Man, that's really dangerous. XD I like it.

Being intended for public release, this apparatus will need to meet all the electric security requirements :
- the cabin metal grid is enclosed inside two 5mm-thick sheets of plexiglass to ensure electrical isolation and avoid accidental discharge.
- the high-voltage circuit linked to the central handle is physically separated from the six other powering the electrostatic fans and limited by construction to a maximum current of 10 µA.
One funny thing is that, being a electric device operating without water nearby, the EPL shower should not have to meet the rather strict requirements for equipments in classic wet bathrooms.

I'm assuming people would want to have this in their bathrooms, though. That's usually where cleaning takes place and they'll want to be near a sink and a toilet.

i bet that tingles.... *blink all over!....

would you be required to touch a discharge plate afterwords? as it is i can create enough static to shock everybody that comes by... ^=^ (good fun that)


anyway nice work!

I though of the inner door handle to have this role of discharge plate : the bolt linked to it acts as a contact with the door panel metal grid connected to the ground, but the discharge only occur when the handle is fully rotated. Thus no big spark should occur as the hand is already in contact with the metal at this point.

Good thinking. That would work.

good thinking...

nothing like getting a shock every time you step out of the shower... or in my current case the car.... o.0

Very clever! When I was charged by a 300 KV Van deGraff my hair sure did stand up! I like your idea of the ultrasonics, too. 500 microamps is quite safe and too little to feel. Just ground the door handle through a 100 megohm resistor and the shower user won't feel any shock when exiting the chamber, but will be discharged in a fraction of a second.

Thanks for the advice ! But I'm not sure to build such a machine for real, except perhaps a horizontal version for four-legged pets.
In fact, I'm wondering now if the ultrasonics generator is really necessary : perhaps adding a low-voltage high-frequency component to the continuous high-voltage potential will make the fur vibrate as well because of the oscillatory electrical field. It would suppress the only mechanical element of the system.

That might work, but the ultrasonics can be quite reliable. Piezoelectric ultrasonic transducers are very reliable. For very high powers, ultrasonic whistles work very well. I have one about the size of my thumb that emits 1.5KW acoustic at 35 KHz at 45 PSI air pressure. These devices are used to break foam in chemical reactors. When I put a cotton ball next to it, the ball will smoke! A higher frequency such as your 70 KHz would be needed for small animals like cats and dogs.

sure it gets the dirt off , but what about sanitation (germs ect6ra) and and smells?

- Bacteria need a warm and humid environment to develop themselves, but the air driven into this kind of shower is dry and not heated so the filters shouldn't be subject to the development of mould. Concerning the body sanitization, waterless soaps could be used to reduce the skin bacterial fauna then the dry residues removed from the fur with a soft-teeth comb.
- Body smell is mainly due to the degradation of the sweat in excess (composition equivalent to very diluted urine) by commensal bacteria living on the skin. If we assume that furries would have the same sweat glands as humans, the puffing of the fur thanks to the electric field would allow the airflow to go through the fur and evacuate the sweat in excess by forced evaporation.

thanks :)

comme les canidés ont une oreille capable d'entendre des sons bien au-delà de la limite d'audition humaine, je pense qu'il faudrait remonter la fréquence à laquelle tu fais vibrer la fourrure au delà de 80kHz

Il est vrai que la fréquence de vibration doit être adaptée à l'espèce utilisatrice, car les ondes de surface générées par les éléments piézoélectriques peuvent être captées par l'oreille interne via la conduction acoustique osseuse. Mais le rendement de conversion électrique/mécanique des éléments vibrants a de bonnes chances de décroitre avec la fréquence d'utilisation, donc il faudra trouver un compromis.

Interesting theory, but it has several practical issues:

- The unidirectional air flow would give a highly non-uniform cleaning. The armpits, crotch, chin, ear insides and under the tail would not receive a good cleaning
- It would have serious problems reaching all the way to the skin of dense fur coats
- Being constantly treated with dry air would dehidrate the fur, requiring the fur to take regular wet baths to rehidrate it anyway
- If the fur can hear at the 50Khz-70Khz range it would be more of a torture chamber than a cleaning device
- Dirt and bacteria wouldn't fall straight through. When a bacteria gets loose from the airflow/vibration it would end up getting caught again by another strand of fur, making it a very long bath, till everything has fallen all the way through.
- Sweat and other body fluids are rather sticky, and the surface of the fur and the skin are rather rough, making it really difficult to remove dirt mechanically.
- Tougher parasites like louse, ticks and mites hold themselves really tightly to the host. Louse eggs are GLUED to the fur. I don't see how would an air flow remove them in any way.
- While the static electricity would make the fur puff, the downward airflow would tend to push the fur back down, possibly even dissipate the static electricity.
- It doesn't look a lot more effective than just blowing oneself with a hairdryer

You also need to consider animal fur is not like human hair. More often that not, it's heavier and harder, meaning you need a lot of static electricity to puff any kind of fur.

Well, I don't own any domestic animal so my experience with washing fur is limited, but I know that their fur takes a lot time to dry. This concept was just an attempt to check the feasibility of water-less fur cleaning methods and isn't a definitive design.

One alternative of the piezoelectric transducers would be the Fog Gun invented by Buckminster Fuller, as it uses a very low amount of soapy water and the high pressure can help remove dirt. In this configuration the system would be electro-mechanical instead of purely electrostatic, with electric motors driving both a centrifugal fan placed at the base of the shower (and protected by a solid non-conductive grid) and a small air compressor, the Fog Gun's grip being put at the high voltage needed for fur puffing while the central platform is isolated from the ground.

By the way, I already answered to some of your objections with other commentators' remarks. For example, the cleaning vibrations would not be emitted as ultrasounds but as mechanical surface waves travelling on the skin and fur. Since the only way to ear mechanical waves would be from bone conduction and that the skin penetration depth decreases with frequency, higher frequencies means less risk of involuntary hearing.

As for the electrostatic energy needed for the puffing, it can be calculated with the right data :
- The electric charge Q accumulated by the body thanks to the electrostatic generator is measured in coulombs and equal to I*s (steady current in amperes * time in seconds) and F*V (effective capacitance of the body-cage capacitor in farads * potential difference in volts)
- The formal definition of the ampere is "the constant current which will produce an attractive force of 2 × 10–7 newtons per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum". So we can use the Ampere's force law F/L = 2*ka*I²/d (ka=10^-7 N/A², d the distance between the conductors in meters) to determine the repulsion between two consecutive hairs.
- To make fur stand on its end with static electricity, the maximal amount of force needed would be to overcome the weight of individual hair. It means that the equation lm*L*g = F/L => lm*g = F must be respected (lm is the lineal mass of one hair in grammes per meter, g the gravity constant is 9.81 grammes per newton)
- Knowing the potential difference (30 kV) and maximum current (1-10 µA) delivered by the electrostatic generator, as well as the separation between individual hairs (0.01-1 mm) and corresponding lineal mass (to be found) it should be easy to determine the electrical energy needed.