Freeze Tolerant Ball Valve Sacrificial End Cap Design
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Solution Overview
Problem
Ball valves are vulnerable to damage from freezing water due to trapped moisture, with existing solutions like drainage ports often being ineffective due to user neglect or unexpected freezing events, leading to consistent damage on the valve body.
Innovation Solution
A freeze-tolerant ball valve design featuring a concave plug with scored areas and a thick-walled section that directs water expansion towards a sacrificial end cap, which ruptures under pressure, protecting the rest of the valve from damage, and allowing for easy replacement of the end cap without replacing the entire valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drainage ports are provided to remove trapped water, then freezing damage is prevented, but users often forget to open the drainage port before freezing occurs, making the solution ineffective
Solution Approach 1:
The valve automatically directs freezing water toward the sacrificial end cap through its internal geometry, eliminating the need for user intervention. The design self-activates during freezing events by utilizing the natural expansion direction of water to rupture the designated sacrificial component.
Solution Approach 2:
The valve is pre-configured with asymmetric wall thicknesses and internal geometry that predeterminedly guide freezing water toward the sacrificial end cap before freezing occurs. The structural design is prepared in advance to channel expansion forces to the intended failure point.
2Strength
If the entire valve body is made thick-walled to prevent freezing damage, then strength is improved, but manufacturing complexity and material usage increase
Solution Approach 1:
The valve body features asymmetric wall thicknesses with the first sidewall being thick-walled for strength while the second sidewall with the sacrificial end cap is thin-walled. This localized differentiation provides strength where needed while creating a designated weak point for controlled failure during freezing events.
Solution Approach 2:
The sacrificial end cap is designed as a replaceable, lower-cost component with thinner walls that is intended to fail during freezing events. Rather than protecting the entire valve body uniformly, the design sacrifices this specific component to protect the more valuable main valve body and spherical gate.
3Reliability
If drainage ports are exposed to the side opening, then water can be drained, but the side outlet is likely to be plugged at the time of freezing, making the solution ineffective
Solution Approach 1:
The drainage function is extracted from the main valve body and integrated into the replaceable sacrificial end cap. This separates the drainage function from the permanent valve structure, allowing the end cap to be removed and replaced if it becomes plugged or fails, without affecting the main valve body.
Solution Approach 2:
The sacrificial end cap is designed as a dynamic, replaceable component rather than a fixed permanent part. Its removability allows the system to adapt after failure by replacing the capped component, restoring drainage functionality without replacing the entire valve.
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 solution effectively redirects and manages water expansion, preventing damage to the valve body by allowing the sacrificial end cap to rupture instead of the main valve components, and enables quick and cost-effective maintenance by allowing the concave cap to be readily replaced.
Implementation Method 1
the scored areas of the plug act create a sacrificial surface that gives away under the pressure from water expansion due to freezing
Data Source
AI summary
A freeze tolerant ball valve for controlling the direction of expansion of freezing water within the ball valve is disclosed. The valve includes valve body inlet and the valve body outlet, and a spherical-shaped gate that has an axial fluid passage that extends through the spherical-shaped gate. The spherical-shaped gate can be rotated to block fluid communication between the valve body inlet and the valve body outlet. The valve body also has a first sidewall that is of a first sidewall thickness, and a sidewall having a boss that supports a concave cap that has a bottom wall that is of a bottom wall thickness, the bottom wall thickness being substantially thinner than the sidewall thickness. The cooperation of the passage through the spherical-shaped gate, the first sidewall with its first sidewall thickness positioned opposite to the bottom wall of the concave cap results in a valve that directs the effects of freezing on to the concave cap, which would fail first in the event of freezing. The cap can be easily and quickly replaced in the event of failure.