Fluid Delivery Apparatus Using Nested Diaphragm and Positive Displacement Pumps
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Solution Overview
Problem
Conventional fluid pumps lack the ability to accurately measure and monitor the flow rate of fluid delivery to patients, especially over a wide dynamic range, and are prone to errors due to variations in environmental factors such as pressure and fluid viscosity, which can lead to inconsistent and unreliable delivery.
Innovation Solution
A fluid delivery apparatus comprising a pneumatically driven diaphragm pump and a positive displacement pump, where a controller measures the flow rate by tracking the fluid remaining in the diaphragm pump's chamber over time, allowing for precise control of fluid flow rates from 0.1 to 1200 ml/hr and immunity to pressure and viscosity changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional diaphragm pumps or peristaltic pumps are used for fluid delivery, then the pump structure is simple and easy to manufacture, but the flow rate measurement precision is poor and cannot accurately monitor delivery rates over a wide dynamic range
Solution Approach 1:
The patent implements a nested pump configuration where a peristaltic pump is positioned inside a diaphragm pump. The peristaltic pump handles precise flow rate control and measurement, while the diaphragm pump provides bulk fluid delivery. This nested arrangement allows the system to achieve high measurement precision without requiring a completely new complex pump design, as it leverages the strengths of two existing pump types in a hierarchical structure.
Solution Approach 2:
The patent introduces a flow sensor as an intermediary component that measures the actual flow rate of fluid delivery. This sensor acts as a mediator between the pump mechanism and the control system, providing real-time feedback on flow rate. The controller uses this feedback to adjust pump operation and maintain accurate flow delivery, thereby achieving high measurement precision without requiring the pump itself to be highly complex.
2Reliability
If conventional positive displacement pumps are calibrated at fixed conditions, then the device complexity is low, but the reliability of fluid delivery deteriorates when environmental factors such as pressure and viscosity change
Solution Approach 1:
The patent implements a closed-loop feedback control system where a flow sensor continuously measures the actual flow rate and provides feedback to the controller. The controller compares the measured flow rate with the desired flow rate and adjusts the pump operation accordingly. This feedback mechanism ensures reliable and consistent fluid delivery even when environmental factors such as pressure and viscosity change, as the system automatically compensates for these variations.
Solution Approach 2:
The patent transitions from static calibration to dynamic flow rate control. Instead of relying on fixed calibration conditions, the system continuously monitors and adjusts the flow rate in real-time based on actual operating conditions. The controller dynamically modifies pump parameters such as rotation speed or diaphragm actuation frequency to maintain the desired flow rate despite changes in pressure, viscosity, or other environmental factors.
3Measurement precision
If the flow rate of conventional pumps is affected by changes in inlet pressure, outlet back pressure, and fluid viscosity, then the ease of operation is high, but the measurement precision of flow rate deteriorates
Solution Approach 1:
The patent employs a flow sensor that directly measures the actual flow rate of fluid delivery, providing accurate measurement independent of inlet pressure, outlet back pressure, or fluid viscosity changes. This measurement feedback is sent to the controller, which adjusts pump operation to maintain the desired flow rate. This approach achieves high measurement precision without significantly complicating operation, as the system automatically compensates for varying conditions.
Solution Approach 2:
The patent replaces reliance on mechanical pump characteristics and calibration with electronic sensing and control. Instead of depending on the mechanical design of the pump to maintain accurate flow delivery under varying conditions, the system uses electronic flow sensors and controllers to measure and adjust flow rate. This substitution of mechanical precision with electronic measurement and control achieves high measurement precision while maintaining ease of operation through automated control.
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 provides accurate and reliable fluid flow control over a large dynamic range, ensuring consistent delivery rates and real-time measurement, reducing the risk of errors caused by environmental factors.
Implementation Method 1
a pneumatically driven diaphragm pump... drawing a fluid from a fluid source into a chamber of a diaphragm pump via application of negative pressure... applying a positive pressure to the chamber causing the fluid in the chamber to be delivered
Implementation Method 2
a positive displacement pump, where a controller measures the flow rate by tracking the fluid remaining in the diaphragm pump's chamber over time
Data Source
AI summary
A fluid delivery apparatus includes controller hardware, a diaphragm pump, a positive displacement pump, and a fluid conduit extending between the diaphragm pump and the positive displacement pump. During operation, and delivering fluid to a downstream recipient, the controller hardware draws fluid into a chamber of the diaphragm pump from a fluid source container. The controller hardware applies pressure to the chamber of the diaphragm pump to output the fluid in the chamber of the diaphragm pump downstream through the fluid conduit to the positive displacement pump. During application of the pressure to the chamber and outputting the fluid in the chamber of the diaphragm pump downstream, the controller hardware activates the positive displacement pump to pump the fluid from the positive displacement pump to the downstream recipient.