Floating Rotatory Drum Sealing in Hydraulic Axial Piston Pumps

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Solution Overview

Problem

Hydraulic axial piston pumps with energy recovery in seawater reverse osmosis desalination systems face issues with sealed closure between the rotatory drum and fluid-distributing plates due to lateral tilt and misalignment, leading to liquid leakage and excessive wear, caused by the axial and opposing movement of pistons.

Innovation Solution

The implementation of rotating strips with clearance for axial and longitudinal movement, coupled with sealing elements and springs, ensures a sealed closure and balances the drum against fluid-distributing plates, allowing for tilt and misalignment while maintaining sealing, and utilizing suitably aligned and sized openings and conduits to neutralize axial forces from primary and secondary liquids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tight sealing between the rotatory drum and fluid-distributing plates is implemented, then liquid leakage is prevented, but the drum cannot rotate due to lack of clearance

Engineering Contradiction:
Improvesealing effectivenessVSAvoiddrum rotation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A flexible sealing strip is introduced as an intermediary element between the rotatory drum and the fluid-distributing plates. This strip rotates with the drum while maintaining continuous contact with the plates, providing effective sealing without preventing drum rotation. The flexible nature of the strip allows it to accommodate the clearance needed for rotation while preventing liquid leakage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the drum is fixed rigidly to prevent lateral tilt, then alignment is improved, but excessive wear occurs due to inability to accommodate piston movement

Engineering Contradiction:
Improvedrum alignmentVSAvoidservice life
Core Design Contradiction:
Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The drum is designed to float rather than be rigidly fixed, allowing it to dynamically adjust its position and accommodate lateral tilt caused by piston movement. This dynamic capability enables the drum to self-align during operation, maintaining proper alignment while preventing excessive wear through controlled movement.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If clearance is increased to allow drum rotation, then drum rotation is enabled, but liquid leakage increases

Engineering Contradiction:
Improvedrum rotationVSAvoidliquid leakage
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

A flexible sealing strip acts as a thin film that rotates with the drum, filling the clearance gap between the drum and fluid-distributing plates. This flexible element maintains sealing effectiveness while allowing the necessary clearance for smooth drum rotation, preventing liquid leakage that would occur with larger rigid clearances.

Inventive Principle:
Principle #30Flexible shells and thin films

4Stability of the object's composition

If the drum is constrained to prevent lateral tilt, then alignment is maintained, but friction and wear increase

Engineering Contradiction:
Improvedrum alignmentVSAvoidfriction and wear
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The floating drum design allows the drum to dynamically adjust its position and accommodate lateral tilt caused by piston movement. This dynamic capability enables the drum to self-align during operation, maintaining proper alignment while preventing excessive wear through controlled movement and reducing friction between the drum and fluid-distributing plates.

Inventive Principle:
Principle #15Dynamics

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 prevents liquid leakage and maintains drum balance, reducing wear and ensuring prolonged operation by maintaining a sealed closure and balancing axial forces, thus enhancing the operational efficiency and longevity of the pump.

Implementation Method 1

springs oriented in the axial direction and suitable to press said strips against the respective distributing plates

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the pressures of the primary liquid and secondary liquid also act on the drum, causing the drum to become imbalanced in the axial direction

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP3070329B1Hydraulic axial piston pump having a floating rotatory drum
Publication Date: 2019.02.27 ECO SISTEMS WATERMAKERS
  • EP3070329B1 patent drawingFigure 1
  • EP3070329B1 patent drawingFigure 2

AI summary

The invention relates to a pump comprising: a housing (1); a drum (2) having cylinders in which pistons (3) are mounted, which pistons are supported by supporting shoes (32) on a fixed inclined plate (4); and first and second fluid-distributing plates (5a, 5b) having openings (51, 52) for establishing in an alternating manner the connection between first mouths (23) of the cylinders (22) and a first inlet (11) and first outlet (12) of primary liquid, and between second mouths (24) and a second inlet (13) and second outlet (14) of the secondary liquid. The pump comprises first and second strips (6a, 6b) arranged between the drum (2) and the distributing plates (5a, 5b), said strips being movable in a longitudinal direction and allowing the drum to tilt to a certain extent, forming a sealed closure between the ends of the drum (2) and the distributing plates (5a, 5b).