Part 13 (1/2)

First.--Generators with internal vaporizers, such as the Otto Deutz and Wiedenfeld generators.

[Ill.u.s.tration: FIG. 92.--Old type of Winterthur producer.]

Second.--Generators with external vaporizers, such as the Taylor, Bollinckx, Pintsch, Kinderlen, Benz, Wiedenfeld, Hille, and Goebels generators.

=Cylindrical Body.=--The generator consists essentially of a mantle made of sheet-iron or cast-iron and containing a refractory lining which forms a retort, a grate, and an ash-pit. In the small size apparatus the cast-iron mantle is often used, whereas in large sizes the mantle is made of riveted sheet-iron so as to reduce its weight and its cost. In the latter case the linings are securely riveted or bolted.

The Winterthur generator (Figs. 92 and 93), the Taylor generator (Fig.

94), and the Benz generator (Fig. 97), are made of cast-iron; the Wiedenfeld generator (Fig. 95), the Pintsch generator (Fig. 96), are made of sheet-iron; the Bollinckx (Fig. 98) is made partly of sheet-iron and partly of cast-iron.

The different parts of a generator, if made of sheet-iron, are held together by means of angle-irons forming yokes, and a sheet of asbestos is interposed. If the parts are made of cast-iron, they are connected after the manner of pipe-joints and packed with compressed asbestos.

This latter way of a.s.sembling the parts presents the advantage of allowing them to be dismembered readily. Therefore, it allows the several parts to expand freely and facilitates the securing of tight joints. This last consideration is exceedingly important, particularly for the joints which are beyond the zone in which the distillation of the fuel takes place. Any entrance of air through these joints would necessarily impair the quality of the gas, either by mingling therewith, or by combustion. The air so admitted would also be liable to form an explosive mixture which might become ignited in case of a premature ignition of the cylinder charge during suction or through some other cause.

[Ill.u.s.tration: FIG. 93.--New type of Winterthur producer.]

[Ill.u.s.tration: FIG. 94.--The A. Taylor producer.]

[Ill.u.s.tration: FIG. 95.--Wiedenfeld producer.]

[Ill.u.s.tration: FIG. 96.--Pintsch producer.]

[Ill.u.s.tration: FIG. 97.--Benz producer.]

[Ill.u.s.tration: FIG. 98.--Bollinckx producer.]

[Ill.u.s.tration: FIG. 99.--Lencauchez producer.]

=Refractory Lining.=--The interior lining of the generator should be made of refractory clay of the best quality. It would seem advisable, in order to facilitate repairs, to employ retorts made of pieces held together instead of retorts made of a single piece. In the first case the a.s.sembling should preferably be made by means of refractory cement, and the inner surface should be covered with a coating so as to form a practically continuous stone surface.

[Ill.u.s.tration: FIG. 100.--Goebels producer.]

Some manufacturers, in order to allow for the renewal of the part most liable to be burnt, employ at the bottom of the tank a refractory moulded ring (Lencauchez, Fig. 99).

It is always advisable to place between the sh.e.l.l or mantle of the generator and the refractory lining a layer of a material which is a bad conductor of heat as, for instance, asbestos or sand, in order to avoid as much as possible loss of heat due to external radiation (Fig. 100).

[Ill.u.s.tration: FIG. 101.--Pierson producer.]

=Grate and Support for the Lining.=--These parts, owing to their contact with the ashes and the hot embers, are liable to deteriorate rapidly. It is therefore indispensable that they should be removable and easily accessible, so that they may be renewed in case of need. From this point of view, grates composed of independent bars would appear to be preferable. The clearance between the bars depends, of course, on the kind of ashes resulting from the different grades of fuel. It is advisable to design the grate so that the free pa.s.sage for the air is about 60 to 70 per cent. of the total surface.

In generators having a cup-shaped ash-pit, containing water (Fig. 95), the grate and the base of the retort are less liable to burn than in apparatus having dry ash-pits. Certain apparatus, such as those of Lencauchez (Fig. 99), Pierson (Fig. 101), and Taylor (Fig. 94), have no grates; the fuel is held in the retort by the ashes, which form a cone resting on a sheet-iron base, easy of access for cleaning and from which the fuel slides down gradually.

The Pierson generator (Fig. 101) is provided with a poker comprising a central fork, which is worked with a lever, in order to stir the fire from below without entirely extinguis.h.i.+ng the cone of ashes.

In some apparatus in which a grate is used (Fig. 92), a s.p.a.ce is left between the grate and the support of the retort. This arrangement has the merit of allowing only finely divided and completely burnt ashes to pa.s.s to the ash-pit. Moreover, a large surface grate can be employed, thus facilitating the pa.s.sage of the mixture of air and steam.

[Ill.u.s.tration: FIG. 102.--Kiderlen producer.]

The s.p.a.ce above mentioned is provided with a cleaning-door through which cinder and slag may be removed.

In other apparatus the grate rests either on the support of the refractory lining, as in the old type invented by Wiedenfeld (Fig. 95), or upon a projection embedded in the lining, as, for instance, in the Kiderlen (Fig. 102) and Pintsch generators (Fig. 96).

In the Riche apparatus (Fig. 103) there is, besides the ordinary grate, a grate with tiers on which the fuel spreads. This grate consists of wide, hollow bars containing water. It should be noted that the apparatus is of the blower type.