Membrane Pump Chamber for Leak-Free Precision Flow Control

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Solution Overview

Problem

Existing pump devices for hemodialysis suffer from liquid leakage at sealing parts and require additional pumps for accurate flow control.

Innovation Solution

A pump device with a chamber divided by a flexible membrane and a core member that undergoes reciprocating motion, eliminating the need for additional pumps and ensuring high accuracy in flow rate control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reciprocating metering pump with pistons and cylinders is used, then liquid delivery is enabled, but liquid leakage occurs at the sealing part between pistons and cylinders

Engineering Contradiction:
Improvesealing reliabilityVSAvoidliquid leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The pump chamber is divided into first and second areas by a dividing membrane, separating the liquid handling paths. This segmentation eliminates the need for piston-cylinder sealing interfaces that cause leakage, as the membrane provides a reliable seal between the two areas without requiring sliding seals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dividing membrane (flexible thin film) is used to separate the first and second areas within the pump chamber. This membrane provides effective sealing between the two liquid paths while allowing reciprocating motion, eliminating the liquid leakage problem associated with rigid piston-cylinder sealing arrangements.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If electromagnetic valves are used to control flow paths, then arbitrary timing control is achieved, but additional pumps are required for liquid delivery to the chamber

Engineering Contradiction:
Improveflow path controlVSAvoidnumber of pumps
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pump chamber serves dual functions: it is both the liquid delivery chamber and the actuation chamber. The dividing membrane allows the same chamber to handle both liquid delivery and provide the mechanical action for pump operation, eliminating the need for separate pumps required in electromagnetic valve-based systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single pump chamber is designed to perform multiple functions: delivering liquid through the first area and providing actuation space in the second area. This multi-functionality eliminates the need for additional pumps that would otherwise be required to pressurize the actuation chamber in electromagnetic valve systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If additional pumps are used for accurate flow rate control, then flow rate precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveflow rate control accuracyVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pump chamber integrates both liquid delivery and flow control functions in a single unit. The dividing membrane and associated valves work together within the same chamber to achieve accurate flow rate control without requiring separate additional pumps, thereby reducing device complexity and manufacturing cost while maintaining precision.

Inventive Principle:
Principle #5Merging (Combining)

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 seals the chamber effectively, eliminates the need for additional pumps, and achieves precise liquid flow control with reduced manufacturing costs.

Implementation Method 1

a dividing membrane made of a flexible member attached to the chamber, the dividing membrane dividing an inside of the chamber into a first area and a second area

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4715211A1Pump device
Publication Date: 2026.03.25 NIKKISO CO LTD
  • EP4715211A1 patent drawingFigure 1~2
  • EP4715211A1 patent drawingFigure 3
  • EP4715211A1 patent drawingFigure 4

AI summary

Provided is a pump device that includes a chamber sealed in an easy and assured manner, that eliminates the necessity for additional pumps, and that is capable of controlling the flow rate of liquid with high accuracy. A pump device 1 includes a chamber 2 capable of accommodating a predetermined volume of liquid; a dividing membrane 5 made of a flexible member attached to the chamber 2, the dividing membrane 5 dividing an inside of the chamber 2 into a first area 3 and a second area 4, the dividing membrane 5 being displaced alternately into the first area 3 and into the second area 4 to cause the liquid to be suctioned into and discharged from the first area 3 and cause drain liquid to be suctioned into and discharged from the second area 4; and a core member 6 provided to the dividing membrane 5 and configured to undergo a reciprocating motion inside the chamber 2 with activation of a motor M and in such a manner as to displace the dividing membrane 5 into the first area 3 and into the second area 4.