Short answer: size the tank to the batch, not the bench. A showroom cleaning customer pieces one at a time is well served by 2 to 3 litres; a finishing room cleaning dozens of pieces per cycle needs 10 litres; a casting or polishing house running more than one shift needs 15 to 30. Frequency matters as much as size: 40 kHz for finished jewellery and mounted stones, 28 kHz for casting plaster and heavy compound, or a dual-frequency unit for both.
Tank size by what you clean
| Capacity | Suits | Typical load |
|---|---|---|
| 0.6 L / 0.75 L | Single bench, designer studio, gem lab | Loose stones and single pieces |
| 1.3 L / 2 L | Small showroom counter, gemmologist's workstation | A few rings or a chain |
| 2.85 L / 3 L | The usual independent showroom choice | A tray of rings, chains or earrings in one load |
| 4.5 L / 6 L | Multi-counter showrooms, repair shops, small manufacturing units | Bangles, statement necklaces, bridal sets |
| 6.5 L / 9.5 L / 10 L | Factory finishing rooms, casting houses after investment | Dozens of pieces per cycle |
| 15 L | Casting and polishing houses on more than one shift | Batch after batch |
| 20 L / 30 L | Large manufacturers, watch factories, dental labs, metal-recovery operations | Multi-transducer arrays keep cavitation even across the tank |
A tank that forces two runs per batch costs more in operator handling, over a year, than the larger tank costs to buy. Choose the size that takes your normal batch in one load with the basket in.
40 kHz or 28 kHz
Ultrasonic cleaning works by cavitation: the transducers vibrate the liquid, forming microscopic vacuum bubbles that collapse against the surface being cleaned. The lower the frequency, the larger and more forceful the bubbles. 40 kHz is the jewellery standard: it reaches prong undersides and chain-link interiors while staying gentle on platings and mounted stones. 28 kHz is for casting plaster, investment and heavy polishing compound, where force matters more than finesse. A casting house that also cleans finished pieces should specify the dual 28/40 kHz unit and switch modes rather than buying two machines.
Heater, timer and controls
- Heater. Unheated, up to 60 °C, or up to 80 °C. Warm liquid makes grease, wax and compound release in minutes instead of the half hour a cold bath takes. Specify 80 °C for a finishing room.
- Timer. 0 to 30 minutes in 1-minute steps with auto shut-off. Finished jewellery takes 3 to 10 minutes; casting plaster 10 to 20. The shut-off is what protects settings from being over-run.
- Controls. Mechanical timer, digital display, or a programmable multi-cycle controller with presets per piece type, which keeps results consistent across operators and shifts.
- Drain valve. Built in from 6 L upward, so solution changes do not mean tipping a full tank.
Construction and power
The tank, basket and lid are SUS304 stainless steel, which stands up to daily detergent, pickling solution and alkaline pre-plating solution. Transducers are sandwich-type piezoelectric: two on 2 to 6 L units, three on 9.5 to 15 L, and multiple arrays on 20 to 30 L, so there are no dead zones in the tank. The unit runs on 180 to 250 V AC, which covers the supply variation in most Indian towns; 110, 120, 220 and 240 V configurations at 50 or 60 Hz are available for export.
The product
All of the above is one product line: the Semsons Tech ultrasonic cleaner, from 0.6 L to 30 L, with a 1-year warranty and lifetime technical consultation, same-day dispatch from Mumbai and Rajkot, and the cleaning solutions to go with it. Bench units plug in and run; on-site setup support is available for 10 L and larger.
Frequently asked questions
What size ultrasonic cleaner should a jewellery showroom buy?
Most independent showrooms run a 2.85 L or 3 L tank, which takes a tray of rings or chains in one load. A multi-counter showroom, or one that cleans bangles and bridal sets, is better with 4.5 L or 6 L.
Which stones should not go in an ultrasonic cleaner?
Porous or fracture-filled stones such as emerald, opal, pearl, turquoise and coral, and any glued setting. Diamonds, sapphires, rubies, CZ and lab-grown diamonds are fine at the recommended 3 to 10 minute cycle.
Is 28 kHz or 40 kHz better for jewellery?
40 kHz for finished jewellery and mounted stones, because it is gentler on platings and settings. 28 kHz makes larger, more forceful bubbles and suits casting plaster and heavy compound. A dual-frequency unit switches between the two.