of the momentum obtained through the impeller to reduce the overall efficiency of the fan. However, this method is simple and effective, so it is widely used in ventilation regulations.
4.2 Valve operation method.
Install two valves on the exhaust pipe of the ventilator, and fix the volume between the two valves at a specific value. The volume between the two valves is equivalent to one gas cylinder. Slotting valve can prevent waves from surging. The two valves are used as a resistance. Practice has proved that the device can not only achieve stable operation of the system, but also help reduce noise.
This method is a solution to prevent axis circulation fans, and has been widely used in some foreign fan manufacturing plants. In addition, adding an asthmatic leaf grids to the top of the main fan's blades can deviate from the surging border of the ventilator to the small traffic area and expand the scope of the stable work of the ventilator. The above is the reasons and treatment methods of the ventilator. If you need to learn more, please contact us at any time!