We have come across pipelines all around that efficiently transport vast amounts of liquids and gases (collectively called as fluids). But they need a regulating body to decide the amount of the flow and to start and stop the flow for their efficient working. Here, valves come into picture and are the regulating body that control the flow rate and act as a switch to start and stop the flow.
Valves are mechanical devices that obstruct pipes or passages of liquids and gases either wholly or partially to control the flow rate as required. In our lives we come across many valves daily, but might have never noticed them. The taps that we open and close to control the flow of water is a valve. The regulators that we use to control the flow of gas from our gas pipelines are also valves. There are gas control valves in our cookers too. These valves are not limited to man-made things, but are found naturally and that too in our bodies. Our heart has valves that help in regulating the flow of blood in our body.
Valves are either made of plastic or metal and can be controlled either by handles, levers, pedals and wheels or can be controlled automatically. Generally, the exterior parts are either metal or plastic and are called seat and the inner part generally has plastic and rubber valves for an effective control of the flow of fluids. Body is the inner part of the valve that fits on the seat and controls the flow by opening and closing either partially or wholly depending upon the requirement of the flow rate.
Ball valves are usually quarter turn valves (as we turn the lever by 90 degrees to start or stop the flow) and use a hollow, perforated and pivoting ball that is also called as a floating ball. It is through this valve that the flow of fluids takes place. When the lever or handle is turned to 90 degrees, the hole of the ball gets aligned with the pipe opening and starts the flow. When again the lever is turned by 90 degrees, the hole turns around and the ball blocks the opening of the pipe thus causing the flow to stop.
There are many types of ball valves that are extensively used in various industries depending upon their designs, sizes and pressure handling capacities. Full port, reduced port, cavity filler, V port, trunnion ball valves and multiport valves are the common ones.
Full port valves are used when there is a requirement of free flow rate of fluids. This valve has an oversized ball with a big hole to allow huge quantities to flow through it. But when there is a requirement of high pressure in the flow, reduced port valves are preferred. A common example is the pipe heads that are used for a car wash. As we require pressure in water flow, this type of valve is used in them. Trunnion ball valves have a disc or anchoring above and below the valve generally suitably when there is a large and high pressure flow rate requirement.
Valves have been playing a major role in the transportation of fluids in various industries like oil and petrochemicals, pharmaceutical industries and food and beverage industries and have become vital parts of many types of machinery too.