Baths and lavatories are of very numerous variety; but a good feature with a bath is to have the hot-water inlet near the bottom, so that when the taps are opened this inlet quickly becomes below the water level, and this prevents the steam rising as the water is discharged, rendering the room unbearable if small; but this inlet must not be in any way connected with the waste outlet as it often is, as when the water runs in it will bring back a portion of the last bather’s soapsuds. A good feature in a lavatory basin is a flushing rim: the rim of the basin is hollow and provided with a fine slit or aperture which extends all round its lower edge. When the tap is turned, the water is discharged into this rim, and from there flows into the basin, through this aperture around the whole of its circumference; this is of especial use to wash away sediment from the sides of the basin after use.
Both baths and lavatories should have large supplies (hot and cold) and large wastes, to fill and empty rapidly.
No. 2 system can, when desired, be converted into No. 1 system at a moderate expense (about one-third the cost of a new apparatus); and a range can be fitted with a high-pressure boiler in such a manner that it can be used for low-pressure purposes first, and when the high-pressure apparatus is fitted up it can be connected and started to work upon the latter principle in 2 or 3 hours.
If two ranges are in proximity they can both be provided with high-pressure boilers and the two services united, flow to flow and return to return, and work the one tank or cylinder and apparatus, either assisting each other or working independently. This is oftentimes a very great convenience; the union of the services should be as near the boilers as possible; no stop taps are needed (avoid these whenever possible).
Twin boilers can sometimes be fitted to a range, and each used for a different purpose, viz. one for hot-water supply, and one for steam cooking, &c.
133. Self-filling Apparatus.
Fig. 133 represents the common form of self-supply or self-filling apparatus as attached to low-pressure boilers in kitchen ranges. By the term “low pressure” is meant open top or closed boilers that are not usually filled quite full, and the draw-off is below the water-level within them. A represents the small supply cistern, which is supplied from the general cold supply of the house; the quantity and level of the water in this small cistern is regulated by a ball valve D, as shown; this cistern is connected with the boiler B by a supply pipe C, usually of lead and ¾ inch internal diameter, and provided with a “syphon” as shown, and for the purpose described in cold supply to tanks, &c.; this supply proceeds from the bottom of the supply cistern A to the bottom or near the bottom of the boiler B. There is a very common error in arranging the apparatus so that the boiler fills up to about 4 in. from the top; this is not high enough, it should fill up to within about 1½ in., this is ample room for expansion and boiling; if a 4 in. space is left it means 4 in. for the flame and heat to act upon without having water to protect it, and consequently it becomes destroyed. This does not always produce a leakage, but it permits the smoke and soot to enter and discolour the water. There is another still more common form of error in this description of apparatus, and that is, failing to draw from the upper part of the boiler where the hottest water is, and where it first becomes hot; it will be understood from Fig. 133 that when the tap (if placed near the bottom of the boiler as usual) is opened, a portion of the contents of the boiler flows out and a supply of cold immediately flows in, to make good the loss. Now the hot water being lightest, remains at the top of the boiler, so it can readily be seen that it cannot be drawn, for it will not descend, and the inflow of cold is right opposite the tap, therefore when the tap is opened a small quantity of hot water is drawn, and then there sets in a flow of cold water from the cistern, across the bottom of the boiler, and out at the tap almost without disturbing the hot water in the upper part of the boiler. There are two remedies; one is to have the tap inserted in the upper part of the boiler (by the manufacturer) when purchasing it; another is with existing ranges to screw an elbow on to the end of the tap inside the boiler, and into this elbow to screw a short length of pipe to stand up to about 4 in. below the water-level, as in Fig. 134; this elbow and pipe can be fitted by any one, as no jointing is required, and to fit it the tap does not require to be moved in any way. The reason that it is necessary to keep the end of the pipe so much below the water-level is, that the ball valve by which the cold water is supplied is smaller than the tap from which the water is taken, or, in other words, the inlet is smaller than the outlet, and the level of the water sinks or becomes lower in the boiler and cistern as you draw.
134. Draw-off Tap.