Changes in air pressure
Thread Content
At the site, a blower is used to force cooled air into the furnace. Due to an incorrect calculation in the selection of the blower, the inlet air pressure became too high, reaching 8 KPa, whereas it should be around 4000 KPa. The diameter of the pipeline is 133, while the diameter of the furnace is 1000. Will such a high pressure of air at the pipeline inlet affect the pressure inside the furnace? What is the air pressure once it enters the furnace? How to calculate it? The pressure inside the furnace is maintained at a negative level by the exhaust fan in the system located at the rear of the furnace. At present, the air volume supplied by the blower is not at full capacity; so how will the furnace pressure change once it operates at full capacity?
1、4kpa； 2. A high volume of air intake leads to high duct pressure; if the pipe diameter is sufficient, consider using an inverter to adjust the air intake volume
1. In reality, only 4KPa is required. 2. The pressure in the furnace is controlled by the subsequent pressure, and is not affected by the pressure ahead. The pressure of the blower ahead is high; reduce the opening degree of the flow control valve to properly regulate the flow rate.
Currently, the blower operates at 8 kPa with a flow rate of 500 m3/h, while the pressure head of the exhaust fan is 2 kPa. It is functioning properly at present, but when the load on the furnace increases, the amount of air entering the furnace rises to 800 m3/h. What will be the pressure inside the furnace?
Did the poster only pay attention to the blower and not the exhaust fan? The principle is very simple: when the load on your blower increases, the exhaust fan must also increase its capacity in order to maintain a constant negative pressure in the furnace. . After loading, your fan handles an additional 300 cubic feet of air volume; if this volume cannot be expelled promptly by the exhaust fan, the pressure inside your furnace will increase. This is precisely the characteristic of a simple flow-stabilization process. . . Input – Output = Accumulation; if there is more input and less output, then accumulation naturally occurs. . . Conversely, if less enters and more exits, the accumulation becomes negative, and the furnace pressure will drop. .
Yes, I am indeed considering the airflow and pressure of the exhaust fan, as well as replacing it. But I don’t know how the furnace pressure changes when the inlet flow rate of the blower increases.
It’s not very clear how the pressure changes. By comparing the inflow and outflow flows, you can tell whether the pressure is high or low. Just explain how the pressure inside your furnace is controlled Connect pressure to the outlet flow in a cascade configuration, and then adjust the inlet flow.
The control of this phenomenon during operation should be based on the flow rate and pressure you require; regarding the operation of the exhaust fan, it is also necessary to coordinate with the blower. The key issue is that your high-pressure fan also has a high rated flow rate. This has nothing to do with the pipe diameter or the furnace diameter. What is required is how to use a part of it to meet production needs; focusing on that is sufficient. As for load changes, an increase in furnace pressure is another matter. If the furnace can handle the airflow volume you provide, then go ahead and increase it, as your fan is capable of delivering a greater airflow volume. So, what you need to do is figure out how to turn the large fans you have into smaller fans that meet the system’s requirements. As for the load regulation of the fan, it includes suction regulation, partial exhaust air regulation, and variable frequency regulation. As long as your device is operating within its designed parameters, you can adjust it freely.