Linear-Section Pinch Valve for Uniform Low-Shear Flow Control
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Solution Overview
Problem
Conventional pinch valves and diaphragm control valves in the biopharmaceutical industry face challenges in optimizing flow control and minimizing shear forces, leading to inefficient process control and potential damage to biological molecules during fluid handling.
Innovation Solution
A pinch valve design that combines the flexibility of a pinch valve with the control performance of a diaphragm valve, featuring a valve body with a circumferential wall of elastic material and force transmitting members that change shape to maintain constant flow velocity and minimize shear forces, allowing for precise control of fluid flow without causing damage to biological materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional pinch valve is used to control fluid flow, then the valve structure is simple and flexible, but the flow control precision is insufficient and shear forces are high
Solution Approach 1:
The valve body is divided into multiple linear sections with different cross-sectional shapes (rectangular, trapezoidal, triangular) along the flow direction. This segmentation allows each section to perform a specific function: maintaining constant flow velocity in rectangular sections, gradual area reduction in trapezoidal sections to minimize turbulence, and flow direction control in triangular sections, thereby reducing shear forces while improving flow control precision
Solution Approach 2:
Different sections of the valve body are designed with different geometric properties tailored to local flow requirements. The rectangular cross-section maintains constant velocity, the trapezoidal cross-section gradually reduces area to minimize turbulence, and the triangular cross-section controls flow direction. This local optimization of geometry ensures minimal shear forces at each location while achieving precise overall flow control
2Ease of operation
If a diaphragm control valve is used to improve flow control precision, then the control performance is enhanced, but the device complexity increases and shear forces are generated
Solution Approach 1:
The patent combines the simplicity of the pinch valve structure with the flow control characteristics of diaphragm valves by integrating a constant flow velocity channel design into the pinch valve body. The linear sections with specific cross-sectional shapes provide the flow control precision typically associated with more complex valve types, while maintaining the simple pinching mechanism for actuation
Solution Approach 2:
Instead of using a diaphragm to control flow area changes (which generates shear forces), the invention inverts the approach by designing the channel geometry itself to maintain constant flow velocity through linear sections. The control is achieved through the fixed geometric properties of the linear sections rather than dynamic diaphragm deformation, eliminating the need for complex diaphragm mechanisms
3Ease of operation
If the flow channel cross-sectional area varies along the valve body, then flow control is possible, but the flow velocity becomes non-uniform and shear forces increase
Solution Approach 1:
The flow channel is segmented into distinct linear sections with constant cross-sectional areas along each section's length. The rectangular section maintains constant area for uniform velocity, the trapezoidal section provides controlled area transition zones, and the triangular section manages flow direction changes. This segmentation ensures that velocity remains uniform within each section while enabling overall flow control through the valve
Solution Approach 2:
The cross-sectional area parameter is changed in a controlled manner through the sequence of linear sections. The rectangular section maintains constant area (S = a × b), the trapezoidal section gradually changes area through its inclined sides, and the triangular section reduces area to a point. This parameter progression allows flow control while maintaining velocity uniformity within each linear section
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 pinch valve achieves optimized process control with reduced shear forces, ensuring gentle transport of liquids and maintaining constant flow velocity throughout the valve body, thereby preventing damage to biological cells and improving fluid handling efficiency.
Implementation Method 1
The circumferential wall consists of an elastic or yieldable material. If a compressive or tensile force acts on a force transmitting member, then this force transmitting member is moveable perpendicularly to the flow direction of the flow channel.
Implementation Method 2
The circumferential wall of the valve body in cross section encloses an area of the flow channel that is at least essentially constant along the entire valve body. As a result, the mean flow velocity in the flow channel is at least essentially uniform or constant at all positions along the valve body.
Data Source
AI summary
The invention relates to a pinch valve comprising a valve element (4) with precisely one flow channel (20) that is surrounded by a circumferential wall (21) and has an inlet opening (24), which is designed for connecting a connection member (2) or which adjoins a connection element (2a), at a first end and an outlet opening (25), which is designed for connecting a connection member (2) or adjoins a connection element (2a), at a second end. The valve element (4) additionally has a pair of force transmitting elements (19, 19′) or a force transmitting element (19) and a fixing element (26) which are connected to the circumferential wall (21) in a central closing region (18) that is arranged between the inlet opening and the outlet opening. The force transmitting elements (19, 19′) or the force transmitting element (19) and the fixing element (26) are arranged at least substantially perpendicularly to the flow direction of the flow channel (20). The circumferential wall (21) consists of an elastic material such that the force transmitting elements (19, 19′), or the force transmitting element (19) and the fixing element (26), can be moved towards each other under the effect of a pressure or tensile force perpendicularly to the flow direction of the flow channel (20). In the absence of a pressure or tensile force acting on a force transmitting element (19, 19′), the circumferential wall (21) has a cross-section which differs from a circle in the central closing region (18). In the cross-section, the circumferential wall (21) surrounds a flow channel (20) surface area which is constant at least substantially over the entire valve element (4). Thus, the average flow speed is at least substantially uniform at all positions along the valve element (4).