Parallel Capacitor safety at 10 micron plate spacing

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    Electric field
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Discussion Overview

The discussion revolves around the safety and feasibility of using a parallel capacitor with very small plate spacing (10 microns) to generate a high electric field (500 kV/m) for the purpose of inactivating airborne viruses while maintaining airflow. Participants explore the implications of voltage, dielectric materials, and the potential health hazards associated with such a setup.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether a 5V charge can realistically create an electric field of 500 kV/m with 10 micron spacing, and whether this setup poses a lethal risk.
  • There is discussion about the dielectric material required between the plates to prevent breakdown, with references to dielectric breakdown and the Paschen Curve.
  • One participant suggests that increasing the plate separation could raise the voltage, thus changing the circuit's classification under regulations.
  • Concerns are raised about maintaining the electric field under airflow and whether air as a dielectric must be still or sterile.
  • Participants propose the use of mesh capacitors and discuss the implications of using solid versus gas dielectrics in relation to airflow and contamination risks.
  • There are suggestions about using charged plates to trap airborne particles and viruses, with considerations of the required voltages for effective operation.
  • Some participants express skepticism about health hazards at low voltages, while others note that capacitors can store high amounts of electricity, raising safety concerns.
  • Discussion includes the potential effectiveness of AC voltage in treating viruses compared to DC voltage and the need for pre-filters to manage dust accumulation.

Areas of Agreement / Disagreement

Participants express varying opinions on the safety of low voltage setups, the effectiveness of different dielectric materials, and the feasibility of using electric fields for virus inactivation. There is no consensus on the best approach or the safety implications of the proposed designs.

Contextual Notes

Participants highlight limitations related to the cleanliness of air, the potential for dust accumulation on capacitor plates, and the unresolved nature of how electric fields interact with airborne particles. The discussion also reflects uncertainty about the practical implementation of the proposed concepts.

Who May Find This Useful

This discussion may be of interest to those exploring innovative air purification methods, the application of electric fields in virus inactivation, and the technical challenges associated with capacitor design in low-voltage environments.

  • #31
The characteristics on an arc are similar to an SCR. Trigger voltage, conduction resistance(on), insulation resistance (off) holding current (DC) and zero-crossing extinguish current.

With a steady voltage above the holding current, you have a tiny plasma corona generator.
With a steady voltage and current limited below holding current, you have a tiny random relaxation oscillator or a flea zapper.
A resonant oscillator is slow to start depending 0.35/BW which depends on Q=fo/BW.
Without a theory of operation or a design spec, you have little to go on.
 
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  • #32
sophiecentaur said:
This is very relevant to the realisation of a practical system. Fact is that there is no new technology in the OP's idea and I'd suggest that dealing with viruses in this way would be standard practice (by now) if it were feasible. I know that argument may be questionable and " it hasn't been done yet" can appear to be lazy reasoning. This is essentially a practical problem and the urgency for finding methods for control of airborne viruses must have stimulated loads of attempts up-scaling from a small lab experiment to a system for treating many litres per minute.

Afaics, the paper that the OP quotes is based on a theoretical molecular model and I could find no mention of how to achieve the sort of fields involved. No engineering at all??? Perhaps the title of the thread should have been "How to obtain a field of tens of kV/m across a parallel plate air filter" Also there seems to be a suggestion in the paper that the exposure time to damage the virus would only need to be 1 microsecond so low frequency RF would be very suitable (and handleable).


The thread has had to morph into a teaching / learning exercise for the OP and caused distractions from the main Engineering Considerations . Many of the above posts seem not to have appreciated the OP's naive view of the subject. The mentions of vacuum capacitors and dielectrics may have produced more confusion than clarification, I'm afraid. Great for a chat and perfectly correct but not what the OP needed. (The 'I' grade of the question was a bit misleading, perhaps.)

There are some initial assumptions about the basic idea that instantly knock it on the head (see the above para). Why is 5V somehow a necessary working voltage?; spacing would need to be microscopic which is just not practical. Plenty of safe, portable equipment has many kV circuitry inside it so why the 5V restriction? (Easy to obtain 5V power source and to work with, perhaps.) We can conclude that there has to be much more than 5V involved - but so what? The construction of the old air spaced variable tuning capacitors is the way it is for good reasons but those are not subjected to a high through-flow of air.
@sophiecentaur thank you for your comments. 5v / 9v is admittedly based on assumed limitations for powering lightweight wearable devices. And being able to run this with a disconnected battery using plate separation sounded like a very attractive effect to power ratio. I'm unaware of multi kV battery powered equipment (wearable) .... what size equipment/battery packs are we talking?

Also, can't deny the point that the paper is simulated, (therefore not yet proven real world)

And as importantly, the premise here is that an EF takes over much of the the anti viral work of HEPA thus allowing a downgrade to lower filtration efficiency like MERV13 or MERV8 and thus an upgrade in flow rate. (Assuming that capacitors could be spaced much better than HEPA fibres). This improves overall efficiency and may handle the virus in one air pass. 100% efficiency with fast flow rate. There's an oversight here on my part. All of this would assume the next pandemic is caused by a virus. The previously quoted paper notes that virus spike proteins are unusually susceptible to moderate EFs. If the next pandemic was caused by airborne bacteria, the filters that remove bacteria have been downgraded and replaced by an EF which is probably ineffective against bacteria.
 
Last edited:
  • #33
Saint Elmo said:
I'm unaware of multi kV battery powered equipment (wearable) .... what size equipment/battery packs are we talking?
You don't need a 100kV battery; that would not be convenient or cheap.12V batteries are good for starters and the circuitry would be low voltage until the output. A resonant transformer would give you kV only where needed.
Saint Elmo said:
This improves overall efficiency and may handle the virus in one air pass. 100% efficiency with fast flow rate.
At this point in the (maybe) development of an idea like this, what's needed is small scale attempts to realise in practical terms what that theory suggests. What you're suggesting is that we could bypass the normal chain of development of an idea and arrive at some personal protection device. Any such development needs to be done by people with detailed EM knowledge. I think you have to take that on board.
Saint Elmo said:
was going to get round to it eventually but did want to avoid egg on face if a non runner from the get go or if a health hazard.
you said it. (Not a health hazard if done properly, though).

There's also the point that you would need a virus-safe working environment to test this stuff. (££££)
 
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