Tubular Plastic Hydrant Pressure Relief Valve Design
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Solution Overview
Problem
Freezeless wall hydrants can burst due to pressure buildup from trapped water freezing, leading to potential contamination of the water supply when pressure relief valves fail, and conventional designs face issues with backflow and corrosion.
Innovation Solution
A valve assembly with an outer and inner tubular member, an annular seal, and a control mechanism that allows for pressure relief through a second port to prevent pipe rupture and contamination, featuring a telescoping seal that advances to relieve pressure even when the handle is fully closed, and redundant pressure relief mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a pressure relief valve is used to relieve pressure from freezing water, then pipe rupture is prevented, but contaminated water can be forced back into the supply line causing cross contamination
Solution Approach 1:
The patent introduces a mediator device (the valve assembly with telescoping seal and relief port) between the hydrant pipe and the frozen water section. This intermediary mechanism relieves pressure by allowing controlled expansion space for freezing water through the relief port, rather than forcing water back through a traditional pressure relief valve into the supply line, thus preventing cross-contamination while still protecting the pipe from rupture
Solution Approach 2:
The valve assembly segments the hydrant system into controlled zones: the inner member with telescoping seal creates a isolated chamber that can expand independently when water freezes, while the relief port provides a dedicated pressure relief path that doesn't connect to the potable water supply, separating the pressure relief function from the water supply function to prevent contamination
2Ease of operation
If the closure means is fully advanced by the handle to close the valve, then water flow is stopped, but pressure cannot be relieved from expanding ice formation
Solution Approach 1:
The patent makes the closure means dynamic by allowing it to advance beyond the normal closed position. The telescoping seal on the inner member can continue to move forward even after the handle is fully tightened, providing continued pressure relief capability. This dynamic extension allows the system to adapt to freezing conditions by creating additional expansion space and opening the relief port, while maintaining the simple single-handle operation for normal valve control
3Stress or pressure
If a telescoping seal is used to relieve pressure by advancing beyond closure position, then pressure relief is achieved, but the mechanism complexity increases
Solution Approach 1:
The patent merges multiple functions into the closure means: it serves as both the normal valve closing mechanism and the pressure relief mechanism. The telescoping seal is integrated into the existing inner member structure, and the relief port is built into the valve body, eliminating the need for separate pressure relief valves or complex additional mechanisms. The single handle operates both functions through the unified closure means design
Solution Approach 2:
The telescoping seal mechanism is self-activating based on pressure conditions. When water freezes and pressure builds up, the force from the expanding ice automatically pushes the telescoping seal forward beyond the closed position, opening the relief port without requiring external control. The system uses the problem itself (pressure buildup) to trigger the solution (pressure relief), reducing the need for complex control systems
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
Prevents pipe rupture and contamination by effectively relieving pressure from freezing water, ensuring the hydrant can drain residual water and maintain water quality by preventing backflow and corrosion.
Implementation Method 1
closure means defining an annular seal extending about an axis defined by said closure means, there being an axially elongated bore defined by the outer member, and into which said seal has sliding sealing fit as the closure is advanced
Implementation Method 2
the seal will continue to advance after closure is fully advanced by handle limit... pressure relief through a second port to prevent pipe rupture and contamination
Implementation Method 3
Water trapped in the hydrant will freeze when temperatures drop below 32 degrees Fahrenheit. As the water freezes, it expands.
Implementation Method 4
As the water freezes, it expands. The hydraulic action of the freezing water expanding increases pressure on the liquid portion of the water remaining in the hydrant pipe
Data Source
AI summary
In a hydrant assembly, the combination comprising an outer tubular member having a first flow port; an inner tubular member having a closure thereon to close the port in relative axially advanced position of the closure, and to open the port in relative axially retracted position of the closure that allows fluid flow through the port to an outlet, control means to control relative movement of the inner and outer members. The closure means may include a bullet, an O-ring or the like carried by said bullet, the bullet telescopically carried by said inner member. A bore carried by the outer tubular member is in sliding sealing relationship to said O-ring. Once hydrant is closed (off position) the bullet will continue to advance into the bore as pressure in the outer tubular member increases when residual water freezes. Because of advancement of the bullet, pressure in the outer tubular member will never exceed supply line pressure thus preventing damage to the outer tubular member. A second port may be located sidewardly of the outer tubular member to pass fluid in relatively advanced position of the closure to relieve fluid pressure in space formed between the inner and outer members, the inner member being elongated and extending lengthwise in the outer tubular member. Since the pressure in the outer tubular member never exceeds the supply pressure, the outer tubular member can be made of plastic to reduce costs.