The design and implementation of a fully automated crossfloat system for the comparison of piston gauges in both gauge and absolute measurement modes

M. Bair, P. Delajoud and M. Girard, DH INSTRUMENTS
Abstract:
The pressure crossfloat is a well established method for comparing the output of piston gauges with various media. The crossfloat is the most common method for determining the area of a test piston-cylinder relative to a reference piston-cylinder. The traditional crossfloat procedure is a tedious manual process that is highly dependent on operator skill, patience and experience. Due to the need to access the masses to make small mass adjustments, operation is normally gauge mode only.
In order to meet a high demand for low pressure, gas operated piston gauge systems, DHI has designed and implemented a fully automated crossfloat system over the range of 9 kPa to 7 MPa. The intent of the system is to be able to perform unattended crossfloats to determine the test piston-cylinder performance characteristics and determine effective area in either absolute or gauge mode. The crossfloat station was put into regular operation in late 2006 and has exceeded the expectations of its designers.
The automation is made possible by the use of two automated mass handling systems and a low differential pressure transmitter used to determine the final equilibrium point between the two piston-cylinders.
This paper describes the design of the automated calibration system, the challenges of its implementation and the results of numerous crossfloats performed over six months of automated operation.
Keywords:
pressure, effective area, crossfloat, automation, base ratio, direct ratio
Download:
IMEKO-TC16-2007-039u.pdf
DOI:
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Event details
IMEKO TC:
TC16
Event name:
Cultivating Metrological Knowledge
Title:
3rd Conference on Pressure Measurement (together with 20th TC3 Conference on Measurement of Force, Mass and Torque & 1st TC22 Conference on Vibration Measurement)
Place:
Merida, MEXICO
Time:
27 November 2007 - 01 December 2007