MR-HM 150.17 Calibration of pressure gauges Vocational Training Equipment Fluid Mechanics Experiment Equipment Description • operation of a Bourdon tubepressure gauge and a pistonmanometer In the field of metrology, calibration describes a process for detecting deviations in a measuring instrument compared to a reference instrument or universally accepted standard value. Thisobserved deviation is taken into accountin the subsequent use of the calibratedmeasuring instrument and adjusted ifnecessary. MR-HM 150.17 is a device designed as anintroduction to the basics of checkingand calibrating a manometer. A piston manometer is connected to aBourdon tube pressure gauge via a pipe. Piston manometers are especially suitedto producing well-defined pressures in liquids or gases and have been used foryears as one of the most accuratemethods for calibrating pressuregauges. A defined force is produced by loadingthe piston with weights. The ratio offorce / piston cross-sectional area results in a defined test pressure. Hydraulicoil is used to transfer the force. If thepressure in the system rises, the forceacts against the spring of the Bourdontube pressure gauge. The test pressurethat is produced can be read on themanometer’s transparent dial. Thespring mechanism – and thus the way inwhich the Bourdon tube pressure gaugeworks – is clearly visible through thetransparent dial. Loading the calibrated piston manometer with weights produces a very accurate, reproducible calibration pressure,which can be used to check and calibrate the manometer. Learning objectives/experiments • working principle of a Bourdon tubepressure gauge • calibrate manometers, read off appliedpressure • determine systematic errors • principle of operation and working witha piston manometer Specification [1] Bourdon tube pressure gauge for pressure measurement [2] transparent dial face with a view of the springmechanism [3] accurately fitting piston and cylinder of the pistonmanometer without seals [4] hydraulic oil for transfer of the force [5] hydraulic pump with storage tank and bleed mechanism Technical data Piston manometer • pressure piston: diameter: 12mm • hydraulic cylinder: diameter: 25mm, length=225mm • oil: ISO viscosity grade: VG 32 Set of weights • weight holder: 385g / 0,334bar • 1x 193g / 0,166bar • 4x 578g / 0,5bar Measuring ranges • pressure: 0…2,5bar LxWxH: 400x400x400mm Weight: approx. 16kg Scope of delivery 1 experimental unit 1 set of weights 1 oil (500mL) 1 set of instructional material
