Electric Ball Valve: Complete Guide

What is an electric ball valve?

An electric ball valve is a type of ball valve that is operated using electric actuator. As the name suggest, the actuator used in electric ball valves is electric actuator. This is an actuator which is powered by electrical energy. This type of ball valve employs a hollow ball which when it turns 90^o helps to block or open fluid flow. Electric ball valves are used for on/off fluid flow applications. Electric actuated ball valves initiate the fluid flow when the ball hole becomes parallel to the fluid flow direction. Electric ball valves are known for being reliable and of long service life if used according to the manufacturer’s instructions. Electric actuated ball valve manufacturers design these valves in a way that makes them strong against corrosion, high pressure, and high temperature. 

Figure: Electric ball valve.

Components of electric ball valves 

Valve body

This is the component of the electric ball valve that contains all internal parts of the valve. The valve body is designed to be very strong relative to the intended application.

Bonnet

Bonnet is the component of an electric actuated ball valve placed above the valve body to help in protecting internal components as well as enhance tight seal with the valve body. The bonnet is an electric ball valve is made with the same material as the valve body to ensure compatibility for high strength without breaking either valve body or bonnet and thus guarantee a tight seal. 

Stem 

The stem is the component of the electric ball valve which is connected to the electric actuator at the top and the bottom is connected to the ball. The stem is used to transmit force from the actuator to the ball so that it can turn on or off the electric ball valve. 

Ball 

The ball in the electric ball valve is an internal component designed with a hole at the center where fluid flows through. The ball is connected with the stem so that when the stem rotates it can rotate the ball. 

Seats 

Seats are discs lying between the ball and the valve body. The seats in the electric ball valve provide a seal between the body and the ball and also help to support the ball. 

Packing

Packing is a seal placed around the stem to prevent fluid leakage. 

How does the electric ball valve work? 

An electric ball valve uses a ball with a hole at its center. The position of the hole on the ball determines when the valve closes and when it opens the fluid flow. The electric ball valve has the ball connected to the stem. The stem is connected to the electric actuator. The working of an electric actuated ball valve is as follows: 

1. The electric actuator rotates the stem for 90^o. When the stem turns, it also turns the ball. When the hole on the ball is in the same direction as the fluid flow, the fluid flows through the valve. 
2. To stop fluid flow, the actuator rotates anticlockwise direction for 90^o which simultaneously rotates the stem and thus the ball turns anticlockwise 90^o stopping fluid flow. Electric actuated ball valves are used for on/off fluid flow applications. If the electric actuated ball valve is used for throttling applications under high-pressure applications, the seats easily get damaged. 

Figure: Working of an electric actuated ball valve.

Types of electric ball valves

Two-way electric ball valve 

This is an actuated ball valve that has two ports that is inlet and outlet ports. This electric ball valve is designed such that fluid flows from the inlet port to the outlet port via the ball hole. This type of electric ball valve is used for on/off flow applications. As such, this valve is also known as an electrically actuated shut-off ball valve. 

Three-way electric ball valve

This is an electric actuated ball valve that has three ports. The design of this electric ball valve employs a T or L formation. This design of an electric actuated ball valve enhances various valve circuit functions because it can manipulate flow directions. As such, three-way electric actuated ball valve is used in fluid application such as fluid distribution and fluid diversion as the user needs. In a electric three way ball valve, any of the three ports can be the outlet or the inlet. 

One-piece electric ball valve 

This is an electric actuated ball valve with one piece of the body that contains all the internal parts of the valve. This type of electric ball valve reduces the chances of leakage from the valve. One-piece electric ball valves are cheap relative to other electric ball valves. If the one-piece body is made through welding it renders it impossible to disassemble for cleaning and repair works when it gets damaged. As such, one-piece welded electric ball valves can only be used where particle build-up is not easy to occur and where the major concern is no sanitation. For one-piece electric ball valves connected using screws are easy to clean and repair. However, their disassembling needs special tools. 

Two-piece electric ball valve 

This is an electric actuated ball valve made up of two pieces connected together. One piece of this electric ball valve contains the valve ball and connection to the other side. The second piece of the electric ball valve is used to hold internal parts together and it as well has connection to the other side. The two-piece electric actuated ball valve is the most common type of electric ball valve. The two pieces in electric ball valves can be disassembled when you need to do an inspection, clean, do maintenance, and repair works. The connections which are mostly threads, bolts, and screws are easy to remove to perform such maintenance practices. 

Figure: Two-piece electric ball valve.

Three-piece electric ball valve 

This is an electric actuated ball valve that has housing for internal components of the valve connected and held together by use of bolts and nuts to the other two ends. The other ends are welded or threaded to the main pipe. This type of electric ball valve is used where valves are used frequently such that the valve needs maintenance quite often. Thus three-way electric ball valves are preferred because they can easily be cleaned and serviced. Three-way electric actuated ball valves have their seals and seats easy to replace by removing the valve body without disturbing the other two ends. Three piece ball valves are used in various applications among them food and beverages and pharmaceutical industries where proper hygiene is very important for the safety and quality of the manufactured product. 

Figure: Three-piece electric ball valve.

Top entry electric ball valve 

Top entry electric actuated ball valves are valves designed such that it is easy to access internal parts of the valve by removing the top cover (bonnet). This makes electric top entry ball valves easy for in-line maintenance operations such as disassembly, inspection, cleaning, and repair works without removing the ball from the pipe. 

Trunnion electric ball valve 

This is an electric ball valve in which the ball is supported by an extra shaft at the bottom. This shaft is known as a trunnion. This helps to hold the ball in place and restricts ball movement to its axis. In the electric trunnion mounted ball valve, the seats are loaded with springs. Inlet pressure from the fluid flow activates the springs to the ball held by the trunnion which then creates a tight seal. Trunnion electric ball valves operate efficiently in different pressure ranges and are suitable for use in high-pressure applications. 

Applications of electric ball valve 

• Used in food and beverages processing. 
• Pharmaceutical industries. 
• Water treatment and irrigation systems. 
• Oil and gas industries. 
• Dishwashers and washing machines. 
• These valves are used in heat exchangers. 
• Different manufacturing industries such as chemicals, steel, plastics among others. 

Advantages of electric ball valves 

• They can be automated or semi-automated as per user’s preferences. 
• Easy to clean, dismantle and repair. 
• Small volume and weight relative to other valves like gate valve. 
• Employ a simple design that reduces their cost. 
• Operate quickly. 
• Work in high pressure and high-temperature applications. 
• These valves provide a tight seal between joints. 
• Low-pressure drop and high fluid flow rate. 
• Efficient in fluid flow control as they do not need lubrication and have a tight seal. 
• Affordable relative to other valves of the same job category. 
• Versatile as they can be used for different applications in different industries. 

Disadvantages of electric ball valves 

• Not suitable for throttling applications. 
• Close and open quickly which creates overpressure and hammering problems. 
• High wear and tear when used for the wrong application. 

Troubleshooting electric ball valves 

Leakage at the connection threads/bolts/screws 

• Improper threads. Check the electric ball valve for the proper size of threads, bolts, screws. 
• Improper or insufficient thread sealant. Reinstall thread connection as per the outlined manufacturer’s procedures. 
• Thread joint over-tightened splitting the connector. Replace the end connector and apply the right torque to avoid damage again. 

Leakage at the union nuts 

• The electric ball valve has a misaligned end connector. Align the end connectors properly. 
• Damaged or displaced O-rings. Debris in the O-ring groove. Inspect the O-ring for chemical or physical damage. Replace damaged O-ring. Clean any particles in the groove. 
• Loose union nuts. Tighten union nuts. 

Leakage at the electric ball valve stem 

• Stem O-ring damaged. Inspect the O-ring for physical or chemical damage and check O-ring compatibility with the media. Replace the O-ring. 

Internal leakage 

• Ball obstruction. Check for solid particles blocking the ball and clean. 
• Broken stem. Remove electric ball valve end connectors and inspect the stem. Replace as necessary. 

Electric actuator not working 

• The capacitor is not connected properly or is loose. Check the manufacturer’s wiring diagram and correct the connection accordingly. 
• Terminal block wires are loose or disconnected. Check the wires and re-connect accordingly. 
• Switch, wires, or other leads are disconnected or loose. Inspect these components and reconnect accordingly. 
• The motor is damaged or not operable. Check motor voltage is as recommended by the manufacturer. Replace the motor if necessary. 

The electric actuator rotates in one direction only 

• Terminal block wires lose or disconnected. Check the wires and correct them accordingly. 
• The Control board component has failed. Inspect this component and do re-wiring or replace the board. 

Summary 

Electric ball valves are ball valves that use an electric actuator. Electric ball valves work by using a hollow ball which is turned by the electric actuator at 90^o to open or close the fluid flow. Electric ball valves are best suited for on/off applications and they can be fully automated or semi-automated. The flow in electric ball valves starts when the ball is rotated such that the ball hole becomes parallel to the direction of fluid flow. Electric ball valves are strong for high-pressure and high-temperature applications.

Electric ball valves are used in various applications such as food and beverages processing, oil and gas, pharmaceuticals, water treatment and irrigation systems, dish and washing applications among others. These valves are known for being efficient, durable, versatile, and easy to use and repair, strong, and have a perfect seal. There are various types of electric ball valves such as one-piece electric ball valve, two-piece electric ball valve, three piece electric ball valve, two way electric ball valve, three-way electric ball valve, trunnion electric ball valve among others.