How to correctly install pp air ducts through expansion joints and how to install corrugated expansi

pp air duct is a duct system for air transportation and distribution. There are two types of composite air ducts and inorganic pp air ducts. Ducts can be classified by section shape and material. PP air duct production Stainless steel air duct production is to apply sealant (such as neutral glass glue) in the gaps of the bite seam, rivet seam, flange flanging four corners and so on. Surface dust and oil should be removed before applying sealant. According to the cross-sectional shape, air ducts can be divided into circular air ducts, rectangular air ducts, oblate air ducts, etc. Among them, circular air ducts have small resistance and large height and size, and are complicated to manufacture. Therefore, the application is mainly based on rectangular ducts. According to the material, pp air ducts can be divided into metal air ducts, composite air ducts, and polymer air ducts.

    The metal rectangular corrugated compensator can mainly perform multi-directional compensation in a small installation space. The product also has the characteristics of good high temperature resistance, noise reduction and shock absorption. When installing the metal rectangular corrugated compensator, the following points should be paid attention to:

1. Before installation, the metal rectangular corrugated compensator should check its model, specification and pipeline configuration, and must meet the design requirements.

2. For the compensator with inner sleeve, attention should be paid to make the direction of the inner sleeve consistent with the flow direction of the medium, and the hinge rotation plane of the hinge type compensator should be consistent with the displacement rotation plane.

3. For the compensator that needs to be "cold tight", the auxiliary components used for pre-deformation should be removed after the pipeline is installed.

4. It is strictly forbidden to use the method of deformation of the corrugated compensator to adjust the installation tolerance of the pipeline, so as not to affect the normal function of the compensator, reduce the service life and increase the load of the piping system, equipment and supporting components.

5. During the installation process, the welding slag is not allowed to splash on the surface of the wave shell, and the wave shell is not allowed to suffer other mechanical damage.

6. After the installation of the piping system is completed, the yellow auxiliary positioning components and fasteners used for installation and transportation on the corrugated compensator should be removed as soon as possible, and the limiting device should be adjusted to the specified position according to the design requirements, so that the piping system has good performance under environmental conditions. adequate compensation capacity.

7. All movable components of the metal rectangular corrugated compensator shall not be stuck by external components or limit their range of activities, and the normal operation of each movable part shall be ensured.

1. Pipes with large deformation and deformation and limited spatial position.

2. Large-diameter pipes with large deformation and displacement and low working pressure.

3. It is necessary to limit the equipment that takes over the load.

4. Pipes that are required to absorb or isolate high-frequency mechanical vibrations.

5. Pipelines required to absorb earthquake or foundation settlement.

1. The internal pressure corrugated compensator is mainly used to compensate the axial displacement of the pipeline due to thermal expansion and contraction. It can also compensate for lateral displacement or combined axial and lateral displacement, and has the ability to compensate for angular displacement, but it is generally not used to compensate for angular displacement.

2. Calculation of the force of the metal bellows expansion joint on the support

Internal pressure thrust: F=100·P·A Axial elastic force: Fx=Kx·(f·K)

Lateral elastic force: Fy=Ky·Y Bending moment: My=Fy·L

Bending moment: Mθ=Kθ·θ Combined bending moment: M=My+Mθ

In the formula: Fx: Axial stiffness N/mm X: Axial actual displacement mm

Fy: lateral stiffness N/mm Y: lateral actual displacement mm

K: Angular stiffness N m/degree θ: Angular actual displacement (degree)

P: Working pressure Mpa A: Effective area of bellows cm2 (check sample)

L: Distance m from the midpoint of the expansion joint to the support

The transverse tie-rod expansion joint is composed of two corrugated pipes, intermediate nozzles and large tie rods, which can absorb the lateral displacement in any plane of the piping system. When lateral displacement occurs, the spherical nut and spherical washer on the large tie rod rotate, and the large tie rod also has the ability to withstand internal pressure thrust.

The rectangular corrugated compensator, also known as the rectangular metal corrugated expansion joint, is a pipeline compensation joint for hardware pipelines.