Pneumatic Mattress Blockage Detection Using Pressure and Blower Speed

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Solution Overview

Problem

Existing pneumatic systems for patient support apparatuses lack effective detection and management of intake and exhaust blockages, which can disrupt air flow and pressure, affecting patient comfort and safety.

Innovation Solution

A pneumatic system with a blower, pressure sensor, and controller that monitors pressure and blower speed to detect intake and exhaust blockages, adjusting blower speed and alerting users when conditions are outside predetermined ranges, and tracks blockage frequencies to prevent system failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If blockage detection is not implemented, then the system operates without monitoring, but air flow and pressure cannot be maintained within predetermined ranges

Engineering Contradiction:
Improveblockage detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller continuously monitors blower speed and receives input from the pressure sensor, comparing actual values against predetermined ranges. When blockage is detected through this feedback loop, the system generates alerts and adjusts blower operation, establishing a closed-loop control system that maintains reliability without excessive complexity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The pressure sensor acts as an intermediary device that indirectly detects blockage conditions by measuring pressure changes in the pneumatic enclosure. Rather than directly detecting blockages, the sensor provides pressure data that the controller uses to infer blockage status, simplifying the detection mechanism while maintaining reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If blower speed is continuously adjusted to maintain pressure, then pressure control is improved, but energy consumption increases

Engineering Contradiction:
Improvepressure control precisionVSAvoidblower energy consumption
Core Design Contradiction:
Stress or pressureVSUse of energy by moving object

Solution Approach 1:

The blower operates with variable speed control, adjusting its rotation speed dynamically based on real-time pressure feedback. The controller increases speed only when pressure drops below the predetermined range and decreases speed when pressure is adequate, creating a dynamic operation mode that optimizes energy consumption while maintaining precise pressure control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the blower (rotation speed) based on detected pressure conditions. By varying the speed parameter within a predetermined range rather than operating at constant high speed, the system achieves effective pressure control while reducing overall energy consumption during normal operation

Inventive Principle:
Principle #35Parameter changes

3Reliability

If blockage frequency is monitored, then system reliability is improved, but measurement and detection complexity increases

Engineering Contradiction:
Improvesystem failure preventionVSAvoidblockage frequency detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The controller monitors and counts blockage events continuously, maintaining a record of blockage frequency before system failures can occur. This preliminary monitoring allows the system to identify trends and potential issues early, enabling preventive maintenance actions before actual failures happen, thereby improving reliability through proactive detection

Inventive Principle:
Principle #10Preliminary action

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 system ensures optimal air flow and pressure within the pneumatic enclosure by detecting and managing blockages, maintaining patient comfort and safety by alerting caregivers and adjusting the blower speed to maintain predetermined pressure and speed ranges, thereby preventing system failures.

Implementation Method 1

A pressure sensor is configured to detect pressure within the pneumatic enclosure

Methodology Applied
Scientific EffectPressure detection:

Implementation Method 2

A blower is in fluid communication with the inlet via a first flexible conduit... A pressure sensor is configured to detect pressure within the pneumatic enclosure. A controller adjusts a speed of the blower to maintain a predetermined pressure within the pneumatic enclosure

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP3766470B1Pneumatic system blockage detection
Publication Date: 2023.04.19 HILL ROM SERVICES INC
  • EP3766470B1 patent drawingFigure 1
  • EP3766470B1 patent drawingFigure 2
  • EP3766470B1 patent drawingFigure 3

AI summary

A patient support apparatus pneumatic system (14) may include a mattress (18) defining an interior (22) and a pneumatic enclosure (26) in fluid communication with the interior (22) and comprising an inlet (30) and an outlet (34). A blower (38) may be in fluid communication with the interior (22) and the pneumatic enclosure (26). A pressure sensor (42) may be configured to detect a pressure (Pc) at the outlet (34). A controller (46) may be configured to monitor a speed of the blower (38) and the pressure at the outlet (34) for detecting at least one of an intake blockage condition (48) and an exhaust blockage condition (50).