Valve Types and Applications–I

Ball Valve

A ball valve is a quarter-turn valve with a port ball that can be rotated in the pipe to prevent or allow fluid flow. The special design can achieve a certain degree of flow regulation. The main specifications include the number of ports, port configuration, port connections, valve size, and the materials that make up the body, ball valve seat, seal and stem packing.

From compressed air pipelines to high-pressure hydraulic system, ball valves are used at any place where fluid flow must be cut off. Ball valves can provide low head loss characteristics because the ports can accurately match the pipe diameter. The sealing performance of the ball valve is better than that of the butterfly valve, but the purchase and maintenance cost is higher. Usually, ball valves are driven by a lever that provides a visual indication of the valve status.

Butterfly Valve

The butterfly valve is a quarter-turn valve with a centrally mounted circular disc that can be screwed in or out of the water flow. The main specifications include port connection, valve size and materials that make up the valve body, valve seat, seal, ball valves of the same capacity, and are difficult to operate under high pressure and flow. They are also more prone to leaks than ball valves and have higher head losses.

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How Does a Ball Valve Work?

Ball valves can have multiple ports, which are the openings in the valve. Two-way ball valves have two ports and are used for traditional on/off control. Multi-port valves (3-way, 4-way, etc.) are used in applications that require more than one source of media or that need to divert media in different directions.

The port of a ball valve can be opened or closed to control media either manually or through actuation. The manual option requires handles or levers and an operator to control the valve. Electric, hydraulic and pneumatic actuation don’t require an operator to control the valve. Actuation is ideal for complex control systems or those that are in remote areas that an operator cannot easily access.

Benefits of Ball Valves

Compared to other types of valves, ball valve offer several notable advantages:

• Compact, economical designs
• Fast shut-off speeds
• Durable in high-pressure, high-volume and high-temperature applications
• Less prone to corrosion or damage
• Long service life
• Versatile and ideal for a range of industrial applications

Applications That Use Ball Valves

Ball valves are used everywhere from around the home to specialized industries. Here’s a look at a few examples:

Home applications:

• Washing Machines
• Outdoor Hoses
• Dishwashers

Specialized industries:

• Oil & Gas
• Food & Beverage Equipment
• Automotive
• Vehicle Wash Systems
• Power Processing
• Pharmaceutical
• Chemical Admixtures & Treatment
• Irrigation & Water Treatment Equipment
• Manufacturing Facilities

Parts of a Ball Valve

Ball valves are constructed with several crucial components:

• Valve Body
  This is the main part of the valve and contains all of the components for on/off control.
• Rotary Ball
  The ball is designed with a center bore (hole) that the media flows through. The direction of the ball is controlled by turning the stem.
• Stem
  This connects the ball to the external control mechanism. For example, in a manual ball valve the stem is connected to a handle or lever.
• Seats
  These are discs that lie in between the body and the ball. Seats provide a seal between the two and also support the ball.
• Power Source
  The stem of the ball valve is rotated using manual or actuated power sources. Manual actuation includes levers and handles that are controlled by an operator. Automated power sources like electric, pneumatic and hydraulic actuation are also available.
• Packing
  This is a seal around the stem that prevents the media from escaping.
• Bonnet
  The bonnet is the part of the body that contains the stem and packing.