Rotary Pump Rotor and Diaphragm Design for Continuous Flow
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Solution Overview
Problem
Existing rotary pumps exhibit pulsating fluid flow, which can be uncomfortable in medical applications and limit throughput, and require effective sterilization for single-use systems.
Innovation Solution
A rotary pump design featuring a rotor with surface recesses and resiliently deformable diaphragms that bisect fluid flow openings, twisted or angled relative to the rotor axis, ensuring continuous fluid flow and high throughput, with materials like polypropylene and stainless steel for low friction and ease of sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a discrete number of chambers are formed by recesses in the rotor surface to convey fluid, then the pump can move fluid from inlet to outlet, but the resulting liquid flow becomes pulsated with periods of no flow and high flow
Solution Approach 1:
The rotor surface is segmented into multiple recesses forming discrete chambers, while the housing interior surface is segmented into multiple radially spaced diaphragms. This segmentation allows multiple chambers to operate simultaneously, smoothing the overall flow profile while maintaining the discrete chamber mechanism for fluid conveyance.
Solution Approach 2:
The diaphragms act as intermediaries between the rotor chambers and the housing. Each diaphragm selectively seals off portions of the chamber interior surface, mediating the interaction between the discrete chamber system and the continuous flow requirement. The diaphragms transform the pulsated flow from individual chambers into a smoother combined flow.
2Productivity
If the number of chambers is increased to improve throughput, then higher fluid flow rate is achieved, but the pump size and complexity increase
Solution Approach 1:
Multiple diaphragms are merged into a single integrated component formed as one piece, reducing the number of separate parts while maintaining the functionality of multiple individual diaphragms. This merging approach increases throughput capability without proportionally increasing device complexity.
Solution Approach 2:
The diaphragms serve multiple functions simultaneously: they seal the chambers, provide structural support for the rotor, and work together to smooth the flow profile. This multi-functionality allows the system to achieve higher throughput without adding equivalent complexity.
3Ease of manufacture
If the rotor and housing are made of sterilizable materials for single-use systems, then ease of sterilization is improved, but the friction between surfaces increases
Solution Approach 1:
The rotor and housing are made of sterilizable materials throughout, but the critical sealing surfaces between the rotor and housing are engineered with specific surface properties to minimize friction. This local quality differentiation allows the overall system to be sterilizable while maintaining low friction at the interface where friction matters most.
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 pump provides continuous fluid flow with reduced pulsation, higher throughput, and ease of sterilization, suitable for medical and single-use applications.
Implementation Method 1
a plurality of resiliently deformable diaphragms each providing part of the interior surface of the housing, the rotor engaging surface of each diaphragm being urged into contact with the rotor by the action of a pressurising means acting on the rear surface of the diaphragm
Implementation Method 2
a surface recess that forms with said interior surface of the housing a fluid-conveying chamber that, on rotation of the rotor, conveys fluid from the first fluid port to the second fluid port
Implementation Method 3
the rotor being twisted about the longitudinal axis of rotation thereof, such that the first end and the second end of the rotor are rotationally off-set relative to one another by at least 10 degrees
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The present application relates to rotary pumps, which in some embodiments provide continuous flow. In particular, the present application relates to pumps comprising, a first fluid port and a second fluid port, a housing having an interior surface defining a cavity in which a rotor is located, a rotor, being rotatably mounted within the housing and having a longitudinal axis of rotation, and comprising, a housing engaging surface area forming a sealing interference fit with the interior surface of the housing, and a surface recess that forms with said interior surface of the housing a fluid-conveying chamber that, on rotation of the rotor, conveys fluid from the first fluid port to the second fluid port, a resiliently deformable diaphragm providing part of the interior surface of the housing, each diaphragm comprising a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of each diaphragm being urged into contact with the rotor by the action of a pressurising means acting on the rear surface of the diaphragm, the rotor comprising an elongate body and a drive shaft, which body is substantially hollow and comprises separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor body further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity, the pump being arranged such that when the rotor body is located within the housing cavity, the first fluid port is in fluid flow communication with the first rotor cavity via the opening at the first end of the rotor, and the second fluid port is in fluid flow communication with the second rotor cavity via the opening at the second end of the rotor, and the pump being arranged such that the resiliently deformable diaphragm always bisects the first opening and the second opening on the rotor surface recess as the rotor rotates. In some embodiments the rotor may be twisted about the longitudinal axis of rotation thereof, such that a first end and a second end of the rotor are rotationally off-set relative to one another by at least 10 degrees.