Spray Nozzle Burst Disc for Evaporation Prevention
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Solution Overview
Problem
The existing spray devices face issues with premature evaporation and microbial contamination of pressurized liquids due to open fluid paths, which compromise the shelf life and microbial integrity of pharmaceutical spray liquids, especially in inhaler devices where a manual sealing process is inconvenient and adds complexity.
Innovation Solution
A pressure safety device with a closed burst layer is integrated upstream of the spray nozzle body, which ruptures at a threshold pressure, sealing the liquid content from the environment until first use, automatically opening the pathway for the liquid spray without user intervention, and includes a sieve device to prevent debris from obstructing the nozzle orifice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spray nozzle unit has an open fluid path for liquid delivery, then the spray function is enabled, but evaporation and microbial contamination occur compromising shelf life
Solution Approach 1:
A sealed burst disc is pre-installed in the fluid pathway upstream of the spray nozzle body before the device is put into service. This preliminary sealing action prevents evaporation and microbial contamination during storage, while the burst disc is designed to automatically rupture at a predetermined pressure threshold when the device is first activated, providing ready-for-use functionality without manual intervention
2Reliability
If a manual sealing foil is added to protect liquid content, then microbial contamination is prevented, but device complexity and manufacturing steps increase
Solution Approach 1:
The protective sealing function is extracted from the complex manual foil sealing system and replaced by a simple burst disc element integrated directly into the fluid pathway. This extracted sealing mechanism provides the same microbial protection function but with significantly reduced structural complexity and manufacturing requirements, as the burst disc is a single-component pressure-activated seal
Solution Approach 2:
The burst disc provides automatic self-activation functionality where the sealing protection is maintained during storage and then automatically removed at the moment of first use by the pressure of the liquid itself. This self-service mechanism eliminates the need for manual sealing removal or complex activation systems, reducing both device complexity and user intervention requirements
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
This solution ensures the liquid remains sealed until first use, preventing evaporation and microbial contamination, making the device convenient and fool-proof, while maintaining the microbial integrity and shelf life of the product without adding significant complexity to the manufacturing process.
Implementation Method 1
a closed burst layer that closes a fluid pathway to said spray nozzle body but ruptures once a threshold pressure is exceeded
Implementation Method 2
once the pressurized liquid is released to the spray nozzle unit for the first time, the burst layer will be exposed to the operating pressure of the device, causing the burst layer to rupture or burst as this pressure exceeds the threshold pressure
Implementation Method 3
The spray nozzle orifices that extend through the spray nozzle layer unavoidably create an open fluid path between the liquid content of the device and the environment
Implementation Method 4
this may result in inadvertent evaporation of the liquid concerned, escaping in the downstream direction
Implementation Method 5
this also allows ambient air to pass upstream while the device is not being used. This air will then enter the cavity and may finally reach the container where it will come into contact with the liquid content of the spray device
Data Source
AI summary
A spray device has a spray nozzle unit (1), wherein said spray nozzle unit (1) comprises a cavity (5) with an inlet (2) for receiving a pressurized liquid at an operating pressure and an outlet (3) for releasing a liquid spray during operation. A spray nozzle body (10) is fitted sealingly within said cavity (5), having a perforated nozzle layer (14) with at least one spray orifice (16) that extends between an upstream surface and a down stream surface thereof releasing at least one jet of said liquid spray at said downstream surface of said nozzle layer. The spray nozzle unit (1) is provided with a pressure safety device (30) upstream of said spray nozzle body (10). Said pressure safety device (30) comprises a closed burst layer (34) that closes a fluid pathway between said inlet (2) and said spray nozzle body (10) but ruptures once a threshold pressure is exceeded. Said operating pressure exceeds said threshold pressure.