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Metal Compensator for Gas Pipeline

Jul. 09, 2021

Pipe Compensator

What is a compensator?

Compensator is also known as expansion joint, or bellows expansion joint. The utility model is composed of a bellows (an elastic element) constituting the main body of the bellows and accessories such as an end pipe, a bracket, a flange, a conduit, etc. The utility model belongs to a compensation element. The effective expansion deformation of bellows is used to absorb the size changes of pipelines, conduits and containers caused by thermal expansion and cold contraction, or to compensate the axial, transverse and angular displacements of pipelines, conduits and containers. It can also be used for noise reduction and vibration reduction. It is widely used in modern industry. In heating, in order to prevent pipeline deformation or damage caused by thermal elongation or thermal stress during heating, compensators need to be installed on the pipeline to compensate the thermal elongation of the pipeline, thereby reducing the stress of the pipe wall and the force acting on the valve or support structure.

compensator expansion joint

Types of Compensators

(1) Corrugated compensator

1. The meaning of the corrugated compensator:

The corrugated compensator is a compensating device that utilizes the effective telescopic deformation of the elastic member of the bellows to absorb the dimensional change caused by the expansion, contraction or the like of the pipeline, the duct or the container, and belongs to a compensating element.

Corrugated compensator

2. Advantages of the corrugated compensator:

The utility model has the advantages of compact structure, less space occupation and direct burying; the disadvantage is that the manufacturing is difficult, the pressure resistance is low, and the compensation ability is small. The compensation capacity is related to the outer dimensions, wall thickness and diameter of the corrugated tube: the higher the pressure, the thicker the wall, the smaller the diameter, the greater the rigidity, and the smaller the compensation capacity. Waveform compensator is generally used for applications where the nominal pressure is ≤1.0MPa and the nominal diameter is ≥150mm. It can also be used for large diameter pipes with normal pressure and low pressure. It can be used in boiler flue gas ducts up to DN4000mm.

3. Application conditions of corrugated compensator:

The corrugated compensator cannot bear the weight and should be hoisted separately. Unless the corrugated compensator is used for reinforcement, the corrugated compensator should not be hoisted together with the pipe after welding. In the installation, the degree of the corrugated compensator should be correctly designed according to the data recommended by the manufacturer. Under any circumstances, the bellows cannot be stretched or compressed or twisted to compensate for the installation deviation, so as not to affect the normal function of the corrugated compensator, reduce the service life and increase The piping, equipment, and support members are loaded. There should be enough space around the expansion joint to ensure that the expansion joint can move freely within the design range.

(2) Rotary compensator

1. The advantages of the rotary compensator

(1) High product safety performance: The product structure is reasonable, and the rotary compensator adopts a double seal form, one end is end seal and one side is ring seal;

(2) Convenient design: When designing the heating network, the conditions for compensation of the bellows compensator are harsh. The five golden principles must be followed. The sleeve compensator should be “strictly found” and consider the bellows compensator and sleeve. The stress of the compensator, the blind plate force, and the like. The types of rotary compensators are various, and the compensation problem of the pipeline can be solved by selecting the appropriate type of rotary compensator according to the direction of the pipeline;

(3) Long product life: the life of the product can reach more than 20 years;

(4) Large compensation amount: the compensation amount can reach 1800 mm (other compensators, such as the compensation amount of the bellows compensator, the maximum compensation amount is 300-400 mm). For pipelines above DN 200, the unilateral compensation amount can be reached. 130~200 m, for pipelines with ≤ DN 200, the unilateral compensation amount can reach 100-130 m, which can be used for long-distance transmission steam pipeline compensation;

(5) High economical operation of the pipeline: using the rotary compensator compensation, because the compensator compensates for the distance increase, the elbow is reduced compared with the natural compensation and the sleeve compensation, thereby reducing the pressure drop and reducing the tube loss of the heating network as a long distance conveying. One of the main compensation methods for the heat network;

(6) Installation method and type diversification: According to the direction of the pipeline, combined with the topography of the site, the type of compensation of the rotary compensator is selected to solve the compensation problem of the steam pipeline. The installation is convenient, no need for cold drawing, pre-tightening and other construction processes. Welding can be;

(7) Investment province: Due to the long compensation distance of the rotary compensator, the number of compensators used is reduced, and the thrust of the fixed pier for civil construction is small, the number of fixed piers is relatively small, and the scale of the fixed pier is relatively small, which greatly saves the civil works. Compared with other compensators, the total investment of the project should be saved by 20% to 40%, and the economic benefits are considerable.

2. Application conditions of the rotary compensator:

The rotary compensator is generally installed on the pipeline in groups of 200 to 500 m (determined according to natural terrain), and there are more than 10 installation forms, which can be determined according to the direction of the pipeline. After adopting this type of compensator, the distance between the fixed brackets is increased, and the guide brackets should be appropriately added to avoid the deflection of the pipe sections; in order to reduce the frictional resistance of the pipe sections, a rolling bearing should be installed on the sliding brackets.

(3) Square compensator

Square compensator

1. The meaning of the square compensator

The square compensator is also called a square expansion force or a expansion force bend, and the elastic deformation bent by the tube absorbs the thermal expansion of the pipe. To make a square compensator, a seamless quality steel pipe must be used. The whole compensator is preferably made of a single pipe.

2. The advantages of the square compensator:

(1) It is convenient to manufacture and install. Compared with the sleeve compensator and the corrugated compensator, the axial thrust acting on the fixed bracket is small, and the thermal compensation amount is large, which is suitable for various pressure and temperature conditions;

(2) High safety, no maintenance in normal operation, no need to set up inspection wells.

3. Application conditions of square compensator:

When installing the square compensator, in order to reduce the deformation elastic force and improve the compensating ability of the compensator, the outer arm must be pre-pulled for a certain length and then installed on the pipeline.

Material classification of Compensator

METAL Compensator

The metal corrugated compensator is made of austenitic stainless steel or according to the user’s requirements. It has excellent softness, corrosion resistance and high temperature resistance (-235°C to +450°C), high pressure resistance (up to 32 MPa), can be connected in any direction in the pipeline to compensate and absorb vibration, reduce noise, change the direction of media transport, eliminate pipes or pipes and equipment The mechanical flange displacement, etc., double flange metal corrugated hose is especially suitable for flexible joints of various pumps and valves with displacement and vibration.

METAL Compensator


The elastic elements which constitute the main body of the work are non-metallic materials. Usually, the fabric is made of rubber material. In addition to the high temperature (above 400), the material can not satisfy the operating conditions. All other working conditions can replace fiber fabrics.

Structure and properties of non-metallic fabric compensator

The product mainly uses the unique properties of rubber. Such as high elasticity and high Air tightness Resistance to dielectric and weatherability and radiation resistance. The polyester cord with high strength, heat stability and stability is diagonally checked and checked by high pressure and high temperature molding. The internal density is high and can withstand higher pressure. elastic deformation Excellent results. Product structure design The section has high arc length and long curve, and has a large multidirectional function. It is especially suitable for complex geological conditions and settlement amplitude. Big sum The location of pipeline damage caused by frequent cold and heat changes in pipeline operation. The physical displacement of pump, valve and pipeline displacement is effectively eliminated by the elastic sliding transfer of rubber and the heat dissipation function of deformation mechanical force. Because rubber is a poor conductive material, it is also an ideal environmental protection product for reducing vibration and noise transmission. The product is designed with smooth inner wall. After actual testing, it has no effect on the flow rate and flow rate of the medium, and it will never rust. Basically, it can avoid maintenance during effective campaign period.


piping movements type of compensator


These are used to compensate axial movements. By means of a suitable design, they can also absorb angular and lateral movement.


They are suitable to accommodate angular movements and are generally equipped with joints that absorb the axial reaction forces. However due to these tension forces, they are not suitable for use as individual units to compensate combined movements. When pipelines are constructed, they are used to create joint systems that can easily accommodate large movements on any level.


These are used to compensate lateral movements (offset). They have braces that absorb axial reaction forces and are therefore not suitable for other types of movement. These braces are available both in a joint model and also a tie rod model.

Effect of compensator

In the design of piping compensation, the most economical way is natural compensation. Natural compensation is to compensate the thermal displacement by the flexibility of the natural bending shape of the pipeline. Obviously, the ability of natural compensation is limited. When natural compensation can not meet the requirements, it is usually necessary to consider installing metal bellows expansion joints and other compensation devices.

The main loads of the piping system are external loads (self weight of pipes and flowing medium, internal pressure, wind load, earthquake load, etc.) and displacement load. The purpose of setting up the pipe compensator is to eliminate the force acting on the equipment or pipe, and separate the complex pipe into a relatively simple and independent expansion section to ensure the best use effect of the expansion joint. The pipeline compensator can compensate the axial, transverse and angular thermal deformation of the absorption pipeline, absorb the vibration of the equipment, reduce the influence of the vibration of the equipment on the pipeline, and absorb the deformation amount of the earthquake and ground subsidence on the pipeline. The compensator is applied to the inlet and outlet of the hot and cold piping system, iron and steel plant, thermal power plant, flue gas desulphurization, dust removal equipment, air heating, auxiliary air blower and so on. Therefore, various compensators are widely applied. 

Once upon piping movements

When the piping is constructed or installed, usually no movement is favorable since it would induce excessive stress in normal piping arrangements. However, thermal and mechanical movements, caused by various internal and/ or external factors, are generally inevitable in any piping system. The possible piping movements include axial compression/ contraction, axial extension/ expansion, lateral deflection, angular movement, torsional movement, as well as vibration, etc. Among all piping movements, thermal expansion and contraction are more prevalent. In piping design, elbows, bends and piping loops normally provide adequate flexibility for piping thermal expansion and contraction

Pipe Compensator

Pipe Compensator manufacturer

As a manufacturer of the following models, we have extensive calculation procedures that allow us to design the parts to the optimum for the respective application.  

The metal compensator is used in gas pipelines to compensate the axial displacement of the pipeline system. Our modern production procedures guarantee fault-free operation, long service lives and a high level of safety. 

Pipe Compensator

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