Shut-off Valve Base Flange Ring Nut Corrosion
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Solution Overview
Problem
Existing shut-off valves for fire extinguishers, particularly water extinguishers with corrosive agents, face corrosion issues due to the exposure of threaded parts to the extinguishing agent, and current solutions are either costly or not economically advantageous, lacking automation in assembly.
Innovation Solution
A shut-off valve design featuring a base flange fixed to a ring nut with screws, where the ring nut has a step not protruding inside the tank, allowing continuous coating and using commercial steel screws for cost-effectiveness and automated assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic protection treatments such as nickel-plating or protective treatments such as cataphoresis are used on the valve-body, then corrosion resistance is improved, but the threaded part is strongly compromised or totally eliminated when the valve is screwed to the tank, exposing the bare threaded part to the corrosive agent
Solution Approach 1:
The patent introduces a ring nut as an intermediary component between the tank and the valve body. The ring nut has a female thread that engages with the male thread of the valve body, while the tank has a male thread that engages with the female thread of the ring nut. This intermediary allows the protective coating on the valve body to remain intact while still enabling threaded assembly, as the ring nut serves as the actual threaded interface with the tank.
Solution Approach 2:
The patent divides the connection system into separate components: the tank with its own threading, the ring nut with complementary threading and protective coating, and the valve body with protective coating. This segmentation allows each component to be optimized independently - the tank provides structural support, the ring nut provides the threaded interface with corrosion protection, and the valve body maintains its protective coating while being detachable.
2Reliability
If the ring nut is welded to the tank with male thread and external turn lock on valve-body, then corrosion resistance is improved, but the assembly cannot be automated and requires manual screwing with a wrench
Solution Approach 1:
Instead of having the valve body with an external turn lock that requires manual operation, the patent inverts the approach by providing the ring nut with the female thread and the tank with the male thread. This allows the valve body to be screwed onto the ring nut from the outside, enabling automated assembly processes while maintaining corrosion resistance through the protective coating on both the valve body and ring nut.
3Ease of operation
If the ring nut protrusion inside the container is used for valve fixing, then valve positioning is achieved, but the continuous coating of the internal surface with protective layer is not allowed
Solution Approach 1:
The ring nut serves as an intermediary structure that is welded to the tank mouth but does not protrude inside the container. The valve body is then attached to the ring nut's external female thread. This arrangement allows the ring nut to provide positioning and fixing functionality while maintaining the continuous protective coating on the internal surface of the container, as the ring nut's threading interface is located outside the container interior.
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
Shut-off valve, particularly for portable water fire extinguishers, or in any case containing corrosive extinguishing substances, comprising a valve-body (2) that can be fixed to a ring nut (20) welded to the mouth (102) of an upper dome (101) of a tank (100) containing the extinguishing substance, in which said valve-body (2) has a base flange (23) that can be fixed by means of screws (24) to said ring nut (20).