Under every sink and wash-basin, and also under the bath-waste outlet, there is a trap consisting of a pipe bent to form a U-bend suitably adapted to the tun of the pipe into the drain. The function of the trap is to hold a certain amount of water in the U-bend, with the object of sealing off the inside of the room from foul air that might otherwise enter from the drain. When the sink or basin is emptied, water runs through the waste pipe and the trap, displacing the water already in the U-bend, but leaving the latter filled up to the requisite level, at the finish of the flush.
At the bottom of the bend there will be found a clearing cap or plug, screwed into a bush incorporated in the lead pipe. Upon unscrewing this cap the contents of the U-bend will run cut, so that a pail or bowl should always be put beneath it at such times. With the cap removed, a bent wire, or a piece of flexible metallic tubing, or thin cane, can be worked into and around the bends to clear any obstruction. This is one way of clearing the trap and the waste pipe, for it is frequently in the trap itself that a blockage occurs.
Use of the Force Cup
Every householder should possess a medium size rubber force cup for emergencies. They cost only a few shillings, and are obtainable at most general stores supplying household equipment. These appliances work on a pressure-and-suction principle. Assuming that the kitchen sink waste runs sluggishly, or not at all, the following procedure should be adopted. Run water into the sink, about two inches deep, then take out the waste plug. Place the force cup over the plug hole. Fill up the overflow hole or holes temporarily with cotton waste or old rags, so that these holes are airtight. Press down firmly with the handle of the cup, so that pressure is communicated to the column of water in the waste pipe and trap. Do this three or four times; as you release the pressure on the handle, try the effect of pulling up the force cup, which will suck up water, and loose pieces of refuse blocking the pipe. By a combination of these actions most blockages can quickly be cleared, either forcing the obstructing matter down the pipe and through the trap, or drawing it up into the sink.
Should this procedure fail to clear the pipe, unscrew the clearing plug from the trap, as previously explained, and try to hook out any blockage with a bent wire. Do not omit to put a big pail below the trap, if much water is in the sink. If the pail fills up, clap the waste plug into the sink outlet for the time, and empty the pail. If the bent wire does not reach far enough, use a flexible metallic tube device (curtain spring wire), working first from the clearing opening in the trap, and then from the grating in the sink. Blockages which do not respond to ordinary treatment may be loosened by emptying the sink and trap, and then filling the sink outlet through the grating with washing soda; pour boiling water down to dissolve the soda, and wait awhile before again endeavouring to clear the obstruction by force cup. A good precaution against the occurrence of obstinate obstructions in the waste pipe is to use the force cup whenever the waste water tends to drain away sluggishly.
Baths and Lavatory Wastes
The procedure here is the same as for sinks; try the force cup first. Bath traps are sometimes hidden behind the panel enclosing the side of the bath, more particularly in modern type baths, and are less accessible to the use of a flexible tube. Regular use of the force cup is therefore recommended, to make sure the flush through is complete and effective. However, use the ‘flexible tube as required, and probably it will not be necessary to open the clearing cap at the trap. In the case of wash-basins, regularly inspect and remove any hair and odd scraps of soap, which often collect on the grating of the waste outlet. This simple precaution will prevent the occurrence of obstinate obstructions in the drain pipe. Really hot water poured down occasionally, with or without broken soda filled into the opening, will dissolve congealed soap which has collected below, a frequent nucleus of obstructions. This remedy is inadvisable during exceptionally cold weather, as the basin may be cracked by the sudden change of temperature.
Traps to Gulleys
Every drain gulley outside the house, into which a waste pipe or rainwater pipe empties, has or should have a trap incorporated, to seal it off. However, in the summer months a neglected gulley may give off an offensive odour and regular cleansing is required. The iron grating should be lifted and the trap cleansed of sludge. A bucket of clean water to which has been added enough crystals of permanganate of potash to colour the water a deep pink should be thrown down the gulley at least once a week in hot weather.