Gate Valve Flapper Mechanism for Maintenance Without Shutdown
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Solution Overview
Problem
Gate valves fail, leading to service disruptions and potential contamination when the bonnet is removed for repair, necessitating a design that allows the valve to remain operational without shutting down water services.
Innovation Solution
A gate valve with an internal flapper valve that isolates the main body from the bonnet, enabling the bonnet to be removed for repair while maintaining fluid flow, using a biased flapper that automatically opens to allow the gate to pass through and is maintained closed by fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the bonnet is removed for repair or replacement, then the valve can be maintained, but water service shutdown occurs and customers are disrupted
Solution Approach 1:
The valve is divided into separable components (bonnet and body) with an isolating interface created by the flapper valve. This allows the bonnet to be removed independently for repair while the body remains in service with the gate closed to isolate the repair zone, enabling maintenance without water service shutdown.
2Ease of repair
If the gate valve is isolated and taken offline for repair, then the bonnet can be removed, but the integrity of the distribution system is compromised and contaminants may enter
Solution Approach 1:
The flapper valve provides preliminary isolation by closing the gate opening before the bonnet is removed. This creates a sealed barrier that prevents contaminants from entering the distribution system during bonnet removal and repair operations, addressing the contamination risk in advance.
3Device complexity
If a traditional gate valve design is used, then the structure is simple, but the valve must be completely replaced when the bonnet fails
Solution Approach 1:
The valve design segments the bonnet from the body using the flapper valve as an isolating interface. This allows the bonnet to be replaced independently without replacing the entire valve, improving ease of repair while maintaining relatively simple overall structure.
Solution Approach 2:
The bonnet can be removed, repaired or replaced, and the main body is retained and recovered for continued service. The flapper valve enables this partial replacement strategy by isolating the body from the bonnet, allowing the body to be recovered and reused without complete valve replacement.
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
Enables the gate valve to remain in service during bonnet removal and repair without disrupting fluid flow, reducing service disruptions and preventing contamination, while allowing for modular bonnet changes and maintenance.
Implementation Method 1
the flapper valve is configured and disposed such that the liquid pressure in the main body tends to urge the flapper valve towards the closed position and, once in the closed position, the pressure within the main body of the gate valve tends to maintain the flapper valve closed
Data Source
AI summary
A gate valve is provided with a flapper mechanism that is disposed in the main body of the valve and automatically works to seal and isolate the main body of the valve from a bonnet. The bonnet is isolated without any manual function or operation. When the flapper valve is in a closed position, the bonnet, gate and gate actuating mechanism can be removed from the gate valve body without isolating the gate valve. This enables the bonnet and associated components to be repaired or replaced while water or fluid under pressure continues to flow through the main body of the gate valve.