Pressure-Balanced Drain Valve for Low Water Head Opening
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Solution Overview
Problem
Conventional drain valves require a high and variable opening force due to varying vacuum levels, necessitating a large head of water, which is impractical in space-constrained environments like aircraft lavatories.
Innovation Solution
A pressure-balanced poppet design with a hollow body and balanced pressure channels allows the valve to open consistently across different pressure conditions without relying on a large water head, using a floating poppet mechanism and optional spring support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional floating check valve design is used, then the valve can control water flow in the system, but it requires a large head of water (high opening force) to open the valve, which is not feasible in space-constrained environments
Solution Approach 1:
The patent applies the counterweight principle by introducing a hollow poppet body that traps air, creating an upward buoyant force that counteracts the downward hydrostatic pressure. This air cushion acts as a counterweight to the water pressure, enabling the valve to open with a much smaller water head (reduced from conventional high heads to just 50-150mm), thus resolving the contradiction between requiring high opening force and limited space for water head.
2Reliability
If the valve is designed to open with high hydrostatic pressure, then it can overcome varying vacuum levels on the outlet side, but it requires a large water head that consumes excessive space
Solution Approach 1:
The hollow poppet body containing trapped air provides a counterbalancing force that compensates for variations in outlet vacuum pressure. The air cushion adjusts dynamically to maintain equilibrium, allowing the valve to reliably open across a range of vacuum conditions without requiring a large water head, thus achieving both reliability and space efficiency.
Solution Approach 2:
The patent changes the physical state parameter of the poppet from solid to hollow (containing air), fundamentally altering how the valve responds to pressure differentials. This parameter change enables the valve to operate reliably under varying vacuum levels by allowing the air volume to compress or expand, adjusting the counterbalancing force dynamically without requiring large water head variations.
3Force
If a large water head is used to ensure sufficient opening force, then the valve can open reliably under high vacuum conditions, but the system becomes unsuitable for space-limited applications like aircraft lavatories
Solution Approach 1:
The air-trapping hollow poppet creates an internal counterbalancing force that eliminates the need for a large external water head. This counterweight mechanism generates sufficient opening force within a compact configuration, reducing the vertical space requirement from conventional multi-hundred-millimeter heads to just 50-150mm, making the system suitable for space-constrained aircraft applications.
Solution Approach 2:
The invention transitions from relying on vertical height (water head dimension) to generating force through internal pressure differential within the hollow poppet. This dimensional shift from external head height to internal pressure balance allows the valve to achieve necessary opening forces in a compact, space-efficient configuration.
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 consistent valve operation across varying pressures without needing a large water head, suitable for space-limited applications and adaptable for existing systems.
Implementation Method 1
The poppet (500) is hollow so as to define a pressure balancing channel (550) down the middle of the poppet (500)
Implementation Method 2
The force to open the valve is from the hydrostatic pressure of the collected water
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A drain valve assembly comprising: a valve housing (100) having an inlet port (200) and an outlet port (300) and a water collection chamber (400) between the inlet port and the outlet port, and a poppet valve (500) positioned in the water collection chamber (400) and arranged to be normally sealingly positioned across the outlet port to prevent water exiting the water collection chamber to the outlet port, the poppet valve attached to a pressure diaphragm (600) across the water collection chamber (400) such that when the pressure in the water collection chamber exceeds a predetermined opening pressure it causes the diaphragm to lift and to lift the poppet out of sealing engagement across the outlet port such that water can drain to the outlet port from the water collection chamber; wherein the poppet valve has a hollow body defining a channel (550) from a first end (501) of the poppet valve, adjacent the outlet, and a second end (502) of the poppet valve, and wherein the housing defines a vacuum cavity (110) across the second end of the channel, such that a negative pressure acting on one end of the poppet valve is balanced by a negative pressure acting in the opposite direction at the other end.