Inline pressure balance expansion bellows are designed to absorb axial movement while balancing the internal pressure thrust within a piping system. These expansion joints are engineered to absorb movement without transferring pressure thrust to the surrounding anchors or equipment. This capability is particularly beneficial in systems where it is difficult or impractical to install large external anchors to manage the thrust forces created by internal pressure.

The unique design of inline pressure balance bellows makes them suitable for high-pressure applications where the piping system must accommodate thermal expansion and contraction without placing excess stress on supports, anchors, or adjacent equipment. These bellows are widely used in industries such as power generation, oil and gas, chemical processing, and refineries.

How Inline Pressure Balance Bellows Work

The primary function of inline pressure balance expansion bellows is to absorb axial movement while maintaining balance within the system by neutralizing the pressure thrust. The bellows use a combination of main expansion bellows and balancing bellows that work together to counteract the forces generated by internal pressure.

1. Absorption of Axial Movement:
   Inline pressure balance bellows are designed to absorb axial expansion and contraction, which occurs due to temperature changes in the piping system. This is crucial in high-temperature environments where the length of the pipe can change significantly due to thermal expansion. The bellows allow for smooth axial movement, minimizing stress and preventing damage to the pipeline.

2. Pressure Thrust Neutralization:
   One of the key advantages of inline pressure balance bellows is their ability to neutralize the pressure thrust created by internal pressure within the system. In conventional expansion joints, internal pressure creates a force that pushes the bellows apart, causing stress on anchors and adjacent equipment. In contrast, inline pressure balance bellows are equipped with balancing bellows that counteract this force, ensuring that no pressure thrust is transmitted to the supports or anchors.

3. Equal and Opposite Force Design:
   The design of inline pressure balance bellows is based on the principle of equal and opposite forces. The main bellows absorbs the axial movement, while the balancing bellows located in a separate section or chamber of the unit creates an opposing force. This cancels out the internal pressure thrust, ensuring that the system remains stable and the pressure forces are internally balanced. This design eliminates the need for large external anchors that would otherwise be required to absorb these forces.

4. Thermal Expansion Compensation:
   As with other expansion bellows, inline pressure balance bellows help compensate for the thermal expansion and contraction that occurs in piping systems exposed to high temperatures. This is especially important in industries such as power generation, where steam pipes experience large temperature fluctuations, or chemical processing, where pipes carry high-temperature fluids.

Technical Specifications

• Size Range: Inline pressure balance expansion bellows are available in sizes ranging from 100 NB to 4000 NB, making them suitable for both small and large industrial systems.

• Temperature Range: These bellows can handle temperatures of up to 1000°C, making them ideal for use in high-temperature applications.

• Pressure Range: Inline pressure balance bellows are designed to withstand pressures of up to 100 bar, providing durability and stability in high-pressure environments.

Types of Inline Pressure Balance Bellows

1. Axial Inline Pressure Balance Bellows:
   These bellows are specifically designed to absorb axial movement in the piping system. They feature a set of main bellows to absorb axial expansion and a set of balancing bellows to counteract the internal pressure thrust, ensuring the system remains stable without transferring any forces to external anchors.

2. Custom Inline Pressure Balance Bellows:
   Custom designs are available to meet the specific requirements of various industries. These custom bellows can be made with different materials, such as stainless steel or nickel alloys, to suit the media being transported, temperature conditions, and pressure requirements.

Applications of Inline Pressure Balance Bellows

Inline pressure balance bellows are used in a variety of industrial applications where axial movement needs to be absorbed, but pressure thrust must be managed internally. Their unique design makes them essential in systems where the installation of external anchors is difficult or impractical.

1. Power Generation:
   In power plants, particularly in steam lines and boiler systems, inline pressure balance bellows are used to accommodate the expansion and contraction of pipelines caused by thermal changes. The ability to balance internal pressure thrust without large external anchors is critical in these environments, where space and support structures are often limited.

2. Oil and Gas Industry:
   Inline pressure balance bellows are widely used in refineries, offshore platforms, and petrochemical plants where pipelines transport crude oil, natural gas, and other fluids under high pressure and temperature. These bellows ensure that the pressure thrust is balanced within the system, preventing excessive loads on supports and anchors.

3. Chemical Processing Plants:
   In chemical plants, pipelines transport hazardous chemicals and corrosive fluids at high temperatures and pressures. Inline pressure balance bellows absorb the axial movement caused by thermal expansion while neutralizing the pressure thrust, ensuring that the system remains stable and safe for continuous operation.

4. HVAC Systems:
   In large HVAC systems, inline pressure balance bellows are used to manage the thermal expansion of pipes carrying air or gases under pressure. By balancing the internal pressure thrust, these bellows protect the system from stress and ensure efficient operation without the need for large external supports.

5. Water Treatment and Sewage Systems:
   Inline pressure balance bellows are also used in water treatment plants and sewage systems, where large pipelines transport water and waste under varying temperatures and pressures. These bellows absorb axial movement without placing additional stress on anchors or supports, ensuring the longevity and efficiency of the system.

Advantages of Inline Pressure Balance Bellows

• Neutralization of Pressure Thrust: The primary advantage of inline pressure balance bellows is their ability to neutralize the internal pressure thrust, ensuring that no forces are transmitted to external supports or anchors.

• Axial Movement Absorption: These bellows effectively absorb axial movement, allowing pipelines to expand and contract due to temperature changes without causing stress on the system.

• No Need for Large External Anchors: By balancing the pressure thrust internally, inline pressure balance bellows eliminate the need for large external anchors, making them ideal for systems where space is limited or where external supports are difficult to install.

• High Temperature and Pressure Resistance: Inline pressure balance bellows are capable of withstanding temperatures up to 1000°C and pressures up to 100 bar, making them suitable for use in extreme industrial environments.

• Longer System Lifespan: By reducing the stress on pipelines and supports, inline pressure balance bellows help extend the life of the piping system, reducing the need for frequent maintenance or repairs.

Conclusion

Inline pressure balance expansion bellows provide an effective solution for managing axial movement in piping systems while neutralizing the internal pressure thrust. Their unique design, featuring both main and balancing bellows, allows them to absorb axial expansion and contraction without transferring pressure forces to external anchors or supports. This makes them ideal for industries such as power generation, oil and gas, chemical processing, and HVAC systems, where high temperatures, pressures, and space limitations are common. With their ability to handle extreme conditions and extend the lifespan of piping systems, inline pressure balance bellows are a crucial component in ensuring the stability and efficiency of complex industrial networks.