Thunder Scientific 2900 Automated Two Pressure Humidity Generation Owner’s Manual

: July 25, 2024
: Thunder Scientific

Table of Contents

Thunder Scientific 2900 Automated Two Pressure Humidity Generation
Product Usage Instructions
FAQ
FEATURES
DESCRIPTION
PRINCIPLE OF OPERATION
APPLICATIONS
Dimension
SPECIFICATIONS
CONTACT
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Thunder Scientific 2900 Automated Two Pressure Humidity Generation

Product Usage Instructions

The 2900 Humidity Generation System uses a two-pressure process involving saturation pressure, test temperature, and test pressure to determine hygrometric parameters.
The system is controlled by the embedded software application controLog, accessible through a multi-point touch LCD. Users can set parameters such as temperature, pressure, and humidity units (hr, cfm, cfh) through the Control and Calculated Humidity tabs.
The system maintains stable temperature using PID algorithms and a water/glycol jacked test chamber. A centrifugal pump circulates fluid through the chamber and saturator at a controlled rate of approximately 14 gallons per minute.
Pressure and mass flow are controlled by computer actuation of valve assemblies. Saturation pressure and mass flow are continuously measured and controlled using PID algorithms similar to temperature control.
The accuracy of the generator depends on the proper calibration of temperature and pressure transducers. The system includes an integrated software calibration scheme for calibrating probes and transducers while connected to the generator.
The system includes a test chamber with dimensions of 12 x 12 x 10 inches. The pressure range in the chamber is ambient.

FAQ

Q: What applications is the Model 2900 suitable for?
A: The Model 2900 is ideal for environmental testing, including evaluation and R&D of humidity sensors, humidity sensing systems, and humidity-sensitive products such as polymers, composites, electronics, optics, and more.

Model 2900

Automated “Two-Pressure”
Humidity Generation System

FEATURES

Traceable to SI 1
0.5% of Reading RH Uncertainty 6
High Flow Capability of 50 L/min
Based on the NIST “Two-Pressure” Principle
ControLog® Embedded Automation Software
Automatically Applies Enhancement Factors
HumiCalc® with Uncertainty Mathematical Engine
Generate Multipoint Profiles
Externally Driven Chamber Fan
10.1” Multi-point Touch LCD
Fluid Jacketed Chamber Door
Window Chamber Door Option (WDA)

DESCRIPTION

The 2900 Humidity Generation System is a self-contained system capable of producing atmospheres of known humidity using the fundamental “two-pressure” principle. This system is capable of continuously supplying relative humidity, dew point, frost point, parts per million, or other calculated values for instrument calibration and evaluation as well as for precision environmental testing. This system will automatically generate manually entered humidity and temperature set points as well as user-created multipoint profiles. All desired humidity, temperatures, flow rates, and time intervals may be programmed.

PRINCIPLE OF OPERATION

The “two-pressure” humidity generation process involves saturating air or nitrogen with water vapor at a known temperature and pressure. The saturated high-pressure air flows from the saturator, through a pressure-reducing valve, where the air is isothermally reduced to test pressure at test temperature. Humidity generation is dependent on the measurement of temperature and pressure, not on the amount of water vapor measured in the air. System uncertainty is determined by the temperature and pressure uncertainties, and on the stability and uniformity of the measurements. When setpoint equilibration has been reached, the indication of saturation temperature, saturation pressure, test temperature, and test pressure, are used in the determination of all hygrometric parameters.

COMPUTER/CONTROL SYSTEM

The 2900 Humidity Generation System encompasses a high-performance stand-alone Control System that performs all functions required for humidity generation and control. The Control System employs 24-bit I/O modules with integrated signal conditioning to acquire data and uses serial interfaces to transducers and stepper motors to control the operation of generating humidity. The Control System utilizes an embedded operating system in conjunction with specialty software to control and interface with the human-to-machine interface (HMI) computer running ControLog. control is an embedded software application that fully automates the operation of the 2900 Humidity Generation System and allows various device connections through many different interfaces. ControLog uses Thunder Scientific’s HumiCalc with Uncertainty as its mathematical engine for computing all humidity values and real-time uncertainties. Data from the generator and attached devices is automatically retrieved and stored for viewing in either numerical or graphical format in real-time or post-process. Data can be transferred off the system via a USB drive for further viewing, post-processing, and printing using an external Windows PC. The ControLog software also provides the primary interface to the operator via the multi-point touch LCD which allows the user to select settings like pressure, temperature, and flow units. Other settings are °C, °F, atm, Pa, hPa, kPa, L/min, L/ hr, cfm, and cfh. Humidity is calculated and displayed in percent relative humidity (%RH). The Parameter Tab is the primary interface for the user and is divided in two sections, Control and Calculated Humidity. Within each tab there are two different tiles, the Setpoint Tile is for the user to enter the desired setpoints and a Value Tile displays the Actual Value.

Temperature Control: The 2900 humidity generation system incorporates a water/glycol jacked test chamber for extremely stable temperature control. The system uses PID (proportional-integral-derivative) algorithms to control the temperature of the chamber fluid as it is pumped around the test chamber and through the saturator at the rate of approximately 14 gallons per minute by a magnetically coupled centrifugal pump.

Pressure and Flow Control: Pressure control and mass flow control are accomplished through computer actuation of electromechanical valve assemblies. Saturation pressure and mass flow are measured continuously and controlled using PID algorithms similar to those employed in temperature control.

Calibration: Proper calibration of the temperature and pressure transducers ultimately determines the accuracy of the generator. The humidity generator employs an integrated software calibration scheme allowing the 2900’s probes and transducers to be calibrated while they are electrically connected to the humidity generator. Coefficients for each transducer are calculated by the computer and stored to memory.

TEST CHAMBER
The 2900 humidity generating system incorporates a test chamber, with internal dimensions of 12” x 12” x 10”. Test chamber pressure range is ambient. Access is available through two 1.875” diameter ports located on the right side. An externally driven, variable-speed, chamber fan is incorporated into the rear wall of the test chamber to reduce thermal gradients. The test chamber accommodates various solid-state sensors, sensing systems, chilled mirror hygrometers, as well as material samples for environmental testing. Virtually any humidity and temperature may be generated, for long periods, within the operational limits of the generator. The output or recording of the device under test may then be compared with the generator’s data for analysis.

APPLICATIONS

Humidity Sensors and Chart Recorders: Insert humidity probes through a test port in the chamber or install the sensing systems into the chamber to: determine humidity calibration accuracy and/or characterize humidity sensitivity by subjecting the humidity sensor to a variety of humidity levels; perform operational checks such as the sensing systems capability to correctly calculate and display other humidity parameters; determine the repeatability, stability, hysteresis, and drift characteristics of various humidity sensing systems.
Chilled Mirror Hygrometers: Install the actual chilled mirror head into the chamber or insert a sample tube through the test port and draw a sample through the chilled mirror head to: verify mirror temperature measurement calibration when the hygrometer is in thermal equilibrium with its environment; perform operational checks of the heat pump and optical components before and after mirror cleaning and balancing; determine whether the hygrometer is controlling the mirror deposit in the liquid phase or ice phase when operating at dew and frost points below 0 °C; determine if the hygrometer is correctly calculating other humidity parameters; determine hygrometer’s repeatability, stability, and drift characteristics.
Environmental Testing: 2900 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.

Dimension

Automated Humidity Generation System

SPECIFICATIONS

Relative Humidity Range : ……………………………………….. 10 to 95 %RH, 10 to 40 L/min
Relative Humidity Range : ……………………………………….. 95 to 98 %RH, 10 to 20 L/min
Frost Point Temperature Range : ………………………………………………………. -33.60 to 0 °C
Dew Point Temperature Range : …………………………………………………….. -36.94 to 70 °C
Chamber Fluid Temperature Range : …………………………………………………… -10 to 72 °C
Chamber Fluid Temperature Control Stability : …………………………………………. 0.002 °C
Chamber Temperature Uniformity : …………………………………………………………. < 0.04 °C
Chamber Fluid Temperature Heating Rate : -10 to 72 °C………..0.5 °C per Minute (avg.)
Chamber Fluid Temperature Cooling Rate : 72 to 0 °C……………0.5 °C per Minute (avg.)
Chamber Fluid Temperature Cooling Rate : 0 to -10 °C………….0.2 °C per Minute (avg.)
Temperature Specification :……………………………………………………………………… 0.027 °C
Gas Type : ……………………………………………………………………………………. Air or Nitrogen
Gas Pressure Rating : (MAWP)………………………………………………………………… 175 psiG
Gas Flow Rate Range :……………………………………………………………………. 10 to 50 L/min
Gas Flow Rate Specification :…………………………………………………………. 5% of full scale
Saturation Pressure Range :…………………………………………………….. Ambient to 160 psiA
Saturation Pressure Specification :………………………………………………. 0.02% of full scale
Test Chamber Pressure Range :………………………………………………………………… Ambient
Display Resolution :……………………………………………………………………………………… 0.001
Chamber Window Option :…………………………………………… 6” x 6” (152 mm x 152 mm)
Test Chamber Dimensions :…………. 12” x 12” x 10” (304.8 mm x 304.8 mm x 254 mm)
Physical Dimensions :……… 22” H x 36” W x 23” D (558.8 mm x 432 mm x 584.2 mm)

UNCERTAINTY

RH Uncertainty : 10 to 95 %RH, 0 to 70 °C, 10 to 40 L/min………………. 0.5% of reading
RH Uncertainty : 95 to 98 %RH, 0 to 70 °C, 10 to 20 L/min………………. 0.5% of reading
Dew/Frost Point Uncertainty : < 0 °C, 10 to 40 L/min…………………………………….0.05 °C
Dew Point Uncertainty : 0 to 70 °C, 10 to 40 L/min……………………………………….0.08 °C
Test Chamber Temperature Uncertainty : -10 to 72 °C………………………………… 0.031 °C
Test Chamber Pressure Uncertainty : Ambient…………………………………………..0.007 psiA

UTILITIES

Electrical Power : …………………………………… 200-230/210-240 V~, 10 A, 1 Ø, 50/60 Hz
Gas Supply : ……………………………………………………………………….. 175 psiG @ 50 L/min

ENVIRONMENTAL

Operating Temperature : ……………………………………………………………………… 15 to 30 °C
Storage Temperature : …………………………………………………………………………… 0 to 50 °C
Humidity: ………………………………………………………………. 5 to 95% RH Non-condensing

Traceable to the International System of Units (SI) through a national metrology institute (NIST) recognized through a CIPM MRA.
Only the glycol/water heat transfer fluid circulating the chamber is controlled to setpoint via the saturation temperature probe. Chamber temperature inside the chamber may vary depending on door configuration, setup, and uniformity. Note: the 2900 can only operate for a finite amount of time at or below 0 °C.
Temperature Control Stability is defined as the standard deviation over 10 minutes, as measured by the saturation temperature control sensor after being at the point for 60 minutes.
Chamber Temperature Uniformity is defined as the maximum temperature difference between any two locations at a single point in time. Locations are within one inch of the chamber wall and 2.5 inches of the chamber door. Use a minimum chamber fan speed of 25% for a temperature range of -10 °C to 72 °C when using a fluid jacket door and ±10 °C from ambient when not.
Chamber pressure at 1 atmosphere, Uncertainty values represent an expanded uncertainty using a coverage factor, k=2, at an approximate level of confidence of 95%.
Uncertainty is not specified at temperatures below 0 °C or at flow rates below 10 L/min.
Uncertainty is based on the worst-case value from the 2900 uncertainty analysis.