Fluid Delivery Apparatus Using 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 varying environmental factors such as pressure and fluid viscosity, with existing flow sensors being costly and non-sterile.
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 flow rate sensors are used to measure fluid delivery, then flow rate measurement capability is provided, but the system becomes costly and cannot maintain sterile conditions
Solution Approach 1:
The patent introduces an intermediary substance (air or gas) that transmits pressure changes from the fluid chamber to an external pressure sensor. This mediator allows indirect measurement of fluid flow without requiring direct contact between the sensor and fluid, thereby maintaining sterility and reducing cost while achieving accurate flow rate measurement through pressure differential detection
Solution Approach 2:
The patent replaces conventional mechanical flow sensors with a pressure-based measurement system using air/gas as the sensing medium. This substitution eliminates the need for complex mechanical flow measurement components that must directly contact the fluid, simplifying the system while maintaining measurement capability through pressure differential analysis
2Productivity
If conventional positive displacement pumps are used, then fluid delivery is provided, but the flow rate cannot be accurately controlled when environmental conditions vary
Solution Approach 1:
The patent implements a feedback control system where pressure sensors continuously monitor the pressure differential across the pump chamber, and the controller adjusts pump operation based on this feedback to maintain accurate flow rates. The system measures actual flow through pressure differential and uses this information to correct deviations caused by environmental changes, ensuring reliable and accurate fluid delivery
Solution Approach 2:
The patent changes the operating parameters of the pump system by using variable pressure control instead of fixed displacement mechanisms. The controller dynamically adjusts pump parameters based on real-time pressure measurements, allowing the system to compensate for environmental variations and maintain accurate flow rates across different operating conditions
3Duration of action of stationary object
If diaphragm pump chambers are repeatedly filled and emptied, then continuous fluid delivery is achieved, but the system cannot accurately measure flow rate over time
Solution Approach 1:
The patent performs preliminary measurement of pressure differentials at standardized intervals during the pump cycle (such as at the end of the fill phase or delivery phase). By measuring at these predetermined time points, the system can calculate flow rate over complete pump cycles, achieving accurate measurement that accounts for the continuous nature of the pump operation while maintaining synchronization with the pump's repetitive cycle
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 accurate and reliable fluid flow control over a large range, immune to environmental factors, with real-time measurement and fast start/stop capabilities, ensuring precise and safe fluid delivery.
Implementation Method 1
a negative pressure is applied to the conventional diaphragm pump to draw fluid into a respective fluid chamber
Implementation Method 2
a positive pressure is then applied to the conventional diaphragm pump to expel the fluid from the fluid chamber
Implementation Method 3
A rotor with a number of 'rollers', 'shoes', 'wipers’, or ‘lobes’ attached to the external circumference of the rotor compresses the flexible tube
Implementation Method 4
as the tube opens to its natural state after the passing of the cam ('restitution' or 'resilience') fluid flow is induced to the pump
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.