Pitot Pump Rotor Assembly Axial Thrust Reduction
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Solution Overview
Problem
Conventional centrifugal pumps of the pitot type experience elevated pressures at the axial center of the rotor assembly, leading to high axial thrust and reduced efficiency, which affects the bearing system and recirculation, particularly in concentric inlet-discharge arrangements.
Innovation Solution
The design incorporates a rotor assembly with primary and secondary channels that redirect fluid flow from the center to the peripheral annular portion of the fluid chamber, reducing pressure at the rotational axis by positioning the fluid inlet and pitot tube assembly to alleviate these pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional pitot tube pump configurations are used with concentric inlet-discharge arrangements, then the pump structure is simple and easy to manufacture, but elevated pressures at the axial center cause high axial thrust and reduced efficiency
Solution Approach 1:
The pump is divided into two distinct configurations: concentric arrangement for simple applications and co-axial non-concentric arrangement for applications requiring reduced axial thrust. This segmentation allows users to select the appropriate configuration based on their specific needs, resolving the contradiction between manufacturing simplicity and bearing system performance.
Solution Approach 2:
The invention introduces local quality changes by positioning the discharge outlet at a non-concentric location relative to the inlet in the co-axial configuration. This localized structural modification specifically addresses the pressure distribution issue at the axial center without fundamentally changing the overall pump design, thereby reducing axial thrust on bearings while maintaining manufacturing feasibility.
2Device complexity
If conventional pitot tube pump configurations are used, then the device complexity is low, but elevated pressures cause high recirculation and reduced pump efficiency
Solution Approach 1:
The invention employs asymmetry by positioning the discharge outlet in a non-concentric location relative to the inlet in the co-axial configuration. This asymmetric arrangement disrupts the symmetrical pressure distribution that causes recirculation in conventional designs, thereby improving pump efficiency while adding only minimal complexity to the overall device.
3Power
If elevated pressures are present at the axial center of the rotor assembly, then the pump can move fluid effectively, but the axial thrust adversely affects the bearing system
Solution Approach 1:
The co-axial non-concentric configuration acts as a counterbalancing design that offsets the axial thrust generated by pressure at the rotor center. By positioning the discharge outlet away from the concentric position, the design creates a counteracting force distribution that reduces the net axial thrust on bearings while preserving the pump's fluid moving capability.
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 configuration effectively reduces axial thrust on the bearings and improves pump operation and efficiency by mitigating the adverse effects of elevated pressures near the rotor assembly's centerline.
Implementation Method 1
as the rotor assembly rotates, the fluid is directed toward the interior peripheral surface of the rotor chamber as a result of centrifugal forces
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A rotor assembly for a centrifugal pump includes a rotor and a rotor cover, defining a fluid chamber therebetween, and having openings or channels that are provided in either the rotor cover or the rotor, or both, to direct fluid from the fluid chamber into the rotor or rotor cover of the rotor assembly to provide reduction of increased pressure that is experienced within the fluid chamber, especially at or near the center of the fluid chamber.