Water Pump Asymmetric Clearance to Reduce Impeller Thrust
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Solution Overview
Problem
Conventional water pumps experience reduced performance and efficiency due to upward thrust generated by the impeller, leading to increased friction and reduced durability of the bearings supporting the rotor's rotation shaft.
Innovation Solution
The water pump design incorporates specific gaps and protrusions in the upper and lower casings to balance the upward and downward thrust forces, featuring a centrifugal impeller with distinct radial and axial gaps, a pressure chamber, and strategically positioned bulkheads to offset thrust, thereby reducing overall thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the impeller rotates to pressurize and discharge fluid, then the water pump achieves its pumping function, but an upward thrust is generated that causes the impeller and rotor to move axially upward
Solution Approach 1:
The patent introduces a downward thrust generation mechanism through the lower bulkhead and lower casing design. The lower bulkhead protrudes into the impeller accommodating space, creating a pressure differential that generates downward thrust to counterbalance the upward thrust from fluid pressure between the impeller and upper casing. This counterweight approach directly addresses the axial movement problem by applying an opposing force.
Solution Approach 2:
The patent employs asymmetric gap design where the gap between the impeller outer end and the upper bulkhead is deliberately made larger than the gap between the impeller outer end and the lower bulkhead. This asymmetric configuration creates different pressure distributions on the upper and lower sides of the impeller, resulting in a net downward thrust that counterbalances the upward thrust force.
2Force
If the impeller and rotor move axially upward due to upward thrust, then the thrust force is generated, but friction increases in the bearings supporting the rotation shaft
Solution Approach 1:
By generating downward thrust through the lower bulkhead structure, the patent creates a balancing force that reduces the net axial load on the bearings. This counterweight mechanism directly reduces the friction and wear in the bearings that support the rotation shaft, thereby improving reliability and durability.
3Force
If the gap between the impeller and upper bulkhead is made larger than the gap between the impeller and lower bulkhead, then downward thrust is generated to balance upward thrust, but the structural complexity increases
Solution Approach 1:
The patent integrates the thrust balance function into the existing casing structure by forming the upper and lower bulkheads as part of the upper and lower casings respectively. This merging of functions allows the thrust balance mechanism to be achieved without adding separate external components, thereby limiting the increase in structural complexity.
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 significantly reduces thrust, maintaining pressure and efficiency while enhancing the durability of the water pump by minimizing friction between the rotor's shaft and bearings.
Implementation Method 1
the fluid introduced into the inlet pipe 61 formed in the upper casing 60 by the rotation of the impeller 50 may be pressurized through the impeller 50 and then discharged through an outlet pipe 62 formed in the upper casing 60
Implementation Method 2
since the fluid pressure between the upper surface of the impeller 50 and the upper casing 60 is lower than that between the lower surface of the impeller 50 and the can 30, an upward thrust is generated that causes the impeller 50 and the rotor 40 to move axially upward
Data Source
AI summary
The present disclosure relates to a water pump in which an upper casing and a lower casing are coupled to each other and an impeller is rotatably accommodated therein, in which the upper casing has an upper bulkhead formed to protrude at a position between an impeller accommodating space and a discharge channel in a radial direction, the lower casing has a lower bulkhead formed to protrude at a position between the impeller accommodating space and the discharge channel in the radial direction, and a gap (TcA) between an upper side of an outer side end of the impeller and the upper bulkhead in the radial direction is formed greater than a gap (TcB) between a lower side of the outer side end of the impeller and the lower bulkhead in the radial direction, thereby reducing a thrust generated when the impeller rotates.