THE HORIZONTAL RETORT BENCH
101
the fumace front, and in four similar places at the back of the beuch, so that there are eight miets in all. The air passing through the various series of horizontal flues is kept entirely distinct from the air travelling in the adjoining series ; thus the supply to the various portions of the combustion chamber is under control. The waste gases, after leaving the setting, pass vertically downwards, and are kept in separate streams until th.ey reach the bottom of the regenerator flues, when th.ey enter a common channel. At the bottom of each. separate compartment a damper enables any one of the streams to be controlled. In the illustration given, the amount of direct contact surface be-tween the waste-heat and the second-
ary-air flues is 434 square feet.
An illustration of the Winstanley regenerator is given in Fig. 49. The chief point to notice about this type is
that the secondary air is taken in in two distinct streams, one on each. side of the waste-gas channel, so that the maximum heat is extracted from the hot products. It will be noticed that the inner stream of secondary air is sandwiched between the waste gases and the producer, whilst primary air is admittecl through, side channels.
It is a striking faet that few standard English settings embrace facilities for heating the primary air as well as
Fig. 49.—Winstanley Retort Setting, showing System os Regeneration.
the secondary. Such, systems are more frequently met with on the Continent, where many complicated arrangements are introduced. From an analysis of fuel results, however, it appears that attention to the practical points of design is of greater valne than purely theoretical refinements.
The South Metropolitan Gas Company, as is well known, employ generator set-tings almost exelusively; but at their Old Kent Road works they have adopted a
regenerator of their own design. A section of this is shown in Fig. 50. It will be noted that the producer gas, supplied from outside producers, is delivered to the combustion chamber by a series of vertical flues, oval in section, and numbering eight to each setting. At the same time, the secondary air is admitted through vertical Doulton-ware tubes, around the exterior of which the waste gases travel.
(/) The General Arrangement of the Setting
This is, in the first instance, entirely dependent upon the capacity of the unit in question. Small works have, of course, to take up the small fluctuations in