The working principle of the bidirectional directly buried compensator is based on its unique design, which enables it to absorb axial displacement in both directions in the pipeline system. Such compensators are commonly used in directly buried pipeline systems, such as pipeline networks that supply heat, gas, or liquid, to cope with thermal expansion and contraction of pipelines due to temperature changes. Here's how the two-way direct buried compensator works:
Basic structure
Bidirectional directly buried compensators are mainly composed of bellows (or corrugated joints), guide structures, sealing devices and possible additional components (such as limiting devices, pre-tensioning devices, etc.).
Working Principle
Bellows deformation：
The bellows is the core part of the bi-directional directly buried compensator and is formed by a series of alternating bumps and depressions, such a structure that enables the bellows to extend or compress in the axial direction.
When the pipe expands due to increased temperature, the bellows will compress under the action of internal pressure; Conversely, when the pipe shrinks due to cooling, the bellows will stretch.
Two-way compensation capability：
Unlike the unidirectional compensator, the bellows of the bidirectional directly buried compensator are designed to compensate in both directions.
This means that regardless of which direction the pipe is moving (elongated or shortened), the bellows will be able to compress or extend accordingly, thus absorbing the displacement of the pipe.
Guide and Limit：
To ensure that the bellows move only axially, the compensator is usually equipped with guide structures, such as guide rods or guide rings, which limit the lateral displacement of the bellows.
The limiting device prevents the bellows from excessively extending or compressing, protecting it from being damaged.
Sealing and protection：
Sealing devices (such as packing seals, mechanical seals, or rubber seals) are used to ensure a seal between the bellows and the pipe to prevent media leakage.
An external shield or enclosure can protect the bellows from external environmental factors such as soil pressure, corrosion.
Special design
In some designs, a bidirectional directly buried compensator may contain additional mechanisms such as:
Pre-stretched or pre-compressed: At the time of installation, the compensator may need to be pre-stretched or compressed to reserve sufficient compensation space in the ductwork.
Double bellows structure: Some designs may employ a double bellows structure, where one bellows is responsible for compensation and the other provides additional sealing or protection.
These designs and working principles of the two-way direct buried compensator make it an important component in the direct buried pipeline system, which can effectively reduce the pipeline stress and protect the pipeline from damage caused by thermal expansion and contraction, thus improving the overall stability and service life of the pipeline system.