Chengmeng CM-24T 24-Position Corrosion-Resistant Water Bath Nitrogen Evaporator

Overview

The Chengmeng CM-24T is a 24-position corrosion-resistant water bath nitrogen evaporator engineered for precise, reproducible solvent removal in analytical laboratories performing sample preparation for GC, HPLC, LC-MS, and environmental testing workflows. It operates on the principle of gentle inert gas sweeping—introducing controlled streams of nitrogen or compressed air across the surface of heated liquid samples to accelerate evaporation without thermal degradation. Unlike dry-block or aluminum-block systems, the water bath design ensures uniform, low-gradient heating (±0.5 °C stability), minimizing thermal shock and preserving thermolabile analytes. The unit integrates a digitally regulated PID temperature controller with over-temperature cutoff and anti-dry-burn protection, ensuring operational safety during unattended runs. Its fully PTFE-coated architecture—including the bath chamber, sample holder, gas distribution manifold, and adjustable needle guides—enables reliable use with aggressive solvents (e.g., concentrated HCl, HF, perchloric acid) and acidic/basic digestates common in EPA Method 3050B, ASTM D5673, or ISO 11843-2 applications.

Key Features

• 24-position circular sample rack with 360° rotation and independent vertical lift—facilitates ergonomic access and eliminates cross-contamination between adjacent tubes.
• PTFE-coated stainless steel construction throughout critical wetted surfaces: bath vessel, support disc, gas manifolds, and guide sleeves—certified resistant to pH 0–14 exposure per ASTM D1308 and ISO 2812-2 accelerated corrosion testing.
• Individual PTFE-sheathed stainless steel needles (18 gauge, 120 mm length) with integrated needle valves—allow precise, position-specific flow adjustment from 0 to 330 mL/min per channel, verified via calibrated rotameter (full-scale 15 L/min).
• Dual independent gas inlets supporting simultaneous connection to nitrogen (for oxygen-sensitive analytes) and compressed air (for routine, non-oxidizable matrices), each routed through pressure-regulated SMC TUS transparent silicone-free tubing (ISO 8573-1 Class 0 certified).
• Programmable digital timer (0–9999 minutes) synchronized with temperature control; supports multi-step protocols where ramp-and-hold evaporation profiles are required per USP method validation guidelines.
• Modular height-adjustable gas needle assembly—each needle independently raised/lowered to maintain optimal distance (10–15 mm above meniscus) regardless of tube diameter (10–29 mm OD) or fill volume (1–50 mL).

Sample Compatibility & Compliance

The CM-24T accommodates standard borosilicate glass test tubes, conical centrifuge tubes (15–50 mL), and small-volume vials (e.g., 2 mL autosampler vials with crimp caps). Its PTFE-coated bath and rack meet material compatibility requirements for EPA SW-846 Methods 3510C (liquid-liquid extraction) and 3550C (Soxhlet extraction), as well as ISO/IEC 17025-accredited labs conducting GLP-compliant residue analysis. All electrical components comply with IEC 61010-1:2010 safety standards for laboratory equipment. While not FDA 21 CFR Part 11–validated out-of-the-box, the system’s deterministic timer, non-volatile temperature logging (via optional RS-232/USB interface), and immutable parameter settings support audit-ready documentation when integrated into validated SOPs.

Software & Data Management

The CM-24T features an embedded LCD interface with real-time display of setpoint temperature, actual bath temperature, elapsed time, and remaining runtime. No proprietary software is required for operation; however, optional data-logging modules (sold separately) provide timestamped CSV export of temperature history at 10-second intervals—compatible with LIMS platforms such as LabWare LIMS or Thermo Fisher SampleManager. All configuration changes (setpoint, timer, alarm thresholds) are stored in non-volatile memory and survive power cycling. Firmware updates are performed via USB flash drive using signed binary files—ensuring integrity per NIST SP 800-193 guidelines.

Applications

• Concentration of pesticide extracts prior to GC-ECD analysis (AOAC 2007.01).
• Post-digestion cleanup of heavy metals in soil leachates (EPA Method 6010D).
• Pre-concentration of PFAS compounds in aqueous environmental samples (EPA Method 537.1).
• Removal of organic solvents from derivatized amino acid standards prior to chiral HPLC separation.
• Routine evaporation of ethanol/water mixtures in pharmaceutical stability-indicating assays (ICH Q5C).

FAQ

Can the CM-24T be used with hydrofluoric acid (HF) solutions?

Yes—the entire fluid path, including the bath liner and gas delivery nozzles, is uniformly coated with ≥50 µm electrostatically applied PTFE per ASTM D7234, providing validated resistance to HF concentrations up to 48% at 60 °C for ≤2 hours.
Is the water bath level sensor field-replaceable?

Yes—the float-type level switch is accessible behind the rear service panel and ships as a spare part (P/N CM-LV-01); replacement requires no calibration.
Does the unit support external temperature probe input for bath verification?

No—temperature feedback is derived solely from the internal Pt100 sensor embedded in the bath wall; however, the system includes a dedicated 2-mm diameter calibration port for insertion of an external traceable thermometer per ISO/IEC 17025 Clause 6.5.2.
What maintenance intervals are recommended for the gas manifold?

Inspect PTFE needle valve seats quarterly using a 10× magnifier; clean with IPA-moistened lint-free swab if particulate accumulation is observed. Replace needle assemblies annually or after 5000 operating cycles, whichever occurs first.
Can the CM-24T be integrated into a robotic liquid handling workstation?

Yes—dry-contact relay outputs (NO/NC) are provided for “Ready,” “Heating,” and “Alarm” states; analog 0–10 V output mirrors bath temperature for PLC interfacing.