In pneumatic conveying systems, the selection of Roots blowers is a critical step that directly affects the conveying efficiency and stability of the system. The following are the main factors to consider when selecting Roots blowers for pneumatic conveying:
1、 Traffic demand
1. Determining the flow range: The flow demand of the pneumatic conveying system is the basis for selection. It is necessary to calculate the required volumetric or mass flow rate of the system based on actual operating conditions, usually in units of standard cubic meters per minute (m3/min) or kilograms per hour (kg/h).
2. Consider margin: In order to cope with possible flow fluctuations and air leakage losses, a blower slightly larger than the required flow rate of the system should be selected during selection, with a margin coefficient generally ranging from 1.1 to 1.25 times.
2、 Pressure demand
1. Determine the pressure rise requirement: The pressure rise of the Roots blower should be balanced with the required pressure drop of the system. When selecting, it is necessary to choose a blower with sufficient boosting capacity based on the calculation results of system pressure drop. Similarly, for the sake of conservatism, a margin of 1.05 to 1.15 times the system pressure drop should be left when determining the boost of the blower.
2. Consider the vertical height and the number of curves: the higher the vertical height, the more curves there are, requiring higher pressure to work. Therefore, when selecting, it is necessary to fully consider the impact of the vertical height of the conveyor and the number of bends on the pressure demand.
3、 Medium characteristics
1. Medium type: Roots blowers are commonly used for transporting gases. When selecting, the type of fan should be determined based on the diameter of the material. Dilute phase materials are suitable for using Roots blowers as gas sources.
2. Corrosivity of media: For media with corrosiveness, it is necessary to choose blower materials and sealing types with good corrosion resistance. For example, when transporting oxygen and chlorine gas, aluminum alloy materials should not be used for the parts in contact with them.
4、 Model selection
1. Structural types: Roots blowers come in various structural types, such as vertical and horizontal. When selecting, it is necessary to choose the appropriate structural type based on the installation space and the convenience of operation and maintenance.
2. Performance specifications: After determining the flow and pressure requirements, other performance specifications of the blower, such as speed, power, etc., also need to be considered. These factors will directly affect the operating efficiency and energy consumption of the blower.
5、 Economy and applicability
1. Cost effectiveness: Under the premise of meeting performance requirements, cost-effective blower models should be selected. This includes considering the purchase cost, operating cost, and maintenance cost of the blower.
2. Reliability: The reliability of the blower is an important factor that cannot be ignored when selecting. Products with reliable quality and stable performance should be selected to ensure the long-term stable operation of the system.
In summary, the selection of Roots blowers for pneumatic conveying is a comprehensive process that requires consideration of multiple factors such as flow rate, pressure, medium characteristics, model selection, as well as economy and applicability. Through scientific and rational selection, the stability and operation of the pneumatic conveying system can be ensured.
