3920 Low Humidity Generation System
Description
The 3920 Low Humidity Generation System is a self-contained system capable of producing atmospheres of known humidity utilizing the fundamental NIST-proven “two-pressure” “two-temperature” humidity generation principles. This system is capable of continuously supplying frost point, dew point, parts per million, relative humidity and other calculated values for instrument calibration and evaluation as well as for precision environmental testing. This system will automatically generate manually entered humidity setpoints as well as user created multipoint profiles. Visual indications of system status are displayed in real time on the computer monitor.
PRINCIPLE OF OPERATION
The humidity generation process involves saturating nitrogen or CO2 free air with water vapor at a known temperature and pressure. The saturated gas is then reduced to test pressure and warmed to test temperature. The measurements of saturation temperature, saturation pressure, test temperature, and test pressure are used in the determination of all hygrometric parameters. System precision is determined by the accuracy and stability of the temperature and pressure measurements. The system does not use or rely on the measurement of water vapor content for calculation or control.
APPLICATIONS
Chilled Mirror Hygrometers: Connecting the generator output to a chilled mirror hygrometer allows the user to verify the mirror temperature measurement accuracy; perform operational checks on the hygrometer components; determine whether the hygrometer is controlling the mirror in the liquid phase or ice phase when operating below 0 °C; determine if the hygrometer is correctly calculating other humidity parameters; determine hygrometer repeatability, stability, and drift characteristics.
Humidity Sensors and Electrolytic Hygrometers: Connecting the generator output to special fixtures, hygrometer sampling systems, or individual sensors allows the user to calibrate and/or characterize humidity sensitivity; perform operational checks such as the sensing systems capability to correctly calculate and display other humidity parameters; determine repeatability, stability, hysteresis and/or drift characteristics of various humidity sensing systems.
Environmental Testing: The 3920 can serve as a test bed for evaluation and R&D of humidity sensors, humidity sensing systems, and humidity sensitive products, e.g., polymers, composites, film, magnetic medium, pharmaceuticals, soil hydrology, consumables, electronics, optics, etc.
Key Features
- Traceable to SI
- Based on NIST “Two-Pressure” Principle
- High Flow Capability of 10 L/min
- ControLog® Embedded Automation Software
- Generate: Frost Point, Dew Point, PPM, %RH
- HumiCalc® Mathematical Engine
- Calculated Real-Time Uncertainty
- Calculated Water Capacity / Usage
- Ability to Operate Using External Computer
- VCR® Metal Gasket Face Seal Fittings
- Diaphragm-sealed Control Valves
- Multi-Point Touch LCD
Specification
Frost Point Temperature Range: ....................................................................... -95 to 0.01 °C
Dew Point Temperature Range: ........................................................................... -50 to 10 °C
Parts Per Million Range:..........................................................................0.04 to 12300 PPMv
Relative Humidity Range: ......................................................................... 0.00003% to ~50%
Temperature Specification: .........................................................................................0.027 °C
Saturation Temperature Range: ........................................................................... -80 to 12 °C
Saturation Temperature Control Stability: ................................................................ 0.008 °C
Saturation Temperature Cooling Rate: from 12 to -80 °C ........... 0.5 °C per Minute (average)
Saturation Temperature Heating Rate: from -80 to 12 °C ........... 0.5 °C per Minute (average)
Test Temperature Range (measured):....................................................................... 0 to 50 °C
Saturation Pressure Range: ....................................................................~Ambient to 250 psiA
Saturation Pressure Specification: ..............................................................0.02% of full scale
Test Pressure Range (measured): ...............................................................Ambient to 50 psiA
Test Pressure Specification: ........................................................................ 0.02% of full scale
Gas Type: ........................................................................... Gaseous Nitrogen or CO2 free Air
Gas Flow Rate Range: .....................................................................................0.5 to 10 SLPM
Gas Flow Rate Specification:...........................................................................2% of full scale
Display Resolution:.......................................................................................................... 0.001
Refrigeration: .........................................................1/3 HP R-134A & 1/3 HP R-23 in cascade
Heating:............................................................................................Stainless Steel Immersion
Test Port & Gas Inlet: ...................................................................... 1/4 Inch Swagelok VCR®
Physical Dimensions: ................ 38” H x 23” W x 35” D (965.2 mm x 584.2 mm x 889 mm)
UNCERTAINTY
Dew Point Uncertainty: -50 °C to 10 °C................................................... 0.01% |R| + 0.07 °C
Frost Point Uncertainty: ≥-90 °C .............................................................. 0.05% |R| + 0.07 °C
Frost Point Uncertainty: < -90 °C......................................................................2% |R| -1.7 °C
Test Temperature Uncertainty: 0 to 50 °C ..................................................................0.034 °C
UTILITIES
Electrical Power: .................................................................220 ±20 V~, 10 A, 1 Ø, 50/60 Hz
Gas Supply: ......................................................................... 80 psiG to 300 psiG @ 10 L/min
Floor Space: ...................................................................................................... 9 ft2 (0.84 m2)
ENVIRONMENTAL
Operating Temperature: ........................................................................................ 15 to 30 °C
Storage Temperature: .............................................................................................. 0 to 50 °C
Humidity: ................................................................................ 5 to 95% RH Non-condensing
Downloads
Brochures, Manual, Quick Start Guides, Software etc.
