Some Notes on the Manufacture and Performance of Slip-cast Tank Blocks

JSGT 1931 V15 T083-T106

The advances made in the glass trade have, naturally enough, left the block-maker rather behind in progress, and blocks which a few years ago gave satisfactory service, and even now will show up favourably in use with coloured glass at moderate rates of working out, are no longer acceptable. If the factors which have produced this alteration in the demand on tank blocks be analysed, some will be found to be actually favourable to the block-maker, always provided he understands the conditions of use. Furnace temperatures are under better control, and are more uniform. Batches are better balanced, molten salt-cake is not allowed to wander at large, and, in spite of the generally higher soda content of the glasses the purely chemical corrosiveness is not decisively greater. The glass level is kept constant, and the week-end shut-down is either abolished or kept under as careful control as the working periods. Founding temperatures are decidedly higher, but this is not in itself a major count; any trouble that might arise on this account could be obviated by providing blocks of higher ultimate refractoriness, a matter of choice of material rather than of technique. The necessity for careful dressing and adequate cooling of the joints is now well understood.

Percy Haller