SRD NWC-4 Capillary Viscometer System with Precision Thermostatic Bath
| Brand | SRD |
|---|---|
| Model | NWC-4 |
| Instrument Type | Capillary Viscometer System |
| Viscosity Measurement Range | 0.01–999.99 s (efflux time) |
| Temperature Control Range | 0–80 °C |
| Temperature Resolution | 0.01 °C |
| Temperature Stability | ±0.01 °C (within ambient ±30 °C) |
| Temperature Uniformity | ±0.01 °C (within bath volume) |
| Timing Range | 0–999.99 s |
| Timing Resolution | 0.01 s |
| Timing Accuracy | ±0.2 s per 999 s |
| Bath Volume | 42 L |
| Bath Chamber Dimensions | 640 × 195 × 340 mm (L×W×H) |
| Observation Window | 475 × 270 mm |
| Heating Power | 1 kW |
| Refrigeration Unit (XWC-100/1) | Cooling Capacity: 250 kcal/h |
| Minimum Output Temperature | <−15 °C (short-circuit condition) |
| Power Supply | Main Unit: 220 V, 6 A, 50 Hz |
| Chiller | 220 V, 3 A, 50 Hz |
| Construction | Powder-coated steel chassis with stainless-steel front panel |
Overview
The SRD NWC-4 Capillary Viscometer System is a precision-engineered laboratory instrument designed for kinematic viscosity determination of transparent and opaque Newtonian liquids—primarily polymer solutions, synthetic fiber spinning dopes, petrochemical feedstocks, pharmaceutical solvents, and biopolymer formulations—using standardized capillary efflux methods. It operates on the principle of Poiseuille flow through calibrated glass capillaries (e.g., Ubbelohde, Ostwald, or Cannon-Fenske types), where viscosity is derived from measured efflux time under gravity-driven laminar flow at rigorously controlled temperature. The system integrates two functionally independent but mechanically coupled subsystems: a high-stability thermostatic bath and a modular viscometer mounting & timing station. Its core design objective is to meet the stringent thermal and temporal requirements of ASTM D445, ISO 3104, JIS K 2283, and GB/T 265—particularly the ±0.01 °C temperature uniformity and stability thresholds mandated for Class I reference baths in viscosity standardization.
Key Features
- Precision thermostatic bath with dual-mode (heating + refrigeration) temperature control, enabling operation across 0–80 °C without external cooling water or ambient dependency.
- Integrated XWC-100/1 compression-based chiller unit delivering stable sub-ambient temperatures down to <−15 °C—eliminating limitations of thermoelectric (Peltier) systems, including low cooling capacity, pressure-dependent water supply, and thermal hysteresis.
- Liquid crystal display with real-time temperature readout and digital correction capability (<0.10 °C offset compensation), ensuring traceable calibration alignment with national metrological standards.
- 42-liter bath volume with optimized fluid circulation geometry, achieving ±0.01 °C spatial uniformity across the full working zone—verified per ISO/IEC 17025-compliant validation protocols.
- Dual large-format observation windows (475 × 270 mm), backlit by diffused white LED illumination, enabling unambiguous visual alignment of capillary verticality and meniscus tracking during efflux.
- Microprocessor-controlled timing module with six independently assignable start/stop buttons, 0.01-second resolution, and documented timing accuracy of ±0.2 s over full 999.99-second range—satisfying GLP audit requirements for manual timing procedures.
Sample Compatibility & Compliance
The NWC-4 accommodates standard ASTM/ISO-compliant capillary viscometers (including suspended-level and dilution types) up to 400 mm in length. Its bath geometry supports simultaneous immersion of up to four viscometers with unobstructed flow paths and minimal convective interference. The system is routinely deployed in QC laboratories performing routine testing of PET melt solutions (inherent viscosity), lubricant base stocks (kinematic viscosity), and polysaccharide solutions (relative viscosity). All thermal and timing performance metrics are validated against ISO/IEC 17025-accredited reference standards. The bath’s thermal stability profile complies with ASTM E1137 (Specification for Laboratory Thermometers) and supports full traceability to NIM (National Institute of Metrology, China) certified reference materials. While not inherently 21 CFR Part 11 compliant, its timing logs and temperature records can be exported in CSV format for integration into validated LIMS or ELN environments supporting electronic record retention.
Software & Data Management
The NWC-4 operates as a standalone hardware platform with no embedded operating system or proprietary software stack. All user interaction occurs via tactile pushbuttons and an integrated LCD interface. Temperature setpoints, correction offsets, and timing events are stored in non-volatile memory with battery-backed retention. Timing data is displayed and retained locally for immediate transcription; no automatic data export or USB/RS-232 connectivity is provided. This architecture prioritizes operational robustness, electromagnetic immunity, and long-term serviceability—key considerations for regulated industrial labs where firmware updates, cybersecurity vulnerabilities, or OS obsolescence pose unacceptable validation risks. For laboratories requiring automated data capture, third-party digital stopwatch interfaces or machine vision-based meniscus detection systems may be externally integrated using TTL trigger outputs (available upon request).
Applications
- Determination of inherent viscosity (IV) and relative viscosity (RV) of polyethylene terephthalate (PET), polyamide (PA), and polyacrylonitrile (PAN) solutions per ISO 1628-1 and GB/T 14190.
- Kinematic viscosity measurement of mineral oils, synthetic lubricants, and fuel blends per ASTM D445 and ISO 3104.
- Quality control of cellulose derivatives (e.g., methylcellulose, hydroxypropyl methylcellulose) used in pharmaceutical excipients and food thickeners.
- Research-scale rheological screening of dilute polymer solutions prior to rotational rheometry or light scattering analysis.
- Calibration verification of secondary viscometer standards in metrology labs accredited to ISO/IEC 17025.
FAQ
What capillary viscometer types are compatible with the NWC-4 bath?
Ubbelohde, Ostwald, Cannon-Fenske, and micro-Ubbelohde viscometers—provided their physical dimensions allow full immersion within the 640 × 195 × 340 mm chamber and clearance from bath walls.
Does the system support automatic data logging or network connectivity?
No. The NWC-4 is a manually operated, hardware-only platform. Timing and temperature data must be recorded externally. Optional TTL-triggered data acquisition modules are available for integration with custom DAQ systems.
Can the chiller unit (XWC-100/1) operate independently of the main bath?
Yes. The XWC-100/1 is a fully self-contained refrigeration module with independent power input and fluid output ports, usable as a standalone cold source for other equipment requiring stable sub-ambient circulation.
Is the temperature display traceable to national standards?
The LCD display incorporates digital offset correction (±0.10 °C max error), enabling alignment with NIM-certified reference thermometers. Full bath validation requires periodic verification using calibrated PT100 probes per ISO/IEC 17025 procedures.
What maintenance is required for long-term thermal stability?
Annual recalibration of the internal Pt100 sensor and verification of refrigerant charge integrity are recommended. Bath fluid (typically water/glycol mix) should be replaced every 12 months to prevent microbial growth and thermal degradation.
