But the beginnings of the modern tap was much more different than it is today. The innovation of mixing the two lines was revolutionary when it was patented in 1880 by Thomas Campbell. The standard faucet is a mixer tap. This requires both hot and cold water lines to combine before reaching the outlet and there are multiple tap types and forms.
A bibcock is a mixer tap with a downward bent spout.
Higher end spigots incorporate a pressure balance feature. This feature allows the hot and cold water ratio to remain consent and unaffected by changes in water pressure due to extraneous causes. Such water loads may occur when an individual flushes the toilet or does a load of laundry. This prevents scalding or chilling from occurring.
The valve that has the function of mixing waters is one of the most important parts of a faucet. There are four (4) main types of faucet valves; compression, cartridge, ball valve and disc.
The most common location where you can find a compression valve in your current home would be in the laundry room or your outside spigot. These are typically standard screwable faucets that are connected to a single water line. Two handles/valves, one cold and one hot, are needed to provide a mixing function. This valve works like a screw and compresses a washer against a valve seat. These faucet valve types tend to be the least expensive and prone to leaks and will need maintenance. Failure problems occur when the valve seat cracks, the washer wears out, or mineral deposits accumulate on the valve seat inhibiting a water-tight seal.
It can be difficult to determine a compression faucet from a cartridge faucet. When this occurs, you physically have to turn the controls to determine which valve tip it is. A compression valve will require you to turn the knob far enough to shut the water off. A cartridge valve will not require a 'turn until it stops' mentality. They will have a clearly defined off position and not require additional work to be done.
Ball valve faucets are the most common single handle faucets. unlike the compression valve, ball valves are capable of mixing water temperatures. Multiple holes within the ball provide hot and cold water to flow through different inlets and combine for the desired washing temperature.