A quarter-turn valve, such as a ball valve, is simply a ball put in a passageway through which fluid flows. The valve opens and closes by passing through a hole in the ball. The fluid flows through the ball as it is placed so that the hole runs in the same direction as the passageway, and the valve is opened. The ball may also be placed with the hole perpendicular to the passageway, preventing fluid from passing through and closing the valve. It’s usually operated from the outside, with a handle that can be rotated back and forth to open and close the valve.
What exactly is a ball valve?
The majority of ball valve actuators are quick-acting, requiring a 90° turn of the valve handle to operate. Planetary gears are used to control other ball valve actuators. This form of gearing enables the operation of a large valve with a small handwheel and operating power.
Aspherical surface coated plug that is off to one side in the open position and rotates into the flow passage until it fully blocks the flow path that has been created for some ball valves.
The eccentric movement of the plug allows for seating. The valve does not need to be lubricated and can be used for throttling.
Ball valves come in three different sizes. A full port valve has no flow restriction, meaning liquid can flow freely through it when it is open. This is accomplished by making the ball larger than the passage size, allowing the hole to match the passage size. Since a typical port ball valve lacks an oversized ball, the hole is one size smaller than the passageway. When the fluid flows through, this causes a slight flow limit. On the other hand, reduced port valves have a smaller ball and even smaller opening, resulting in considerable flow restriction as the fluid flows through them.
Patterns of Ports
Ball valves come in three different patterns: venturi, reduced, and full port. A ball with a bore equal to the pipe’s inside diameter is used in the maximum port pattern.
Materials used in valves
Balls are normally made of metal with elastomeric (elastic materials that resemble rubber) trim (seats). There is also a plastic construction option.
The elastomeric material is used to make resilient seats for ball valves. Teflon (TFE), filled PTFE, Nylon, Buna-N, Neoprene, and these materials’ variations are the most popular seat materials.
These valves cannot be used at high temperatures due to the elastomeric materials. The seat material must be chosen with care to ensure that it is consistent with the valve’s materials.
Design of a Ball Valve Stem
A ball valve’s stem is not attached to the ball. At the ball end, it usually has a rectangular section that fits into a slot cut into the ball. The enlargement allows the ball to rotate as the stem is rotated.
Style of a Ball Valve Bonnet
The stem assembly and ball are kept in place by a bonnet cap that attaches to the body. The packing that supplies the stem seal can be compressed by adjusting the bonnet cap.
Ball valve stem packing is usually made up of die-formed packing rings made of TFE-filled, TFE, or PTFE-impregnated material. O-rings, rather than packing, are used to seal certain ball valve stems.
Place of the Ball Valve
Some ball valves have stops that only allow for 90° rotation. Others have no stops and can be rotated 360 degrees. A 90° rotation is all that is needed to close or open a ball valve, with or without stops.
The handle indicates the location of the valve ball. The valve is open when the handle is parallel to the axis of the valve. The valve is locked when the handle is 90 degrees around the axis of the valve.
A groove is cut into the top face of certain ball valve stems to reveal the ball’s flow path. The position of the groove in the ball can be determined by looking at it. On multiport ball valves, this function is particularly useful.
1 It has a compact structure, is light in weight and length, and is simple to disassemble and fix.
2 The packing seal of the valve stem is not easily broken because it rotates, and the sealing capacity increases as the medium pressure increases.
3 The fluid resistance is mild, and the flow resistance of the full-bore ball valve is virtually non-existent. Pneumatic ball valves have one of the lowest fluid resistance ratings of any valve type.
4 The process is easy and fast, and it only requires a 90-degree rotation from full opening to full closing, making it ideal for long-range control.
5 It can be used in various applications, ranging from a few millimeters to a few meters and from high vacuum to high pressure.
A sanitary ball valve’s operating theory is identical to that of a normal ball valve because the production materials and procedure are more stringent.
Precautions to take before using
1 Once a year, the ball valve should be cleaned and fixed.
2 To prevent the ball from being trapped, the ball valve should be triggered at least once a month.
3 Throttling is not possible with the ball valve since it can either be completely open or fully closed.
Because of this valve’s design, it is ineffective in circumstances where fine control is needed, such as the throttle control valve in a car. It performs admirably in circumstances where a flow must be fully stopped, such as the shut-off valve on a home’s main water line. Ball valves often don’t develop problems if they’re not used for a long time; when they’re needed again, they’ll work flawlessly.
Adamant Valves, a global sanitary valves supplier and valves manufacturer, was established in 2002 and has since evolved to become one of the top valves manufacturers for high precision pumps, stainless steel sanitary valves, and pipe fittings.