Free Piston Linear Motor Compressor Without Mechanical Springs

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Solution Overview

Problem

Existing natural gas compressors face high manufacturing and maintenance costs, short operational lifespan, and are unsuitable for applications requiring high purity and elevated pressures due to their reliance on mechanical or electromagnetic components.

Innovation Solution

A Free Piston Linear Motor Compressor (FPLMC) system with a multi-stage dual-acting piston driven by a linear motor, eliminating mechanical springs and electromagnetic coils, and utilizing a piston position feedback control system to maintain stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If reciprocating compressor technology with rotational motor and crankshaft is used, then compression function is achieved, but manufacturing cost and maintenance cost increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidoperational lifespan
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts and eliminates the crankshaft mechanism from the compressor system, using a linear motor to directly drive the piston in linear reciprocating motion. This removal of the crankshaft simplifies the mechanical structure, reduces manufacturing complexity and cost, while simultaneously improving reliability by eliminating a major source of mechanical wear and failure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional rotational motor-crankshaft mechanical transmission system with a linear motor that directly generates linear motion. This substitution eliminates the need for mechanical conversion mechanisms, reducing the number of moving parts and mechanical losses, thereby lowering manufacturing costs and extending operational lifespan.

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

2Device complexity

If mechanical springs or electromagnetic coils are used for piston stability, then piston centering is achieved, but device complexity increases

Engineering Contradiction:
Improvemechanical componentsVSAvoidpiston stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent replaces mechanical springs and electromagnetic coils with an active control system that uses position feedback and adaptive current output from the linear motor to maintain piston stability. This substitution eliminates complex mechanical centering mechanisms while achieving equivalent or superior stability through electronic control.

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

Solution Approach 2:

The patent implements a feedback control system that monitors piston position and adjusts motor current accordingly to maintain stable operation. This feedback mechanism enables the system to achieve piston centering and stability without requiring mechanical springs or additional electromagnetic coils, thereby reducing device complexity.

Inventive Principle:
Principle #23Feedback

3Ease of repair

If traditional compressor design with multiple moving parts is used, then compression function is achieved, but maintenance cost increases

Engineering Contradiction:
Improvemaintenance costVSAvoidnumber of moving parts
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The patent extracts and removes the crankshaft and associated connecting rods from the compressor system, replacing them with a linear motor that directly drives the piston. This extraction of unnecessary mechanical components significantly reduces the number of moving parts that require maintenance, thereby lowering maintenance costs while simplifying the overall device structure.

Inventive Principle:
Principle #2Taking out (Extraction)

4Loss of energy

If reciprocating compressor with crankshaft is used, then gas compression is achieved, but mechanical parasitic losses increase

Engineering Contradiction:
Improvemechanical parasitic lossesVSAvoidmechanical transmission components
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces the rotational motor-crankshaft mechanical transmission system with a linear motor that directly generates linear reciprocating motion. This substitution eliminates the mechanical energy losses associated with crankshaft rotation, connecting rod motion, and bearing friction, thereby significantly reducing mechanical parasitic losses and improving overall system efficiency.

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

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 FPLMC reduces manufacturing and maintenance costs, increases durability, and allows for stable operation at any point in the stroke, achieving efficient gas compression with reduced complexity and size, suitable for high-pressure applications.

Implementation Method 1

a linear electric motor positioned to reciprocate the piston

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 2

a piston position feedback control system configured to provide adaptive current output as a function of position feedback and/or velocity feedback from the piston

Methodology Applied
Scientific EffectFeedback: Feedback

Data Source

PatentEP3698046B1Free piston linear motor compressor and associated systems of operation
Publication Date: 2023.04.19 GAS TECH INST
  • EP3698046B1 patent drawingFigure 1~2
  • EP3698046B1 patent drawingFigure 3
  • EP3698046B1 patent drawingFigure 4

AI summary

A linear motor compressor including a compressor housing and a cylinder housing having a plurality of opposing compression chambers. A piston freely reciprocates within the cylinder housing using a linear electric motor. A piston position feedback control system provides adaptive current output as a function of position feedback and/or velocity feedback from the piston and/or the electric motor, to directly power and control the electric motor, wherein the piston reciprocates without assistance from a mechanical spring or other equivalent centering force.