Floating Bushing Slurry Seal Assembly for Low-Flow Leakage Control

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Solution Overview

Problem

Existing slurry pump sealing assemblies face challenges with heat-induced and vibration-induced damage, and they require unsustainable mass flow rates to prevent slurry from contacting primary sealing elements, leading to inadequate leakage prevention and reduced seal life.

Innovation Solution

A floating bushing seal assembly with rotatable slots that enhance fluid flow velocity and dispersal to physically separate and redirect slurry away from the sealing interface, reducing the gap size and mass flow rate required, thus preventing slurry contact with the seal rings and enhancing seal performance and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a large radial gap is provided between the wear layer and sleeve cover to accommodate thermal expansion and vibrations, then the seal assembly can withstand thermal and vibration conditions, but the mass flow rate of fluid required to resist slurry counter flow increases significantly

Engineering Contradiction:
Improvethermal and vibration accommodationVSAvoidmass flow rate of fluid
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The bushing seal assembly is divided into a fixed portion (bushing arm attached to flange) and a floating portion (wear layer that can move independently). This segmentation allows the wear layer to accommodate thermal expansion and vibrations through relative movement while maintaining a smaller effective gap, thereby reducing the mass flow rate requirement compared to a completely fixed bushing design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wear layer is designed to float and move dynamically relative to the sleeve cover, transitioning from a static fixed gap design to a dynamic adjustable gap design. This dynamic capability allows the system to maintain optimal sealing clearance under varying thermal and vibrational conditions without requiring a consistently large gap, thus reducing fluid consumption.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If a fixed bushing seal assembly is used with a large gap, then thermal and vibration conditions are accommodated, but contact between the bushing assembly and sleeve is inevitable under certain conditions, increasing likelihood of damage

Engineering Contradiction:
Improvethermal and vibration accommodationVSAvoiddamage resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The floating wear layer can dynamically adjust its position and absorb thermal expansion and vibration-induced movements, preventing rigid contact between the bushing assembly and sleeve that would occur in a fixed design. This dynamic compliance significantly reduces the likelihood of damage under thermal and vibrational stress.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The floating design provides a cushioning effect by allowing the wear layer to move and absorb shocks before they can be transmitted to the sleeve or bushing arm, preventing damage before it occurs rather than relying on post-failure repairs.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a large mass flow rate is used to prevent slurry from crossing the gap, then leakage prevention is improved, but the fluid quantity required becomes unsustainable in remote or arid locations

Engineering Contradiction:
Improveleakage preventionVSAvoidfluid quantity required
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

By segmenting the seal assembly into fixed and floating portions, the system achieves effective sealing with a smaller gap, which directly reduces the mass flow rate requirement. This segmentation enables sustainable operation in remote locations where large fluid quantities would be impractical to supply.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the operational parameters by reducing the gap size through the floating bushing mechanism, which exponentially reduces the mass flow rate requirement compared to a large fixed gap design, making the system viable for remote applications with limited fluid supply capacity.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If a smaller gap is used to reduce mass flow rate, then fluid consumption is reduced, but the gap cannot accommodate thermal expansion and vibrations

Engineering Contradiction:
Improvemass flow rate of fluidVSAvoidthermal and vibration accommodation
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The segmentation of the bushing into fixed and floating portions resolves this contradiction by allowing the floating wear layer to maintain a small gap for reduced fluid consumption while simultaneously accommodating thermal expansion and vibrations through its ability to move independently from the fixed bushing arm.

Inventive Principle:
Principle #1Segmentation

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 solution effectively reduces the mass flow rate and total fluid quantity needed, improves resistance to upstream slurry flow, and increases seal life by avoiding damage to sealing components, making it adaptable to conventional pump designs.

Implementation Method 1

The velocity and pressure of the fluid traversing the gap must be sufficient to prevent a slurry, originating in the slurry side, from reaching the seal rings by crossing the gap in the direction opposite to that of the fluid flow

Methodology Applied
Scientific EffectFluid flow velocity and pressure: Pressure Gradient

Implementation Method 2

A floating bushing seal assembly with rotatable slots that enhance fluid flow velocity and dispersal to physically separate and redirect slurry away from the sealing interface

Methodology Applied
Scientific EffectRotational motion: Centrifugal Force

Data Source

PatentEP3337982B1Slurry seal assembly
Publication Date: 2022.03.02 STEIN SEAL CO
  • EP3337982B1 patent drawingFigure 1
  • EP3337982B1 patent drawingFigure 2~3
  • EP3337982B1 patent drawingFigure 4

AI summary

A slurry seal assembly (20) for use about a rotatable shaft (21) between a process side (54) and an atmosphere side (55) is presented. The slurry seal assembly (20) includes a sleeve (22), a rotatable seal ring (23), a stationary seal ring (24), a floating bushing seal assembly (50), and a plurality of slots (52). The sleeve (22) is disposed about and rotatable with the shaft (21). The rotatable seal ring (23) contacts and is rotatable with the sleeve (22). The stationary seal ring (24) is arranged to form a sealing interface (25) with the rotatable seal ring (23). The floating bushing seal assembly (50) is disposed about the sleeve (22) so that an inner annular surface (66) along the floating bushing seal assembly (50) is separated from an outer annular surface (67) along the sleeve (22) by a gap (65). The slots (52) are disposed along the sleeve (22) within the process side (54) adjacent to the floating bushing seal assembly (50). The slurry seal assembly (20) is applicable to devices whereby a fluid is movable between an inlet and an outlet.