A basic idea about the valve and its types

We have come across pipes everywhere that efficiently transport large amounts of liquids and gases (collectively called fluids). But they need a regulatory body to decide the amount of flow and to start and stop the flow for its efficient operation. Here, the valves come into the picture and are the regulating body that controls the flow rate and acts as a switch to start and stop the flow.

Valves are mechanical devices that totally or partially obstruct pipes or the passage of liquids and gases to control the flow as required. In our lives we come across many valves on a daily basis, but we may never have noticed them. The taps that we open and close to control the flow of water is a valve. The regulators we use to control the flow of gas in our pipelines are also valves. There are also gas control valves in our kitchens. These valves are not limited to man-made things, but are found naturally and also in our bodies. Our heart has valves that help regulate the flow of blood in our body.

The valves are made of plastic or metal and can be controlled by handles, levers, pedals and wheels or can be controlled automatically. Generally, the outer parts are metal or plastic and are called the seat and the inner part generally has plastic and rubber valves for effective control of fluid flow. The body is the inner part of the valve that fits into the seat and controls the flow by opening and closing partially or fully, depending on the flow requirements.

Ball valves are usually quarter turn valves (since we turn the lever 90 degrees to start or stop the flow) and we use a hollow, perforated, pivoting ball which is also called a floating ball. It is through this valve that the flow of fluids takes place. When the lever or handle is turned 90 degrees, the hole in the ball lines up with the opening in the pipe and flow begins. When the lever is turned 90 degrees again, the orifice rotates and the ball blocks the pipe opening, causing the flow to stop.

There are many types of ball valves that are widely used in various industries based on their designs, sizes, and pressure handling capabilities. Full port, reduced port, cavity fill, V port, stump ball valves and multiport valves are the most common.

Full port valves are used when there is a requirement for free flow of fluids. This valve has an oversized ball with a large orifice to allow large quantities to flow through it. But when there is a high pressure requirement in the flow, reduced port valves are preferred. A common example is the pipe heads used for a car wash. As we require pressure in the water flow, this type of valve is used in them. Trunnion ball valves have a disc or anchor above and below the valve generally suitably shaped when there is a high pressure and large flow requirement.

Valves have played an important role in fluid transportation in various industries such as oil and petrochemicals, pharmaceutical industries, and the food and beverage industries, and they have also become vital parts of many types of machinery.