AS 1774.7-2008 pdf free download

AS 1774.7-2008 pdf free download.Refractories and refractory materials – Physical test methods Method 7 : Permeability to gases.
4 PrincIple
A stream or dry gas is passed through the test piece. and the pressure drop across the test piece is recorded for at least three different rates of flow From these values, and from the size and shape of the test piece, the permeability of Ihe material Is determined by calculation
5 Apparatus
5.1 General
The general layout of the apparatus is shown diagramalically In figures 1 and 2 Figure 1 shows the arrangement for the pacage of gas under pressure and figure 2 (or the passage of gas under suction. The connecting piping shall be made of glass in preference to rubber, and shall be as short as possible, so that the pressure loss in the apparahis is very small when compared with the pressure loss produced by the test piece
5.1.1 Supply of gas (under pressure or suctlon) consisting of a reservoir of gas at constant pressure
5.1.2 Test piece holder, with gas-tight seals at the sides of the test piece. Gas tightness shall he en. bured by a rubber membrane lhdt is uflaied to a pressure oF 0.2 N/mm2 to 0,4 N/mm’. See figure 3.
MOlE ‘ Modifications will be required if the alternative lest piece sire (see note to O,1)is used.
5.1.3 Liquid manometer, of hue U-Liibe type. Ioi measuring the difference In pressure between the two faces of the test piece. The usual experimental precautions for this type of measurement shall be taken, so that the error in the pressure determination does not exceed 1 °/. (including error in reading column height, meniscus error, error in the verticality of the manometer, and measurement of the density of the manomeler liquid) The pressure shall be delermined close to one face of the test piece in the vessel containing the test piece holder
(5.1.2).
NOTF A lower pressure reading may result when the preasure away frurn the lest psece Is dete,rnined in the connecting lubes
5.1.4 Gas flow measuring equipment, consisting of a sensitive floating flowmeter calibrated For a given temperature and pressure of entry. The flowmeter shall be accurate to within 2 %. The flowmeter shall be calibroted periodicelly for the gas to be used, and only the middle section of its measuring scale shall be used.
For the measurement of permeability to air only, the rate of air flow Is measured by the displacement of air by water ucinri Oraduated cylinder device and a chronometer
5.1.5 Vernier callipers, In accurdance with ISO 6906,
5.1.8 DryIng oven, capable of being controlled at
110°C ± 5 C
5.1.7 Impermeable dummy test piece. For example an aluminium cylinder
6 Test pieces.AS 1774.7-2008 pdf free download.