Curved Vane Impeller Reduces Shear in Centrifugal Pumps
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Solution Overview
Problem
Conventional centrifugal pumps generate high shearing forces that can damage shear-sensitive liquids and solids, limiting their application and efficiency, especially in food processing, pharmaceutical processing, and clay slurry applications, where low shear forces are required to maintain fluid integrity.
Innovation Solution
A centrifugal pump design featuring an impeller with radially outward vanes that sweep an arc around the impeller axis, reducing shear forces by providing a smooth path for fluid flow and minimizing recirculation, combined with a casing that facilitates efficient fluid transfer from kinetic to potential energy, reducing mechanical damage and power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the impeller is rotated at accelerated speeds to produce high head output, then the head generation capability is improved, but shearing forces applied to the fluid increase significantly
Solution Approach 1:
The impeller vanes are designed with a specific curvature and arc sweep pattern that follows the fluid flow path more naturally. The vanes sweep an arc around the impeller axis rather than extending radially straight outward, creating a smoother flow path that reduces turbulence and shearing forces while maintaining centrifugal pumping action for head generation
Solution Approach 2:
The invention changes the geometric parameters of the impeller vanes, specifically the arc sweep angle and vane orientation, to optimize the balance between head generation and shear force reduction. This allows the impeller to operate at higher speeds for improved head output without proportionally increasing shearing forces on the fluid
2Object-affected harmful factors
If the impeller is operated at low pump speed to avoid shearing forces, then the shearing forces are reduced, but the head output decreases
Solution Approach 1:
The curved vane design with arc sweep creates a more efficient fluid path that reduces energy losses and improves pumping effectiveness, allowing the impeller to achieve adequate head output at lower rotational speeds, thereby reducing shearing forces on shear-sensitive fluids
3Object-affected harmful factors
If low shear centrifugal pump designs are used to minimize shearing forces, then the shearing forces are reduced, but the pump efficiency decreases and internal recirculation increases
Solution Approach 1:
The specific arc sweep geometry of the vanes is designed to minimize flow separation and recirculation zones while maintaining low shear characteristics. The curved path guides fluid smoothly through the impeller, reducing internal recirculation and improving overall pump efficiency without compromising the low shear force advantage
Solution Approach 2:
Optimization of vane geometry parameters including arc sweep angle, vane spacing, and surface curvature creates a flow pattern that reduces internal recirculation while maintaining low shearing forces, thereby improving pump efficiency in shear-sensitive applications
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
The design effectively pumps shear-sensitive liquids and solids with high efficiency and low product damage, as evidenced by stable acid degree values in dairy processing, and can be applied to various sensitive fluid applications, enhancing pump performance and reducing mechanical agitation.
Implementation Method 1
the rotation of the impeller typically forces fluid to flow radially outward toward an outlet of the cavity
Implementation Method 2
The vanes of the impeller are formed to cause the fluid moving over the vanes to apply a hydrodynamic force to the vane that opposes the force applied to the vane by fluid as the vane urges fluid through the pump
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An improved impeller (10) and a casing (37) for a centrifugal pump are disclosed. The impeller (10) comprises vanes (14a,b) which sweep an arc around an impeller axis (18) to provide a smooth path past the impeller (10) and through the pump. The casing (37) is constructed to allow maximum flow rate at the eye of the impeller (10) then shrink the flow channel to reduce internal recirculation promote efficiency, further limiting the effect of damaging forces. The impeller (10) is suited for use in pumps in which a high head is required and in which only low shear forces must be applied to the fluid moving through the pump.