Centrifugal Pump Impeller Blade Angle Profile for Clogging Prevention
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Solution Overview
Problem
Conventional multi-blade centrifugal pump impellers experience cavitation and clogging issues due to high-speed areas leading to fiber accumulation and stagnation points on the pressure side, especially at part-load operation, which reduces efficiency and increases the risk of blockages.
Innovation Solution
The impeller design features a blade angle progression where the inlet angle is less than 0°, increasing to 0° in the first section, then to a maximum in the second section, and decreasing in the third section, with a constant angle in the fourth section, creating a strong curvature that shifts the stagnation point to the suction side, reducing fiber adhesion and promoting detachment, thus preventing clogging and cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller operates at high specific speeds, then productivity is improved, but the stagnation point shifts to the discharge side causing fiber accumulation and clogging
Solution Approach 1:
The patent changes the geometric parameters of the blade profile, specifically setting the blade entry angle to less than 0° and creating a pronounced curvature with the stagnation point on the suction side. This parameter modification shifts the flow characteristics to prevent fiber accumulation even at high specific speeds, resolving the contradiction between productivity and clogging resistance
Solution Approach 2:
The patent employs a blade profile with pronounced curvature where the stagnation point is positioned on the suction side rather than the discharge side. This curvature design creates favorable flow conditions that prevent fiber accumulation and maintain reliability at high operating speeds
2Weight of moving object
If the blade leading edge has a small radius of curvature, then the impeller becomes slim and lightweight, but high-velocity zones cause cavitation
Solution Approach 1:
The patent modifies the blade angle parameters, specifically setting the entry angle to less than 0° and defining a specific curvature profile. These parameter changes allow the use of small leading edge radii without causing cavitation, as the altered angle profile redistributes the velocity distribution to prevent vapor bubble formation
3Object-affected harmful factors
If the blade angle at inlet is increased to reduce cavitation, then cavitation is prevented, but fiber accumulation occurs on the pressure side
Solution Approach 1:
The patent uses a blade profile with pronounced curvature where the stagnation point is positioned on the suction side. This curvature configuration achieves both cavitation prevention and fiber accumulation prevention by creating favorable pressure and velocity distributions along the blade surface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures even load distribution, reduces fiber adhesion, and maintains high efficiency by keeping the separation area small, preventing impeller clogging and cavitation damage, even at high specific speeds, allowing for a slim and lightweight impeller with small blade leading edge radii.
Implementation Method 1
the stagnation point of the flow shifts from the pressure side to the region of maximum curvature of the leading edge, or even to the suction side
Implementation Method 2
If, due to the high flow velocity, the static pressure drops below the vapor pressure, vapor bubbles form, leading to cavitation damage
Implementation Method 3
When air flows around the leading edges of the blades, there is a high-velocity zone. For impellers with a small radius of curvature at the leading edge, the velocities in this zone are particularly high. If, due to the high flow velocity, the static pressure drops below the vapor pressure
Implementation Method 4
Impeller for centrifugal pumps with at least two blades for conveying media containing solids
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to an impeller of a centrifugal pump, comprising at least two blades (4) for conveying media containing solids. According to the invention, the blade leading angle (ß1) is smaller than 0°. The blade angle (ß) increases in a first section (9) until a value of 0° is reached. In a second section (10), another increase occurs until a maximum value is reached. In a third section (11), the blade angle (ß) decreases again.