Valves can be used to control the pressure and direction of water, to ensure that there is no backflow, to direct water to and from a fixture and to prevent cross-connections in the plumbing system.
There are various kinds of valves used in plumbing that offer varying levels of control. Some valves operate by themselves mechanically while some need to be regulated externally.
Different kinds of valves have their own advantages and disadvantages, making them suitable for different purposes.
Gate valves are one of the simplest forms of plumbing valves. Gate valves provide a mechanism to start and stop the flow of water completely, though they cannot be used to regulate the flow of water beyond that.
The valve has a diameter that is the same as the pipe it is fitted into. The valve has a ‘gate’ which is a disk or wedge of metal. When the valve is opened, the gate of the valve is pulled up completely in the valve, thus allowing for the full flow of water.
When the valve is closed, the gate of the valve is pushed down and the flow of water is completely stopped.
There are two kinds of gate valves, one in which the external handle of the valve is pushed up and down along with the gate of the valve.
This kind of gate valve will allow you to understand whether the valve is open or closed by looking at it, but there might not be enough space for it in confined spaces.
Another kind of gate valve has a handle that does not rise with the gate of the valve.
Butterfly valves are used to regulate the flow of water. They consist of a disk that has the same diameter as the pipe into which it is fitted. An external handle is used to rotate the disk to allow different amounts of water to pass through.
The disk of the butterfly valve remains in the pipe even when it is completely open. As a result, installing a butterfly valve in a pipe results in a reduction in the flow of water by default.
Butterfly valves are extremely compact, lightweight and affordable, which is why they are used in spite of their disadvantages.
Ball valves are the most commonly used kind of valve. They consist of a spherical mechanism like a ball that has a hole in the center. When the valve is opened, a handle is used to align the hole in the ball with the opening of the pipe so that water can pass through.
When the valve is closed, the hole of the ball is perpendicular to the pipe so the flow of water is completely stopped.
The external lever makes this type of valve convenient because the position of the handle serves as an indicator of whether or not the valve is opened.
The handle of the ball valve can be used to open it partially, a quarter of the way or half the way as well. This is done through stops at 45 and 90 degrees respectively.
Though ball valves cannot be used to control the flow of the water in a very precise manner, they are commonly used because they offer the functions of a gate valve at a more compact size.
Globe valves are used to restrict the flow of water. Globe valves consist of a stopper that is connected to a twist knob using a stem. The knob is twister to lower or raise the stopper.
The stopper goes down and connects to a baffle in order to stop the flow of water completely. However, the baffle remains inside the pipe even when the valve is open and hence there cannot be a completely unrestricted flow of water when a globe valve is installed in a pipe.
Globe valves are fairly simple to operate and they do not give in to wear and tear, even when used regularly. Thus they are the choice of valve for plumbing setups where the flow of water needs to be adjusted regularly.
Check valves can have different designs, but they have the common function of checking the flow of water in undesirable directions.
In any plumbing system, there is one stream that consists of the supply of water. Another stream is the drainage system which takes the wastewater to the sewage.
Backflow of water can result in the mixing up of these two streams. A check valve is used to stop the backflow of water.
Non-operational check valves have a mechanical design that works automatically without the need for any operator.
For instance, some check valves can have a spherical object like a ball which blocks the opening of the pipe when the water flows in the wrong direction. This is known as a ball check valve.
Check valves can also have flaps or disks that are pushed to block the pipe by the backflow of water. These are known as diaphragm check valves.
There are also operational check valves that work automatically to stop the backflow of water but can also be manually operated to stop the flow of water in any direction.
These are known as stop check valves and they can be used to block the flow of water even when it is in the correct direction. These can be especially helpful when you need to stop the flow of water in order to inspect or repair parts of the plumbing system.
Valves are important components of any plumbing system as they are used to control and regulate the flow of water.
Some valves are used to stop and start the flow of water completely while some can be used to partially restrict the flow of water according to your needs.
Some valves also operate automatically through their mechanical design to stop the backflow of water and allow the water in the pipe to only flow in the desired direction.