Rocking Piston Compressor Sealing via Segment Design

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Solution Overview

Problem

Current connecting rod compressors face issues with increased wear on piston seals and cylinder walls due to transverse forces, and the joint between the connecting rod and piston contributes to oscillating mass and impaired concentricity, leading to higher loads on crankshaft bearings and reduced service life.

Innovation Solution

A connecting rod compressor design with a piston divided along its longitudinal axis and a spring-elastic layer between the parts, where the piston is shaped like a cylinder segment to maximize contact with the cylinder wall, and a compression chamber with intake and exhaust ports in a plane perpendicular to the crankshaft rotation, ensuring a large contact surface for sealing and reduced wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a connecting rod piston with articulated joint is used, then the piston can be connected to the crankshaft, but the joint increases oscillating mass and impairs concentricity, leading to higher loads on crankshaft bearings

Engineering Contradiction:
Improvejoint structureVSAvoidoscillating mass
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The patent merges the connecting rod and piston into a single rigid connecting rod piston component, eliminating the articulated joint between them. This integration removes the joint's contribution to oscillating mass and improves concentricity, directly resolving the technical contradiction by combining two separate parts into one unified structure.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a connecting rod piston with articulated joint is used, then the piston can be connected to the crankshaft, but the joint increases the number of parts to be manufactured and assembled

Engineering Contradiction:
Improvejoint structureVSAvoidassembly complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent combines the connecting rod and piston into a single integrated connecting rod piston, reducing the total number of parts that must be manufactured and assembled. This merger eliminates the need for assembling the joint connection, directly addressing the manufacturing and assembly complexity issue.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If seals are used in the connecting rod piston, then sealing is achieved, but the seals are subject to continuous wear due to transverse forces

Engineering Contradiction:
ImprovesealingVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent removes the seals from the connecting rod piston design, extracting the sealing function from a separate component. Instead, sealing is achieved through the geometric shape of the connecting rod piston itself, which eliminates the need for separate sealing elements that would be subject to wear from transverse forces.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical seal system with a geometric sealing approach. The sealing function is achieved through the precise geometric shape of the connecting rod piston and its interaction with the compression chamber walls, substituting the need for separate sealing components and their associated wear mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If the piston is shaped like a cylinder segment to maximize contact with the cylinder wall, then sealing effectiveness is enhanced, but the transverse forces acting on the cylinder walls increase wear

Engineering Contradiction:
Improvesealing effectivenessVSAvoidwear on cylinder walls
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the seals that would be pressed against the cylinder walls by transverse forces. By eliminating these separate sealing components, the harmful wear effect on the cylinder walls is reduced, while sealing effectiveness is maintained through the geometric shape of the connecting rod piston itself.

Inventive Principle:
Principle #2Taking out (Extraction)

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 simplifies the sealing concept, reduces wear on seals and cylinder walls, enhances sealing effectiveness through capillary action, and compensates for thermal changes, resulting in improved durability and reduced maintenance costs.

Implementation Method 1

a spring-elastic layer is introduced between the two parts. This layer presses the parts of the piston against the wall of the compression chamber and can thus also compensate for thermally induced changes in the piston dimensions

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a lubricant and/or combustion residues and/or particles of the medium to be conveyed or compressed collect in the two crescent-shaped gaps between the cylinder segment-shaped piston and the flat cylinder wall and are held by capillary action, so that the actual sealing effect is even higher in practice

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2247855B1Rocking piston compressor
Publication Date: 2012.02.01 WANZKE MANFRED
  • EP2247855B1 patent drawingFigure 1
  • EP2247855B1 patent drawingFigure 2
  • EP2247855B1 patent drawingFigure 3

AI summary

The invention relates to a rocking piston compressor for the intake, compression, transport or expansion and exhaust of a gaseous or fluid medium, comprising a housing with a compression chamber, with a constant profile in the direction of movement of the piston and a rocking piston, the piston part of which has a form in the stroke direction thereof which is complementary to the profile of the compression chamber and perpendicular to the stroke direction in the region contacting the compression chamber has a spherical or cylindrical segment form and the connecting rod rigidly connected to the piston has a joint to a crankshaft and at least one inlet duct and an exhaust duct, both of which are arranged in the compression chamber and both of which are opened and closed by the piston part of the rocking piston during the motion thereof, wherein the profile of the compression chamber has at least one level arranged perpendicular to the rotation al direction of the crankshaft containing all inlet ducts and exhaust ducts.