A ball valve is a subcategory of a shut-off valve that controls the flow of a liquid or a gas. As the name suggests, it is controlled by a rotary ball that has a bore. When the ball is rotated 90 degrees about its axis, the fluid either freely flows through the valve or is obstructed, unlike a control valve that regulates the flow of fluids.
The number of ball valve options is seemingly infinite. To decide which ball valve suits your specific requirement, several aspects have to be compared, like seat material, end connections, port ball, number of pieces, and the type of packing.
As for the number of pieces, ball valves are available in one, two, or three pieces. A one piece ball valve is inexpensive and easily replaceable. Hence, it is not repaired. It is used for functions with low loads and pressures. The main confusion occurs between the use and advantages of a 2 piece ball valve vs. 3 piece ball valve. The differences between the two valve types are listed out below.
2 Piece Ball Valves
A 2 piece ball valve consists of two separate pieces that are either connected via a bolt and flange assembly or threaded assembly. 2 piece ball valves are the most widely used ball valves and are suitable for any application where the flow of liquids and gases needs to be controlled.
These are also referred to as 2 way ball valves since it allows a liquid or gas to flow in any direction between the inlet and outlet. One piece of this valve comprises an end connection and the body.
Its second piece fits into the former, holding the trim in place and providing the second end connection. This ball valve type can be utilized for bidirectional flow shutoff or full port service. The flow rate in 2 piece ball valves can be controlled by partially opening or closing the valve.
When these valves have a threaded assembly, they can be installed easily with no tools required. Once installed, these valves need to be removed from the overall assembly in order to be repaired or cleaned.
Advantages Of 2 Piece Ball Valves
The best way to understand the differences between a 3 piece vs 2 piece ball valve, is to understand the advantages of both. Listed below are the advantages of 2 piece ball valves.
- Easy To Install: 2 piece ball valves are lightweight, small, and have a simple structure. Its small diameter ensures that it is easy to install, and the small actuator size facilitates frictionless movement.
- Minimal Fluid Resistance: In this type of ball valve, the resistance coefficient is equal to that of a pipe of the same length, which means that fluids can flow through seamlessly.
- Good Sealing Performance: These ball valves close tightly and have a strong seal, which gives them high sealing performance, hence, reducing the possibility of leakage. Materials like metal, EPR, EPDM, and PTFE are used on the sealing surface.
- Operational Convenience: 2 piece ball valves can be swiftly opened and closed as desired when rotated to a complete right angle. It can also be remotely operated if required.
- Easy Maintenance: The valve structure is simple, which makes it easy to maintain. When it is fully open or closed, the seat sealing surface is isolated from the fluid, which minimizes the risk of erosion of the sealant.
Applications
2 piece ball valves can be used for a variety of applications since their diameter can vary from a few millimetres to a few meters. Its simple structure, high sealing performance, and operational convenience make it ideal to be used under high pressure or vacuum conditions. 2 piece ball valves are typically used in foodservice equipment, automotive fluid filling devices, and liquid filling equipment.
3 Piece Ball Valves
A 3 piece ball valve comprises three pieces, specifically, a pair of connecting ends and the main body. The end cap can be connected to the pipeline via a flanged, welded, clamped, or threaded assembly.
One of the most significant advantages of 3 piece ball valves is that they are easy to disassemble. Its central body can be removed for maintenance and cleaning without disrupting the entire pipeline’s functioning.
Once cleaned and serviced, the central body can be reattached to the end caps without any hassle, hence, reducing maintenance costs. If the price of a 3 piece ball valve vs 2 piece ball valve is compared, the former is more expensive but can be cheaper in the long run since maintenance costs are reduced.
Advantages Of 3 Piece Ball Valves
- Sound design: Since this type of valve has three pieces and it has a simple, lightweight design, it can easily be assembled or installed and disassembled with no hassle.
- Fluid Resistance Is Low: The resistance coefficient is equal to the pipe diameter of the same length for 3 piece ball valves. This ensures that fluids can flow easily, and it reduces the chance of blockages being formed. In addition, most of these valves are full bore designs, which allows more fluids to be transported.
- High Sealing Performance: Changing seals and seats is more cost-effective in this type of ball valve. Since they close tightly when welded, it forms a strong seal that prevents leaks.
- Operational Ease: A 3 piece ball valve is suited for frequent and rapid opening and closing without friction. To fully open or close it, the lever or driving device needs to be turned to 90 degrees, which also facilitates remote operation.
- Easy Maintenance: 3 piece valves facilitate easy maintenance since the central body can be removed for servicing without removing the pipe connectors or end caps. This way, the line can continue to function without shutting down completely for maintenance. In addition, the body can be moved and welded with the trim out of the way, keeping the internal structure sound and damage-free.
Applications
3 piece ball valves are preferred for processes that have a heavy reliance and demand on valves. Since these processes require the sealants and seats to be routinely replaced, a 3 piece valve offers flexibility in terms of disassembly, servicing, and reassembly, without stopping the entire pipeline.
In addition, valves offered by leading valve vendors have the added advantage of easy elastomer change. Due to this aspect, the valves are suitable for different process conditions, flows, pressures, and even temperatures, making them ideal for high-cycle or extreme operations, as seen in the manufacturing industry.
Comparison Between 2 Piece Vs 3 Piece Ball Valve
From a larger perspective, both the 2 piece and 3 piece ball valves are used to completely start or stop the flow of fluids. The main point of comparison in the debate of a 3 piece vs 2 piece ball valve for a specific function lies in their design.
While a 2 piece valve is more economical as compared to a 3 piece valve, the latter can prove to be more cost-effective in the long run since it is easier to maintain. A 3 piece valve’s main design advantage is that it can be easily disassembled, and its seats and seals can be changed, while its end caps can continue functioning in the line.
Conclusion
Ball valves are among the most widely used valves and are used to completely start, stop or regulate the flow of fluids in a system. They are utilized for several commercial, industrial, and institutional purposes.
The main difference between 2 piece and 3 piece ball valves is that the latter is costlier but can be disassembled, serviced, and reassembled. Ultimately, the choice between the two boils down to budget and maintenance needs. Contact a premier valve manufacturer today to get high-quality, custom valves for specific industries.
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