Pneumatic Safety Valve Locking With Trapped-Air Venting
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Solution Overview
Problem
Existing air-operated valves lack a reliable mechanism to prevent inadvertent changes in status, particularly in hazardous environments, where they must remain locked in a desired position despite mechanical vibrations or unauthorized manipulation, and fail to address issues like trapped air or incomplete air flow causing unintended valve operation.
Innovation Solution
A normally closed valve with an internal safety mechanism that allows simultaneous mechanical locking, blocking air supply, and venting, enabling a single manual operation to maintain the valve in a desired state, using a control shaft, threaded stopper, and pneumatic disable mechanism to align ducts for controlled air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a padlock or mechanical locking mechanism is used to lock the valve handle in fully open or closed positions, then the valve is protected against tampering and unauthorized manipulation, but the valve cannot be serviced or manually manipulated when required, and the locking does not prevent malfunction due to trapped air or incomplete air flow
Solution Approach 1:
The locking mechanism is segmented into multiple functional components: a control shaft with ducts, a threaded stopper with air supply connection, and a pneumatic disable mechanism. These segments work independently yet cooperatively to achieve locking, air blocking, and venting functions separately, allowing maintenance access while maintaining security.
Solution Approach 2:
Pressurized air acts as an intermediary medium to transmit the operator's manual input through the control shaft and threaded stopper to the pneumatic disable mechanism. This intermediary enables remote control of the locking mechanism without direct mechanical contact, facilitating both secure locking and easy servicing.
2Reliability
If the valve is designed to be air-to-open (ATO) to fail closed (FC) for safety, then the valve closes automatically when air supply fails, but trapped air or failure to vent air completely can keep the valve open when intended to be closed
Solution Approach 1:
The threaded stopper is pre-configured with a dedicated air supply connection and the control shaft contains pre-positioned ducts that lead to the pneumatic disable mechanism. This preliminary arrangement ensures that when the locking mechanism is activated, air is automatically blocked from reaching trapped pockets and can be vented through predetermined paths, simplifying the overall venting process.
Solution Approach 2:
The invention uses pneumatic principles to control the locking mechanism. Pressurized air is supplied through the threaded stopper to actuate the pneumatic disable mechanism, which in turn controls the locking action. This pneumatic system provides reliable, remote-controlled operation with inherent fail-safe characteristics.
3Ease of operation
If a single manual manipulation is used to simultaneously lock the valve, block air supply, and vent trapped air, then the valve operation is simplified and enhanced safety is achieved, but the mechanism requires precise coordination of multiple functions in one action
Solution Approach 1:
The control shaft and threaded stopper are merged into a integrated assembly where the control shaft rotates within the threaded stopper. This merging combines the air blocking function (threaded stopper) and the venting control function (control shaft with ducts) into a single coordinated mechanism that responds to one manual input.
Solution Approach 2:
The control shaft serves multiple functions: it rotates to control the alignment of ducts for venting, it transmits rotational motion to the pneumatic disable mechanism for locking, and it provides a manual interface for operation. This multi-functionality allows a single component to coordinate multiple safety functions simultaneously.
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
Ensures the valve remains in a desired state by preventing inadvertent opening or closing, even with minor manipulations, providing enhanced safety and reliability in hazardous environments.
Implementation Method 1
The control shaft and the threaded stopper may be urged together by resilient means
Implementation Method 2
there is a flow of pressurized air via pneumatic means through the internal safety mechanism, causing the diaphragm to transition to open state
Data Source
Figure 1
Figure 2~3
Figure 4a
AI summary
A normally closed valve comprising: a seat that has a fluid inlet and a fluid outlet; a diaphragm, an external handle and an internal safety mechanism operationally coupled to the external handle and the diaphragm. The valve allows forcing the handle in a first direction, thereby moving the internal safety mechanism through at least a first and subsequently a second stage. During the first stage: the diaphragm is pressed onto the seat, flow of pressurized air through the internal safety mechanism is blocked, and air pent in the valve is vented, causing the valve to be and remain in a closed state. During the second stage: flow of pressurized air through the internal safety mechanism is allowed, the pressurized air after passing therethrough, acting against the pressing of the diaphragm onto the seat;, and a venting of air is reduced, causing the valve to be and remain in an open state.