Pneumatic Pinch Valve Fail-Safe Spring Mechanism
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Solution Overview
Problem
Existing pneumatic pinch valves often fail open during air pressure loss, leading to potential tube damage and contamination risks, especially in bio-process and bio-manufacturing systems where sterility and precise control are critical.
Innovation Solution
A pneumatic pinch valve design featuring a detachable headpiece with a plunger and spring mechanism that maintains a closed position upon air pressure failure, allowing for repeated actuations without tubing damage, and can be installed without disrupting fluid flow or breaking connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pneumatic pinch valve is designed to fail open during air pressure loss, then the valve can be actuated pneumatically with simple control, but this leads to tube damage and contamination risks in bio-process systems
Solution Approach 1:
The valve is designed with reversed fail-safe behavior: instead of failing open like conventional pneumatic pinch valves, this valve fails closed when air pressure is lost. The spring mechanism automatically closes the valve upon pressure loss, preventing contamination and tube damage while maintaining simple pneumatic actuation control.
Solution Approach 2:
The spring mechanism is pre-loaded to automatically close the valve when air pressure is lost, providing preliminary protective action before contamination or damage can occur. This preemptive closing action prevents the harmful effects of tube exposure and contamination in bio-process systems.
2Reliability
If repeated pinching of flexible tubing is used to maintain closed failure mode, then sterility is maintained, but this frequently leads to tube damage and/or tube breakage
Solution Approach 1:
The plunger is designed with a rounded, curved surface instead of sharp edges. This spherical/curved geometry distributes compression forces evenly across the tubing surface, preventing stress concentration and localized damage that would lead to tube breakage during repeated actuation cycles.
Solution Approach 2:
The compression parameters are optimized by adjusting spring force, plunger surface area, and compression distance to achieve effective sealing without excessive force. This parameter optimization allows the valve to maintain closed position for sterility while using sufficient but not excessive force to avoid tubing damage.
3Ease of manufacture
If connections are broken to install the valve in place, then the valve can be properly integrated into the system, but sterility and operation performance are compromised
Solution Approach 1:
The valve is designed as a modular assembly with separable components including the valve body, headpiece, and mounting brackets. This segmentation allows the valve to be installed as a complete unit onto existing tubing without breaking connections, maintaining sterility while enabling proper system integration.
Solution Approach 2:
Mounting brackets and adapter components serve as intermediaries between the valve and the existing system tubing. These intermediary elements facilitate installation without requiring connection breaks, allowing the valve to be integrated into the system while preserving the integrity and sterility of existing fluid paths.
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 a pure closed fail mode, reduces tubing damage, and maintains sterility by keeping the system closed during pressure loss, enabling precise and safe fluid control with thousands of successful cycles without leakage or damage.
Implementation Method 1
the housing portion comprises at least one spring; The spring urges the plunger into the closed position
Implementation Method 2
a gas injected into the pneumatic chamber urges the plunger into an open position by compressing the spring and relieving compression of the tubing
Data Source
AI summary
A pneumatic pinch valve having a main body, a piston supporting a plunger, and a detachable headpiece for receiving a portion of compressible tubing between the plunger and a contoured surface of the headpiece is disclosed. A first safety cap which may restrict access to the plunger when the valve is operated and a manual override handle which may open the plunger are also provided. The pneumatic pinch valve is opened by the injection of gas through an air inlet port to a pneumatic chamber. The headpiece and plunger are configured to compress a portion of flexible tubing in a manner which reduces or eliminates damage to the tubing even after repeated open/close cycles. Further, the pinch valve may be installed onto an existing process system without disruption of fluid flow. Also disclosed is a manual version of the pinch valve.