AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE GAS DETERMINATOR (cont’d)IIIINSTALLATION (cont’d)(b)Chart Recorder (cont’d)(vii)Turn the knurled adjusting knob (which also serves as a pulley) clockwisewhen viewed from the top, and, as the chart advances, ensure that it entersthe guide channels at top and bottom of the platen.Swing the unit back into place and by slight pressure at the left hand endpush it over the ramp which holds it in the working position. The unit will dropinto place when the correct position is reached. At this position it is possibleto feel a positive stop in each direction preventing further swinging actionabout its pivots.Cutting Off ChartThis may be carried out at any time but the entire roll can be rewound if required.Use a sharp knife or razor blade and make a straight cut as nearly vertical aspossible. This can be anywhere within the 4½” to the left of the pen. Gently ease thechart out from the guide channels in order to cut the extreme edge if necessary andensure that the leading edges are re-entered into the channels.Remove the belt from the left hand pulley and tilt the re-wind shaft to the left until theroll clears the chart unit top plate then lift the shaft out of its bottom socket.Grip the roll firmly and turn the pulley anti-clockwise for about half a turn to releasethe trapped leading edge of the chart.Pull the shaft upwards and it should slide out of the rewound roll.Refit the rewind shaft, inserting the lower end into its socket first, then swinging theshaft into the slot in the top plate. Give the shaft a turn or two in a clockwise directionto ensure that it is free, then refit the belt.The Chart should now be picked up automatically and rewound when it reaches therewind shaft.The pen used on the Arkon 63 Pressure Recorder is now a fibre-tip throwaway type.To replace exhausted fibre-tip pen, pull out from the holder and push in replacement.After refitting ensure that the fixing boss lies parallel with the chart face. The nib isdesigned to work in this position. If the nib is at right angles to the chart, the penwill be trapped when the door is closed.Zero AdjustmentThis is controlled by a screw in the top left hand corner of the case flange which isvisible when the door is open. A screwdriver is needed for adjusting the position.This is to discourage unauthorised or unwitting adjustments. Turn clockwise to raisethe pen and anti-clockwise to lower the pen.117