Centrifugal Pump Suction Pressure Detection

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Solution Overview

Problem

Existing extracorporeal blood circulation systems with centrifugal pumps face challenges in reliably detecting excessive vacuum on the suction side without using pressure sensors, which can lead to air penetration and patient safety risks.

Innovation Solution

A device equipped with a flow sensor, pressure sensor on the discharge side, and an evaluation unit that determines the suction side pressure using measurement signals from these sensors and the rotational speed of the centrifugal pump, allowing for reliable vacuum detection and alerting operators or adjusting pump operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure sensor is placed on the venous side of the pump to detect vacuum, then vacuum detection is possible, but air can penetrate into the blood circulation system through leaks at the sensor site

Engineering Contradiction:

Improvevacuum detectionVSAvoidair penetration

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary calculation method that uses discharge side pressure sensor data combined with pump characteristics (head curve) to indirectly determine suction side vacuum pressure. This intermediary approach eliminates the need for direct pressure sensing on the venous side, thereby preventing air penetration through potential sensor leaks while maintaining accurate vacuum detection capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical pressure sensing system on the venous side with a computational system that calculates vacuum pressure based on discharge side measurements and pump performance characteristics. This substitution eliminates the physical pressure sensor on the vulnerable venous side, replacing it with an electronic calculation that achieves the same measurement function without the harmful leak pathway.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the centrifugal pump operates at high suction power, then blood pumping efficiency is improved, but excessively high vacuum occurs in the venous hose line causing blood damage

Engineering Contradiction:

Improveblood pumping efficiencyVSAvoidblood damage from excessive vacuum

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback control system where the evaluation unit continuously monitors discharge side pressure and pump rotational speed, calculates suction side vacuum pressure in real-time, and provides feedback signals to control the pump operation. When excessive vacuum is detected, the system can automatically adjust pump speed or alert the operator, preventing blood damage while maintaining optimal pumping efficiency during normal operation.

Inventive Principle:

Principle #23Feedback

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

Enables reliable detection and management of excessive vacuum on the suction side, preventing air penetration and ensuring patient safety by accurately determining suction side pressure without direct pressure sensing on the venous side.

Implementation Method 1

a flow sensor which detects the discharged quantity on the discharge side of the pump and outputs a measurement signal corresponding to the discharged quantity

Methodology Applied

Scientific EffectFluid flow detection:

Implementation Method 2

a pressure sensor which detects the pressure on the discharge side of the pump and outputs a measurement signal corresponding to the pressure

Methodology Applied

Scientific EffectPressure detection:

Implementation Method 3

a centrifugal pump that sucks in the blood to be pumped via a venous hose line connected to the suction side of the pump and discharges the blood via an arterial hose line connected to the discharge side of the pump

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS9452250B2Device for pumping blood in an extracorporeal circuit

Publication Date: 2016.09.27 LIVANOVA DEUT GMBH

AI summary

A device for pumping blood in an extracorporeal circuit includes a centrifugal pump that suctions the blood to be pumped via a venous hose line connected to a suction side of the pump and releases it via an arterial hose line connected to a release side of the pump. The device includes a flow sensor that detects a released quantity on the release side of the pump and emits a measurement signal corresponding to the released quantity, a pressure sensor that detects the pressure on the release side of the pump and emits a measurement signal corresponding to the pressure, and an evaluation unit to which the measurement signals of the sensors are fed and which determines a value corresponding to the pressure on the suction side of the pump, taking into consideration the two measurements signals and the rotational speed of the centrifugal pump.