RETORT-BENCH APPURTENANCES
245
of the faced rim than at others, this being an objectionable but unavoidable feature of the appliance.
The means employed for attaching the mouthpiece to the retort is of consider-able importance, as an insecure joint soon gives way under the stresses of the stoking
Fig. 143.—Sele-sealing- Retobt Lid, showing Pbinciplb or Action.
Fig. 144.—Detail of Tightening Handle, showing Eccbntrics.
machinery and pipe augering. There are three distinct methods now made use of for affixing the mouthpiece. The most common method (Fig. 145) is to cast the mouthpiece with a plain back flange, the flange being drilled at intervals for bolts, which. are secured. in slots in the thickened end of the retort. In this case some form of jointing material must be used between the flange and fireclay end of the retort, for which. parpose the following usually gives the best results: One part of cast-iron borings to 2| parts of fireclay, the mixture being just damped with a solution of sal ammoniac. The amount of sal ammoniac required is about 1 Ib. to every hundredweight of the fireclay and borings. For this purpose sal ammoniac is to be preferred to ammoniacal liquor, as a more complete rusting action is set up.
Fig. 147.—C.I. Sheath. Fig. 148.—Shbath and Mouthpiece combined.
Mouthfieces to Retobts.
Fig. 145.—Oommon Bolt Attachment.
Methods of Attaching
Fig. 146.—Shbath Attachment.
A comparatively recent method of attachment is that shown. in Fig. 146, in which. a distinct sheath or socket is employed. The socket (Fig. 147) is made from cast-iron, usually f-inch thick throughout, and is passed completely over the end of