Reciprocating Pump Cam Groove Segmentation for Flow Stability
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Solution Overview
Problem
Existing volumetric pumps with cam-driven piston mechanisms suffer from accuracy issues due to wear in plastic parts, limited durability, and inability to handle high pressures, as well as localized heating from circular seals, which restrict their use in applications requiring precise and high-pressure fluid dispensing.
Innovation Solution
A pump design featuring a single rotor with robust guiding elements outside the interchangeable fluidic module, using a cam groove with six segments to control piston movement and valve switching, allowing for accurate, durable, and high-pressure operation with reduced parts and minimal fluid contact, ensuring continuous and even flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cam-driven piston mechanisms with plastic parts are used, then the pump structure is simple and cost-effective, but the accuracy and durability deteriorate due to wear and friction
Solution Approach 1:
The pump is divided into two independent modules: a disposable fluidic module containing only pistons and cylinders, and a permanent mechanical module containing the cam, guiding elements, and driving mechanism. This segmentation allows the precision components to be made of durable materials while keeping the disposable part simple and inexpensive.
Solution Approach 2:
The critical guiding elements and cam mechanism are extracted from the disposable plastic fluidic module and placed in a permanent external mechanical module. This extraction eliminates wear issues from the disposable part while maintaining the simplicity and low cost of the fluidic module.
2Ease of manufacture
If cam-driven piston mechanisms with plastic parts are used, then the pump structure is simple, but the durability and pressure resistance deteriorate
Solution Approach 1:
The pump structure is segmented into a disposable fluidic module and a permanent mechanical module. The permanent module houses robust guiding elements and cam mechanisms made of wear-resistant materials capable of withstanding high pressures, while the fluidic module remains simple and disposable.
Solution Approach 2:
The pump combines different materials in separate modules: the fluidic module uses inexpensive plastic suitable for disposable applications, while the mechanical module uses robust, wear-resistant materials for components subjected to high pressure and friction.
3Reliability
If circular seals are used between rotor and stator, then the sealing function is achieved, but localized heating and deformation occur due to one-way circular friction
Solution Approach 1:
Instead of using a rotating circular seal that creates one-way friction and localized heating, the invention uses linear reciprocating motion with guiding elements that distribute friction evenly. The cam groove guides the piston rod linearly, eliminating the circular friction problem.
4Device complexity
If driving elements are incorporated in the interchangeable fluidic module, then the pump head is simple and disposable, but the accuracy deteriorates due to wear of plastic parts
Solution Approach 1:
The driving elements (cam mechanism and guiding elements) are extracted from the disposable fluidic module and placed in a permanent external mechanical module. This ensures that the critical accuracy-determining components are not subject to wear from disposable plastic parts.
Solution Approach 2:
The piston rod acts as an intermediary, transmitting motion from the permanent cam mechanism to the disposable piston. The guiding elements in the permanent module ensure accurate linear motion of the piston rod, which then drives the disposable piston with high precision.
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 solution provides a durable, accurate, and cost-effective pump capable of handling high pressures and maintaining consistent flow rates, suitable for applications beyond a few bar, with reduced wear and increased longevity.
Implementation Method 1
driving a rotor placed in the mechanism of the pump, provided with a guiding cam groove allowing the pistons to be displaced independently axially in the cylinder blocks via carriages
Implementation Method 2
The cylinder blocks (2,2') respectively comprise a piston (3,3') fitted with a seal
Implementation Method 3
a switching element of the valves and preferably seals
Data Source
AI summary
A pump having two pistons which are driven by a cam belonging to an external rotor and which are inserted into two cylinder blocks mounted parallel to each other in such a way as to form two opposite, parallel, eccentric pump chambers The pump chambers have at least one inlet port through which liquid is drawn into the pump chambers during the fill stroke of the pistons, and then expelled from the pump chambers during the discharge stroke of the pistons to at least one outlet port, the outflow rate of which is constant and even.