RV-21A Rotary Evaporator — Compact 2L with DC Brushless Motor and 300 rpm for Small-Scale Labs

The RV-21A is designed as a compact rotary evaporator specifically optimised for small-scale laboratory environments where bench space is limited. Its streamlined structure accommodates a 1L rotary flask and 1L collection bottle within a minimal footprint — making it suitable for analytical chemistry workstations, academic teaching laboratories, and small research group installations where a full-size 5L or 20L rotary evaporator would be impractical. The compact design does not compromise on core performance specifications — the RV-21A achieves the same 8 mbar ultimate vacuum as larger models in the RV Series.

The RV-21A uses a DC brushless motor to drive the rotary flask — a motor technology that offers significant advantages over brushed motor systems in laboratory equipment. Brushless motors eliminate the carbon brush wear mechanism that causes gradual performance degradation and requires periodic maintenance in brushed motor designs. The result is more consistent torque delivery across the full 20–300 rpm speed range, quieter operation, longer motor service life, and reduced maintenance requirements — all relevant benefits for a laboratory evaporator expected to run reliably over thousands of operating hours.

The RV-21A is operated via an LCD display combined with an intuitive knob control interface — providing clear real-time visibility of rotation speed and bath temperature setpoints during evaporation. The knob control enables smooth, continuous speed adjustment across the 20–300 rpm range without the step increments of push-button systems, allowing operators to find the optimal rotation speed for their specific solvent and flask fill volume. The LCD display provides unambiguous parameter readout at the bench even under the bright lighting conditions of active laboratory environments.

The RV-21A's automatic lifting mechanism raises and lowers the rotary flask into and out of the heating bath with controlled, motorised movement — eliminating the manual effort and inconsistency of manual lift systems. The automatic lift ensures that flask immersion depth is reproducible between runs and between operators, contributing to consistent evaporation rates across repeated processing sessions. It also allows the flask to be rapidly raised out of the bath in response to alarm conditions or unexpected process events, protecting heat-sensitive samples from over-exposure to the heating bath.

The RV-21A's vacuum system incorporates PTFE (polytetrafluoroethylene) sealing throughout the rotary joint and vacuum path — providing chemical resistance to the broad range of organic solvents, acids, and corrosive chemicals commonly processed in rotary evaporators. PTFE's inertness prevents seal degradation, swelling, or permeation when exposed to aggressive laboratory solvents including acetone, dichloromethane, ethanol, methanol, hexane, and toluene — maintaining the vacuum integrity of the 8 mbar system across repeated solvent processing cycles and extending seal service life compared to standard rubber or silicone seal alternatives.

The RV-21A's rotation system delivers smooth, vibration-free orbital motion across its full 20–300 rpm range — ensuring consistent thin-film formation on the inner surface of the rotary flask that is the primary heat transfer and evaporation mechanism in rotary evaporation. Unstable or vibrating rotation disrupts the thin-film layer, reduces the effective evaporation area, and can cause sample bumping — a sudden, violent eruption of boiling liquid that contaminates the condenser and causes sample loss. The RV-21A's stable rotation mechanism prevents these disruptions and supports consistent, bump-free evaporation across the full speed range.