Pulsation-Free Rotary Pump with Cam-Guided Dual Pistons
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Solution Overview
Problem
Existing rotary piston pumping systems are costly to manufacture and maintain, unsuitable for use in medical or food environments due to complex parts and spring-loaded valves, and produce pulsation-free flow discontinuously, making them impractical for low-cost disposable fluidic modules.
Innovation Solution
A pulsation-free positive displacement pump design featuring two parallel pistons in a rotor with a cam-guided stator, utilizing a minimal number of parts made from easily injection-molded plastic, ensuring a high-performance, pulsation-free flow at variable rates without additional elements for port connection synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional rotary piston pumping systems are used, then pumping function is achieved, but manufacturing and maintenance costs are high due to numerous parts
Solution Approach 1:
The pump is divided into two independent piston-cylinder assemblies that can be manufactured separately and then assembled. Each assembly has its own piston, cylinder, and valve components, allowing for simplified manufacturing processes and easier replacement of individual segments if needed.
Solution Approach 2:
The two piston-cylinder assemblies are combined within a single housing structure, sharing common components such as the valve mechanism and drive shaft. This merging reduces the total number of parts while maintaining the pumping function, directly addressing the contradiction between manufacturing simplicity and functional capability.
2Reliability
If spring-loaded valves are employed for the distributor, then flow control is achieved, but the system becomes unsuitable for injection-molded plastic parts with elastomer seals
Solution Approach 1:
The traditional spring-loaded valve mechanism is replaced with a cam-operated valve system. The cam profile is designed to directly control the valve timing and opening, eliminating the need for complex spring mechanisms. This substitution allows for easier integration with injection-molded plastic components and elastomer seals, as the cam mechanism can be directly formed as part of the plastic housing.
3Productivity
If discontinuous alternating operating cycle is used, then pumping action is achieved, but pulsation-free flow cannot be produced
Solution Approach 1:
The pump design ensures continuous flow by coordinating the operation of two piston-cylinder assemblies out of phase with each other. While one piston is in the power stroke delivering fluid, the other piston is in the suction stroke, ensuring that fluid is continuously delivered to the outlet without interruption. This continuous operation eliminates pulsations while maintaining high pumping productivity.
Solution Approach 2:
The pump utilizes periodic action through the alternating operation of two pistons in a coordinated sequence. The cam mechanism ensures that the valves open and close in a periodic manner that synchronizes with the piston motion, creating a smooth, continuous flow output despite the periodic nature of individual piston cycles.
4Reliability
If complex systems with multiple parts are used, then pumping function is achieved, but maintenance costs are high
Solution Approach 1:
The pump is segmented into modular piston-cylinder assemblies that can be independently removed and replaced. This segmentation allows for easy maintenance and repair, as individual components can be replaced without discarding the entire pump assembly, directly reducing maintenance costs while maintaining reliable pumping function.
Solution Approach 2:
The pump is designed with disposable plastic components that can be easily replaced rather than repaired. The injection-molded plastic parts, including the housing and valve components, are designed to be cost-effective replacements, eliminating the need for expensive maintenance repairs and reducing overall maintenance costs.
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 achieves simplified mass production with low-cost, disposable components, ensuring continuous and uninterrupted flow, suitable for medical and food applications, while reducing manufacturing and maintenance costs.
Implementation Method 1
move the pistons axially in the rotor via the cam located on the interior wall of the stator
Implementation Method 2
a housing for a sealing element positioned between the rotor and the stator
Data Source
AI summary
A pump having two pistons placed in a rotor, situated in a stator forming two opposite parallel eccentric pumping chambers having at least one inlet port through which the fluid is drawn into at least one of the pumping chambers during the filling movement of at least one of the pistons and, subsequently, expelled from at least one of the pumping chambers, during the emptying movement of at least one of the pistons, to at least one outlet port, characterized by an inlet cavity in connection with the inlet port, an outlet cavity in connection with the outlet port and two port changeover transition zones situated between each side of the cavities.