The application of blowers in pneumatic conveying systems

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A hybrid pneumatic conveyor consists of a suction section and a compression section, which are the basic components of pneumatic conveying. Compression feeders can be classified according to their working principle as follows: 1. Jet feeders: Suitable for pneumatic conveying systems with low pressure and short distances； 2. Impeller feeder: Suitable for pneumatic conveyors operating at medium and low pressures, used for transporting powdered and small lumpy materials ； 3. Screw feeder: The screw feeder is used in pressure pneumatic conveyors with a pressure of 2.5–3 atmospheres for transporting powdered materials ； 4. Positive-displacement feeder: Positive-displacement feeders are suitable for high-pressure pneumatic conveyors used to transport powdered or fine-grained materials ； Conveyor pipe: 1. Generally, steel pipes with a diameter of 50 mm to 300 mm are used, and their inner diameter is determined based on the air flow rate and the desired air flow velocity ； 2. The wall thickness of the conveyor pipe depends on the physical properties of the material being transported and the conveying pressure applied ； 3. The biggest problem with the feed pipe is bend wear ； Material separator: 1. A process for separating material particles by appropriately reducing the airflow velocity, changing the direction of the airflow, or utilizing centrifugal force ； 2. The most commonly used basic types at present are positive-displacement separators and centrifugal separators. Working principle of the positive-displacement separator: A mixture of air and material enters a container with a sudden increase in volume through a feed pipe, which reduces the speed of the air flow to well below the suspension velocity; as a result, the material particles lose the support of the air flow and sink to the bottom of the container, where they are discharged by a discharge device ； Working principle of the centrifugal separator: As the mixture enters the separator, it moves in a rotational downward motion along its interior. Upon reaching the conical section, the rotational radius decreases gradually, which causes the rotational speed to increase. As a result, the material particles in the airflow are subjected to greater centrifugal force, causing them to be thrown against the walls of the separator and to fall along those walls, thereby achieving separation ； Air dust collector: The air from which the material is removed often still contains many fine particles of material and dust. Centrifugal dust collectors and bag filters are commonly used in pneumatic conveyors ； Dischargers, ash dischargers: The most common design type is the impeller-type discharger (for ash) ； Blower: A blower generates an air flow with a certain pressure difference, which is used to overcome the pressure losses caused in various parts of the pneumatic conveying system. Commonly used blowers include centrifugal, rotary, and piston types. Rotary vane blowers are the most widely used type of blower. Centrifugal blower: composed of a volute and an impeller that rotates within it ； At smaller sizes, it can deliver a high air volume; it is lightweight and efficient, the air volume can be easily adjusted, and it can operate in dusty air ； Rotary blower: Inside its casing, there are two waist-shaped rotors with a 90° phase difference and opposite rotation directions. There is a gap of approximately 0.3 to 0.5 millimeters between the rotors and between the rotors and the casing, to ensure that the rotors can rotate properly without causing air leakage ； Roots blower: Compact design, stable operation, high operating noise; requires clean air ；