Dual-Stage Fluidics System Reducing Pulsation
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Solution Overview
Problem
Existing fluid handling systems, particularly in medical research instruments like flow cytometers, face challenges in achieving a consistent and constant fluid flow due to the pulsatile nature of pumps, leading to difficulties in maintaining stable pressure and flow rates.
Innovation Solution
A dual-stage fluidics system utilizing two pressurized reservoirs and peristaltic pumps to maintain a predetermined amount of sheath fluid and air pressure, with sensors and control systems to modulate pump operations and air supply, ensuring minimal pressure variation between reservoirs and stable fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single peristaltic pump is used to deliver sheath fluid, then the system is simple and inexpensive, but the fluid flow is pulsatile and pressure is unstable
Solution Approach 1:
The single pump system is segmented into a dual-pump configuration where the first peristaltic pump delivers sheath fluid to the first reservoir and the second peristaltic pump delivers sheath fluid to the second reservoir. This segmentation allows each pump to operate independently, reducing the pulsatile effects and improving flow stability while maintaining reasonable system complexity
Solution Approach 2:
Two pressurized reservoirs are introduced as intermediary components between the pumps and the flow cytometer. These reservoirs act as buffers that dampen pressure pulsations from the peristaltic pumps and provide stable hydrostatic pressure to the system, thereby improving fluid flow stability without requiring complex active pressure control mechanisms
2Stability of the object's composition
If large reservoirs and expensive air regulators are used to reduce pulsation, then fluid flow stability improves, but system cost and size increase
Solution Approach 1:
The system uses the natural hydrostatic pressure from the vertically positioned reservoirs to provide stable fluid delivery without requiring expensive active pressure regulation systems. The reservoirs self-regulate pressure based on their height and fluid weight, eliminating the need for costly electronic pressure controllers while maintaining excellent pressure stability
Solution Approach 2:
The system utilizes pneumatic pressurization of the reservoirs (using small peristaltic pumps to maintain air pressure above the fluid) combined with hydraulic principles to achieve stable fluid delivery. This approach replaces expensive electronic pressure regulators with simple pneumatic-hydraulic pressure transmission, significantly reducing system cost while maintaining pressure stability
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 achieves a low-pulsatility fluid flow with minimal pressure fluctuations, suitable for precise applications like flow cytometry, by maintaining consistent fluid and air pressures within 1% of each other, reducing the need for expensive air regulators and large reservoirs.
Implementation Method 1
pumping sheath fluid into a first pressurized reservoir using a first peristaltic sheath fluid pump
Implementation Method 2
pulsatile nature of the pump
Implementation Method 3
maintaining a predetermined amount of the sheath fluid in the first pressurized reservoir
Implementation Method 4
supplying air to the first pressurized reservoir using an air pump to pressurize the first pressurized reservoir
Data Source
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AI summary
A system for generating a low-pulsatility fluid flow comprises: a first pressurized reservoir (106); a second pressurized reservoir (126); a fluid sensor (128) that generates a quantity signal in response to an amount of the fluid in the second pressurized reservoir (126); a peristaltic fluid pump (118) for pumping fluid from the first pressurized reservoir (106) to the second pressurized reservoir (126); and a peristaltic air pump for pumping air between the first pressurized reservoir (106) and the second pressurized reservoir (126). The system is configured to modulate the operation of the peristaltic fluid pump (118) in response to the fluid quantity signal generated by the fluid sensor (128) so as to maintain a predetermined amount of fluid in the second pressurized reservoir (126), and configured to pump air between the first pressurized reservoir (106) and the second pressurized reservoir (126) so as to maintain both pressurized reservoirs (106, 126) at a substantially even pressure so that fluid pulsations are reduced. The corresponding method of generating a low-pulsatile fluid flow is also disclosed.