Peristaltic Pump Pressure Detection via Radial Displacement

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Solution Overview

Problem

Existing pressure detection devices in liquid flow routes, such as those used in hemodialysis circuits, face issues with liquid stagnation and increased manufacturing costs due to the need for separate flexible hollow members, which also increase the priming volume.

Innovation Solution

A pressure detection device that utilizes a peristaltically-actuated tube with a gripping device and displacement detection mechanism, allowing for radial displacement detection without the need for additional devices connected to the liquid flow route, using a torsion spring to grip and detect pressure changes in the peristaltically-actuated tube.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate flexible hollow member is connected to the blood circuit to detect pressure, then pressure detection is enabled, but liquid stagnation occurs and manufacturing cost increases

Engineering Contradiction:
Improvepressure detectionVSAvoidliquid stagnation
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent combines the pressure detection function with the existing peristaltic pump structure by detecting radial displacement of the peristaltically-actuated tube during pumping operation. This eliminates the need for a separate flexible hollow member connected to the blood circuit, thereby preventing liquid stagnation while maintaining pressure detection capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The peristaltically-actuated tube serves dual functions: it acts as both the pumping element and the pressure sensing element. By monitoring its radial displacement during compression and relaxation cycles, the system obtains pressure information without requiring a dedicated sensing component that would otherwise be needed.

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

2Measurement precision

If a separate flexible hollow member is connected to the blood circuit to detect pressure, then pressure detection is enabled, but manufacturing cost increases

Engineering Contradiction:
Improvepressure detectionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the pressure detection functionality into the existing peristaltic pump system by utilizing the peristaltically-actuated tube's inherent mechanical properties. This integration eliminates the need for separate pressure sensing components and their associated connections, thereby reducing manufacturing complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The peristaltically-actuated tube provides self-sensing capability through its own radial displacement during the pumping cycle. The tube's natural mechanical response to internal pressure changes during compression and relaxation serves as the sensing mechanism, eliminating the need for external sensing hardware.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a separate flexible hollow member is connected to the blood circuit to detect pressure, then pressure detection is enabled, but the capacity of the liquid flow route increases

Engineering Contradiction:
Improvepressure detectionVSAvoidliquid flow route capacity
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent integrates pressure detection within the existing peristaltic pump structure by monitoring the radial displacement of the peristaltically-actuated tube. This approach eliminates the need for additional flexible hollow members or expansion chambers that would increase the liquid flow route capacity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The peristaltically-actuated tube serves as both the pumping element and the pressure sensing element through its own mechanical deformation. This self-sensing mechanism requires no additional volume for pressure detection, maintaining the minimal liquid flow route capacity.

Inventive Principle:
Principle #25Self-service

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 solution reduces liquid stagnation and manufacturing costs by integrating pressure detection into the peristaltic pump, enabling accurate monitoring of pressure changes without additional equipment, thus enhancing the efficiency and reliability of blood purification treatments.

Implementation Method 1

a peristaltic pump, and a peristaltically-actuated tube 1a which can cause an internal liquid to flow by being compressed in a radial direction and by being peristaltically actuated in a longitudinal direction in a peristaltic unit of a peristaltic pump

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

a biasing device which biases the gripping piece against the peristaltically-actuated tube side, and wherein (i) the displacement detection device detects a load applied to a fixing end side of the biasing device

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2749858B1Fluid flow path pressure detection device
Publication Date: 2018.04.25 NIKKISO CO LTD
  • EP2749858B1 patent drawingFigure 1
  • EP2749858B1 patent drawingFigure 2
  • EP2749858B1 patent drawingFigure 3~4

AI summary

[Object] To provide a pressure detection device which can suppress stagnation of a circulating liquid and decrease the manufacturing cost and the capacity (priming volume) of a liquid flow route. [Solution] A pressure detection device of a liquid flow route is provided which detects a pressure of an arterial blood circuit 1 consisting of a flexible tube, a portion of which is connected to a peristaltically-actuated tube 1a that can cause an internal liquid to flow by being compressed in a radial direction and being peristaltically actuated in a longitudinal direction in a roller 10 of a blood pump 4, and which enables a predetermined liquid to be circulated. The pressure detection device includes a load sensor 18 that detects radial displacement of the peristaltically-actuated tube 1a.