Bandelin SONOREX SUPER RK 31 Ultrasonic Bath, 0.9 L, 35 kHz, 329

Sensor tips, small cannulas, jewellery or individual cuvettes do not require a large bath for ultrasonic cleaning; rather, they need a bath that delivers uniform cavitation to every corner of the tank. With a total capacity of 0.9 l, the Bandelin SONOREX SUPER RK 31 is the smallest model in the SUPER RK series and is designed specifically for these small-item cleaning tasks in laboratories, medical practices and workshops.

Small tank, noticeable cavitation

At an operating frequency of 35 kHz, the RK 31 generates a peak power of 160 watts at a rated power of 40 watts, distributed across a single transducer system. This is sufficient for the small tank volume of 0.9 l (working capacity 0.6 l); larger SUPER RK models, such as the RK 514 BH, on the other hand, operate with four transducers covering a significantly larger area. The automatic SweepTec function continuously adjusts the frequency slightly, thereby preventing standing waves in the ultrasonic field; as a result, the cleaning effect remains uniform even in small volumes.

Thin stainless steel bath for the laboratory bench

The ultrasonic bath is made of 1.4301 stainless steel with a thickness of 0.8 millimetres; the housing is made from the same material. The internal dimensions of 190 x 85 x 60 mm and the compact external dimensions of 205 x 100 x 180 mm ensure that the unit, with a net weight of 2.2 kg, can still be accommodated even on already occupied work surfaces. The RK 31 is operated via a robust rotary handle; the timer ranges from 1 to 15 minutes in 5 per cent increments, and continuous operation is also available.

No drain, no heating, but simple

The data sheet explicitly states that this model has no drain; a ball valve is not provided for this size. With a capacity of 0.9 l, the basin can be emptied directly over the edge after the cleaning cycle; an additional connection would be rather cumbersome in this case. Similarly, the RK 31 does not feature a heating element. Anyone requiring heating for cleaning in the same size will find the RK 100 H, the next larger, heated model in the same series.

Selection guide for the SUPER RK series

The SUPER RK series from Bandelin covers a wide range: from the RK 31 with a 0.9-litre capacity to the RK 1050 with a total capacity of 58 l. If you are only cleaning individual small parts, sensor tips or cuvettes, the RK 31 is the right choice. If the batch size increases to include several instruments or small glass vessels, it is worth considering the RK 100 H (3.0 l, heated) or the RK 103 H (4.0 l, heated and with a drain). For entire sieves or beakers, the larger models from the RK 510 (9.7 l) upwards are the more suitable choice.

SUPER RK, DIGITEC DT and smart ST compared

In addition to the SUPER RK series with classic rotary knob control, Bandelin offers the DIGITEC DT series with push-button control, an LED display and DEGAS degassing, as well as the smart ST series with a touchscreen, finely adjustable power control and programme memory. Those who only clean occasionally and value straightforward, robust operation would be well advised to choose a SUPER RK model such as the RK 31. LT Laborhandel also stocks Elma Elmasonic ultrasonic baths, an alternative for laboratories already equipped with this brand.

Use and maintenance

The working capacity of 0.6 l is deliberately set below the total capacity of 0.9 l, as space must be left for the items being cleaned when filling the bath; otherwise, the liquid will spill over the rim. As for the cleaning solution itself, Bandelin offers its own TICKOPUR range of concentrates; for the SONOREX PR series of pipette cleaners, this is included in the set, whilst a suitable concentrate for the RK 31 must be purchased separately. Freshly prepared cleaning fluid contains dissolved air, which initially dampens cavitation; a short pre-run in continuous operation before the actual cleaning process dispels it. The stainless-steel basin is compatible with most aqueous cleaning agents; however, abrasive sponges or chlorine-based agents should still be avoided. At the end of the working day, it is best to empty and dry the basin.

Typical applications

• Cleaning of small sensor tips, cannulas and needles
• Precision cleaning of jewellery and small metal parts
• Pre-cleaning of precision mechanical components and watch movements
• Cleaning individual cuvettes or small sample vessels in the laboratory

Frequently asked questions

Is the SONOREX SUPER RK 31 heated? No, the RK 31 is the unheated version of this model. A heated variant with a similar volume is the RK 100 H.

Does the unit have a drain? No, the technical data sheet does not specify a ball valve for the RK 31; with a capacity of 0.9 l, the bath is emptied directly.

Is the RK 31 a medical device? Yes, it is classified as a Class I medical device in accordance with Regulation (EU) 2017/745 and is also CE-compliant with the Low Voltage, EMC and RoHS Directives.

Are the basket and lid included in the scope of delivery? No, the K 08 hanging basket and the D 08 lid are available separately as accessories.

Technical details

Scope of delivery

• 1x Bandelin SONOREX SUPER RK 31 ultrasonic bath
• Fixed mains lead (2 m)
• Instructions for use

The hanging basket and lid are not included in the scope of delivery and are available separately.

Individual requirements and procurement service

For the K 08 hanging basket, the D 08 lid or a larger SUPER RK model, a bespoke procurement request is required. You can use LT Laborhandel’s procurement service to request a quote for suitable accessories, a replacement basket or another model from the SONOREX range.