AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE- DIETERT ELECTRIC PERMMETERIGENERAL PRINCIPLESThis Permeability Meter employs the orifice method for the rapid determination of sandpermeability. Air at a constant pressure is applied to a standard test specimen (in aspecimen tube), and the drop in pressure is measured on a pressure gauge, which iscalibrated directly in permeability numbers.IIDESCRIPTIONA high speed blower, with a pressure balancing mechanism, delivers air to the system at 100mm water pressure. The speed of this blower is controlled by a rheostat on the right-handside of the instrument.A three-way valve operated by a lever on the left-hand side of the instrument allows the airto flow to either the pressure gauge or to the centre post.By rotating the centre post an ‘O’ ring is expanded and forms an air-tight seal with aspecimen tube.The hole in the centre post is threaded to accommodate one of the two calibrated orifices.The pressure gauge dial has three separate graduations. The inner scale gives air pressurein mm of water, and the other two are calibrated directly in permeability numbers one foreach orifice.Two check jets are supplied with each instrument for checking the calibration.69