Flexible Annular Lip Seal for Centrifugal Pump Recirculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Centrifugal pumps face inefficiencies due to liquid recirculation and solid particle interference, leading to yield losses and potential seizure, as existing sealing solutions fail to reliably prevent fluid return and accommodate abrasive particles.
Innovation Solution
A discoid seal ring with a flexible, rubber annular lip that transitions between a rest and active configuration, allowing passage of solid particles when stopped and achieving a tight seal during operation, minimizing recirculation and friction through a dynamic liquid film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid seal ring is used to prevent liquid recirculation, then sealing efficiency is improved, but the risk of seizure due to solid particle blockage increases
Solution Approach 1:
The seal ring incorporates a flexible annular lip that can dynamically change its position and configuration. During pump operation, the lip assumes a first configuration that provides effective sealing. When the pump is stopped, the lip transitions to a second configuration that creates clearance for solid particle passage, preventing blockage and seizure.
Solution Approach 2:
The seal ring utilizes elastic deformation to change the gap parameter between the lip and the impeller surface. This dynamic parameter change allows the system to adapt between sealing mode (small gap) and particle passage mode (larger gap), resolving the contradiction between sealing efficiency and particle blockage prevention.
2Loss of energy
If a tight seal is maintained during operation, then liquid recirculation is reduced, but friction and energy loss increase
Solution Approach 1:
The seal ring operates in periodic cycles, transitioning between a tight sealing configuration during pump operation and a more open configuration during idle periods. This periodic adjustment optimizes the balance between preventing liquid recirculation during operation and minimizing friction when the pump is not running.
3Reliability
If the seal ring is designed for high sealing pressure, then recirculation prevention is improved, but the complexity of the sealing mechanism increases
Solution Approach 1:
The seal ring utilizes the existing hydraulic pressure differential across the impeller to automatically position the flexible lip in the appropriate configuration. The system self-regulates without external control mechanisms, using the pump's operating pressure to maintain optimal sealing contact during operation and allowing the lip to relax during idle periods.
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
Ensures reliable, high-yield operation by preventing seizure and reducing fluid recirculation, accommodating abrasive particles, and minimizing friction, suitable for various motor types, including those with reduced acceleration performance.
Implementation Method 1
a flexible, rubber annular lip (24) which is elastically mobile between a rest configuration (24a), when the pump is stopped, and an active configuration (24b), when the pump is operating
Implementation Method 2
the crossing fluid is thus subjected to a substantially centrifugal motion which increases the fluid dynamic energy thereof
Implementation Method 3
the diffuser member generally comprises a plurality of sectors suitable to convey the return of the fluid from the peripheral zone in proximity of the case to the central zone in proximity of the inlet section
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The centrifugal pump comprises at least one impeller member (4) suitable to be driven in rotation for transporting a fluid, sealing means (20) fixed at the body of the pump and cooperating with a feed portion (8) of the impeller member (4). The sealing means (20) comprise at least one flexible portion (23) shaping an annular lip (24), suitable to be elastically driven between a rest configuration (24a) at which said annular lip (24) is at a distance by a meatus (26) of determined width from an opposite external surface (15) of said feed portion (8) and a tight active configuration (24b) at which said annular lip (24) is stressed in abutment against said external surface (15) upon the thrust of the transported fluid.