Ball valves are rotational valves that use metal or ceramic balls with holes in their centers to stop or start fluid flow. As shown in Figure 1, the ball valve opens and closes to allow fluid to flow through it. When the valve handle or stem is turn open, the ball rotates to a point where the hole in the ball is parallel to the valve body inlet and outlet. When the valve is close, the ball is rotate so that the hole is perpendicular to the inlet and outlet of the valve body, thereby stopping the flow.
The majority of ball valve actuators are of the quick-acting type, which requires a 90° rotation of the valve handle or stem to operate. Another type of ball valve actuator is a planetary gear-operate manual, an electrically operate the motor, or a pneumatic piston. An actuator is a device that applies pressure to open or close a valve.
Ball Valve Advantages
The ball valve is often the least expensive industrial valve configuration and has a low maintenance cost. In addition to quick, quarter-turn on/off operation, ball valves are compact, do not require lubrication, and offer tight sealing with low torque.
Ball Valve Disadvantages
In general, industrial ball valves have poor throttling characteristics (except when using a characterized ball, as shown above). Standard ball valves in the throttling position will fail due to the impingement of high-velocity flow and erosive effect on the partially exposed seat.
Ball Valve Port Patterns
Ball valves are available in venturi, reduced, and full port patterns. The ball in the full port pattern has a bore equal to the inside diameter of the pipe.
Ball Valve Materials
In general, balls and bodies are made of metallic materials with trim (seats) made of elastomeric materials such as PTFE (100% virgin polytetrafluoroethylene), RTFE (reinforced Teflon®), TFM, CTFE, Polychlorotrifluoroethene, Polyether Ether Ketone, and UHMWPE. For corrosive applications, ball valve bodies can also be made from various plastics. Care must be taken in choosing the seat material to ensure that it is compatible with the materials being handle by the valve.
Ball Valve Stem Design
A ball valve does not have a stem attached to the ball. The rectangular portion at the ball end normally fits into a slot cut into the ball. This enlargement allows the ball to rotate as the stem is turn.
Ball Valve Bonnet Design
The stem assembly and ball are attached to the body by a bonnet cap. The adjustment of the bonnet cap allows compression of the packing, which provides the stem seal. Ball valve stems are commonly pack with die-formed packing rings made of TFE, TFE-filled, or TFE-impregnated material. There are some ball valve stems that are seal with O-rings rather than packing.
Ball Valve Position
Some ball valves are equip with stops that only allow 90° rotation. Other valves have no stops and can be rotate 360°. A 90° rotation is all that is require for closing or opening a ball valve, with or without stops.
The handle indicates the position of the valve ball. The valve is open when the handle lies along the axis of the valve. The valve is close when the handle is 90° across the axis of the valve. On some ball valve stems, a groove is cut into the top face of the stem to show the flow path through the ball. The groove position indicates the location of the hole in the ball. It is particularly useful for multi port ball valve supplier in Kuwait.
Ball Valve History & Mystery
Ball Valve mystery?
The Ball valve has a checkered history and a somewhat murky origin. This may not be cloak and dagger stuff, but it’s not without mystery… Take a look around to see why the ball valve is so vital. Its use in the petroleum industry, water, electric power, chemical, paper, pharmaceuticals, food, and steel industries, among others. It may seem as if we could not function without the ball valve, and it is probably true! It is a mystery why the ball valve took so long to develop, given how important it is today.
The history of ball valves does not go back to ancient Greece or the American revolution, does it? According to different sources, the modern ball valve was invent around 1957 or in 1967. Is it important when the ball valve was invent? Other than the patented owner, probably not. Even so, the ball valve was still a major advancement over the plug valves of the 20th century. Ball valves became commercially available around 1967. The ruins of Pompeii revealed a bronze tapered plug quarter-turn valve that resembles the ball valves we use today. That’s quite a ball valve mystery, isn’t it?
Ball Valve Birth Pains
It was a spherical ball-type valve patent in 1871 that led to the invention of the ball valve as we know it today. This ball valve had a brass ball and brass seats. There is no evidence that this ball valve storm the market and was not list in valve catalogs of the late 1800s. While today’s ball valve is a relatively recent invention, this ball valve has existed for almost 125 years. In April 1945, the first patent for a resilient seated ball valve was issue. As legend has it, the company’s marketing department couldn’t see a use for the valve, so it wasn’t made. Well, that’s just how the ball valve bounces… Given the large reliance on the ball valve today, I’m not sure why it took so long for people to invent and use it.
