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Miscellaneous Publications
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The Changing Market for Gas Flowmeter Calibration Services  Download PDF
Tom Kegel,
8/24/2005, CIATEQ
Abstract:
In 1965 The Colorado Engineering Experiment Station established a calibration facility in a surplus Atlas E missile site in the high plains of eastern Colorado. The first two decades of operation served the aerospace community in meeting goals of sending mankind into space and providing for the national defense. During these years a flow community developed that advanced the state of the art in compressible flow measurement. While the flow of many fluids were measured in many industries, the aerospace industry dominated the market. In more recent times diminishing government expenditures and international events have reduced the size of the aerospace industry. Meanwhile, the increasing cost of energy has highlighted the need for reduced uncertainty in the measurement of natural gas. These events have shifted the dominance in the calibration market away from aerospace to the natural gas sector of the energy business. This paper explores several effects that this fundamental shift has made on the calibration business. Natural gas is often measured to transfer custody from a buyer to a seller, the meter is the “cash register” for the gas company. While always important, the flow measurement is much closer to the core business in the gas industry than was ever the case in the aerospace industry. The calibration process is therefore under much closer scrutiny. The measurement technology is advancing. The orifice plate is an older technology that enables measurement without calibration; the newer technologies require calibration. As a result, the broad understanding of flow calibration and measurement uncertainty is still evolving. The involvement of governments in measurement issues varies around the world. The calibration business changes with that role. In the United States the details of the measurement are stipulated in the sales contract while in Europe they are subject to government regulation. In many developing countries, the energy business is nationalized and closed to competition. As the natural gas businesss becomes more global, the focus of calibration providers must shift from local to global.
Measurement Assurance Program of the CEESIowa Calibration Facility Download PDF
Tom Kegel,
3/9/2004, 3rd International South East Asia Hydrocarbon Flow Measurement Workshop
Abstract:
The CEESIowa calibration facility is designed to calibrate large (up to 762 mm, 30 inch) meters at high pressure (72 bar, 1050 psi). The Quality Control program is made up of three parts. The first part addresses management issues; it consists of the documented procedures and policies that govern the day-to-day operations. The second part addresses technical issues. Examples include uncertainty analyses, calibration records and software verification. The Measurement Assurance Program (MAP) is the third part of the CEESIowa Quality Control program. This paper discusses some components of the CEESIowa MAP.
Flowmeter Installation Effects Download PDF
Tom Kegel,
8/1/2003, Appalachian Gas Course
Abstract:
Flowmeter installation effects are the result of differences between the conditions in the field and those in a calibration facility. This paper provides an introduction to two of the most common field conditions: velocity profile distortion and swirl. The paper is divided into the following sections:
* simple description of the velocity profile.
* The profile and swirl produced by single and double elbows.
* Some effects on orifice, turbine and ultrasonic meters.
* The use of flow conditioners.
Flowmeter Calibration Download PDF
Tom Kegel,
7/1/2003, Appalachian Gas Course
Abstract:
This paper discusses issues associated with flowmeter calibration. It is divided into the following sections:
* Basic concepts
* Uncertainty issues
* Pressure transducer example
* Turbine meter example
* Cost issues
* Time issues
Quality Control Program of the CEESI Ventura Calibration Facility Download PDF
Tom Kegel,
5/1/2003, FLOMEKO
Abstract:
The CEESI Iowa Quality Control program is made up of three parts. The first part addresses management issues as described in the ISO 9000 series of standards. It consists of the documented procedures and policies that govern the day to day operations. The second part addresses technical issues as described in the ISO 17025 standard. Examples include uncertainty analyses, calibration records and software verification. The Measurement Assurance Program (MAP) is the third part of the CEESI Iowa Quality Control program. This paper discusses the components of the CEESI Iowa MAP.
Youden Analysis of Flowmeter Data - Four Case Studies Download PDF
Tom Kegel,
1/15/2003, Measurement Science Conference
Abstract:
This paper describes Youden analysis associated with flowmeter performance. A description of the method is followed by four case studies:
1. Several laboratories or facilities utilize a pair of flowmeters for intercomparison purposes. Youden analysis helps to identify why a particular participant disagrees with the rest.
2. A production calibration facility exhibits random effects due to test parts and measurement standards. Youden analysis quantifies the random effects associated with both the part and the facility.
3. Three flow measurements based on different operating principles are compared: a laminar flow element, a critical flow venturi and variable volume primary standard. Youden analysis of the results quantifies the repeatability of each measurement.
4. Two examples are described where Youden analyses have been added to test programs. In both cases the Youden analysis was not required to obtain a result but added confidence in that result. The first example involves testing at the CEESI Iowa calibration facility. The second example concerns a test program to identify pressure effects in ultrasonic flowmeters.
Maintaining Traceability of Multiple Flow Measurement Standards Download PDF
Tom Kegel,
1/23/2002, Measurement Science Conference
Abstract:
This paper describes a method to indirectly compare flowmeter standards to one another. Several artifacts are used to make the comparisons, in some cases the artifacts have extensive calibration histories. The uncertainty analysis is presented using test results as an example. The preliminary estimate of the uncertainty is +-0.15% at 95% level of confidence.
Thermometry in Measurement Download PDF
Joshua Kinney,
5/15/2000, 75th International School of Hydrocarbon Measurement
Abstract:
To determine reliable natural gas volumes, all variables must be measured correctly. Temperature is one of those variables. When temperature is measured incorrectly, it can have a pronounced affect on the bottom line.
COGFM Ch. 14.1 Joint API/GPA Gas Sampling Working Group : Phase II Experimental Testing Under Simulated Field Conditions Download PDF
Britton, C.L., Joshua J. Kinney,
12/1/1999, American Petroleum Institute
Abstract:
The American Petroleum Institute (API), Committee14.1, Gas Sampling Working Group, has contracted with various organizations to review existing sampling procedures and to perform experimental studies with the intent to revise and update the operating procedures. Phase I of the study was performed at the GRI natural gas Metering Research Facility (MRF) at Southwest Research Institute (SwRI) in San Antonio, Texas. SwRI contracted with Colorado Engineering Experiment Station Inc. (CEESI) to assist in part of the Phase II testing. CEESI utilized an existing wet gas test facility to simulate many of the field conditions encountered by the natural gas industry. By utilizing the wet gas test facility, the field conditions could be simulated, but data could be collected under a more controlled condition. The experimental program was designed to investigate the differences between sample point locations and the differences between various spot sample methods for filling cylinders. The word “differences” is emphasized to draw attention to the fact that absolute accuracy is not as important as repeatability. In the experimental tests reported herein, the most important thing to do is to be consistent in the operation of all instruments and equipment. By consistent operation, data obtained at different times can be compared with confidence. The test program consisted of three distinct test plans that simulated both summer and winter conditions, and with various gas compositions that ranged from 1030 to 1540 BTU/cubic foot.
Colorado Facility Advances Natural Gas Measurement Download PDF
Bj Richardson,
7/1/1999, Pipeline & Gas Journal
Abstract:
Colorado Engineering Experiment Station, Inc. (CEESI) is contributing two important resources to the natural gas industry - a re-circulating flow loop designed to study wet gas and its effects on measurement, and the first high volume, high-pressure natural gas calibration facility in the United States. For 35 years, CEESI has provided a full range of NIST traceable measurement services across the spectrum of industries requiring meter calibration and specialized testing.
A Hybrid Technique for Calibrating Flowmeters with Compressible Fluids Download PDF
Tom Kegel,
1/21/1999, Measurement Science Conference
Abstract:
Flowmeters for compressible fluids can be calibrated by one of two basic methods: primary or secondary. A primary calibration involves comparison with a system based only on primary measurements (mass, length and time). A secondary calibration involves comparison with a transfer standard that has been characterized by a primary system. Primary calibrations are more costly and have lower associated uncertainty than secondary calibrations. This paper describes a hybrid calibration technique that has lower cost than a primary calibration and lower uncertainty than a secondary calibration. An analysis of the uncertainty is proposed that is based on a novel application of a traditional statistical technique.
The Critical Flow Function, C*, For Humid Air Download PDF
Richard Caron, Charles Britton, and Tom Kegel,
6/21/1998, ASME Fluids Engineering Division Summer Meeting
Abstract:
The critical flow function (C*) that is used to calculate the mass flowrate of a gas through a critical flow venturi (CFV) has been determined for many pure gases and dry (moisture free) air. In those applications where moisture is present in an air stream, the critical flow function (C*) and the gas constant (R) will deviate from dry air. The magnitude of the deviation depends upon the pressure, temperature and humidity level. This paper describes a rigorous calculation method which shows the effect of humidity on both C* and R. A comparison of this rigorous method with previous data by other investigators is presented.
Measurement Comparison Programs In A Flow Calibration Facility Download PDF
Tom Kegel,
2/5/1998, Measurement Science Conference
Abstract:
A measurement comparison program (MCP) is an important component of a calibration laboratory measurement assurance program. It consists of using an artifact to compare the results of one laboratory with those of another. An MCP will maintain traceability and uncover any systematic effects that may be present but undetectable based on an uncertainty analysis. This paper discusses application of MCP techniques to flow measurement. Topics include artifact design, data interpretation, and the current status of some ongoing MCP activities.
The Application of Measurement Assurance Techniques in a High Capacity Automated Flowmeter Calibration Facility Download PDF
Tom Kegel and Richard Caron,
5/5/1997, 43rd International Instrumentation Symposium
Abstract:
The paper describes a study that forms part of a measurement assurance program (MAP) in place at Ford Motor Company. The purpose of a MAP is to assure on an ongoing basis that the total uncertainty associated with a measurement process meets the requirements of the customer. The gage repeatability and reproducibility study and statistical control chart are two traditional parts of the Ford MAP. This paper presents a new tool, the Youden plot, which combines features of both of these traditional techniques. This paper is divided into two parts: First, the test part, measurement process and traditional MAP program are described. Second, the new technique is described and applied to historical data.
Installation and Operation Errors in Gas Measurement Download PDF
Walt Seidl,
4/15/1997, 72nd International School of Hydrocarbon Measurement
Abstract:
Installation and operation errors may have an effect on measurement accuracy and therefore on company operations. This paper will present information for some types of installation/operation problems for common gas flow metering devices such as orifices, turbines, and positive displacement meters.
Program For Training A Measurement Technician Download PDF
Tom Kegel and Steve Stark,
4/15/1997, 72nd International School of Hydrocarbon Measurement
Abstract:
Despite the ongoing reorganizations in the natural gas industry, the effective training of technicians is a fundamental and critical part of any worthwhile training program. This statement will remain true as long as the measurement function continues to have a direct impact on company profits. In the natural gas industry, the old adage that a meter is the "cash register" is as true today as ever. While advanced computing and communications equipment helps speed the business function, the integrity of the volume measurement from a metering station is still as important as it always has been.
The once common title of "Measurement Technician" seems to be rapidly disappearing from the gas measurement industry. Today’s "Super Techs" must now take care of not only measurement equipment but computing, communications, compression, and a broader range of instrumentation. With the advent of new measurement technology, training is not quite as simple as it once was. No longer can the new employee be shown the basics of how to calibrate a chart recorder and change an orifice plate and then be "turned loose to learn the ropes" from the seasoned veterans.
This paper is a collaboration between the gas industry and a commercial training organization. It offers a fresh view of some basic issues involved in developing and maintaining a technician training program. The intent is to touch briefly upon a range of subjects with the hope of stimulating readers to think about elements of their own training program.
From NIST to Under the Hood: Flow Measurement Traceability at Ford Download PDF
Tom Kegel and Rich Caron,
5/1/1996, 42nd International Instrumentation Symposium
Abstract:
The calibration of the intake air mass flow sensor in an automobile is traceable to NIST through the following four steps.
1. A primary flow standard is traceable to NIST by mass and time standards.
2. Production test chambers that are calibrated against the primary flow standard.
3. A quality control test chamber that is also calibrated against the primary flow standard.
4. A sensor that is used to measure the mass flow of engine intake air.
This paper describes the four step process with the objective of estimating the uncertainty associated with the sensor installed under the hood. Discussions are made regarding the impact of hardware, environmental conditions, process complexity and cost issues for each of the four steps.
Flow Testing and Proving Natural Gas Electronic Measurement Equipment Using an Air Flow Facility Download PDF
Steve Stark and Tom Kegel,
3/20/1995, 3rd. International Symposium on Fluid Flow Measurement
Abstract:
The purpose of this paper is to describe some methods and reasons for laboratory calibration of flow measurement systems. This paper is organized into the following five sections:
1. Types of laboratory calibrations
2. Reasons for laboratory calibration
3. Calibration fluids
4. Capabilities of the Colorado Engineering Experiment Station
5. References
High Pressure Liquid Flow Calibration Download PDF
John Reiner, Taft Snowdon, and Gary Corpron,
10/24/1994, ISA International Conference
Abstract:
The flow calibration system described in this paper is believed to be unique. It was designed and built for the purpose of providing high pressure, high accuracy calibrations and tests of process measurement and control devices. The facility can be operated at pressures ranging from approximately 1 atmosphere to more than 1500 psia (103 bar) and flow rates from about 12 gpm to 2500 gpm (45.4 l/min to 11800 l/min). The design and operation of the system, its calibration, and an analysis of the system's uncertainty is described. The use of the system when calibrating flowmeters and pertinent calculations needed to determine calibration uncertainty are also illustrated.
Viscous Flow Tests of Coriolis Mass Flowmeters Download PDF
Gary Corpron,
8/5/1994, IMEKO XIII World Congress
Abstract:
Besides measuring mass and density, coriolis mass flowmeters are used to obtain a fluid’s viscosity from a measurement of the differential pressure across the meter. This paper describes how these measurements are achieved. It also describes a liquid viscous flow test stand that was designed and built specifically for the purpose of performing viscous flow tests and calibrations of Coriolis mass flowmeters. The flow stand has been shown to have a mass flow rate calibration accuracy within ±0.05% over the mass flow rate range from less than 0.5 kg/min to approximately 45 kg/min. The flowmeter test section incorporates pressure transducers to measure the pressure drop across the meter. The pressure drop signal is processed by the flowmeter electronics to calculate viscosity. This approach has been evaluated with a number of meters of different sizes and the results indicate a viscosity measurement accuracy within ±1% to ±3% for the viscosities in the range from 5 mPa’s to 100 mPA’s and ±3% for viscosities above 100 mPa’s. An error analysis for the test stand and test results obtained with Coriolis mass flowmeters are included in the paper.
Correlation of Hydrogen and Air Flow in Critical Flow Nozzles, Part 2: Calibration Results Obtained with Air and Hydrogen Download PDF
Gary Corpron,
5/17/1994, 1994 Conference on Advanced Earth-to-Orbit Propulsion Technology
Abstract:
A sonic venturi was calibrated against primary flow standards with air and then hydrogen to determine whether any performance variations occurred with fluid property changes. It was found that the agreement between the air and hydrogen data was excellent. This paper describes the experiments and presents the calibration results.
Standards and Procedures for Laboratory Class Meter Testing Download PDF
Tom Kegel,
5/8/1994, American Gas Association Distribution/Transmission Conference
Abstract:
This paper is a discussion of how to achieve traceability to NIST via a laboratory flowmeter calibration. It is organized into the following six sections:
1. This section introduces the concept of traceability in flow meter calibration.
2. This section describes primary calibration systems. Such systems provide for the measurement of flowrate by direct comparison to measurements of mass, length, and time.
3. This section discusses the components that contribute uncertainty to a primary system based calibration.
4. This section discusses the factors that affect the capability limits of a primary system. The discussion includes the capabilities of three primary systems operated by CEESI.
5. This section describes the use of check standards to confirm the stable operation of a primary system. Typical data are presented.
6. This section describes enhancing traceability by performing intercomparison tests between primary systems. Data are presented of tests between the CEESI systems and those of other laboratories.
Intercomparison Tests of Gas Flow Rate Standards Download PDF
Masaki Takamoto,
10/1/1993, Proceedings, FLOMEKO '93
Abstract:
Intercomparison tests of primary calibration facilities for sonic Venturi nozzles have been made among NRLM (National Research Laboratory of Metrology, Japan), PTB (Physikalish - Technische Bundesanstalt, Germany) and CEESI ( Colorado Engineering Experiment Station, Inc, U.S.A.). The Facilities of these three laboratories are based on different method, i.e. volumetric (constant volume tank), volumetric (bell prover) and gravimetric (pressure vessels), systems, respectively. Six nozzles of 25 to 200m3lh were used for the tests. The nozzles were calibrated together with straighteners, which satisfy ISO and ASME standards, installed upstream of the nozzles. The results were agreed within the uncertainties of the calibration facilities of the three laboratories, 0.1%. Effect of the straightener on calibration of a nozzle was also investigated. It is recognized that the straightener minimizes the effect of upstream disturbances. However, a small nozzle is not affected by the disturbances even if the straightener is not installed.
A Precision, High Pressure, Liquid Flow Calibration Stand Download PDF
John Reiner, Taft Snowdon, and Gary Corpron,
7/25/1993, National Conference of Standards Laboratories Annual Workshop and Symposium
Abstract:
There is a need for a flow calibration system capable of performing mass or volumetric calibrations of liquid flowmeters at high pressures. This paper describes a system that can be operated at pressures ranging from approximately 1 atmosphere to about 2200 psia and flow rates ranging from approximately 12 to 2000 gpm. The calibration system is based on static weigh, time, temperature methods. The design and operations of the system, its calibration, and an analysis of the uncertainty of the system is described. Finally, the use of the system when calibrating a flowmeter and pertinent calculations needed to determine the uncertainty of the calibration are illustrated.
Laboratory Calibration of Flow Measurement Systems Download PDF
Tom Kegel,
5/16/1993, American Gas Association Distribution/Transmission Conference
Abstract:
The purpose of this paper is to describe some methods and reasons for laboratory calibration of flow measurement systems. This paper is organized into the following five sections:
1. Types of laboratory calibrtaions
2. Reasons for labortoty clibration
3. Calibration fluids
4. Capabilities of the Colorado Engineering Experiment Station
5. Refrences
Laboratory Calibration of Fluid Flow Meters Download PDF
Steve Caldwell and Walt Seidl,
5/16/1989, 64th International School of Hydrocarbon Measurement
Abstract:
Calibration of flowmeters can often be accomplished in actual use conditions, by flowing the actual fluid in the plumbing configuration the measurement is being made in. Secondary field calibration such as mentioned above, have many advantages but lack the control and precise measurement that can be obtained under laboratory conditions. Laboratory calibrations can also simulate plumbing configurations and simulate plumbing configurations and stimulate the operating densities that the flowmeter will experience under actual use conditions and offer the advantage of being able to precisely control effect that could effect the performance of fluid flowmeters.
Methods and Benefits of Laboratory Calibrations of Compressible Fluid Flowmeter Download PDF
Steve Caldwell and Mike Lewis,
4/4/1989, Conference of the American Institute of Chemical Engineers
Abstract:
Laboratory calibration of compressible fluid flowmeters very often can provide an improvement in the quality and efficiency of many products and processes. Methods for the calibration of flowmeters are varied, secondary methods that rely on the use of transfer standards such as a calibrated subsonic meter system, calibrated turbine meters system or the most reliable transfer device the critical flow venturi can be installed in series with the meter or metering system that you wish to have calibrated or proved. Primary methods rely upon fundamental measurement or standards such as mass, length and time, can offer an increased accuracy in measurement but are generally limited in capacity. The combination of the two methods, secondary and primary, offer reliable meter proving methods when used in conjunction with quality support instrumentation and personnel.
Laboratory Calibration of Fluid Flow Meters Download PDF
Walt Seidl,
5/24/1988, 63rd International School of Hydrocarbon Measurement
Abstract:
Gas and liquid flowmeters often may be calibrated under laboratory conditions when field proving is impractical or impossible. Calibration in a laboratory offers the advantage of operating in a controlled environment which can be important in flowmeter evaluation. Laboratory facilities are available to provide calibrations to 0.1 percent of reading or better.
A Fluidic-Pneumatic Interface Amplifier Download PDF
Charles Britton and Steve Stark,
11/16/1986, Automatic Control Conference
Abstract:
The development of a low cost, reliable, linear pressure amplifier to interface Laminar Proportional Amplifiers (LPA) to pneumatic controllers is presented. The amplifier consists of an LPA input stage and an output stage consisting of a venturi in series with a bellows nozzle valve. The LPA output drives the bellows nozzle valve, thereby altering the flow rate through the venturi. The pressure within the venturi throat region, which is the amplifier output, changes with the flow rate. Non-linear characteristics, due to supersonic flow within the venturi, are altered through the use of feedback to the LPA input. A computer based model, to aid in optimizing the amplifier design, is developed. This model incorporates the effects of shock waves and boundary layers within the venturi. Good correspondence between the model and an experimental prototype is shown.
A Large Capacity, High Accuracy Oil Flow Test Facility Download PDF
Charles Britton, Walt Seidl, and Steve Caldwell,
11/16/1986, International Symposium on Fluid Flow Measurement
Abstract:
This paper describes a new oil flow test facility that has been recently constructed and put into operation at CEESI (Colorado Engineering Experiment Station, Inc.). The facility presently uses a mineral oil with a kinematic viscosity of approximately 5 centistokes as the calibration fluid and can measure volumetric flow rates from 0.1 to 284 cubic meters/hour (0.5 to 1250 GPM). It is possible to change the fluid if a different viscosity is required.
The oil flow test facility was designed and constructed by CEESI under a contract with the American Petroleum Institute (API) Orifice Project Management Committee. This facility was used in the development of a data base for flange-tap orifice meters at low Reynolds numbers.
Laboratory Calibration of Transmission Gas Flow Metering Systems Download PDF
Walt Seidl and Steve Caldwell,
5/20/1985, American Gas Association Distribution/Transmission Conference
Abstract:
A description is given of the capabilities and procedures used for the calibration of transmission gas flow metering systems at Colorado Engineering Experiment Station, Inc.(CEESI). CEESI is a not-for-profit organization that has been performing gas flow metering calibrations in a laboratory environment for eighteen years. Calibrations are performed by use of critical flow venturis that have been proven on CEESIs in-house primary standards which are traceable to basic national standards. Calibrations have been performed in line sizes up to 48 inches with flow rates up to 135 million SCFD. Both steady-state and cycling flows can be used during calibrations.
Droplet Flux Estimation in Horizontal Annular-Mist Pipe Flow Using a Thermal Anemometer Download PDF
Tom Kegel,
1/1/1984, Mass Flow Measurements
Abstract:
The successful application of a hot wire technique to measure the distribution of droplet flux in horizontal annular-mist flow is described. Measurement of the flux, rather than the mass, of the droplets is a unique application of such a technique. Contamination of the probes by mineral deposits from the tap water acts to reduce the sensitivity of the anemometer to droplets. Normalized data of the flux distribution are shown to be valid despite the contamination problem. Results from experimental work are presented that show the dependence of droplet flux on inlet conditions as well as the liquid and gas flow rates.
A Proposed Pressure Amplifier for a Temperature Control System Download PDF
Tom Kegel and D. E. Limbert,
11/1/1981, Temperature: Its Measurement and Control in Science and Industry
Abstract:
This paper discusses the development to a totally pneumatic, furnace temperature sensing system. This system produces a pressure signal of 0-0207 kPa (0-30 psi) proportional to temperature over the range of 540-1650 °C (1000-3000 °F). This pressure is used as the feedback signal to a furnace temperature controller that operates valves to control the flow of air and gas to the combustion chamber. The system consists if three stages: a temperature probe, a preamplifier, and a power amplifier. The probe is a Fluidic Capillary Pyrometer, (FCP) that produces a very low pressure signal proportional to temperature. This signal is amplified to approximately 1.0 kPa by a series of Laminar Proportional Amplifiers (LPA)2. The power amplifier, consisting of a venturi in series with a flapper valve, amplifies the signal to the required 207 kPa. Due to the non-linear behavior of the power amplifier, a feedback linearizing scheme is employed. Analysis and data are presented to demonstrate the resulting improvement in linearity. Finally, a computer based model, to aid in the design of the power amplifier, is presented. The objective of the development of this system is to replace the thermocouple, and related electronic components, in a furnace control system with pneumatics. This is desirable for several reasons, chief among them relating to the FCP itself. The FCP, which is made of a ceramic material, has a much longer life than a thermocouple. The FCP offers an attractive method of continuous measurement of extremely high temperatures, such as those found in molten metal. Hostile environments, such as where electromagnetic or nuclear radiation is present, do not affect the FCP. There are also advantages to having the entire control system be pneumatic. If one operates in an explosive environment, pneumatic control is the only option available. By avoiding hybrid pneumatic/electronic systems, costly interface devices can be eliminated. Finally, because of their inherent simplicity and lack of many moving parts, pneumatic controllers tend to be more reliable than their electronic and mechanical counterparts.
Quality Assurance for Gas Flow Measurement Download PDF
B. T. Arnberg and H. S. Hillbrath,
11/11/1973, American Society of Mechanical Engineers
Abstract:
Primary gas flow standards are now available which can compare gas flow measurements of up to 20 lb/sec of air to national standards of mass and time. The predominant type of secondary standard used for transfer or working meters is the critical flow venturi. Recommendation for the design, construction, and calibration of secondary standard critical flow venturis is given. Some recent performance results for discharge coefficient and choking pressure ratio are summarized. Suggestions are also made for test procedures to be used with these devices.
Two Primary Methods of Proving Gas Flow Meters Download PDF
B. T. Arnberg,
5/9/1971, Symposium on Flow
Abstract:
Abstract not available.
Practice and Procedures of Error Calculations Download PDF
B. T. Arnberg,
5/9/1971, Symposium on Flow: Its Measurement and Control in Science and Industry
Abstract:
The purposes of this paper are to briefly summarize error analyses for measurement systems, and to apply the principles to critical (sonic) flowmeters in preparation for international standardization. The literature on error analysis is reviewed and inadequacies in current practices are discussed. Recommendations are made to reduce misunderstandings in terminology. Procedures are given for calculating and reporting the uncertainty in experimental results. The importance of performing separate analyses of random and bias errors is stressed. This paper covers the following topics:
1. Types of measurements, digital and analog
2. Types of errors, illegitimate, constant and variable bias, random
3. Criteria for rejecting outliers, Thompsons Tau Test
4. Random error analysis, confidence levels, Students uncertainty estimation for individual and mean results, uncertainty in mean lines
5. Sensitivity determinations, dimensional and dimensionless
6. Error propagation, root-sum-square and linear addition of component errors
7. Method of equal effects for test planning and data analysis
8. Reporting of uncertainties
Most of the procedures are illustrated. A final example is given using a critical (sonic) flowmeter as a standard for calibration of a subsonic orifice flowmeter.
Large Capacity and Unusual Proving Facilities Download PDF
B. T. Arnberg and Charles Britton,
5/1/1971, American Gas Association Distribution Conference
Abstract:
Colorado Engineering experiment Station, Inc. (CEESI) has its origin in a program that was started at the University of Colorado in 1951 in which an experimental evaluation of rocket nozzles was conducted. From 1956 to 1965 the program concentrated on gas flow measurement problems of various types. Primary standards for flow measurement, transfer standards, and transducer performance characteristics were studied.
In 1966 an opportunity arose for a large expansion in research capability when air force ICBM missile sites were declared surplus. A nonprofit corporation (CEESI) was formed for the acquisition of an Atlas"E" site, along with a large amount of property from other sites that would be useful in building the laboratory. The missile site has been modified to function as a flow laboratory, and much progress has been made in extending the flow capabilities and improving the accuracy of the facility. In addition to the facility capability described in this paper, special gas flow calibration and evaluation programs may be conducted using the large amount of equipment that is available.
Review of Critical Flowmeters for Gas Flow Measurement Download PDF
B. T. Arnberg,
12/1/1962, ASME Journal of Basic Engineering
Abstract:
Critical Flow Meters for accurately measuring the mass flow rates of nonreacting real gases were reviewed. Discussions were presented on theoretical flow functions, on parameters for correlating discharge coefficients, and on the importance of real gas properties. The performance characteristics of critical nozzles and orifices of several designs were reviewed. Approaches were discussed to problems which must be researched before the fullest potential of this type of flow measurement can be realized.
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