S1E6: How do Self-cleaning water bottles work?
Introduction
People are becoming more health conscious by moving away from sodas and preferring to drink water. This inherently increases the number of single-serve plastic bottles, moving us away from a greener earth. Many innovations and developments related to clean water have popped up in the recent few years. It’s a growing industry and in the year 2017, LARQ self-cleaning water bottles were invented to push us closer to a greener earth. Sounded like sorcery to me when I first heard of the technology from a Shark Tank episode…but here is how it works!
Note that there could be future modifications in some nuances, but the general idea has remained the same for the last couple of years.
Relevant Components
UV-C LED module
Ultraviolet light of type C (wavelength around 250 nm) emitting LED circuitry and the power source is placed underneath the bottle cap, attached to it. This is the primary component that does the cleaning process and neutralizes the germs in the water. Also, UV-C is a medically-proven technology being widely deployed in hospitals to decontaminate rooms.
Water Bottle
Of course! :D
The cap of the water bottle can be charged using a USB cable. The bottle also acts as an insulator, maintaining the water's temperature for a couple of hours. Moreover, a ring light on the bottle cap shows different statuses of the bottle (The green light is steady if it’s fully charged). A single charge will last about a month apparently.
Figure 1: Charging the bottle cap. Source: Wellrigged
Photodiode-like sensor
A photo sensor detects if the cap is fully closed and ensures the absence of light before it starts the cleaning process.
Working Mechanism
The bottle can self-clean itself every few hours. Or, you can also manually press a button to initiate the cleaning process, which would take 60 seconds in normal mode.
Ultraviolet light is used to eliminate 99.9% of bio-contaminants, viruses, and bacteria. UV disinfection technology destroys the DNA of microorganisms, leaving them dead and unable to grow further. The type of UV rays that work best to purify and clean water is UV-C (Ultraviolet rays with a wavelength of around 250 nm). This is determined after testing several times using different wavelengths of UV rays. Only UV-C can effectively kill the DNA of the pathogens. Also, the other types UV-A and UV-B are of higher wavelength and are not used for the same.
Figure 2: UV-C LED module under the cap
Ensuring water-tight bottle during cleaning
The photodiode in the water bottle generates a voltage when it’s illuminated, as it is a photo sensor. This is processed by the circuit and the cleaning process is not started when it detects light, as the bottle should be fully closed when the UVC is turned on. These rays are harmful to humans. Basically, it is assumed that the cap is not closed when the photo sensor detects any light.
Self-cleaning aspect
The UV LED setup in the cap emits UV-C rays when the button on the top is pushed. To fully clean the water, the interior of the double-walled bottle is designed to reflect the UV-C rays as the light can only travel in straight lines. Also, every few hours, the UV-C LED module automatically emits light to filter the water bottle in a few seconds. The ring light shines blue during this process.
Conclusion
Pure water and eliminating plastic is the need of the hour, and there is no denial! UV-C, a tested technology used in the medical industry and factories are being used in regular household products like water bottles. Cool tech!
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