CHAPTER VIII
RETORT-BENCH APPURTENANCES
The retort-bench fittings employed with modem horizontal settings do not vary in character to any marked extent. Various engineers employ different means for arriving at the same end; but the distinction in most cases is generally a mattei* of detail. In the first place, th.e chief items requiring consideration. are—
1. (a) The primary staying-up of the bench (i.e., by longitudinal and transverse buckstays and ties).
(6) The secondary staying-up of the individual setting, such, as cross-bracing between the buckstays to prevent protrusion of the regenerators and the producer front. Also the bracing of the front walls above the producer, and the retention, and support of retort mouth.pieces in their correct position.
2. In addition, consideration. has to be given to the various features in the design and erection of the retort inouthpieces, ascension pipes, bridge pipes, hydraulic mains, etc., so that th.e process of gasnaaktng may proceed with. the regularity essential to the best results.
RETORT MOUTHPIECES
The self-sealing metal-to-metal retort door is now in almost universal use, except in the smallest of works making less than about 6 to 8 million cubic feet of gas per annum, which., for the sake of convenience, still adhere to the detached door with. spent lime luting and central-tigktening hand-screw. For small stop-ended retorts this method is advisable, particularly in cases where no facilities exist for readj risting the self-acting type. As the means wherewith. hermetical sealing is obtained in. the common type of door are not always fully understood, a diagram (Fig. 143) is given showing the principle employed. First, the tightening handle is forged with two eccentrics, as shown in. Fig. 144, and the cross-bar passing in front of the lid. turns on these eccentrics. At the same time, whon the tightening handle is tæmed it revolves about the centre of rotation shown. It is thus seen that the eccentrics force the cross-bar towards the lid, and the bar—turning on the fulcrum formed by the clip B—tran smit s pressure to the centre of the door at A. By means of an eccentric bolt, with. which. the cross-bar is attached to the rib of the door at A, wear can be taken up and the pressure regulated. With. the Q -shaped door tlie pressure is not applied at the true centre, hence it is greater at certain portions
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