AFS Foundry Sand Testing Equipment Operating Instructions Manual

RIDSDALE-DIETERTGREEN COMPRESSION STRENGTH MACHINE (AFS) (cont’d)IIDESCRIPTION (cont’d)Three ranges of spring balance are available for this machine :-0-4.5 psi, 0-12.5 psi and 0-31 psi on a 2 inch diameter x 2 inch height specimen.A sample holder is provided with each machine to facilitate the positioning of the specimenin the compression heads and in the case of the low capacity balance a special sample plateis supplied on to which the specimen can be stripped directly from the split specimen tubewhen dealing with very weak sand mixes.IIITEST PROCEDURE(a)(b)(c)(d)(e)(f)Prepare a test specimen on an AFS Standard Rammer. For routine purposes thiscan be made on a green sand test specimen after the permeability has beendetermined. For research work a fresh specimen should be prepared.Carefully transfer the test specimen to the compression machine by means of thesand pan provided and place centrally on the lower compression head.If the sand is very weak prepare a specimen in a split specimen tube and use a lowcapacity spring balance, with a more open scale, having a maximum reading of 4.5psi on an AFS 2 inch diameter x 2 inch height specimen. In this case the specimenshould be stripped directly on to the special sample plate provided with the lowcapacity balance.Rotate the hand-wheel in a clockwise direction until the weight of the specimen issupported by the spring balance. Zero the moving pointer by means of the knurledscrew on the top of the balance. Set the slave pointer to zero.Ensure that the compression heads are free to self-align and turn the hand-wheel ina clockwise direction until the load begins to the applied to the specimen. Turn thehandle slowly, at the rate of about 30 lb per minute, until the specimen collapses.(This is achieved most easily by using both hands on the rim of the hand-wheel).Record the compression strength as indicated by the slave pointer.IVMAINTENANCEKeep the machine clean and the hand-wheel shaft lightly oiled. Ensure that the lowercompression head is free to move and therefore self-aligning.VRECOMMENDED SPARESPart No.Description607 Sand pan628 0-4.5 psi capacity spring balance629 0-12.5 psi capacity spring balance.630 0-31 psi capacity spring balance.81