Vacuum Pump Current Sensing for Wound Vacuum Control
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Solution Overview
Problem
Existing negative pressure wound therapy devices fail to accurately control vacuum pressure levels, are not patient-friendly in terms of size, noise, and power consumption, and lack efficient exudate management, while ignoring the impact of voltage variations and temperature on motor current draw.
Innovation Solution
A method and apparatus that monitor current amplitude and temperature to control vacuum pressure, using a look-up table to correlate current with pressure, and intermittently operate the pump to maintain optimal pressure levels, with exudate management through a disposable container system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a vacuum pump system is designed to be compact and portable, then mobility and space efficiency are improved, but cooling performance and heat dissipation capability deteriorate
Solution Approach 1:
The pump system is divided into separate functional modules: a pump housing containing the vacuum pump, and a separate cooling assembly with its own housing. This segmentation allows each module to be optimized independently - the pump housing can be compact while the cooling assembly can be designed with adequate heat dissipation surfaces and airflow pathways.
Solution Approach 2:
The cooling assembly utilizes vertical airflow pathways and stacked component arrangement to maximize heat dissipation surface area within a compact footprint. The plenum chamber extends vertically to accommodate airflow from bottom to top, allowing efficient cooling without requiring large horizontal space.
2Device complexity
If the pump housing and drive assembly are integrated, then device complexity is reduced, but serviceability and maintenance access deteriorate
Solution Approach 1:
The system is divided into a pump housing and a separate cooling assembly that can be independently accessed and serviced. The cooling assembly can be removed or accessed without disassembling the entire pump system, enabling maintenance of cooling components while preserving the integrated design benefits for the vacuum generation portion.
3Temperature
If a separate cooling assembly is added, then cooling performance is improved, but device complexity and number of components increase
Solution Approach 1:
The cooling assembly integrates multiple cooling functions into a single unit: the plenum chamber serves as both a structural housing and a thermal management component, the fan assembly combines motor and impeller functions, and the side walls of the plenum chamber serve as heat dissipation surfaces. This merging reduces the number of separate components compared to traditional distributed cooling systems.
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
Accurately controls vacuum pressure, minimizes device size and noise, extends battery life, and ensures efficient exudate handling, while being adaptable to temperature variations and system malfunctions.
Implementation Method 1
a fan assembly positioned within the cooling assembly and configured to move air through the cooling assembly
Implementation Method 2
a pump housing configured to receive a vacuum pump, the vacuum pump being positioned within the pump housing and configured to reduce pressure within the chamber
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A negative pressure wound therapy system wherein an electrically driven air pump, powered by a constant voltage source, is used to establish a negative pressure at a wound site, and the amplitude of the current, supplied to a motor driving the pump, after adjustment to take account of the effect of operating temperature, and no load current of the motor, is used at intervals to determine the vacuum level prevailing at the wound site.