CHAPTER V
VERTICAL RETORTS AND CHAMBER OVENS
The present-day popularity of the vertical retort and chamber oven is, no cloubt, tlie natural outcome of the growing preference for carbonization in bulk, and the ten-dency for the gas en.gin.eer to relieve himself as far as possible of the vagaries and expense of manual labour. Although the evolution of the vertical retort in its modem form has taken place within the last decade, the idea is by no means a new one, for so long ago as 1828 Brunton patented an intermittent system having quite a number of features similar to those of the prevailing types of to-day.
The systems of vertical retorts at present in use may be divided into three distinet types :—■
(a) Continuous types.
(b) Intermittent types.
(c) Continuous-intermittent types.
Of these the first-named system aims at solving the problem of ideal carboniza-tion ; that is, the continuous admission of relatively small charges of coal accom-panied by the continuous extraction of that which has undergone distillation. Hence, undesirable variations in the quantity of gas evolved (inseparable from intermittent charging) are completely avoided. Intermittent types of vertical retorts embrace the principles employed in the horizontal beuch, i.e., a definite charge of coal is arranged for at stated periods, the retort being emptied at the end of the distillation spell. Except for the purpose of “ scurfing,” continuously operated retorts are never emptied. Continuous-intermittent systems are those whose design permits of the retorts being operated on either the continuous or intermittent principle. So far they have not gained mueh headway in this country.; but as they are of most recent origin, their wide adoption is scarcely to be looked for at present.
It is not proposed to give mueh attention here to forms of vertical retorts other than those which have been actually employed in this country and are at work at the present time. In addition, to the systems described below, many otters, originating from America and the Continent, are to be found.
Among the earlier systems was the Settle-Padfield, in which tlie retort com-menced in a vertical plane, but turned oft at an angle at the base, so that the coke was discharged through the side of the bench, and not at the bottom. Charging was arranged for on continuous lines, but the coke was withdrawn at definite intervals, so that the amount of free space in the retorts was subject to variation. The system has now been discarded.
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