What is a forged ball valve?
A forged ball valve is a valve that operates by using a ball-shaped component to open and close fluid flow. The valve is made through the forging method. Forging method involves shaping metallic materials and alloys in their solid state. Industrial-size tools and heat provide compressive forces that bend the alloys and metals. Dies are also used to shape and cut the materials to the forged ball valve. Depending on the material used to make the valve, forging can be performed in various temperatures. Manufacturing through the forging method has certain advantages, such as saving on materials. Also, since these valves are made through forging, little effort is needed to reshape the material into the proper shape and size, reducing the valve’s overall cost. Most valve users prefer forged ball valves because they are strong, making them ideal for use in high-pressure and high-temperature applications. Also, due to the forging manufacturing method, the material’s grain structure gets more refined, leading to increased overall strength and impact resistance.
Figure: Forged ball valve
Components of a forged ball valve
Hand lever/handwheel
The handwheel or hand lever on a forged ball valve is where the valve operator applies force to turn the valve to either close or open fluid flow.
Stem
The stem of a forged ball valve connects the ball and the handwheel. It ensures that force is transmitted from the hand lever to the ball when the operator needs to operate the valve.
Ball
This is a ball-shaped component with a through hole. The ball opens fluid flow when the hole aligns itself with the pipe conveying the fluid and closes when it is aligned at an angle of 90o degrees to the same pipe. The work of the ball is to close or open the valve as necessary.
Seat
The seat is a component meant to seal the inside of the valve and uniformly distribute ball seating stress. It also prevents fluid leakage between the ball and the valve body when the valve is closed. Forged ball valve manufacturers make the seats from metallic or soft materials like rubber and plastic. The seat material choice depends on the application area and the fluid’s expected temperatures. For hot liquids, metallic seats are used, while for temperatures below 65oC, soft materials are used.
Valve body
The valve body, also known as valve housing, covers all internal parts of the pump, such as the ball, seats, seals, and rings. The body provides the valve’s inlet and exit ports for the fluid flow. It also helps to prevent contaminants and solids from entering the pump.
Bonnet
The bonnet is mounted on the valve body, and the two are connected using bolts and nuts. The work of the bonnet is to cover the valve stem and packing. It also enhances the safety of the stem and packing.
Packing
Packing is a seal that prevents fluid leakage around the stem. It also prevents the entrance of dirt and solids into the pump via the stem.
Figure: Components of a forged ball valve.
How does a forged ball valve work?
A forged ball valve closes or opens liquid flow depending on the alignment of the ball center hole to the valve entry port. The ball gets the power to open/close from the handwheel or hand lever through the stem. The valve opens when the handwheel is rotated in the clockwise direction until it makes an angle of 90o degrees. Turning the handwheel forces the stem to rotate. Since the stem and ball are connected, the ball also makes the same clockwise rotation. Due to the ball rotating for a quarter turn, it makes the hole at its center aligned to the valve entrance and the pipe connected to the valve. As such, the valve is left open, allowing liquid to flow through the valve.
The valve closes when the handwheel is rotated in the anticlockwise direction for another 90o degrees. As such, the ball’s central hole becomes perpendicular to the pipe connected to the valve. This arrangement closes the fluid flow path rendering the valve closed. Due to the valve seat, the fluid finds it hard to leak or flow through the valve. The valve can also be used for throttling in which the hand lever is slightly turned. This allows some amount of fluid flow. However, using a forged ball valve for throttling flow under high-pressure conditions causes valve seats to wear rapidly.
Figure: Working of a forged ball valve.
Types of forged ball valves
Three-way forged ball valves
This valve type has three ports, unlike the most common one with two ports (inlet and exit ports). Forged ball valve manufacturers design this valve for mixing and diverting fluid flow in different industrial applications. This valve is advantageous because it does the work that two or more valves can do. The valve operates by turning the ball via the handwheel. The ball rotation aligns its center cut-out channels to the valve inlet and outlet ports. Two versions of the valve are the T version and the L version. The valve with L-shaped cut-out bore allows fluid flow at a 90o degrees from one port to another. The valve has two inlets and one outlet. For the L-shaped valve, fluid can flow from two different inlets to the exit at an angle of 90o degrees.
Figure: T and L forged ball valve.
The T-patterned valve is also known as a mixer-forged ball valve. It is also used to direct fluid flow from right, left, or straight through. Since the valve can combine two fluid streams into one exit stream, this valve is good in applications that need fluid mixing, such as chemical and pharmaceuticals.
Figure: Three-way forged ball valve
Side entry forged ball valve.
A side entry forged ball valve is a valve in which the ball is assembled from its sides. The assembly connects two or three pieces of the valve body. Bolts or studs assemble each body part to join them into two pieces. The assembly is done after the forging each piece of the valve body. Side entry valve types have the advantage of reduced defects common when the valve is made through the casting method. The valve also has the advantage of being easy to assemble and the trim parts being easy to align. These valves are widespread in the market and industries due to their ease of assembly, repair, and cleaning.
Figure: Side entry forged ball valve.
Top entry forged ball valve.
Top entry forged ball valve is one in which the ball is assembled from the top side. This valve is similar to the globe valve but it uses a ball to control fluid flow. The valve is made up of one single body. Forged ball valve manufacturers recommend this valve for use where there is minimum disassembly for maintenance of internal parts. This valve is solid and suitable for heavy-duty applications involving high flow rates and pressure. The construction of this valve allows minimum thread connection, which reduces the possibility of fluid leakage.
Figure: Forged top entry ball valve.
Single-body forged ball valve.
This is a forged ball valve in which the body is made up of one single piece. This type of valve is very reliable since it hardly has any fluid leakage common in other valves whose body is joined using bolts. The valve also has the advantage of being small in size and low cost. However, this valve cannot open its body for repair, maintenance, or cleaning. Once the valve becomes defective, it is no longer helpful. The single-body forged ball valve is best for small flow rate and pressure applications that involve clean fluid free.
Figure: Single body forged ball valve.
Two-piece body forged ball valve.
This is the forged ball valve that has two pieces of the valve body. One of the pieces contains the end joint and the body, while the second piece is attached to the first piece to fix the valve trim in a proper position. One main advantage of using this valve is that it is easy to assemble and disassemble for repair, maintenance, and cleaning. However, it has to be removed entirely from the piping system for the two pieces to be separated. Comparing this valve to the single body type, it is far better since it can accommodate higher pressure and flow rate and it is repairable.
Figure: Two-piece forged ball valve.
Applications of forged ball valves
- Forged ball valves are used in power plants that control water flow at high pressure and temperatures.
- They are used in desalination and water treatment plants.
- These valves are used to manage water flow in the irrigation system.
- Forged ball valves are used in chemical manufacturing plants to control the flow of reactants.
- They are used in pharmaceutical industries.
- These valves are used in food and beverage processing plants.
- They are used in the transportation of municipal and domestic water.
- Forged ball valves are used to control the flow of oil and gas.
Advantages of forged ball valves
- These valves are robust for high pressure and high temperature.
- Depending on the seat material, they can be used for both low and high temperatures.
- Forged ball valves are versatile in size, making them suitable for small to high-pressure applications.
- They are highly durable if used according to the forged ball valve manufacturer’s instructions.
- These valves are of simple and compact design, making them easy to repair, clean, and maintain.
- They open and close quickly, saving time.
- They provide tight seals free from fluid leakage.
- Forged ball valves are easy to operate.
- They can be used in wide range of industrial applications.
Disadvantages of forged ball valves
- The valve seat and ball wear out rapidly when used to control fluids with slurries.
- The valve close and opens quickly, leading to overpressure and hammering failure.
- They are not suitable for throttling applications.
Troubleshooting forged ball valves
The fluid does not flow through the valve
- Foreign materials in the valve. Disassemble the valve according to the forged ball valve manufacturer’s instructions and clean off solids blocking the valve.
- The valve is closed. Turn the valve for a quarter turn to open the fluid flow.
- Pipe blockage. Check the pipe and remove any materials that might be blocking fluid flow.
Leakage from through the seat
- The seat is damaged. Replace the valve seat.
- Foreign materials clogged the seat. Remove the foreign materials.
- Excess fluid pressure. Use the valve at the pressure recommended by the forged ball valve manufacturer.
Leakage through the body gasket
- The bolts connecting the pipe and the valve are loose. Tighten the bolts and nuts.
- The fluid flow is at high pressure. Ensure the valve is used at the pressure recommended by the forged ball valve manufacturer.
- The body gasket is damaged. Replace the gasket.
The valve is hard to operate
- Foreign materials stuck on the stem. Open the valve bonnet and clean off foreign materials.
- Defective seat. Replace the valve seat.
Summary
Forged ball valves are ball valves made through the forging method. This method involves shaping the valve from metallic materials by heating them to a specific temperature. The method results in high-strength valves suitable for high pressure and high temperature. The valve operates by rotating the handwheel for a quarter turn. Rotating the handwheel in the clockwise direction leads to the valve opening and thus allowing fluid flow. Rotation of the handwheel in the anticlockwise direction closes fluid flow.
Forged ball valve manufacturers have varieties of this valve that include single body valves; two-piece forged ball valves, top entry forged ball valves, side entry forged ball valves, and three-way forged ball valves, among others. Applications of this valve include municipal water supply, chemical processing, foods and beverages, irrigation, pharmaceuticals, and power plants, among others. The advantages of using this valve are quick to operate, high strength, versatile in size, durable, and is ideal for various industrial applications.