STOP-COCKS OR TAPS.
FIG. 1.
FIG. 4.
FIG. 2.
FIG. 3.
FIG. 5.
Taps are used for the purpose of letting off or stopping at pleasure the flow of liquids from vessels or through pipes. The forms of stop-cocks are very various, but the form shown at [fig. 1] is by far the most general; it consists of a short curved tube, having an upright cylinder in the centre in which a plug with a handle turns; this plug is perforated in the direction of the length of the handle, so that when this is turned crosswise the communication is shut off ([figs. 2], [3], and [4]). The “nose” or end of the tap is sometimes prolonged into a spout, for filling bottles, &c., as in [fig. 5].
FIG. 6.
FIG. 7.
FIG. 8.
FIG. 9.
FIG. 10.
FIG. 11.
The safety tap differs somewhat from the ordinary tap, a section is seen in [figs. 6] and [7]; the plug is hollow and forms the nose or spout itself, this plug is only perforated on one side, so that it has to be turned round half-way instead of quarter-way as in the common tap. The upper part of the cylinder has an opening (of different shapes) leading to the top of the plug, &c., a key being made to fit it ([fig. 9]). The American wooden taps ([fig. 8]), are just like it, but have the handle united instead of a key. The four-way tap is a clever contrivance for uniting four passages in alternate pairs; [figs. 10] and [11] indicate the different positions of the plug. This kind of tap was formerly an important part of the steam-engine, and allowed the steam alternately to enter above and below the piston.