TH-18000 Custom-Built High-Capacity Gradient Mixer
| Origin | Shanghai, China |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Origin Category | Domestic (PRC) |
| Model | TH-18000 |
| Price | USD 1,165 (FOB Shanghai) |
| Dimensions (W×D×H) | 650 × 330 × 550 mm |
| Maximum Gradient Volume | 36,000 mL |
| Gradient Profile | Linear only |
| Flow Rate & Mixing Ratio | Continuously Adjustable via Dual Independent Peristaltic Pumps |
| Liquid Level Equilibration | Passive hydrostatic balancing between two reservoirs |
Overview
The TH-18000 Custom-Built High-Capacity Gradient Mixer is a precision-engineered laboratory device designed for the controlled, reproducible generation of linear concentration gradients in chromatographic and electrophoretic applications. Operating on the principle of dual-reservoir passive hydrostatic equilibration coupled with independently adjustable peristaltic pumping, the system maintains consistent liquid levels between concentrated and diluted solution chambers while enabling precise control over gradient slope, flow rate, and total eluent volume. Unlike digitally programmed gradient formers, the TH-18000 employs a robust mechanical architecture optimized for long-duration, high-volume gradient formation—particularly suited for preparative-scale column chromatography, density gradient centrifugation setup, and large-batch buffer exchange protocols requiring stable, low-pulsation delivery over extended timeframes (up to 48+ hours at nominal flow rates). Its design prioritizes operational stability, chemical compatibility with aqueous and mild organic solvent systems (e.g., up to 30% acetonitrile or methanol), and minimal operator intervention during gradient execution.
Key Features
- High-capacity gradient generation: Supports up to 36,000 mL total gradient volume across two interchangeable reservoirs (standard 20 L polypropylene carboys included)
- Dual independent peristaltic pump heads with calibrated roller compression adjustment—enabling fine-tuned control of relative flow contribution from each reservoir (0–100% mixing ratio)
- Passive hydrostatic level balancing mechanism eliminates need for active level sensors or feedback controllers, enhancing reliability and reducing maintenance points
- Mechanically stabilized gradient slope: Linear gradients are achieved through synchronized volumetric displacement; slope is determined by initial reservoir concentration differential and relative pump speed ratio
- Chemically resistant fluid path: Tubing (Pharmed® BPT or Norprene® A-60-F) and reservoir interfaces compatible with pH 2–12 aqueous buffers, saline solutions, glycerol gradients, and low-concentration organic modifiers
- Modular base frame with vibration-dampening feet and integrated tubing management channels for clean benchtop integration
Sample Compatibility & Compliance
The TH-18000 is validated for use with standard laboratory-grade aqueous buffers (Tris-HCl, phosphate, HEPES), sucrose, glycerol, and cesium chloride density media. It is not intended for use with strong oxidizers, halogenated solvents, or high-viscosity polymers (>100 cP at operating temperature). While the device itself carries no CE/UKCA marking or FDA clearance (as it is classified as a general-purpose lab accessory—not an IVD or medical device), its construction materials comply with ISO 10993-5 (cytotoxicity) and USP Class VI plastic standards. Documentation supports GLP-compliant recordkeeping when used within validated chromatographic workflows; users are responsible for verifying gradient accuracy via offline conductivity or UV absorbance monitoring per internal SOPs.
Software & Data Management
The TH-18000 operates as a standalone analog instrument without embedded microcontroller or digital interface. Gradient parameters—including target volume, mixing ratio, and estimated run time—are calculated manually using provided nomograms and verified via gravimetric or volumetric endpoint measurement. For traceability in regulated environments, laboratories may integrate the unit with external flow meters (e.g., Bronkhorst CORI-FLOW) or data loggers (Omega OM-DAQPRO-5300) via 4–20 mA or pulse output adapters (sold separately). Audit trails must be maintained manually or via LIMS-integrated electronic notebooks adhering to 21 CFR Part 11 requirements where applicable.
Applications
- Preparative gel filtration and ion-exchange chromatography requiring multi-liter linear salt or pH gradients
- Formation of sucrose or glycerol density gradients for ultracentrifugation of macromolecular complexes
- Buffer exchange and diafiltration support in protein purification scale-up (e.g., prior to SEC-MALS or AUC)
- Method development for HPLC and FPLC systems where reproducible large-volume gradient testing is required
- Educational demonstration of gradient physics principles—including diffusion-limited mixing, residence time distribution, and pump synchronization dynamics
FAQ
Does the TH-18000 support nonlinear (curved) gradient profiles?
No. The mechanical design is optimized exclusively for linear gradients. Nonlinear profiles require external programmable pump systems or digital gradient mixers.
Can the TH-18000 be connected to an HPLC system directly?
Yes—via standard 1/4″ OD PTFE or stainless-steel transfer lines; however, backpressure exceeding 2 bar may affect flow consistency and is not recommended without inline pressure regulation.
What maintenance is required for long-term operation?
Monthly inspection of tubing wear, quarterly recalibration of pump head compression, and biannual replacement of peristaltic tubing (typical lifespan: 500–800 hours at 30 rpm continuous duty).
Is technical documentation available in English with metrological traceability data?
Yes—full English user manual, dimensional drawings, material compliance certificates (RoHS, REACH), and factory calibration records (flow rate verification at 5, 15, and 30 rpm per channel) are supplied with each unit.
