Variable-Interference Stator for Pulsation-Reduced Fluid Transfer

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Solution Overview

Problem

Existing fluid transfer devices using a uniaxial eccentric screw pump experience pulsation during fluid discharge, leading to non-uniform discharge and pulsating flow in circulation circuits, which affects the consistency of fluid application on work surfaces.

Innovation Solution

A fluid transfer device with a stator design that varies contact force and interference along its length, featuring smaller contact forces and interference at the inlet and outlet portions compared to the central portion, ensuring uniform fluid transfer by adjusting the stator's material properties and shape to minimize pulsation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a uniaxial eccentric screw pump is used to transfer fluid, then fluid transport capability is improved, but pulsation occurs during discharge leading to non-uniform discharge

Engineering Contradiction:
Improvefluid transport capabilityVSAvoiddischarge uniformity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The stator is designed with varying interference amounts along its longitudinal direction. Specifically, the interference amount is smaller at the inlet portion and outlet portion compared to the central portion. This local variation in interference creates different contact forces at different locations, which stabilizes the rotor-stator contact and eliminates discharge pulsation while maintaining fluid transport capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the interference parameter of the stator along its length. By making the interference amount smaller at the inlet and outlet portions compared to the central portion, the contact force distribution is optimized. This parameter variation prevents excessive contact force at critical locations that would cause pulsation, while maintaining sufficient contact force in the central portion for effective fluid transport

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the stator has uniform interference throughout, then manufacturing is simplified, but contact force distribution causes pulsation and non-uniform discharge

Engineering Contradiction:
Improvestator manufacturing simplicityVSAvoiddischarge stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The stator is designed with varying interference amounts along its longitudinal direction. Specifically, the interference amount is smaller at the inlet portion and outlet portion compared to the central portion. This local variation in interference creates different contact forces at different locations, which stabilizes the rotor-stator contact and eliminates discharge pulsation while maintaining fluid transport capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the interference parameter of the stator along its length. By making the interference amount smaller at the inlet and outlet portions compared to the central portion, the contact force distribution is optimized. This parameter variation prevents excessive contact force at critical locations that would cause pulsation, while maintaining sufficient contact force in the central portion for effective fluid transport

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the device is used in a fluid circulation circuit, then fluid circulation is achieved, but pulsating flow occurs instead of constant flow

Engineering Contradiction:
Improvefluid circulation capabilityVSAvoidflow constancy
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The stator is designed with varying interference amounts along its longitudinal direction. Specifically, the interference amount is smaller at the inlet portion and outlet portion compared to the central portion. This local variation in interference creates different contact forces at different locations, which stabilizes the rotor-stator contact and eliminates discharge pulsation while maintaining fluid transport capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the interference parameter of the stator along its length. By making the interference amount smaller at the inlet and outlet portions compared to the central portion, the contact force distribution is optimized. This parameter variation prevents excessive contact force at critical locations that would cause pulsation, while maintaining sufficient contact force in the central portion for effective fluid transport

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the device discharges liquid material onto a work surface, then coating application is achieved, but pulsation causes non-uniform line width

Engineering Contradiction:
Improvecoating application capabilityVSAvoidline width uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The stator is designed with varying interference amounts along its longitudinal direction. Specifically, the interference amount is smaller at the inlet portion and outlet portion compared to the central portion. This local variation in interference creates different contact forces at different locations, which stabilizes the rotor-stator contact and eliminates discharge pulsation while maintaining fluid transport capability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the interference parameter of the stator along its length. By making the interference amount smaller at the inlet and outlet portions compared to the central portion, the contact force distribution is optimized. This parameter variation prevents excessive contact force at critical locations that would cause pulsation, while maintaining sufficient contact force in the central portion for effective fluid transport

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

The device achieves consistent fluid discharge and reduces pulsation, enabling uniform line widths on work surfaces and stable fluid circulation.

Implementation Method 1

The stator of the device has interference for tightening (interference) that elastically deforms due to rotation of the rotor, and transports the liquid material or fluid by taking advantage of the elastic action of the stator.

Methodology Applied
Scientific EffectElastic action: Elasticity

Data Source

PatentEP4282539B1Fluid transfer device, coating device comprising same, and coating method
Publication Date: 2025.07.23 MUSASHI ENG INC
  • EP4282539B1 patent drawingFigure 1~2(f)
  • EP4282539B1 patent drawingFigure 3(a)~4(b)
  • EP4282539B1 patent drawingFigure 5(a)~5(e)

AI summary

Problem: To provide a fluid transfer device that can solve an issue of pulsation that occurs when a liquid material is discharged from a nozzle by eccentrically rotating a male-screw-shaped rotor within a stator having a female-screw-shaped insertion hole, an application device including the fluid transfer device, and an application method. Solution: A fluid transfer device 1 includes: an outer cylinder 10; a stator 11 that has a female-screw-shaped insertion hole 12 as a through-hole and is provided on an inner periphery of the outer cylinder; and a male-screw-shaped rotor 20 that is connected to a rotor driving part and eccentrically rotates in contact with an inner periphery of the stator. In the fluid transfer device 1 capable of transferring a fluid in a transport path formed by the stator 11 and the rotor 20, by rotating the rotor 20 inserted through the insertion hole 12, contact force with the rotor 20 at an inlet portion and an outlet portion of the stator 11 is smaller than contact force with the rotor 20 at a central portion of the stator 11.