One-Piece vs. Two-Piece Ball Valve: Which One to Choose? | Dombor

09 Jun.,2025

 

One-Piece vs. Two-Piece Ball Valve: Which One to Choose? | Dombor

Every ball valve, whether manual or operated, flanged or NPT, brass or stainless steel, serves a different purpose for an industrial piping system. That’s why it is vital to understand their operation and features to select a suitable one from the best valve manufacturer in China.

Afbv Valve are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

A one-piece ball valve features a solid cast body to reduce the risk of leakage. It is inexpensive, and it is ‌impossible to repair it. Similarly, fixing a two-piece ball valve is impossible unless it is removed from service. Such a valve comprises two pieces where one piece has one end connection and the body. The other piece fits into the first one to hold the trim and includes the second-end connection.

Although the differences between these two valves are tricky, their understanding is essential for various processes. So, let’s learn everything about one-piece vs. two-piece ball valves!

Everything to Learn About One-Piece Ball Valve:

A single or a one-piece ball valve features only one body part. In this device, the trim attaches to the seals through end connections made of the same material as the body. Since its port size is not the same as its line, it results in a small bore design. A device bought from an industrial ball valve company comprises a ball, a PTFE ring, and a lock nut.

Users rarely or never experience leakage problems with this type of construction. However, the main downside to this type of device is it is irreparable, i.e., it cannot be replaced. It features a reduced diameter, and its flow diameter is smaller than the thread diameter.

Advantages of Using One-Piece Ball Valve:

  • It provides little fluid resistance and zero friction on the switch.
  • Its resistance coefficient is similar to that of the same length of pipe.
  • It is lightweight and takes up very little space in a piping system.
  • Its sealing surface material is used with good sealing performance and a vacuum system.
  • It is easy to operate and quick to open and close due to 90 degrees rotation.
  • Its maintenance is convenient as its structure is simple, the sealing ring is movable, and it is convenient to replace and dismantle.
  • It is more affordable than its competitors due to its simple design.

Since it is a relatively new ball valve type, it offers some unique advantages, reducing the size of the actuator. Its working principle is to make the valve unblocked or blocked by rotating it.

In high-demand industries, a one-piece ball valve is rarely employed because they are difficult to repair and replace. However, a one-piece ball valve can be utilized in applications where a reduced flow is not a concern. It works effectively in such applications. Some common uses of this device are in food service machinery, liquid filling equipment, and motor fluid filing equipment.

Everything to Learn About Two-Piece Ball Valve:

A two-piece ball valve contains two independent components connecting them through a bolt, thread, or flange assembly. These pieces have body and end connections. However, since two separate sections are combined in this valve body, there is a high chance of leakage. It is used to cut off, distribute, and alter the flow direction of the medium in the pipeline.

As a result, a two-piece ball valve is unsuitable for high-pressure applications. Unlike a one-piece valve, it is possible to disassemble it for internal component repair because of the connection. Its sealing effect is better than a one-piece ball valve and is further divided into a top entry floating ball valve, an elastic, and fixed one.

Advantages of Using Two-Piece Ball Valve:

  • It offers minimal fluid resistance whose coefficient is equal to the same length of a pipe.
  • It is lightweight, occupies less space, and its design provides good sealing performance.
  • Its structure is convenient to repair and maintain due to its simple design and movable ring.
  • Since the valve seat and sealing are isolated from the medium, there is no corrosion on the sealing surface.
  • Its medium does not erode the piece quickly because its sealing cover and seat are isolated.
  • It requires only a 90 degrees turn to open or close, thus making it convenient for remote control.

A two-piece ball valve is commonly used in various applications with any media because of the ease of maintenance in a wide range of industries. A few industries employing a two-piece ball valve in their applications include food, manufacturing, and automotive. Its working principle is to block the valve or unblock it by rotating it.

Difference Between One-Piece and Two-Piece Ball Valve:

Here is a quick table to help people understand everything they need to know about one-piece vs. two-piece ball valves:

In industrial piping systems, a ball valve functions as a shut-off device to regulate the flow of media, especially liquids and gases, passing through it. It controls the flow by rotating the ball with a bore located inside it. Industrial valve manufacturers offer their devices in several industries, including chemical storage, oil and gas, residential applications, and manufacturing.

Since it is available in many types, such as one piece, two pieces, and three pieces, choosing the one with a body suitable for a particular application often becomes challenging. While a one-piece ball valve has only one body portion, a two-piece valve has two body components threaded together.

For more 1 Piece Ball Valveinformation, please contact us. We will provide professional answers.

Parting Words

A one-piece ball valve is typically considered a thrown-away because it is difficult to repair it for maintenance. But it is still an economical option than its counterparts, such as a two-piece valve that feature a main body and a single-end connection. One can quickly repair it, but it is often difficult due to galling in the threads when the end plug removes from the valve body.

A Guide to One-, Two-, and Three-Piece Ball Valves | Tameson.com

A Guide to One-, Two-, and Three-Piece Ball Valves

Figure 1: One-piece ball valve

A ball valve is a shut-off valve in piping systems, controlling the flow of liquids or gasses. Understanding the differences between 1, 2, and 3-piece ball valves is essential for selecting the right valve for any application. This article examines the design, performance, and specific applications of these ball valve configurations. This article compares 1, 2, and 3-piece ball valves in detail. Read our ball valve overview article for more details on the design and working of ball valves.

Table of contents

  • 1, 2 & 3-piece ball valve
  • One-piece ball valves
  • Two-piece ball valves
  • Three-piece ball valves
  • 1, 2 & 3-piece ball valves comparison
  • FAQs

1, 2 & 3-piece ball valve

In short, the main difference between 1, 2, and 3-piece ball valves is their body design. A one-piece ball valve has only one body portion. Two-piece ball valves have two body components threaded together or bolted together. Three-piece valves, on the other hand, have three independent components.

One-piece ball valves

Construction

Building a single-piece ball valve is simple as there is only one body part. The valve trim is attached to the seals through end connections made of the same material as the body. Also, the valve's port size will not be the same as the line size, resulting in a reduced bore design. There is very little or rather no leakage with this type of construction. A one-piece ball valve is irreparable, and it can only be replaced. Figure 1 shows a one-piece ball valve.

Advantages

  1. Due to its simplicity, a one-piece ball valve is relatively cheaper compared to other ball valves.
  2. It offers little fluid resistance and no friction on the switch.
  3. The one-piece valve is also light and occupies less space.
  4. A one-piece ball valve can be easily turned on and off.
  5. The medium does not quickly erode the piece since the sealing surfaces, and the valve seat is isolated from the medium.

Applications

One-piece ball valves do not have uses in high-demand industries since they are difficult to repair or replace. In applications where a reduced flow is not a concern, one-piece valves can be employed. Foodservice machinery, liquid filling equipment, and motor fluid filling equipment use one-piece ball valves.

Two-piece ball valves

Construction

Two-piece valves have two independent components connecting them, either threaded or a bolt and flange assembly. The pieces have body and end connections. As two separate sections are connected, there is the possibility of leaking. As a result, the two-piece ball valve is unsuitable for high-pressure applications. Because of the connection, the valve can be disassembled for internal component repair.

Advantages

  1. There is no corrosion on the sealing surfaces since the valve seat, and the sealing is isolated from the medium.
  2. The structure of the ball valves is also convenient for repair and maintenance.
  3. It is easy to open or close the ball valve. You only require a 90⁰ rotation on the handwheel.
  4. The ball valves are compact hence providing good sealing performance.
  5. The ball size occupies less space, and it is lightweight.
  6. Fluid resistance is minimal.

Applications

A two-piece ball valve's structure allows it to be used in various applications. The valve can be used with any media because of the ease of maintenance. Food, manufacturing, and automotive industries are just a few of the industries that use two-piece ball valves.

Figure 2: 2-piece ball valve

Three-piece ball valves

Construction

A three-piece ball valve has one main valve body and two pipe connectors. The pipe connectors are welded or threaded to the pipes. Because of the three-piece structure, the valve body and trims can be removed without interfering with the pipe connections. After installing a 3-piece ball valve, the worn-out components like the ball, seat, or stem can be replaced independently and quickly. It is also more expensive than a two-piece ball valve due to its intricate structure. But, the valve can remain in service for its intended lifespan with low long-term maintenance cost.

Advantages

  1. A three-piece ball saves cost in the long run as it can be cleaned and maintained easily.
  2. The main body of the valve can be removed without interfering with the connections, avoiding a line shutdown.
  3. The valve provides for full port and bidirectional shut-off.
  4. The valve seals can be easily changed by just unbolting the caps.
  5. The connection in a three-piece ball valve is complete compared to a one or two-piece ball valve.
  6. These valves can be used in a high-pressure vacuum.

Applications

The structure of a three-piece ball valve makes it suitable for high-pressure applications where the components experience a lot of wear and tear. The valve is ideal for high-cycle industries since the parts can be replaced and serviced without replacing the entire valve. Primarily, manufacturing industries mainly rely on three-piece ball valves to control liquid flow.

Figure 3: 3-piece ball valve made of stainless steel

The company is the world’s best Stainless Steel Gate Valve supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

1, 2 & 3-piece ball valves comparison

Cost

  • Acquiring a one-piece ball valve is the cheaper option.
  • Two-piece ball valves are affordable to purchase and replace compared to three-piece ball valves.
  • Three-piece ball valves have a high one-time cost, but in the long run, they are cost-effective.

Port availability

  • One-piece ball valve does not have the same port size as the line.
  • Two-piece and three-piece ball valves are available in full port configurations.

Repair and service

  • You cannot repair one-piece ball valves.
  • Two-piece ball valves allow for limited repair.
  • It is expensive to acquire three-piece ball valves

Applications

  • One- and two-piece ball valves have typical food, liquid filling, and automotive industry applications.
  • Three-piece ball valves have high-pressure applications in manufacturing industries.