AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE GAS DETERMINATOR (cont’d)(b)Chart Recorder (cont’d)MANUFACTURERS :ARKON INSTRUMENTS LTD.(T.E.M.E.),2A THE CROFT,CROFT STREETLECKHAMPTONGLOS., GL53 0ED(Tele:) 01242 228745.(c)Temperature ControllerSee Eurotherm Operating Manual.IVTEST PROCEDURETURN on the cooling water and switch on the furnace.SET the temperature controller to the required temperature (850 °C) and allow the furnace toattain equilibrium at this temperature.INTRODUCE a weighed quantity (1 – 2 g) of sand into one of the special thin-walled coppersample tubes (3 in long x ¼ in diameter, closed at one end) and plug the open end withignited aluminium silicate fiberfax.UNSCREW the spring-gun assembly and insert the sample tube with the gun in the ‘loaded’position.REPLACE the gun assembly and pass a stream of oxygen-free nitrogen through theapparatus at a rate of about 1 litre per minute with the “GAS INLET” and “EXHAUST” taps inthe open position and the “RECORDER” tap shut. After two minutes all oxygen (or gasesfrom a previous test) should have been expelled.SHUT OFF the supply of nitrogen, then :-(a)(b)(c)(d)(e)Turn “GAS INLET” to “shut”.Turn “RECORDER” to “open” and wait for two minutes to allow the gas in the tube toattain furnace temperature.Turn “EXHAUST” to “shut”.Switch on the recorder.Inject the sample tube into the hot zone.118