Multi-Stage Pump Elastic Jacket for Sealing Stability

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Solution Overview

Problem

Multi-stage pumps experience tightness issues due to dilation of the external jacket under pressure and temperature changes, leading to reduced contact with gaskets and progressive loss of tightness over time.

Innovation Solution

The pump design incorporates axially elastic external jacket portions and tie rods to maintain constant compression force on gaskets, enhancing their adherence and stability by using annular gaskets in trapezoidal seats and adjusting the axial tightening force, while improving mechanical rigidity through annular grooves and laminate elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the external jacket is made rigid to maintain structural stability, then mechanical strength is improved, but tightness deteriorates due to dilation under pressure and temperature changes

Engineering Contradiction:
Improvemechanical strengthVSAvoidtightness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The external jacket is divided into rigid portions and elastic portions. The rigid portions maintain structural strength, while the elastic portions accommodate thermal and pressure-induced dilation, preventing gasket loss of tightness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the external jacket are assigned different mechanical properties: rigid portions for structural integrity and elastic portions for compliance with thermal/pressure expansion, optimizing both strength and tightness locally.

Inventive Principle:
Principle #3Local quality

2Reliability

If the gasket compression force is increased to improve tightness, then sealing reliability is improved, but the mechanical coupling rigidity deteriorates

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmechanical coupling rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The gasket compression force is made dynamic through the elastic portions that automatically adjust to thermal and pressure changes, maintaining optimal sealing force without requiring excessive mechanical coupling rigidity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The compression force parameters of the gaskets are dynamically adjusted by the elastic portions responding to temperature and pressure variations, maintaining effective sealing without compromising mechanical coupling.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the external jacket is made elastic to accommodate thermal and pressure dilation, then tightness is improved, but mechanical rigidity deteriorates

Engineering Contradiction:
ImprovetightnessVSAvoidmechanical rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The external jacket is segmented into rigid and elastic portions, each serving its specific function: rigid portions provide structural strength, while elastic portions accommodate thermal and pressure dilation to maintain tightness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different local regions of the external jacket have different mechanical properties tailored to their specific functional requirements, optimizing both rigidity where needed and elasticity where compliance is necessary.

Inventive Principle:
Principle #3Local quality

4Reliability

If the gasket contact pressure is increased to maintain tightness under dilation, then sealing performance is improved, but the compression force stability deteriorates

Engineering Contradiction:
Improvesealing performanceVSAvoidcompression force stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The elastic portions provide a feedback mechanism that automatically adjusts to thermal and pressure changes, maintaining stable and optimal gasket compression force throughout operation without external intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The compression force parameters are dynamically stabilized through the elastic portions' response to changing operating conditions, maintaining consistent sealing performance across varying temperatures and pressures.

Inventive Principle:
Principle #35Parameter changes

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 solution maintains constant gasket compression and improves tightness and mechanical stability over time, ensuring reliable sealing without costly design modifications, using existing gaskets and materials.

Implementation Method 1

a plurality of shaped annular portions (28) suited to make the external jacket (2) elastically yielding along the direction defined by the longitudinal axis (Y)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2366905B1Improved tight multi-stage pump
Publication Date: 2014.12.24 CALPEDA
  • EP2366905B1 patent drawingFigure 1
  • EP2366905B1 patent drawingFigure 2
  • EP2366905B1 patent drawingFigure 3~6

AI summary

The invention is a multi-stage pump (1) comprising an external jacket (2) with a suction port (3) and a delivery port (4), provided at one end with a casing cover (5) and at the opposite end with a lantern bracket (6) supporting an electric motor (7) associated with rotary pumping members (8). The casing cover (5) and the lantern bracket (6) are coupled to the ends of the external jacket (2) through fixing means with the interposition of annular gaskets (17). Each gasket is housed in an annular seat (18) defined by a shaped annular area (19) present in the casing cover (5) and the lantern bracket (6) and by a counter-shaped annular area (20) present in the corresponding end of the external jacket (2), opposing each other. The counter-shaped annular area (20) comprises an annular counteracting surface (20a), inclined with respect to the longitudinal axis (Y) defined by the external jacket (2), suited to compress the annular gasket (17) when the casing cover (5) and the lantern bracket (6) are coupled to the external jacket (2) through the tie rods. The external jacket (2) is provided with a plurality of shaped annular portions (28) suited to make the external jacket (2) elastically yielding along the direction defined by its longitudinal axis (Y) and the fixing means comprise a plurality of tie rods (12) each one of which is provided with a first end (12a) constrained to the casing cover (5) and a second end (12b) constrained to the lantern bracket (6).