If your plumbing experience has been limited to turning a faucet on and off, you may be pleasantly surprised at the simplicity of the system behind that faucet.
Home plumbing is largely a network of pipes and the fittings that connect them, carrying water in and out of the house by two basic forces of nature: pressure and gravity. Water fixtures'sinks, tubs, showers and toilets'and such appliances as dishwashers and washing machines tap into this system, receiving fresh water from one set of pipes and discharging used water through another.
Here's a first look at the basic terms and concepts you'll need to know when evaluating, repairing, or extending your home's plumbing system.
The water cycle
Plumbing is closely tied to both weather and geography. Water that enters your home starts way up in the sky, falling to earth as rain or snow. It flows in a stream or river to a lake or manmade reservoir or percolates down into the water table'which is like a river or lake, only underground. The water then travels through a treatment plant, pumping station, and/or local water tower to a water main and meter or from a private well that taps into the local water table. Fresh water enters the house via a main cold water pipe and flows, under pressure, out of whatever faucet has been turned on.
Where does used water go? So-called 'gray water' and waste leave the house and head for the city sewer or a private septic system. This sewage moves by gravity'each point in the system is at a lower slope than the one preceding. From the city sewer, water goes to a treatment plant, which removes waste from water, or to a septic tank, which does the same thing. Water evaporates back ino the sky, where things start all over again.
Three plumbing systems
Now let's peek inside the house. There are really three separate but interdependent pipe systems: supply, drain-waste, and vent. (Drain-waste-vent systems are interconnected and therefore often referred to as the 'DWV system.')
The supply system carries pressurized water from a utility main or private well into your house and around to all the water-using fixtures and appliances. What drives this pressure? There's either an initial 'fall' (such as from a water tower) or a 'push' from a pumping station; displacement does the rest. Because the water is in a closed supply pipe system, it has nowhere to go but along the same path, pushed along by the water behind it. When you open a faucet or valve, water flows out; when you close it, the flow stops until the next time you open it.
The drain-waste system transports gray water and waste out of the house into a city sewer or septic tank outside the house perimeter. Tub and sink drains flow by gravity only; toilets use a combination of pressure (falling water) and gravity. If waste needs to flow uphill at any point, such as from a basement bathroom, an electric pump helps push it up.
The vent system carries away noxious sewer gasses. When a drainpipe is empty, sewer gasses rise up the vent pipe and out the roof. P- or S-shaped pipe bends, called traps, below each drain remain filled with just enough water to prevent sewer gasses from seeping out the drain into your home. The vent system also helps maintain atmospheric pressure in the drain system to help wastes flow downhill. It works on the same principle as the second hole on a gas can.
By : HomeTips.com
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