Multi-Cavity Diaphragm Pump Layout for Air Purging and Low Pulsation
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Solution Overview
Problem
Existing diaphragm pumps face issues with air trapping and pressure pulsation, particularly at low flow rates, which affect the accuracy and efficiency of fluid transfer in bioprocessing applications.
Innovation Solution
A diaphragm pump design with a configuration where outlet valves are positioned above inlet valves in each cavity, allowing for effective air purging and reduced pulsation, featuring a common inlet and outlet with moveable diaphragms and flexible valve disks for precise fluid displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If outlet openings are provided at high positions for venting and low positions for draining, then venting and draining functions are supported, but air trapping occurs at low flow rates because the valve cannot open properly
Solution Approach 1:
The outlet valve is divided into multiple independent outlet openings (first outlet opening, second outlet opening, etc.) positioned at different heights within the pump cavity. Each opening can open and close independently based on local pressure conditions, allowing the valve to perform both venting (through upper openings) and draining (through lower openings) functions simultaneously without air trapping
Solution Approach 2:
Different outlet openings are positioned at different local positions (high and low positions) within the pump cavity to create localized flow paths. The upper outlet openings facilitate venting of trapped air while lower outlet openings enable draining of liquid, with each opening optimized for its specific function based on its local position
2Device complexity
If a single pump is used instead of multiple pumps, then cost and ease of maintenance are improved, but pressure pulsation increases
Solution Approach 1:
Multiple pump cavities are merged into a single pump head assembly that operates simultaneously. The pump head includes multiple cavities (first cavity, second cavity, third cavity) with their own diaphragms and valve assemblies, all working together in one integrated unit to provide continuous flow with reduced pulsation while maintaining the simplicity of a single pump system
Solution Approach 2:
The pump employs multiple cavities operating in alternating cycles where each cavity undergoes sequential filling and discharge phases. This periodic action across multiple cavities smooths out pressure fluctuations and reduces overall pulsation in the output flow
3Object-generated harmful factors
If outlet valves are positioned above inlet valves, then air purging is improved, but device complexity increases
Solution Approach 1:
The valve assembly exhibits asymmetric positioning where outlet valves are deliberately positioned above inlet valves within each pump cavity. This asymmetric arrangement creates a natural air purging path where air bubbles rise to the upper outlet valve position and are expelled, while liquid flows through the lower inlet valve, simplifying the overall design without requiring additional air removal mechanisms
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 design ensures high accuracy and linearity in fluid transfer, with improved sanitization and reduced pulsation, even at low flow rates, making it suitable for single-use applications and cost-effective.
Implementation Method 1
a first outlet valve (11) and a second outlet valve (11) arranged at different positions in the pump cavity (7)
Implementation Method 2
moveable diaphragms provided in said pump cavities for varying a volume of the pump cavities
Implementation Method 3
a centre of the outlet valve for each pump cavity is positionable above a centre of the inlet valve for the same pump cavity when the diaphragm pump is oriented for use to inhibit trapped gas
Data Source
AI summary
A diaphragm pump for a bioprocess system comprises a pump head (1; 101; 201; 301) comprising: a common inlet (3); a common outlet (5); a plurality of pump cavities (7) each including at least one cooperating pair of one-way valves, the at least one pair of one-way valves including an inlet valve (9) and an outlet valve (11), wherein the respective inlet valves (9) are in fluid communication with the common inlet (3) and the respective outlet valves (11) are in fluid communication with the common outlet (5) and wherein a centre of the outlet valve (11) for each pump cavity is positionable above a centre of the inlet valve (9) for the same pump cavity when the diaphragm pump is oriented for use to inhibit trapped gas; and a plurality of moveable diaphragms (13) each respectively provided in a respective of said pump cavities (7) for varying a volume of the pump cavities. The system further comprises a pump drive (31) which is configured to transfer a motion to the diaphragms (13) of the pump head (1; 101; 201) for accomplishing a fluid displacement from the common inlet (3) to the common outlet (5) of the pump head (1; 101; 201; 301) as a result of said varying of the volume of the pump cavities (7).