Submersible Centrifugal Pump with Dynamic Impeller Seat
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Solution Overview
Problem
Submersible centrifugal pumps face challenges in handling liquids or slurries with hard solid matter that cannot be cut or screened, as existing solutions either reduce solid size or provide permanent gaps that can lead to obstruction or wedging of solids between components.
Innovation Solution
The pump assembly features an impeller seat that is journalled for limited rotational and axial movements, allowing for ejection of large solids by creating an axial gap between the impeller and the seat, with guide means and bias mechanisms to ensure smooth operation and return to normal position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent gaps are provided between rotary and stationary components to allow solids passage, then solids can pass through the pump, but pump capacity is reduced and solids may still wedge between components
Solution Approach 1:
The impeller seat is made dynamically adjustable rather than fixed, allowing it to move axially between a normal operating position (maintaining pump capacity) and an ejection position (creating gap for solids ejection). This dynamic adjustment resolves the contradiction by providing solids passage capability only when needed, without permanently reducing pump capacity.
Solution Approach 2:
The axial position of the impeller seat is changed as a parameter to control the gap size between impeller and seat. By varying this parameter between two states (normal position with minimal gap for high capacity, and ejection position with larger gap for solids passage), the system achieves both high pump capacity and reliable solids ejection capability.
2Reliability
If impeller is displaced axially to eject large solids, then solids ejection is achieved, but pump operation is interrupted
Solution Approach 1:
The impeller seat performs periodic axial movements between normal and ejection positions. Instead of remaining displaced for extended periods, the seat quickly moves to the ejection position, ejects solids, and returns to the normal position, minimizing operational interruption while maintaining reliable solids ejection function.
Solution Approach 2:
The transition of the impeller seat between positions is executed rapidly rather than gradually. The seat quickly skips from the normal operating position to the ejection position and back, minimizing the time the pump operates in a non-optimal state and reducing overall operational interruption.
3Reliability
If guide means are added to control impeller seat movement, then operational reliability is improved, but device complexity increases
Solution Approach 1:
The guide means is segmented into multiple simple guide elements distributed around the impeller seat perimeter, rather than using a single complex guiding mechanism. This segmentation provides reliable controlled movement through distributed guidance while keeping each individual guide element simple in structure.
Solution Approach 2:
The guide means acts as an intermediary mechanism between the impeller seat and the pump housing, providing controlled movement without requiring direct complex mechanical linkages. This intermediary guidance system simplifies the overall structure while ensuring reliable controlled movement of the impeller seat.
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 enhances the ejection function of submersible centrifugal pumps, allowing for efficient passage of large solids without compromising pump capacity or risk of obstruction, improving operational reliability.
Implementation Method 1
accelerating the liquid and solid matter through centrifugal action via a radial discharge on the pressure side of the pump
Implementation Method 2
a spring element (15) arranged to apply, in an axial direction, a force which effects a displacement by which the impeller seat is returned to its normal operational position
Data Source
AI summary
The present invention relates to a submersible centrifugal pump assembly comprising an impeller suspended in the end of a drive shaft, and driven in rotation relative to an impeller seat which is stationary in normal operation and which defines an axial intake for liquid to be transported by the impeller in rotation. The pump assembly is characterized in that the impeller seat is journalled in a pump housing for limited rotational movements in opposite directions of rotation relative to the pump housing, and in rotation controlled in guide means for limited linear displacements in opposite axial directions relative to the impeller.