Attachment_1_Purchase_Description_19M-203A-TE_Rev_3_dated_6_May_2019.pdf

PURCHASE DESCRIPTION

FOR

CHILLED MIRROR HYGROMETER

19M-203A-TE

6 May 2019

Rev3

1.0 Scope: The Chilled Mirror Hygrometer is a completely self-contained, portable bench top system with a temperature range of -80 to 20 °C to be used by the U.S . Air Force Primary Standards Laboratory (AFPSL) as a Check Standard in the calibration of Dew/Frost Point Meters for the Air Force. The system shall include a polished mirror free of any significant defects, a three- or four-stage thermoelectric heat pump known as a Peltier element, a cooling system to allow for low frost points without need for any external cooling device, light generator and receiver, and necessary electronics to allow the Chilled Mirror Hygrometer to operate as a complete system. The Chilled Mirror Hygrometer shall have the capability for the operator to measure dew or frost points by manually inputting or adjusting the parametric set points on a front panel keypad. The Chilled Mirror Hygrometer shall also have automatic capability to allow the technician to program all test parameters, initiate the calibration measurements, and leave the system to run unattended. It is replacing the MBW Elektronik model K-1806/DP30-SHSX III Dew Point Measuring System, which is now obsolete and can no longer be repaired. All calibrations will be accomplished in a controlled calibration laboratory environment.

2.0 Performance Requirements:

2.1 Dew/Frost Point Temperature Range: The minimum Dew/Frost Point Temperature range to be covered by the Chilled Mirror Hygrometer shall be -80 to 20 °C.

2.2 Dew/Frost Point Temperature Uncertainty: The Dew/Frost Point Temperature expanded uncertainty (k = 2) of the Chilled Mirror Hygrometer shall be ±0.1 °C or better over the complete Dew/Frost Point Temperature range stated above. This uncertainty value shall contain all components of error from all sources, such as measurement and control instrumentation and data acquisition errors. A complete uncertainty budget that includes all error components shall be provided.

2.3 Dew/Frost Point Repeatability: The Dew/Frost Point repeatability for the Chilled Mirror Hygrometer shall be ±0.05 °C.

2.4 Resolution: The Chilled Mirror Hygrometer shall have a minimum resolution of 0.01 °C for Dew and Frost Point and 0.1 % RH for Relative Humidity.

3.0 Functional Requirements:

3.1 Front Panel Display: The Chilled Mirror Hygrometer front panel display shall show all critical control and measurement parameters that are essential for operation. The display shall utilize easily-read fonts on a screen with high contrast between characters and background. Displayed numbers and letters shall be a minimum of 5 mm high.

3.2 Front Panel Operation: The Chilled Mirror Hygrometer shall have buttons on the front panel which shall provide manual access to all functions of the item.

3.3 Units: The Chilled Mirror Hygrometer shall, at a minimum, be able to monitor and display data in the following engineering units:

Dew/Frost Point - °C Temperature - °C

Relative Humidity - %RH Pressure - PSI Flowrate - SLPM

19M-203A-TE

6 May 2019

Rev3

3.4 Internal Pump: The Chilled Mirror Hygrometer shall have an internal pump for sampling gas from a humidity generator. Sample gas pressure and flow control settings shall be accomplished via the front panel. Pressure and flow rates shall be measured continuously. The sample gas flow rate shall have a range of at least 0.5 to 1 slpm.

3.5 Mirror Sensors: The Chilled Mirror Hygrometer shall contain both internal and remote dew and frost point measuring sensors. The performance requirements stated in section 2 shall apply to all sensors, and the mirror surface temperature shall be measured by a temperature sensor included with the mirror.

3.6 Mirror Status Indicator: The Chilled Mirror Hygrometer shall have a mechanism for continuously displaying the operating condition of the mirror to include how much light of the measuring-head lamp is reflected on the mirror and then transmitted, and formation of dew or frost on the mirror.

3.7 Mirror Contamination Compensation: The Chilled Mirror Hygrometer shall have a mechanism for compensation of any mirror contaminants present such that the performance requirements stated in section 2 are maintained. Both automated and manual capability for periodic removal of contamination shall be included.

3.8 Mirror Cleaning: The Chilled Mirror Hygrometer mirror shall be easily accessible for periodic cleaning by the operator.

3.9 Assurance of Frost Point at Temperatures Below O Degrees Celsius: · The Chilled Mirror Hygrometer shall have a mechanism to ensure the condensate at any temperature below O °C is solid ice only, i.e., the measured temperature of the mirror surface is truly frost point and not dew point.

3.10 High Dew Point Measurements: The Chilled Mirror Hygrometer shall have a mechanism to ensure no condensation of water vapor occurs within the sampling tubes, a problem that can occur at dew points above ambient room temperature.

3.11 Central Processing Unit (CPU): The Chilled Mirror Hygrometer shall be operated by an on-board, multifunctional CPU in conjunction with other peripheral cards to perform control and calculation functions. Dew and Frost points, sample gas pressure, and sample gas flowrates shall be capable of being inputted both manually by the operator via the front panel keyboard and automatically by way of a user customized setup program. Visual indications of system status shall be displayed in real time on the screen. The CPU shall have the capability of storing the calibration coefficients in a non-volatile memory for all sensors until the next calibration.

3.12 Firmware: Firmware for system control, data presentation and data acquisition and analysis for the Chilled Mirror Hygrometer shall be provided by the contractor. The firmware shall be capable of operating on the internal supplied CPU. The firmware shall include, at a minimum, the following features :

A display of real time measurements of humidity, dew and frost point temperature, pressure and flowrate.

• Automated control of user parameters to allow the unit to run unattended.

• Regulatory control of heating and cooling units.

19M-203A-TE

6 May 2019

Rev3

3.13 Communications: The Chilled Mirror Hygrometer shall also be capable of being connected to a WindowslO-based PC, furnished by the laboratory, for the purpose of downloading measurement results for data analysis. This connection shall be completed by means of a bi-directional RS232 or USB interface port.

3.14 Special Hardware/Software/License Requirements: Any special equipment, fixtures , tools, standards, etc. required for calibration and not common to a secondary calibration laboratory must be supplied with the Chilled Mirror Hygrometer. All calibration alignment/adjustments shall be accomplished by the operator, either manually or using automated alignment/adjustment software included with the Chilled Mirror Hygrometer. The software shall be licensed to the Air Force.

4.0 Physical/Mechanical Requirements:

4.1 Physical Dimensions and Weight: The Chilled Mirror Hygrometer shall have maximum outer dimensions of 610 mm wide by 457 mm deep by 508 mm high (24" wide by 18" deep by 20" high). The weight shall not exceed 110 pounds.

4.2 Operating Environment: The Chilled Mirror Hygrometer shall be capable of operating in an ambient temperature of 15 to 30 °C, non-condensing, without loss of performance or functional specifications stated elsewhere in this purchase description.

4.3 Power: The required power for the Chilled Mirror Hygrometer shall be 120 VRMS ±10%, 8 Amperes, and 60 Hz nominal. One or more detachable power cords with a minimum length of 8 feet (2 .2 meters) shall be provided with the Chilled Mirror Hygrometer.

4.4 Fuse: The Chilled Mirror Hygrometer shall include one or more fuses or circuit breaker(s) which shall disconnect the Chilled Mirror Hygrometer from the.power source in the event of excessive current that could damage the electronics package.

4.5 Warm-up Time: The Chilled Mirror Hygrometer shall meet all performance and functional requirements of this purchase description following a warm-up time of 30 minutes.

4.6 Individual Unique Identifier Designation: The Chilled Mirror Hygrometer shall be clearly labeled with a model number, serial number, and manufacturer' s name. Unique item identification labeling shall follow the Item Identification and Valuation clause as stated in the contract.

4. 7 Construction: The Chilled Mirror Hygrometer shall be designed and constructed of materials that meet the requirements of this specification and in accordance with the best commercial practices for industry-approved equipment. It shall be designed and manufactured to maximize reliability, maintainability, accuracy of operation, ease of operation and safety. All parts shall be able to withstand the conditions met in shipping, storage, installation, and service.

4.8 Air and Water Supply: Shop air and water, as needed, shall be provided by the calibration laboratory.

5.0 Acceptance Testing: The Chilled Mirror Hygrometer will be inspected and accepted at a destination specified elsewhere in this contract. The item will be checked with test equipment and parameters equal to or better than those required assuring specified performance requirements are met. Test equipment has first echelon certification directly traceable to the National Institute of Standards and Technology (NIST) or other AFMETCAL-approved source where required. Tests will be performed to assure the Chilled Mirror

19M-203A-TE

6 May 2019

Rev3

Hygrometer meets or exceeds all of the requirements of this purchase description. Such testing does not relieve the contractor of performing all inspections and quality control checks at the point of fabrication as necessary to assure performance as specified.

Attachment:

Data Requirements

Attachment to Purchase Description 19M-203A-TE

Chilled Mirror Hygrometer

DATA REQUIREMENTS

MANUALS: A complete user and service manual and calibration procedure shall be provided with each unit in contractor format. Manuals shall be on CD/DVD-ROM in Indexed Portable Document Format

(iPDF). The manuals shall comply with Data Item Description (DID) DI-TMSS-80527C and the Contract

Data Requirements List (DD Form 1423).