Ball Valve

What is Ball Valve?

Ball valves are quarter-turn on/off devices that uses a hollow, perforated, and pivoting ball to control the flow of liquid or gas through it. It is commonly used in industrial applications to regulate the movement of liquids and gases.

Types of Ball Valves

Ball valves may be classified according to their housing assembly, ball design, and bore profile.

Housing Assembly

  • One-piece Ball Valve

 A one-piece ball valve can also be referred to as single piece ball valve, has a body and end connections formed from a single piece of material. This construction presents a comparatively reduced number of opportunities for leakage. One-piece ball valves are the cheapest ball valves and always have a reduced bore.


  • Split body

A split body ball valve consists of a valve body divided into two or more pieces.

    • Two-piece Ball Valve

Two-piece ball valves are some of the most common ball valves used. As the name suggests, the two-piece ball valve consists of two pieces. The main piece contains the ball and a connection to one end, and the other piece holds the internal components together and has a connection to the other end. The two parts can be dismantled for cleaning, maintenance, and inspection but it requires removal of the valve from the pipe.


    • Three-piece Ball Valve

Three-piece ball valves consist of three pieces: two end caps and a body. The end caps are typically threaded or welded to the pipe and the main body section may be easily removed for cleaning or repair without removing the end caps. This can be a very valuable option because it prevents a line shutdown if maintenance is required.


  • Top entry Ball Valve

The top entry ball valves are the valves that assemble the ball from the top end.  It consists of a single entity. Typically, the top entry ball valves are made of cast metal. Ball valves are commonly used in oil and gas pipelines as well as in oil, refining, petrochemical, chemical etc.


Ball Design

  • Floating Ball Valve

The floating ball is the most common ball design in ball valves . Floating ball valve has the ball inside the valve that is kept in the particular position by compressing two elastomeric supports towards the ball so that the ball can float inside the valve. At the top of the ball, the shaft is connected and allows the switch from open to closed position with a quarter turn movement. When the shaft is moved, a load is applied to the ball which gets pressed against its seats. The ball floats and the seats are stable. This design is highly feasible and it suits bore sizes up to 10 inches.


  • Trunnion Ball Valve

The primary function of a trunnion is to provide a stable axis of rotation for a moving part. In a trunnion ball valve, the ball is backing by an additional support at its bottom which is in shape similar to shaft is called trunnion. This holds the ball in its place and limits the movement of the ball to its axis. The ball can only move if the valve shaft rotates. Trunnion ball valve also feature spring -loaded seats. The inlet pressure activates the spring towards the ball held by the trunnion, which creates a tight sealing.

The trunnion ball valve may have a more complex design than the floating ball valve but it is more reliable and is more durable. Its movable sealing seat is easy to clean.


  • Vented Ball Valve

A vented ball valve, in simple terms, means a ball valve with the upstream portion of the ball drilled. The hole is very small. Their small drilled hole or vent acts as a pressure regulator. It keeps the pressure within the valve equal to that of the system. It is used in preventing various severe consequences.

Vented ball valves are used in cryogenic applications, refrigeration systems, or processes involving substances like liquid nitrogen or liquid oxygen.


Bore Profile

  • Full Bore Ball Valve

A Full-bore ball valves have an oversized ball so that the hole in the ball is the same size as the pipe internal diameter which ensures straight-through flow and positive shut off with minimal pressure drop and very little resistance to the flow of liquid. The full-bore ball valve is generally used on pipelines for conveying viscous and slagging media. Because of its low fluid resistance, it can be said that there is basically no flow resistance, and it is convenient for regular wax scrapers to pass through.


  • Reduced Bore Ball Valve

A reduced bore ball valve is a type of ball valve with ball bore diameter less than the pipe diameter. In a reduced bore ball valve, the area of fluid flow is narrower downstream at the outlet. As such, there are frictional losses introduced in the valve resulting in pressure drop. In reduced bore ball valves, the amount of fluid flow remains constant which makes velocity to increase as the flow area decreases.

Reduced bore ball valves are commonly used, unlike full bore ball valves. Reduced bore ball valves are used where turbulence and fluid flow rate are not major concerns and where buildup of particles is not likely to occur. Reduced bore ball valves cost less relative to full bore counterparts. The lower cost of reduced ball valves is because these valves have smaller housing and ball size which affects the final product cost. Reduced bore ball valves occupy a smaller volume which makes them consume small space during installation. Reduced bore ball valves are 30% lighter in weight relative to the full-bore ball valves. However, reduced bore ball valves are meant for use in fluids that are not very viscous to avoid valve blockage. 


  • Segmented Ball Valve

A segmented ball valve has a V-shaped notch on its ball. A segmented ball valve has good flow rate control which depends on the ball rotation. This valve has good rangeability control, and shutoff capability. The V-notch ball provides positive shearing action and produces an inherent equal percentage flow characteristic. It provides non-clogging, high-capacity flow control.


Other Types of Ball Valves

  • Cavity filled Ball Valve

The cavity filled ball valves are with PTFE or TFM filler for the valve cavity . This eliminates the possibility of entrapped media or particle build-up over time around the ball which can cause contamination or blocking of the fluid flow.

Cavity-filled ball valves are easier to clean and maintain. Cavity-filled ball valves are valuable in industries where sanitation is crucial, such as in food, pharmaceutical, and bioprocessing industries. They are ideal in handling solid-liquid mixtures such as slurries.


  • Multi-Port Ball Valve

A multi-port valve is a type of valve which has normally more than two ports and it can have either 3,4 or 5-way control depending on the application.

A multi-port valve works by changing the direction of flow internally using a pre-designed flow path and can switch between 90 degrees or 180 degrees alone the media to flow via two ports or three ports if necessary.

The main uses and applications of a multi-port valve in industry, can be used to reduce the number of valves in the process line, rather than having 2 x 2 port Valves, it may be possible to install a 3-way valve to carry out the same function.