Gas Flow Standards
Contents
1. Test Calibration of Test Calibration of Thermal Mass Flow Controllers MFCs High Pressure Mass Flow Meters MFMs or MFCs 1 Host computer with RS 232 5 Device under test MFC 1 Host computer with RS 232 8 Regulator to protect molbox1 COM or IEEE 488 interface 6 Atmosphere or vacuum COM or IEEE 488 interface from overpressure 2 COMPASS for molbox 7 molbloc s 2 COMPASS for molbox 9 Flow adjusting valve calibration software calibration software if DUT does not control flow 3 molbox1 8 Regulator molstic 3 molbox1 or RFM 10 Device under test MFM 4 molbox1 MFC control option WOR supply 4 molbloc s with downstream or MFC cable 10 molstic molbloc mounting calibration 11 Pressure regulator to set system device under test upstream 5 Atmosphere pressure 6 Shut off valve 12 Gas suppl 7 Filter ppy PUTTING TOGETHER A SYSTEM moelbloe molbox Putting Together a System The heart of a molbloc molbox system is the molbox1 mass flow terminal The molbox performs the data acquisition and processing functions necessary to determine the flow through a molbloc flow element that is connected to it molbloc flow elements of varying flow path size To configure a molbloc molbox for your specific requirements follow the steps below 1 Select molbox or molbox RFM see pp 10 to 12 Choose molbox1 to e Minimize measurement uncertai2. COMPASS for molbox Main Run Screen GENERAL FEATURES standard and custom calibration reports All reference DUT and test data are collected and stored in standard delimited files that can be easily downloaded to other applications COMPASS is much more than a simple data acquisition and test sequencing tool It also includes specialized capabilities for data reduction in support of pressure and temperature dependent flow devices such as rotameters turbine meters and volume meters FROM A SIMPLE REFERENCE FLOW METER TOA COMPLETE CALIBRATION SYSTEM With a choice of two molbox models and a wide variety of accessories the exceptional flow measurement capabilities offered by molbloc molbox can be configured to fit a very wide variety of applications from a simple reference flow meter to a turnkey automated calibration system molbox RFM and a single molbloc configure a simple relatively low cost reference flow meter with measurement uncertainty of 0 5 of reading from 1 to 100 of full scale molbox1 with the MFC option molstics and COMPASS software make up a turnkey fully automated mass flow calibration bench COMPACT RUGGED AND TRANSPORTABLE molbloc molbox makes a very high performance mass flow standard easily transportable for the first time A molbox and one or several molblocs can safely be packaged and shipped or even hand carried from one location to another molbloc molbox can be used as an audit or
3. All specifications same as molbox1 unless specified otherwise 2 55 kg 5 6 Ib max 22 5 cm W x 8cmH x 20 cm D 8 9 in x 3 1 in x 7 9 in approx 2 x 550 kPa 80 psia piezoresistive silicon 12 5 kPa 1 8 psid piezoresistive silicon Not available Not available molkho MFC Control Option Analog Input Voltage Range 0 to 5 000 VDC Min Max Measurable Voltage 0 25 6 000 VDC Voltage Accuracy 0 05 FS Voltage Resolution 1 mVDC Current Range 4 to 20 mA Current Accuracy 0 05 FS Current Resolution 0 4 uA Valve Test Point Range 2 to 15 VDC in reference to 15 VDC Valve Test Point Accuracy 0 25 FS Valve Test Point Resolution 2 5 mVDC PRESSURE MEASUREMENT Type Oscillating quartz bellows Range FS Standard 0 to 550 kPa absolute 0 to 80 psia Microrange Option Not available Resolution Standard 0 7 Pa 0 0001 psi Microrange Option Not available Measurement Uncertainty One Year Absolute Pressure 0 02 FS Differential Mode with Tare 5 Pa 0 0007 psi 0 02 AP Microrange Option Not available melbox RFT Not available Piezoresistive silicon O to 12 5 kPa differential 1 8 psid 5 5 Pa 0 0008 psi 0 14 Pa 0 00002 psi 0 05 FS 20 Pa 0 003 psi 0 05 AP 0 5 Pa 0 0007 psi 0 05 AP E E TEMPERATURE MEASUREMENT molbloc PRTs with molbox Ohmic Measurement System Type Oscillating quartz crystal with mechanical bellow
4. SUPERIOR STABILITY OVER TIME The role of a transfer standard is to reliably transfer reference values from primary standards to other devices In filling this role the transfer standard s single most important characteristic is stability over time The stability over time of a molbloc molbox system is dependent on three parameters a the molbloc s laminar flow path geometry b the gas pressure measurement and c the gas temperature measurement The stability specification for a molbox1 based molbloc molbox system is 0 1 of reading per year This is made possible with a considerable safety margin by the fundamental mechanical stability of the molbloc flow Opath and pressure and temperature measurements that exceed the specification The molbloc s laminar flow path is the space between the molbloc body s central bore and the molbloc piston The path is defined using just two solid stainless steel parts In high range molblocs the piston is held rigidly in the cylinder by a patented holding system based on symmetrical elastic deformation of the centering holders In lower range molblocs in which the gap is quite small and even very small movement of the piston could alter the flow path significantly the piston is held by interference fit with the cylinder The flow path geometry is designed so that the gas passes straight through a simple shape minimizing opportunities for contaminants to collect All wetted surfaces are electrop
5. Transducer readings can be adjusted to agree with a calibration standard by setting simple calibration coefficients in the molbox Note The molbox RFM microrange option pressure transducer requires a O to 10 kPa 1 5 psi gauge calibration Calibration of the molblocs requires a flow standard with lower measurement uncertainty than that of the molbloc molbox system In the original factory calibration proprietary calibration coefficients which characterize the molbloc flow path are determined Since molblocs are static mechanical elements in which there is no inherent drift the original factory coefficients do not change unless the molbloc is damaged or contaminated For this reason molblocs that are found out of tolerance in recalibration are generally considered to need repair and are returned to DHI for service Special calibration software is available for facilities that require the capability to adjust molbloc readings to agree with their standards COMPASS FOR molbox CALIBRATION ASSISTANCE SOFTWARE COMPASS for molbox calibration assistance software takes molbloc molbox to the next step in automating calibrations COMPASS for molbox and a personal computer work with molbloc molbox to create a modern full function turnkey system for calibrating and testing flow devices COMPASS sets up device under test DUT records defines and associates test procedures with DUTs runs tests acquires reference and test data produces
6. x RFM molbox RFM features include Flow measurement uncertainty of 0 5 of reading Microrange option to reduce measurement uncertainty under 10 of molbloc full scale Micromachined silicon piezoresistive pressure transducers Very compact presentation Lower cost than molbox1 ORDERING INFORMATION Description molbox RFM Part Number FAM0005 STANDARD DELIVERY Each molbox RFM is delivered complete with Power cord Tilt up front feet molbloc to molbox pressure line with quick connectors 2 ea molbloc to molbox electrical connection cable 1 ea Utility software disc User s manual Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST Purpose OPTIONS Description Microrange option Part Number 02 Add 10 kPa 2 psi differential pressure transducer to improve resolution and lower uncertainty under 10 of molbloc full scale OPTIONAL ACCESSORIES Rack mount kit RPM3 molbox RFM P N 401465 Standard 19 in rack mount kit for molbox RFM Panel is 3 5 in 2U high molstics Gas handling hardware and mounting system for molblocs See molstic brochure COMPASS for molbox PC based calibration software to automate calibrations with molbloc molbox See COMPASS for molbox brochure CalTool for molbloc For calibration support of molblocs Allows molbloc calibrations to be adjusted by linear fit to agree with
7. 1 FS devices has a 5 1 or better measurement accuracy ratio with any device whose range is between 500 sccm and 5 slm With molbox RFM 0 5 of reading measurement uncertainty from 1 sccm to 10 slm can be achieved using only two molblocs molbloc molbox s rangeability reduces system complexity and original cost as well as on going recalibration costs Measurement Uncertainty 0 050 FS 0 020 FS 0 005 FS 0 005 FS 0 020 FS 100 0 050 FS molbox1 molbox RFM RFM Microrange molbloc Flow Measurement Uncertainty GENERAL FEATURES CONTINUOUS REAL TIME READING The mass flow through a laminar flow element at any moment in time is directly proportional to the pressure drop across the element Unlike systems based on rate of volume or rate of pressure change the measurement of flow through a laminar element is not time based This allows molbloc molbox to deliver flow readings as frequently as once per second with the system s full precision and minimum uncertainty Real time reading makes it possible to collect test or calibration data without having to wait for measurement cycles to complete or reset Real time reading provides instantaneous feedback on the effect of adjustments made to a device under test Real time reading also allows molbloc molbox to be used in active measurement applications such as blending reference gas mixes The laminar flow element s continuous uninte
8. check standard and as a field standard for on sight calibration or troubleshooting Its very high precision and stability also make it an ideal transfer standard for comparing primary standards at different locations molbox1 and molblocs Ready for Shipment molbloce molbox Typical System Configurations a 3 YY 3 gt q lt 4 On Line Verification of Test Calibration of Process Flow Measurement Control Rotameters or Turbine Flowmeters 1 molbox1 or RFM mobile or 4 Connection to atmosphere 1 Host computer with RS 232 6 Flow adjusting valve permanently installed gas collector or device COM or IEEE 488 interface 7 molbloc s P nder test 2 Host communications u 2 COMPASS for molbox 8 Regulator molstic optional 5 Connection to device under calibration software 3 molbloc mobile or test or gas supply 3 molbox1 or RFM i m woe t permanently installed molstic molbloc mounting upstream or downstream of 4 Atmosphere system device under test 5 Device under test e g rotameter or turbine meter 3 3
9. from less than 1 sccm to more than 100 slm with accuracy to 0 2 of reading in a variety of gases A 1 second update rate makes real time measurement and test instrument adjustment with a true flow standard possible for the first time Compact and readily transportable molbloc molbox can be operated locally from the full feature front panel or remotely over its RS232 and IEEE 488 interfaces molbloc molbox configurations and accessories support a wide variety of flow testing and measurement applications molbloc molbox can be integrated into systems for on line checking of process instruments easily transported for use as an on site audit or check standard and combined with accessories to set up a complete automated flow calibration bench molbloc molbox systems test and calibrate a wide variety of flow devices including thermal MFCs rotameters turbine meters bubble meters and others The pages that follow describe molbloc molbox GENERAL FEATURES Pages 3 to 7 describe molbloc molbox technology and summarize some of the important features that make molbloc molbox a unique flow calibration tool PUTTING TOGETHER A molbloc molbox SYSTEM Pages 8 and 9 illustrate some typical molbloc molbox configurations and provide instructions for putting together a molbloc molbox system to fit your specific needs molbox FLOW TERMINALS Pages 10 to 12 detail the two molbox flow terminal models available molbloc LAMINAR FLOW ELEMENTS Pag
10. Natural Resource Conservation Commision US EPA Redwood Microsystems Praxair Teledyne Brown Porter Instruments Unit Kinetics Qualiflow Mep caL Bio MEDICAL Datex Ohmeda Edstrom Industries Genzyme NATIONAL LNE France NIST USA PECO Energy Pennsylvania Power amp Light Public Service Electric amp Gas St Jude Medical SmithKline Beecham Westaim Biomedical Johnson amp Johnson Merck Protein Design Labs MEASUREMENT LABORATORIES NRC Canada OFMET Switzerland PTB Germany NUCLEAR POWER Niagara Mohawk TU Electric Virginia Power PETROCHEMICAL R amp D Dow Chemical Ethyl Petrol Add Rohm amp Haas Union Carbide Instituto Mexicano de Petroleos itives Mobil SEMICONDUCTOR MICROELECTRONICS FIBER OPTICS Advanced Micro Devices Alcatel Allegro Microsystems Analog Devices Applied Materials Atmel Aerometrologie Babcock and Wilcox Bechtel Nevada Brigham Young Univ Concoa Represented Locally By DH Instruments Inc 1905 W 3rd St Tempe AZ 85281 2490 USA Tel 480 967 1555 Fax 480 968 3574 dhi dhinstruments com www dhinstruments com 1999 DH Instruments Inc Cherry Semiconductor Cirrent Corning Eastman Kodak Epitaxx IBM Gelman Sciences General Motors Honeywell Micr Horiba Intertechnique Intel Philips Intersil SGS Thompson Lucent Spectran Mitel 3M Motorola Varian National Semiconductor OTHER Laminar Technologies Peus L
11. RMATION Description molbox1 Part Number FAM0004 STANDARD DELIVERY Each molbox1 is delivered complete with Power cord Tilt up front feet molbloc to molbox pressure line with quick connectors 4 ea molbloc to molbox electrical connection cable 2 ea Rubber feet caps 4 ea Utility software disc User s manual Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST molbox FLOW TERMINALS drive external valves or other accessories Rear panel connector supplied OPTIONAL ACCESSORIES Rack mount kit molbox1 P N 401154 Standard 19 in rack mount kit for molbox1 Panel is 5 25 in 3U high MFC Switchbox Supply power to 5 MFCs simultaneously and switch molbox1 MFC control option between five channels See MFC Switchbox brochure molstics Gas handling hardware and mounting system for molblocs See molstic brochure COMPASS for molbox PC based calibration software to automate calibrations with molbloc molbox See COMPASS for molbox brochure CalTool for molbloc PC based software for calibration support of molblocs Allows molbloc calibrations to be adjusted by linear fit to agree with another flow standard with a given gas at a given operating pressure Training A three day training course for molbloc molbox operation is conducted regularly at the DH Instruments Inc Arizona facility On site training can also be arranged molbheo
12. a TM molbloc molbo x Gas Fiow standards DH P Calibration Snlulionk for Pressure and Flow molbloe molbo M Flow Calibration System TABLE OF CONTENTS INTRODUCTION GENERAL FEATURES 3 PUTTING TOGETHER 8 A molbloc molbox FLOW CALIBRATION SYSTEM molbox FLOW TERMINALS molbloc LAMINAR 13 FLOW ELEMENTS SPECIFICATIONS 17 TABLE OF CONTENTS amp INTRODUCTION INTRODUCTION In the early 1990s DHI recognized the growing need for a new calibration tool for low gas flows To support increasing requirements for lower measurement uncertainties and documented traceability of flow measurements at the process level a transfer standard combining high performance with portability and ease of use was needed DHI developed the molbloc molbox flow calibration system in response to this need Based on a new patented laminar flow element design and applying today s modern measuring mathematical modeling data processing and manufacturing techniques molbloc molbox introduced a new level of performance and convenience in low flow standards molbloc molbox has rapidly gained wide acceptance in a variety of fields semiconductors fiber optics pharmaceuticals environmental monitoring energy production reference gas blending research and standards laboratories as the reference of choice in assuring the integrity of low flow measurements molbloc molbox covers the flow range
13. ability before ordering Special N2 Calibration Full Mod Hi P 600204 Special N2 Calibration Downstream gt 5E1 molbloc 600206 Special N2 Calibration Downstream 1E1 5E1 molbloc 600205 Special Gas Calibration Full Mod Lo P 1E1 5E1 molbloc 600202 specify gas Special Gas Calibration Full Mod Lo P gt 5E1 molbloc 600201 specify gas Special Gas Calibration Full Mod Hi P 1E1 5E1 molbloc 600207 specify gas Special Gas Calibration Full Mod Hi P gt 5E1 molbloc 600208 specify gas Specia ibration Downstream 1E1 5E1 molbloc 600209 specify gas Special Gas Calibration Downstream gt 5E1 molbloc 600210 specify gas Special Gas Calibration Single P 1E1 5E1 molbloc specify 600211 gas and single pressure value between 250 and 525 kPa absolute Special Gas Calibration Single P gt 5E1 molbloc specify gas 600212 and single pressure value between 250 and 525 kPa absolute molbloc LAMINAR FLOW ELEMENTS 14 molbloc RANGES WITH LOW PRESSURE CALIBRATIONS e FULL MOD LOW PRESSURE e DOWNSTREAM e SINGLE P LOW PRESSURE molbloc SIZE AND FULL SCALE FLOW sccm SIZE SIZE SIZE SIZE SIZE SIZE SIZE 5E1 1E2 2E2 5E2 1E3 5E3 1E4 Nitrogen Argon Helium Sulfur Hexafluoride Xenon Butane Ethane Ethylene Hydrogen FLAMMABLE Methane Propane Carbon Tetrafluoride Hexafluoroethene Trifluoromethane FLUORO CARBONS Air Carbon Dioxid
14. another flow standard with a given gas at a given operating pressure Training A three day training course for molbloc molbox operation is conducted regularly at the DH Instruments Inc Arizona facility On site training can also be arranged molbox FLOW TERMINALS 12 13 molblog Laminar Flow Elements molblocs are laminar flow elements for use with molbox mass flow terminals The molbloc flow path is the longitudinal annular gap between a piston and a close fitting cylindrical bore in the molbloc body Different molbloc ranges are obtained by varying piston diameters within the same body to vary the size of the annular gap For high flow ranges size 1E4 and above a larger molbloc body with a larger cylindrical bore is used The molbloc piston is held in place by the symmetrical elastic deformation of piston holders and for smaller annular gaps by interference fit of the piston in the cylinder Quick connectors are used to connect the molbloc s upstream and downstream pressure stabilization chambers to the molbox pressure lines Two platinum resistance thermometers PRT are embedded symmetrically in the molbloc body to measure its average temperature The molbloc is equipped with an EEPROM to store molbloc and PRT calibration coefficients The EEPROM information along with the resistance of the PRTs is read over the molbox 15 pin data cable connection All wetted molbloc surfaces are electroplished t
15. brations are a lower cost alternative to full mod calibrations for non N gases for cases in which the molbloc downstream pressures will be elevated above atmosphere Single P calibrations require that the molbloc always be used around the same pressure for that gas CALIBRATION TYPE Full mod low pressure Full mod high pressure Downstream Single P low pressure non N2 gases only Single P high pressure non N2 gases only OPERATING PRESSURE 250 to 325 kPa absolute 36 to 48 psia upstream of molbloc 325 to 525 kPa absolute 48 to 76 psia upstream of molbloc Atmospheric pressure downstream of molbloc Any specified single molbloc upstream pressure between 250 and 325 kPa absolute 36 to 48 psia Any specified single molbloc upstream pressure NOMINAL DIFFERENTIAL PRESSURE AT MAX FLOW 50 kPa 7 5 psi 50 kPa 7 5 psi 80 kPa 12 psi 50 kPa 7 5 psi 50 kPa 7 5 psi between 325 and 525 kPa absolute 48 to 76 psia Operating pressure values are absolute For approximate gauge pressure values subtract typical atmospheric pressure SPECIAL GAS CALIBRATIONS Standard molblocs include a Nitrogen N full mod low pressure calibration A different N calibration and or calibration with gases other than N must be ordered as separate line items The DHI mass flow calibration facility does not support calibration of all gases for all ranges Please verify avail
16. displays including Average Rate Hi Lo Totalize Second Flow Unit Deviation Freeze Clean H Gi F E E Resolution Function Adjust the resolution of the measured flow display F molbloc Function View current molbloc identification initialize a newly connected molbloc G Pressure amp Temperature Function Display real time molbloc pressure and temperature measurements and the Reynolds number of the current flow H Valving Functions Access automated pressure tare leak checking and gas purging functions molbox FLOW TERMINALS 10 molba OPTIONS Description molbox1 Option 009 MFC control option Part Number 03 Purpose molbox1 features include e Flow measurement uncertainty of 0 2 of reading e Very high performance quartz crystal oscillator based pressure transducers Set and read analog voltage and Two molbloc channels allowing two molblocs to be connected simultaneously and measurements to be switched between them using the A_B function Also supports A B and A B measurement current MFCs Optional board is built in to molbox1 and connector is on rear panel Delivered with MFC cable and connection kit Description molbox1 Option 012 drivers option Part Number 04 Provide 8 on off 12 VDC signals to e Integrated analog MFC measurement and control option with switchbox for multiple channels e Valve driver option 8 switchable 12V outputs Purpose 11 ORDERING INFO
17. e Carbon Monoxide Nitrous Oxide Oxygen TOP VIEW FRONT VIEW M4 X 0 7 Thread 7 00 0 276 Deep 2 PI 58 50 2 303 74 50 2 933 16 00 0 630 24 00 0 945 32 00 1 260 SQ 48 00 1 890 SQ 68 84 2 750 80 00 3 150 19 06 0 750 28 00 1 102 124 00 4 881 157 00 6 181 i BOTTOM VIEW molbloc Dimensions mm in molbloc LAMINAR FLOW ELEMENTS molbloc RANGES WITH HIGH PRESSURE CALIBRATIONS e FULL MOD HIGH PRESSURE SINGLE P HIGH PRESSURE molbloc SIZE AND FULL SCALE FLOW sccm SIZE SIZE SIZE SIZE SIZE SIZE SIZE 5E1 1E2 2E2 5E2 1E3 5E3 1E4 Nitrogen Argon Helium Sulfur Hexafluoride Xenon Butane Ethane 20 000 13 800 Ethylene 22 000 12 700 Hydrogen 130 000 Ww mr a lt lt m Te Methane 42 000 12 000 Propane Carbon Tetrafluoride Hexafluoroethene Trifluoromethane FLUORO CARBONS Air Carbon Dioxide Carbon Monoxide Oxygen Nitrous Oxide molbloc RANGES TABLES LEGEND A bold value indicates that the maximum flow is limited by the maximum Reynolds Where there is no value in the table this indicates that the maximum Reynolds number value of 1 200 which is reached before the normal differential pressure range number is reached before the differential pressures reaches 5 kPa therefore is reached In that case the second value gives the minimum flow f
18. ed range of 550 kPa 80 psia Oscillating quartz crystal with mechanical bellows Not applicable Pressure Connections molbox and molbloc Quick connectors equivalent to Swagelok QM Series QM2 B200 Flow Connections molbloc Pressure Limits Max Working Pressure Max Pressure W Out Damage 1 4 in VCR 550 kPa absolute 80 psia 800 kPa absolute 115 psia Ohmic Measurement System Resolution Measurement Uncertainty Accuracy of 100 Q and 110 Q Reference Resistors Stability of 100 Q and 110 Q Reference Resistors Gases Supported 11 99 Flow Ranges CE Conformance Valve Driver Option 0 004 Q 0 02 of reading 0 01 0 005 per three years Nitrogen N3 Air Argon Ar Butane C4H 49 Carbon Monoxide CO Helium He Oxygen O3 Carbon Dioxide CO Carbon Tetrafluoride CF 4 Ethane C Hg Ethylene C H Fluoroform CHF3 Hexafluoroethane CF Hydrogen H3 Methane CH4 Nitrous Oxide N20 Propane C3Hg Sulfur Hexafluoride SFe Xenon Xe O 10 sccm to 0 100 slm see molbloc Ranges Tables pages 15 and 16 Available must be specified 8 12 V outputs Each output can sink 500 mA at 12 V max 1 Amp total MFC Control Option Analog Output Voltage Range 17 Voltage Accuracy Voltage Resolution Current Range Current Accuracy Current Resolution SPECIFICATIONS 0 to 6 000 VDC 0 7 S 0 1 mVDC 4 to 20 mA HOOS 0 4 uA melbox RFM
19. enance Manual LabVIEW drivers are available at no charge as program building blocks for National Instruments LabVIEW users TRACEABLE ACCURACY SUPPORTED BY PRIMARY GRAVIMETRIC STANDARDS molbloc molbox has the precision and stability over time required to be an excellent transfer standard To meet its full potential as a calibration tool it must be calibrated with primary standards traceable to national and international standards molbloc molbox s continuous reading capability and very high stability over time allow it to be calibrated using the only method that derives mass flow directly from the base units of mass and time In this method called gravimetric the amount of gas flowed over a period of time is weighed so its mass is known directly with no dependence on the imperfect knowledge of the gas s thermodynamic properties With the gravimetric method in exact agreement with the definition of a primary standard the uncertainty on mass flow is dependent only on the direct measurement of the base units of mass and time from which mass flow is derived DHI has developed a complete gravimetric calibration facility dedicated to molbloc molbox calibration The calibration system is maintained by the DHI metrology service and documented in a formal quality assurance program with a detailed uncertainty analysis To further increase confidence and guarantee homogeneity of measurements flow intercomparisons are regularly per
20. erforms the functions listed below For maximum versatility two different molbox models are available molbox1 and molbox RFM Both use the e molbloc Pressure and Temperature Measurement The molbloc pressure ports are connected by flexible lines with quick connectors to the molbox s pressure transducers A data cable connects the molbloc platinum resistance thermometers to the molbox s ohmic measurement system and allows the molbox to read the molbloc EEPROM e Pressure Valving System Miniature valves inside the molbox support routines to zero the molbox pressure transducers run automated leak checks and purge when changing gases e Calculation of the Mass Flow Through the molbloc The molbox reads molbloc specific calibration coefficients off the molbloc s EEPROM The complete thermodynamic characteristics of the molbox supported gases are stored in molbox s non volatile memory Embedded software uses current pressure and temperature measurements the characteristics of the flowing gas and molbloc calibration coefficients to molbox RFM REFERENCE FLOW MONITTRS same molblocs but provide different measurement uncertainties size and cost Generally molbox1 is oriented towards applications in which minimizing measurement uncertainty and stability over time are the most important requirements molbox RFM has slightly lower performance but is also lower in cost and more compact execute the molbloc mass flow equation and p
21. es 13 to 16 cover the molbloc flow elements and calibration options available to cover different flow ranges with different gases and pressure requirements SPECIFICATIONS Pages 17 and 18 list complete molbloc molbox technical specifications Though you ll find this catalog goes well beyond traditional commercial literature in its efforts to inform you everything about molbloc molbox and how it can benefit your flow measurements cannot be included here For additional molbloc molbox assistance or information on DHI s other flow and pressure calibration products and services please contact DHI or your local representative You can count on our commitment to objectively analyze your needs and recommend the best solutions to meet them Th malbloac Laminar Flow Element sharp PaM Pipa zent Ret Determined by P T Py Zann T hen See p 16 for List of Symbols Known doom Gas Propertias a F tip Beteomined drain Gravimetric Calioralion Ca INTRODUCTION molbloe molbo M General Features FOUNDED ON PROVEN LAWS OF GAS BEHAVIOR The molbloc molbox flow measurement principle follows established laminar flow theory In accordance with well known laws of gas behavior the flow of a known gas in the laminar flow regime can be calculated from the flow path geometry and the gas pressure and temperature see molbloc flow equation on previous page Parabolic Gas Velocity Distribution in La
22. formed with a variety of primary methods in other mass flow metrology laboratories The DHI calibration system is used to calibrate every molbloc and each one is delivered with a complete calibration report documenting traceability to the United States National Institute of Standards and Technology NIST and including specific measurement results a Gravimetric Calibration RECALIBRATION OPTIONS The recommended recalibration interval for a molbloc molbox system is one year The one year interval is not a reflection of the intrinsic stability of the system which without incident should hold its specifications much longer One year is recommended as a precaution considering variations in conditions of use from application to application and the central role that molbloc molbox usually plays in the user s flow measurement system After the first two annual recalibrations an analysis of the results may justify extending recalibration interval There are two aspects to recalibrating a molbloc molbox system One is the calibration of the pressure transducers in the molbox the other is the verification of the stability of the laminar flow path of the molbloc These can be conducted independently one from the other GENERAL FEATURES Calibration of the molbox pressure transducers is a routine procedure for any facility with high accuracy pressure calibration capability in the range of atmosphere to 550 kPa absolute 80 psia
23. itton Life Support Pratt amp Whitney oswitch Lockheed Martin Raytheon NASA US Army North Coast Calibration US Airforce Due to a policy of continuous improvement all specifications contained in this brochure are subject to change without notice Products described herein are protected by US and international patents and patents pending molbloc molbox molstic and molbox RFM are trademarks of DH Instruments Inc COMPASS is a registered trademark of DH Instruments Inc LabVIEW is a registered trademark of National Instruments Corporation Swagelok and VCR are registered trademarks of the Swagelok Company Viton is a registered trademark of DuPont Company In Europe CalTechnix S A 120 av Charles de Gaulle 92200 Neuilly sur Seine FRANCE Tel 1 46 40 37 70 Fax 1 46 40 37 71 caltechnix compuserve com www caltechnix com www dhinstruments com Printed in USA Bro No 9901 1 B 10
24. m Pressure F Pa Upstream Pressure 7 lt Purge Time Remaining molbox Purging Function Display Also included are advanced functions such as e Averaging over time with adjustable time period and standard deviation calculation e Hi Lo monitoring e Flow totalizing with adjustable time period e Simultaneous display in two different flow units of measure e MFC control and measurement with flow and FS conversions molbox1 option only e Password protected data security Current Flowing Flow Rate gt Gas ra Jord Total Flow Flow Time Flow Totalizer Function Display As molbox s embedded software is stored in FLASH memory keeping molbox current with all the latest features is easy and cost free Periodic software improvements and upgrades are placed on DHI s world wide web site www dhinstruments com and can be downloaded and installed by the user at no charge STANDARD COMMUNICATIONS INTERFACES Every molbox includes RS232 and IEEE 488 interfaces for communication with a host computer A second RS232 port COM2 is included for pass through communication with another RS232 device TEEE 488 Rear Panel Interface Connections The interfaces are supported by a complete set of ASCII command strings allowing all molbox measurements and functions to be accessed remotely All aspects of interfacing protocol and commands are thoroughly documented in the molbox Operation and Maint
25. minar Flow molbloc molbox achieves unprecedented levels of stability and precision from the laminar flow principle by applying today s modern sensor mathematical modeling and data processing technologies to a flow element design so novel it has been granted US and international patent protection This combination improves knowledge of gas pressure and temperature provides a better definition of flow path and allows comprehensive real time flow calculation using the thermodynamic properties of the gas under actual flowing conditions ADVANCED PRESSURE AND TEMPERATURE MEASUREMENT TECHNOLOGY The uncertainty in flow measurements based on the laminar flow principle is very highly dependent on differential pressure gas density and viscosity and therefore the uncertainty in the pressure and temperature of the flowing gas molbloc molbox breaks new ground in gas pressure and temperature measurement The pressure of the gas upstream P1 and downstream P2 of the molbloc flow element is picked off from pressure stabilization chambers and measured by two absolute pressure transducers GENERAL FEATURES located in the molbox flow terminal In molbox1 the transducers employ state of the art crystal oscillator technology providing 1 ppm resolution and 0 01 per year stability The upstream and downstream transducer readings are averaged to determine the absolute gas pressure The difference between the two pressure readings provides
26. nty molbox1 uses premium pressure transducers to provide the lowest measurement uncertainty and best stability over time Set and read analog mass flow controllers MFCs with the molbox molbox1 offers an integrated analog MFC control option which sets and reads 0 to 5 V and 4 to 20 mA MICs e Support two molbloc channels Choose molbox RFM to e Reduce system cost e Minimize molbox size e Minimize the number of molblocs needed to cover your range with the microrange option e If you do not need the molbox to set and read analog MFCs 2 Select the molbloc Mass Flow Elements see pp 13 to 16 This includes selecting the molbloc pressure dependent calibration type s sizes and special gas calibrations if needed a Select one of the three pressure dependent calibration types see p 14 Determine the pressure at which the molbloc must be operated depending on whether it will be upstream or downstream of the device under test PUTTING TOGETHER A SYSTEM are available to cover different flow ranges molstic mounting systems are offered as an off the shelf solution to put the molblocs into service and connect to a device to be tested COMPASS application software is available to complete a fully automated test system DUT and considering the molbloc and DUT differential pressure requirements b Select the molbloc size s see tables on pp 15 and 16 A molbloc s flow range varies with the molbl
27. o a 0 15 u Ra to avoid contaminant accumulation in the flow path and molblocs are assembled under a class 100 clean hood molbloc Cutaway molbloc RANGES molblocs sizes are designated by a number relative to their nominal flow impedance The nominal impedance results in nominal flow ranges when flowing nitrogen gas with 250 kPa absolute 36 psia upstream pressure and 50 kPa 7 5 psid differential pressure across the molbloc In practice the molbloc flow range may be quite different from the nominal flow range The difference comes from differences in density and viscosity between gases and from different molbloc operating pressure calibration options Available molbloc sizes and ranges with various gases by calibration type are listed in the molbloc Ranges tables see pp 15 and 16 molbloc PRESSURE DEPENDENT CALIBRATION TYPES Different pressure dependent molbloc calibration options are offered to accommodate the operating pressure requirements of different applications The options are outlined in the molbloc Pressure Dependent Calibration Types table see p 14 Small molbloc in Case 5E3 and Lower Large molbloc in Case 1E4 and Higher See pp 17 and 18 for complete molbloc molbox flow measurement specifications molbloc LAMINAR FLOW ELEMENTS ORDERING INFORMATION STANDARD DELIVERY Each molbloc is delivered complete with e Storage and shipping case e Soft reusable VCR O rings and moun
28. oc s size pressure dependent calibration type and the gas flowed Note that all molblocs measure flow from zero to full scale and their measurement uncertainty is a percent of reading above 10 full scale 1 for molbox RFM with the microrange option c Select the molbloc special gas calibrations All molblocs are calibrated with nitrogen N but can measure the flow of any molbox supported gas With non N gases for lowest measurement uncertainty and documented traceability a Calibration with the gas must be specified 3 Select One or Several molstic molbloc Mounting Systems see molstic brochure If Needed molstics provide an engineered solution to the practical issues of connecting the molbloc to a regulated gas supply mounting the molbloc and mounting and connecting to a device under test 4 Select molbloc molbox Applications Software If Needed e COMPASS for molbox see COMPASS brochure COMPASS for molbox software works with molbloc molbox to create a turnkey full function automated system for calibrating and testing a wide variety of flow measuring and controlling devices e CalTool for molbloc see CalTool brochure CalTool for molbloc software supports single P type see p 14 user recalibration of molblocs The molbloc can be adjusted to agree with another flow standard at a specific pressure TM Flow Terminals The molbox is the center of a molbloc molbox flow calibration system The molbox p
29. olished to a 0 15 u Ra finish to avoid particle collection from the flowing gas Every molbox has identical upstream and downstream pressure transducers In molbox1 these provide stability of 0 01 per year Each time the pressure transducers are zeroed differentially they are also compared one to the other and the user is alerted to disagreements that may indicate excessive drift The platinum resistance thermometers PRTs that measure molbloc temperature are read by the molbox s ohmic measurement system At each molbox power up an automated routine calibrates the ohmic measurement system against on board reference resistors with three year stability of 0 005 This combination provides temperature reading stability of better than 0 01 per year Asa precaution against damage or malfunction the temperature readings of the two PRTs are also regularly compared to each other to identify excessive disagreements OUTSTANDING RANGEABILITY molbloc molbox s very high rangeability makes it particularly effective when configuring a system to cover a wide range of devices to be calibrated molbloc molbox s flow measurement uncertainty is relative to the flow reading not the molbloc full scale Since the typical device to be calibrated has measurement uncertainty that is relative to its full scale one range of molbloc can be used to calibrate a wide range of devices For example a 5 slm molbloc used with molbox1 to calibrate
30. or which calibration with that gas is not useful measurement uncertainty is 0 2 0 5 with molbox RFM of reading With the N A The operating pressure range is greater than the vapor pressure value for molbox RFM microrange option this value is divided by 10 With molbox1 on size 3E4 this gas the 0 2 is 0 3 LIST OF SYMBOLS molbloc LAMINAR FLOW ELEMENT P 2 mass flow kg s Cg geometry of molbloc flow path and m3 upstream absolute pressure Pa Reynolds number dependence Reynolds number L downstream absolute pressure Pa molecular weight of the gas g mol 16 P P3 a Pa compressibility factor of the gas under P T conditions universal gas constant a absolute temperature of gas k dynamic gas viscosity under P T conditions Paes radius of the piston m molbloc LAMINAR FLOW ELEMENTS molbloe molbo GENERAL Power Requirements Normal Operating Temperature Range Storage Temperature Range Vibration Weight Dimensions Microprocessor Communication Ports M Specifications 85 to 264 VAC 47 to 440 Hz 18 VA max consumption 15 to 35 C 20 to 70 C Meets MIL T 28800D 6 8 kg 15 Ib max 32 cm W X 12 cm H X 30 cm D 12 6 in X 4 7 in X 11 8 in approx Motorola 68302 16 MHz RS 232 COM1 RS 232 COM2 IEEE 488 2 Reference Pressure Transducers RPTs Standard Microrange Option 2 x 700 kPa 100 psia with calibrat
31. rated Standard 0 2 of reading 0 02 FS under 10 FS 3E4 molbloc 0 3 of reading 0 03 FS under 10 FS Microrange Option Not available all ranges Precision Combined linearity hysteresis repeatability Stability Maximum change in zero and span over specified time period for typical molbox and molbloc used under typical conditions As stability can only be predicted stability for a specific molbox and molbloc should be established from experience 0 5 of reading 0 05 FS under 10 FS 0 5 of reading 0 05 FS under 10 FS 18 0 5 of reading from 1 to 10 FS 0 05 FS under 1 FS 3 Measurement Uncertainty Maximum deviation of the molbox flow indication from the true value of the flow through the molbloc including precision stability and DHI calibration standard accuracy Measurement uncertainty is sometimes referred to as accuracy SPECIFICATIONS moalbloc molbhex SOME USERS WORLDWIDE Allegheny County Health Dept Indiana Dept of Environmental Management Aera Air Liquide Brooks Instruments Abott Boston Scientific Scimed Datascope CMI Czech Republic CMS Taiwan American Electric Power Baltimore Gas amp Electric Detroit Edison Amoco Arco Chemical ENVIRONMENTAL QUALITY MONITORING Dade County Division of Florida DEP Environmental Resource Pennsylvania DEP Management Gas DELIVERY SPECIALTY GASES Millipore Pneutronics TX
32. rovide real time mass flow measurements e Local Operator Interface A 4 x 4 keypad and 2 x 20 display provide local user control over molbox operation allowing a wide variety of functions to be performed e Remote Interfaces RS232 and IEEE 488 interfaces support host computer communications using simple ASCII string commands A second RS232 interface COM2 is available for pass through communications to another device e Advanced Measurement Functions molboxes support advanced measurement functions such as averaging flow totalizing hi lo and others e Analog MFC Support molbox1 only An optional board with rear panel connector sets and reads both voltage and current in support of analog mass flow controller MFC testing A B C D 4 1 Ready Not Ready indication based on user defined stability test 2 Current rate of flow through the molbloc and unit of measure 3 Gas currently flowing 4 Special functions display line select Average Rate Hi Lo Totalize Second Flow Unit Deviation Freeze or Clean K Function Set the device under test DUT gas conversion factor if applicable GAS Function Select the gas being flowed more than 18 gases supported UNIT Function Select the mass flow unit of measure with adjustable reference temperature for volumetrically based mass flow units and adjustable pressure and temperature for volume flow units Displays Function Select special advanced function
33. rrupted reading capability makes it the ideal standard for checking or calibrating flow totalizing devices molbloc molbox can measure total flow without interruption over any time period MULTIPLE GAS SUPPORT molbloc molbox can measure the flow of a wide variety of gases These include the common inert gases as well as a variety of industrial process and calibration surrogate gases The complete thermodynamic properties unique to each gas are stored in molbox non volatile memory These are recalled and applied when the gas is selected The gas selection can be made directly at any time from the molbox front panel or by remote command An automated purge function clears the old gas from the molbox pneumatic circuit when using a new gas ADVANCED ON BOARD FUNCTIONS To complement its basic flow measuring capability and maximize the system s utility molbox supports a wide range of functions and special features These include operational features such as e Measure and display in 28 different units of mass and volume flow including user define units e Select from more than 18 different gases GENERAL FEATURES e Real time molbloc pressure and temperature displays e Adjustable display resolution e Full time stability dependent ready not ready indication e Automated purge routine for changing gases e Intelligent internal and external leak detection routines e Overpressure monitoring and self defense system Downstrea
34. s Digiquartz Range FS 0 to 40 C Resolution 0 01 C Measurement Uncertainty 0 05 C On Board Piezoresistive silicon Reference Resistor 100 and 110 Q 0 01 stability better than 25 ppm year FLOW MEASUREMENT Measurement Update Rate 1 second Range 0 to molbloc full scale depending on molbloc designation gas and molbloc pressure dependent calibration type see molbloc Ranges Tables pp 15 and 16 Resolution 0 0015 FS 0 01 FS Linearity Standard 0 15 of reading 0 015 FS under 10 FS 0 23 of reading 0 023 FS under 10 FS Microrange Option Not available Repeatability 0 23 of reading from 1 to 10 FS 0 023 FS under 1 FS Standard 0 05 of reading 0 05 FS under 10 FS 0 1 of reading 0 01 FS under 10 FS Microrange Option Not available Precision 0 1 of reading from 1 to 10 FS 0 01 FS under 1 FS Standard 0 16 of reading 0 016 FS under 10 FS 0 25 of reading 0 025 FS under 10 FS Microrange Option Not available Predicted Stability2 One Year Standard 0 1 of reading 0 01 FS under 10 FS Microrange Option Not available 0 25 of reading from 1 to 10 FS 0 025 FS under 1 FS 0 15 of reading 0 015 FS under 10 FS 0 15 of reading from 1 to 10 FS 0 015 FS under 1 FS Measurement Uncertainty N and Any molbox Supported Gas for Which the molbloc in Use is Calib
35. the Embedded PRT _ Gas Entering molbloc Gas at molbloc Temperature molbloc Gas Pressure and Temperature Measurement differential pressure across the molbloc Internal molbox valving and an automated tare function allow the two transducers differential measurement to be autozeroed at any time independently of current flow conditions A patented design greatly improves the determination of the temperature of the gas flowing through the molbloc flow element Rather than attempting to measure the temperature of the gas entering or exiting the flow element with a probe the gas is forced to the temperature of the molbloc body and the molbloc body temperature is measured The large thermal mass of the molbloc body and the very large metal to gas contact surface created by molbloc s annular flow path cause the gas to take on the molbloc s temperature An isothermal gas expansion occurs as gas flows through the molbloc The temperature of the isotherm is determined by measuring the molbloc body temperature The molbloc body temperature is measured very precisely using two platinum resistance thermometers PRT embedded symmetrically in the molbloc body The PRTs are read by an ohmic measurement system in the molbox that self calibrates with on board reference resistors This combination allows the temperature of the gas flowing through the molbloc to be known within better than 0 1 C
36. ting instructions e Full mod low pressure Nitrogen N3 calibration A different N calibration and or calibration with non N gases must be ordered as separate line item e Calibration report documenting traceability to the United States National Institute of Standards and Technology NIST and reporting measured calibration data molbloc MASS FLOW ELEMENTS molbloc mass flow elements are ordered by size designation and part number see table El VCR V Q 401182 5E1 VCR V Q 401183 401184 401187 401198 400842 400483 401080 401042 E2 VCR V Q 2E2 VCR V Q 5E2 VCR V Q E3 VCR V Q 5E3 VCR V Q E4 VCR V Q 3E4 VCR V Q FS BS FO BS FO FC FS Fo molbloc PRESSURE DEPENDENT CALIBRATION TYPES To accommodate different requirements different operating pressure calibration options are available for molbloc Every molbloc has an N full mod calibration e Full mod low or high pressure calibrations are for cases in which the molbloc downstream and upstream pressures will be elevated above atmosphere usually the case if the device under test is downstream of molbloc The upstream molbloc pressure may vary within a range Two ranges are available high and low pressure e Downstream calibrations are for cases in which the molbloc downstream pressure is atmophsperic pressure usually the case if the device under test is upstream of the molbloc Single P low or high pressure cali
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