In the segmented field of pump equipment, the impeller, as a core working component, its structural design directly affects the pump's operating efficiency, application range, and operational stability. As two common types of centrifugal pumps, open impeller pumps and closed impeller pumps exhibit distinctly different characteristics in practical applications due to differences in impeller structure.
Their key feature lies in the open structure of the impeller. The impeller consists only of a hub and blades, with no cover plates shielding either side of the blades; the edges of the blades are directly exposed inside the pump chamber. This structural design results in a relatively large gap between the impeller and the pump chamber, making it easy for the liquid to come into contact with the inner wall of the pump chamber during flow.
They adopt a fully enclosed structure. In addition to the hub and blades, the impeller is equipped with two front and rear cover plates. The blades are completely enclosed between these two cover plates and only connect to the outside through the inlet at the center of the cover plates. The presence of the cover plates not only fixes the position of the blades but also forms a closed liquid flow channel, reducing direct contact between the liquid and other components of the pump chamber.
Their operation relies on the direct pushing of the liquid by the blades. When the motor drives the impeller to rotate, the high-speed rotating blades generate centrifugal force, pushing the liquid entering the pump chamber from the root of the blades to the edges, and then discharging it through the flow channel of the pump casing. Since there are no cover plates to shield the blades, some liquid may spread to both sides of the impeller under the action of centrifugal force, leading to a certain degree of energy loss.
The liquid flow in closed impeller pumps is more directional. After the liquid enters through the central inlet of the impeller, it is confined in the closed flow channel formed by the front and rear cover plates and the blades. As the impeller rotates, the liquid moves centrifugally along the direction of the blades in the flow channel, and finally is thrown out from the edge of the impeller into the flow channel of the pump casing. The closed flow channel reduces the diffusion loss of the liquid, concentrates energy transfer, and improves the efficiency of converting kinetic energy into liquid pressure energy.
Because the impeller has no cover plates to block, the flow channel is not easily clogged by impurities, making it more suitable for transporting media containing solid particles, fibers, or high-viscosity media. For example, in scenarios such as sewage treatment, construction drainage, and slurry transportation, impurities that may exist in the medium are not easily stuck between the impeller and the cover plates, reducing the probability of pump failure. At the same time, its simple structure allows for easy disassembly and cleaning, with relatively low maintenance costs.
They are more suitable for transporting clean, impurity-free liquids. In industries such as chemical engineering, pharmaceuticals, and food processing that have high requirements for medium purity, the closed flow channel can avoid secondary contact between the liquid
and the pump chamber components, reducing the risk of medium contamination. In addition, due to their high energy transfer efficiency, closed impeller pumps are also often used in scenarios that require strict flow stability and pressure output, such as precision equipment cooling and liquid circulation systems.
In terms of operating efficiency, closed impeller pumps have higher overall efficiency than open impeller pumps because the closed flow channel reduces energy loss. This energy-saving advantage is more obvious especially in long-term continuous operation scenarios. On the other hand, open impeller pumps have relatively low efficiency due to liquid diffusion loss, making them more suitable for intermittent operation or scenarios with low efficiency requirements.
In terms of stability, the blades of closed impeller pumps are fixed by the cover plates, resulting in less vibration during rotation, lower operating noise, and a longer service life. For open impeller pumps, since the blades have no fixed structure, the blades are prone to deformation due to uneven force after long-term operation, which may lead to increased vibration and require more frequent inspection and maintenance.
In terms of maintenance costs, open impeller pumps have a simple structure, with low difficulty in component replacement and more convenient daily maintenance; closed impeller pumps have a complex structure. If cover plate damage or blade failure occurs, the disassembly and maintenance processes are more cumbersome, and the maintenance costs are relatively higher. When selecting a pump, a comprehensive judgment should be made based on the characteristics of the transported medium, the requirements of the operating scenario, and the maintenance cost budget: when transporting media containing impurities or high-viscosity media and pursuing convenient maintenance, open impeller pumps are a better choice; when transporting clean liquids and focusing on efficiency and stability, closed impeller pumps are more in line with the requirements. Mastering the core differences between the two types of pumps is essential to achieve the rational application of pump equipment and improve the overall efficiency of industrial production.
As a professional pump company, TEFFIKO can provide open and closed impeller pumps that meet the above characteristics, and can also provide customized selection solutions according to your specific working conditions to ensure that the equipment is accurately matched to the production needs. Whether you need an open impeller pump with strong impurity resistance or a closed impeller pump that focuses on high efficiency and stability, TEFFIKO provides high-quality product quality and comprehensive after-sales support to safeguard your production operations.
