AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE-DIETERT MOULD PERMEABILITY ACCESSORYIGENERAL PRINCIPLESThis accessory can be used with either the Standard Permeability Meter or the ElectricPermmeter, to measure the permeability of the actual mould surface in permeability units.IIDESCRIPTIONThe unit consists of a special contact head fitted with a sponge rubber, sealing washer andfixed aperture connected by a length of PVC tubing to a bell-shaped adaptor which fits ontothe centre post of either the Standard Permeability Meter or the Electric Permmeter.By means of this accessory air at a known pressure can be forced through the mouldsurface and from the drop in pressure across an orifice the permeability can be obtained.The aperture in the contact head has been designed to give a reading on a standard testspecimen equivalent to that which would be obtained if the permeability of the specimen wasdetermined in the normal way.A sliding metal collar inside the contact head ensures that the aperture remains constantwhen pressed against a mould surface.IIITEST PROCEDURE(A)Standard Permeability Meter(a)(b)(c)(d)Seal the bell-shaped adaptor in position on the Permeability Meter.Start the flow of air with suitable orifice in position as for normal permeabilitytests.Press contact head firmly against the mould surface and take reading ofpressure on manometer.To obtain permeability number consult perm. table or use rapid readingquadrant.72