Fluke 2470 specifications Controlled Clearance Cylinder

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RUSKA 2470

Users Manual

SECONDARY

PRESSURE

PRESSURE IN

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Figure 2-3. Controlled Clearance Cylinder

When the simple cylinder of 2-1 is subjected to an increase in pressure, the fluid, exerting a relatively large total force normal to the surface of confinement, expands the cylinder and thus increases its area. A pressure-drop appears across the cylinder wall near point A, resulting in an elastic dilation of the cylinder bore.

It can be shown that the effective area of the piston and cylinder assembly is the mean of the individual areas of the piston and of the cylinder; therefore as the pressure is increased, the cylinder expands and the effective area becomes greater. The rate of increase is usually, but not always, a linear function of the applied pressure. The piston also suffers distortion from the end-loading effects and from the pressure of the fluid, but to a much lesser extent than the cylinder. It is evident then, that the simple cylinder of 2-1 would be inadequate for a primary piston pressure gauge unless some means of predicting the change in area were available.

The increase in the effective area of the simple cylinder is also accompanied by an increase in the leakage of the fluid past the piston. Indeed, the leakage becomes so great at some pressures that insufficient floating time can be maintained for a proper pressure measurement.

In Figure 2-2, the pressure fluid is allowed to surround the body of the cylinder. The pressure drop occurs across the cylinder wall near the top of the cylinder at point B, but in the opposite direction to that of the simple cylinder in Figure 2-1. In consequence, the elastic distortion is directed toward the piston, tending to decrease the area of the cylinder.

Again, the change in area with changing pressure places a limit on the usefulness of the cylinder in 2-2 for it as a primary instrument. But some benefit results from the use of this cylinder in the construction of a piston pressure gauge because higher pressures may be attained without a loss in float time. A small sacrifice is made in the float time at lower pressures because the total clearance between piston and cylinder must necessarily be greater at low pressure for the cylinder in 2-2 than for the cylinder in Figure 2-1.

In the controlled-clearance design of Figure 2-3, the cylinder is surrounded by a jacket to which a secondary fluid pressure system is connected. Adjustment of the secondary, or jacket, pressure permits the operator to change the clearance between the cylinder and piston at will. A series of observations involving piston sink rates at various jacket pressures leads to the empirical determination of the effective area of the assembly. Throughout the world, the controlled-clearance piston pressure gauge is an accepted standard of pressure.

Piston pressure gauges having very high resolutions may be made by using simple and reentrant cylinders. A determination of the distortion coefficients of such gauges may be made by direct comparison with a controlled-clearance gauge. Most piston pressure gauges have some elastic distortion, but some, used in the very low pressures, have only small coefficients and, in some instances, correction for distortion may be neglected.

2-2

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Contents Ruska Limited Warranty and Limitation of Liability Table of Contents Appendices List of Tables Ruska List of Figures Ruska Introduction How to Contact FlukeSafety Information Compressed GasLubricants and Seals Symbols Used in this ManualHeavy Weights Oxygen CompatibilitySpecifications Low Range PistonAccuracy Humidity RangeGeneral Piston Pressure Gauge Considerations Types of Piston Pressure GaugesControlled Clearance Cylinder Calculations Measurement of Pressure with the Piston Pressure GaugeBuoyant Effect of the Air Elastic Distortion of the CylinderGravity Temperature Reference Plane of MeasurementsReference Plane Determination Is the density of the test media Crossfloating BibliographyGeneral Piston Pressure Gauge Considerations Ruska Description General InformationDescription of the Mass Set Description of the Gauge BaseDescription Ruska Installation IntroductionAlways remove the thermometer before shipping the gauge base Installation Ruska Precautions OperationLow Range Piston Assembly GeneralOperation 24-580 Bearing 2460-4-25 2460-5-6 Handling the Low Range Piston and Cylinder Step Low Range Piston and Cylinder Showing O-Ring Groove Mid Range Piston Assembly Section View, Mid Range Piston/Cylinder Thrust Cylinder Assembly Spacer Bearing 2460-70-2 2460-70-3 High Range Piston Assembly 11. Retaining Nut and Bearing12. Section View, High Range Piston/Cylinder 13. Parts Required for High Range Piston Operation Establishing Pressure Gauge PressuresAutomating the Calculations and Data Storage 16. Float PositionMaintenance of the Gauge LeaksRuska Piston / Cylinder Cleaning Instructions General Information and PreparationFunctional Testing of Piston/Cylinder Assemblies Cleaning the Low Range Piston/Cylinder AssemblyPiston / Cylinder Cleaning Instructions Preparations for Cleaning the Low Range Cylinder Preparing the Low Range Cleaning Tool Step Materials for Cleaning the Mid Range Piston/Cylinder Mid Range Piston/CylinderPreparing the Mid Range Cleaning Tool Cleaning the High Range Piston/Cylinder Assembly Materials for Cleaning the High Range Piston CylinderCleaning the High Range Piston/Cylinder Assembly Gmq33.bmp 13. Cleaning the High Range Cylinder 14. Drying the High Range Cylinder Explanation of Pressure Calculation Worksheet Temp. Coef. x actual temperature expected temperature For English UnitsK2 = 1/ g1 1 − ρa / ρb For SI UnitsAe t Explanation of Pressure Calculation Worksheet a Ruska Date Ruska Expected Temperature, t Ruska Nitrogen Density English Units 0 to 1000 Psig Equation A-4 Air DensityEquation A-4 Air Density Nitrogen Density English Units 1,000 to 15,000 PsigZero Air Density SI Units 0 MPa to 20.7 MPa Nitrogen Density SI Units 0 to 6.9 MPaNitrogen Density SI Units 6.9 MPa to 100 MPa Helium Density SI Units 0 to 6.9 MPaConversion Factors Table B-1. Conversion Factors To Convert From Multiply ByRuska Glossary GlossaryDUT +INF, -INF Pressure Factor Sink Rate Ruska

2470 specifications

The Fluke 2470 is a versatile and highly regarded data acquisition system designed for a wide range of applications in electrical testing and measurement. Known for its precision and reliability, the Fluke 2470 is particularly popular among professionals who require accurate data for analysis and reporting.

One of the standout features of the Fluke 2470 is its high-performance data acquisition capabilities. It supports multiple channel inputs, allowing users to monitor and log various electrical parameters simultaneously. This multi-channel functionality is essential for complex testing scenarios where multiple variables must be tracked in real time.

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In conclusion, the Fluke 2470 combines high-performance data acquisition, multi-channel capabilities, advanced measurement technologies, and user-friendly features, making it a top choice for professionals in a variety of fields. Its robust design ensures that it meets the demands of rigorous testing while providing accurate and reliable data, crucial for informed decision-making.