Liquid Dispensing Device Pre-Compression Outlet Valve
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Solution Overview
Problem
Conventional liquid dispensing devices, such as aerosol sprayers and pre-compression sprayers, face issues with non-uniform droplet sizes, environmental hazards, and the need for continuous user activation, while pre-compression sprayers struggle with priming due to high outlet valve pressures and hysteresis in outlet valves.
Innovation Solution
A liquid dispensing device with a piston chamber, nozzle, and separate prime valve for efficient priming, along with a buffering system to control output pressure and droplet size, and a dome valve design to minimize hysteresis and enable continuous spraying without user activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-compression outlet valve is used to control minimum output pressure, then droplet size is controlled, but hysteresis in the valve causes inefficient priming and air removal
Solution Approach 1:
The patent divides the valve system into two separate valves: a pre-compression outlet valve for controlling minimum output pressure and droplet size, and a separate prime valve specifically for priming operations. This segmentation allows each valve to be optimized for its specific function, with the prime valve having lower opening pressure to efficiently remove air during priming without being constrained by the higher pressure requirements of the outlet valve for droplet control.
Solution Approach 2:
The prime valve acts as an intermediary component that facilitates the priming process by providing a dedicated pathway for air removal. It mediates between the high-pressure requirements of the outlet valve and the low-pressure needs of efficient priming, allowing air to be evacuated through the prime valve at lower pressures while the outlet valve maintains proper pressure for droplet formation.
2Ease of operation
If aerosol propellant is used to maintain continuous spray, then spraying continues without user activation, but environmental hazards and packaging complexity increase
Solution Approach 1:
The patent replaces the chemical/aerosol-based pressure maintenance system with a mechanical pump-based system. Instead of using aerosol propellants to maintain pressure, a pump mechanism mechanically pressurizes the liquid reservoir, enabling continuous spray capability without the environmental hazards associated with propellant chemicals and reducing packaging complexity.
3Ease of operation
If motorized pump is used for continuous spray in floor cleaners, then spraying continues without user activation, but device robustness and battery life are compromised
Solution Approach 1:
The patent replaces complex motorized pump systems with a simpler mechanical pump mechanism that can be manually actuated. This substitution maintains continuous spray capability while improving device robustness and reliability by eliminating motors and complex electrical systems that require battery power and are prone to failure.
Solution Approach 2:
The patent employs periodic manual actuation of the pump mechanism to maintain continuous spray. Instead of requiring constant motor operation, the user periodically activates the pump, which then maintains pressure and enables continuous spraying between activations. This periodic action reduces wear on mechanical components and eliminates the need for continuous electrical power.
4Ease of operation
If conventional sprayer starts dispensing at low pressure, then ease of operation is improved, but droplet size becomes non-uniform due to pressure variation during stroke
Solution Approach 1:
The patent implements pre-compression of the liquid reservoir before dispensing begins. The pump mechanism pre-pressurizes the liquid to a controlled minimum pressure, ensuring that when dispensing starts, the pressure is already optimized for uniform droplet formation. This preliminary action eliminates the pressure variation that occurs in conventional sprayers during the stroke, maintaining consistent droplet size throughout operation.
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 device achieves precise control over output pressure and droplet size, allowing for continuous spraying and efficient priming, reducing environmental impact and user dependency, while minimizing hysteresis in the outlet valve for improved performance.
Implementation Method 1
a piston that is moveable within the piston chamber to pressurise a liquid to be dispensed
Implementation Method 2
an outlet valve having a defined minimum opening pressure arranged between the piston chamber and the nozzle
Implementation Method 3
dome valve design to minimize hysteresis and enable continuous spraying without user activation
Data Source
Figure 1A~1C
Figure 2
Figure 3~9
AI summary
The invention relates to a liquid dispensing device comprising: a piston chamber; a piston that is moveable within the piston chamber to pressurise a liquid to be dispensed; a nozzle with a defined throughput for dispensing the liquid; an outlet valve having a defined minimum opening pressure arranged between the piston chamber and the nozzle; and a prime valve for priming the device. The prime valve may be mechanically operable and may be arranged on or in the piston. The liquid dispensing device may further comprise an operating member, which may protrude from an end wall of the piston chamber and which may be arranged to move the prime valve from a closed position to an open position when the moveable piston is near or at an end of its stroke. The outlet valve may be configured to minimize a difference between its opening pressure and its closing pressure. It may comprise a dome and the dome may have a stiffness which varies in radial direction.