Guide to Choosing the Right Valve eBook

All valves typically contain the following components:

• A body, which contains the internal parts.
• A port, which allows the fluid to pass through the valve.
• A handle (if a manually-controlled valve) or an actuator (for automatically-controlled valves).
• A stem, which transmits motion from the handle or the valve’s controlling device to form a leak-proof seal.
• A disc or similar valve component that serves as a moveable obstruction to adjust the flow of the fluid through the valve.
• A seat, which is the interior surface of the body that contacts the disc to form a leak-tight seal.

Types of Valves

BALL VALVES

How it works: Ball valves control the flow of a material or substance from one opening to the next. These are quarter-turn valves that use a hollow, perforated, and pivoting ball to control the flow of fluid through the valve. The valve is open when the valve’s hole is in-line with the fluid, and closed when the ball is rotated 90 degrees by turning the valve’s handle.

There are a couple of variations on ball valves that may be used for specialized applications. There are 3-way ball valves on the market, for example, that can be used as flow divert valves. These are popular because they provide a simple and economical method to provide both shutoff and flow direction control in a single valve body.

There’s also a valve called a characterized ball valve that features a V-notch in the ball itself. These particular valves provide a more precise flow control compared to standard ball valves. The v-shape in the ball enables the valve to convert to a modulating control ball valve.

Used for: Water, clean or 3-A air, culinary steam, and in food & beverage processing, non-viscous fluids not requiring CIP cleaning (e.g., vinegar, some sugars). Can be used with corrosive fluids and a wide variety of gases, as are typically found in the oil and natural gas industries.

Construction: Stainless steel, brass, bronze, chrome, titanium, PVC, CPVC, and many other materials.

ADVANTAGES

• Compact, durable, and reliable.
• Requires little maintenance.
• Relatively inexpensive in comparison to other valves.
• Comparatively leak-proof.
• Opens and closes relatively quickly (depending on the type of actuator)
• Suitable for high temperature and high pressure applications (up to 700 bar pressure and 200 degrees Celsius).

DISADVANTAGES

• Lacks fine control. Really just suitable for on/off applications, not fluid throttling or flow regulating.
• Not a sanitary valve. Product can become trapped in the ball area when the valve is closed.
• Cannot be cleaned using CIP methods.

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