An air purifier that replaces the filter with six layers of rain. A hollow shaft lifts water out of the tray, six fast-spinning serrated discs fling it into fine rain, and the air rises through all six layers — dust and odour stay in the water, the water returns to the tray, clean air leaves through the top. No filter, no consumables.
Everything that follows answers three questions —
Air: inlet slits at the bottom → radial slots in the base plate → up through six layers of rain → demister pad → fan → out through the holes in the top plate.
Water: up the hollow shaft → distributor hub → six discs → films on the windows → collecting trough → back to the tray.
Dust: rides in with the air, hits a droplet inside the rain, and returns to the tray with the water.
The path is straight: in at the very bottom, out at the very top, no U-turn in between.
Six clear Ø150 discs are stacked on one shaft at 3000 rpm. Water flows from the distributor hub onto each disc, is pushed to the rim by centrifugal force, and leaves from 240 teeth.
The rain flies 55 mm sideways on a slightly spiral path and hits the inside of the eight window panels, where it forms a film that runs down.
The windows are the collecting surface — no extra sleeve is needed.
The three front panels are clear: standing in front you see the discs spin and the rain fly.
A shallow 4.9 L tray sits inside the opaque skirt. Just above the tray rim a ring of slits in the skirt lets the air in. The strainer in the middle guards the foot of the shaft.
Rests on the tray and closes it. Radial slots let the air through upward; the trough around the edge collects the water running down the windows, and eight corner drains return it to the tray. The lower bearing sits in the centre.
One part: a Ø16 hollow shaft, a distributor hub and six serrated discs. Its foot stands in the lower bearing; its top is driven by the motor in the head. Water climbs inside the shaft, into the hub, and out onto every disc.
Eight flat panels around the rotor, standing on the base plate; the three at the front are clear. The rain from the discs lands on their inside faces and runs down as a film.
A separator plate closes the window section, then a demister pad. The rotor motor hangs in a cup above the pad; the shaft passes through the bearing in the cup.
A 140 mm fan with its own motor sits above the head. It pulls air in at the bottom, up through the rain and the demister, and pushes it out of the top.
A perforated plate closes the machine. Clean, humid air leaves straight up through the holes.
When the tube spins, the water inside is thrown against the wall and the pressure on the axis drops below atmospheric. The tray surface is still at atmospheric pressure, so water is pushed up from below. Cross vanes inside the tube force the water to rotate with it.
At the top the water enters the Ø30 distributor hub: six connected chambers, filled in one go by the ~0.9 m centrifugal head at R = 15 mm; two Ø1.5 ports per chamber feed each disc.
Six clear acrylic discs, Ø150, 15 mm apart, 240 triangular teeth on each rim. Water spreads into a ~20 µm film that accelerates outward and is split into 240 ligaments at the teeth.
Drops hit the window panels at ~19 m/s and run down as a film; the 20–60 µm secondary mist from the splash is caught by the demister pad in the head.
Air flows around a drop; a particle has mass and cannot make the turn, so it hits the drop. Finer drops and higher relative speed make this easier — a 2.5 µm particle vs a 0.2 mm drop has a single-drop collection efficiency of about 0.7.
dominant ≥ 1 µmThe particle follows the air around the drop but passes within its own radius of the surface and is held by surface tension. Independent of inertia — only size matters.
dominant 0.5–2 µmAmmonia, formaldehyde, some aldehydes, ketones and organic acids dissolve in water and are carried away. This handles odour — the real advantage of washing over a filter.
water-soluble gasesThere is a valley in the middle: 0.1–1 µm is hardest — too light to impact, too heavy to diffuse.
Finer drops make the valley shallower — that is why the drops are pushed down to 0.2 mm.
The report gives the η(d) curve itself rather than one blanket CADR number.
| Item | Value | Note |
|---|---|---|
| Envelope | 270 across flats × 409 mm | octagonal, aspect ratio 1.5 |
| Water tray | 4.9 L, 95 mm deep | shallow and wide |
| Hollow lift shaft | Ø16 × 1, 89 mm submerged | internal cross vanes, lift 81–131 mm |
| Serrated discs | 6 × Ø150 × 2 mm | 240 teeth, 15 mm pitch, rim 23.6 m/s |
| Drop size (design) | ≈ 0.2 mm | range 0.13–0.30 |
| Residence in the rain | ≈ 0.31 s | 0.44 m/s upward over 134 mm |
| Design airflow / resistance | 60 m³/h · 55–70 Pa | 140 × 38 mm high-static-pressure fan, PWM |
| Rotor motor | outrunner BLDC, 24 V, 50 W | 2500–4000 rpm, soft start, bearings at both ends |
| Demister | plate + knitted mesh + fine layer | two stages, face velocity ≥ 1 m/s |
| 2.5 µm single-pass efficiency (est.) | 25–45% | conservative 13–30%, to be measured |
| Noise (est.) | 46–57 dB(A) | mainly rain on the windows; 5 mm or laminated panels |
Water lifts itself by centrifugal self-priming · rain leaves the disc rims · dust hits the drops and stays