Bioprocess Fluid Mixing with Valve-Pump Control at Low Flow Rates
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Solution Overview
Problem
Existing bioprocess fluid mixing systems have a limited operating range at low flow rates and are restricted in achieving a wide range of mixing ratios over various flow rates.
Innovation Solution
A bioprocess fluid mixing system with at least two fluid inlets, a valve arrangement, and two pumps, where pump rates and valve positions are controllable to achieve requested mixing ratios and flow rates both upstream and downstream of the pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple pumps are connected to each fluid inlet for mixing fluids, then mixing capability is achieved, but the operating range at low flow rates is limited
Solution Approach 1:
The system dynamically switches between parallel pump operation (for high flow rates) and single pump operation with valve mixing (for low flow rates). This dynamic configuration allows the system to adapt its operating mode based on the required flow rate, thereby extending the operating range while maintaining mixing capability across all flow conditions.
Solution Approach 2:
The mixing function is segmented into two independent mechanisms: (1) pump-based mixing where multiple pumps operate in parallel, and (2) valve-based mixing where a single pump supplies fluid through a valve arrangement that mixes fluids from multiple inlets. This segmentation allows the system to use the most appropriate mixing mechanism for the current operating conditions, particularly enabling low flow rate operation with a single pump.
2Ease of operation
If pumps operate at fixed flow rates, then simple control is achieved, but the volumetric mixing ratio is strongly dependent on operating flow rate
Solution Approach 1:
A valve arrangement acts as an intermediary between the pump and the mixing process. By controlling valve positions, the system can adjust the contribution of each fluid inlet independently of pump flow rates. This intermediary mechanism decouples the relationship between pump operating points and mixing ratios, allowing flexible mixing ratio adjustment while maintaining simple pump control.
Solution Approach 2:
The system changes the control parameter from pump flow rate (which has limited adjustability) to valve position (which provides continuous adjustment range). By opening or closing specific valves or adjusting their positions, the system can achieve different volumetric mixing ratios without changing pump operating parameters, thereby maintaining control simplicity while achieving mixing ratio flexibility.
3Device complexity
If each pump is dedicated to a specific fluid inlet, then simple system configuration is achieved, but the system cannot achieve wide range of mixing ratios over wide range of flow rates
Solution Approach 1:
The valve arrangement serves multiple functions: it controls fluid distribution from different inlets, adjusts mixing ratios, and enables single-pump operation at low flow rates. This multi-functional component allows a single pump to effectively serve multiple fluid inlets, achieving wide range mixing ratios and flow rates without increasing the number of pumps or complicating the overall system configuration.
Data Source
AI summary
A bioprocess fluid mixing system (3; 3′; 3″; 103; 103′), said fluid mixing system (3; 3′; 3″; 103; 103′) comprising:—at least two fluid inlets (5a, 5b, 5c, 5d, 5e), configured for providing a first fluid into the fluid mixing system through a first fluid inlet (5a) and for providing a second fluid into the fluid mixing system through a second fluid inlet (5b);—at least one valve arrangement (13a, 13b, 13c, 13a′), where a first valve arrangement (13a; 13a′) is in fluid communication with at least both the first fluid inlet (5a) and the second fluid inlet (5b);—at least two pumps (11a, 11b, 11c, 11d, 11e), where a first pump (11a) is in selective fluid communication with at least both the first and the second fluid inlets (5a, 5b) via the first valve arrangement (13a; 13a′) and a second pump (11b) is in fluid communication with at least one of the first and second fluid inlet (5b); and—a common fluid outlet (14) which is in fluid communication with both an outlet (15a) of the first pump (11a) and an outlet (15b) of the second pump (11b), wherein pump rates of the at least two pumps (11a, 11b) and valve positions in the at least one valve arrangement (13a; 13a′; 13b, 13c) are configured to be controllable by a control system (21) such that mixing of at least a first fluid from the first fluid inlet (5a) and a second fluid from the second fluid inlet (5b) can be performed to a requested mixing of the at least two fluids and to a requested combined fluid flow rate at the common fluid outlet (14).